JP2002298768A - Fluorescent display tube and its driving method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorescent display tube of rib-grid structure and its driving method whereby it is possible to generate light emission free of shadow through a simple control procedure. SOLUTION: The grid electrodes 24 are installed independently of one another between the rows of anodes 32 and therefore, are selectable one by one, and anode wirings 34 are installed independently of one another in such a way in four pieces per line of anodes 32, and the anodes 32 of each line are connected at every three pieces. Five grid electrodes 24 are selected at each time and the accelerating voltage is impressed while they are shifted one by one, and a positive voltage is impressed on the two central rows of phosphor layers 12 among the four rows pinched by them, and thereby the phosphor layers 12 in each row make light emission one by one. Accordingly two or three effective grid electrodes 24 exist on the left and right of the phosphor layer 12 to make light emission, so that the negative electric field formed by the ambient grid electrodes 24 is canceled in good workmanship, which should suppress the shade of the phosphor layer 12 favorably, and it is possible to generate a light emission with a high brightness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a fluorescent display tube and a driving method thereof.

[0002]

2. Description of the Related Art A phosphor layer is fixed on a plurality of anodes provided on a display surface of a substrate, and thermoelectrons generated from a cathode provided above the phosphor layer in a vacuum space are separated from the phosphor layer and the cathode. There is known a fluorescent display tube of a type in which a phosphor layer is excited by emitting light by being selectively incident on the phosphor layer by being controlled by a control electrode (grid electrode) provided therebetween. Such a fluorescent display tube has a low operating voltage because a phosphor layer to which thermionic electrons generated from the cathode collide is provided near the cathode, and displays clearly. The color display becomes possible by preparing the above phosphor. For this reason, it is widely used as a display component for audio equipment, display panels for automobiles and aircraft, and the like. In particular, in a rib-grid structure fluorescent display tube in which a grid electrode is formed of a conductive film fixed to the top of a rib-like wall protruding higher than the periphery of the phosphor layer, a mesh covering the phosphor layer is provided. Since a grid-shaped grid electrode is not used, display defects such as uneven brightness and short-circuit caused by thermal deformation of the grid electrode when the grid electrode is enlarged along with the enlargement of the display pattern of the phosphor layer are eliminated, and the grid electrode is eliminated. There is such an advantage that the decrease in the luminance of the fluorescent display tube due to the aperture ratio is eliminated.

[0003]

By the way, a plurality of phosphor layers for forming a dot-shaped pixel are crossed on a substrate in a first direction (for example, a row direction) and a second direction (for example, a column direction). The fluorescent display tubes for graphic display lined up along a line are designed to display efficiently and beautifully.
It is driven by a multi-matrix method or the like. In such a driving method, the applicant of the present application has previously proposed a driving method that suppresses the occurrence of partial shading that occurs when one grid electrode is provided for two rows of phosphor layers. For example, as described in Japanese Patent Application Laid-Open No. H10-105118, there is a driving method of a fluorescent display tube in which supplementary light emission is performed in addition to main light emission only in a row where the shade occurs to compensate for the shadow.

In the above-described driving method, when two rows emit light at the same time, only one of the phosphor layers emits a shadow, and only one of them emits auxiliary light. Therefore, in order to obtain a light emission display without unevenness on the entire surface of the fluorescent display tube, the light emission amount obtained by combining the main light emission and the auxiliary light emission in one column coincides with the light emission amount in the other unnecessary column of the auxiliary light emission. Therefore, it is necessary to appropriately control the intensity of the auxiliary light emission according to the degree of the shade. The above means that the auxiliary emission must be controlled separately from the main emission, since the appropriate intensity of the auxiliary emission is usually weaker than the main emission. However, in an ordinary fluorescent display tube, the outputs of a plurality of grid electrodes and a plurality of anode wires are mixed and shared by one drive driver, so that an independent drive driver is required for each anode wire. The driving method of (1) has a problem that the size of the fluorescent display tube (display tube module) including the control device is significantly increased and the manufacturing cost is significantly increased.

A pulse corresponding to one main light emission is represented by n
If the data is divided into pieces and the data is rewritten n times during one main light emission, the pulse width of the auxiliary light emission can be adjusted in 1 / n steps without preparing a drive driver individually. However, in this case, the number of pulses in one cycle, which is originally required for the number of digits, becomes n times, and thus there is a problem that an extremely high processing speed performance is required for the CPU and the driver. When the number of digits is very large (for example, about 256 digits), dividing one pulse into n may cause the processing speed of the CPU or the like to be insufficient. In this case, even if you try to lengthen one cycle according to the processing speed, the length is 20 (m
sec) or less (ie, about 50 (Hz) or more), the upper limit of the number of divisions is low, and the practicality of adjusting the luminance by pulse division is not sufficient.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a rib-grid structure fluorescent display tube capable of obtaining light emission without shadow by a simple control and its driving. It is to provide a method.

