JP2002298769A - Fluorescent display tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorescent character display tube capable of making multi-color displaying without involving a drop of the grade originating from dislocation of phosphor pieces from one another or causing an increase in the man-hours. SOLUTION: On the whole surface approximately of one anode 54 having a rectangular shape viewed on the plan, a phosphor layer A having the same shape and a size some smaller than it is attached fast, and to the surface thereof a plurality of phosphor layers B in circular shape with the installing position fixed is attached fast ion such a way as covering part of the phosphor layer A. The light emission wavelength of the phosphor layer A located under and the light emission wavelength of the phosphor layer B located over have different values, lying in the visible ray range. Because two sorts of phosphor make light emission simultaneously, the color received by the observer's eyes actually will be an intermediate color consisting of a mixture thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an improvement in a fluorescent display tube.

[0002]

2. Description of the Related Art A phosphor layer is fixed on, for example, a plurality of anodes provided on a display surface of a substrate, and thermoelectrons generated from, for example, a cathode provided above the phosphor layer in a vacuum space are incident on the phosphor layer. A fluorescent display tube of a type in which the phosphor layer is excited to emit light by causing the phosphor layer to emit light is known. The electrons are selectively incident on the phosphor layer by being controlled by a control electrode (grid electrode) provided as necessary between the phosphor layer and the cathode. Such a fluorescent display tube has a feature that the operating voltage is low and the display is clear because a phosphor layer to which thermionic electrons generated from the cathode collide is provided near the cathode. for that reason,
It is widely used as a display component of audio equipment, display panels of automobiles and aircraft, and the like.

[0003]

By the way, the display color of the fluorescent display tube can be multicolored by forming a phosphor layer with a plurality of kinds of phosphors having mutually different emission colors (emission wavelengths). Generally, the phosphor layer is formed by applying a phosphor paste using a thick film screen printing method. Therefore, when phosphor layers of a plurality of kinds of emission colors are provided, a different opening pattern is used for each type. It is necessary to prepare a plurality of screens provided with a phosphor paste and sequentially apply the phosphor paste. Therefore, various inconveniences have occurred due to the application step being performed a plurality of times.

[0004] For example, when light-emitting display is performed using characters, symbols, and the like composed of a plurality of colors as one unit of display, FIG.
As shown in FIG. 2, phosphor layers 12 and 14 having mutually different emission colors are provided on one anode 10 constituting one segment. However, such a pattern in which the phosphors are separately applied is formed by applying one and the other of the two-color phosphors with two types of opening patterns as shown in (b) and (c), respectively. If the application position of each phosphor shifts,
A gap is formed between the phosphor layers 12 and 14, or the gaps overlap each other, so that the light emitting area of the lower phosphor layer (for example, 12) is reduced and its shape is changed, thereby deteriorating the display quality. Therefore, this method has been of low utility since relatively coarse coating, which does not affect the display quality due to misregistration, is the limit and fine color coding is not possible.

For display applications such as a spectrum analyzer in which strip-shaped segments 16 are arranged as shown in FIG. 2, it is desired to display gradation (gradation). Conventionally, such gradation display is performed by separately applying phosphors having different emission wavelengths for each segment 16. However, in this method, only the number of gradations equal to the number of phosphors used can be obtained. For this reason, it is difficult to obtain a multi-level gradation display with a high visual effect, and there is a problem that the number of steps is significantly increased when the number of gradations is increased.

As a multicoloring method which does not involve an increase in man-hours, a single segment is divided into sizes in which each light emission cannot be distinguished in consideration of an observation distance at the time of use, and a plurality of types of phosphors are used. There is a type that displays an intermediate color by mixing different types of phosphors by applying different colors. FIG. 3 shows an example in which two types of phosphor layers 18 and 20 are separately applied in a grid shape. Since the luminescent color obtained by the color mixture is determined by the area ratio of the phosphor layers 18 and 20 which are separately applied, by adjusting the area ratio, an extremely large number of luminescent colors can be realized without increasing the types of phosphors. Furthermore, if this is used, the phosphor 1 can be placed between a plurality of segments adjacent to each other.
By changing the area ratio of 8, 20 stepwise, multi-gradation display becomes possible. However, when this method is employed, if the printing positions of the individual phosphors are shifted, gaps or partial overlaps occur between the phosphors, and the phosphor layers 18 and
Since the area ratio of 20 cannot be kept at the expected value, the size of each of the phosphor layers 18 and 20 is estimated to be misaligned.
In other words, it must be formed relatively large (that is, such that printing deviation does not affect display quality). As a result, it was not possible to express so many intermediate colors, and furthermore, it was not possible to make the division sufficiently small with respect to the observation distance, so that the color mixture was insufficient and the desired emission color could not be obtained.

The present invention has been made in view of the above circumstances, and an object of the present invention is to enable multicolor display without deteriorating quality or increasing man-hours due to misalignment between phosphors. An object of the present invention is to provide a fluorescent display tube.

[0008]

In order to achieve the above object, the gist of the present invention is to provide an anode provided on a display surface of a substrate in a predetermined pattern, and a fluorescent lamp fixed to the surface of the anode. A fluorescent layer, wherein the fluorescent layer is excited by emitting electrons generated from a cathode in a vacuum space to emit light by exciting the fluorescent layer, wherein the fluorescent layer comprises (a) the anode A first phosphor layer that generates visible light of a first wavelength fixed to the surface of the first phosphor layer, and (b) a predetermined shape defined so as to cover a part of the first phosphor layer when viewed from a light emission observation direction. And a second wavelength different from the first wavelength.
A second phosphor layer that generates visible light of a wavelength.

[0009]

In this way, the first phosphor layer fixed to the anode surface is partially covered with the second phosphor layer when viewed from the emission observation direction. The portion of the phosphor layer that actually contributes to the display, ie, the substantial light emitting portion, is the remaining portion that is not covered by the second phosphor layer. On the other hand, the light emitting area and the shape of the second phosphor layer are maintained in a predetermined shape without any change by the first phosphor layer. Therefore, even if the second phosphor layer is fixed to be shifted from the preset position and the relative position with respect to the first phosphor layer is changed from the expected relative position, a positional shift that can occur with normal printing accuracy is obtained. Therefore, there is no gap between the first phosphor layer and the second phosphor layer, and
The substantial area of the light emitting portion of the first phosphor layer was maintained at the desired value, and its shape was hardly changed, and the ratio of the light emitting area to the second phosphor layer was maintained at the desired value. It is. Therefore, multicolor display can be performed without deteriorating quality or increasing man-hours due to misalignment between a plurality of types of phosphors.

For example, when one segment of a character, symbol, figure, or the like is formed of a plurality of kinds of phosphors having different emission colors, even if the relative positions of the phosphor layers of the respective emission colors are shifted, The generation of a gap between the phosphor layers and the change in the area and shape of the lower phosphor layer are suitably suppressed. In addition, when one segment is divided into a large number of areas and a plurality of types of phosphor layers are separately applied to display an intermediate color by mixing these colors, even if the relative positions of the plurality of types of phosphor layers are shifted, the mutual positions are not changed. Since the area ratio is maintained at the desired value, the division of the painting can be reduced, so that a desired intermediate color can be reliably obtained even when the viewing distance is relatively short.
For this reason, even in the case of performing gradation display, by setting various area ratios between the first phosphor layer and the second phosphor layer, the number of steps as in the case where phosphor layers of a large number of luminescent colors are painted separately. Multi-tone display can be performed without increasing the number of gray levels.

