JPS6168845A - Optical writing device - Google Patents

Abstract

PURPOSE:To improve the luminous efficiency of an optical writing device by forming an insulating layer on the area of the dot-array fluorescent tube other than dot-like phosphor areas, installing a first grid electrode on the insulating layer and installing a second grid electrode between the first grid electrode and the cathode. CONSTITUTION:The symbol 16 represents an anode and the symbol 18 represents a filament. The area of one surface of a base plate 12 other than phosphor areas is coated with a first insulating layer 22. A first grid electrode 23 is installed on the first insulating layer 22. A second insulating layer 24 composed of glass is formed on the base plate 12 and a second grid 25 is formed on the second insulating layer 24. Thermions accelerated by the second grid electrode 25 and the anode 16 are concentrated on the phosphor 17 by applying a given voltage (V1), lower than voltage (V2) applied to the second grid electrode 25, to the first grid electrode 23. In this optical writing device the first grid electrode 23 acts as a focusing lens. Consequently, the luminous efficiency of the device is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an optical writing device used in an optical printer or the like, and more particularly to an optical writing device constructed from a dot array fluorescent tube.

2. Description of the Related Art In recent years, an electrophotographic optical printer for recording output from a computer or the like has been developed in which an optical writing device for converting the output into an optical signal is composed of a dot array fluorescent tube.

A conventional dot array fluorescent tube like this will be explained with reference to FIGS. 6 and 7. This dot array fluorescent tube 1 is constructed by placing a face glass 4 on a substrate 2 with a spacer glass 3 interposed therebetween, and then placing the face glass 4 in a vacuum container. form 5.

In this vacuum container S, a large number of anode electrodes 6 are arranged on the surface of the substrate 2, a dot-shaped phosphor 7 is formed on the surface of each anode electrode 6, and a filament is formed corresponding to the cathode electrode 6. (Cathode electrode) 8 is provided, and one grid electrode (grid electrode [1) 10 is interposed between the anode electrode 6 and the filament 8 on the substrate 2 with an insulating layer S interposed therebetween.

To specifically explain the method of forming this dot array fluorescent tube 1, first, an anode electrode 6 is formed on the substrate 2, an insulated calendar date is formed on the anode electrode 6 by screen printing except for a width of 200 μm, and then, for example, A dot-shaped phosphor 7 of 60×60 μm is formed in the center of the part without the insulating layer 9 (200 μm part) by electrodeposition or photoetching,
Next, the grid electrode 10 is fixed onto the insulating layer S.

In this dot array fluorescent tube 1 configured in this way, thermoelectrons are emitted by supplying an AC voltage of, for example, 20 V to the filament 8, and at this time, the anode electrode 6
By applying a positive voltage of, for example, 40 V to the grid electrode 10 and a positive voltage of, for example, 20 V to the grid electrode 10, the hot electrons are accelerated by the grid electrode 10 and hit the phosphor 7, so that the phosphor 7 emits light.

Therefore, by selecting the anode electrode 6 to which a voltage is applied according to the printed information 5, light corresponding to the image, etc. is emitted to the outside through the face glass 4, and the photoreceptor is charged by this emitted light. By scanning the top, an electrostatic latent image can be formed, and by performing a normal electrostatic recording process thereafter, a desired image can be recorded on the recording paper.

However, in such a dot array fluorescent lamp 1, since a part of the anode electrode 6 is exposed, the potential distribution near the anode electrode 6 becomes as shown by the broken line in FIG. A part of it flows to the exposed part of the anode electrode 6 where there is no phosphor 7 and does not contribute to light emission.
Luminous efficiency deteriorates.

Therefore, when an optical writing device is constructed using this dot array fluorescent tube 1, the anode voltage applied to the anode electrode must be increased in order to cause each light emitting dot to emit high-intensity light, and a high-voltage driving IC is required. At the same time, a problem arises in that the phosphor deteriorates more rapidly.

Purpose This invention was made in view of the above points, and an object thereof is to improve the luminous efficiency of a dot array fluorescent tube.

In order to achieve the above object, the present invention forms an insulating layer covering a portion of the dot array fluorescent tube other than the dot-shaped phosphors, provides a first grid electrode on the insulating layer, and A second grid electrode is provided between the grid electrode and the anode electrode.