[0007]

In order to achieve the above object, the gist of the fluorescent display tube of the first invention is that a phosphor layer for forming a dot-shaped pixel is provided on the surface of each of the phosphor layers. A plurality of anodes that are fixed and are arranged in a first direction and a second direction that intersect with each other on the substrate, and the electrons generated from a cathode that is installed above the anode in a vacuum space are incident on the substrate. A fluorescent display tube of a type that selectively emits light from a phosphor layer, wherein (a)
A rib-shaped wall protruding higher than the phosphor layer between the plurality of anodes, and (b) passing between rows of a plurality of anodes each arranged along the first direction, A plurality of control electrodes provided on the top of the rib-like wall electrically independently of each other; and (c) a second control electrode of the plurality of anodes.
A plurality of lines are connected in a predetermined number at intervals of a predetermined number, and a number corresponding to the predetermined number is provided independently for each row of the anodes in the second direction. And anode wiring.

[0008]

According to a second aspect of the present invention, there is provided a driving method of a fluorescent display tube according to the first aspect. (A) While changing a group of a predetermined number of adjacent control electrodes among the plurality of control electrodes one by one along the second direction, simultaneously applying an acceleration voltage to the group of control electrodes. A scanning step of applying and sequentially scanning, and (b) a predetermined number of rows located at the center in the second direction among the rows of anodes sandwiched by the group of control electrodes in synchronization with the timing of the scanning. Applying a driving voltage to the anode wiring to which a predetermined anode is connected.

[0009]

In this manner, the control electrodes of the fluorescent display tube are electrically independent from each other by passing through a row of a plurality of anodes, that is, an array of anodes arranged in the first direction. And the anode wiring is electrically connected to each other for each row of the plurality of anodes, that is, for each array of anodes arranged in a second direction intersecting the first direction. And the anodes of each row are connected every predetermined number. Therefore, since a plurality of control electrodes can be selected independently of each other, it is possible to provide control electrodes that effectively act on each column of the anode under uniform conditions. Therefore, in the scanning process,
Along with simultaneously applying an acceleration voltage to a group of control electrodes adjacent to each other (a predetermined number), in the driving voltage application step, the row of anodes sandwiched between the group of control electrodes to which the acceleration voltage has been applied is selected. By applying a driving voltage to the anode wiring to which a predetermined anode in one or more columns located at the center is connected, the phosphor layer on the predetermined anode can selectively emit light.

At this time, since the range of the group of control electrodes to which the acceleration voltage is applied is changed one by one along the second direction, the driving voltage is applied to each of the plurality of anodes located at the center of the group. Is applied, the number of control electrodes to which the accelerating voltage is applied becomes uniform on both sides of each of the anode rows, and becomes uniform among the plurality of rows. That is, when the predetermined number of rows (rows of anodes to which a drive voltage is applied for each group of control electrodes) is one row, the number of control electrodes to which the acceleration voltage is applied is the same on the left and right sides of the row. Even if the range of the group changes, the positional relationship between the row of anodes to which the driving voltage is applied and the control electrode to which the accelerating voltage is applied is maintained in the same state. Even when a voltage is applied, an acceleration voltage is applied to a uniform number of control electrodes on both sides thereof. On the other hand, when the predetermined number of rows is a plurality of rows (n rows), the number of control electrodes to which the acceleration voltage is simultaneously applied cannot be equal to each other on each side of the anode on one side and the other side, In addition, the number of the anode rows is different from each other, but also in this case,
Since the range of the group is changed one by one, the rows of each anode take the same number of times while sequentially taking a certain positional relationship with the control electrode according to the position within the range of the group.
The driving voltage is applied only (n times). Therefore, the electric conditions when the drive voltage is applied to each column of the anode can be considered as a superposition of the drive voltage application conditions a plurality of times. Become uniform. In other words, the positional relationship between the row of anodes to which the drive voltage is applied and the control electrode to which the acceleration voltage is applied becomes uniform over time for a plurality of rows of anodes. As described above, since uniform electric conditions can be obtained for each row of the anodes without changing the driving pulse, it is possible to obtain light emission having no shading and uniform intensity on the display surface by simple control. Become. In the present application, “a predetermined number of rows located at the center in the second direction among the rows of anodes sandwiched by the group of control electrodes” is not limited to a part of the sandwiched anode rows, and is not limited to a part of the sandwiched anode rows. It includes everything that exists.

[0011]

In another preferred embodiment of the present invention, the fluorescent display tube preferably includes: (d) a group of a predetermined number of control electrodes adjacent to each other in the plurality of control electrodes in the second direction. A control electrode driving device for simultaneously applying an accelerating voltage to the group of control electrodes to sequentially scan while changing one by one along (e), and (e) synchronizing with the timing of the scan, An anode driving device for applying a driving voltage to the anode wiring to which a predetermined anode in a predetermined column located in the center in the second direction among the rows of anodes sandwiched between the control electrodes is connected. It includes a drive control device. With this configuration, the driving method according to the second aspect of the present invention can be suitably performed.

Preferably, the number of anode wirings provided for each row of the anode is three or more. With this configuration, three or more consecutive rows of anodes are connected to mutually different wirings, so that the drive voltage is independently applied to the multiplex.
Since it is configured in a (triple or more) matrix structure, it is possible to simultaneously apply an acceleration voltage to three or more consecutive control electrodes and simultaneously apply a drive voltage to two or more anode columns without leakage light emission. . Therefore, the luminance can be increased without increasing the drive duty ratio.

