JPS5821946B2 - Multicolor luminescent powder phosphor and fluorescent display tube using it - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multicolor light-emitting powder phosphor and a fluorescent display tube using the same. By using this, the emitted color of one character segment can be changed by controlling the signal by changing the magnitude of the character signal voltage or character signal current density, and it is possible to display a multicolor display. The aim is to provide a fluorescent display tube that can

Conventionally, as a high-efficiency phosphor based on slow electron beam excitation (5 to 5 oeV), only a ZnO:Zn phosphor that emits green light has been used.

This phosphor emits light when excited by a slow electron beam of about 5 eV.

This ZnO: 1 to 10 by taking advantage of the characteristics of Zn phosphor.
It is used not only as a phosphor for cathode ray tubes that emit light using KeV high-speed electron beams, but also for character display tubes that operate using low-speed electron beams.

The character display tube extracts electrons from the hot cathode and generates 20 to 25
Acceleration energy of eV is applied to the phosphor to excite it to emit light, or plasma electrons generated by gas discharge are used to cause the phosphor to emit light.

Recently, it has become popular to control systems by combining microcomputers and sensing devices.
It has come to be applied to a wide variety of systems, including cooking appliances such as microwave ovens and regular ovens, air conditioning equipment such as room air conditioners, and home appliances such as washing machines and dryers. .

In such system control, a display system is one of the essential elements.

In these cases, character displays such as timer displays, level displays, and various operation displays are required.

These character displays using fluorescent display tubes are all made of ZnO.
: This is simply done by utilizing the green light emitted by the Zn phosphor.

For example, in a microwave oven, when the fluorescent display tube is operated as a timer, it is generally configured to display the normal time and the operating time indicating the start and end of cooking.

Even in such applications, if the former time display and the latter time display can be displayed in different colors,
It is very easy to understand and is a very distinctive display system.

In addition, in the field of recent audio equipment, sound range level display,
Tuning displays are performed, and the former level display includes, for example, color-based determination of safe areas and dangerous areas;
In the latter tuning display, a multicolor display is preferable, for example, for distinguishing between AM and FM.

Furthermore, it would be extremely convenient if the display of oil level, temperature, speed, mileage, etc. of an automobile could be similarly displayed in multiple colors.

Despite these many needs, a fluorescent display tube using a slow electron beam-excited phosphor has not been realized.

This is because, other than ZnO:Zn phosphor, there is no phosphor that can efficiently emit light with low-speed electron beams and emit light in colors other than green, and with the increasing number of colors, the number of electrode parts and lead terminals, etc. This is due to reasons such as an increase in image quality or a decrease in sharpness.

Recently developed display systems other than fluorescent display tubes include light emitting diodes and liquid crystals, but each has major drawbacks.

When using light emitting diodes to display dots, the dots themselves are large and are quite difficult to read.

Furthermore, since liquid crystals do not emit light by themselves, they are subject to restrictions on usage conditions.

On the other hand, in magnetic optical display tubes, a finely powdered phosphor paste is applied using a printing method, so letters, numbers, lines, picture elements, etc. can be arranged arbitrarily and clearly. O is an excellent display system that is easy to see. Based on this background, the inventors focused on the multicolor display system of fluorescent display devices, and developed a phosphor with high luminous efficiency by low-speed electron beam excitation and a simple method. We have been studying the multicolor luminescence method.

As a result, the inventors found that approximately 590
We have developed a new phosphor for low-speed electron beams that emits red-orange light with a maximum emission peak at a wavelength of nm.

It has been revealed that the 5n02:,Eu phosphor emits light at a voltage of 5V, similar to the ZnO:Zn phosphor, and has a high luminous efficiency of 5 to 7V.

In addition to ZnO: Zn phosphor and 5n02: Eu phosphor, Zn2 is a phosphor that emits light at a relatively low voltage.
SiO4: Mn phosphors are known.

This is a phosphor that emits green light with a high degree of saturation, and the threshold voltage for its light emission is approximately 300V.

However, Zn25io4:Mn phosphor and ZnO:Z
In a mixture with the n fluorophore or the 5n02:Eu fluorophore, the Zn2Ss04:Mn fluorophore begins to emit light at about 30V.

Zn2 SiO,: Mn phosphor and 5n02: Eu
The inventors have discovered that in a mixed phosphor with a phosphor, the emission color can be changed to red-orange, yellow, or yellow-green depending on the excitation voltage or excitation current density.

When this phosphor is used to form the fluorescent surface of a fluorescent display tube, it has the following characteristics.

(1) Multicolor display and color changes can be easily realized,
You can also get neutral colors.

(2) Since a mixed phosphor is coated on the same electrode instead of coating each phosphor separately, the drawback of an increased number of terminals in the display tube is eliminated.

(3) It is very easy to manufacture the phosphor and the display tube using it, and there is no need to change conventional methods.

(4) The display is easy to see because it is displayed in character segments instead of dots.

(5) Since multicolor display can be performed, the amount of displayed information increases.

(6) Not only character display, but also color display of character display and graphic display can be made clear.

Next, the multicolor luminescent powder phosphor of the present invention will be explained.

