JPH0251828A - Cathode supporting body structure for cathode-ray tube - Google Patents

Abstract

PURPOSE:To obtain a cathode supporting body structure for a cathode-ray tube with no color tone change and high reliability over a long period by forming the upper end of a center shield tube eyelet lower than the upper ends of shield tube eyelets on both sides. CONSTITUTION:The upper end of a center shield tube eyelet 4B is formed lower than the upper ends of shield tube eyelets 4A and 4C on both sides. The portion of a cathode 1B covered by a center shield tube eyelet 4B is smaller than the portions of cathodes 1A and 1C covered by shield tube eyelets 4A and 4C on both sides by l1-l2, thus heat dissipation for the center cathode 1B is easier than for the cathodes 1A and 1C on both sides, the temperature of the center cathode 1B can be lowered nearly to the same temperature as the cathodes 1A and 1C on both sides. The temperature of three cathodes can be made nearly the same temperature, thereby the evaporation speed of the reducing agent of an electron emitting member is unified, the color tone change such as white balance collapse is prevented over a long period, reliability is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The invention relates to a cathode support structure for a cathode ray tube having three cathodes arranged in-line.

[Conventional technology]

A conventional cathode support structure has a structure as shown in FIG. That is, three cathodes IA, tB, arranged in-line.
Electron emitting members 2A, 2B, and 2C made of a reducing agent and an alkaline earth oxide are fixed to the top pot of tC. The lower end sides of cathodes IA, IB, and IC are supported by support members 3A, 3E3, and 3.
The shield tube eyelets 4A, 4B, and 14Cl are fixed via C.

The shield tube eyelets 4A, 413, and 4C are embedded in the hermetic glass 6 fixed to the support 5. A portion (not shown) of the support 5 is fixed to a support 7I, and this support 7 is supported and fixed to a glass rod (not shown) that supports each electrode (not shown). Further, the cathode IA
, IB, and tC are inserted with heaters 8A, 8B, and 8C, and the heaters 8A, 8B, and 8C are fixed to a heater support (not shown).

Therefore, the electron emitting members 2A, 2B, and 2C are heated by the heaters 8A, 8B, and 8Ct, and the electron emitting members 2A, 2B, and 2C are heated.
A reaction between the 2B and 2C reducing agents and the alkaline earth oxide occurs, and electron emission occurs at an operating temperature of 700-800°C. In this case, the operating temperature is the shield tube eyelet) 4
Maintained by A, 4B, and 4C.

In addition, related to this type of cathode support structure are:
For example, JP-A-53-6564, JP-A-54-1601
No. 60 etc. are mentioned.

[Problem to be solved by the invention]

The above prior art has three shielding cylinder eyelets) 4A.

Since the lengths of 4B and 4C are the same, the temperature of the central cathode IB is about 10° C. higher than that of the cathodes IA on both sides, heat radiation, heat conduction, etc. of the IC.

For this reason, the evaporation rate of the reducing agent in the central electron-emitting member 2B is accelerated, and the electron-emitting characteristics of the central cathode IB begin to deteriorate earlier than those of the cathodes IA and IC on both sides. During long-term use, there was a problem that color tone changes such as white balance collapse occurred.

The object of the present invention is to provide a highly reliable cathode support structure for a cathode ray tube that does not cause color change over a long period of time.

[Means for Solving the Problems] The above object is achieved by forming the upper end of the central shielding cylinder eyelet lower than the upper ends of the shielding cylinder eyelets on both sides.

[Effect]

Since the cathode part covered by the shielding tube eyelet is less in the center than on both sides, the center cathode can dissipate heat more easily than the other cathodes, and the center cathode can be lowered in temperature to almost the same temperature as the cathodes on both sides. It can be rubbed. As a result, the evaporation rate of the reducing agent in the three electron-emitting members becomes uniform, so that color tone changes such as white balance collapse do not occur over a long period of time 1'b'1i.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. In addition, the same or equivalent parts as in FIG. 2 are given the same reference numerals.
The explanation will be omitted. The upper end of the central shielding cylinder eyelet 4B is formed lower than the upper ends of the shielding cylinder eyelets 4A and 4C on both sides. That is, the length from the electron emitting member 2B to the upper end of the shielding eyelet 4B! , is electron emitting member 2
Length l from A, 2C to the top of shielding tube 4A, 4C.

formed longer.

In this way, the portion of the cathode IBi covered by the center shielding tube eyelet 4B is covered by the shielding tube eyelets 4A, 4C on both sides.
From the cathode IA and IC portion covered with 13. -11
．． Since the central cathode IB is smaller than the cathodes IA on both sides,
It is easier to dissipate heat than IC, reducing the temperature of the central cathode IB and the cathodes IA on both sides.

It can be rubbed at approximately the same temperature as IC.

〔Effect of the invention〕

According to the present invention, the temperatures of the three cathodes are kept at approximately the same temperature l.
Since it can be rubbed, the evaporation rate of the reducing agent in the electron-emitting member becomes uniform, and color tone changes such as white balance collapse do not occur over a long period of time, improving reliability.

[Brief explanation of the drawing]

@ Figure 1 is a sectional view showing one embodiment of the present invention, and Figure 2 is a sectional view of a conventional example. IA, IB, tC...Cathode, 2A, 2B, 2C.
...Electron emission member, 4A>4B, 4C...Shielding cylinder eyelet. Figure 1 AνlB, +c: nb 2A, 2B, 2C: Denjin Seihanbu'$A4C, 4C
, 4C: Shielding simple eye left

Claims (1)

[Claims] 1. In a cathode support structure for a cathode ray tube, which is equipped with three cathodes arranged in-line and having an electron-emitting member fixed to the top, and shielding cylinder eyelets arranged on the outside of these cathodes, the central shielding cylinder A cathode support structure for a cathode ray tube, characterized in that the upper end of the eyelet is formed lower than the upper ends of the shield tube eyelets on both sides.