JPS5941669B2 - Slow electron beam excited phosphor and fluorescent display device using this slow electron beam excited phosphor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a low-speed electron beam-excited phosphor that emits light upon bombardment of electrons with a low grain velocity voltage of several V to several tens of V, and a low-speed electron beam-excited phosphor that uses this low-speed electron beam-excited phosphor. This invention relates to a fluorescent display device.

In recent years, fluorescent display devices have come into widespread use as display devices for various electronic and electrical devices, as they can be driven at low voltages, consume little power, and provide bright, easy-to-read displays. I'm getting used to it.

This fluorescent display device causes electrons from a filament-shaped cathode, which emits electrons when heated with electricity, to strike an anode that has a phosphor layer deposited on its top surface and selectively applies a positive anode voltage. The phosphor layer coated on the anode is a phosphor layer that can provide sufficient luminance to display characters and figures at a low hull velocity voltage. It is composed of a light body, a so-called slow electron beam excited phosphor.

Incidentally, as a low-speed electron beam-excited phosphor for this fluorescent display device, a ZoO:ZΠ-based phosphor has conventionally been used.

This ZnO:Zn-based phosphor has a luminescence threshold voltage,
The so-called dead voltage is extremely low at 1 to 2V.
In addition, in general, sufficient luminance to obtain a display can be obtained with an anode voltage of about 10 to 20 V, so this ZnOZn-based phosphor is extremely excellent as a low-speed electron beam-excited phosphor. Since the luminous material emits light due to the impact of an electron beam is limited to greenish colors, this ZnO
:The luminescent color of a fluorescent display device using a Zn-based phosphor is limited to greenish colors.

On the other hand, as the field of application of fluorescent display devices expands, there is a growing demand from various fields for diversification of display emitted light colors. For example, when displaying a warning, a red display is preferable to green in order to obtain a warning effect. In addition, when multiple display objects are displayed using one or more fluorescent display devices, each display can be extremely easily read by changing the luminescent color of the display according to each display object. At the same time, there are advantages such as eliminating the possibility of misreading. ZuS:Ag, (
Cu, U), [ZnS:Y, (Cl, Al, Na), Y
is a rare earth element], CaS: Eu, ZnSe: Ga, Sr
S:Eu, caO:Smf) Ruiha [(Znl?XCd
x) S: M, (U, Cf), x=O~1, M is Ag, C
u? Efforts have been made to produce low-speed electron beams by applying various treatments to phosphors such as elements selected from the group of Au.

Here, the present inventor conducted various experiments regarding the following points in an attempt to produce a new phosphor for slow electron beam excitation. For example, (1) the various phosphors mentioned above can be mixed with conductive or semiconductive metal oxides such as In2O3, snO2, and znO to lower the resistance of the phosphor, and can be used for low-speed electron beam excitation. (2) ZnS
(3) Applying Zn or Cd treatment to a (ZnCd)S-based phosphor to lower the resistance of the phosphor itself and make it a slow electron beam-excited phosphor, such as (3) SnO2-based phosphor. ,
For example, the phosphor is constructed using a low-resistance material in advance as a matrix for the phosphor. However, in the case of (1) above, for example, in order to lower the resistance value of the phosphor to the point where it is suitable for slow electron beam excitation, the mixing ratio of the metal oxides to be mixed must be extremely high, 30% to 5070%. This not only reduces the light emitting area of the phosphor itself, but also makes it difficult to efficiently and uniformly emit light over the entire phosphor surface. Since the phosphor is expensive, there is a problem in that the cost of the phosphor itself is also high.

In the case of (2), although it is a novel method according to the invention of the present inventor, it is difficult to reduce the resistance value of the phosphor itself sufficiently by Zn or Cd treatment alone, and therefore However, the dead voltage is high, and sufficient luminance cannot be obtained in a low voltage region of, for example, 20 V or less.

Furthermore, in case (3), although the dead voltage is low, the brightness does not extend well with respect to the anode voltage, and sufficient practical brightness cannot be obtained.

The present invention relates to the improvement of method (2) by the present inventors described above, and involves applying Zn treatment and C
After lowering the resistance of the phosphor itself by applying d treatment, by mixing a conductive or semiconductive metal oxide with it, it can be used at a voltage of several volts to several tens of volts. The object of the present invention is to provide a low-speed electron beam-excited phosphor that emits light with sufficient brightness through accelerated low-speed electron beam excitation.

