CN1062977C - Color picture tube with reduced primary and secondary moire - Google Patents

Abstract

An improved color picture tube, operable in a multistandard television receiver, includes a viewing screen, a shadow mask and an electron gun for generating and projecting three electron beams through the shadow mask and onto the screen. The screen includes phosphor lines that extend in a first direction. The electron beams are subject to deflection in the first direction and in a second direction, that is substantially perpendicular to both the first direction and the phosphor lines. The shadow mask includes elongated slit-shaped apertures that are aligned in columns that substantially parallel the phosphor lines. The adjacent apertures in each column are separated from each other by tie-bars in the mask, and the tie-bars in one column are offset from the tie-bars in adjacent columns in the first direction. The improvement includes the tie-bars in alternate columns lying on substantially straight lines that form an angle of approximately 2 degrees with respect to the second direction.

Description

Has the color picture tube that reduces main and secondary moire

The present invention relates to a kind of color picture tube, it has into the shadow mask of the slot-shaped perforate of column alignment, and each row perforate separates with the tie-rod in the shadow mask; Be specifically related to a kind of color picture tube, it can be worked in multiple standard TV receiver, has minimizing once reaches the tie-rod device of secondary moir on the whole screen of picture tube shadow mask.

Employed most color picture tubes had the line screen and comprised the shadow mask of slot-shaped perforate today.These perforates become column alignment, and the perforate of adjacency separates with the connecting plate or the tie-rod of cover mutually in each row.When shadow mask forms the dome-shaped profile of parallel a little picture tube picture plane intralamellar part profile, keep the integraty of this shadow mask, the effect of this kind tie-rod is very important.Tie-rod vertically the staggering of tie-rod in one row and direct neighbor row at row (vertical direction).When electron beam bump shadow mask, therefore shadow mask stop portions electron beam directly produces shade on the screen behind the tie-rod.

When electron beam heavily overlayed on the scanning direction of vertical this slit row (horizontal direction), it produced a series of bright dark horizontal line on screen.This bright dark horizontal line and shade that this tie-rod forms interact, and cause brighter reaching than the dark space, and it produces the ripple pattern on screen, be called moir (moire) pattern.The quality of image of shown picture on this pattern grievous injury screen.Utilize the ripple pattern of Fu Liye (Fourier) analysis and geometrical analysis shadow mask picture tube, the visuality that demonstrates ripple is mainly decided on the amplitude and the spacing of this ripple pattern.Ripple magnitude is decided on vertical spot size and tie-rod width.The ripple spacing is decided on the cycle repeatability of tie-rod alignment and the interference between scanning line period.

Preferably select shadow mask tie-rod interval and size, use the ripple pattern of any scanning situation to reduce to minimum television set.Change by a kind of pattern to the industry of multiple standard TV receiver, make this selections complicated, therefore must reach certain compromise and can accept moir in whole multiple standards mode acquisitions.The two kinds of scanning situations of using are interlacing and non-interlaced scanning at present.Following table represents to develop the standard (staggered and noninterlace) that the present invention considers.

Standard overscanning visual scan line visual scan line

PAL/SECAM NTSC

4/3 107％ 537(268) 453(227)

&#604/3&#62 119％ 483(241)

<<4/3>> 137％ 420(210) 359(180)

16/9 75％ 716(358)

&#6016/9&#62?83％ 647(324)

In the table, the level of 4/3 and 16/9 expression screen is to vertical the ratio of width to height.Indicate second row of overscanning, represent the vertically passing scanning amount of 4/3 standard transmission and the vertical scanning amount of 16/9 standard transmission.In 16/9 standard, corresponding over-scanning amount is arranged in a horizontal direction, to obtain 16/9 ratio.The third line is illustrated in visual scan line number in the standard P AL/SECAM transmission, and fourth line is illustrated in visual scan line number in the standard NTSC transmission.For example, have in the PAL transmission of 625 scan lines and 107% (one of percentage 107) overscanning, 537 visual scan lines are arranged on screen.Biao Zhun ﹠amp; #604/3﹠amp; #62 and＜＜4/3 respectively relative two 119% and the 137% sizable mode of amplifying.Because amplify, so observed number of scanning lines is less on the screen.， ﹠amp similarly; #6016/9﹠amp; #62 is the amplification mode of 16/9 standard.Numeral noninterlace mode in the bracket.In the actual TV machine, be used for the mode that fax communication transmission is considered, to Phase Alternation Line system only is 268 scan lines, and NTSC is 227, but, considering that concerning the calculating of Moire fringe noninterlace mode calculates the inappropriate staggered possibility that can produce some ripples in the television set, is of great use.

