(1) 200411707 玖、發明說明 (發明說明應敘明：發明所屬之技術領域、先前技術、内容、實施方式及圖式簡單說明) 技術領域 本發明係關於一種陰極射線管，其包括： 一顯示螢幕，用以接收一電子束且藉由該電子束來顯示 影像，該顯示螢幕包括衩數個發光圖像元素，其至少具有 兩種不同顏色； 一電子槍，其具有一用以將該電子束聚焦於該顯示螢幕 上的主透鏡，以及一用以產生該電子束的三極管區段，其 中於作業時，會形成一用以聚焦該電子束的前置聚焦電子 透鏡’讓位於該前置聚焦透鏡中之電子束外部的外緣光線 朝該電子槍的中央軸線向内折向，其折向程度大於該前置 聚焦透鏡中之電子束内部的内緣光線，因此該等外緣光線 將可趨近於該主透鏡的中夬軸線； 偏向構件，用以將該電子束於該顯示螢幕上之數條掃描 線中進行偏向，以便顯示該影像；及 顏色選擇構件，用以將該電子束導向該等圖像元素之至 少兩種不同顏色中其中一種顏色。 本發明亦關於使用於此陰極射線管中的電子槍 先前技術 的電子槍。 的具體實施例。在(1) 200411707 (1) Description of the invention (The description of the invention shall state: the technical field to which the invention belongs, the prior art, the content, the embodiments, and a brief description of the drawings) TECHNICAL FIELD The present invention relates to a cathode ray tube, which includes: a display A screen for receiving an electron beam and displaying an image by the electron beam, the display screen including a plurality of light-emitting image elements having at least two different colors; an electron gun having an electron beam for A main lens focused on the display screen and a triode section for generating the electron beam, wherein during operation, a front focusing electron lens for focusing the electron beam is formed to give way to the front The outer ray of the outer edge of the electron beam in the focusing lens is folded inward toward the central axis of the electron gun, and the degree of fold is greater than the inner ray of the inner beam of the electron beam in the front focus lens. Approaching the center axis of the main lens; a deflecting member for deflecting the electron beam in several scanning lines on the display screen to display the image And a color selection member for directing the electron beam to one of at least two different colors of the picture elements. The present invention also relates to an electron gun of the prior art used in this cathode ray tube. Specific embodiment. in
從US-A-4,620，134可發現此陰極射線管 該三極管區段中，會從陰極發射出 (2)200411707 發明說明績頁 的聚光點中。 偏向構件係配備於該電子槍與該顯示勞幕之間。作業 時，該等偏向構件的定址方式可讓該電子槍中 一 义成的電 子束於該顯禾榮幕上之數條掃插線中產生偏向。偏向 在該顯示螢幕的各角落處為最大，該陰極射線管中^產2 的最大偏向角纟數值於後文中將其稱為「最大偏向角度」。 於作業時，該電子束的掃插方式可讓每個該等圖像元素 依序接收到該電子束。從而可調整該電子束的電子束電 流’並且於該顯示螢幕上顯示—影像。 -般來說’該陰極射線管係彩：的陰極射線管，其中會 於該所謂@「同軸平面」中構成三條電子束，該些電子束 會於水平方向中彼此比鄰排％，每條電子束分別對應紅、 綠、藍三種顏色中的其中m。具備穿孔的陵影遮： 係位於接近該顯示勞I # Pi i條該等鲶 瓦恭的伋置，其同時可導引母π 子束朝具有對應顏色的闯 、、 巴的圖像元素前進。 七 該熟知的陰極射緩其 〆π營，其中 ^ 、、 耵、泉&具有所謂的像差衰滅三極& ^ 曰形成較強的前置聚隹 笔外緣光線朝 ι水焦电子透鏡，用以將該守外、豕 内折向，使得該等外 、卷褚内該電子From US-A-4,620,134, it can be found that the cathode ray tube and the triode section will be emitted from the cathode (2) 200411707 In the light collecting point of the description sheet of the invention. The deflection member is provided between the electron gun and the display screen. During operation, the positioning of these deflection members can cause a defined electron beam in the electron gun to be deflected in a number of scanning wires on the display screen. The deflection is the largest at each corner of the display screen. The value of the maximum deflection angle 纟 produced by the cathode ray tube 2 is referred to as the "maximum deflection angle" hereinafter. During operation, the scanning mode of the electron beam allows each of the image elements to sequentially receive the electron beam. Thus, the electron beam current of the electron beam can be adjusted and displayed on the display screen as an image. -In general, the cathode ray tube is a color cathode ray tube in which three electron beams are formed in the so-called @ "coaxial plane", and these electron beams are arranged next to each other in the horizontal direction. Each electron