JPH0911537A - Field emission type print head - Google Patents

Abstract

PURPOSE: To eliminate leakage light emission without narrowing the interval between a cathode and an anode by forming an anode line substantially perpendicularly oppositely to a gate line, forming a phosphor in a stripe state in an axial direction, and always setting the potentials of the second gate leading electrode and the anode concentration to a low level. CONSTITUTION: N pieces of gate lines GT11 to in are connected to the first gate leading electrode GT1, and (n+1) pieces of concentrating electrodes GT21 to 2(n+1) are connected to the second gate leading electrode GT2. The gate driving voltage which is always positive at the time of operating is supplied to the electrode GT1, and electrons responsive to image data of one line supplied to cathode lines C1 to Cn are emitted from the field emission cathode FE1 to FEn. At this time, the potential of the second electrode GT2 is always set to a low level. In the case of the gate GT13 as an example, the potentials of the concentrating electrodes GT23, GT24 are set to a low level, and the electrons emitted from the gate line 13 are not diffused but concentrated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print head for an optical printer, and more particularly to a print head using a field emission device.

[0002]

2. Description of the Related Art Conventionally, an optical printer has been known. An outline of the optical printer will be described with reference to FIG. The film 120 is coated with a photosensitizer such as silver halide (silver salt), and the lower side of the film 120 is exposed to light reflected by the mirror 121 to be exposed. . The light emitted to the film 120 is emitted from the print head 125,
Image data for each line is supplied to the print head 125, and light for each line modulated by this image data is emitted in the main scanning direction perpendicular to the paper surface. Then, the print head 125 is sub-scanned as indicated by the arrow, so that one image is printed on the film 120 by the line sequential method.

The SLA 122 is a SELFOC lens array, which is a lens for focusing the light emitted from the print head 125 on the film 120. The mirror 123 is a mirror for guiding light to the SLA 122. Also, the RGB filter 124
Is an RGB filter of light of three primary colors for printing a color image on the film 120. When printing a color image, the same one line of image data is decomposed into three image data of R (red), G (green), and B (blue), and RGB filters are applied to the image data of each color. 124 is sequentially moved to perform three main scans. That is, one line of color image is recorded on the film 120 by three main scans.

Conventionally, a light emitting diode (LED) or a thermoelectron emission type fluorescent display tube has been used as a light source of a print head of such an optical printer, but in recent years, semiconductor fine processing technology has been utilized. Thus, it becomes possible to form micron-sized field emission devices on a substrate in the form of an array, and a field emission type print head using this field emission device array as an electron source has been proposed (Japanese Patent Laid-Open No. Hei 4).
-43539 publication).

FIG. 7 shows an example of the structure of this conventional field emission printhead. 7, (a) is a schematic plan view, (b) is a schematic cross-sectional view taken along the line AA ′,
(C) is a detailed sectional view taken along the line BB '. As shown in the figure, the field emission printhead includes a first flat substrate 10 on which a plurality of field emission devices 105 are formed.
1 and a second flat substrate 102 which is arranged so as to face the first flat substrate 101 and on which a phosphor 106 and the like are formed;
A sandwiching body 103 that keeps the space between the planar substrate 101 and the second planar substrate 102 constant, and a vacuum layer 104 surrounded by the first planar substrate 101, the second planar substrate 102, and the sandwiching body 103.
It is composed of

The first flat substrate 101 is made of an n-type silicon single crystal substrate and has a silicon oxide film (SiO ₂ film) except for the field emission device 105 and the substrate contact electrode 107.
It is covered with 101 '. The second flat substrate 102 is made of a transparent glass substrate and has a transparent anode electrode 1 on its surface.
09 and the fluorescent substance 106 are laminated | stacked and formed. A field emission device 105 having a cathode electrode and a gate electrode and a phosphor 106 having an anode electrode are arranged so as to face each other with a vacuum layer 104 interposed therebetween, and a pair of them constitutes a unit light source. Each unit light source has one field emission device which is separated from each other and divided into gate electrodes arranged in an array.
The cathode electrode of each field emission element shares the silicon single crystal plate, and the anode electrode is also common.

