JPS5816134Y2 - fluorescent display tube - Google Patents

Description

[Detailed description of the invention] This invention relates to a phosphor display tube, in particular a type in which the light emitted from a phosphor layer is observed from the other side of a transparent substrate with an anode formed on one side. This invention relates to a fluorescent display tube.

Fluorescent display tubes display characters, figures, etc. by selectively projecting electrons emitted from a heated cathode onto an anode coated with a phosphor. Furthermore, since it has features such as being able to be driven at a low voltage and having low power consumption, it is often used as a display device for electronic devices and the like.

By the way, there are two types of optical display tubes: one is a type that is formed on an insulating substrate and the light emitted from the anode portion with a phosphor layer adhered to the top surface is observed through the grid, cathode, and windshield, and the other is the type that uses the substrate as a substrate. There is a type in which a transparent substrate is used, and the electrode forming the anode portion is formed of a transparent conductive film, and the light emission from the phosphor layer is observed from the transparent substrate side.

The former has the disadvantage that unnecessary electrode parts are visible to the observer due to its structure, and the shoulder of the windshield becomes an obstacle, limiting the viewing angle. There is a problem that the viewing angle is narrow because it is restricted by the holding frame.

In particular, in the case of multi-dot matrix type display tubes, which have a tetrode structure that has a grid for selecting rows or columns of dots and a grid for selecting display digits, the overlapping of the two grids makes it difficult to adjust the viewing angle. There was a problem in that the transmittance of light emitted from the phosphor layer was different.

Furthermore, when a filter is used to make internal structures such as grids invisible, there is a problem in that the brightness becomes extremely low.

In addition, in the case of the latter, which is observed from the transparent substrate side, the light emitted from the phosphor layer in the opposite direction to the observation side is reflected by the background grid of the phosphor, the inner surface of the windshield, etc. There is a problem in that it enters the observer's eyes through the transparent electrode or transparent substrate, lowering the contrast and causing poor visibility.

In general, in fluorescent display tubes that use slow electron beam excitation,
Since only the very thin surface of the phosphor layer emits light, the second type mentioned above, which is observed from the transparent substrate side, allows the light emission from the surface of the phosphor layer to be easily observed from the back side. In order to achieve this, it is necessary to make the phosphor layer very thin (for example, to make it transparent).

For this reason, the light from the emitting phosphor layer is reflected inside the fluorescent display tube and leaks to the observation side on the back side of the non-emitting phosphor layer, causing even more light to emit from the emitting phosphor layer. with a non-emissive phosphor layer;
There was a problem in that the contrast was reduced.

This invention was made in view of the above points,
In a phosphor display tube in which the light emitted from a phosphor layer is observed from the anode section or the other side of an insulating transparent substrate formed on one side, the anode section of the insulating transparent substrate is formed on one side of the phosphor layer. A semi-transparent or opaque insulating film is formed on the surface where the phosphor layer is formed using the adhered portion of the phosphor layer as an opening, and the light-emitting upper surface of the phosphor layer is placed inside the opening. The purpose of the present invention is to solve the above-mentioned conventional problems and to provide a luminous light display tube with good contrast, excellent visibility, and sufficient brightness. It is something to do.

The present invention will be explained in detail below using the drawings.

FIG. 1 is a sectional view showing a first embodiment of a fluorescent display tube according to the present invention.

In the figure, reference numeral 1 denotes an insulating transparent substrate made of glass, for example. On one side of this substrate 1, a pattern of a transparent conductive film 2 that is divided into segments according to the number of segments and becomes an anode conductor is formed. A segment-shaped transparent electrode portion 2 is formed on the surface of the substrate 1 on which the transparent conductive film 2 is formed.
A translucent or opaque insulating film 3 is formed by leaving a portion corresponding to a as an opening.

Furthermore, a phosphor layer 4 is thinly deposited on the segment-shaped transparent electrode portion 2a in the opening where the insulating film 3 is not deposited to form an anode portion. The light-emitting upper surface of the insulating film 3 is formed at a lower position than the upper surface of the opening periphery of the insulating film 3.

Further, a transparent conductive film 2 covered with the above-mentioned insulating film 3
is the terminal connection part 2b of the external terminal 11 as the lead wire 2c.
has been derived.

Further, the insulating film 3 is coated with a conductive film 5 to prevent charging, if necessary.

A grid 6 is electrically connected to a predetermined transparent conductive film 2 through a through hole (not shown) formed in the insulating film 3 on the side of the substrate 1 having the above structure having the phosphor layer 4. and a cathode 7 are arranged, and the grid 6 and cathode 7 are housed in a vacuum-tight envelope 9 formed by the substrate 1 and the rear container 8.

A conductive film 10 is coated on the inner surface of the vacuum-tight envelope 9 facing the cathode 7 and the grid 6, that is, the inner surface of the rear container 8, for preventing static electricity and preventing the influence of external electric fields. 10 is electrically connected to the cathode 7, electrically connected to the grid 6, or separately led out to an external terminal by a lead wire 2c, and connected between the cathode potential and the anode potential. An appropriate potential may be applied.