The beams correspond to m of red, green, and blue colors, respectively. Ling shadow cover with perforation: It is located close to the display device I # Pi i and other wagongs, which can simultaneously guide the mother π child beam toward the image element with the corresponding color, rush, and bar. . Seven well-known cathodes slow down their 〆π camp, where ^,, 耵, spring & have the so-called aberration decay triode & ^ ^ said to form a strong pre-polymerized pen with the outer edge of the light toward the water focus An electron lens, which is used to fold the outer and inner sides so that the electrons
卜綠先向會位於趨近該主透鉍W 槍之中央軸線的位w 〜说。 置，因而位於該電子束的内部 以 一般來說，對從距 來#入該透叙 離该光學中心較遠距離處進 的光線來說，透鏡 e以，根據該热 1碌形像差會比較大。所以 七 知的陰極射線管，兮 > 你用於其有 線上’ # 町於該_ 、、一 成王透鏡的球形像差效應會作用 琢前置聚焦電子诱# 減低該電子搶的整體球形像差：應：如此 透麵的球形像差效應之外的光 來 -6- (3) 200411707 螢幕上取得較小的聚光點，使得被顯示的影像具有較向的 清晰度。 該熟知陰極射線管的缺點係可於部份被顯示的影像中看 見干涉的人為電波，尤其是雲紋圖案。 發明内容 本發明的其中一項目的便係提供一種於開頦段务中所逑 類型的陰極射線管，其中可減低被顯示影像中的β、又圖 案’同時可維持較高的影像清晰度。 h 1 .其斗争；p企 藉由根據本發明之陰極射線管便可達成此目W 八 ^ 為該前置聚焦電子透鏡係被排列成於該電子束W ^ 、 a A灸外緣光線 流低於預設的臨界電子束電流時，減低該電于 朝内折向的程度。 •^輕·便七卜 一般來說，電子束電流較低時，該電子束的真 ^ 々 j成4氏 〇 較小，因為該等電子彼此之間的排斥作用會隨 ” § 電子束電流低於預設的臨界電子束電流時，也说尤％予束 的直徑較小時，該電子束的外緣光線被第二電子透知朝内 折向的作用便會過強。如此便會導致該等外緣光線被聚傳 於該第二電子透鏡與該偏向構件之間該中央軸線的第二交 錯點上。 當偏向該電子束時，該偏向構件對於該電子束亦可卷 备作 一電子透鏡，後文中將該透鏡稱為「偏向透鏡f。一奴 說’該偏向透鏡係一四極透鏡’當遠電子束經由較大 向角度被偏向時，其強度會隨之增強。 本發明係基於發現在該熟知的陰極射線管中，釉、 T何疋的 200411707 (4) 奋明說明績灵 偏向透鏡強度中，由第一方向中偏向透鏡所形成的第二交 錯點影像會實質聚焦於該顯示螢幕上。因此，該聚光點於 此偏向角度的第一方向中會具有特別小的直徑。 雲紋圖案係由於接近該顯示螢幕之陰影遮罩中的該等掃 描線與該等穿孔之兩個正常圖案之間的千涉所造成的。於 各種因素中，該雲紋圖案的調整深度會與垂直於該等掃描 線之方向中的聚光點尺寸有關。對該方向中較小的聚光點 尺寸而言，該雲紋圖案的調整深度便會增加。於特定的調 整深度中，干涉的人為電波便會出現於該被顯示的影像 中，並且降低該影像品質。 該等掃描線係被排列於水平方向中，而該第二交錯點的 影像則係形成於垂直方向中。因此，該垂直方向中特別小 的聚光點直徑變可能會使得在該被顯示的影像中看見干涉 的雲紋圖案，尤其是在亮度較低的影像區域中。 對特定的偏向透鏡強度（也就是對特定的偏向角度值）而 言，該效應最為明顯，因此該等雲紋圖案一般將會出現於 被顯示影像的環狀部份之中。 在根據本發明之陰極射線管中，該前置聚焦電子透鏡係 被排列成用以減弱較低的電子束電流之電子束的外緣光線 之朝内折向強度。於作業中，該第二交錯點係位於接近該 顯示螢幕的位置中，同時該垂直方向中的聚光尺寸會增 大，這係因為接近該第二交錯點的外緣光線的共同角度較 小的關係。從而該雲紋圖案會朝更大的偏向角度偏移，並 且較不明顯。 200411707 (5) 低於該臨界電子束電流，該主透鏡中的電子束直徑便會 非常小，足以使得能夠忽略會損及聚光點效能的球形像 差，因而便不需要完全朝内折向該等邊緣光線。 對高電子束電流而言，舉例來說實質大於預設的臨界電 子束電流的電子束電流，該電子束外緣光線的朝内折向實 質上並不會受到影響，因此便可於此高電子束電流時，於 減低球形像差中保持朝内折向的正向效應。因此，該聚光 點直徑並不會受到影響，並且對於所有該電子束電流值而 言，該被顯示的影像會比較清晰。 在一較佳的具體實施例中，該前置聚焦電子透鏡係由厚 度至少為0.5 mm之第一聚焦電極所構成的，「厚度」一詞 所指的係該電子槍中央軸線方向中的大小。 因為該第一聚焦電極的厚度相當大，所以該前置聚焦電 子透鏡的位置與該陰極相隔較遠的距離。因此該第二交錯 點會形成於距離該顯示螢幕較近的位置中。 該第二交錯點與該偏向構件之間的距離較佳的係能夠讓 該偏向透鏡的強度將該第二交錯點聚焦於該顯示螢幕上， 此時其對應的偏向角度便係大於該陰極射線管之最大偏向 角度。在此例中，該前置聚焦電子透鏡所引起的雲紋圖案 便會完全消失。 不過，增加該前置聚焦電子透鏡的厚度亦會增加其電子 -光學強度。該第一聚焦電極具備一讓該電子束通過的孔 徑，該孔徑於第一方向中較佳的直徑應該至少為0.7 mm。 該第一聚焦電極的孔徑大小如先前技術般的大，因此會補 200411707 篌;明謀明續頁 (6) 1綠的強度 償所增加的前置聚焦電子透氣 _ a冷；走 再者，輪4·沾：?丨.Μ舍 聚焦電極。 ♦係之厚度與該第一聚焦電極之 較佳的係，該第一聚焦也狂 β ,、τ α么〇 7。該平均直徑應該視為垂直 孔徑之平均直徑的比例约為υ· 與水平方向中直徑的平均值。 ，土 /说於的前置聚焦電子透鏡增強效 此時，因為增加厚度所導致白0 基 ^ π, 尤道致的前置聚焦電子透鏡減弱效Bu Lu first said that it would be located at the position w approaching the central axis of the main bismuth W gun. Is located inside the electron beam, so in general, for light entering from a distance far from the optical center, the lens e, according to the thermal aberration will be bigger. So Qizhi ’s cathode ray tube, you ’re using it on its wire line # # 于 于其 _, the spherical aberration effect of Yicheng King lens will act on the front focus electron lure # reduce the overall spherical shape of the electron grab Aberrations: Should: Light outside the spherical aberration effect of such a transparent surface comes to -6- (3) 200411707 A small spot of light is obtained on the screen, so that the displayed image has a more sharp direction. The disadvantage of this well-known cathode ray tube is that interference