In the fluorescent display tube, there are two directions for observing the light emission, that is, the front side or the back side of the phosphor fixed on the anode. When observed from the front side, the anode, the first phosphor layer, and the second phosphor layer are sequentially fixed on the substrate, but when observed from the back side, the anode, the first phosphor layer and the second phosphor layer are adhered on the substrate. A structure in which the two phosphor layers and the first phosphor layer are sequentially fixed. Also in the latter case, since the second phosphor layer covers only a part of the first phosphor layer, the rest of the first phosphor layer is directly fixed to the anode. The phrase "fixed to the surface of the anode" in the claims includes such an embodiment.

[0012]

In another preferred embodiment of the present invention, the first phosphor layer and the second phosphor layer preferably have a thickness of 5 to 50 (μm). With this configuration, since both the first phosphor layer and the second phosphor layer are sufficiently thin in a range where a sufficient light emission amount can be secured, light emission at a desired luminance can be achieved for any of the phosphor layers. Or an intermediate color by a desired color mixture can be obtained. If the thickness dimension is less than 5 (μm), since the phosphor particles are loosely fixed to the anode surface, the exposed anode surface is observed and the display quality is reduced, Since the light emitting area is reduced, the luminance is also reduced. Therefore, the thickness dimension is more preferably 10 (μm) or more. Further, when the total film thickness exceeds 60 (μm), since the anode current is significantly suppressed by the phosphor having low conductivity and the luminance is reduced, the total film thickness is not more than the above value. It is preferable to set the thickness of each layer. That is, the maximum thickness of each layer is preferably 50 (μm) or less.

[0013] Preferably, the second phosphor layer has coarse phosphor particles to such an extent that the first phosphor layer is exposed in order to generate a color mixture of the first wavelength and the second wavelength. It is provided so as to be distributed. With this configuration, since the light emission of the first phosphor layer is observed between the phosphor particles constituting the second phosphor layer, the light emission of the second phosphor layer is preferably performed within the range where the second phosphor layer is provided. An intermediate color is obtained by mixing the color phosphors. Moreover, when compared to the case where the anode surface is divided into a plurality of portions such as grids and painted to express an intermediate color by mixing colors, the number of the segments is substantially larger and the size of each segment is significantly larger. Therefore, it is possible to obtain a good intermediate color display in which it is more difficult to distinguish each color tone.

Preferably, when the phosphor particles of the second phosphor layer are coarsely distributed as described above, the second phosphor layer has a lower luminance than the first phosphor layer. . According to this configuration, in the portion where the second phosphor layer overlaps the first phosphor layer, the light emission of the first phosphor layer is not substantially blocked by the light emission of the second phosphor layer located on the upper side. Are preferably observed. Therefore, at the position where they overlap, light of each emission wavelength of the first phosphor layer and the second phosphor layer is mixed, so that light having a high-luminance wavelength characteristic over a wide wavelength range is observed. Accordingly, a display pattern having a color tone having a wide peak wavelength such as white can be obtained.

Preferably, the second phosphor layer has higher brightness than the first phosphor layer. According to this configuration, even in the portion where the second phosphor layer overlaps the first phosphor layer, the second phosphor layer has the same pattern in the pattern of the second phosphor layer regardless of the thickness dimension of the second phosphor layer. Emission of one phosphor layer is not substantially observed. Therefore, the patterns formed by the first phosphor layer and the second phosphor layer respectively emit light in the desired colors, and the second phosphor layer is placed at a position where a part of the second phosphor layer overlaps the first phosphor layer. A change in emission color due to the provision is suitably suppressed, and high display quality is obtained. That is, whether the brightness of the first phosphor layer and the second phosphor layer is high or low depends on whether the pattern formed by the second phosphor layer emits light in the original color tone or the pattern emits light in the mixed color tone. What is necessary is just to determine suitably.

[0016] Preferably, the predetermined shape is a shape in which a plurality of small area portions are distributed on the first phosphor layer. With this configuration, the size and distribution of each small area portion, the area ratio between the portion where the first phosphor layer is exposed and the small area portion between the small area portions, and the like are appropriately set. Thereby, various display modes can be easily realized. For example, when the individual small area portions are provided with a relatively large area, each of them is observed in the original emission color of the second phosphor layer. Conversely, when individual small area portions are provided with a relatively small area (ie, a plurality of small area portions are distributed on the first phosphor layer in order to generate color mixing of the first wavelength and the second wavelength). In each case, the color mixture of the first phosphor layer according to the area ratio between the exposed portion and the small area portion may be different from each other on the first phosphor layer, depending on the individual size and distribution of the small area portion. Observed with corresponding tone uniformity. That is, by variously determining the area ratio, it is possible to obtain an extremely large number of emission colors while using several kinds (for example, about 3 to 4 kinds) of phosphors. Further, the uniformity of the color tone is enhanced as the area of each small area portion is smaller and the uniformity of the distribution density is higher.

Preferably, the plurality of small area portions are distributed at a uniform area density on the first phosphor layer. In this way, an emission pattern of a neutral color having a uniform color tone by mixing the first and second phosphor layers within the distribution area of the small area where the first and second phosphor layers overlap is obtained.

Preferably, the plurality of small area portions have the same area as each other and are arranged at a constant interval. In this case, since the small area portions are distributed with a uniform area density, a light emission pattern of a neutral color having a uniform color tone by mixing the first phosphor layer and the second phosphor layer is obtained.

Preferably, the fluorescent display tube includes a plurality of anodes having different area densities of the plurality of small area portions on the first phosphor layer. In this case, the patterns in which the area densities of the small area portions are different from each other have different intermediate colors obtained by mixing the first phosphor layer and the second phosphor layer. Therefore, various color tone patterns can be obtained without particularly increasing the types of phosphors used. In addition, since the area ratio between the first phosphor layer and the second phosphor layer can be changed between the plurality of anodes, a more versatile expression can be achieved by controlling light emission for each anode. .

Preferably, in the plurality of small area portions, the area density on the first phosphor layer changes in a predetermined direction. In this way, by changing the area density in a predetermined direction, it is possible to form a pattern in which the color tone of the intermediate color changes due to color mixture in that direction.

Preferably, the area density of the plurality of small area portions increases continuously or stepwise in a predetermined direction. In this case, since the area density is changed so as to increase continuously or stepwise, a gradation display in which the color tone changes continuously or stepwise can be obtained.

Preferably, the area density of the plurality of small area portions on the first phosphor layer is different from each other in at least one of the area of each of the small area portions and the mutual interval. It has been changed by In this case, if the area of the small area portion or the mutual interval is changed, the area ratio between the first phosphor layer and the second phosphor layer is changed. Can be.

Preferably, the plurality of small area portions are a plurality of points or a plurality of lines parallel to each other.
In this way, it is relatively difficult to recognize the shape of each of the linear and dot-shaped patterns, and it is not possible to identify the boundary between adjacent patterns at an appropriate observation distance. By appropriately determining the area density of the small area portions on the layer, it is possible to easily express a desired intermediate color according to their area ratio. In addition, even if the relative positions of the first phosphor layer and the second phosphor layer are shifted, the ratio of their area ratio is not affected at all, and is maintained at the expected value. For this reason, the size of each of the second phosphor layers formed in the form of dots or lines can be made sufficiently small without considering the deterioration of the quality due to the positional shift, so that the display quality due to the color mixture is improved. Can be Preferably, the plurality of points are
They are arranged along two directions crossing each other. When the small area portion is composed of dots, the area can be changed by changing the diameter. When the small area portion is constituted by parallel lines, the area can be changed by changing the width dimension, for example. In the present application, the “line” includes a band-like shape or a plate-like shape having a certain width dimension.

