JPS61264648A - Image display device - Google Patents

Abstract

PURPOSE:To prevent shaking of picture and fluctuation of brightness during display of image by extending a line cathode at the extension load region providing in common an extending member and a load member having a friction surface resulting in a frictional force required for showing the anti-vibration effect to the line cathode. CONSTITUTION:When a pulse voltage is applied to a line cathode 11 to emit hot electrons, a current flows for a very short period, the line cathode 11 expands thermally and the natural frequency of line cathode 11 changes. When the natural frequency becomes almost equal to the period of pulse, the line cathode resonates. Friction which is sufficient for resulting in anti-vibration effect is given to the extension load region of line cathode 11 and vibration energy of line cathode 11 can be absorbed by friction by loading between a load case 13 and a spacer 18, and between a load axis 17 and a spacer with a low load spring 20 for spacer and a spring 21 for load axis, and thereby vibration amplitude of line cathode which has been + or -20-200mum can be reduced to + or -20mum or less even in maximum. Accordingly, a high grade picture without shaking and fluctuation of brightness can be obtained.

Description

[Detailed description of the invention] Industrial applications The present invention relates to an image display device using thermionic emission.

Conventional technology Conventionally, cathode ray tubes have been mainly used as display elements for displaying color television images, but conventional cathode ray tubes have a much longer depth than the screen, making it difficult to manufacture thin television receivers. It was impossible to do so.

In addition, although EL display elements, plasma display elements, liquid crystal display elements, etc. have recently been developed as flat display elements, all of them are insufficient in terms of performance such as brightness, contrast, and color reproducibility of color display. , it has not yet been put into practical use. Therefore, we aimed to achieve a device that could display color television images on a flat display device using electron beams, and we divided the screen vertically into multiple equal parts. The electron beam is deflected vertically at every minute to display multiple lines, and is further divided horizontally into multiple lines to display R-G- for each minute.
The phosphors such as B are made to emit light sequentially, and the R-G,
There is a device in which the amount of electron beam irradiation on a phosphor such as B is controlled by a color video signal, and the entire device is used as a television image display device.

An example of the conventional image display device mentioned above will be described below with reference to the drawings. FIG. 8 shows a conventional image display device. In Fig. 8, (1) is the electron beam source and the line cathode, (2) is the support stand that supports and fixes both sides of the line cathode, and (3) is the line cathode (1) that is stretched by applying a load. Leaf spring, (4) is mesh-like control electrode, (5) is phosphor, (6) is the back! The poles (7a) and (7b) are containers.

Three operations of the image display device configured as described above will be described below. First, a line cathode (1) as an electron beam source is attached to a plate spring (2) attached to a support base (2) so as to generate an electron beam distributed linearly in the horizontal direction.
3), and a plurality of such wire cathodes (1) are provided in the vertical direction at appropriate intervals. These green shades i(υ) are composed of oxide cathode material coated on the surface of a tungsten wire of, for example, 10 to 20μ. The back electrode (6) suppresses the generation of electron beams from other line cathodes (1) other than the line cathode (υ) that is controlled to emit an electron beam for a certain period of time.
It also functions to push out the generated electron beam only in the forward direction. This back electrode (6) is connected to the container (7a) (7
b) may be formed by a coating of electrically conductive material deposited on the inside of the rear wall. Moreover, a planar electron beam emitting cathode may be used instead of the back electrode (6) and the line cathode (1). The mesh-like control jR pole (4) has a green shade i(υ
It is a conductor having horizontally long slits (not shown) facing each of the lines, through which the electron beam emitted from the line cathode (1) passes and simultaneously deflects it vertically or horizontally. The phosphor (5) has R for each horizontally divided electron beam.
-G-B eight color phosphors are provided in pairs, and are applied in stripes in the vertical direction. After inserting the above-mentioned components into the divided containers (7aX7b), the containers (7a) and (7b) are sealed with adhesive frits to maintain a vacuum inside.