The existing proposal of many technical data reduces the ripple problem.Its most technology relates to such as to revise electron gun and deflection yoke, adjusts beam spot on the screen, and vertical dimension or rearrange the tie-rod position of shadow mask reduces electron beam scanning line and the beat of tie-rod shade or interactive possibility.The United States Patent (USP) of awarding to Barten on June 14th, 1988 illustrates a kind of shadow mask the 4th, 751, No. 425, and wherein tie-rod is positioned at the horizontal deflection direction is become on the straight line at 3 to 8 degree angles.Though such as the illustrated technology of Barten, successfully obtain the minimizing of some ripples in the past, it is absorbed in ripple spacing of correction, and the secondary ripple spacing that does not have consideration when tie-rod line gradient is introduced, to be taken place.Therefore, the improvement ripple minimizing technology that needs to consider secondary ripple spacing is still arranged.This improving technology to the desired renewal of high-definition television more the high-quality colour camera tube especially need.For example, along with the electron gun quality improvement meets the more needs of high-definition television, this kind improvement electron gun produces littler electron-baem spot on screen.Reducing of electron-baem spot size produces visible sharper keen scan line on screen, itself and tie-rod shade interact and increase the problem of ripple pattern observability.

According to modified form color kinescope of the present invention, comprise a video picture screen, a shadow mask, and one be used to produce and throw three electron beams arrive screen by shadow mask electron gun.This screen is included in the phosphorus line that extends in the first direction.Electron beam is subjected to the deflecting action of the second direction of first direction and approximate vertical first direction and phosphorus line.This shadow mask comprises almost parallel phosphorus line and becomes the elongated slots shape perforate of column alignment.The perforate of adjacency separates with the tie-rod of shadow mask mutually in each row, and the tie-rod of Cheng Yilie in first direction with the tie-rod dislocation of adjacent column.This improvement place comprises: the tie-rod of conclusion of the business stagger arrangement is positioned on the roughly straight line of second direction into about 2 degree angles.

In the accompanying drawing:

Fig. 1 is the axial section end view of embodiment of the invention color picture tube;

Fig. 2 is the back plane figure of Fig. 1 kinescope panel;

Fig. 3 is a fraction of amplification diagram of Fig. 1 shadow mask.

Fig. 4 is the partial illustration of several angular relationships of presentation graphs 1 crt screen;

Fig. 5 is that a ripple spacing on the expression row gradient is to the chart of the relation of visual scan line;

Fig. 6 is illustrated in secondary ripple spacing on the row gradient to the chart of the relation of visual scan line;

Fig. 7 is that the expression embodiment of the invention is used for the chart of a ripple spacing of modified form shadow mask to the visual scan line; And

Fig. 8 is that the expression embodiment of the invention is used for the chart of the secondary ripple spacing of modified form shadow mask to the visual scan line.

Fig. 1 represents a rectangle colorful picture tube 10, and it has one and comprises rectangular faceplate 12, an and glass bulb (envelope) 11 of being made up of rectangle pars infundibularis 15 and the tubular neck portions 14 that is connected.This pars infundibularis 15 has the internal conductive coating (not shown), and this coating extends to neck 14 from negative electrode button 16.Panel 12 comprises a video picture panel 18 and a periphery flange or sidewall 20, and this sidewall 20 is with glass dust 17 and pars infundibularis 15 sealings.Three look phosphorus screens 22 are placed in the inner surface of video picture panel 18.Screen 22 is to have the phosphorus line to be arranged in three-way one group line screen, and each three-way one group comprises each look phosphorus line in three looks.Porous color is selected electrode or shadow mask, assembles movably with conventional apparatus, and screen 22 is formed the predetermined space relation.Electron gun 26 shown in the signal of Fig. 1 dotted line, it is assembled in center in the neck 14, produces and guide three electron beams 28 to arrive screen 22 along convergence path by shadow mask 24.

The design fits one external magnetic deflection yoke of Fig. 1 picture tube uses, such as near the yoke pars infundibularis and neck junction 30.When starting, this yoke 30 makes three electron beams 28 be subjected to influence of magnetic field, causes electron beam level and scanning vertically in the rectangular raster of screen 22.The initial plane (zero deflection place) of deflection is about the center of yoke 30.Because scattered field, the camera tube deflecting region is in yoke 30 extends axially the zone of electron gun 26.For simplicity, the actual curvature that does not show deflection beam path in the deflecting region at Fig. 1.