artifacts can be seen in part of the displayed image, especially the moiré pattern. SUMMARY OF THE INVENTION One of the objects of the present invention is to provide a cathode ray tube of the type used in Kailuan section, in which β and pattern 'in the displayed image can be reduced while maintaining high image sharpness. h 1. Its struggle; p can be achieved by a cathode ray tube according to the present invention. W ^ The front focusing electron lens system is arranged at the outer edge of the electron beam W ^, a A moxibustion. When it is lower than the preset critical electron beam current, the degree of the electric charge to be turned inward is reduced. • ^ Light and convenient. In general, when the electron beam current is low, the true beam diameter of the electron beam is smaller than 4 °, because the repulsion of these electrons with each other varies with the electron beam current. When the current of the electron beam is lower than the predetermined threshold, that is, when the diameter of the beam is smaller, the effect of the outer beam of the electron beam being folded inward by the second electron is too strong. As a result, the outer light rays are focused and transmitted at the second staggered point of the central axis between the second electron lens and the deflection member. When the electron beam is deflected, the deflection member can also be prepared for the electron beam. An electronic lens, which is hereinafter referred to as a "deflection lens f. One slave said that" the deflection lens is a quadrupole lens. "When the far electron beam is deflected through a larger direction angle, its intensity will increase accordingly. The invention is based on the discovery that in this well-known cathode ray tube, the glaze, T. Ho, 200411707 (4) Fen Ming shows that in the intensity of the deflection lens, the second interlaced point image formed by the deflection lens in the first direction will be substantial. Focus on that display. So The condensing point will have a particularly small diameter in the first direction of this deflection angle. The moire pattern is between the scan lines in the shadow mask close to the display screen and the two normal patterns of the perforations. Caused by various factors. Among various factors, the adjustment depth of the moiré pattern will be related to the spot size in the direction perpendicular to the scanning lines. For the smaller spot size in this direction The adjustment depth of the moiré pattern will increase. In a specific adjustment depth, interference artificial waves will appear in the displayed image and reduce the image quality. The scanning lines are arranged in the horizontal direction. The image of the second interlaced point is formed in the vertical direction. Therefore, a particularly small spot diameter in the vertical direction may cause interference moire patterns to be seen in the displayed image, especially Is in a lower brightness image area. This effect is most pronounced for specific deflection lens intensities (that is, for specific deflection angle values), so these moiré patterns will generally It is present in the ring portion of the displayed image. In the cathode ray tube according to the present invention, the front-focusing electron lens is arranged to attenuate the outer rays of the electron beam of a lower electron beam current. Inwardly folded strength. In operation, the second staggered point is located close to the display screen, and the spotlight size in the vertical direction will increase because it is close to the outer edge of the second staggered point. The relationship of the common angle of light is smaller. Therefore, the moiré pattern will shift toward a larger deflection angle and is less obvious. 