Preferably, in the above driving method, the scanning step includes at least two control electrodes to which an accelerating voltage is applied to each of one side and the other side of a row of anodes to which a driving voltage is applied. The predetermined number of control electrodes constituting the group is determined so as to be arranged one by one. In this way, the influence of the negative electric field formed by the other control electrode to which the cutoff bias is applied can be suitably eliminated, and light emission without shadow can be obtained. By the way, an acceleration voltage was applied to sufficiently eliminate the negative electric field formed by the other control electrodes to which the cut-off bias voltage was applied around the group of control electrodes from affecting the columns to emit light. Preferably, two or more control electrodes are provided.

Preferably, in the above driving method, the number of anode wirings provided for each row of the anode is four, and the predetermined number of control electrodes constituting the group is five, The predetermined number of columns is two. In this way, an acceleration voltage is simultaneously applied to five or more continuous control electrodes, and two or three acceleration voltages are always applied to both sides of two rows of anodes within the group. Control electrodes are arranged. Therefore, since two or more control electrodes to which the acceleration voltage is applied are provided for any of the anodes to which the drive voltage is applied, the shade of light emission at the outer ends of the two rows of anodes is suitably suppressed. . Therefore, uniform light emission with higher luminance and no unevenness can be obtained.

[0015]

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

FIG. 1 shows a fluorescent display tube 1 according to one embodiment of the present invention.
FIG. 1 is a perspective view showing the entirety of a part 0 with a part thereof cut away.
In the figure, a fluorescent display tube 10 is made of, for example, a substrate 14 made of an insulating material such as glass, ceramics, or enamel provided with a phosphor layer 12 having a large number of dot patterns on one surface, and a glass formed in a frame shape. , A transparent cover / glass plate 18, and a plurality of anode terminals 20 _P ,
A grid terminal 20 _G and a cathode terminal 20 _K are provided, and the substrate 14, the spacer 16, and the cover glass plate 18 are mutually glass-sealed,
A vacuum space surrounded by these members is formed.

The one surface 22 of the substrate 14 covered by the vacuum space functions as a display surface of the fluorescent display tube 10. The plurality of dot-shaped phosphor layers 12 on the display surface 22 have polygonal shapes similar to each other, for example, each side along the longitudinal direction of the substrate 14 and the width direction substantially orthogonal to the same. (μm), and are provided at a constant center interval in these two directions. Further, a plurality of grid electrodes 24 having the same shape are formed on the display surface 22 so as to form a lattice shape. Each of the phosphor layers 12 has substantially the entire circumference formed by the grid electrode 24. being surrounded. Each of the plurality of grid electrodes 24 has a longitudinal shape extending along the short side direction of the substrate 14 and passes between a plurality of phosphor layers 12 arranged in the longitudinal direction of the substrate 14. That is, the grid electrode 24 is provided between the rows of the plurality of phosphor layers 12 arranged along the short side direction of the substrate 14, and the electrodes passing between the rows are electrically independent from each other. It is connected to the grid terminal 20 _G and. In this embodiment, the short side direction of the substrate 14 corresponds to the first direction, and the longitudinal direction corresponds to the second direction, and the two directions are orthogonal to each other. In the present embodiment, the grid electrode 24 corresponds to a control electrode.

[0018] On both ends of the substrate 14, the cathode terminal 20 of the pair having a _K filament support frame 26 (shown only one located on the right side in the drawing)
Are fixedly provided, and a plurality of thin filaments (filaments) functioning as a directly heated cathode (cathode) are provided between the filament supporting frames 26.
A cathode (cathode) 28 is stretched so as to be parallel to the longitudinal direction of the substrate 14 and at a predetermined height away from the display surface 22. The fluorescent display tube 10 is provided with an exhaust hole for evacuating and sealing the inside of the vacuum vessel, a getter for maintaining the degree of vacuum inside after sealing, and the like.
These have been omitted.

FIG. 2 is an enlarged perspective view showing a part of the display surface 22 of the substrate 14. As shown in the figure,
On the display surface 22, a rib-like wall 3 having a lattice shape as a whole
Numeral 0 protrudes in a state of contacting and surrounding the outer peripheral edge of the phosphor layer 12. That is, they are erected in a direction away from the substrate 14, that is, in a direction toward the filament 28 side. The rib-like wall 30 is made of, for example, an insulating material such as low-melting glass containing an inorganic filler such as alumina particles, and has a width dimension of, for example, about 60 to 150 (μm), and Is formed at a height higher than the surface of, for example, about 60 to 300 (μm). The grid electrode 2
Reference numeral 4 denotes a thick-film conductor mainly composed of a particulate conductive material such as particulate graphite, silver, palladium, copper, aluminum, nickel, and the like.
It is provided with a thickness of about 0 (μm), for example, about 20 (μm). That is, in the present embodiment, the control electrode is provided in a rib-grid structure in which the grid electrode 24 is provided on the top of the rib-shaped wall 30. For this reason, the grid electrode 24 is formed on the phosphor layer 12 by the rib-shaped wall 30.
Insulated from.