As shown in FIG. 7C, one field emission device includes a plurality of projecting cathode electrodes (emitters) 111 formed on the surface of the first flat substrate 101, and SiO 2.
_The gate electrode 112 is formed through the _two films 101 'and has openings near the respective protrusions. The gate electrode 112 is formed separately in each field emission device. In the above description, a silicon single crystal substrate is used for the first flat substrate 101, and the protrusion is formed by utilizing anisotropic etching of the silicon single crystal substrate.
It is also possible to use an insulating substrate having metal electrodes and metal protrusions, or a conductive substrate having metal protrusions formed thereon.

In the unit light source configured as described above,
With the silicon single crystal substrate 101 grounded through the substrate contact electrode 107, the anode contact electrode 11
The anode voltage V _ak is applied to the phosphor 106 through the anode electrode 109 and the anode electrode 109, and the gate contact electrode 108
When a gate voltage V _gk is applied to the gate electrode of the field emission device 105 through the electric field emission device, the electric field of the gate electrode is applied to the protrusion of the cathode electrode of the field emission device 105, and electrons are emitted from the tip of the protrusion. The field-emitted electrons are accelerated by the anode voltage and reach the phosphor 106, causing the part of the phosphor 106 facing the device to emit light.

In this way, the emitted light is radiated through the transparent anode electrode 109 and the second flat substrate 102, and one line of image data is luminescent recorded on a recording medium such as a film. In this case, an image can be recorded by a line-sequential scanning method in which the recording medium or the print head itself is moved as described above and the image data for the next one line is recorded. At this time, a color image can be recorded by moving the RGB filter 124 and performing main scanning as shown in FIG. Since such a field emission print head is manufactured by utilizing the semiconductor fine processing technology, it is possible to realize high resolution.

[0010]

However, in the above-mentioned conventional field emission print head, about 60 ° from the tip of the sharpened cathode electrode from which electrons are field-emitted.
Since the electrons are emitted with a spread of, the electrons that have reached the anode spread to some extent. Then, there is a problem that electrons may hit adjacent pixels on the anode side to cause leakage light emission. To prevent this, the pixel pitch may be increased, but if the pixel pitch is increased, the resolution will be reduced. Further, if the distance between the cathode and the anode is narrowed, the spread of the electrons can be suppressed, but if the distance between the cathode and the anode is narrowed, the drive voltage of several hundred volts applied to the anode can be withstood. Cannot be done, and the distance cannot be reduced.

Therefore, it is an object of the present invention to provide a field emission printhead in which leakage light emission does not occur without increasing the pixel pitch and narrowing the distance between the cathode and the anode.

[0012]

In order to achieve the above object, a field emission print head of the present invention comprises a plurality of cathode lines formed on a cathode substrate and an insulating layer on each of the cathode lines. A plurality of gate lines formed via the gate lines, a plurality of focusing electrodes arranged between the gate lines, and outside the start end and the end of the gate line, and a plurality of the gate lines are connected A gate lead-out electrode, a second gate lead-out electrode to which the plurality of focusing electrodes are connected, a plurality of cathode lines and a plurality of gate lines are overlapped with each other. The field emission array and the field emission array formed on each of the gate lines and facing the cathode substrate. An anode substrate having an anode line electrode coated with a phosphor is provided, the anode line electrode is formed so as to face the gate line and be substantially orthogonal to the gate line, and the anode line of the anode line. It is composed of two anode focusing electrodes arranged on both sides, a phosphor is formed on the anode line in a stripe shape in the axial direction of the anode line, and the potential of the second gate extraction electrode is always low level. In addition, the electric potentials of the two anode focusing electrodes are always kept at a low level.

Further, in the field emission print head, the anode line is formed of a metal thin film, and a slit is provided in the axial direction, and the phosphor is coated so as to cover the slit. Furthermore, the focusing electrode is arranged at a position higher than the gate line so as to be closer to the anode substrate.