Hereinafter, a detailed explanation will be given based on one embodiment of the present invention.

1 and 2 are a side sectional view and a plan view of essential parts showing an example of a dot array fluorescent tube constituting an optical writing device embodying the present invention.

This dot array fluorescent tube 11 is mounted on a face glass 1 via a spacer glass 13 on a substrate 12 made of glass or the like.
4 is placed to form a vacuum container 15. Note that these glasses are usually bonded using low melting point glass.

In addition, a transparent electrode film is formed on the inner surface of the face glass 14 to prevent the influence of an external electric field and to prevent disturbance of electric field distribution due to charging of the surface by thermionic beam. It is recommended to apply a grid potential.

Inside the vacuum vessel 15, a large number of anode electrodes 16 made of a metal thin film such as Aa are arranged in a row in the longitudinal direction of the vacuum vessel 15 on the substrate 12, and the surface of the anode electrode 16 is doped with, for example, Zn. A dot-shaped phosphor 17 whose main component is Zn○ is formed to form a light-emitting dot.

On the other hand, in the upper part of the vacuum vessel 15, a filament 18 formed by applying an oxide to a thin tungsten wire is placed along the arrangement direction of the anode electrodes IS, corresponding to the anode electrode 16, as a support 1!3.1! 3, the spring member 20.2
It is arranged with a tension of 0.

A first insulating layer 22 is formed on the substrate 12 between the anode electrode 16 and the filament 18, and covers the portion other than the phosphor 17 made of SiO2. In addition to providing the first grid electrode 23, a second insulating layer 24 made of glass is formed on the substrate 12,
A second grid electrode 25 is provided on this second insulating layer 24.

To explain specifically how to form this dot array fluorescent tube 11, first, an anode electrode 16 is formed on a substrate 12 made of glass or the like by photoetching or the like, and a first insulating layer 22 is formed on the anode electrode 16 by a sputtered film of SiO. A first grid electrode 23 is formed thereon as a thin film.

Thereafter, referring also to FIG. 3, in order to form the phosphor 17, a window is opened in the first grid electrode 23 and the first insulating layer 22 by a photoetching method, and this window-opened portion W
By applying a phosphor to the anode electrode by electrodeposition (electrophoresis) to form the phosphor 17 on the anode electrode, parts other than the phosphor 17 are covered with the first insulating layer 22, and the first M
! The structure is such that a first grid electrode 23 is provided on the edge layer 22.

Next, a second insulating layer 24 is formed on the substrate 12, and a second grid electrode t! 25 by forming the first
The second grid electrode 25 is interposed between the grid electrode 23 and the filament 18.

Note that the second grid electrode 25 has slits 25 .corresponding to the rows of the phosphors 17 . is formed to prevent the emitted light from each minute light emitting dot from being blocked, thereby improving the effectiveness of the emitted light and suppressing variations in the brightness of the emitted light.

In addition, each anode type ti16 of this dot array fluorescent tube 11
are alternately (staggered) extended on both sides of the outside of the vacuum container 15, and are connected to drive ICs (not shown) by wire bonding or the like to constitute an optical writing device.

In the dot array fluorescent tube 11 constructed in this way, thermoelectrons are emitted by heating the filament 18 by supplying an alternating current voltage of, for example, 10 to 2 degrees V.

At this time, by applying a voltage of, for example, +40 V to the anode electrode 1 day while applying a voltage of, for example, +20 V to the second grid electrode 25, the thermoelectrons are accelerated by the second grid electrode 25 and are transferred to the phosphor 17. When hit, the phosphor 17 emits light. Note that the voltage applied to the first grid electrode 23 will be described later.

At this time, the emission spectrum when the phosphor 17 is ZnO:Zn has a peak at 505 nm.

The characteristics are wide ranging from 410 nm on the short wavelength side to 650 nm on the long wavelength side.

Therefore, by selectively applying a driving voltage to each anode 416 according to print information, desired light emitting dots can be caused to emit light to print.

By the way, in this driver 1-array fluorescent tube 11,
As mentioned above, since the part other than the phosphor 17 on the anode electrode is covered with the first insulating layer 22, the anode electrode 16 is not exposed and the second grid electrode 25 and the first insulating layer 22 are covered with the first insulating layer 22. A first grid electrode 23 having a window approximately the same shape as the phosphor 17 is provided between the two electrodes.

