JPH04334842A - Optical writing device - Google Patents

Abstract

PURPOSE:To enable dot shaped exposure high in density with no minute shaped fluorescent material required by enabling electrons to be emitted selectively from fluorescent material coated in a belt shape and a number of electron sources. CONSTITUTION:When specified voltage is applied to the exciting electrode 17 of a point electron source 7, field emission takes place at a peak electrode 16, so that electrons are thereby emitted out of the source 7. And the electrons emitted from the source 7 are accelerated so as to be hit against an electrode 3 with positive voltage applied to the transparent anode electrode 3. In this case, the electrons emitted from the source 7 stimulates fluorescent material 4 coated over the electrode 3 so as to make it luminous, so that light emitted is outputted through the openings bored in the electrode 3, a glass substrate 2 and a glaring mask 13. In this case, when the voltage is changed, which is to be applied to each extracting electrode 17 of respective sources 7, based on image information to be recorded, the line of emission points can thereby be formed in response to image information. By this constitution, no minute shaped fluorescent material is required, dot shaped exposure high in density can thereby be obtained.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical writing device for converting image information to be recorded into an optical signal and writing it on a photoreceptor, and more particularly to an optical writing device applying the principle of a fluorescent display tube.

0002

[Background Art] In recent years, output devices for various information devices have been required to be high-speed and high-quality. The method of writing to is becoming popular. The optical writing devices used here include those that combine a rotating polyhedral mirror or galvano mirror with a laser, those that use an optical shutter array using liquid crystal, etc.
Items using array light sources such as light emitting diode arrays, plasma discharge element arrays, electroluminescent element arrays, CRTs
A combination of fiber and optical fiber is used. However, these optical writing devices have problems with reliability, cost,
Since the space taken up by these devices is not sufficient, research is underway into new types of optical writing devices, one of which is one that applies the principle of a fluorescent display tube.

An optical writing device that applies the principle of a fluorescent display tube is based on a directly heated triode vacuum tube structure.

[0004] A cross-sectional view of an example is shown in FIG. 5, and a plan view is shown in FIG.
are shown respectively. This optical writing device 81 constitutes a vacuum container with a glass substrate 82 and a face glass 89 bonded thereon with low melting point glass. An anode electrode 83 is formed on the glass substrate 82, and this anode electrode 8
3, phosphor dots 84 are applied by electrodeposition. These anode electrodes 83 and phosphor dots 84 are arranged in large numbers in rows, as shown in FIG.

[0005] Further, above this anode electrode 83,
A cathode filament 87, which is an electron source made of ultra-fine tungsten wire coated with an electron radioactive substance, is installed.
Furthermore, this cathode filament 87 and anode electrode 8
3, there is a grid electrode 86 made of metal mesh.
is held at a constant distance from the anode electrode 83 and cathode filament 87. Further, each of these electrodes is connected to a driving IC 88 installed on the substrate glass by wiring (not shown).

[0006] This optical writing device 81 is arranged opposite to the photoreceptor 90 with a rod lens 91 in between.

In the optical writing device configured as described above, when an alternating current or direct current voltage is applied to the cathode filament 87, the filament is heated and thermoelectrons are emitted from the electron emissive material coated thereon. A positive voltage is applied to the grid electrode 86 with respect to the cathode filament 87, and the thermoelectrons emitted from the cathode filament 87 are accelerated, and some of them flow into the grid electrode 86 and become grid current. The passed thermoelectrons head toward the anode electrode 83.

When a positive voltage is applied to the anode electrode 83 with respect to the cathode filament 87, the thermoelectrons passing through the grid electrode 86 are transferred to the anode electrode 83.
3 and becomes an anode current. At this time, the thermoelectrons stimulate the phosphor 84 coated on the anode electrode 83, causing it to emit light. Further, when a negative voltage is applied to the anode electrode 83 with respect to the cathode filament 87, the thermoelectrons passing through the grid electrode 86 are transferred to the anode electrode 83.
3, and the phosphor 84 does not emit light.

Therefore, the drive I placed on the board 82
C88 changes the voltage applied to each anode electrode 83 according to the image information to be recorded, and controls the light emission and
Selectively control non-emission. The light emitted from the phosphor 84 is transmitted through a face glass 89 and output, and is imaged on the surface of a photoreceptor 90 by a rod lens 91. Thereby, image information to be recorded can be written on the photoreceptor 90.