As shown in FIG. 2, each of the plurality of grid electrodes 24 has one elongated portion 24y extending in the width direction of the substrate 14 and a plurality of grid electrodes 24y. A plurality of branch portions 24x extending in a direction parallel to each other along the longitudinal direction of the substrate orthogonal to the intermediate portion.
Consisting of The plurality of branch portions 24x are provided at a plurality of locations having a constant center interval in the longitudinal direction of the longitudinal portion 24y and protrude from the longitudinal portion 24y on both sides in the width direction by the same length. That is, the grid electrode 24 has a symmetrical shape with respect to the center line of the longitudinal portion 24y. Note that the branch portions 24x are provided at the same position in the width direction of the substrate 14 in any grid electrode 24, and the center interval in the width direction is the same as the center interval of the phosphor layer 12. However, the branch portions 24x, 24x protruding in the direction approaching each other in the grid electrodes 24, 24 adjacent to each other have their tips separated from each other by a slight size of, for example, d _G = 100 (μm). The electrical independence between the grid electrodes 24 is ensured by the gap.

For this reason, each of the phosphor layers 12 is
4, more specifically, its entire periphery is surrounded by the two grid electrodes 24 located on both sides thereof, and more specifically, by its longitudinal portion 24y and branch portion 24x, but the manner of enclosing is not sufficient. Is complete. In addition, the branch part 24x
The length of one side of the phosphor layer 12 is 400 (μ).
m), if the size of the gap is 100 (μm), it is about 150 (μm). Further, since the phosphor layer 12 is provided in close contact with the inner peripheral edge thereof in a region surrounded by the grid electrode 24, the mutual distance d _A between the phosphor layers 12 is equal to the longitudinal portion of the grid electrode 24. The width is equal to the width of the branch 24x and the branch 24x, for example, about 60 to 150 (μm). The planar shape of the rib-like wall 30 is the same as the planar shape of the grid electrode 24, for example, as shown in FIG.
And a branch 30b.

As shown partially in FIG. 2, a plurality of anodes 32 each having a substantially rectangular shape are provided below the phosphor layer 12 on the display surface 22. I have. The anode 32 is made of, for example, a graphite layer having a thickness of about 30 to 40 (μm). The plurality of phosphor layers 12 are respectively fixed on the anodes 32, and the length of each side of the anodes 32 is about 400 (μm), that is, substantially the same size and size as the phosphor layers 12. It has a shape. The rib-shaped walls 30 are projected from each other between the anodes 32. The anodes 32 are separated from each other on the substrate 14 by the rib-shaped walls 30, so that each is independent, that is, mutually electrically connected. Insulated.

The phosphor layer 12 has one or several kinds of phosphors corresponding to a desired emission color provided for each anode 32, and the thickness dimension is determined for each emission color. For example, it is about 30 (μm). When a plurality of types of phosphors are used, for example, in a color display using three colors of RGB, for example, the RGB
The phosphor layers 12 corresponding to the three colors B are provided and arranged in a stripe arrangement, or 4 rows of 2 rows × 2 columns adjacent to each other are arranged.
Phosphor layers 12 corresponding to the four colors of RGB are provided for each unit to form a quartet arrangement. One pixel of the fluorescent display tube 10 has three or four light emitting colors different from each other arranged in a stripe shape or a rectangular shape adjacent to each other (however, in the case of four, two light colors are the same). It is constituted by the phosphor layer 12.

FIG. 3 is a view for explaining the electrode structure on the substrate 14 in a cross section taken along the line III-III in FIG. 2, that is, in a cross section at an arbitrary position in the longitudinal direction of the substrate 14. On the display surface 22 of the substrate 14, a thick film conductor paste is printed and baked to a thickness of about 15 (μm) by a screen printing method or the like, or by vapor deposition and etching of an aluminum thin film or the like. A plurality of anode wires 34 are formed so as to be connected to the anode terminals _20P , respectively. On the anode wiring 34, an insulator layer 38 formed to a predetermined thickness so as to cover substantially the entire display surface 22 and appropriately provided with a through hole 36 penetrating in the thickness direction is fixed. The insulator layer 38 is formed, for example, by applying a thick film insulating paste composed of a low-melting glass and a coloring pigment to a thickness of about 30 to 40 (μm) by a screen printing method and firing it. .

The anode 32 is provided on the insulator layer 38 at a position where the anode 32 is electrically connected to the anode wiring 34 through the through hole 36. The anode 32 is formed by printing and firing a thick film printing paste containing graphite as a main component in a predetermined dot pattern. The phosphor layer 12 is formed by printing a thick-film phosphor paste on the anode 32. The rib-like wall 30 is formed by printing a thick film insulating paste around the phosphor layer 12 and the anode 32. That is, it is not provided directly on the substrate 14 but on the insulator layer 38. The rib-shaped wall 30 is formed by repeatedly printing a thick-film insulating paste made of an insulating material such as a low-melting glass or an inorganic filler in a predetermined pattern having a line width of about 60 to 150 (μm), for example, to form a laminate. Insulator layer 3
The height is about 60 to 300 (μm), for example, about 200 (μm) from the eight surfaces, and about 30 to 250 (μm) from the surface of the phosphor layer 12. The grid electrode 24 has silver, palladium, aluminum,
It is formed by printing a thick film conductor paste containing a particulate conductive material such as nickel or carbon with a thickness of about 5 to 50 (μm).