A further object of the present invention is to provide a fluorescent display device that uses the above-described low-speed electron beam excited phosphor to display in green and in colors other than green. DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a low-speed electron beam-excited phosphor and a fluorescent display device according to the present invention will be described below with reference to the drawings.

The low-speed electron beam-excited phosphor according to the present invention can be produced in two steps: as described above, the phosphor itself is made to have a low resistance, and the phosphor is mixed with a conductive or semiconductive metal oxide. It is obtained through the process.

First, in the processing step for reducing the resistance of the phosphor itself, the phosphor is doped with a metal forming the matrix of the phosphor as a processing material to reduce the resistance.

Specifically, as shown in FIG. 1, a phosphor 2 is housed in one end of a quartz tube 1, and a processing material 3 is put in the other end of the quartz tube 1, and the quartz tube 1 is Seal the exhaust.

The quartz tube 1 in which the phosphor 2 and the processing material 3 are vacuum-sealed is heated at a predetermined temperature for a predetermined period of time, and after firing the phosphor 2 in the atmosphere of the processing material 3, the quartz tube 1 is sealed in vacuum.
1 is rapidly cooled to lower the resistance of the phosphor itself.

Next, In2O was added to the phosphor powder obtained above.
3. A predetermined amount of conductive or semiconductive metal oxides such as snO2 and znO are mixed to form a phosphor excited by a slow electron beam.

Next, the low-speed electron beam-excited phosphor according to the present invention will be described in detail with reference to Examples.

First, it emits red light by electron beam excitation (Zn, Cd)
S: Ag, Af phosphor is used as a starting material.

The (Zn,Cd)S:Ag,U phosphor is Zn15
70, using (ZnO.l5cdO)S with 85% Cd as a matrix, adding 10-6 to 10-3 mol of Ag and the same mole of Al to 1 mol of this matrix, and firing at 80'C to 1000'C. That's what I got. However, this (Zn, Cd)S
:Ag,M phosphor is doped with Cd by baking it at a heating temperature of 800° C. to 1000° C. for 2 to 24 hours using Cd as a treatment material using the apparatus shown in FIG.

Next, 1 to 30 weight of N2O3? , for example, 15 weight?
Then, it is added to the Cd-treated phosphor and thoroughly mixed in an agate mortar to form a low-speed electron beam-excited phosphor. Next, the characteristics of the slow electron beam excited phosphor obtained as described above will be described. First, in order to investigate the characteristics of the above-described low-speed electron beam-excited phosphor, the present inventor created a fluorescent display device whose schematic configuration is shown in FIG. 2.

That is, a phosphor layer 1 made of the above-mentioned slow electron beam excited phosphor is placed inside a vacuum envelope 11 having a transparent display window.
A filament-shaped cathode 14 is provided facing the anode 13 and emits electrons by heating with electricity. It has a configuration in which a mesh-shaped control electrode 15 for performing acceleration and control is provided. Furthermore, external terminals 16 are connected from each electrode to the outside of the vacuum envelope 11 in a vacuum-tight manner.
The thermal voltage Ef is applied to the cathode 14, and the control electrode 1 is
5 is applied with a control voltage Ec, and the anode 13 is applied with an anode voltage Eb.

Therefore, the anode voltage Ed of the slow electron beam excited phosphor according to the present invention measured by the fluorescent display device shown in FIG.
FIG. 3 shows the characteristics of luminance L with respect to the luminance.

In FIG. 3, the horizontal axis shows the anode voltage Eb, and the vertical axis shows the relative brightness at each anode voltage, and curve 2 shown by the solid line shows the characteristics of the slow electron beam excited phosphor of the present invention, and the broken line shows the characteristics of the slow electron beam excited phosphor of the present invention. The curve E shown by ``E'' and the curve shown by a dashed-dotted line are (Zn, Cd) S:Ag, A, which are not subjected to any treatment.
'(Zn,Cd)S with only phosphor and Cd treatment
:Characteristics of Ag phosphor.