[0014]

According to the present invention, the potentials of the focusing electrodes arranged between the gate lines and outside the start and end of the gate lines are low when the gate lines are driven. The driven gate line is sandwiched between the focusing electrodes of low potential, and the field-emitted electrons can be focused. Further, the driven anode line on the anode side is sandwiched by the anode focusing electrodes having a low potential, so that electrons can be focused also on the anode side. Therefore, it is possible to prevent the leakage light emission of the adjacent pixels without deteriorating the resolution and without adopting the means for lowering the anode potential to lower the luminance.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a field emission print head according to the present invention will be described with reference to FIGS.
1 shows an example of a gate line and a cathode line when the cathode substrate 1 constituting the field emission printhead of one embodiment is viewed from above, and FIG. 2 shows the field emission printhead of the present invention. FIG. 3 is a partial cross-sectional view taken along the line AA in FIG. 3, and FIG. 3 is a perspective view of the field emission printhead according to the present invention, showing the configurations of gate lines, cathode lines, and anode lines. ing.

In the field emission print head of the present invention, as shown in FIG. 2, a plurality of cathode lines C1, C2, C3, ... Cn (cathode line C (n 2), C (n-1), and Cn are shown), and a field emission array is formed on each of the cathode lines C1, C2, C3, ... Cn. A plurality of cone-shaped emitters 3 are formed. Further, an insulating layer 2 made of SiO ₂ or the like is formed on the cathode substrate 1, and n gate lines GT11 to GT1n (gate line G in the figure is formed on the insulating layer 2).
Only two of T1 (n-1) and GT1n are shown. ) And focusing electrodes GT21-GT2 (n + 1) arranged between the gate lines GT11-GT1n and outside the gate lines GT11, GT1n (only two focusing electrodes GT2n, GT2 (n + 1) are shown in the figure). Has been formed).

The focusing electrodes GT21 to GT2 (n +
In order to bring about the action of focusing the emitted electrons by 1), the potential of the second gate extraction electrode GT2 is set so that the potentials of the focusing electrodes GT21 to GT2 (n + 1) are set to a low level (which may be zero level or negative level). Is always low level (may be zero level or negative level). In addition, the cathode lines C1 to Cn and the gate line G
Field emission array FE including T11 to GT1n and emitter 3
1 to FEn are configured, but the field emission array FE
1, FE3, ... FE (n-1) are formed in a striped shape as shown in FIG. By the way, as shown in FIG. 1, the electrode widths of the gate lines GT11 to GT1n are formed wider than the electrode widths of the cathode lines C1 to Cn, and the focusing electrodes GT21 to GT2n are wider than the electrode widths of the gate lines GT11 to GT1n. It is narrowly formed.

Further, the anode substrate 10 is arranged facing the cathode substrate 1 with a predetermined gap, and the anode electrode formed on the anode substrate 1 has a gate line GT.
It is composed of an anode line A11 having stripe-shaped slits 14 arranged substantially orthogonal to 11 to GT1n, and two anode focusing electrodes A12 arranged on both sides of the anode line A11.

The anode line A11 is provided with a slit 14 for taking out the light emitted from the phosphor 12, and the stripe-shaped phosphor 12 covers the slit 14.
Is attached. The anode line A11 and the anode focusing electrode A12 are made of a metal thin film such as aluminum. The fluorescent substance 12 is one in which the electrons emitted from the above-mentioned field emission arrays FE1 to FEn hit and emit light. The field emission arrays FE1 to FEn are formed in a stripe shape in a direction substantially orthogonal to the anode line A11. Therefore, the anode substrate 1 with respect to the cathode substrate 1 when the cathode substrate 1 and the anode substrate 10 are bonded to each other to produce a field emission printhead.
The allowable range of zero alignment accuracy can be expanded.

Further, an anode line A11 made of a metal thin film
By providing the slit 14 in, it becomes possible to obtain a high-definition light emission pattern at the thin film level.
The tolerance range of the patterning accuracy of the phosphor 12 can be widened. Therefore, the field emission printhead of the present invention can be easily manufactured. The width of the slit 14 is about 85 μm at a resolution of 300 dpi,
Resolution is about 42 μm at 600 dpi, resolution is 1200
It becomes about 21 μm in dpi.