0010

However, in such an optical writing device, it is necessary to arrange a large number of fine dot-like phosphors in close proximity. Such dot-shaped phosphors are generally formed on the anode by electrodeposition, but at this time, the phosphors may adhere to areas other than the desired area, causing
Dots may connect with adjacent dots, causing a decrease in yield during manufacturing.

The present invention has been made to solve the above-mentioned problems, and is capable of producing high-density dots without requiring a finely shaped phosphor in an optical writing device that applies the principle of a fluorescent display tube. It is an object of the present invention to provide an optical writing device that can perform exposure of various types.

0012

[Means for Solving the Problems] In order to achieve this object, the optical writing device of the present invention applies the principle of a fluorescent display tube, in which phosphors are coated in strips and arranged in an array. It has a large number of electron sources, and is configured to be able to selectively emit electrons from those electron sources.

[0013]

[Operation] In the optical writing device of the present invention having the above configuration, the electron sources arranged in an array selectively emit electrons according to the image information to be recorded, so that the necessary portions of the band-shaped phosphor are only to emit light.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment embodying the present invention will be described below with reference to the drawings.

First, the configuration of this embodiment will be explained with reference to FIG.

A band-shaped transparent anode electrode 3 made of an ITO film is formed on a transparent glass substrate 2, and a band-shaped phosphor 4 of ZnO:Zn is coated on the transparent anode electrode 3 by electrodeposition. There is. Above this phosphor 4,
A large number of point electron sources 7 are arranged in close opposition to the phosphor 4.

Each point electron source 7 has an electrode 16 having a pointed head (hereinafter referred to as a pointed electrode) formed on an oxide substrate 19, and an electron extraction electrode 1 adjacent to the pointed electrode 16.
7 is placed on the substrate 19 with an insulating layer 18 interposed therebetween.

The transparent anode electrode 3, the pointed electrode 16,
The extraction electrode 17 is connected to a drive IC 8 (not shown).

The transparent anode electrode 3, phosphor 4, and point electron source 7 are held in vacuum by a sealed container formed by the glass substrate 2, the substrate 19, and a sealing member (not shown).

Furthermore, a light shielding mask 13 is provided on the outside of the glass substrate 2. This light shielding mask 13 is made of fluorescent material 4.
Openings 14 are respectively provided at positions facing the individual electron sources of the point electron source 7 via the openings 14 .

Next, the operation of this embodiment will be explained.

When a predetermined voltage is applied to the extraction electrode 17 of the point electron source 7, field emission of electrons occurs at the pointed electrode 16, and electrons are emitted from the point electron source 7. Here, by applying a positive voltage to the transparent anode electrode 3, the electrons emitted from the point electron source 7 are accelerated and impinge on the transparent anode electrode 3. At this time, the electrons emitted from the point electron source 7 are transferred to the phosphor 4 coated on the transparent anode electrode 3.
stimulates and causes it to emit light. This light emitted from the phosphor is output through openings made in the transparent anode electrode 3, the glass substrate 2, and the light-shielding mask 13.

Here, by changing the voltage applied to the extraction electrode 17 of each point electron source 7 depending on the image information to be recorded, it is possible to obtain a light emitting point array according to the image information.

The light-shielding mask 13 is provided for the purpose of not outputting the boundary of the light emitting point because the electrons emitted from the point electron source 7 spread out and blur the boundary of the light emitting point.

[0025] In this way, using a point electron source as an electron source,
By arranging them in an array so that only necessary portions emit electrons, high-density dot-shaped output light can be obtained without forming phosphors in dots. In addition, unlike cathode filaments, there is no need to install them in the air.
The brightness does not change due to vibration. Furthermore, uneven brightness due to voltage drop due to the resistance component of the filament does not occur. Moreover, since the electron source does not generate heat, the electron source and the phosphor can be brought close to each other, and the device can be made smaller.

Next, a second embodiment embodying the present invention will be described.

FIG. 2 shows a sectional view of the optical writing device 20 of this embodiment. Portions similar to those in the previous embodiment are designated by the same numbers, and descriptions thereof will be omitted.

In the optical writing device 21 of this embodiment, a light shielding mask 23 is formed as an insulating thin film adjacent to the phosphor 4 on a glass substrate. As in the previous embodiment, the point electron source 7
An opening is provided at a position facing the.

By providing the light-shielding mask 23 adjacent to the phosphor 4 in this way, it is possible to prevent the phosphor 4 located midway between the two point electron sources 7 from emitting light. Unwanted light can be removed more effectively than when a light shielding mask is provided outside the vacuum container as in the optical writing device 1 of the example.

