JPH01264130A - Cathode body structure - Google Patents

Abstract

PURPOSE:To nearly unify the operating temperature of three substrate metals and suppress the change of the color tone during operation by making the resistance value of a lead wire connecting heating elements on both sides and heater terminals larger than the resistance value of a lead wire connecting the heating elements together. CONSTITUTION:The resistance value of a lead wire 5e connecting heating elements 5a and 5c on both sides among three heating elements 5a-5c arranged linearly and heater terminals is made larger than the resistance value of a lead wire 5d connecting the heating elements 5a-5c together. Since the resistance value of the lead wire 5e is increased, the resistance value of this ribbon portion is increased, the heat quantity of this portion is increased, the heat conduction loss can be reduced. The operating temperature of the center substrate metal can be made nearly equal to the operating temperature of the substrate metals on both sides, the change of the color tone can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laminated cathode structure used in an in-line color cathode ray tube.

(Prior art) Figs. 3 to 5 are enlarged plan views of a conventional cathode structure of this type. Fig. 3 is a plan view of the side where electron emission occurs, and Fig. 4
The figure is a plan view of the heating side, and FIG. 5 is a side sectional view. In each figure, 1 is a heat-resistant insulating substrate, for example 0.1 to 0.4
It is made of alumina, etc., about the thickness of a cabinet. 28~2c
is a base metal arranged in a straight line, and nickel containing a trace amount of a reducing impurity element is deposited on one side of the heat-resistant insulating substrate 1 by a method such as vacuum evaporation or sputtering. 4 is, for example, (Ba-Sr.Ca)O
It is an electron emitting material made of an alkaline earth metal oxide such as, and is deposited on the three base metals 2a, 2b, and 2c by a method such as spraying. 3 is a lead wire, which is integrally formed on the insulating substrate 1 by the same method as the base metals 2a, 2b, and 2c. Reference numeral 3a denotes a cathode terminal at the tip of the lead wire, which is connected to the outside via a conductor wire (not shown). Reference numerals 5a, 5b, and 5c are heating elements, and tungsten or the like is formed in a meandering manner by sputtering or the like on one side of the insulating substrate at locations corresponding to the three base metals 2a to 2c. 5d is a heating element 5a to 5c
This is a conducting wire that connects the two in series.

6 is a heater terminal, which is not shown, but is connected to an external conductive wire, and a voltage is applied thereto. 5e is the heating element 5a, 5c on both sides
This is a conducting wire that connects the heater terminal 6 and the heater terminal 6.

Next, the operation will be explained. When a voltage is applied to the heater terminal 6 of the heating elements 5a to 5C, a current flows to the heating elements 5a to 5c, and the gel heat is expressed as the square of the t current and the heating element 5a. It occurs in an amount determined by the product of the electric resistance and the electric resistance of ~5C.

Q-1"XRXt ... (1) However, Q
represents the amount of heat, ■ represents the current, R represents the electrical resistance, and t represents the time.

The above generated heat is transferred to the insulating substrate through thermal conduction and thermal radiation.
The three base metals 2a to 2C are heated through. When the base metals 2a to 2C are heated to an operating temperature of about so o'c, electron beams are emitted from the electron emitting material 4, causing the three-color phosphor screen of the color cathode ray tube to glow.

In the cathode structure configured as described above, each heating element 5
By applying a voltage to a to 5c, each base metal 23 to 2c is
When setting the operating temperature to 00°C, the temperature of the central base metal 2b is the same as the base metal 2a on both sides.

The temperature is higher than 2C. The reason for this is that the heat generating elements 5a and 5c on both sides have heat conduction loss through the heater terminal 6, making it difficult for the temperature to rise, and the central heating element 5b is the same as the heating elements 5a on both sides.

This is because the temperature tends to rise due to heat radiation and conduction from 5c. Therefore, the temperature of the central base metal 2b located in the portion corresponding to the central heating element 5b becomes higher than that of the gaseous metals 2a and 2c on both sides. Generally base metal 2a
The higher the temperature of ~2C is than the predetermined operating temperature, the higher the diffusion evaporation rate of magnesium and silicon, which are reducing elements contained in minute amounts in the base metals 2a to 2c and have the effect of activating the electron emitting material 4. This will accelerate the

As a result, when operating for a long time, the electron emission characteristics from the high-temperature center base metal 2b will change.
, 2c, it starts to deteriorate earlier, and the balance of electron emission characteristics from the three base metals 2a to 2c is lost, resulting in a change in color tone on the phosphor screen, which is called white balance loss.

[Problem to be solved by the invention]

Since the conventional cathode structure is constructed as described above, the temperature of the central base metal 2b is higher than that of the base metals 2a and 2 on both sides.
As a result, the temperature of the central base metal 2
There was a problem in that the electron emission characteristics from b deteriorated early during operation, causing a change in color tone.

This invention was made to solve the above-mentioned problems, and the purpose is to obtain a cathode structure that can substantially equalize the operating temperatures of the three base metals and suppress changes in color tone during operation. shall be.

(Means for Solving the Problems) In the cathode structure according to the present invention, among the three heating elements arranged in a straight line, the resistance value of the conductor connecting the heating elements on both sides and the heater terminal is determined by comparing the resistance value between the heating elements and the heater terminal. The resistance value is greater than the resistance value of the connecting conductor.

