JPS5935498B2 - Electron beam deflection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electron beam deflection device, and more particularly to a traveling wave electrostatic deflection device for an electron beam of a cathode ray tube.

An oscilloscope cathode ray tube (hereinafter simply referred to as "CRTj") that can display electrical phenomena as visible light images.

) Various types of slow wave circuits are known for use in oscillographic devices such as the following.

For example, in the specification of Moulton's invention, US Pat. An electron beam deflection structure is disclosed that travels at substantially the same speed, extends the deflection upper frequency limit, and improves the transient signal response of the device.

The electrostatic deflection (in the vertical direction) of the electron beam in this device is
A deflection signal is applied between conductive plates on either side of the electron beam path to spread the direction of electron flow a significant distance to allow sufficient electron beam deflection.

The length of this deflection plate limits the upper frequency limit that can be applied to the deflection plate for effective deflection of the electron beam.

Since the transient signal voltage contains extremely high frequencies, the length of this deflection plate also limits the response accuracy of the CRT to this transient signal voltage.
As explained in No. 2, conventional circuits of the zigzag type have the undesirable property that it is difficult to synchronize the traveling electric field with the electrons at high operating frequencies.

Thus, in this latter patent, the deflection member is comprised of a mutually parallel zigzag line, a conductive fold connected to successively adjacent strip sections, and a conductive fold connected to each section associated with the zigzag line.
Attempts are made to alleviate the above-mentioned drawbacks by providing a slow wave structure with shielding means to reduce electrical coupling between the IJ tube portions.

Another electron beam deflection device is a delay line type CRT electron beam deflection device as disclosed in US Reissue Patent No. 28223, invented by C.G. Ozonsal.

This deflection device has different widths of deflection. A pair of helical deflection members wound in a rectangular cross-section having a pair of planar side portions separate from the portion.

Two pairs of adjustable ground supplemental spray plates are disposed near opposite planar sides of the helical deflection member to form a delay line of nearly uniform characteristic impedance - however, the conventional deflection described above Since each device is constructed by assembling a large number of parts, it has the disadvantage of being expensive.

According to the present invention, manufacturing costs can be significantly reduced by attaching the zigzag wire directly to the rond, and the drawbacks of conventional deflection devices can be overcome.

The shape of the loop and deflection plate creates a structurally stable configuration.

Basically, the invention is a broadband electron beam deflection device that can be fixed directly to the main support rod (rond) of an electron gun.

To do this, we increased the length of the deflection path and bent the zigzag line loop, which synchronizes the deflection signal and the electron beam, at an angle of about 45 degrees from the deflection plane of the deflection plate, so that the legs at both ends of the loop were attached to the main support rod. Make sure it's almost centered.

The length of the leg between the end of the loop and the glass rond should be as large as possible to limit the capacitance that would reduce the impedance of the deflection plate serving as the transmission line.

In order to keep the average impedance between the input and output ends of the deflection plate constant, the thickness of the loop can be made variable or the dimensions of each deflection section can be made variable.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a high frequency deflection plate with a novel slow wave structure that overcomes the drawbacks of the prior art.

Another object of the present invention is to provide a broadband deflection plate that can be directly fixed to the main support rod of an electron gun.

Still another object of the present invention is to provide a high frequency deflection plate having a slow wave structure that is simple in construction and inexpensive.

The above and other objectives and advantages of the present invention will become apparent upon understanding the following description.

However, the techniques disclosed herein do not limit the technical scope of the present invention in any way, but are merely exemplified so that those skilled in the art can understand the principles and actual application methods of the present invention.
Obviously, various modifications and variations are possible to suit particular applications.

The present invention will be explained below with reference to the drawings.

FIG. 1 shows a slow wave type high frequency deflection structure constructed according to the present invention and used as a conventional vertical deflection device.

As shown, the slow wave deflection structure 10 is housed in an evacuated tube of a CRT.

This tube has a glass neck 12 and a ceramic flap 7.
It includes a flannel portion 14 and a glass face plate portion 16.

These parts are sealed together by a glass-to-ceramic encapsulation of crystalline glass as disclosed in U.S. Pat.

A layer of phosphor 18 forming the CRT's fluorescent screen is applied to the inner surface of a glass faceplate 16 at one end of the bulb.

A cathode 20 that emits electrons is provided at the other end of the tube,
A conventional electron gun 22 is constructed with a control grid, a focus electrode and a heated anode to produce an electron beam 24 .

When a deflection signal is applied to each electron beam 24, the electron beam 24 is deflected vertically by the deflection device 10, and subsequently deflected horizontally by a pair of horizontal deflection plates 26.

After this deflection, the electron beam is accelerated by a high electric field and impinges on the fluorescent screen 18 at high speed.