Problems to be Solved by the Invention However, in the above configuration, the line cathode (1) becomes longer as the size of the phosphor (5) becomes larger, and becomes more likely to vibrate. For example, if the distance between the support parts of the green shade 1 (IJ support base (2)) is 100ff, the diameter will be 20 to 8
The 0 μm wire cathode (1) generates vibrations with an amplitude of approximately ±20 to 100 μm over a long period of time. When the line cathode (υ) oscillates in this way, its relative position with the control electrode (4) changes, causing image fluctuations and uneven brightness, resulting in image defects.

Therefore, the inventors of the present invention first applied for patent application No. 59-18132.
In Publication No. 4, a method was proposed in which the wire cathode (1) is held by an inorganic thin wire to exhibit vibration isolation and damping effects. Because the wire cathode (1) is arranged in a sutured manner, when vibration occurs in one wire cathode (1), the vibration energy propagates through the inorganic thin wire and the wire cathode (1) where the vibration occurs
) is also vibrated.

Furthermore, when exposed to a resonance state for a long time or when external vibrations are applied, the contact state changes, resulting in variations in the vibration damping effect and a lack of long-term stability.

The present invention solves the above-mentioned problems. It eliminates the above-mentioned conventional drawbacks, has a large vibration-proofing effect against resonance and external vibration, provides stable images, and has flat quality and reliability without uneven brightness. This provides a high quality image display device.

Means for Solving the Problems In order to solve the above-mentioned problems, the image display device of the present invention includes a stretching member that applies tension to the wire cathode so as not to cause deflection, and a vibration-proofing member for the wire cathode. The wire cathode is stretched in a tension load section that shares a load member with a friction surface having a frictional force necessary to exhibit the effect.

Operation The present invention converts the vibration energy of the wire cathode into the energy of the friction caused by the friction surface of the load member and the internal friction of each constituent member, and thereby independently performs vibration isolation for each wire cathode. It is possible to provide a large damping effect with good responsiveness when vibration occurs, and as a result, it is possible to prevent image shaking and brightness unevenness when displaying an image.

Embodiment Hereinafter, an image display device according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows an image display device according to an embodiment of the present invention. In Figure 1, the circle is a conductive wire cathode coated with a substance that has thermionic emission function, such as barium oxide, and @ is the support stand that supports and fixes both terminals of this green cathode east.
σ is the load part case that has a friction surface inside to apply a load to the wire cathode (B) and stretch it, and σ arm is the electrode that controls the beam emitted from the wire cathode Oυ to form a predetermined image. , (to) is a phosphor that emits light upon colliding with the beam passing through the control electrode α and displays an image, and Qlj is a back electrode provided to facilitate the generation of thermoelectrons from the line cathode αυ.

The second case shows the structure of the load part case a1 which has a friction surface inside (171 is the load axis to which the linear cathode αυ is connected and moves freely in the line cathode stretching direction, (g) is the load axis αη). A spacer supported by the case 03, α is a stopper fixed to the load axis αη, 4 is a low-load spring for the spacer interposed between the spacer (G) and stopper 4, e is the stopper α and the load part The spring for the load shaft inserted between the case (2) constitutes a part of the damper that has a frictional force.(A) is the fixture for fixing the wire cathode αη, and the wire cathode αυ is attached to the support opening. The load axis qθ in the fixed load case (to) and the fixing bracket (
2) It is also stretched with a tension of about 80 f.