The plurality of anode wirings 34 are provided, for example, along the longitudinal direction of the substrate 14, respectively.
Anodes 34 are connected to different anode lines 34 in units of rows along the longitudinal direction of the substrate 14 so that those substantially aligned in the width direction are electrically independent of each other. FIG. 4 schematically shows the connection state of the first row of the uppermost anode 32 in the drawing. In FIG. 4, the anode wiring 34 has four independent lines a to d for each row of the anode 32, for example, 34-1a, 34-1b, and 34-1 for the first row.
c, 34-1d are provided, and a plurality of anodes 32 in each row are connected to a common one of the four anode wirings 34 every three. That is, in the present embodiment, the substrate 14 is configured to have an anode quadruple wiring structure, and the anode 32 connected to any one of the four anode wirings 34 has a constant spacing in the longitudinal direction of the substrate 14. In line. The connection state with the anode wiring 34 is the same for any other rows of the anodes 32 not shown.
In FIG. 4, for convenience of illustration, the anode 32 and the grid electrode 24 are drawn so as not to be in contact with each other.

In FIG. 4 described above, the fluorescent display tube 1
0 is provided with a control circuit connected via a terminal 20 or integrally formed on the substrate 14. Each of the plurality of grid electrodes 24 is connected to a grid driver via a grid wiring (not shown). 40 output ports are independently connected. Also, the anode 32 of each row is 3
Four anode wirings 34 provided in every other connected row are independently connected to the output ports of the anode driver 42, respectively. The grid driver 40 and the anode driver 42 are controlled in accordance with output signals of a controller 44, respectively, and are driven in accordance with data input to the controller 44 as described later. In this embodiment,
The grid driver 40 corresponds to a control electrode driving device, and the anode driver 42 corresponds to an anode driving device.
The controller 44 includes a ROM, a RAM, a CPU,
It comprises an I / O, a converter and the like.

When driving the fluorescent display tube 10 configured as described above, a plurality of grid electrodes 24 are formed as one set while a predetermined heat current is constantly applied to the plurality of filaments 28. (For example, the details will be described later.)
Scanning is performed by sequentially applying a relatively positive acceleration voltage of about (V). Then, in synchronization with the scanning timing, a drive voltage of, for example, about 20 (V) that is positive with respect to the cathode potential is applied to a desired anode wiring 34. Thereby, the filament 28
Are accelerated by the grid electrode 24 to which a positive voltage is applied. Therefore, when a positive voltage is also applied to the phosphor layer 12 surrounded by the grid electrode 24 through the anode 32, the phosphor electrons Electrons enter the layer 12 to excite and emit light. However, even if a positive voltage is applied to the phosphor layer 12, if a negative cutoff bias of about several (V) is applied to the filament 28 to the grid electrode 24 surrounding the phosphor layer 12, thermions are generated. The phosphor layer 12 does not reach the phosphor layer 12 and does not emit light. Therefore, in a state where the thermoelectrons are emitted by the current flowing through the filament 28, the desired one of the phosphor layers 12 is synchronized with the timing at which the accelerating voltage is sequentially applied to the grid electrode 24. When a positive voltage is applied, light emission display is performed in a desired pattern by so-called dynamic driving.

Hereinafter, the grid electrode 24 and the anode wiring 3
FIG. 5 showing the drive voltage waveform to the grid electrode 4, the voltage application state to the grid electrode 24 at a specific time, and the phosphor layer 1
The driving method of the fluorescent display tube 10, that is, the control of the controller 44 will be described in detail with reference to FIGS. In addition, in FIG.
Gi, Gj, ~ Gn ... "represent grid electrodes 24 sequentially arranged in the row direction, and" ... Ara, Arb, ~ A
“sb...” represent four anode wires a, b, c, and d provided in “... r rows, s rows,. 6 (a) to 6 (c), "I, J,...
"O" represents a column of the phosphor layer 12, "r, s, ..." represents a row of the phosphor layer 12, and "a, b, c, d" written in squares are: This shows the distinction between the four anode wirings 34 to which the anodes 32 under the phosphor layers 12 in each row are connected. Further, “「 ”indicates that an acceleration voltage is applied to the grid electrode 24, and“ 「” indicates that a cutoff bias is applied.

At time t1, an acceleration voltage is applied to five of the grid electrodes Gi to Gm among the grid electrodes 24, and
Positive voltage is applied to Ara, Arb, Asa, Asb, etc. of the anode wiring 34, that is, two of the four lines in each row with the subscripts a and b. Therefore, the electrons generated from the filament 28 are attracted to the grid electrodes 24 to which the accelerating voltage is applied. Of the rows of the phosphor layer 12 adjacent to the grid electrodes 24, the rows I, L, M and I Since a positive voltage is not applied to one row (not shown) connected to the anode wiring 34 with a subscript c on the left side, electrons are not directed to the four rows of phosphor layers 12 and light is emitted. Absent. On the other hand, since a positive voltage is applied to the columns J and K, the attracted electrons are directed to the phosphor layers 12, and the phosphors are excited and emitted by the incident electrons. In FIG. 6B, at time t1
, The phosphor layer 12 emitting light is shown in white.
In this figure, the hatched phosphor layer 12 does not emit light because no positive voltage is applied. The phosphor layer 12 marked with a cross does not emit light because it is surrounded by the grid electrodes Gn, Go, and Gp to which a positive voltage is applied, but to which a cutoff bias is applied.