Shadow mask also is a part that comprises the face shield frame assembly 32 of peripheral frame 34.Face shield frame assembly 32 is to be positioned in the panel 12 shown in Fig. 1.Shadow mask 24 comprise a curve aperture portion 25, surround the nothing perforation boundary portion 27 of this aperture portion 25, and one from boundary portion 27 replications and from lateral margin (skirt) portion 29 of screen extension.Shadow mask 24 telescopic being enclosed within the whole framework 34 (as shown), and this side edge part 29 is welded to framework 34.

Fig. 2 and 3 knows clearly and shows shadow mask 24, has a rectangular periphery of two long limits and two minor faces.This shadow mask 24 has: a major axis X, and it is by shadow mask center and parallel long limit; And a minor axis Y, it is by shadow mask center and parallel short sides.This shadow mask comprises into the elongated slots shape perforate 36 of column alignment, this perforate almost parallel minor axis Y.The perforate 36 of adjacency separates with shadow mask tie-rod 38 in every row, and the interval of 38 of tie-rods in row is defined as the tie-rod spacing of ad-hoc location on the shadow mask.

The explanation of No. the 4th, 751,425, above-mentioned United States Patent (USP) can be positioned at the shadow mask tie-rod on the straight line that becomes 3 to 8 degree angles with the horizontal direction of electron beam scanning and reaches the minimizing Moire fringe.This tie bar angle reduces by a ripple spacing really.This ripple spacing P _N1Can calculate by following equation: ${\mathrm{<figure-callout\; id="1"\; label="P\; N"\; filenames="9510051100111.png,9510051100141.png"\; state="\{\{state\}\}">P</figure-callout>}}_N=\frac{\frac{P_v\&CenterDot;s}{2}}{\sqrt{\frac{{{\mathrm{<figure-callout\; id="2"\; label="P\; v"\; filenames="9510051100101.png,9510051100102.png"\; state="\{\{state\}\}">P</figure-callout>}}_v}^2}{4}{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="9510051100101.png,9510051100102.png"\; state="\{\{state\}\}">n</figure-callout>}}^2+s^2{m}^2-P_v\&CenterDot;\mathrm{sm}\&CenterDot;\mathrm{nCos}}}---\left(1\right)$ Wherein: P _vBe vertical shadow mask spacing, s is a scan line spacings, is tie-rod line angle of inclination, and n is the harmonic wave (that is: once, secondary, three inferior) of scan line frequency spectrum, and m is the harmonic wave (that is: once or secondary) of mask vertical spacing frequency spectrum.Shown in Figure 3 is negative tie-rod draft angle, and shown in Figure 4 be positive tie-rod draft angle θ.Fig. 4 is the sub-fraction of picture tube 10 screens 22, and it shows the three-way one group of electron beam excitation that is subjected to by cover perforate 36 of R-G-B phosphorus line.The short-and-medium horizontal line of Fig. 4 is the shade that the tie-rod 38 in the shadow mask 24 produces.

Fig. 5 is ripple spacing chart to the visual scan line, and its expression is created in has 0.68 millimeter vertical shadow mask spacing (P on the screen _v) two humorous filters of shadow mask ripple.This chart has 7 sets of curves of sign 0 degree to 6 degree.These curve representations are along formed angle between the straight line of tie-rod row and electron beam deflecting horizontal direction, and it is of No. the 4th, 751,425, above-mentioned United States Patent (USP).Can find out that by chart a ripple spacing minimizing is because tie-rod row gradient increases at arbitrary harmonic wave place.Yet tie-rod row gradient produces another kind of ripple and is called the secondary ripple.The secondary ripple is that the interference between the diagonal angle structure causes because scan line aligns with tie-rod.This secondary ripple is characterised in that an angle, and it can utilize following equation to judge from shadow mask level and vertical interval; $\&PlusMinus;\mathrm{\&Phi;}=\mathrm{ArcTan}\frac{\frac{P_v}{2}\&PlusMinus;P_H\mathrm{Tan}}{P_H}---\left(2\right)$ Wherein ± φ is the secondary tie-rod gradient that is produced (being respectively anticlockwise and clockwise) by tie-rod draft angle θ, P _vBe vertical shadow mask spacing, P _HIt is horizontal shadow mask spacing.Shown in Figure 4 be secondary tie-rod gradient+φ and-φ, and tie-rod draft angle θ.