200411707 (5) Below the critical electron beam current, the electron beam diameter in the main lens will be Will be very small enough to ignore the spherical aberrations that would impair the performance of the spot, so there is no need to fold these edge rays completely inward. For high electron beam current, for example, it is substantially larger than the preset The electron beam current of the critical electron beam current. The inward fold of the outer beam of the electron beam is not substantially affected. Therefore, at this high electron beam current, it can be kept inward while reducing the spherical aberration. Positive effect of folding. Therefore, the spot diameter is not affected, and the displayed image will be clearer for all the electron beam current values. In a preferred embodiment, the front focusing electron lens is composed of a first focusing electrode having a thickness of at least 0.5 mm, and the term "thickness" refers to the size in the direction of the central axis of the electron gun. Because the thickness of the first focusing electrode is quite large, the position of the front focusing electron lens is relatively far from the cathode. Therefore, the second interlaced point is formed in a position closer to the display screen. A better distance between the second staggered point and the deflection member enables the intensity of the deflection lens to focus the second staggered point on the display screen. At this time, the corresponding deflection angle is greater than the cathode ray. The maximum deflection angle of the tube. In this example, the moiré pattern caused by the front-focusing electron lens disappears completely. However, increasing the thickness of the front-focusing electron lens will also increase its electron-optical strength. The first focusing electrode has an aperture through which the electron beam passes, and a preferred diameter of the aperture in the first direction should be at least 0.7 mm. The aperture size of the first focusing electrode is as large as the previous technology, so it will make up 200411707 篌; Ming Mou Ming Continued (6) 1 The intensity of the green compensates for the increased front focus electron ventilation _ a 冷; go again, Wheel 4 · Dipping:? 丨 M focusing electrode. The thickness of the system is the same as that of the first focusing electrode, and the first focusing is also β, τ α. This average diameter should be considered as the ratio of the average diameter of the vertical pore diameter to the average of υ · and the diameter in the horizontal direction. The enhancement effect of the front focus electron lens at this time, at this time, the white 0 base ^ π due to the increase in thickness, especially the front focus electron lens weakens the effect
果，與因為放大開口而導致J 果，便會彼此實質抵銷。因此，可於與該陰極相隔較遠距 離處形成強度未變的前置聚焦電子透鏡，經過證κ其對万； 減少雲紋圖案特別有效。 一般來說，會於該第_聚焦^與該主透鏡之間配備一 第二聚焦電極，於作業中，該第二聚焦電極係由發散電子 透鏡所構成。 如果第一方向中該第一聚焦電極的開孔直徑與第一方向 中該第二聚焦電極的開孔直徑的比例介於0·9與I·5之間的 話’將會特別有利。 雖然熟習本技術的人士都熟知該第二聚焦電極，不過與 讓電子束通過之第二聚焦電極的孔徑比較起來’該第二聚 焦電極中之電子束的直徑非常的大。 因此，該發散電子透鏡對該電子束的影響祚常地大’並 且會進一步使得該交錯點更接近該顯示螢幕，且減少該等 外緣光束的共同角度。該電子束矸提供該主透鏡極佳的填 充效果，因而可防止發生球形像差，並且無法貫穿該第二 -10 - 200411707 ⑺ 發明說明續頁 聚焦電極。 在替代的具體實施例中，該前置聚焦電子透鏡係由一第 氷焦電極與一輔助聚焦電極所構成，該第/ I焦電極與 該輔助聚焦電極係排列於該電子槍之中央軸線中預設的共 同距離處，因此可於作業期間施加一電壓差於該第一聚焦 電極與遠輔助聚焦電極之間。 此具體實施例的作業方式與具有較厚之第一聚焦電極的 具體實施例作業方式相同，並且較容易製造。 貫施方式 在圖1所示之彩色陰極射線管中，會於電子槍1 0之二極 管區段15中產生三道電子束EBR、EBG、EBB。