That is, at the time t1, the accelerating voltage is applied to the five grid electrodes 24 at the same time, so that J, located at the center in the row direction among the columns of the phosphor layer 12 sandwiched therebetween. Two columns of K are selected as columns to emit light, and a positive voltage is applied only to the phosphor layer 12 of a row to emit light according to input data among the two columns. Therefore, of the two anode wirings a and b in each row, the one to which a positive voltage is actually applied is only the one connected to the phosphor layer 12 for emitting light in the columns J and K. The waveform in the column of the anode wiring in FIG. 5 indicates that a positive voltage is applied or a cutoff bias is applied according to data.

At time t2, a cutoff bias is applied to the grid electrode Gi, an acceleration voltage is applied to the grid electrode Gn, and the anode wirings Arb, A
A positive voltage is applied to rc, Asb, etc., that is, two of the four subscripts b and c of each row. Therefore, during the period from time t2 to time t3, of the four rows of phosphor layers 12 of J, K, L, and M sandwiched between the grid electrodes 24 to which the acceleration voltage is applied, K located at the center of the phosphor layers 12 is arranged. , L are selected as columns to emit light, and among the phosphor layers 12 in that column, predetermined ones corresponding to data are emitted. FIG.
(c) shows the selected state of the grid electrode 24 and the light emitting state of the phosphor layer 12 at this stage.

At time t3, an acceleration voltage is similarly applied to the grid electrodes Gk to Go, and
By applying a positive voltage to the anode wirings Arc, Ard, etc., that is, two of the four subscripts in each row, the subscripts c and d,
The phosphor layers 12 in two rows of L and M emit light. Time t
In No. 4, an acceleration voltage is applied to the grid electrodes Gl to Gp, and a positive voltage is applied to the anode wires Ara, Ard, Asa, and the like, so that the phosphor layers 12 in two rows of M and N emit light.

As described above, in this embodiment, five grid electrodes 24 continuous in the row direction are grouped, and the range is changed one by one in the row direction, and the grid electrodes 24 forming the group are changed. At the same time, the acceleration voltage is applied while the selection range is shifted one by one by selecting five grid electrodes 24 and the grid electrodes 24 are sandwiched between the grid electrodes 24 to which the acceleration voltages are applied. By applying a positive voltage to the anode wiring 34 to which predetermined ones of two columns located in the center in the row direction among the columns of the phosphor layers 12 (anodes 32) are connected, the phosphor layers 12 Are sequentially emitted. In the fluorescent display tube 10 of the present embodiment, the grid electrode 24 is constituted by a plurality of linear electrodes that are electrically independent from each other and pass between rows of the plurality of anodes 32, respectively.
Since four anode wirings 34 are provided electrically independently of each other for each row of a plurality of anodes 32 and every third anode 32 of each row is connected, a plurality of grid electrodes 24 can be selected independently of each other.
The grid electrodes 24 that effectively act on each of the two columns can be provided under uniform conditions. Therefore,
An acceleration voltage is simultaneously applied to a group of five grid electrodes 24 adjacent to each other, and the group of grid electrodes 2
4 located at the center of the row of the anode 32 sandwiched between
By applying a positive voltage to the anode wiring 34 to which a predetermined anode 32 in the column is connected, the phosphor layer 12 on the predetermined anode 32 can selectively emit light. In this embodiment, the step of simultaneously applying the accelerating voltage to the five grid electrodes 24 and sequentially scanning as described above corresponds to the “scanning step”, in which the anode wiring 34 corresponding to the selected grid electrode 24 is directly scanned. The step of applying a voltage corresponds to the “step of applying a drive voltage”, respectively.

At this time, the range of the group constituted by the five grid electrodes 24 is shifted one by one, and the rows of the phosphor layers 12 to emit light are selected two rows at a time and scanned by being shifted one row at a time. Therefore, two or three grid electrodes 24 to which the accelerating voltage is applied are always present on the left and right sides of the row of the phosphor layers 12 that emit light. Therefore, the number of the grid electrodes 24 to which the accelerating voltage is applied is a number sufficient to eliminate the negative electric field formed by the grid electrode 24 to which the cutoff bias is applied around the phosphor layer 12 to emit light. Since the number is kept at two or more, the shade of the phosphor layer 12 due to the negative electric field is suitably suppressed, and light emission of high luminance is obtained.

The number of grid electrodes 24 to which the accelerating voltage has been applied is two in the selected two rows of phosphor layers 12 in one row located on the left side in FIG.
The number of books is three on the right side, while the other row on the right side has three opposite numbers, three on the left side and two on the right side. Therefore, in the driving method of the present embodiment, the electrical conditions of the phosphor layers 12 in the two rows that emit light at each time cannot be uniform both in the rows and on the left and right sides of each row. However, when the electrical conditions in the two light emissions are superimposed on each column, the conditions in each column are substantially equal on the left and right with time and substantially uniform between the columns, so that the surface of each phosphor layer 12 Uniform light emission is obtained. For this reason, uniform light emission can be obtained with a drive waveform having a constant pulse width for the five grid electrodes 24 and the two rows of phosphor layers 12, so that the row of anodes can be changed without changing the applied drive pulse. A uniform electric condition is obtained every time, and it is possible to obtain light emission with no shading and uniform intensity on the display surface by simple control. That is, in the present embodiment, the phosphor layers 12 to emit light are selected by two columns and are shifted (shifted) by one column. Therefore, compared to the driving of emitting light by two columns and shifting the selection range by two columns. The grid electrodes 2 on the left and right of each row of the phosphor layer 12
The electric field formed by 4 becomes substantially uniform, and the shade becomes inconspicuous.