This latter-stage accelerating electric field is applied to the mesh electrode 28 and the accelerating electrode 30.
formed between.

This acceleration type-30 is a thin electron-transparent aluminum coating applied to the inner surface of the fluorescent screen 18, and is electrically connected to a conductive film 32, made of metal, for example, applied to the inner surface of the ceramic funnel part 14. Ru.

The membrane electrode 32 terminates to the left of the mesh electrode 28 and is electrically connected to an external high voltage DC power source (not shown) via an encapsulated connector pin 34.

The mesh electrode 28 is generally grounded via a support tube 36 whose one end is attached to a mounting ring 38.
A mesh electrode 28 is supported on the tube 8 and its other end is attached to a spring contact 40 which contacts a conductive layer 42 applied to the inner surface of the glass neck of the bulb.

The average output voltage of the horizontal deflection plate 26 is generally applied to the mesh electrode 28, thereby creating a substantially field-free region between the mesh electrode 28 and the output end of the horizontal deflection plate.

Each electrode of the electron gun 22 and the mesh electrode 28 are connected to a base pin 44 that penetrates from the left end of the neck portion 12 of the tube to the outside.
Connected to the outside of the tube via.

However, the deflection members of the deflection device 10 connect to neck pins 46 and 48 that extend outwardly from the sides of the neck portion 12, as described below.

The neck pins 46 and 48 connect to the input and output ends of each deflection member, respectively.

The horizontal deflection plate 26 also connects to a neck pin (not shown) extending outwardly from the tubular neck.

As shown in FIG. 2, a side view of the electron beam deflection device of the present invention, FIG. 3 showing a top view thereof, and FIG. All members 50 are fully supported by four support rods 52, with each deflection member mounted between two glass support rods 52.

Each deflection member 50/I′i has an input end connected to the neck pin 46 via an input lead, and an output end thereof is connected to the neck pin 48 via an output lead (the input/output leads are not shown). ).

As can be seen from these three figures, the output end of the deflection member 50 is expanded, and this expansion is approximately 1/1/2 of the length of the deflection plate.
/Starts from point 3.

Further, the width of the deflecting member increases gradually along the electron beam path, and the width in the direction perpendicular to the electron beam also increases gradually along the electron beam path.

As shown in FIG. 5, each deflection member 50 can be formed from a thin metal plate by pressing or etching in a conventional manner.

In this example, the deflection member is about 0.01 inches (0.01 inches).
25 mi! It is formed from a stainless steel plate with a thickness of J) and a length of approximately 2.85 inches (72 mm).

As shown, a plurality of trapezoidal deflection sections 60 are sequentially coupled to adjacent deflection sections to form a zigzag line between input connector 62 and output connector 64.

Each connector 62, 64 is spot welded to a fine wire drawn out of the tube, of course in a sealed manner, from the tube wall of the tube to form a neck pin 46, 48, respectively, as described above.

Note that the above-mentioned word "trapezoid" means a deflection portion including a trapezoid and a rectangle.

The deflection section 60 has low impedance and is sequentially coupled via loop sections or bifurcated sections 66 alternately arranged on both sides of the deflection section.

When the deflection signal travels from left to right, these bifurcated parts
Form multiple loops that delay the deflection signal.

This, of course, causes the electrons forming the electron beam and the deflection signal to keep pace with each other.

The other end of the bifurcated portion 66 has a width approximately twice that of the branch portion.

The bifurcated portion through which the deflection signal flows is narrow, so the impedance is high.

This increases the overall average impedance and allows it to be driven economically.

That is, in a typical CRT vertical deflection structure, the impedance through which current is supplied from a current source, such as a transistor, determines the deflection voltage.

When the impedance is increased, the same deflection voltage is generated with a small amount of current, so there is no need for expensive transistors that handle large currents.

The wide, unbranched portion of the bifurcated portion 66 (referred to as the "trunk").

) supports the deflection structure. Before continuing with the detailed description of the deflection structure illustrated in FIG. 5, it is important to note the dimensions and manufacturing techniques that have been found to be useful as an embodiment of the present invention, although they are not intended to limit the present invention in any way. I will mention them below.

This structure is assumed to be used for the upper deflection member, but is also the same for the lower deflection member.

In this embodiment, there are twenty-six deflectors 60, and the total length between the input end indicated by dimension line 80 and the output end indicated by dimension line 82 is approximately 2.513 inches (63 mm).

The point at which expansion begins is approximately 0.755 inches (19 mm) to the right of dimension line 80, or at dimension a84, midway between the tenth and eleventh deflection sections.