該等電子束 EBR ' EBG、EBB每一道分別對應紅色、綠色、藍色三種顏 色中其中一種，從該等顏色中便可產生一彩色影像。該等 電子束EBR、EBG、EBB係排列於圖中的平面中，一般稱為 「同轴」平面。 從三極管區段15中可看出，該電子槍10進一步包括，第 二聚焦電極G3，用以接收一聚焦電壓Vf ;以及/陽極G4 ’ 用以接收一陽極電壓Va。該主透鏡3 0係形成於該第二聚焦 電極G3與該陽極G4之間。舉例來說，該聚焦電壓Vf為6 kV，該陽極電壓Va為30 kV。 該等電子束EBR、EBG、EBB每一道都會經由該電子搶1〇 由該陽極電壓Va進行加速，並且在離開該電子槍1 〇之後’ 會於抵達該顯示螢幕5 0之前穿過偏向構件4 0。 該偏向構件40係排列成用以經由一預設的、變化的偏向 200411707 (8) 發明說明鳞頁 —__ 角度來偏向該等電予束EBR、EBG、EBB，以便讓該等電子 束EBR、EBG、EBB能夠照射於該顯示螢幕5〇之任何預期的 圖像疋素上。陰影遮罩4 5係排列於該顯示螢幕5 〇附近，其 配備著多個電子束穿孔圖案，該等穿孔圖案的排列方式可 讓每道電子束EBR、EBG、EBB都僅能照射於對應顏色的圖 像元素上。 圖2所示的顯示螢幕5 0係觀看者從外面看過去的情形。 在該熟知的陰極射線管中，該影像會受到該顯示螢幕5〇之 貫質％狀邵份5 1中的雲紋圖案的千涉。該環狀部份5 1内的 圖像元素對應到特定的偏向角度。 如前面所述，該等看得見的雲紋圖案係因為具有小直徑 之掃描線圖案與該陰影遮罩4 5之穿孔圖案之間的強烈干涉 所造成的。該等掃描線之小直徑係因為該第二交錯點被該 偏向透鏡以特定偏向角度成像於該顯示螢幕50之上而造成 的。 圖3 a與3 b中顯示的係電子束EBG與該熟知的陰極射線管 之電子-光學系統。選擇電子束EBG僅係作為範例，後面所 述的部份同樣適用於其它的電子束EBR、EBB。 電子係從被燈絲1 7加熱的熱電子陰極1 6射出。被射出之 電子束EBG會經由第一電極G 1而聚焦於交錯點X 1。之後， 該電子束EBG會通過第二電極G2A ;第一聚焦電極G2B， 其會形成該前置聚焦透鏡20 ;以及第二聚焦電極G3，其會 形成該發散透鏡25。該第二電極G2A與該第一聚焦電極G2B 係連接在一起，並且於作業中會接收一前置聚焦電壓VP(舉 -12- (9) (9) 200411707 買 例來說，約800 V)。該第二聚焦 電極G3則會接收該聚”The effect and the J effect caused by the enlargement of the opening substantially offset each other. Therefore, it is possible to form a front focusing electron lens with unchanged intensity at a relatively long distance from the cathode, which has been proven to be effective in reducing moiré patterns. Generally, a second focusing electrode is provided between the first focusing lens and the main lens. In operation, the second focusing electrode is composed of a divergent electron lens. It is particularly advantageous if the ratio of the opening diameter of the first focusing electrode in the first direction to the opening diameter of the second focusing electrode in the first direction is between 0 · 9 and I · 5. Although those skilled in the art are familiar with the second focusing electrode, the diameter of the electron beam in the second focusing electrode is very large compared with the aperture of the second focusing electrode through which the electron beam passes. Therefore, the effect of the divergent electron lens on the electron beam is unusually large ', and will further make the interlaced point closer to the display screen, and reduce the common angle of the outer beams. The electron beam 矸 provides an excellent filling effect of the main lens, so that spherical aberration can be prevented from occurring, and cannot pass through the second -10-200411707 说明 Description of the Invention Continued Focusing electrode. In an alternative embodiment, the front-focusing electronic lens is composed of a first ice-focusing electrode and an auxiliary focusing electrode, and the first / first focusing electrode and the auxiliary focusing electrode are arranged in a central axis of the electron gun. Therefore, a voltage difference between the first focusing electrode and the far auxiliary focusing electrode can be applied during operation. The working method of this embodiment is the same as that of the embodiment having a thicker first focusing electrode, and it is easier to manufacture. Implementation method In the color cathode ray tube shown in FIG. 1, three electron beams EBR, EBG, and EBB are generated in the diode section 15 of the electron gun 10. Each of these electron beams EBR 'EBG and EBB corresponds to one of three colors of red, green, and blue, and a color image can be generated from these colors. The electron beams EBR, EBG, and EBB are arranged in a plane in the figure, and are generally called "coaxial" planes. It can be seen from the triode section 15 that the electron gun 10 further includes a second focusing electrode G3 for receiving a focusing voltage Vf; and / anode G4 'for receiving an anode voltage Va. The main lens 30 is formed between the second focusing electrode G3 and the anode G4. For example, the focusing voltage Vf is 6 kV, and the anode voltage Va is 30 kV. Each of the electron beams EBR, EBG, EBB will be accelerated by the anode voltage Va via the electron grab 10, and after leaving the electron gun 10, it will pass through the deflection member 40 before reaching the display screen 50. . The deflection member 40 is arranged to bias the electric beams EBR, EBG, and EBB through a preset and changing deflection 200411707 (8) Invention Description Scale Sheet-__ angle so that the electron beams EBR, EBG and EBB can be irradiated on any desired image element of the display screen 50. The shadow mask 4 5 is arranged near the display screen 50. It is equipped with multiple electron beam perforation patterns. The perforation patterns are arranged so that each electron beam EBR, EBG, and EBB can only illuminate the corresponding color Image elements. The display screen 50 shown in FIG. 2 is a situation in which a viewer looks at it from the outside. In the well-known cathode ray tube, the image is subject to the moire pattern in the display screen 50% of the solid shape 51. The picture elements in the ring portion 51 correspond to a specific deflection angle. As mentioned earlier, these visible moire patterns are caused by strong interference between the scan line pattern with a small diameter and the perforation pattern of the shadow mask 45. The small diameters of the scan lines are caused by the second interlaced point being imaged on the display screen 50 by the deflection lens at a specific deflection angle. The electron beam EBG shown in Figs. 3a and 3b and the electron-optical system of the well-known cathode ray tube are shown. The selection of the electron beam EBG is only an example, and the parts described later are also applicable to other electron beams EBR and EBB. The electrons are emitted from the thermionic cathode 16 heated by the filament 17. The emitted electron beam EBG is focused on the interlaced point X 1 through the first electrode G 1. Thereafter, the electron beam EBG passes through the second electrode G2A; the first focusing electrode G2B, which forms the front focusing lens 20; and the second focusing electrode G3, which forms the diverging lens 25. The second electrode G2A and the first focusing electrode G2B are connected together, and will receive a pre-focus voltage VP during the operation (for example, -12- (9) (9) 200411707 purchase example, about 800 V) . The second focusing electrode G3 will receive the poly "
Vf(舉例來說，6 kV) ^)。 ®系螢幕Μ之 該電子束EBG會聚焦於該環狀部份5 1内的卜 &卜。 t 彳象元素 上，在此例中係聚焦於該顯示螢幕5 0柬邊的圖 襄5 〇Vf (for example, 6 kV) ^). The electron beam EBG of the ® screen M will be focused on the bu & bu within the ring portion 51. The t image element, in this example, is the image focused on the border of the display screen.
Α、，|目系费I 對較高的電子束電流來說（圖3 a中的2 mA)匕 >者限，因此月匕 之上的聚光點具有極佳的品質。其直徑非_项 、十 心早束電流來 夠提供極佳的影像清晰度。不過，對較低的通丁 ㈣.........一……，丨、，因而會在，衾 被顯示的影像上產生雲紋圖案。 這係因為低電子束電流（也就是，低於預設的^界包# 束電流的電子束電流）會使得電子束EBG的Α仏又彳于^ 小。舉例來說，該臨界電子束電流約為〇·5 mA。 目前該前置聚焦透鏡20過強，並且會將該電子束EBG水 焦於該第二聚焦電極G3内的第二交錯點X2中。在該顯示 螢幕的東邊，該偏甸透鏡4 0的強度可讓該第一支錯點X 2貫 質聚焦成像於該顯辛勞幕50之上。 圖4 a與4 b所示的係根據本發明之陰極射線管具體實施例 内的電子光學系統。下表所示的便係於此陰極射線管中之 電子槍相對於先前技術之陰極射線管的修正情形： 先前技術 本發明 t(G2B) 〇.4 mm 0.8 mm x(G2B) 0.55 mm 1.0 mm y(G2B) 0.6 mm 1.4 mm A 0.70 0.67 -13- 200411707 (10) 發明說明:續:頁 y(G3) 1.0 mm 1.5 mm y(G3)/y(G2B) 1.67 1.07 在此表中，t表示的係該電子槍中央軸線方向中的電極 厚度，y表示的係垂直方向中的孔徑尺寸，X表示的係水平 方向中的孔徑尺寸，而A表示的係該電極厚度與水平及垂 直方向中的孔徑尺寸平均值之間的比例。 該第一聚焦電極G2B的厚度增加，該第一聚焦電極G2B 中的孔徑亦被放大，因此比例A幾乎沒有改變。因此，該 前置聚焦透鏡20的強度實質上與該熟知陰極射線管中的強 度相同，不過該前置聚焦透鏡20與該交錯點XI之間的距離 則增長。現在該電子束EBG於該前置聚焦透鏡20中的直徑 較大，所以該第二交錯點X2將會更接近該顯示螢幕5〇，因 此可於較大的偏向角度直中聚焦於該顯示螢幕5 〇之上。 在此同時，該第二聚焦電極G3具備一較小的孔徑，因此 該發散透鏡2 5會比較強。如此一來便會將該電子束EBg外 緣光線的共同角度降低至完全無法形成第二交錯點X2的程 度。因此在該被顯示的影像中便不會看見源自於該三極管 區段1 1 5中的雲紋圖案。 該三極管區段的替代具體實施例便係圖5中所謂的三腳 三極管區段1丨5。在此三腳三極管中，具備一厚度較小的 慣用第一聚焦電極G2B，以及一補助聚焦電極G2C。該等 電極G2B、G2C皆位於該中央軸線的預設距離處。 該辅助聚焦電極G2C會經由該第一電極G 1接地，因此不 必供應額外的電壓給該電子槍。該三腳三極管區段1 1 5比 200411707 (η) 發明說明續頁 較容易製造，而該前置聚焦透鏡可比得上第一具體實施例 中的前置聚焦透鏡。 該等圖式僅係概略圖，並未等比例縮放。雖然已經配合 較佳的具體實施例來說明本發明，應該瞭解的係，本發明 不應該受限於該等較佳的具體實施例。更確切地說，技術 熟練的人士所可能進行的全部變化情形皆涵蓋於隨附申請 專利範圍的範疇中。 明確地說，技術熟練的人士可以對本專利申請案中所提 到的實體數字進行修改，例如電極厚度、孔徑直徑、電極 間隔及/或外加電壓，以便能夠在該陰極射線管的聚光點 效果與雲紋圖案之間取得最佳的平衡。 圖式簡單說明 參考附圖加以解釋之後，將可更清楚本發明的所有觀 點。其中： 圖1所示的係一陰極射線管； 圖2為該熟知的陰極射線管之顯示螢幕的概略圖； 圖3 a所示的係該熟知的陰極射線管之電子光學元件於高 電子束電流下的作業情形； 圖3 b所示的係該熟知的陰極射線管之電子光學元件於低 電子束電流下的作業情形； 圖4a所示的係根據本發明之陰極射線管之電子光學元件 於高電子束電流下的作業情形； 圖4b所示的係根據本發明之陰極射線管之電子光學元件 於低電子束電流下的作業情形；及 -15 - 200411707 (12) 發明說明續頁 圖5所示的係該陰極射線管之替代具體實施例的三極管 區段。 圖式代表符號說明 10 電 子 槍 15 二 極 管 區 段 16 陰 極 17 燈 絲 20 前 置 聚 焦 透 鏡 25 發散 透 鏡 30 主 透 鏡 40 偏 向 構 件 45 陰 影 遮 罩 50 顯 示 螢 幕 5 1 環 狀 部 份 1 15 三 腳 三 極 管 區段 1 16 (未定義） EBR 紅 色 電 子 束 EBG 綠 色 電 子 束 EBB 藍 色 電 子 束 G1 第 一 電 極 G2A 第 二 電 極 G2B 第 一 聚 焦 電 極 G2C 輔 助 聚 焦 電 極 G3 第 二 聚 焦 電 極Α 、, | 目 系 费 I For higher electron beam current (2 mA in Fig. 3a), the d > limit, so the light spot on the moon has excellent quality. Its diameter is non-_term and ten heart early beam current is enough to provide excellent image sharpness. However, for the lower tongs ㈣ ...... a ..., 丨, a moiré pattern will be generated on the displayed image of 衾. This is because the low electron beam current (that is, the electron beam current lower than the preset ^ 界 包 # beam current) makes the electron beam EBG's Δ 仏 smaller again. For example, the critical electron beam current is about 0.5 mA. At present, the front focusing lens 20 is too strong, and the electron beam EBG will be water-focused on the second staggered point X2 in the second focusing electrode G3. On the east side of the display screen, the intensity of the polarized lens 40 allows the first misaligned point X 2 to be focused and imaged on the laborious screen 50. Figs. 4a and 4b show an electron optical system in a specific embodiment of a cathode ray tube according to the present invention. The following table shows the modification of the electron gun in this cathode ray tube relative to the cathode ray tube of the prior art: the prior art t (G2B) 0.4 mm 0.8 mm x (G2B) 0.55 mm 1.0 mm y (G2B) 0.6 mm 1.4 mm A 0.70 0.67 -13- 200411707 (10) Description of the invention: Continued: page y (G3) 1.0 mm 1.5 mm y (G3) / y (G2B) 1.67 1.07 In this table, t indicates Is the electrode thickness in the central axis of the electron gun, y is the aperture size in the vertical direction, X is the aperture size in the horizontal direction, and A is the electrode thickness and the aperture size in the horizontal and vertical directions. Ratio between averages. The thickness of the first focusing electrode G2B is increased, and the aperture in the first focusing electrode G2B is also enlarged, so the ratio A is hardly changed. Therefore, the intensity of the front focusing lens 20 is substantially the same as that in the well-known cathode ray tube, but the distance between the front focusing lens 20 and the staggered point XI increases. Now the diameter of the electron beam EBG in the front focus lens 20 is larger, so the second interlaced point X2 will be closer to the display screen 50, so it can focus on the display screen straight at a large deflection angle 5 〇 above. At the same time, the second focusing electrode G3 has a smaller aperture, so the diverging lens 25 will be stronger. In this way, the common angle of the rays outside the electron beam EBg will be reduced to such an extent that the second interlaced point X2 cannot be formed at all. Therefore, the moiré pattern originating from the triode section 1 15 will not be seen in the displayed image. An alternative embodiment of the triode section is the so-called triode section 11-5 in FIG. The triode includes a conventional first focusing electrode G2B with a small thickness and an auxiliary focusing electrode G2C. The electrodes G2B and G2C are all located at a preset distance from the central axis. The auxiliary focusing electrode G2C is grounded via the first electrode G1, so it is not necessary to supply additional voltage to the electron gun. The tripod section 1 1 5 is easier to manufacture than the 200411707 (η) invention description continuation sheet, and the front focus lens is comparable to the front focus lens in the first embodiment. These figures are only schematic diagrams, not scaled. Although the present invention has been described in conjunction with preferred embodiments, it should be understood that the present invention should not be limited to these preferred embodiments. Rather, all changes that may be made by a skilled person are covered by the scope of the accompanying patent application. Specifically, those skilled in the art can modify the physical numbers mentioned in this patent application, such as electrode thickness, aperture diameter, electrode spacing, and / or external voltage, so as to be able to achieve an effect at the spot of the cathode ray tube. Get the best balance with moire patterns. BRIEF DESCRIPTION OF THE DRAWINGS After explaining with reference to the drawings, all aspects of the present invention will become clearer. Among them: Fig. 1 is a cathode ray tube; Fig. 2 is a schematic view of a display screen of the well-known cathode ray tube; Fig. 3a is a high electron beam of the electron optical components of the well-known cathode ray tube Operation situation under electric current; Fig. 3b shows the operation situation of the electron-optical element of the well-known cathode-ray tube at low electron beam current; Fig. 4a shows the electron-optical element of the cathode-ray tube according to the present invention Operation situation under high electron beam current; Fig. 4b shows the operation situation of the electron optical element of the cathode ray tube according to the present invention under low electron beam current; and -15-200411707 (12) Description of the invention continued pages The triode section shown in 5 is an alternative embodiment of the cathode ray tube. Description of symbolic symbols 10 Electron gun 15 Diode section 16 Cathode 17 Filament 20 Front focus lens 25 Divergence lens 30 Main lens 40 Deflection member 45 Shadow mask 50 Display screen 5 1 Ring section 1 15 Triode section 1 16 (undefined) EBR red electron beam EBG green electron beam EBB blue electron beam G1 first electrode G2A second electrode G2B first focusing electrode G2C auxiliary focusing electrode G3 second focusing electrode
-16- 200411707 (13) 發明說明續頁 G4 陽 極 XI 交 錯 點 X2 第 -* 交 錯點 Vf 聚 焦 電 壓 Va 陽 極 電 壓 -17--16- 200411707 (13) Description of the Invention Continued G4 Positive pole XI Cross point X2-* Cross point Vf Confocal voltage Va Positive voltage -17-