For example, looking at time t1, two columns are located on the left side and three columns are located on the right side of the J column located on the left side, while three columns are located on the left side and three columns on the right side of the K column located on the right side. It becomes two. Since this relationship is always maintained, looking at time t2 when the K column is on the left side, two lines on the left side for the K column,
There are three on the right, three on the left and two on the right for row L.
It becomes a book. Therefore, in the first light emission of the two light emissions in each column, the number of light beams on the left side is smaller than the number of light beams on the right side. The luminance tends to decrease from the right end to the left end (or the luminance at the left end tends to decrease slightly), but in the second light emission, the opposite positional relationship results in the phosphor layer 12 moving from the left end to the right end. The luminance may tend to decrease (or the luminance at the right end tends to decrease slightly) as it goes. Therefore, the illusion and uneven brightness due to the difference in the influence of the negative electric field are reduced in each phosphor layer 1.
Even if it occurs every single light emission in 2, the light emission is canceled out by the two light emissions, so that the luminance in each plane of the phosphor layer 12 becomes uniform.

While the embodiment of the present invention has been described in detail with reference to the drawings, the present invention can be embodied in still another embodiment.

For example, in the fluorescent display tube 10 of the embodiment, four anode wires 34 are provided in each row.
The number thereof can be appropriately changed according to the number of columns of the phosphor layers 12 to emit light at the same time, the number of grid electrodes 24 to which the accelerating voltage is applied at the same time, and the like, and are appropriately determined in a range where a desired driving method can be realized.

Further, in the embodiment, the number of rows to emit light at the same time is two, but the number of rows of the phosphor layer 12 to emit light at each time can be set to one row or three or more rows. For example, in order to sequentially emit light in each column, a double or more anode matrix structure in which two anode wirings 34 are provided in each row may be used. Conversely, three or more columns of phosphor layers 12 may be simultaneously formed. In the case of emitting light, a four-fold or more anode matrix structure may be appropriately adopted. Increasing the number of columns that emit light at a time by increasing the multiplicity of the anode wiring 34 has the advantage that the brightness can be increased while maintaining the cycle time (length of one cycle).

In the embodiment, the acceleration voltage is simultaneously applied to the five grid electrodes 24, and the two rows of phosphor layers 12 located at the center in the range sandwiched between the grid electrodes 24 emit light. At least two grid electrodes 24 to which the accelerating voltage is applied are provided on one side for the columns to be formed, but the number is appropriately changed according to the arrangement of the phosphor layers 12, the driving conditions, and the required display quality. You. In other words, even when it is desired that shading is as small as possible, at least one grid electrode 24 is not always necessary if two effective (that is, an accelerating voltage is applied) grid electrodes 24 are not necessarily required depending on the arrangement and driving conditions. The number of lines forming a group and the number of columns to emit light simultaneously can be selected so that effective grid electrodes 24 exist. In other words, the driving may be such that all the columns surrounded by the effective grid electrodes 24 emit light. Conversely, if three or more effective grid electrodes 24 are required, each of the two
It is sufficient to drive the grid electrode 24 so that only the center excluding the columns emits light, that is, at least six or more are grouped. According to the present invention, since the grid electrodes 24 are all independent, the number of lines to which the acceleration voltage is simultaneously applied can be freely set by the drive circuit.

When a certain degree of shading is allowed, depending on the degree of the shading, the number of grid electrodes 2 is smaller than the number of grid electrodes 2 that can prevent shading of all the columns to be illuminated.
4 may be simultaneously driven. For example, by simultaneously selecting three grid electrodes 24 in a double anode matrix or a triple anode matrix,
It is also possible to change the selection range one by one and to drive the two rows of phosphor layers 12 sandwiched by the three rows of grid electrodes 24 at the same time. In the case of a double anode, a positive voltage is also applied to the row of the phosphor layers 12 adjacent to the outside of the three grid electrodes 24, and the thermoelectrons directed to the phosphor layers 12 are applied to this. In the case where it is obstructed by the negative electric field formed by the adjacent grid electrodes 24 to which the cutoff bias is applied, electrons are present only in two rows sandwiched by the three grid electrodes 24 to which the acceleration voltage is applied. In such a case, a double anode structure is sufficient as it is oriented.

In the embodiment, since the two rows of phosphor layers 12 emit light simultaneously, it is not possible to secure the symmetry of the arrangement of the grid electrodes 24 at each light emission, so that each row emits light twice. However, when only one column emits light at a time, the symmetry of the arrangement of the grid electrodes 24 can be always maintained, so that the number of times of light emission in each column may be one. Also,
In order to simultaneously emit light in two or more rows, even if the acceleration voltage cannot secure the symmetry of the grid electrode 24, the difference in luminance between the left and right sides of the phosphor layer 12 due to the asymmetry is small enough to be ignored. In this case, the number of times of light emission in one cycle may be one, regardless of the number of columns that emit light at the same time. The smaller the number of times of light emission in one cycle, the more C
Since the load on the PU is reduced and it is preferable for driving, the number of columns to emit light at the same time and the number of times of light emission in one cycle are determined in consideration of required display quality and cost.