For example, in a display pattern including a plurality of anodes having different area densities of the plurality of small area portions, a plurality of lines having different widths from each other are parallel to each other. A plurality of anodes having different diameters are arranged in parallel, or a plurality of lines having different intervals are arranged in parallel with each other, and a plurality of points having different diameters intersect with each other. The anodes are arranged in two directions, or alternatively, the anodes are arranged in two directions intersecting each other with a plurality of points having mutually different intervals.

Preferably, the fluorescent display tube is provided in contact with an outer peripheral edge of the first phosphor layer and generates visible light of a third wavelength different from the first wavelength and the second wavelength. A third phosphor layer to be formed, wherein the second phosphor layer partially covers a boundary between the first phosphor layer and the third phosphor layer. By doing so, one anode (segment) pattern is made to emit light in the original emission color of each of the three types of phosphors and a mixed color thereof, so that a more versatile display is possible. At this time, if the relative positions of the first phosphor layer and the third phosphor layer change, gaps and overlapping portions may occur between them. However, since the second phosphor layer is provided on those boundaries in an overlapping manner, even if there is a gap there, it is covered with the second phosphor layer.
Therefore, a change in the relative positions of the first phosphor layer and the third phosphor layer does not affect the display quality at all, so that a multicolor display fluorescent display tube can be easily obtained.

Preferably, the fluorescent display tube covers a part of the remaining portion of the first phosphor layer which is not covered with the second phosphor layer, and is provided with the first wavelength and the second wavelength. Include a third phosphor layer that generates visible light of a different third wavelength. By doing so, one anode (segment) pattern is made to emit light in the original emission color of each of the three types of phosphors and a mixed color thereof, so that a more versatile display is possible. At this time, if the relative position of the second phosphor layer and the third phosphor layer changes, the design of the entire pattern may change. However, such a shape in which the change in the relative position does not matter so much, for example, the distance between them may be changed. Such a structure can be adopted for a sufficiently large shape or the like. In this embodiment, the above-mentioned “including a third phosphor layer that is provided in contact with the outer peripheral edge of the first phosphor layer and generates visible light of a third wavelength different from the first wavelength and the second wavelength. The second phosphor layer partially covers the boundary between the first phosphor layer and the third phosphor layer, and the obtained visual effect is the same. Any of these may be used in consideration of the printing process efficiency and the like in relation to the printing order of the plurality of types of phosphors and the color arrangement of other portions.

Preferably, the fluorescent display tube covers a part of the second phosphor layer and generates a third visible light having a third wavelength different from the first wavelength and the second wavelength.
It contains a phosphor layer. By doing so, one anode (segment) pattern is made to emit light in the original emission color of each of the three types of phosphors and a mixed color thereof, so that a more versatile display is possible.

Preferably, the planar shape of the portion of the second phosphor layer on which the third phosphor layer is laminated is larger than the planar shape of the third phosphor layer by a predetermined value or more. It is provided. With this configuration, even if the relative positions of the third phosphor layer and the second phosphor layer change, the planar shape of the second phosphor layer is larger than the third phosphor layer by a predetermined value or more. A change in the shape or the actual emission color due to the change in the relative position is suppressed in accordance with the difference in height. Preferably,
The predetermined value is set to a size corresponding to a range where the relative position between the second phosphor layer and the third phosphor layer can change.

Preferably, the predetermined shape is a shape in which a part thereof protrudes from above the first phosphor layer. With this configuration, since the first phosphor layer is not entirely placed on the first phosphor layer and the predetermined shape is initially determined to protrude from the first phosphor layer, the second phosphor layer and the first phosphor having the predetermined shape are determined. Even if the relative position with respect to the layer changes, the change in the design due to the change in the relative position is negligible in the degree of the printing position shift. That is, by providing the second phosphor layer so as to overlap a part of the first phosphor layer, even if the relative position is shifted, regardless of the presence or absence of the protruding portion,
The shapes of the first phosphor layer and the second phosphor layer are maintained in substantially desired shapes, and no gap is generated between them. Therefore, it is possible to obtain a fluorescent display tube having a display pattern composed of multiple colors without lowering the display quality or increasing the number of steps.

In the case where the predetermined shape is a shape protruding from the first phosphor layer as described above, it is more preferable that the first phosphor layer has the second phosphor layer superimposed thereon. It is provided in a shape to be set if it is not provided. With this configuration, no matter how much the relative position between the first phosphor layer and the second phosphor layer changes, the contour of the light emission shape of each of the first phosphor layer and the second phosphor layer is not changed. It does not change. Therefore, the shape maintaining performance with respect to the change in the relative position is further enhanced, and the deterioration of the display quality is further suppressed.

The predetermined shape is the same as the first phosphor layer. That is, the first phosphor layer and the second phosphor layer
In the phosphor layer, patterns having the same shape are provided with their relative positions shifted. In this way, a three-dimensional phosphor display can be obtained by the two-color phosphors, and even if their relative positions change due to a printing position shift, only a slight change in the degree of overlap is caused. Without this, multicoloring and further diversification of display are further facilitated.

[0032]

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

FIG. 4 is a perspective view showing the entire structure of a fluorescent display tube 30 as one application example of the present invention, with a part thereof being cut away. In the figure, a fluorescent display tube 30 has a substrate 32 made of a flat plate made of an insulating material such as glass, ceramics, and enamel.
And cover glass plate 34 made of transparent glass plate
, A rectangular frame-shaped spacer glass 36, and their substrates 3
2, a plurality of anode terminals 38p, a plurality of grid terminals 38g, and
And a pair of cathode terminals 38k, and the substrate 32 and the cover glass plate 34 are joined together by glass sealing via a spacer glass 36 to form a long flat box-shaped airtight container. A vacuum space surrounded by these members is formed inside.

One side 4 of the substrate 32 covered by the vacuum space
Numeral 0 functions as a display surface of the fluorescent display tube 30. The display surface 40 may include, for example, characters as shown in FIG. 5, a plurality of strips, or 8 segments of 7 segments.
1 each composed of various pattern shapes such as
A plurality of display patterns 44 including one or a plurality of phosphor layers 42 (see FIG. 6 and the like) are provided. The phosphor layer 42 constituting each display pattern 44 has, for example, (Zn _x Cd _{(1- x)} ) S of red (R) emission having a peak wavelength of about 650 (nm).
Ag, Cl phosphor, ZnS: Cu, Al phosphor with green (G) emission with a peak wavelength of about 525 (nm), blue with a peak wavelength of about 445 (nm)
(B) A variety of luminescent colors such as a ZnS: Cl phosphor of luminescence and a yellow (Y) luminescence of (Zn _x Cd _(1-x) ) S: Ag, Cl phosphor of a peak wavelength of about 565 (nm). A phosphor corresponding to a desired emission color is appropriately selected and used from various phosphors. Note that the red light-emitting phosphor and the yellow light-emitting phosphor have the same composition but different Zn and Cd ratios x and (1-x), and those having appropriate values to obtain a desired color tone are used. Can be On the display surface 40, a plurality of mesh-shaped grid electrodes 4 divided mainly in the longitudinal direction and, if necessary, also in the width direction.
6 are arranged to cover one or more display patterns 44, that is, one or more phosphor layers 42, respectively. In FIG. 4, the display pattern 44 is shown by breaking off the middle part of the grid electrode 46 located closest to the front.

