JPS61183848A - Multicolor fluorescent character display tube - Google Patents

Abstract

PURPOSE:To produce a multicolor fluorescent display tube which emits several colors according to the operation condition by forming a phosphor by performing low resistance treatment on a zinc-sulfide-system or zinc-cadmium-sulfide-system phosphor activated by manganese and a metal other than manganese. CONSTITUTION:Either a zinc-sulfide-system phosphor such as ZnS or a zinc- cadmium-sulfide-system phosphor is activated by manganese and a metal other than manganese such as Ag and the resistance of the phosphor is reduced by a compound such as indium oxide to prepare a phosphor which emits light when low-velocity electron rays bump against it. After that, this phosphor is applied to an anode by printing, thereby making a fluorescent character display tube. In this fluorescent display tube, either the voltage or the current density of the anode is varied to produce two bands of luminous spectrum. The luminous color of the fluorescent character display tube can be varied by varying excitation condition. Consequently, it is possible to easily produce a multicolor fluorescent character display tube having stable luminous color.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a multicolor fluorescent display tube that can emit light in a plurality of colors among fluorescent display tubes.

[Conventional technology]

Generally, multicolor fluorescent display tubes are manufactured by coating phosphors of different emission colors on separate anodes, but with this method, the number of anodes increases as the number of emission colors increases, making it difficult to manufacture substrates. It will also be difficult to display high-definition multicolor displays. For this reason, the Special Publication No. 58-8547 or the Utility Publication No. 57-53410
It has been proposed that a phosphor layer is formed by mixing a plurality of types of phosphors with different emission colors, and the emission color is selected by selecting driving conditions, as shown in FIG.

[Problem that the invention seeks to solve]

However, since such conventional fluorescent display tubes contain a mixture of multiple types of phosphors, they have the following problems.

a. Since the lifespan varies depending on the type of phosphor, color shifts occur due to changes over time.

b. If the phosphors are insufficiently mixed, the ratio of each phosphor located on the surface side of the phosphor layer will not be constant. - Since a fluorescent display tube uses a low-speed electron beam, only the phosphors located on the surface side are excited, making it impossible to obtain the desired emission color.

Even if the weight ratio of the C1 phosphor is constant, a constant luminescent color cannot be obtained due to variations in particle size and luminescent properties.

d. When sulfide-based phosphors and oxide-based phosphors are mixed, they react with each other during the heat treatment during the tube-making process, resulting in a decrease in brightness and a change in the color of the emitted light. It may be stored away.

[Elaborate means to solve problems]

In order to solve such problems, the present invention constructs a display segment using a phosphor activated with a plurality of metal elements, which emits light by collision with a low-velocity electron beam.

[Effect]

The color of the emitted light is determined by the voltage or current density supplied to the phosphor.

〔Example〕

A phosphor made of znS is activated with Ag and Mn and has a low resistance made with indium oxide. At this time, the activation amount of Ag is 10-'
The activation amount of r/P and Mn is 1c1:2f/f.

In addition, 20% by weight of indium oxide is mixed in to lower the resistance.

The thus prepared phosphor was printed and coated on the anode to form a fluorescent display tube, and the grid voltage and filament were adjusted so that the anode current density was 1 mAZ-! When the voltage is controlled and the change in the emission spectrum with respect to the anode voltage Eb is determined, the result is as shown in FIG. As can be seen from this figure, there is a peak due to Ag near a wavelength of 450 nm, and a peak due to Ag at a wavelength of 585 nm.
A characteristic having two types of peaks, one due to Mn in the vicinity, is obtained. Among these, A near wavelength 45Qnm
The peak due to g shows a substantially linear intensity change with respect to changes in the anode voltage, but the peak due to Mn near a wavelength of 585 nm shows remarkable brightness saturation characteristics. This indicates that as the anode voltage increases, the blue light emitted by Ag near 450 nm becomes relatively stronger. In addition,
In FIG. 1, the characteristic al b.

The anode voltages of c, d, and e are IOV and 20V, respectively.

Represents 40V, 60V, and 80V.

FIG. 2 shows how the color of the light emitted at 9 o'clock changes when the voltage is changed in this way. In FIG. 2, the anode voltages are 20 V, 40 V, and 60 V given by symbols b to ekllL1.

80V, and as can be seen from this figure, as the voltage increases, the emitted light color shifts from the red color indicated by symbol R to the fruit and vegetable color indicated by symbol B.

In FIG. 2, symbols c, d, and e are colored dark orange, pale orange, yellowish pink, and pink, respectively.

Figures 3 and 4 show the characteristics when the anode voltage is fixed at 20 volts and the anode current is varied by controlling the grid voltage, and symbols a, b, c, d, e, and f are the currents, respectively. Density 0
．． 5 mAZa4.1 mAZi, 2mA/i.

Characteristics at 3 mA/i, 5 mA/aA, 7 mAZcA, and the emission colors when symbols are s, c, d, e, f are dark orange, slightly pale orange, pale orange, and whitish orange-yellow light.・It becomes pink.

Note that the above shows an effect similar to that of adding Ag and Mn as luminescent centers. The same applies to the znCdS-based phosphor.

〔Effect of the invention〕

As explained above, in this invention, since the phosphor is activated with two types of gold layers, the emission spectrum can have two emission bands, and the rate of change in the emission intensity of each is different from that of the anode. Since it changes depending on both the voltage and the anode current density, the color of the emitted light can be changed by changing these excitation conditions, and it has the effect of eliminating the drawbacks of the conventional method.

[Brief explanation of drawings]

Figure 1 is a graph showing the emission spectrum when changing the anode voltage, Figure 2 is a graph showing the emission color at this time, and Figure 3 is a graph showing the emission color at this time.
The figure is a graph showing the emission spectrum when the current density is changed, and FIG. 4 is a graph showing the emission color at this time.

Claims (1)

[Claims] A phosphor that emits light by collision with a low-speed electron beam is a zinc sulfide-based or zinc sulfide-cadmium sulfide-based phosphor activated with manganese and a metal other than manganese that has been treated to lower its resistance. A multicolor fluorescent display tube was used.