In the embodiment, each row is caused to emit light twice in order to suppress shading as much as possible.
When the number of effective grid electrodes 24 is sufficiently large for a column to emit light, for example, a driving condition such that three or more effective grid electrodes 24 are present on both sides of any phosphor layer 12 In this case, the number of light emission of each column in one cycle may be set to one. In addition, when the influence of the negative electric field formed by the other grid electrode 24 adjacent to the grid electrode 24 to which the acceleration voltage is applied is sufficiently small, for example, the cutoff potential is low and the intensity of the negative electric field itself is reduced. When the dot size is sufficiently small, or when the dot size of the phosphor layer 12 is sufficiently large and the grid electrodes 24 are sufficiently separated, one light emission is sufficient.

In the embodiment, the phosphor layer 12 emits light in two rows and each row emits light twice. However, the phosphor layer 12 emits light in three rows and each row emits light three times. A driving method and a driving method in which light emission is performed four rows at a time and light emission is performed twice or more in each row can be appropriately adopted according to required display quality and a substrate structure. For example,
By shifting the four grid electrodes 24 one by one as a group and simultaneously emitting light from the three rows of phosphor layers 12 sandwiched between them as a structure of four or more anode matrices, the uniformity of light emission in each row is improved. The number of times of light emission can be set to three while maintaining the same.

In the embodiment, the case where the present invention is applied to the fluorescent display tube 10 in which a plurality of square phosphor layers 12 are arranged in two directions orthogonal to each other has been described. The present invention is similarly applied to a case where hexagonal phosphor layers are closely arranged, that is, a fluorescent display tube in which the first direction is not orthogonal to the second direction.

Although not specifically exemplified, the present invention can be variously modified without departing from the gist thereof.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing a fluorescent display tube according to an embodiment of the present invention.

FIG. 2 is an enlarged perspective view showing a part of a display surface.

FIG. 3 is a diagram illustrating a structure of a substrate in a cross section taken along line III-III in FIG. 2;

FIG. 4 is a diagram illustrating a main part of a control configuration of the fluorescent display tube of FIG. 1;

FIG. 5 is a driving waveform diagram illustrating an example of a driving method of the fluorescent display tube of FIG. 1;

6 (a) and 6 (b) are diagrams illustrating voltage application and light emission at a specific time in FIG.

[Explanation of symbols]

 10: Fluorescent display tube 12: Phosphor layer 14: Substrate 24: Grid electrode (control electrode) 32: Anode 34: Anode wiring 40: Grid driver 42: Anode driver

Continued on the front page (72) Inventor Jun Mohri 2160, Yatsunami, Yasu-cho, Asakura-gun, Fukuoka No. 2160 Noritake Electronics Industry Co., Ltd. Yasu Plant F-term (reference) 5C036 EE04 EF02 EF06 EG15 EG28 EG29 EG48 EH04 EH26

Claims (4)

[Claims] 1. A phosphor layer for forming a dot-shaped pixel is fixed to a surface thereof, and a plurality of anodes are arranged on a substrate in a first direction and a second direction crossing each other. A fluorescent display tube of a type in which electrons generated from a cathode erected above the inside of a vacuum space are made to selectively emit light by the phosphor layer, wherein the fluorescent material is provided between the plurality of anodes. A rib-shaped wall protruding higher than the body layer; and a rib-shaped wall of the plurality of anodes arranged in the first direction, passing through each other and electrically independent of each other. A plurality of control electrodes provided on the top, and a plurality of anodes arranged in the second direction among the plurality of anodes are connected at predetermined intervals, and for each anode row along the second direction. The number corresponding to the predetermined number is mutually A fluorescent display tube comprising: a plurality of anode wirings which are provided independently independently of each other. 2. An accelerating voltage is simultaneously applied to the group of control electrodes while changing a group of a predetermined number adjacent to each other among the plurality of control electrodes one by one along the second direction. And a control electrode driving device for sequentially scanning by applying a predetermined voltage. A predetermined electrode positioned at the center in the second direction in the row of anodes sandwiched by the group of control electrodes in synchronization with the timing of the scanning. The fluorescent display tube according to claim 1, further comprising a drive control device including: an anode drive device for applying a drive voltage to the anode wiring to which a predetermined anode in the column is connected. 3. The method of driving a fluorescent display tube according to claim 1, wherein a group of a predetermined number of the plurality of control electrodes adjacent to each other is formed along the second direction. A scanning step of applying an accelerating voltage to the group of control electrodes at the same time and sequentially scanning while sequentially changing the rows, and a row of anodes sandwiched between the group of control electrodes in synchronization with the scanning timing. Applying a driving voltage to the anode wiring to which a predetermined anode in a predetermined number of columns located at the center in the second direction is connected. 4. The number of anode wirings provided for each row of the anode is four, the predetermined number of control electrodes constituting the group is five, and the predetermined number of columns is two columns. A method for driving a fluorescent display tube according to claim 3.