The cathode substrate 1 and the anode substrate 10
And a side plate (not shown) form a vacuum-tight container,
The inside is a high vacuum. Further, since the light emission of the phosphor 13 is taken out through the anode substrate 10, the anode substrate 10 is made of glass. However, the cathode substrate 1 can also be made of glass. Further, the anode line A11 and the anode focusing electrode A12 are formed of a metal thin film such as aluminum as described above, but the reflectance of the metal thin film is large and the anode substrate A11 is used to prevent reflection when the metal thin film is aluminum. A titanium oxide film may be provided at the interface between 10 and the aluminum thin film to form the antireflection layer. Thereby, light emission with high contrast can be obtained.

Further, the anode line A11 and the anode focusing electrode A12 can be made of a transparent conductive material such as ITO. The structure of the anode electrode in this case is shown in FIG.
As shown in FIG. 7, since the anode line A11 is transparent, it is not necessary to provide the slit 14 to take out the emitted light of the phosphor 12, and as shown in the figure, the stripe-shaped phosphor 12 is formed below the anode line A11. It is supposed to have a structure.

Next, a method of driving the field emission print head of the first embodiment thus constructed will be described. As described above, the n gate lines GT11 to GTn are connected to the first gate extraction electrode GT1 and the (n + 1) focusing electrodes GT21 to GT2 (n + 1) are connected to the second gate extraction electrode GT2. First gate extraction electrode GT
1 is always supplied with a positive gate drive voltage during operation,
From the field emission cathodes FE1 to FEn, electrons corresponding to the image data for one line supplied to the cathode lines C1 to Cn are emitted. At this time, the potential of the second gate extraction electrode GT2 is always at the low level (or may be at the zero level or the negative level).

Then, for example, the first gate extraction electrode GT1
When the gate line GT13 is taken as an example, the potentials of the focusing electrode GT23 and the focusing electrode GT24 located on both sides of the gate line GT13 are set to a low level. In this case, the low-level focusing electrodes GT23 and GT24 arranged on both sides are provided.
Under the influence of the electric field of, the electrons emitted from the gate line GT13 are focused without being diffused. In this way, the electrons that are field-emitted by driving the first gate extraction electrode GT1 are always at the low level (or zero level or negative level) of the focusing electrode GT2.
By the action of 1 to GT2 (n + 1), they are focused and directed toward the anode line A11.

Since there is no gate line outside the gate line GT11 and the gate line G1n, electrons are focused by providing focusing electrodes GT21 and GT2 (n + 1). On the anode side, a positive drive voltage is constantly supplied to the anode line A11 during operation, and the anode focusing electrode A12 is always at a low level potential (zero potential or
It may be a negative potential. ) Is supplied.

Then, the anode line A11 comes to be sandwiched by the low-level anode focusing electrodes A12, so that the gate lines GT11 to GT are operated by the action of the electric field.
The electrons emitted from 1n are more focused and reach the anode line A11. In this case, the direction in which the electrons are focused is the direction orthogonal to the anode line A11, but the focusing electrodes GT21 to GT2 (n +) described above are used.
The direction in which the electrons are focused by the action of 1) is parallel to the anode line A11, so that the electrons emitted from each of the driven field emission arrays FE1 to FEn have a circular focusing cross section. It will be efficiently focused. In this way, an image for one line is recorded on the recording medium. Thereafter, similarly, line-sequential scanning is sequentially performed, and an image of one screen is recorded on the recording medium.

Next, FIG. 5 shows a modification of the field emission print head of the present invention described above. This drawing is a partial cross-sectional view of a modification of the field emission print head, and the same reference numerals as those in FIG. 2 indicate the same parts. In this modification, the formation positions of the focusing electrodes GT21 to GT2 (n + 1) are made different. In this modification, as shown in the figure, an insulating layer 2 is further formed on the insulating layer 2 on which the gate lines GT11 to GT1n are formed, and the focusing electrodes GT21 to GT2 (n + 1) are formed thereon. There is. Thereby, the focusing electrodes GT21 to GT2 are
Since (n + 1) comes closer to the anode line A11 than the gate lines GT11 to GT1n, the electron focusing degree is further improved. Other configurations and operations are the same as those of the above-described embodiment, and thus the description thereof will be omitted.