Further, the grid 6, cathode 7, and transparent electrode portion 2a are connected to an external terminal 11 via a lead wire 2c formed by extending the transparent conductive film 2.

By the way, if the conductive film 10 is formed of a light-absorbing material, for example, a black conductive film such as graphite, the light emitted from the phosphor layer 4 emitted toward the rear container 8 side will be absorbed by the conductive film 10. This prevents the problem that the emitted light is reflected by the conductive film 10 and irradiates the non-emitting anode portion, resulting in a decrease in contrast between the non-emitting anode portion and the emitting anode portion.

By the way, various methods can be considered as a method for forming the anode section, but for example, in this embodiment, the method shown in FIGS. 2 and 3 is used.
The figure shows a plan view and a cutaway end view of the main part taken along line 2--2 in FIG.

2 and 3 show a negative digit pattern display section, and show an example in which external terminals are connected to each anode section within the envelope.

That is, first, on the substrate 1, a pattern of the transparent conductive film 2 divided according to the number of segments is formed as shown by broken lines in the figure.

The pattern may be formed by depositing the transparent conductive film 2 on the entire surface of the substrate 1 and then removing unnecessary portions using a photolithography method, or by depositing the transparent conductive film 2 on the substrate 1 using a mask evaporation method. The transparent conductive film 2 may be directly deposited in accordance with a required pattern.

Next, on the substrate 1 on which the pattern of the transparent conductive film 2 is formed, a transparent electrode part 2a and a terminal connection part 2b corresponding to the segment shape are left, and an insulating film 3 is formed, for example, with the main component being low melting point flint glass. Depending on the material, it is applied by screen printing and formed by firing.

In this case, a pigment is mixed into the material that will become the insulating film 3 to color it so that the insulating film 3 becomes optically translucent or opaque.

The color of the insulating film 3 may be any color as long as it is semitransparent or opaque, but it is preferably the same color as the phosphor layer 1 to be deposited in the next step.
It is best to use a color similar to the color when the light is not emitting light.

Next, the transparent electrode part 2 which is not covered with the insulating film 3
A phosphor layer 4 is applied to the segment a.

The deposition method can be any method such as precipitation, screen printing, electrodeposition, etc. In this case, the thickness of the phosphor layer 4 to be deposited is determined so that the emitted light Phosphor layer 4
It is preferable that it be as thin as possible, since it will be taken out to the outside through.

For example, a silver paste is applied to the terminal connecting portion 2b in order to improve contact with the external terminal 11, and then baked.

After that, the grid 6, cathode 7, back container 8, etc. can be attached using the commonly used procedures.

When an external power source is connected to the fluorescent display tube constructed in this manner, electrons emitted from the cathode 7 impinge on the phosphor layer 4, causing the phosphor layer 4 to emit light.

The luminescent layer 4 and the transparent electrode section 2 emit light from the fluorescent layer 4.
The light that passes through a and the substrate 1 and is perceived by the observer, and that is emitted by the phosphor layer 4 toward the inside, that is, toward the grid 6, is absorbed by the conductive film 10 and the insulating film 3. become.

This eliminates the risk of light leaking to the anode portion that is not emitting light and being perceived.

In the first embodiment described above, the lead wire 2c is formed of the transparent conductive film 2, but the transparent conductive film 2 has a problem in that the electrical resistance is about one to three orders of magnitude higher than that of the metal film. In particular, when the transparent conductive film 2 is used as the lead wire 2c for dynamic driving, the voltage drop becomes large, which may cause variations in brightness between segments or between displays.

In order to prevent this, for example, the following second to sixth embodiments may be adopted.

Here, the second and third parts of the fluorescent display tube according to this invention will be described. The fourth embodiment is shown in FIGS. 4 and 5, respectively.

FIG. 6 will be explained.

Note that each of these embodiments is the same as the first embodiment described above except for the wiring pattern of the lead wires, so only the wiring pattern will be described here.

The second embodiment shown in FIG. 4 has a structure in which a metal film is deposited on the substrate 1 as a lead wire 20c, and a transparent electrode portion on which the phosphor layer 1 is deposited by the lead wire 20c. 2
a and the terminal connection portion 2b are connected.

The third embodiment shown in FIG. 5 shows an example of a wiring pattern used for dynamic driving, and the transparent electrode 2a to which the phosphor layer 4 is attached is enlarged as much as space allows. , the enlarged portion is a wide lead wire 2c.

Further, the wide lead wire 2c is connected to the wide lead wire 2c of the transparent electrode portion 2a constituting the corresponding segment of the adjacent display digit and the narrow lead wire 20c made of metal film.
connected by.

In the second and third embodiments, in order for the lead wire 20c to be visually buried in the insulating layer deposited thereon, a pigment is mixed into the lead wire or the insulating layer.
It is preferable that the colors of the two be similar.