Therefore, a predetermined voltage v1(V2)V, which is lower than the voltage v2 applied to the second grid electrode 25, is applied to the first grid electrode 23.
However, by applying (l can be either positive or negative), the potential distribution near the anode electrode 16 becomes as shown by the broken line in FIG. 4, so that the heat accelerated by the second grid electrode 25 and the anode electrode 16 Electrons concentrate on the phosphor 17 portion.

In other words.

Since the first grid electrode 23 acts as a focusing lens, the luminous efficiency is improved.

This makes it possible to emit high-intensity light by driving at a low voltage, thereby making it possible to lower the voltage of the driving IC and extend the life of the phosphor.

Furthermore, as described above, the first insulating layer 22 and the first grid electrode 2
By opening the window in 3 and forming the phosphor 17,
It becomes easier to create the grid electrode, and since the dimensions of the phosphor 17 are regulated to the size of the opening in the first insulating layer 22, the size of one light-emitting dot becomes approximately constant.

As a result, in conventional methods of forming phosphors, the phosphors protrude from the electrode portions when electrodeposition is used.

Also, the size varies with the photoetching method.

Although variations in the size of each light-emitting dot caused unevenness in the amount of light, such unevenness in the amount of light can be suppressed.

FIG. 5 is a schematic configuration diagram showing an example of an optical printing apparatus using an optical writing device embodying the present invention.

In this optical printing device (optical printer), the photoreceptor drum 31 is rotated in the direction of arrow P when printing is started, and the surface of the photoreceptor drum 31 is uniformly charged by the charging charger 32.

An optical writing device 3 is constructed by connecting a driving IC to a dot array fluorescent tube embodying the present invention.The optical writing device The light emitted from the 33 dot array fluorescent tubes is irradiated onto the photoreceptor drum 31 via a 1-magnification imaging element 34 made of a focusing optical fiber lens, etc., and an electrostatic charge is generated on the photoreceptor tram 31 according to the printed information. Form a latent image.

After that, the WI@ latent image on this photoreceptor drum 31.

A developing device 35 applies a developing agent to visualize the image, and the image is transferred onto a recording paper 37 fed by a transfer charger 36 .

Then, this recording paper is passed through a fixing device (not shown), subjected to a fixing process, and then discharged to an external paper output tray, etc. After erasing the residual charge on the photoreceptor tram 31 with a static elimination lamp for 3 days, the remaining developer is removed. is removed using a cleaner for 3 days to prepare for the first recording step.

In the above embodiment, an example in which one second grid electrode was provided was described, but a plurality of second grid electrodes may be provided.

Effects As explained above, according to the present invention, the luminous efficiency of the tondo array fluorescent tube, which is advantageous for optical writing, is improved.

[Brief explanation of the drawing]

1, 2, and 3 are side sectional views of a dot array fluorescent tube showing an embodiment of the present invention. A principal part plan view and a principal part enlarged plan view. FIG. 4 is an explanatory diagram showing the potential distribution near the anode electrode. FIG. 5 is a schematic configuration diagram showing an example of an optical printing device using an optical writing device embodying the present invention. FIGS. 6 and 7 are a side sectional view and an enlarged main part of a conventional dot array fluorescent tube. The plan view and FIG. 8 are also explanatory diagrams showing the potential distribution near the anode electrode. 11... Dot array fluorescent tube 12... Substrate 15.
...Vacuum container 16...Anode electrode 17...
Phosphor 18... filament (cathode electrode 22...
...First wA3 layer 23...First grid electrode 2
4...Second insulating layer 25...Second grid electrode (1 idiot) - Figure 1 Figure 2 Figure 3 Figure 6 Figure 7 Figure 8 Z'/0 Procedure amendment (own ship November 13, 1980

Claims (1)

[Claims] 1. In an optical writing device configured with a dot array fluorescent tube having a large number of anode electrodes having dot-shaped phosphors formed on the surface thereof and cathode electrodes corresponding to the anode electrodes, the dot-shaped fluorescence of the dot array fluorescent tube An insulating layer is formed to cover parts other than the body, a first grid electrode is provided on the insulating layer, and a second grid electrode is provided between the first grid electrode and the cathode electrode. optical writing device.