JPS618833A - Beam focusing device - Google Patents
Beam focusing deviceInfo
- Publication number
- JPS618833A JPS618833A JP13035384A JP13035384A JPS618833A JP S618833 A JPS618833 A JP S618833A JP 13035384 A JP13035384 A JP 13035384A JP 13035384 A JP13035384 A JP 13035384A JP S618833 A JPS618833 A JP S618833A
- Authority
- JP
- Japan
- Prior art keywords
- magnetic field
- spot
- focusing lens
- deflection
- flux density
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
- H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
- H01J29/56—Arrangements for controlling cross-section of ray or beam; Arrangements for correcting aberration of beam, e.g. due to lenses
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
本発明は陰極線管のビーム集束装置に関するものである
。DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a beam focusing device for a cathode ray tube.
従来例の構成とその問題点
近年、陰極線管（以下ＣＲＴと略す）を用いた大型ディ
スプレイが実用化されてはいるが、高輝度化のために、
ビーム電流を更に増加する傾向にある。特に投写型ディ
スプレイの様に螢光体を高電流密度で動作させているも
のは、集束特性の性能が画質を左右している。更にキャ
ラクタディスプレイや高品位テレビディスプレイ等の高
精細度な用途については、画面周辺の集束特性が最も重
要になって来ている。Conventional configuration and its problems In recent years, large displays using cathode ray tubes (hereinafter abbreviated as CRT) have been put into practical use, but in order to achieve high brightness,
There is a trend to further increase the beam current. Particularly in projection displays where the phosphor is operated at a high current density, the performance of the focusing characteristics influences the image quality. Furthermore, for high-definition applications such as character displays and high-definition television displays, the focusing characteristics around the screen are becoming most important.
以下に従来のビーム集束装置について説明する。A conventional beam focusing device will be explained below.
第１図は従来のビーム集束装置の構成図を示すものであ
り、１は電子ビームが放出される電子銃である。２は集
束レンズであり、放出された電子ビームをターゲット面
３に集束させるものである。FIG. 1 shows a configuration diagram of a conventional beam focusing device, where 1 is an electron gun from which an electron beam is emitted. A focusing lens 2 focuses the emitted electron beam onto the target surface 3.
４は電子ビームをターゲット面３に偏向走査させる偏向
手段であり、一般的には偏向走査させる偏向手段であり
、一般的には偏向ヨークが用いられる。Reference numeral 4 denotes a deflection means for deflecting and scanning the electron beam on the target surface 3, which is generally a deflection means for deflecting and scanning, and generally a deflection yoke is used.
以上のように構成された従来のビーム集束装置について
、以下その動作について説明する。電子銃１から出た電
子ビームは、集束レンズ２によって集束されるが、一般
的には、静電集束レンズが用いられるが、高精細度ＣＲ
Ｔでは、電磁集束コイルを用いた磁界レンズの場合が多
い。偏向手段４は、受像管では、前述した様に電磁偏向
方式が用いられており、螢光体を塗布されたターゲット
面を水平走査と垂直走査によりラスタを形成する。The operation of the conventional beam focusing device configured as described above will be described below. The electron beam emitted from the electron gun 1 is focused by a focusing lens 2. Generally, an electrostatic focusing lens is used, but a high-definition CR
In T, a magnetic field lens using an electromagnetic focusing coil is often used. In the picture tube, the deflection means 4 uses an electromagnetic deflection method as described above, and forms a raster by horizontally scanning and vertically scanning a target surface coated with a phosphor.