The fourth embodiment shown in FIG. 6 shows an example of a wiring pattern used for dynamic drive, similar to the third embodiment, and includes a transparent electrode on which a phosphor layer 4 is attached. The portion 2a is connected to a first lead wire 20e made of a metal film, and this first lead wire 20c is connected to the first lead wire 20e.
It is connected via a through hole 22 to a second lead wire 21c of a metal film formed on an insulating film covering 0c.

The transparent electrode portions 2a constituting corresponding segments of adjacent display columns are connected in common by this second glue line 21c.

The second point mentioned above. Third. The metal film used in the fourth embodiment is formed by depositing, for example, silver paste and firing it.

In addition, the present invention is not limited to the embodiments described above and shown in the drawings, but can be implemented with various modifications without changing the gist of the invention. Various modifications can be made, such as polymerizing grids with a grid and extending the spacers to the outside to form lead wires.

As described above, the fluorescent display tube according to the present invention is a fluorescent display tube in which the display is observed from the other side of the insulating transparent substrate with the display section formed on one side. On the surface of the transparent substrate on which the phosphor layer is attached, a translucent or opaque insulating film is deposited on the other parts except for the phosphor layer, so that grids, etc. The internal structure of the phosphor layer is completely invisible, a clear display is obtained, the contrast of the luminescent segment against the background is improved, and if the insulating film is made of a color similar to that of the phosphor layer, the luminescent segment and the non-luminescent segment can be clearly displayed. The contrast with the segments is also improved, and visibility is greatly improved, which is an excellent practical effect.

In addition, since the internal structure is not visible, there is no need for a filter to hide the internal structure, so there is no risk of reducing brightness, and an excellent fluorescent display tube with sufficient brightness can be provided. It is effective.

Furthermore, since there is no grid or the like intervening between the display section and the viewer, the effect of enlarging the viewing angle is extremely significant.

Furthermore, according to the present invention, since the internal structure is hidden, intermediate supports etc. for reinforcing the vacuum-tight envelope can be arbitrarily used as long as the electrical characteristics are not impaired. It has the advantage of being able to realize a larger optical display tube at a lower cost, and the effects obtained are outstanding.

In addition, in the present invention, if a lead wire with good conductivity, which is different from the material of the transparent electrode, is used as a means for supplying electricity to the transparent electrode, uneven light emission can be prevented even when using Guinamink drive. occurs.

Further, according to the fluorescent display tube according to the present invention, in which the display is observed from the other side of the insulating transparent substrate on which the display portion is formed on one side, the translucent or opaque insulating coating is Since the light-emitting upper surface of the phosphor layer deposited in the opening of the phosphor layer was formed at a position seven steps lower than the recess of the phosphor layer, the phosphor layer Not only is it possible to effectively prevent the emitted light from being diffused to other parts, making it possible to obtain a clear and easy-to-see light emitting display, but also the diffusion and wraparound of this emitted light prevents the emitted light from being emitted from other non-lit phosphor layers. This type of fluorescent display tube has excellent effects in that there is almost no leakage of light and the contrast between the light-emitting phosphor layer and the non-light-emitting phosphor layer is improved.

Furthermore, since the recessed opening is formed by forming the insulating film thicker than the phosphor layer, its manufacture is extremely easy and efficient, and it can also be effectively formed on a glass substrate. There is a possible effect.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a first embodiment of a fluorescent display tube according to the present invention, FIG. Figure 3 is a cutaway end view of the main part along the line ■-■ in Figure 2, Figures 4 and 5,
Figure 6 is 2. 3. It is a pattern explanatory diagram showing the wiring pattern according to the fourth embodiment. 1...Substrate, 2a...Transparent electrode part, 2
c... Lead wire, 3... Insulating film, 4
... Luminescent layer, 7 ... Cathode, 9 ...
...Vacuum-tight envelope.

Claims (4)

[Scope of utility model registration request] (1) On one surface of a transparent insulating substrate, a transparent electrode portion made of a transparent conductive film with a phosphor layer adhered to the upper surface according to the display pattern is formed, and this transparent electrode portion By applying a display signal to the phosphor layer through a current-carrying means formed on the substrate, the electrons emitted from the heated cathode are bombarded to cause the phosphor layer to emit light. In a fluorescent display tube in which the light emission of the phosphor is observed from the other side of the substrate, one surface of the substrate corresponds to the transparent electrode portion on which the phosphor layer is adhered. A translucent or opaque insulating film is deposited on the opening.
The upper surface of the phosphor layer on the cathode side in the opening is recessed one step lower than the upper surface of the insulating film on the cathode side at least at the periphery of the opening. A bright light display tube. (2) The fluorescent display tube according to claim 1, wherein the insulating film has a color similar to that of the phosphor layer. (3) The means for supplying electricity to the transparent electrode section includes lead wires, at least two of which are made of the same material as the material from which the transparent electrode section is formed. Fluorescent display tube as described. (4) The fluorescent display tube according to claim 1 or 2, wherein the means for supplying electricity to the transparent electrode portion is a lead wire made of a material different from the material from which the transparent electrode portion is formed. .