Between dimension lines 80 and 84, each deflector has a width perpendicular to the beam direction of approximately 0.11 inches (28 mm) and is centered on centerline 86.

The output side position of each deflection section 60 is measured based on the dimension line 80 indicated by X with arrows in both directions, and the pitch of each deflection section 60 is also measured between dimension lines 88 and 90 indicated by arrow Z. It shows.

The position and pinch of each deflector 60 are shown in Table 1 for the illustrated embodiment.

As is clear from the drawings and Table 1, the first ten deflection parts 60 have almost the same dimensions, and the interval is about 0.02.
It is 1 inch (0.5 mm).

By keeping this initial portion constant, a nearly uniform electric field is applied to the electron beam as it passes through it, providing a force on the electron that provides the acceleration needed to deflect the electron beam vertically. , it is possible to prevent the electron beam from becoming out of focus.

Between dimension lines 82 and 84, the width of the deflection section perpendicular to the electron beam increases by an angle 2α.

This α is approximately 2.29° when measured with respect to the dimension line 86.
It is.

In order to make the electric field in the diametrical direction of the electron beam almost uniform at the positions where the upper and lower deflection members are separated from each other, the dimension line 8
The width perpendicular to the electron beam between 2 and 84 must vary.

In addition, between these dimension lines, the width of each deflection section in the direction parallel to the electron beam is changed along with the above-mentioned width in the direction perpendicular to the electron beam, and the overall dimension of each deflection section is the distance between each deflection section. to compensate for the increase in line so that the average impedance of the line is the same as the unextended portion between dimension lines 80 and 84.

Alternatively, the deflection portions may have the same dimensions and the thickness of the zigzag loop may vary depending on VC.

The dimension lines 82 and 84 also cause the trunk of the bifurcated portion 66 to converge at an angle β of preferably about 1.31'.

Additionally, between lines 82 and 84, the stem and zigzag loop of bifurcated portion 66 is tilted forward by an angle ψ of approximately 0.91'.

The deflection structure is removed from the thin metal sheet, bent along line 84 by an amount determined by the maximum amount of deflection required for the CRT, further bent at an angle of about 45° between lines 80 and 84 along broken line 81, and Similarly, it is bent along the broken line 89 at an angle of about 45°.

When this high impedance portion is bent away from the plane of the low impedance portion, the impedance increases further.

In the illustrated embodiment, dashed line 87 is about 0.060 from line 86.
inches (1.5 mm), while dashed line 89 is at an angle θ of approximately 3.201° with respect to line 86.

Following this bending, the trunk of the bifurcated portion 66 is fixed by a conventional method of directly inserting it into a glass support rod that simultaneously supports the other electrode portions of the electron gun of the CRT.

This technique results in lower manufacturing costs and a more robust and simple construction.

By tilting the trunk of the bifurcated section between lines 82 and 84 forward an angle ψ, this section is perpendicular to the axis of the CRT and does not impose a bending moment on the support bar.

Furthermore, if the loop length decreases toward the output end of the deflection device, some simultaneous loss will occur in the electron beam and the deflection signal, but this will have little effect on the display on the CRT screen; All executives need to be near the center of the glass rod.

Although only one preferred embodiment of the present invention has been described above, it will be obvious to those skilled in the art that various changes and modifications can be made without departing from the gist of the present invention.

As is clear from the above description, the electron beam deflection device of the present invention bends the loop parts connected to both sides of the deflection part divided into a plurality of parts to the opposite side of the electron beam, that is, in the direction away from the electron beam, and By attaching the loop portion to the insulating support member, the characteristic impedance of the deflection member can be increased to efficiently generate a deflection voltage, and the deflection member can be easily and securely attached.

[Brief explanation of drawings]

Figure 1 shows a CRT using the electron beam deflection device of the present invention.
FIGS. 2 to 4 are an enlarged side view, top view, and end view (along line 2-2 in FIG. 2) of the electron beam deflection device of the CRT shown in FIG. 1, and FIG. 3 is a plan view of a thin metal plate used for one of the deflection members shown in FIGS. 1 to 3. FIG. In the figure, 10 is an electron beam deflection device, 50 is a deflection member, and 52
is an insulating support member, 60 is a deflection part, and 66 is a bifurcated (loop)
Show part.

Claims (1)

[Claims] 1 At least one of the two deflection members disposed inside the cathode ray tube is connected to a plurality of deflection sections arranged along the tube axis of the cathode ray tube, and these deflection sections alternately formed on both sides of these deflection sections and in contact with each other. In the electron beam deflection device, the loop portion is bent in a direction away from the electron beam, and each of the loop portions is bent in a direction away from the electron beam. An electron beam deflection device, characterized in that an electron beam deflector is attached to an insulating support member.