FIG. 6 shows the fluorescent display tube 3 at an appropriate position.
FIG. 2 is a diagram illustrating a configuration of a main part using a cross section of 0. On the display surface 40 of the substrate 32, a plurality of anode wirings 48 and grid wirings 50 are provided below the insulator layer 52 that covers substantially the entire display surface 40. At a plurality of locations on the insulator layer 52, anodes 54 are provided.
Is conducted to the above-described anode wiring 48 through through holes 56 provided at a plurality of locations through the insulator layer 52. The anodes 54 are, for example, a common anode wiring 4 for each of a plurality of rows arranged substantially along the longitudinal direction of the fluorescent display tube 30.
8 is connected. Further, the grid electrode 46
At the position where the grid wiring 50 is exposed by the through hole 56, the leg is fixed to the display surface 40 in a state where it is electrically connected to the grid wiring 50 by fixing the legs with a conductive adhesive or the like. ing.

The above anode wiring 48 and grid wiring 5
0 is formed, for example, by screen-printing a thick-film conductor paste to a thickness of about 15 (μm) or by etching a thin film of aluminum or the like formed by evaporation. In addition, the above-mentioned insulator layer 52
For example, a thick film insulating paste composed of a low-melting glass and a coloring pigment such as black is screen-printed or the like to 30 to 40 (μ).
m) It is formed by applying to a thickness of about m) and firing. The anode 54 is provided by screen-printing and firing a thick-film conductor paste containing, for example, graphite as a main component to a thickness of about 40 (μm). The phosphor layer 42 provided on the display surface 40 is fixed on the anode 54, and as is apparent from the figure, the anode 54 is slightly smaller than the phosphor layer 42 provided on each of them. It has a large pattern shape.

Referring back to FIG. 1, a plurality of terminal pads 58 are provided on the display surface 40 of the substrate 32 along the long sides thereof. The anode wiring 48 and the grid wiring 50 on the display surface 40 are formed on the substrate 32 or the insulator layer 52.
It is connected to any of these terminal pads 58 via the upper side. The anode terminal 38p and the grid terminal 38g are connected to the terminal pad 58 in an airtight container.
The anodes 54 and the grid electrodes 46 are connected to the terminals 38p and 38g via the terminal pad 58, the anode wiring 48, the grid wiring 50, and the like.
, A driving voltage is applied.

At both ends of the substrate 32, a pair of filament supporting frames 60 provided with the cathode terminals 38k (only one located at the right side in the figure is shown).
Are fixedly provided on the display surface 40, respectively. Between the filament support frames 60, a plurality of thin filament cathodes 6 functioning as a direct heating cathode
2 is extended at a predetermined height position parallel to the longitudinal direction of the substrate 32 and separated from the phosphor layer 42 (that is, bridged over the phosphor layer 42). The filament cathode 62 is made of a tungsten (W) wire having a surface coated with an oxide solid solution of an alkaline earth metal having a low work function such as (Ba, Sr, Ca) O as an electron emitting layer. Note that the fluorescent display tube 30 is provided with a getter for increasing the degree of vacuum in the hermetic container, and an exhaust pipe or an exhaust hole for evacuating the inside of the hermetic container to form a vacuum after the hermetic container is formed. 4 and 6 are omitted.

When driving the fluorescent display tube 30 configured as described above, the grid electrode 42 is driven by, for example, time-division driving while thermionic electrons are emitted by the current flowing through the filament cathode 62. In synchronization with the sequential application of the positive voltage, the plurality of phosphor layers 42
A positive voltage is applied to the desired one through the anode 54. The thermoelectrons emitted from the filament cathode 62 are accelerated by the grid electrode 46 to which a positive voltage (acceleration voltage) of, for example, about 20 (V) is applied to the zero (V) filament cathode 62. Therefore, if a positive voltage is also applied to the phosphor layer 42 covered by the grid electrode 46, thermions collide with the phosphor layer 42 to cause the phosphor layer 42 to emit light. Even if a positive voltage is applied to 42, if a negative bias voltage of about several volts (cutoff bias = negative erase voltage) is applied to the filament cathode 62 to the grid electrode 46 surrounding it, The thermoelectrons do not reach the phosphor layer 42, and the phosphor layer 42 does not emit light. Therefore, light-emitting display is performed in a desired pattern by so-called dynamic driving.

For example, in FIG. 5, a plurality of "MASTER" character patterns 44a located at the upper right are colored in red or yellow, green to yellow, or blue to green in the horizontal or vertical direction. The two "LOCK" character patterns 44b located in the vicinity of the changing colors are blue characters on a yellow background, or red characters on a blue background, and extend over the entire length in the middle to lower stages in the longitudinal direction. , A plurality of band-shaped patterns 44c are arranged such that colors change from red to blue through green, blue through green through yellow, or yellow through blue through intermediate colors, or N, R in various colors. , Ν, etc., a pattern and pattern of a plurality of eight-characters 44 located at the center from the left end to the right and the left end in the upper stage,
d and 44e are colors in which the seven segments change color from yellow to blue, white to blue, etc., or shades of blue with yellow or red, or small yellow or red in seven segments such as red. Light-emitting display is performed in a color and a shape in which a rectangle such as green, a triangle, a circle, or the like intersects. The fluorescent materials used in the fluorescent display tube 30 are, for example, four colors of red, green, blue, and yellow as described above, but as described above, intermediate colors of various colors are displayed without unevenness. Further, even in a pattern in which characters and figures of various colors overlap, there is no gap between the phosphors constituting the pattern.
In the fluorescent display tube 30, the light emission observation direction is on the surface side of the phosphor layer 44, that is, on the cover glass plate 34 side.

The details of the structure of the phosphor layer 42 for realizing the various display patterns as described above will be described in detail below with reference to schematic diagrams showing basic constituent elements and corresponding parts in FIG. The pattern 44 will be described with reference to FIGS. In each of the drawings showing the basic components, (a) is a plan view, (b) is b-
It is sectional drawing seen from b.

In the structure shown in FIG. 7, a phosphor layer A having a similar shape but slightly smaller is fixed to substantially the entire surface of one anode 54 having a rectangular planar shape.
A plurality of circular phosphor layers B are fixed on the surface. That is, the disposition position of the phosphor layer B is determined so as to cover a part of the phosphor layer A. These phosphor layers A and B
For each of the four color phosphor layers, different ones are used. In the present embodiment, the phosphor layer A corresponds to the first phosphor layer, and the phosphor layer B corresponds to the second phosphor layer, respectively. It is distributed on the phosphor layer A, and the plurality of small area portions, that is, the area of the phosphor layer B are the same as each other. Therefore, the emission wavelength (first wavelength) of the lower phosphor layer A, that is, the first phosphor layer, and the emission wavelength (second wavelength) of the upper phosphor layer B, that is, the second phosphor layer, are determined. Are mutually different values, each of which is a wavelength in the visible light range.

The phosphor layer B has an individual diameter.
A circular pattern having a small and uniform diameter of about 50 to 500 (μm), for example, about 250 (μm) (i.e., having a uniform area), and having a diameter of about 2 (mm) ) The distribution is substantially uniform at a center interval (pitch) of about or more. This diameter is appropriately determined in accordance with the viewing distance in use, required display quality, and the like, in a range sufficiently smaller than the size of the phosphor layer A provided, for example, about 2 × 6 (mm). Phosphor layer B
Are arranged along two directions indicated by broken lines in the figure, and the mutual interval is constant in any direction. The thickness of the phosphor layer A is, for example, about 10 to 50 (μm),
For example, the thickness is about 20 (μm), and the thickness of the phosphor layer B is, for example, about 20 to 150 (%) of the phosphor layer A, for example, 20 (μm).
It is about.