In the field emission print head of the present invention described above, the line pitch of the cathode lines C1 to Cn corresponding to the pixel pitch has a resolution of 300d.
About 85 μm at pi, about 42 μ at resolution of 600 dpi
m, and the resolution is about 21 μm at 1200 dpi. The cathode lines C1 to Cn may be drawn out from both sides of the cathode substrate, and the line pitch in that case is double the above.

[0029]

As described above, according to the present invention, the potentials of the focusing electrodes arranged between the gate lines and outside the start end and the end of the gate lines are low when the gate lines are driven. Since the potential is set, the driven gate line is sandwiched between the focusing electrodes of low potential, and the field-emitted electrons can be focused. Furthermore, on the anode side, the anode line that is selectively driven is
Since it is sandwiched by the anode focusing electrodes that have a low potential,
Electrons can also be focused on the anode side.

Further, by forming the focusing electrode closer to the anode line than the gate line, the emitted electrons can be more focused. Therefore, it is possible to prevent the leakage light emission of the adjacent pixels without deteriorating the resolution and without adopting the means for lowering the anode potential to lower the luminance.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a gate line and a cathode line of an embodiment of a field emission print head of the present invention.

FIG. 2 is a partial side sectional view showing the structure of an embodiment of the field emission printhead of the present invention.

FIG. 3 is a perspective view showing a configuration of a gate line, a cathode line, and an anode line of an embodiment of the field emission printhead of the present invention.

FIG. 4 is a diagram showing a modified example of an embodiment of the field emission printhead of the present invention.

FIG. 5 is a diagram showing a timing chart of drive pulses for driving the field emission printhead of the present invention.

FIG. 6 is a diagram showing a schematic configuration of a conventional optical printer.

FIG. 7 is a top view, a front sectional view, and a side sectional view showing a schematic configuration of a conventional field emission printhead.

[Explanation of symbols]

 1 cathode substrate 2 insulating layer 3 emitter 4 opening 10 anode substrate 13 phosphor 14 slit 101 first flat substrate 102 second flat substrate 103 sandwiching body 104 vacuum layer 105 field emission device 107 substrate contact electrode 108 gate contact electrode 110 anode contact Electrode A11 Anode line A12 Anode focusing electrode C1, C2, C3 ..., Cn Cathode line FE1, FE2, ... FEn Field emission array GT1, GT2 Gate extraction electrode GT11 to GT1n Gate line GT21 to GT2 (n + 1) Focusing electrode

Claims (3)

[Claims] 1. A plurality of cathode lines formed on a cathode substrate, a plurality of gate lines respectively formed on the cathode lines with an insulating layer interposed therebetween, between the gate lines, and between the gate lines. A plurality of focusing electrodes arranged outside the start end and the end, a first gate extraction electrode to which the plurality of gate lines are connected, and a second gate extraction electrode to which the plurality of focusing electrodes are connected, A field emission array formed in a striped shape in each portion where the plurality of cathode lines and the plurality of gate lines are overlapped with each other; An anode substrate having anode line electrodes coated with phosphors corresponding to the field emission arrays formed on the respective anode substrates; -Line electrodes, an anode line formed so as to be substantially perpendicular to the gate line opposite to the gate lines, disposed on both sides of the anode lines 2
A plurality of anode focusing electrodes, phosphors are formed on the anode line in a stripe shape in the axial direction of the anode line, and the potential of the second gate extraction electrode is always kept at a low level. A field emission printhead, characterized in that the anode focusing electrode of a book is always kept at a low level. 2. The anode line is formed of a metal thin film, and a slit is provided in the axial direction thereof, and the phosphor is coated so as to cover the slit. Item 7. A field emission printhead according to item 1. 3. The field emission printhead according to claim 1, wherein the focusing electrode is arranged at a position higher than the gate line so as to be closer to the anode substrate.