しかしながら上記の様な構成では、偏向コイルの磁界分
布の均一性の問題から偏向走査を加えた画面の周辺では
、ビームスポット形状が、中央に対し、スポット径が大
きくなると共に、第５図に示す様に、斜め方向に歪んだ
スポットになる事が多い。特に、偏向電力の省力化とい
う点からＣＲＴのネック径、および偏向ヨークは出来る
だけ細い径寸法を採用したいので周辺の歪は増加する問
題点を有していた。画像や動画表示の場合は、周辺画質
は、少し劣化しても問題は無いが、コンビュ？
＝夕やグラフィク情報の様な場合は、むしろ反
対に周辺の画質の方が重要になってくる。したがって、
周辺文字の解読限界がビーム電流の上限を決めてしまう
事になり、輝度を画像の時と同レベルまで上昇させる事
が不可能になる。However, with the above configuration, due to problems with the uniformity of the magnetic field distribution of the deflection coil, at the periphery of the screen where deflection scanning is applied, the beam spot shape becomes larger than the center, and the spot diameter becomes larger as shown in Figure 5. This often results in spots that are distorted diagonally. In particular, from the viewpoint of saving deflection power, it is desirable to make the neck diameter of the CRT and the deflection yoke as small as possible, which has the problem of increasing peripheral distortion. When displaying images and videos, there is no problem even if the peripheral image quality deteriorates a little, but the combination?
= In cases such as sunset or graphic information, on the contrary, the image quality of the surrounding areas becomes more important. therefore,
The limit of deciphering peripheral characters will determine the upper limit of the beam current, making it impossible to raise the brightness to the same level as when shooting images.
発明の目的
本発明は上記従来の問題点を解消するもので、偏向感度
を下げる事なく集束レンズの手前に、ビームスポット形
状を補正する手段を設け、コーナースポットのスポット
径を小さくし、解読限界を上昇させることが出来るビー
ム集束装置を提供す不事を目的とする。Purpose of the Invention The present invention solves the above-mentioned conventional problems.It is an object of the present invention to provide means for correcting the shape of the beam spot in front of the focusing lens without lowering the deflection sensitivity, thereby reducing the spot diameter of the corner spot and reducing the decoding limit. The purpose of the present invention is to provide a beam focusing device capable of elevating the beam.
発明の構成
本発明は、集束レンズ系２と偏向手段４と、磁界発生装
置６とを備えたビーム集束装置であり、磁界発生装置に
、画面周辺に対応する変調電流を流し、ビームスポット
形状をダイナミック的に制御し、ビーム電流を増加して
も１周辺画質が劣化しない様にできるものである。Structure of the Invention The present invention is a beam focusing device that includes a focusing lens system 2, deflection means 4, and a magnetic field generator 6. A modulation current corresponding to the periphery of the screen is passed through the magnetic field generator to shape the beam spot. It is possible to dynamically control the beam current so that the image quality of one periphery does not deteriorate even if the beam current is increased.
実施例の説明
第２図は、本発明の実施例における構成図を示
グすものである。第１図と同様の役目をするものは
同一符号とする。第２図の５は磁界発生装置であり、ビ
ームスポットを制御するものであり、具体的−例として
第３図にその構造を示す。DESCRIPTION OF EMBODIMENTS FIG. 2 shows a configuration diagram of an embodiment of the present invention.
It is a good thing. Components having the same role as in FIG. 1 are given the same reference numerals. Reference numeral 5 in FIG. 2 is a magnetic field generating device which controls the beam spot, the structure of which is shown in FIG. 3 as a specific example.
以上の様に構成されたこの実施例のビーム集束装置につ
いて以下その動作を説明する。The operation of the beam focusing device of this embodiment constructed as described above will be explained below.
第１図の電子ビーム軌道かられかる様に、偏向手段４の
位置では、ビームは完全に集束していなくである大きさ
に分布している。従って偏向磁界に均一性が管軸まわり
にせまいため、偏向されたビームスポットは歪んでしま
う。そこで本発明は第２図の５に示した様に、集束レン
ズ２に入射する前の場所で、偏向歪に生ずる反対の歪補
正をあらかじめ与えるものであり、第３図に示した４極
磁界発生装置で、ビームスポットにカを印加するもので
ある。ビーム軸を２軸とし、水平をＸ軸。As can be seen from the electron beam trajectory in FIG. 1, at the position of the deflection means 4, the beam is not completely focused but is distributed in a certain size. Therefore, since the deflection magnetic field is not uniform around the tube axis, the deflected beam spot is distorted. Therefore, in the present invention, as shown in 5 in FIG. 2, the opposite distortion correction that occurs in the deflection distortion is given in advance at a location before the beam enters the focusing lens 2, and the quadrupole magnetic field shown in FIG. This is a generator that applies force to the beam spot. The beam axis is the two axes, and the horizontal is the X axis.
垂直をｙ軸とすれば、磁極の方向は、ｘ、ｙに配置すれ
ば、ｘ′、ｙ′軸の角度の方向に磁束Ｂが発生する。し
かも磁束Ｂは、ｚ軸上では、打ち消し合って零になる。If the vertical direction is the y-axis, and the magnetic poles are arranged in the x and y directions, magnetic flux B is generated in the angular direction of the x' and y' axes. Moreover, the magnetic fluxes B cancel each other out and become zero on the z-axis.
しかも、中央を対称にして磁束Ｂの向きが逆転するため
、ビームスポットに加わる力はＦの矢印で示したベクト
ル方向になり、ビーム形状は、斜め方向に制御できる。Moreover, since the direction of the magnetic flux B is reversed with the center being symmetrical, the force applied to the beam spot is in the vector direction shown by the arrow F, and the beam shape can be controlled in an oblique direction.
第４図は、磁束Ｂを、Ｘ軸にそって表示しだものであり
、４極磁界の制御電流１１． Ｉ２をそれぞれ逆にする
と、力Ｆは逆向きになる。従って第５図に示した様にコ
ーナ一部の歪を補正するためにはＩ１ の電流は、第
６図に示す様に、水平周期の波形を垂直周期で平衡変調
した波形を加えれば良い事がわかる。即ち、画面中央は
、磁界発生装置５によっては何ら変調される事なく、周
辺のみを補正する事が出来る。FIG. 4 shows the magnetic flux B along the X-axis, and shows the control current 11 of the quadrupole magnetic field. If I2 is reversed, the force F will be in the opposite direction. Therefore, in order to correct the distortion in a part of the corner as shown in Fig. 5, it is sufficient to add a waveform that is a balanced modulation of the horizontal period waveform with the vertical period to the current of I1, as shown in Fig. 6. I understand. That is, the center of the screen is not modulated in any way by the magnetic field generator 5, and only the periphery can be corrected.
以上の様にこの実施例傾よれば、磁界発生装置６を集束
レンズ系２の手前に配置し、がっ、時間的に変調する事
により周辺スポットを改善する事が出来る。所謂アステ
ィグマス補正を、ダイナミック的に補正出来るものであ
り、ダイナミックフォーカス補正後、偏向収差が原因で
残留するビームスポットの、収差が改善される。As described above, according to this embodiment, the magnetic field generating device 6 is placed in front of the focusing lens system 2, and the peripheral spot can be improved by temporally modulating the magnetic field generating device 6. The so-called astigmatism correction can be dynamically corrected, and the aberration of the beam spot that remains due to the deflection aberration after the dynamic focus correction is improved.
磁界発生装置４は、実施例に於いては、集束レンズ系の
手前に設けた方法で説明したが、偏向手段の手前であれ
ば、同様の動作が可能であるので集束レンズ系の後方に
配置してもよい。一般的には偏向手段は偏向コイルが多
いので、集束レンズ系の前方手前の方が配置し易い。In the embodiment, the magnetic field generator 4 has been described as being provided in front of the focusing lens system, but the same operation is possible if it is in front of the deflection means, so it may be placed behind the focusing lens system. You may. Generally, the deflection means is often a deflection coil, so it is easier to arrange it in front of the focusing lens system.
前述した様に集束レンズ系は静電方式でも電磁方式でも
本発明の動作には影響がない。偏向手段も、水平・垂直
走査方式をとるものであれば、コーナーの偏向収差は同
様に発生するもので、電磁偏向でも静電偏向方式でも可
能である。特に磁界発生装置は、交流磁界が発生するの
で、集束レンズの後方に配置する場合は、静電偏向方式
の方が磁界結合を少なく出来ることは言うまでもない。As mentioned above, whether the focusing lens system is an electrostatic type or an electromagnetic type has no effect on the operation of the present invention. As long as the deflection means uses a horizontal/vertical scanning method, corner deflection aberration will similarly occur, and both electromagnetic deflection and electrostatic deflection methods are possible. In particular, since the magnetic field generator generates an alternating magnetic field, it goes without saying that when placed behind the focusing lens, the electrostatic deflection method can reduce magnetic field coupling.
発明の効果
以上の様に本発明のビーム集束装置は、偏向手段の手前
に、４極磁界の補正磁界を発生させる磁界発生装置を設
ける事により、周辺のビームスポット径を改善する事が
出来、結果的には、゛補正する前の周辺限界解像度に対
比して、ビーム電流をφ 増加する事が
可能となり・輝度ア・プの効果も有する事となる。よっ
て高電流密度の投写管や、高精細度投写管に対し有益な
効果をもたらすものである。Effects of the Invention As described above, the beam focusing device of the present invention can improve the peripheral beam spot diameter by providing a magnetic field generating device that generates a correction magnetic field for the quadrupole magnetic field in front of the deflection means. As a result, it becomes possible to increase the beam current by φ compared to the marginal resolution before correction, and it also has the effect of increasing the brightness. Therefore, it has a beneficial effect on high current density projection tubes and high definition projection tubes.
第１図は従来例におけるビーム集束装置の構成図、第２
図は本発明の一実施例におけるビーム集束装置の構成図
、第３図は同装置の磁界発生装置の構造図、第４図は同
磁界の分布図、第５図は、従来ノ装置におけるビームス
ポットの形状図、第６図は実施例に於ける変調波形図で
ある。
１・・・・・・電子銃、２・・・・・・集束し／ズ系、
３・・・・・・ターゲット面、４・・・・・・偏向手段
、６・・・・・・磁界発生装置。
代理人の氏名 弁理士 中 尾 敏 男 は力Ｓ１名式Figure 1 is a configuration diagram of a conventional beam focusing device;
3 is a structural diagram of a magnetic field generator of the same device, FIG. 4 is a distribution diagram of the same magnetic field, and FIG. 5 is a beam focusing device in an embodiment of the present invention. The spot shape diagram and FIG. 6 are modulation waveform diagrams in the embodiment. 1... Electron gun, 2... Focused/Z system,
3...Target surface, 4...Deflection means, 6...Magnetic field generator. Name of agent: Patent attorney Toshio Nakao
Claims (1)
によって集束された電子ビームに水平および垂直走査を
与える偏向手段と、偏向されたビーム像を再生するター
ゲット面とを備え、ビーム軸に対して直角な平面に於け
る磁束密度の方向がビーム軸両側で異なり、かつ磁束密
度が中央で零となる制御磁界を発生する磁界発生装置を
前記偏向手段の手前に設け、前記磁界発生装置の磁束密
度を水平・垂直の周期で変調し、画面周辺のビームスポ
ット像を制御した事を特徴とするビーム集束装置。A focusing lens system for focusing an electron beam, a deflection means for giving horizontal and vertical scanning to the electron beam focused by the focusing lens system, and a target surface for reproducing a deflected beam image, A magnetic field generator that generates a control magnetic field in which the direction of magnetic flux density in a perpendicular plane is different on both sides of the beam axis and the magnetic flux density is zero at the center is provided in front of the deflection means, and the magnetic flux density of the magnetic field generator is A beam focusing device that modulates the beam spot image around the screen by modulating it in horizontal and vertical cycles.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13035384A JPS618833A (en) | 1984-06-25 | 1984-06-25 | Beam focusing device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13035384A JPS618833A (en) | 1984-06-25 | 1984-06-25 | Beam focusing device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS618833A true JPS618833A (en) | 1986-01-16 |
Family
ID=15032356
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13035384A Pending JPS618833A (en) | 1984-06-25 | 1984-06-25 | Beam focusing device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS618833A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5039923A (en) * | 1988-10-19 | 1991-08-13 | Hitachi, Ltd. | Focus adjusting device for projection display |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59119653A (en) * | 1982-12-27 | 1984-07-10 | Sony Corp | Beam spot correcting device |
-
1984
- 1984-06-25 JP JP13035384A patent/JPS618833A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59119653A (en) * | 1982-12-27 | 1984-07-10 | Sony Corp | Beam spot correcting device |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5039923A (en) * | 1988-10-19 | 1991-08-13 | Hitachi, Ltd. | Focus adjusting device for projection display |
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