As is clear from FIG. 3, the low-speed electron beam-excited phosphor according to the above embodiment of the present invention has a significantly reduced dead voltage of about 5V, and an anode voltage of 20V or less. The voltage Eb makes it possible to obtain red light emission brightness sufficient for display.

In this manner, according to the present invention, a slow electron beam-excited phosphor having an emission color of green or other than green can be obtained by changing the red color or the mixed crystal pressure.

Therefore, by using the low-speed electron beam-excited phosphor according to the present invention, it is possible to obtain a fluorescent display device that is extremely easy to see and can expand its display function. For example, the fourth
As shown in the figure, an analog display section is formed by linearly arranging anodes 21 coated with a phosphor layer formed of a slow electron beam excited phosphor obtained according to the present invention on a common substrate. 22, and an anode 24 having a phosphor layer made of a low-speed electron beam-excited phosphor according to the present invention on the upper surface thereof arranged in a Japanese character shape. By making the emitted light colors of the slow electron beam-excited phosphor deposited on the phosphors different, it becomes extremely easy for the observer to distinguish between the analog display section 22 and the digital display section 24, and an easy-to-read display can be obtained. Become.

Furthermore, the analog display section 22 is divided into two areas 22a and 2.
By dividing the light into two regions 22a and 22b and varying the emission color of the low-speed electron beam-excited phosphors deposited on the respective regions 22a and 22b, it is extremely effective to obtain, for example, a warning effect against excessive signals.

As described above, the present invention uses a phosphor as a starting material, which cannot obtain sufficient brightness for display with an electron beam accelerated by an accelerating voltage of several V to several tens of V, and uses this phosphor as a starting material. First, the metal constituting the matrix is doped to lower the resistance, and then In2O3, snO2, Zn
A low-speed electron beam-excited phosphor is prepared by mixing a conductive or semi-conductive metal oxide such as O, and this low-speed electron beam-excited phosphor is used to construct a fluorescent display device. .

Therefore, the slow electron beam excited phosphor according to the present invention is
Since the resistance has been sufficiently reduced, the dead portage is extremely low, on the order of a few volts. Furthermore, since the amount of metal oxide to be mixed is small, the luminous area of the phosphor decreases, and the luminous efficiency decreases. ZnO, which has been well known as a low-speed electron beam-excited phosphor, eliminates all problems such as light emission and uneven light emission:
It has the excellent advantage of being able to provide green phosphors and phosphors of various colors other than green, which have almost the same characteristics as Zn-based phosphors, and the effects obtained are extremely large.

Furthermore, since the low-speed electron beam-excited phosphor according to the present invention requires only a small amount of metal oxide to be mixed, it has an excellent effect of being inexpensive.

Further, the fluorescent display device according to the present invention constructed using the low-speed electron beam excited phosphor obtained according to the present invention can obtain a display portion having various luminescent colors with a low anode voltage, making the display extremely easy to see. In addition, the effects obtained are extremely large, such as expanding the display function and improving the warning effect.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an embodiment of an apparatus for manufacturing a slow electron beam-excited phosphor according to the present invention, and FIG. A schematic configuration diagram showing an example of the fluorescent display device used, FIG. 3 is a diagram showing the characteristics of the low-speed electron beam excited phosphor according to the present invention, and FIG. 4 is a diagram showing the display section of the fluorescent display device according to the present invention. It is a figure showing an example. 1...quartz tube, 2...phosphor, 3.
... Processing material, 12 ... Phosphor layer, 1
3...Anode, 14...Cathode, 21,2
3... Anode.

Claims (1)

[Claims] 1 (Zn, Cd)S:Ag, Al phosphor powder doped with a metal constituting the matrix of the phosphor to lower resistance, conductive or semiconductive. A phosphor that is excited by a slow electron beam and is characterized by being made of a mixture of metal oxides. 2. In a fluorescent display device that obtains a display by causing electrons emitted from a filament-shaped cathode to strike an anode having a phosphor layer on its upper surface to excite the phosphor layer and emit light, The light layer is (Zn, Cd)S:Ag, Al
It is composed of a phosphor made by mixing a conductive or semiconductive metal oxide with a phosphor powder that has been doped with a metal that constitutes the matrix of the phosphor to lower its resistance. A fluorescent display device characterized by: