JPS6171537A - Flat type cathode-ray tube - Google Patents

Abstract

PURPOSE:To make the incident angle of an electron beam in the entire area constant and to make the shape flatter by flatter by forming the shape of a fluorescent screen by means of a group of logarithmic spiral curves which are obtained by rotating a plurality of logarithmic spiral curves. CONSTITUTION:An electron gun 3 is housed into the neck portion 2 of a flat glass tube body 1, and a fluorescent screen 5 is slantingly provided against the central axis of an electron beam 7, and thus a flat type cathode-ray tube is formed. Further, using the deflection center of the beam as an origin, an x axis and a y axis are provided through the origin, a logarithmic spiral curve which passes through one point on the x axis at a distance ai from the origin and exists in a x-y plane is set to have an equation r=aie<ktheta>, and ai is assumed as a plurality of logarithmic spiral curves which have a parameter of ai+1>ai (i=0, 1,...), and a curve which is formed by rotating the logarithmic spiral curves about the y axis is set to the shape of the fluorescent screen 5. Accordingly, it is possible to obtain a picture with uniform resolution and to make the shape flatter.

Description

[Detailed description of the invention] C) Industrial use minute hand The present invention relates to a flat cathode ray tube.

- Prior Art Generally, cathode ray tubes used in television receivers and the like have an electron gun placed on an axis perpendicular to the fluorescent surface.

An electron beam is irradiated onto the fluorescent surface through a metal bag film and scanned.

As a result, the cathode ray tube has a larger head and a longer depth, which means that the receiver itself, which is approximately determined by the capacity of the cathode ray tube's fluorescent surface area and its depth, has become larger, making it possible to create a smaller and thinner television receiver. This is a major problem when configuring.

For this reason, the cathode ray is a flat cathode ray that has a fluorescent surface tilted with respect to the central axis of the electron beam, and there is almost no difference in spot diameter due to differences in beam travel distance, and almost no change in resolution due to differences in travel distance. A tube has been devised, but in such a tube, the angle of incidence of the beam on the phosphor surface has a large effect on the resolution.

One way to solve this problem was proposed by the applicant in the patent application filed in 1983.
This is proposed in No. 125101, and will be explained below with reference to FIGS. 5 to 7.

FIG. 5 shows a schematic configuration of a flat cathode ray tube, with main parts cut in section, and (1) is a flat glass tube body;
An electron gun (3) is enclosed inside the neck portion (2) of 11, and a deflection coil (4) is attached to the outside. In this flat cathode ray tube, the fluorescent surface (5) is inclined with respect to the central axis (7) of the beam [the traveling direction of the electron beam (6) in the non-deflected state] and is located on the inner surface of the first panel (8). The central axis (7) is set to be different from approximately the center of the fluorescent surface (5). Then, the electron beam (6) emitted from the electron gun (3) is horizontally and vertically deflected by a deflection coil (4), and the fluorescent surface (5)
Since all the lights are stimulated to emit light, the emitted fluorescent surface (
5), the observer looks at the second panel (9) from the electron beam incident side.
) can be observed through the observation window.

By the way, the electron beam (6) directed against the fluorescent surface (5)
The fluorescent surface (5) is formed by the following method in order to make the incident angle of light equal over the entire area of the fluorescent surface.

That is, in the sixth factor, (4) is the deflection center, and the deflection center (4) is taken as the origin of this coordinate, and the bridge coordinate system will be considered below. The curve l is a logarithmic spikele curve, and the general expression of this curve is Ky=a e k′l (a: constant, k=□e:
(base of natural logarithms).

tande 1 (PI) (Pl) is a point on the logarithmic spikele curve ■, and one curve line segment PI, P2 is the side opposite to the electron beam in the cross section of the fluorescent surface (5) (the incident side of the electron beam). ), and for convenience of explanation, the X-axis is the electron beam (
6) is aligned with the central axis (7).

(TI) (T2) are the respective points (Pl) (Pl
) is the tangent to the logarithmic spikele curve at ). (T1
)(T2)(911, ψ2≦π/2) are API
The angle formed by (=γ1) and (T1).

It is the angle formed by 7-cho2 (=γ2) and (T2). In other words, these (T1) and (T2) are the incident angles of the electron beam with respect to the cross section of the fluorescent surface at (PI) and (Pl).

By the way, the logarithmic spikele curve [F] is a curve in which the angle between the straight line connecting any point on the curve and the origin (8) and the tangent at that point is constant.

Therefore, if the curved line segment PIF2ft is set as the curved shape on the side facing the electron beam in the cross section of the fluorescent surface (7),
Not only are the incident angles at both ends of the fluorescent surface equal (ψ1 = 92), but also the incident angle of the electron beam from the center of deflection onto one curved segment PIP2 is constant at every point on the curved segment PIF2. becomes.

Then, the surface is completed as a fluorescent surface (as shown in Figure 7, the curved line segment p + p 2t-y!Il] rotates around the center of the curved line segment p + p 2t-y!Il) and is formed as the trajectory of the curved surface CF3)'
It has a fluorescent surface. Therefore, the angle of incidence from the center of deflection (4) to every point on the curved surface (3) is completely constant.

The angle of incidence of the electron beam on the phosphor surface formed in such a shape can be made completely constant at every point on the phosphor surface.

By the way, in a flat cathode ray tube, the closer the fluorescent surface is to a flat surface, the thinner the tube is, which is also advantageous when processing a curved panel or when coating a phosphor or the like.

However, the conventional method for forming a fluorescent surface simply rotates one logarithmic spiral curve, so the curve 1'c) at the center and the curve 1'R) at both ends of one curved surface (J
There is a difference in the thickness direction of the phosphor surface due to the rotation, which has been an obstacle to realizing a flat cathode ray tube. Note that Japanese Patent Publication No. 42-7491 also describes a flat cathode ray tube in which a fluorescent surface is formed by a similar method.

(c) Problems to be Solved by the Invention The present invention is a flat cathode ray in which the angle of incidence of the electron beam on the phosphor surface is constant at all points, and the shape of the phosphor surface can be made as flat as possible. The purpose is to provide pipes.

(b) Means for solving the problem In the flat cathode ray tube of the present invention, the deflection center of the electron beam is taken as the origin, the central axis of the electron beam passing through this origin is the X axis, and the origin is perpendicular to this X axis. Fireflies are generated by a group of logarithmic spikele curves obtained by rotating a plurality of logarithmic spikele curves with a constant incident angle that exist in the X-7 plane at the same origin by a predetermined angle around the y-axis, with the passing axis being the y-axis. The shape of the light surface is formed.

(e) Effect By configuring as described above, the shape of the fluorescent surface becomes as close to a flat surface as possible.

(F) Example 1 Embodiment f of the present invention: This will be explained with reference to Figures 1 to 4, but the structure of the flat glass tube except for the shape of the fluorescent surface is the same as that in Figure 'IJIIS. Therefore, the explanation will be omitted.

In Fig. 2, (4) is the origin corresponding to the center of deflection in a flat cathode ray tube. The axis in the vertical deflection direction that is perpendicular to the X-axis and passes through the origin CAJ is defined as the y-axis.

The curve (/?O) has the deflection center as the origin body, and a point (X, γ
) = (ao, O) and is a logarithmic spikele curve that exists in this x-y plane, and this curve (7o) is θ =: a oe where r: the origin (5) and the curve (lO ) is the distance of a straight line connecting any point on the curve (lO), to = - (ψ is the origin tanψ) and the straight line connecting any point on the curve (lO).

It is expressed as the angle formed by the tangent line at one point on this curve (lO).

In addition, in Figure 2, the intersection of the X axis and the logarithmic spikele curve is the reference (θ = 0), and the increase and decrease of θ is set in the direction of the arrow in Figure 1. If an arbitrary point is CP+)(P2), then (T')('r2
) is each point CP mentioned above? )(P2). Also, (Pl) (ψ2) [ψ1゜ψ2≦/2] are the angles formed by API and (T1), and the angles formed by rT1 and (T2), respectively, and if the head is replaced, these (Pl) (ψ2) is (P
l ) is the angle of incidence of the electron beam on the fluorescent surface at (P2), and has the relationship ψ1=92.

In this way, a logarithmic spiral curve is a curve in which the angle between the straight line connecting any point on the curve □□□ and the origin (8) and the crossing line at that point is constant; If the cross section of the fluorescent surface is curved on the electron beam incident side, the incident angle of the electron beam with respect to the fluorescent surface will be constant at all points.

By the way, under the condition that the incident angle ψ is constant (that is, k is constant), there are an infinite number of logarithmic spikele curves that exist in the xy plane with the deflection center as the origin.

In other words, if the formula expressing the logarithmic spikele curve is = a10 and θ, ki is constant and the distance a1't is the parameter, and this ai is varied, an infinite number of logarithmic spikele curves can be drawn in the same plane (x-y plane). This is the translation. In FIG. 2, the logarithmic spike passing through the points aO, at, and a2 on the X axis has θ kθ and r nil curve T =! L8 e, rr =: a, ea
2ekB is shown as a representative.

In the present invention, a fluorescent surface is formed by utilizing a plurality of logarithmic spikele curves existing in the x-y plane, and the method for forming the same will be explained below.

That is, in Figure 2! -7 logarithmic spikele curve r = = a (18 with θ and the coefficient of this curve I!LO
A plurality of larger logarithmic spiral curves r; to θ a 16 . 7:: Set θ,...tg to IL2θ. And the standard logarithmic spikele curve η″=&Oek
θ! A plurality of logarithmic spikele curves fixed on the −7 plane and determined as described above are rotated around y4ii+ at a larger rotation angle as the coefficient a1 becomes larger. That is, for coefficients a 2 > a + > 0, l'421 > l+h + I >
Rotate with the relationship 1・α01 (=0).

FIG. 1 is a diagram showing such rotation.

It can be seen that the curved surface shape formed by the group of logarithmic spikele curves arranged by this rotation is flattened compared to the conventional one simply rotated around the y-axis.

By the way, as shown in FIG. 7 of the conventional example, when a curved surface formed simply by rotating a single logarithmic spikele curve around the y-axis is used as a fluorescent surface shape, it is formed by scanning an electron beam. The raster is fan-shaped as shown in Figure 3, and in order to correct this fan-shaped raster to a rectangular raster, the sawtooth wave current for vertical deflection, the horizontal deflection, and the sawtooth wave current must be corrected by a correction circuit for deflection driving. If a flat cathode ray tube, which is characterized by high power consumption, is incorporated into a small, thin, pocketable television, what will happen to the television circuit? A battery is used as a driving power source, but it goes without saying that increased power consumption is disadvantageous in realizing such a small 1G type child television image reception.

Therefore, in the present invention, power consumption can be reduced by a method as described below.

A curved surface formed by a group of logarithmic spikele curves obtained by rotating around one axis with the relationship &a is defined as the shape of the fluorescent surface on the electron beam incident side. The point θ=0 of each logarithmic spikele curve obtained by this rotation is VCH on the When a curved surface is used as a fluorescent surface, a raster formed by an electron beam yields a trapezoidal raster with corrected raster distortion in the vertical deflection direction, as shown in FIG.

In this way, the raster distortion in the vertical deflection direction is corrected by the shape of the phosphor surface without relying on the correction circuit, so only the raster distortion in the horizontal deflection direction needs to be corrected by the correction circuit. This means that it is possible to reduce power consumption and the number of parts when configuring the machine.

In addition, in the rotation shown in Fig. 1, a fluorescent surface is formed only on one side of the A fluorescent surface may be formed by a plurality of logarithmic spikele curves obtained by rotating at equal angles (±α).

(G) Effects of the Invention According to the present invention, the angle of incidence of the electron beam on the gold region of the fluorescent surface is constant, and an image with uniform resolution can be obtained.
Since the shape of the phosphor surface can be made closer to a flat surface, flattening of the cathode ray tube body is promoted and manufacturing thereof is facilitated, which is particularly useful.

[Brief explanation of drawings]

Figure 1g1 is a diagram for explaining the method of forming the fluorescent surface used in the present invention, Figure 2 is a diagram showing the curve used therein, and Figure v15 is a diagram showing the raster shape formed by the conventional method. , @4 is a diagram showing a raster shape formed by the present invention, '@5 is a cross-sectional view of a flat cathode ray tube, nest 6 is a diagram for explaining a logarithmic spiral curve, and FIG. 7 is a diagram showing a conventional raster shape. FIG. 3 is a diagram for explaining a method of forming a fluorescent surface. (1)... Flat glass tube body, (5)... Fluorescent surface, (
7)... Central axis of electron beam, (A)... Deflection center (origin), (JO)(r+)i'2)... Logarithmic spikele curve.

Claims (2)

[Claims] (1) A flat cathode ray tube whose fluorescent surface is inclined with respect to the central axis of the electron beam, with the deflection center of the electron beam as the origin, and the central axis passing through the origin as the x-axis.
The y axis is an axis that is perpendicular to the axis and passes through the origin, passing through the origin and a point on the x axis that is a distance a1 from the origin,
A logarithmic spiral curve existing in the x-y plane is expressed as γ=a_
When is^k^θ (k=1/(tanφ), φ is constant at the incident angle), the distance a_i is a_i+1>a_i
Assuming a plurality of logarithmic spiral curves with parameters such as (i = 0, 1, 2, ...), each curve is rotated around the y-axis at an angle α_i (however, α_i_+_1>
1. A flat cathode ray tube characterized in that a curved surface formed by rotating the tube by α_i, α_i=0) forms a fluorescent surface on the electron beam incident side. (2) The plurality of logarithmic spiral curves are a_i=1/
The flat cathode ray tube according to claim 1, wherein the flat cathode ray tube is rotated according to the relationship (cos α_i)·a_0.