Less two draft angles decision secondary ripples, this ripple have reduced on the screen limit of spot definition being focused be very obstinate.This secondary ripple spacing P _N2Can calculate by following equation: ${\mathrm{<figure-callout\; id="2"\; label="P\; N"\; filenames="9510051100101.png,9510051100102.png"\; state="\{\{state\}\}">P</figure-callout>}}_N=\frac{P_v\&CenterDot;s}{\sqrt{{P_v}^2{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="9510051100101.png,9510051100102.png"\; state="\{\{state\}\}">n</figure-callout>}}^2+s^2{m}^2-2P_v\&CenterDot;\mathrm{sm}\&CenterDot;\mathrm{nCos}}}---\left(3\right)$

Fig. 6 is the chart of secondary ripple spacing to the visual scan line, and two harmonic waves of secondary ripple are facilitated in its expression.This chart has 7 sets of curves, represents that also tie-rod is listed as the draft angle to the deflection level direction.From Fig. 6 chart as seen, the increase of secondary ripple spacing is because draft angle increases opposite with the effect of a ripple spacing.

Found that as seen ripple spacing of secondary ripple gap ratio easier.This is because during along horizontal scanning line, and tie-rod is shifted along diagonal (at angle φ place) is staggered.Therefore, for obtaining identical visual results, secondary ripple spacing need than a ripple spacing reduce less.Be different from 3 to the 8 tie-rod row gradients of spending that conventional art is advised, the present inventor finds, can the about 2 tie-rod gradients of spending obtain the improvement visual results.When 2 spent, though ripple ratio height when 3 spend, a ripple gap ratio secondary ripple spacing was more not obvious when this angle.Further, when 2 spent, the secondary ripple was separated the limit of resolution near human eyes.

Fig. 7 is that a ripple spacing of expression shadow mask constructed according to the invention is counted chart to the visual scan line.In this chart, vertical shadow mask spacing P _vBe 0.635 millimeter, and tie-rod draft angle θ is 2 degree.Do not represent first harmonic in the chart because the tie-rod reality of adjacent rows is with from being listed as to the P that is listed as in the shadow mask _v/ 2 is staggered.Therefore, this shadow mask frequency spectrum behavior is P as vertical interval _v/ 2, produce a s=P who allows more than 1200 visual scan lines _v/ 2 harmonic wave peak value.Fig. 7 solid line is a second harmonic, and other harmonic waves are represented with various broken strings.

Fig. 8 represents that a ripple spacing of shadow mask constructed according to the invention counts chart to the visual scan line.In this chart, vertical shadow mask spacing P _vBe 0.635 millimeter, and tie-rod draft angle θ is 2 degree.Fig. 8 solid line is a first harmonic, and other harmonic waves are to represent with various broken strings.

The method according to this invention is considered many factors, comprises the calculating for the needed tie-rod spacing of a plane shadow mask.The first, watch from video picture screen distance the last period, for known trace interval, calculate required tie-rod shadow positions at several places, Disengagement zone.These needed tie-rod shadow positions are the positions that are bordering on best compromise to the ripple that produces in each discrete district.Secondly, consider to decide the tie-rod shade on the corresponding screen, then, consider that shadow mask determines tie-rod spacing corresponding on the profile shadow mask that is shaped to the interval of screen in each discrete district in each discrete district place's electron beam deflecting angle.Then, calculate tie-rod spacing on the unfashioned flat cover by deducting stretching that the shadow mask forming step caused.This stretching be by form on the perforate shadow mask discrete district place's vertical interval physical measurement and this is measured and be shaped before judge doing on the flat cover to measure to compare.This judgement can comprise several iterative steps.Measure in case obtain to stretch, then this result makes it level and smooth with " least square " apolegamy.At last, on the flat cover tie-rod, carry out " least square " apolegamy.The evaluation of this apolegamy produces the flat cover tie-rod position that is used for any X, Y position.

Claims (1)

1. a color picture tube (10) comprising: a video picture screen (22), a shadow mask (24) and are used for producing and throwing three electron beams (28) arrive described screen by described shadow mask electron gun (26); Described screen is included in the phosphorus line that first direction extends, described electron beam described first direction, and the second direction of this first direction of approximate vertical and this phosphorus line on be subjected to deflecting action; Described shadow mask comprises by column alignment and elongated slots shape perforate (36) the described phosphorus line of almost parallel, in every row, be separated from each other in abutting connection with the tie-rod (38) of perforate with shadow mask, and the tie-rod in row forms dislocation with the tie-rod of adjacent column on described first direction, it is characterized in that:

The tie-rod of described conclusion of the business stagger arrangement (38) is placed in described relatively second direction and forms on the roughly straight line (37) at about 2 degree angles (θ).

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