5n02: Eu phosphor and Zn2SiO,:
It is desirable to use a Mn phosphor having a particle size of 0.1 to 10 μm.

When the particle size becomes larger than 10 μm, Zn2 SiO,
: Causes charging of the Mn phosphor and non-uniform light emission.

Even if it is attempted to obtain a phosphor with a particle size smaller than 0.1 μm and good crystallinity, it is difficult to manufacture and impractical.

Z n 2 S t 04 with a particle size of 1 to 3 μm: M
n phosphor and SnO2:Eu with a particle size of 0.2 to 1.0 μm
When using a phosphor, as is clear from the table above, Sn
O2:Eu/Zn25i04:The color of the emitted light can be changed by changing the excitation voltage when the weight ratio of Mn is in the range of 5 or less and 0.2 or more.

When the particle size of each phosphor is changed, the color of the emitted light changes somewhat because the surface area changes.

For example, when the particle size of the 5n02: Eu phosphor becomes smaller, the emission color shows a somewhat more demarcated emission color than the emission color shown in the table above, and when the particle size of the Zn2 Si04: Mn phosphor becomes smaller. , the luminescent color is slightly greener than the luminescent color shown in the table above.

Similar effects were also obtained by changing the excitation current density.

This is because the luminance of Zn2SiO4:Mn increases linearly with increasing voltage and current density, whereas with Sn
This is because the luminance of O2:Eu does not increase linearly and tends to be saturated.

FIGS. 1 and 2 show an embodiment of a hot cathode multicolor fluorescent display tube using the phosphor according to the present invention.

In the figure, 1 is a transparent glass envelope, and a filament-shaped hot cathode 2 is arranged at the front end of the envelope.
A mesh-like control grid 3 is arranged behind the cathode 2 .

Behind the control grid 3, a plurality of character segment electrodes 5 whose surfaces are coated with a phosphor 4 are arranged insulated from each other on a support substrate 6.

This phosphor 4 is made of, for example, SnO□:Eu/Zn2Si.
It is mixed at a weight ratio of O4:Mn=1, and 5
n02: Eu phosphor and Zn2 Si04:
The particle sizes of the M n phosphors are 0.2-1.0 μm and 1-3 μm, respectively.

A plurality of lead wires 7 are provided hermetically passing through the container 1 and are connected to each of the electrodes 5 inside the container 1.

This is almost the same as the electrode arrangement of conventional thermionic fluorescent display tubes, and the SnO□:Eu phosphor and Zn
2 SiQ4: The difference is that the fluorescent film is made of Mn phosphor.

In the above multicolor fluorescent display tube, the cathode 2 is energized by applying a voltage of 3 to 5 cm to generate heat, and the control grid 3
For example, a voltage of 20V is applied to.

By selectively applying voltage to the character segment electrodes 5, characters can be displayed.

When the voltage applied to the character segment electrode 5 is 20V, it emits red-orange light, when it is 40V, it emits yellow light, and when it is 70 V or more, it emits yellow-green light.

Also, when the voltage applied to the character segment is 70V,
When the voltage applied to the control grid is changed to change the density of the current flowing through the character segment, the character segments can emit red-orange light when the current density is low, and yellow-green light when the current density is high.

As described above, the phosphor according to the present invention has a wide range of applications because the color of the emitted light can be changed depending on the excitation energy, and because it emits light using a slow electron beam.

The fluorescent display tube according to the present invention has the same number of terminals as a monochromatic fluorescent display tube, and can emit various colors simply by controlling the signals to the character segment electrodes.
This has the advantage that the display function is greatly improved without complicating the structure.

Furthermore, since the drive voltage is low, the structure of the drive circuit is simplified, and the range of applications is expected to be expanded.

In addition to the slow thermoelectrons mentioned above, electrons from plasmas such as helium, neon, argon, and hydrogen can also be used for light emission.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view showing the structure of an embodiment of a fluorescent display tube according to the present invention, and FIG. 2 is a sectional view of the same. 1... Glass container, 2... Hot cathode, 3
... Control grid, 4 ... Fluorescent material, 5
. . . Character segment electrode, 6 . . . Support substrate, 7 . . . Lead wire.

Claims (1)

[Claims] 1 Europium activated tin oxide (S, nO□: Eu)
Phosphor and manganese-activated zinc silicate (Zn2Sin4:M
n) A mixture with a phosphor, the mixing weight ratio of which is 5.
≧SnO□: Eu / Zn25 io4: Mn≧
1. A multicolor luminescent powder phosphor characterized in that the luminescent luminescence is within the range of 0.2. 2. The multicolor light-emitting powder phosphor according to claim 1, wherein the phosphor particles have a particle size of 0.1 to 10 μm. 3 Europium-activated tin oxide (Sn02: Su) phosphor and manganese-activated zinc silicate (Zn2Sin4:Mn)
A mixture with a fluorescent material, the mixing weight ratio of which is 5≧5
n02: Eu/Zn2 Si04: Mn≧0
．． A fluorescent film is formed by attaching a multicolor light-emitting powder phosphor falling within the range of 2 to a character segment electrode, and by controlling a signal applied to the character segment electrode, A fluorescent display tube characterized in that it is configured so that the color of the emitted light is variable.