Therefore, in the display pattern formed by laminating the phosphor layers A and B, since the two kinds of phosphors emit light at the same time, the emission color actually transferred to the eyes of the observer is obtained. Is an intermediate color due to their mixture. The color tone of the intermediate color is determined by the emission color and luminance of each of the phosphors and the area ratio of each other. Although the phosphor layer A is provided on substantially the entire surface of the anode 54, the portion where the phosphor layer B is overlapped does not emit light.
The substantial area is obtained by subtracting the area covered by the phosphor layer B from the fixed area. Therefore, a desired intermediate color can be obtained by appropriately determining the diameter and the number of the phosphor layers B and changing the area ratio of the phosphor layers A and B. In addition, since the distribution of the phosphor layer B is uniform as described above, if an area is selected in a range sufficiently larger than the individual area, how the area ratio with the phosphor layer A is selected The constant value is obtained even in the region
4, an intermediate color having a uniform color tone is observed on the entire surface. As described above, since the phosphor layer A is also fixed to the portion covered with the phosphor layer B, even when their relative positions deviate from the expected positions, the anode 54 is exposed therebetween. Such a gap does not occur. Therefore, according to the present embodiment, both phosphor layers are provided only on the portions on the anode 54 where light is actually emitted (that is, when the phosphor layer A is provided in a perforated pattern). The size of each of the two phosphor layers can be set to any size necessary to obtain a desired color mixture, without taking into account the generation of the resulting gap.

In the above example, the luminance of the phosphor layer A is relatively higher than the luminance of the phosphor layer B. Therefore, in the portion where the phosphor layer A is exposed, the light emission is reduced. B is observed with almost no hindrance by the light emission of B, and the mixed colors thereof are suitably observed according to the area ratio. Therefore, if the luminance of the phosphor layer A is relatively reduced,
If the thickness of the phosphor layer B is appropriately small, the light emission will leak out even in the portion covered by the phosphor layer B. In addition, an intermediate color due to color mixture with the emission of the phosphor layer A emitted without being blocked by the phosphor layer B is observed.

FIG. 8 shows the phosphor layer 4 of the pattern 44c shown in FIG.
FIG. 7 shows an arrangement state of the phosphor 2 and is an application example of the phosphor arrangement shown in FIG. In the figure, the plurality of rectangular patterns are all provided on one anode 54,
They may be provided on separate anodes 54, respectively. In each of the rectangular patterns, a portion without hatching corresponds to the phosphor layer A (first phosphor layer) in FIG. 7, and a hatched portion corresponds to the phosphor layer B (second phosphor layer) in FIG. ). Only the phosphor layer A is fixed to h located at the middle stage, while a small-diameter circular phosphor layer B is fixed to b to g and in to n. Further, a phosphor layer B is fixed to the entire surface of a and o.
In any of the patterns a to o, the phosphor layer B is fixed on the rectangular phosphor layer A with a uniform distribution, and each pattern has an intermediate color corresponding to the area ratio of the phosphor layers A and B. To emit light. For example, if the emission color of the phosphor layer A is blue, the emission color of the phosphor layer B is red for a to g, and green for i to o, a emits red, h emits blue, and o emits green. , B to g are emitted in purple, which is an intermediate color between red and blue, and i to n are emitted in blue-green, which is an intermediate color between green and blue. However, each emission color is determined by the phosphor layers A and B
Are different colors depending on the area ratio of. That is, a desired intermediate color can be obtained by adjusting the arrangement density of the phosphor layers B as shown in FIG.

In FIG. 8, the vertical dimension and the mutual interval in each rectangular pattern in the figure are, for example, about 100 (μm), respectively, but this value is substantially equal to the maximum displacement of the printing position. . Therefore, in the case of forming each of the rectangular patterns a to o using different phosphors in order to emit light in different colors and sequentially using different screen plates, the relative positions of the plurality of rectangular patterns are Since there is no limitation, it is difficult to realize a shape in which rectangular patterns of different emission colors are arranged at equal intervals as shown in the figure. According to the present embodiment, since multiple colors can be obtained by simultaneously printing phosphors of about two or three colors on any rectangular pattern, a remarkable decrease in display quality due to a printing position shift cannot occur. There are advantages.

FIG. 9 shows a pattern for expressing an intermediate color of a uniform color over the entire surface of the anode 54 in the same manner as FIG. 7, and the phosphor layer A is provided on the anode 54 in the same manner. The body layer B is provided with a plurality of thin layers having a width dimension substantially the entire length in the width direction of the phosphor layer A and a width dimension sufficiently smaller than the vertical dimension.
Each line width is a constant dimension of, for example, about 100 (μm), and the width dimension is appropriately set within a range of about 50 to 500 (μm) according to a used viewing distance and a required display quality. Selected. Further, the phosphor layers B are provided in parallel with each other, and the center interval thereof is a constant value of, for example, about 200 (μm). These values correspond to the phosphor layer B overlying the phosphor layer A.
Is appropriately determined in accordance with the total area of. That is, even in the arrangement pattern shown in FIG. 9, the phosphor layers B are uniformly distributed over the phosphor layers A so as to partially cover the phosphor layers A. Therefore, also in this case, an intermediate color corresponding to the area ratio of the phosphor layers A and B can be displayed, and even if their relative positions are shifted, there is no gap between them. As described above, if the phosphor layer B superposed on the phosphor layer A is formed in a dot shape or a line shape, such a pattern is inherently difficult to discriminate each other, so that a suitable color mixture can be obtained.

FIG. 10 shows the phosphor layer 4 of the pattern 44c shown in FIG.
FIG. 9 illustrates an arrangement state of No. 2 and is an application example of the phosphor arrangement illustrated in FIG. 9. In this pattern, as in the pattern of FIG. 8, the whole of the plurality of rectangular patterns is provided on one anode 54 or on separate anodes 54. In each of the rectangular patterns, a portion not shaded corresponds to the phosphor layer A, and a shaded phosphor layer B, and only the phosphor layer A is fixed to h located at the middle stage. However, a thin phosphor layer or a band-like phosphor layer B having a predetermined width is fixed on b to g and in to n. In any of the patterns a to o, the phosphor layer B is fixed on the rectangular phosphor layer A with a uniform distribution, and each pattern has an intermediate color corresponding to the area ratio of the phosphor layers A and B. To emit light.

The above-mentioned intermediate color can also be obtained by, for example, providing the upper phosphor layer B over the entire surface of the phosphor layer A such that the phosphor particles are sparsely distributed on the phosphor layer A. It is feasible. That is, in the phosphor layer B in which the phosphor particles are sparse, the portions (holes) where the phosphor layer A is exposed are uniformly distributed, and therefore, the phosphor layer B has substantially the same configuration as that shown in FIGS. To cover a part of the phosphor layer A. Such a phosphor layer B is prepared, for example, by preparing a phosphor paste in which the solvent component and the resin component are relatively increased and the filling rate of the phosphor particles is reduced (diluted), and a normal screen printing method is used. It can be formed by following the phosphor layer forming method. The film formed from the diluted paste has a thickness of about 5 to 40 (μm) depending on the degree of dilution after baking for removing the resin component, so the degree of dilution is appropriately adjusted. By changing the film thickness, the degree of transmission of light emitted from the phosphor layer A can be adjusted. In the case of displaying an intermediate color in this manner, different colors are alternately arranged according to the size of the phosphor particles, so that the circular or linear phosphor layer B is formed as described above. Since the number of sections of the phosphor layers A and B is dramatically increased and the size of each section is significantly reduced to such a degree that it cannot be distinguished even at a close distance, An intermediate color having a more uniform color tone is obtained. Moreover, if the upper phosphor layer B is made of a phosphor having a relatively low luminance, white light emission with a wide peak wavelength width can be achieved.

Contrary to the above, when it is desired to prevent the light emission of the phosphor layer A from being transmitted through the phosphor layer B and to be observed, and to display the original emission color of the phosphor layer B. It is apparent from the above that it is preferable to increase the thickness of the phosphor layer B. In general, when the upper phosphor layer B has a thickness of 40 (μm) or more, preferably 50 (μm) or more, and more preferably about 60 (μm) or more, light emission of the phosphor layer A can be blocked. The thickness of the phosphor obtained by normal screen printing is about 20 (μm), but if the phosphor paste is applied in the same pattern after printing and drying, a phosphor layer having a desired thickness dimension can be obtained. .

In the configuration example shown in FIG. 11, a plurality of thin line-shaped or band-shaped phosphor layers B are laminated on the phosphor layer A, but their width dimensions are not uniform. The width dimension is increased downward. Therefore, unlike the case shown in FIG. 9 described above, the ratio of the light emitting area of the phosphor layer A to the light emitting area of the phosphor layer B is such that the area ratio of the phosphor layer B increases in the vertical direction. It changes step by step. As a result, in the upper part of the figure, the light emission amount of the phosphor layer A is relatively increased, while in the lower part, the light emission amount of the phosphor layer B is conversely increased. , The gradation display changes stepwise so as to be closer to the color tone of the phosphor layer B as going downward. In the example shown in the figure, the area ratio is changed only by changing the width of the phosphor layer B. However, the center interval may be changed, or both the width and the center may be changed. Similar gradation display can be realized.
Also, when the phosphor layer B is provided in a small circular pattern as shown in FIG. 7 instead of a fine line pattern,
Similarly, the area ratio can be changed by changing at least one of the individual area and the center interval, so that gradation display can be performed. The change in the area ratio may be continuous. For example, in a pattern in which small circles are distributed, the change in the area ratio is a substantially continuous change in the area ratio such that a discontinuous change in color tone cannot be observed. It is easy.
In the case where such a gradation display pattern is formed, it is better to avoid the emission of the phosphor layer A located on the lower side from being transmitted through the phosphor layer B and to observe the dynamic range. Since the printing order can be widened, it is preferable to set the printing order so that a relatively light color (or a low-brightness color) is on the lower side.

FIG. 12 shows the pattern 4 in FIG.
FIG. 12 is a diagram for explaining an arrangement state of 4a, and is an application example of the phosphor arrangement shown in FIG. The letters “MASTER” shown in the figure indicate that after the phosphor layer A is fixed on the whole, the phosphor layer B has a band-like pattern thereon as shown in FIG. It is provided to be large. Therefore, in this character pattern, the observed luminescent color gradually changes in the vertical direction from the luminescent color of the phosphor layer B to the luminescent color of the phosphor layer A via the intermediate colors thereof. For example, when the phosphor layer A has a yellow emission color and the phosphor layer B has a green emission color, the color changes from yellow to yellow green to green. Is closer to yellow at the lower end and closer to green at the upper end.

In the configuration example shown in FIG. 13, a plurality of (for example, four) anodes 54 are provided with phosphor layers A and B so as to have an arrangement pattern as shown in FIG. 11 as a whole. Have been. Also in this case, these anodes 5
Similarly, gradation display can be realized with the entire pattern composed of four. In addition, in this example, since the anode 54 is divided into a plurality of anodes, it is possible to control the lighting and extinguishing of the anodes separately. Display becomes possible. Note that the area ratio of the phosphor layers A and B is uniform on each anode 54, and the anode 5
Light is emitted in a uniform color tone every four.

The pattern 44 shown in FIG.
8C, the phosphor layer 42 is formed as shown in FIG. 11 or FIG. 13 as apparent from FIG. 8 and FIG. That is, the area ratio between the phosphor layer A and the phosphor layer B changes from the center upward and downward. Therefore, a gradation display in which the color tone changes in the vertical direction in FIG. 5 can be obtained.

FIG. 14 is a diagram for explaining the configuration of the figure-eight pattern 44f composed of seven segments located at the upper right in FIG. 5, and adopts the configuration shown in FIG. 13 described above. It is. In this pattern, the phosphor layer B indicated by oblique lines is placed on the phosphor layer A indicated by white so that the area density gradually decreases from top to bottom. Therefore, each segment is caused to emit light with a color tone different from each other and gradually changing from top to bottom. As a result, in this pattern,
Select the segment to be lit, and display
Display with different (color tone) can be obtained.

In the structure shown in FIG. 15, a phosphor layer A is fixed to an upper half on a rectangular anode 54 extending vertically, while phosphor layers A and B are fixed to a lower half. The phosphor layers C having different emission wavelengths are fixed to all of them. On each of the phosphor layers, a thin line-shaped or band-shaped phosphor layer B whose width decreases in a vertical direction from the center is provided at a predetermined center interval. With such a phosphor arrangement, a gray scale display by color mixture similar to the case of the phosphor arrangement shown in FIG. 11 can be obtained in the upper and lower half ranges. At this time, since the emission colors of the lower phosphor layers A and C are different from each other, the emission color of the phosphor layer A changes from the emission color of the phosphor layer B toward the center in the upper half range. In the lower half range, the emission color of the phosphor layer C changes from the emission color of the phosphor layer B toward the center.

In this arrangement, the phosphor layer C is provided adjacent to the phosphor layer A. However, the boundary is not exposed because it is covered with the portion of the phosphor layer B having the largest width located at the center in the vertical direction. Therefore, even if a gap is formed between the phosphor layers A and C at the boundary, the exposed anode 54 is covered with the phosphor layer B, so that the printing accuracy of the phosphor layers A and C is improved in display quality. Does not affect Note that the position and size of the central portion of the phosphor layer B need to be determined so that the boundary portion cannot be exposed even if the printing position is shifted. In other words, since the position of the boundary between the phosphor layers A and C only needs to be within a range that is hidden by the phosphor layer B, the position of the boundary with respect to the phosphor layer B is considered in consideration of the printing position shift. It is necessary to determine such a relationship.

In the configuration example shown in FIG. 16, the phosphor layer A is fixed on the entire surface of the anode 54, while the phosphor layer B is formed on the upper half of the rectangular phosphor layer A in a fine line or band pattern. Are fixed, and the phosphor layer C is fixed to the lower half in a fine line or band pattern. Therefore, even in this phosphor arrangement, the upper half is caused by the mixed color of the phosphor layers A and B, and the lower half is caused by the mixed color of the phosphor layers A and C in FIG.
Is obtained. In this pattern, the case where the relative positions of the phosphor layers B and C are deviated may be a problem. However, if the mutual interval of the areas where the phosphor layers B and C are arranged is made large, the mutual interval may occur in printing accuracy. Even if it deviates slightly, there is no problem visually.

These two types of phosphor structures have the same effect. Therefore, according to the relationship between the printing order for each type of phosphor and the color arrangement of other parts, etc., it is convenient in relation to the restriction on the printing order between the upper phosphor layer and the lower phosphor layer. The better one is selected.

The pattern 44g shown in FIG.
15 and 16 are applied. For example, if the phosphor layers A, B, and C in FIG. 15 are red, yellow, and green, respectively, red → orange → yellow → A gradation display in which the color tone changes from yellow-green to green is observed.

In the above description, the anode 54 is formed in a rectangular shape. However, if the above-described phosphor structure is applied to, for example, characters, symbols, and figures having a certain shape, a logo whose color changes with gradation is obtained. And symbols.