Regarding the image display device configured in this way, the following describes the first
The operation will be explained using FIG. line cathode αυ
When a pulsed voltage is applied to cause thermionic electrons to be emitted, a current flows through the linear cathode αη during the minute time it takes for the thermionic electrons to be emitted. Then, the temperature of the linear cathode αV changes by an amount corresponding to the amount of heat generated by the product of this current, the square of the resistance of the linear cathode α〃, and the minute time, and the linear cathode aυ thermally expands. Also, when the current stops, contraction occurs due to heat release. When the wire cathode (b) expands and contracts, this tension, which is stretched between the support parts of the support base (6) with a tension of about soy, changes, and as a result, the natural frequency of the wire cathode αυ changes. Resonance occurs when this natural frequency becomes approximately equal to the period when a pulsed voltage is applied. In the case of the conventional example shown in Fig. 8, the wire cathode itself has no damping effect, the suspension spring has no damping effect, and since it is in a high vacuum, there is no damping effect due to air, so a large amplitude is generated. In the case of the above configuration shown in Figure 2, the vibration energy of the wire cathode (B) is transferred to the load case (to) and the spacer (to).
The friction between the load shaft movement and the spacer (G), the load part case □□□, the load shaft α force, and the internal friction energy of the material of the spacer (G) are converted into energy, which gives a large damping effect. It will be done.

In this example, the load function section of four green cathodes (13ui w
Let's calculate the damping effect due to (l w G!η). The equation of forced vibration when receiving damping proportional to speed is shown by the following equation.

'i+2ni+ (l16X: f(t)
(1) Where: X: Amplitude of the line cathode αυ n: Load function section 1.13117) (G) 4■ (C) Attenuation constant ω. : Natural frequency f(t) of the line cathode αυ : External force applied to the line cathode (6) The general solution of equation (1) is for the case of ωo>n. However, XSt : The static frequency of the line cathode α Displacement p: Frequency of vibration of line pole (b) -α*2np/(*♂-p!ri
<3).

Next, in forced vibration, if we consider the work done by external force per cycle, we can see that at any given time, fsill
When a force pt acts, the fulcrum becomes x=Asin(pt-
α) It vibrates in the following form. Therefore, in a steady state, the amount of work W done by the external force during one cycle is w=/fsinptdx=πfA sinα (4) On the other hand,
The energy W' consumed in attenuation is W' = / 2n
pAO)S(p ta> dx=2npyrA”
(5) Since the work W done by the external force during one cycle and the energy W' consumed in damping are equal, from equations (4) and (5), πfAsma = 2 n pπA'' Also, from the experimental results, the conventional line The attenuation constant n0 in the case of only the cathode is nQ = 0.01~0.001 (1/5
ec), and the load function section (2) αη(g) of this embodiment
The attenuation constant n1 when using αIGQCQ is n1=1~
0.5 (t/5ec). From this, the amplitude ratio is A. According to this embodiment, the load case By applying a load between spacer 4 and spacer (9) and between load shaft qη and spacer (to) using spacer paper load spring 4 and load shaft spring □□□, A sufficient amount of friction is provided to exhibit the vibration-proofing effect, and the vibration energy of the green cathode circle is absorbed by the friction between the load case (13) and the spacer (to) and between the load shaft αη and the spacer (to). As a result, the amplitude of the conventional line cathode, which was ±20 to 200 μm below resonance, can be reduced to at most ±20 μm.This significantly reduces image shake and brightness unevenness. and the result does not degrade over time, resulting in reliable high-quality images.This effect also acts independently on each line cathode (2).

Effects of the Invention As described above, the present invention generates frictional force by providing a load member having a frictional surface in its structure in the load function section that stretches the wire cathode, so that even when the length of the wire cathode becomes long, Even if external vibration or electric vibration is applied, the damping effect works stably, and the optimum conditions can be selected very easily, so that the wire cathode does not vibrate with a large amplitude. It is possible to obtain high-quality images with no image fluctuation or uneven brightness, and the practical effects thereof are extremely large.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view of an embodiment of an image display device according to the present invention, FIG. 2 is an enlarged view of the main part thereof, and FIG. 8 is a partially cutaway perspective view of a conventional example.

Claims (1)

[Claims] 1. A line cathode that emits thermionic electrons, a control electrode that controls the flow of thermionic electrons emitted from the line cathode, a phosphor capable of emitting light upon receiving the thermionic electrons, and a line cathode that emits the thermionic electrons from the line cathode. An image display device comprising: a back electrode provided to emit light; and a stretching load section that shares the tension member of the linear cathode with a load member having a friction surface that damps vibrations of the linear cathode.