Next, a third embodiment embodying the present invention will be described.

As shown in FIG. 3, the optical writing device 31 of this embodiment has a structure in which a grid electrode 36 is installed between the transparent anode electrode 3 and the point electron source 7 of the optical writing device 1 of the previous embodiment. It has become. This grid electrode 36 is placed on the glass substrate 2 with an insulating layer 35 in between.

By applying a positive voltage to the grid electrode 36, the electrons emitted from the point electron source 7 can be accelerated and guided to the transparent anode electrode 3. Thereby, the luminance of light emission can be improved.

Further, a fourth embodiment will be explained.

The optical writing device 41 of this embodiment has a structure in which a large number of linear grid electrodes 46 are arranged between the transparent anode electrode 3 and the point electron source 7 of the optical writing device 1 of the first embodiment. ing. This grid electrode 46
As shown in FIG. 4, the point electron sources 7 are arranged so as to be located between the individual point electron sources of the point electron sources 7 arranged in the longitudinal direction of the phosphor 4.

Here, a negative voltage is normally applied to each grid electrode 46, and a positive voltage is applied only to those located on both sides of the point electron source 7 selected according to the information to be written. Ru. By doing so, the electrons emitted from the point electron source 7 can be selectively accelerated. Therefore, due to the spread of electrons, the phosphor 4
It is possible to prevent the light emitting region from expanding, and output light with high contrast can be obtained.

The present invention is not limited to the embodiments described in detail above, and various changes can be made without departing from the spirit thereof.

For example, the point electron sources can be arranged not in a single row but in a staggered pattern or in multiple rows, and the point electron sources do not utilize field emission but avalanche amplification of p-n junctions. Other types of point electron sources may also be used, such as those that utilize action. The shape of the grid electrode used in the fourth embodiment does not have to be linear, and may be, for example, plate-shaped.

Although the explanation here is based on a triode type fluorescent display tube, it can also be applied to other types of fluorescent display tubes, such as a tetrode type that is provided with electrodes to eliminate the influence of accumulated charges. You can also.

[0039] The materials mentioned in the above explanation are only examples.
For example, tin oxide or the like can be used for the transparent anode electrode, and instead of the transparent anode electrode, it is also possible to use an electrode formed to allow light transmission by providing a slit or the like. Furthermore, by changing the type of phosphor, it is possible to obtain a luminescent color that corresponds to the sensitivity of the photoreceptor material.

The photoreceptor used here includes a photoconductor used in electrophotography based on the Carlson process, a silver salt film, and a microcapsule photosensitive paper.

[0041]

[Effects of the Invention] As is clear from the above explanation, the optical writing device of the present invention provides an optical writing device capable of high-density dot-like exposure without requiring a finely shaped phosphor. be able to.

[Brief explanation of drawings]

FIG. 1 is a sectional view for explaining the configuration of a first embodiment embodying the present invention.

FIG. 2 is a sectional view for explaining the configuration of a second embodiment embodying the present invention.

FIG. 3 is a sectional view for explaining the configuration of a third embodiment embodying the present invention.

FIG. 4 is a cross-sectional view in the sub-scanning direction for explaining the configuration of a fourth embodiment embodying the present invention.

FIG. 5 is a cross-sectional view for explaining the configuration of a conventional optical writing device.

FIG. 6 is a plan view for explaining the configuration of a conventional optical writing device.

[Explanation of symbols]

1, 21, 31, 41 Optical writing device 2 Glass substrate 3 Transparent anode electrode (electrode that can transmit light) 4 Fluorescent material 6, 36, 46 Grid electrode (auxiliary electrode) 7 Point electron sources 13, 23 Light shielding mask (light shielding member) )16 Pointed electrode 17 Extracting electrode

Claims (3)

[Claims] Claim 1: A device comprising a light-transmissible electrode, a phosphor coated on the electrode, and an electron source disposed opposite to the phosphor, and these phosphors and the light-transmissible electrode , an optical writing device in which an electron source is held in a vacuum and is configured to be able to extract light emitted from the phosphor,
An optical writing device characterized in that the phosphor is coated in a strip-like shape, and the electron source is a point electron source arranged in large numbers facing the strip-shaped phosphor. 2. The optical writing device according to claim 1, further comprising an auxiliary electrode provided between the phosphor and the point electron source. 3. The optical writing device according to claim 2, wherein a large number of said auxiliary electrodes are arranged corresponding to said point electron sources.