[For production]

In this invention, since the resistance value of the conductive wires from the heating elements on both sides to the heater terminal is increased, the resistance value of this ribbon portion becomes high, and therefore the amount of heat generated in this portion increases. Thermal conduction losses can also be reduced, so that the operating temperature of the central base metal can be made approximately the same as the operating temperature of the base metals on both sides.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure shows a plan view of a cathode structure according to the present invention in which a heating element is adhered to a heat-resistant insulating substrate, and each reference numeral is the same as in the conventional case shown in Fig. 4, so the same reference numeral is given. The invention will be omitted. In FIG. 1, three heating elements 5a to 5c made of tungsten thin films, conductive wires 5d and 5e, and a heater terminal 6 are integrally formed by sputtering. The thickness of each thin film is 3 microns. The ribbon width of the heating elements 5a to 5c is 0.2 M, and they are formed in a meandering manner at a pitch of 0.3 m. 3 heating elements 5a
5c are connected in series by a conductor 5d, and the heating elements 5a, 5c on both sides and the heater terminal 6 are connected by a conductor 5e. The ribbon width of the conducting wire 5d is from the heating element 5a to
It is 0.2-, which is the same as the ribbon width of 5c, and the heating element 5 on both sides
The ribbon width of the conducting wire 5e connecting the heater terminal 6 and the heater terminal 6 is 0. It's IM. Although not shown, a nickel wire with a diameter of 0 or 1 m is welded and fixed to the heater terminal 6.
Voltage is applied from outside.

By configuring the cathode structure as described above, when a voltage is applied from the heater terminal 6, each of the heating elements 5a to 5c connected in series generates heat by Joule heat. on the other hand,
The conductive wire 5e connecting the heating elements 5a, 5c on both sides and the heater terminal 6 has a narrow ribbon width and therefore has a high resistance value. Therefore, since the flowing current value is unchanged from the conventional one, the amount of heat generated in this part increases significantly compared to the conventional one. That is, the conducting wire 5e between the heating elements 5a, 5c and the heater terminal 6
generates heat, it is possible to prevent the temperature of the heating elements 5a and 5c from decreasing. Furthermore, since the width of the conducting wire 5e is narrowed, heat conduction loss from the heating elements 5a, 5c to the heater terminal 6 can also be reduced. As a result, the temperatures of the three heating elements 5a to 5c can be made substantially equal.

In this way, it has become possible to make the temperatures of the three heating elements 5a and 5c substantially uniform. Figure 2 shows base metals 2a-2.
As shown in the temperature characteristics of c, there is almost no difference in temperature between the center and both sides of the base metal, as shown by the circle in the figure. Incidentally, regarding the temperature characteristics of the base metal of the conventional cathode structure, as shown by the X mark, the temperature of the central base metal 2b is higher than that of the base metals 2a and 2c on both sides.
The temperature was approximately 30°C higher than that of the previous year.

In the embodiment, a method of increasing the resistance value by narrowing the ribbon width of the conducting wire 5e has been described, but the same effect can be obtained by reducing the ribbon thickness of the conducting wire 5e. In addition to tungsten, the material of the heating element may be a high melting point heat-resistant metal such as molybdenum, titanium, or rhenium.

〔Effect of the invention〕

As explained above, according to the present invention, the resistance value of the conductive wire connecting the heating elements on both sides and the heater terminal is made larger than the resistance value of the conductive wire connecting the heating elements, so that three heating elements connected in series can be connected to each other. As a result, the temperatures of the three base metals are also made uniform, the electron emission characteristics are stabilized over a long period of time, and changes in color tone during operation can be suppressed.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a cathode structure according to an embodiment of the present invention;
FIG. 2 is a graph showing the temperature characteristics of the cathode assembly, FIGS. 3 and 4 are front and back plan views of a conventional cathode assembly, and FIG. 5 is a cross-sectional view. 1... Heat-resistant insulating substrate, 2a to 2c... Base metal,
5a to 5c... heating element, 5d, 5e... conducting wire, 6.
...Heater terminal. Note that the same reference numerals in the figures indicate the same or equivalent parts. Agent Masuo Oiwa 148 = ΦII! 3. Procedural amendment (voluntary) 1. Indication of the case Japanese Patent Application No. 1983-93935 2. Name of the invention Cathode structure 3. Name of the person making the amendment (601) Mitsubishi Electric Corporation Representative Moriya Shiki 4 , Agent 5, Subject of amendment 6, Contents of amendment (1) "There is conduction loss" on page 4, line 6 of the specification is corrected to "conduction loss is large." (2) Delete "Ya heat conduction" on page 4, line 8. that's all

Claims (1)

[Claims] Three base metals arranged linearly on one side of the heat-resistant insulating substrate, an electron emitting material coated on the base metal, and three base metals on the other side of the heat-resistant insulating substrate. In a cathode assembly consisting of a thin film ribbon-shaped heating element formed in a meandering manner on a part facing the heating element, a conductive wire that electrically connects the three heating elements in series, and a heater terminal, at least the heating elements on both sides A cathode assembly characterized in that the resistance value of the conductive wire from the to the heater terminal is greater than the resistance value of the conductive wire connecting the heating elements.