GB2308223A - Colour selecting mechanism for a cathode-ray tube - Google Patents

Colour selecting mechanism for a cathode-ray tube Download PDF

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Publication number
GB2308223A
GB2308223A GB9625508A GB9625508A GB2308223A GB 2308223 A GB2308223 A GB 2308223A GB 9625508 A GB9625508 A GB 9625508A GB 9625508 A GB9625508 A GB 9625508A GB 2308223 A GB2308223 A GB 2308223A
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GB
United Kingdom
Prior art keywords
grid structure
cathode
frame
ray tube
selecting mechanism
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.)
Granted
Application number
GB9625508A
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GB9625508D0 (en
GB2308223B (en
Inventor
Kouji Hasegawa
Toshihiko Yamamoto
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sony Corp
Original Assignee
Sony Corp
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Filing date
Publication date
Application filed by Sony Corp filed Critical Sony Corp
Publication of GB9625508D0 publication Critical patent/GB9625508D0/en
Publication of GB2308223A publication Critical patent/GB2308223A/en
Application granted granted Critical
Publication of GB2308223B publication Critical patent/GB2308223B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/02Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
    • H01J29/06Screens for shielding; Masks interposed in the electron stream
    • H01J29/07Shadow masks for colour television tubes
    • H01J29/073Mounting arrangements associated with shadow masks
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2229/00Details of cathode ray tubes or electron beam tubes
    • H01J2229/07Shadow masks
    • H01J2229/0727Aperture plate
    • H01J2229/075Beam passing apertures, e.g. geometrical arrangements
    • H01J2229/0755Beam passing apertures, e.g. geometrical arrangements characterised by aperture shape
    • H01J2229/0761Uniaxial masks having parallel slit apertures, i.e. Trinitron type
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2229/00Details of cathode ray tubes or electron beam tubes
    • H01J2229/07Shadow masks
    • H01J2229/0727Aperture plate
    • H01J2229/0766Details of skirt or border
    • H01J2229/0772Apertures, cut-outs, depressions, or the like

Landscapes

  • Electrodes For Cathode-Ray Tubes (AREA)