FIG. 17 illustrates a configuration example in which the phosphor layers A, B, and C are stacked in three layers. By laminating in this manner, an intermediate color of three colors can be displayed. In this case, since the phosphor layer A is provided on the entire surface of the anode 54, the displacement of the phosphor layer B provided thereon is not a problem, but the phosphor layer C
Is provided on the phosphor layer B, the relative positional accuracy becomes a problem. In this case, the relationship between the width dimension b of the phosphor layer B and the width dimension c of the phosphor layer C is such that the entire phosphor layer C is positioned above the phosphor layer B even if both phosphor layers are displaced. It suffices that the difference between the widths b and c is set to be smaller than the maximum displacement of the relative position due to displacement (usually about 100 (μm)) as if riding. Note that such a pattern is shown in FIG.
Is applied to the pattern below the numeral 14 or the like, for example, so that the longitudinal direction of the thin line-shaped phosphor layers B and C is the vertical direction in the figure.

In the configuration example shown in FIG. 18, a strip-shaped phosphor layer A is provided on a part of the surface of the anode 54, and a circular phosphor layer B having a diameter larger than its width is provided from above. Have been. That is, the phosphor layer B partially protrudes from above the phosphor layer A. The size of the anode 54 is such that even if the two phosphor layers A and B are displaced, the entirety of the anode layer 54 can be securely mounted. In this arrangement example, a part of the phosphor layer B rides on the phosphor layer A, and the other part is formed directly on the anode 54. The figure in which the rectangular pattern is in contact with the left and right sides can be observed. Therefore, even if the relative positions of the phosphor layers A and B are displaced, no gap is formed between them, and the impression of the entire figure hardly changes when the printing position is displaced. Note that this arrangement is not intended for an intermediate color by color mixture, but is intended to enhance a visual effect by painting one figure or the like in multiple colors.

FIGS. 19 and 20 correspond to the numerals 8 and 8 in FIG.
18A and 18B are for explaining in detail the patterns shown below 3, 4, and the character R, and the pattern 44e, and are an application example of the configuration of FIG. 18 described above. In the example shown in FIG. 19A, a check mark-shaped phosphor layer B is provided on two strip-shaped phosphor layers A. In the examples shown in (b) and (c), a thick wavy phosphor layer B or a thin wavy phosphor layer B is placed on a strip-shaped phosphor layer A. (D)
In the example shown in FIG. 5, a narrow annular phosphor layer B is mounted on a strip-shaped phosphor layer A. In the example shown in FIG. 20, a phosphor layer B having a triangular shape, a circular shape, a rectangular shape, or the like is overlaid on each of the fluorescent material layers A constituting the figure-eight segment. In any of these patterns, the phosphor layer B does not entirely cover the phosphor layer A and does not cover the entire phosphor layer A. Without creating a gap between each other, and
Multicolor symbols can be displayed without changing the impression caused by the relative position change.

In the pattern shown in FIG. 21, two color phosphor layers A and B each representing a character string "AB" having the same shape and the same size are arranged so that their positions are slightly different from each other. It is provided. The phosphor layers A and B overlap each other for the most part, but a part of the phosphor layer A is exposed,
Part of the phosphor layer B is directly fixed on the anode 54.
In this pattern, the phosphor layer A, which is located on the lower side and most of the portion is covered by the phosphor layer B, is also provided in such a portion that does not substantially emit light.
Even if the printing position is relatively shifted, the area covered by the printing position changes only slightly. As a result, there is no gap between them due to insufficient printing accuracy, and even if their relative positions change, the appearance hardly changes. Grade is maintained at the expected level. In such a configuration example, by appropriately selecting the colors of the phosphor layers A and B, the lower phosphor layer A is displayed as shade of the upper phosphor layer B. Can be given a three-dimensional effect.

FIG. 22 shows a pattern 4 shown in FIG.
4h, which is an application example of the configuration of FIG. 21 described above. Each of the plurality of segments provided in a figure eight shape has a phosphor layer B of the same shape and the same size on the phosphor layer A.
Are shifted from each other so as to slightly overlap each other. Therefore, since all the segments are given a three-dimensional effect in the same color tone, it is possible to display a three-dimensional number by lighting only a necessary segment in a normal operation.

In the example shown in FIG. 23, a rectangular frame-like pattern along the outline of the rectangular phosphor layer A fixed to substantially the entire surface of the anode 54 and the character "AB" Is provided. Also in this phosphor configuration, the phosphor layer A that emits light in a pattern in contact with the pattern constituted by the phosphor layer B is provided on the entire surface of the anode 54 including the portion covered by the phosphor layer B. Therefore, even if the formation position of the phosphor layer B is shifted with respect to the phosphor layer A, the anode 54 is exposed at the boundary between them and the emission area of the phosphor layer A changes. Absent. Therefore, it is possible to form a multicolor pattern in which the phosphor layer A is provided on the background of the character pattern composed of the phosphor layer B without requiring a very high printing accuracy.

The phosphor layer A is not necessarily limited to a pattern that covers the entire surface of the anode 54. Depending on the content to be expressed, the shape may be such that a part of the phosphor layer B directly rides on the anode 54. For example, the phosphor layer A may be provided only on the lower half in the figure, and only the lower half of the character “AB” may be provided so as to ride on the phosphor layer A. It should be noted that the gray scale display obtained by the configuration of FIGS.
The overlapping patterns such as those described above have the phosphor layer for realizing the gradation display as a background, and the phosphor layers of other emission colors in character patterns such as N, R, etc. on them as described above. Are formed by stacking.

FIG. 24 shows the pattern 4 in FIG.
FIG. 24 is a diagram for explaining the configuration of FIG. 4b, and is an application example of the layer structure shown in FIG. In the drawing, a phosphor layer A is provided on the inner peripheral side of a substantially rectangular frame-shaped phosphor layer B, and a character pattern of “LOCK” is provided on the phosphor layer A on the phosphor layer A. Since the pattern 44b has a layer structure as shown in FIG. 23, the phosphor layers A and B
As described above, it is possible to form a pattern in which a background of a different color is provided around a character pattern without requiring a high-precision printing technique so as not to form a gap between them.

That is, in any of the phosphor arrangement examples shown in FIGS. 18 to 24, when forming a pattern composed of phosphors of two colors, the phosphor layers A and B are arranged such that their boundaries overlap each other. By setting the arrangement pattern described above, the portion where the other phosphor is provided does not use a perforated pattern that is exactly the same shape, so that the exposure of the anode 54 due to displacement and the change in appearance are taken into account. Thus, the phosphor layer can be easily formed without performing.

Although the present invention has been described in detail with reference to the drawings, the present invention can be implemented in other embodiments.

For example, in the embodiment, R, G, B,
Although the phosphors of four colors of Y are used, the number of phosphors to be used is related to the range of the color tone to be expressed and the manufacturing cost which increases due to the increase in man-hours according to the number of phosphors. Is changed as appropriate.

In the embodiment, the mesh grid electrode 46 is provided as a control electrode for accelerating the thermoelectrons generated from the filament cathode 62.
For a thin line pattern such as a U-shaped pattern, for example, a pattern having a width dimension of about 0.4 (mm) or less, the control electrode is formed of a conductor provided on the top of a rib-like wall surrounding the phosphor layer 42. It may be used as a rib grid electrode.

Further, in the embodiment, the case where the present invention is applied to the fluorescent display tube 30 in which the light emission of the phosphor layer 42 is observed from the surface side has been described.
The present invention is similarly applicable to a fluorescent display tube called a reverse view of a type in which is provided in a hatching pattern of an aluminum thin film and in which light emission is observed from the back side of the phosphor layer 42. When applied to such a type of display tube, the concept of the upper and lower relationship of the phosphor layers 42 of a plurality of colors is opposite to that of the above-described embodiment. That is, in each of the embodiments described above, in the configuration examples of FIGS. 7 to 14 and FIGS. 18 to 24 in which the phosphor layers A and B of two colors are used, the vertical relationship between the phosphor layers A and B is opposite. Thus, the phosphor layer B is provided between the phosphor layer A and the anode 54. FIG. 15 in which phosphor layers A, B, and C of three colors are used.
17, the vertical relationship between the phosphor layers A and C and the phosphor layer B is opposite in the case of FIG.
In FIG. 17, the vertical relationship between the phosphor layer A and the phosphor layers B and C is opposite, and in FIG. 17, the vertical relationship between the phosphor layers A, B and C is opposite (A is the highest and C is the lowest). ). In other words, the third layer, the second layer, and the first layer are referred to in the claims from the side closer to the observation direction.

Although not specifically exemplified, the present invention
Various changes can be made without departing from the spirit of the invention.

[Brief description of the drawings]

FIGS. 1A to 1C are diagrams for explaining inconvenience of a conventional multicolor pattern.

FIG. 2 is a configuration example when displaying gradation (gradation).

FIG. 3 is a diagram illustrating inconvenience when displaying an intermediate color by mixing colors.

FIG. 4 is a diagram illustrating the overall structure of a fluorescent display tube to which the phosphor structure of the present invention is applied.

FIG. 5 is a diagram illustrating a display pattern provided in the fluorescent display tube of FIG.

6 is a diagram illustrating a cross-sectional structure of the fluorescent display tube of FIG.

FIG. 7 is a diagram illustrating basic components of the display pattern of FIG. 5;

8 is a diagram illustrating a pattern to which the configuration of FIG. 7 is applied among the display patterns of FIG. 5;

FIG. 9 is a diagram illustrating other basic components of the display pattern of FIG. 5;

10 is a diagram illustrating a pattern to which the configuration of FIG. 9 is applied among the display patterns of FIG. 5;

FIG. 11 is a diagram for explaining other basic components of the display pattern of FIG. 5;

12 is a diagram illustrating a pattern to which the configuration of FIG. 11 is applied among the display patterns of FIG. 5;

FIG. 13 is a diagram illustrating another basic component of the display pattern of FIG. 5;

14 is a diagram illustrating a pattern to which the configuration of FIG. 13 is applied among the display patterns of FIG. 5;

FIG. 15 is a diagram for explaining other basic components of the display pattern of FIG. 5;

16 is a diagram illustrating another basic component of the display pattern of FIG. 5 and a pattern configuration used alternatively to the pattern of FIG. 15;

FIG. 17 is a diagram for explaining other basic components of the display pattern of FIG. 5;

FIG. 18 is a diagram illustrating another basic component of the display pattern of FIG. 5;

19 (a) to (d) are diagrams illustrating patterns to which the configuration of FIG. 18 is applied among the display patterns of FIG. 5;

20 is a diagram illustrating a pattern to which the configuration in FIG. 18 is applied among the display patterns in FIG. 5;

FIG. 21 is a diagram for explaining other basic components of the display pattern of FIG. 5;

22 is a diagram illustrating a pattern to which the configuration in FIG. 21 is applied among the display patterns in FIG. 5;

FIG. 23 is a diagram illustrating another basic component of the display pattern of FIG. 5;

24 is a diagram illustrating a pattern to which the configuration of FIG. 23 is applied among the display patterns of FIG. 5;

[Explanation of symbols]

 30: Fluorescent display tube 42: Phosphor layer 54: Anode 62: Filament cathode A: First phosphor layer B: Second phosphor layer

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yasuyuki Kani 2160, Yatsu-cho, Aza-gun, Asakura-gun, Fukuoka No. 2160, Yatsunami Noritake Electronic Industry Co., Ltd. Noritake Electronics Industry Co., Ltd.Yasu Factory, No. 2160, Noritake Electronics Kogyo Co., Ltd. (72) Inventor Kota Hirakawa, Noritake Electronics Industry Co., Ltd.Yasu Factory, Noritake Electronics Industry Co., Ltd. Reference) 5C036 EE04 EF02 EF05 EG36 EH04

Claims (19)

[Claims] 1. An anode provided in a predetermined pattern on a display surface of a substrate, and a phosphor layer fixed to the surface of the anode, wherein electrons generated from a cathode in a vacuum space are incident on the anode. A fluorescent display tube of a type in which a phosphor layer is excited to emit light, wherein the phosphor layer comprises: a first phosphor layer fixed to a surface of the anode for generating visible light of a first wavelength; A second phosphor layer fixed in a predetermined shape so as to cover a part of the first phosphor layer when viewed from the observation direction and generating visible light of a second wavelength different from the first wavelength; And a fluorescent display tube. 2. The fluorescent display tube according to claim 1, wherein the first phosphor layer and the second phosphor layer have a thickness in a range of 5 to 50 (μm). 3. The second phosphor layer is formed such that phosphor particles are coarsely distributed to such an extent that the first phosphor layer is exposed in order to generate a color mixture of the first wavelength and the second wavelength. The fluorescent display tube according to claim 1, which is provided. 4. The fluorescent display tube according to claim 3, wherein said second phosphor layer has lower luminance than said first phosphor layer. 5. The fluorescent display tube according to claim 1, wherein the second phosphor layer has a higher luminance than the first phosphor layer. 6. The fluorescent display tube according to claim 1, wherein the predetermined shape is a shape in which a plurality of small area portions are distributed on the first phosphor layer. 7. The plurality of small area portions are distributed at a uniform area density on the first phosphor layer.
Fluorescent display tube. 8. The fluorescent display tube according to claim 7, wherein the plurality of small area portions have the same area as each other and are arranged at a constant interval. 9. The fluorescent display tube according to claim 8, comprising a plurality of anodes having different area densities of said plurality of small area portions on said first phosphor layer. 10. The fluorescent display tube according to claim 6, wherein the plurality of small area portions change in area density on the first phosphor layer in a predetermined direction. 11. The area density of the plurality of small area parts is:
The fluorescent display tube according to claim 9 or 10, wherein the size of the fluorescent display tube increases continuously or stepwise in a predetermined direction. 12. The area density of the plurality of small area portions on the first phosphor layer is changed by making at least one of the area of each small area portion and the mutual interval different from each other. The fluorescent display tube according to claim 11, wherein 13. The plurality of small area portions are a plurality of points or a plurality of lines parallel to each other.
Any of the fluorescent display tubes. 14. A third phosphor layer provided in contact with an outer peripheral edge of the first phosphor layer and generating visible light having a third wavelength different from the first wavelength and the second wavelength, The fluorescent display tube according to claim 1, wherein the second phosphor layer partially covers a boundary between the first phosphor layer and the third phosphor layer. 15. A visible light of a third wavelength, which covers a part of the remaining portion of the first phosphor layer not covered by the second phosphor layer and is different from the first wavelength and the second wavelength. 2. The fluorescent display tube according to claim 1, further comprising a third phosphor layer to be formed. 16. The method according to claim 1, further comprising a third phosphor layer that covers a part of the second phosphor layer and generates visible light having a third wavelength different from the first wavelength and the second wavelength. Fluorescent display tube. 17. The planar shape of a portion of the second phosphor layer on which the third phosphor layer is laminated has a dimension larger than a planar shape of the third phosphor layer by a predetermined value or more. 17. The fluorescent display tube according to claim 16, wherein: 18. A part of the predetermined shape is the first shape.
2. The fluorescent display tube according to claim 1, wherein the fluorescent display tube has a shape protruding from the phosphor layer. 19. The fluorescent display tube according to claim 1, wherein the predetermined shape has the same shape as the first phosphor layer.