Description

METHOD OF ASSEMBLING COLOUR SELECTING MECHANISM FOR CATHODE-RAY TUBE AND COLOUR SELECTING MECHANISM ASSEMBLED BY THE METHOD The present invention relates to a method of assembling a colour selecting mechanism for a colour cathoderay tube, and to a colour selecting mechanism assembled by the method.
Colour selecting mechanisms for colour cathode-ray tubes have been known, of a type in which a grid structure formed of a metal sheet having a plurality of slits (beam apertures) is mounted on a metal frame. A trinitron (trade name) type cathode-ray tube adopts a grid structure having linear apertures, which is called an aperture grille.
Figure 3 of the accompanying drawings is a perspective view of a colour selecting mechanism, and Figure 4 is an enlarged view of an essential portion of an aperture grille. An aperture grille 1 formed of a rectangular metal sheet has in an effective screen a plurality of slits 3 for allowing an electron beam to pass therethrough and tape portions 5 between these slits 3. The aperture grille 1 is mounted on a metal frame 7 formed in a rectangular shape by welding. The frame 7 includes a pair of parallel A members 9 which are curved and to which the aperture grille 1 is to be welded, and B members 11 each connecting both ends of each of the A members 9 to each other.
The aperture grille 1 is mounted on the frame 7 by the steps of pressing the frame 7 in the direction where the A members 9 are close to each other, and welding in such a state opposed sides of the aperture grille 1 each to the A members 9 at suitable intervals between welded points by seam welding or laser welding.
Next, by releasing the pressure applied to the frame 7, the aperture grille 1 is mounted on the frame 7 in a state of being stretched at a high tension. The reason why the aperture grille 1 is mounted in a stretched state is to reduce mislanding of electron beams passing through slits of the aperture grille 1 on a phosphor screen due to thermal expansion of the aperture grille 1 upon operation of the cathode-ray tube. An excess peripheral portion of the aperture grille 1 projecting from the frame 7 is removed by trimming, thus completing the mounting of the aperture grille 1 on the frame 7.
Recently, in colour selecting mechanisms with the trend toward high precision and light weight, it has been required to make the slit pitch finer and to make the aperture grille 1 thinner. This makes it difficult to mount the aperture grille 1 on the frame 7 in such a manner as to prevent occurrence of wrinkles by keeping the tape portions 5 in a suitable state, that is, in a state matched with the curved surfaces of the A members 9. For example, with respect to an aperture grille 1 having a thickness of 0.1 mm, when the pressure applied to the frame 7 is released, wrinkles do not occur if the slit pitch is set at 0.5 mm; however, they occur at a high occurrence rate if the slit pitch is set at 0.25 mm.The occurrence rate of wrinkles is also dependent on the thickness of the aperture grille 1, and more concretely, it tends to be increased as the thickness of the aperture grille 1 becomes thinner.
The intervals between welded points at which the opposed sides of the aperture grille 1 are welded to a pair of the parallel A members 9 by seam welding or laser welding, have been suitably set to prevent occurrence of wrinkles. In the aperture grille 1, when each interval between welded points is excessively widened, a stress is concentrated at each welded point due to a reaction force from the frame 7 from which the compression is released, tending to produce torsion and strain at each tape portion 5. On the other hand, when the interval between welded points is excessively narrowed, each tape portion 5 cannot absorb a difference in stress between adjacent welded points and thereby it tends to receive torsion and strain.
Accordingly, the related art method of assembling a colour selecting mechanism suppresses somewhat occurrence of wrinkles by setting the interval between welded points to prevent occurrence of wrinkles; however, it cannot positively reduce occurrence of wrinkles, which obstructs improvement in quality. Such a disadvantage of the related art method includes an inconvenience that a suitable interval between welded points must be determined each time there is a change of a condition (thickness and/or slit pitch) in the case of manufacturing the aperture grilles 1 under special specifications.
An object of the present invention is to provide a method of assembling a colour selecting mechanism for a cathode-ray tube, which is capable of setting an optimum interval between welded points for preventing occurrence of torsion and strain, thereby stabilizing the quality of the colour selecting mechanism and easily setting the interval between welded points even when there is a change of a condition (thickness and/or slit pitch).
Another object of the present invention is to provide a colour selecting mechanism assembled by the above method.
To achieve the first object, according to a first aspect of the invention, there is provided a method of assembling a colour selecting mechanism for a cathode-ray tube, comprising the steps of: preparing a grid structure formed of a square metal sheet having a plurality of slits extending in the direction perpendicular to a pair of parallel sides of said metal sheet; pressing a frame having a pair of members in parallel to each other in the same direction as that of said parallel sides of said metal sheet in such a manner that said members are close to each other; welding a pair of said parallel sides of said grid structure each to a pair of said members; and releasing the pressure applied to said frame and mounting said grid structure on said frame in a stretching state; wherein each of intervals "w" between welded points at which said grid structure is welded to said members is set to be in a range from 20 to 35 times a thickness "t" of said grid structure and from 8 to 14 times a pitch "p" of said slits.
To achieve the second object, according to a second aspect of the invention there is provided a colour selecting mechanism for a cathode-ray tube, comprising: a grid structure formed of a square metal sheet having a plurality of slits extending in the direction perpendicular to a pair of parallel sides of said metal sheet; and a frame having a pair of members in parallel to each other in the same direction as that of said parallel sides of said metal sheet; wherein said grid structure is installed to said frame by a pair of said parallel sides of said grid structure each to a pair of said members, said grid structure being mountable on said frame in a stretched state; and each of intervals "w" between welded points at which said grid structure is welded to said members is set to be in a range from 20 to 35 times a thickness "t" of said grid structure and from 8 to 14 times a pitch "p " of said slits.
Each of the above intervals between welded points may be set to be in a range from 24 to 29 times a thickness of the grid structure and from 8 to 14 times a pitch of the slits; or in a range from 20 to 35 times a thickness of the grid structure and from 10 to 12 times a pitch of the slits.
More preferably, each of the above intervals between welded points may be set to be in a range from 24 to 29 times a thickness of the grid structure and from 10 to 12 times a pitch of the slits.
In the present method of assembling a colour selecting mechanism for a cathode-ray tube and the colour selecting mechanism assembled by the method, each interval between welded points is set to be in the above specified range, and accordingly it is possible to ensure a degree of freedom for removing torsion and strain components around welded points and prevent a stress applied to each welded point from producing torsion and strain around the welded point, and hence to significantly reduce the occurrence rate of wrinkles occurring in the grid structure. As a result, it is possible to stabilize the quality of the colour selecting mechanism and to easily set the interval between welded points even when there is a change of a condition (thickness and/or pitch).
The invention will be further described by way of non-limitative example with reference to the accompanying drawings, in which: Figure 1 is an illustrative view of intervals between welded points at which an aperture grille is welded to a frame in accordance with an assembling method of the present invention; Figure 2 is a flow chart showing a procedure of assembling a colour selecting mechanism for a cathode-ray tube; Figure 3 is a perspective view of a colour selecting mechanism; and Figure 4 is an enlarged view showing an essential portion of an aperture grille.
Hereinafter, preferred embodiments of a method of assembling a colour selecting mechanism for a cathode-ray tube of the present invention will be described with reference to the drawings.
Figure 1 is an illustrative view of intervals between welded points at which an aperture grille is welded on a frame in accordance with the assembling method of the present invention, and Figure 2 is a flow chart showing a procedure for assembling a colour selecting mechanism for a cathode-ray tube. In addition, parts corresponding to those shown in Figures. 3 and 4 are indicated by the same characters, and the repeated explanation thereof is omitted.
As shown in Figures. 2 and 3, a colour selecting mechanism is assembled by the steps of cleaning a frame 7, mounting a spring holder 21 (see Figure 3) to the frame 7, pressing the frame 7 in such a manner that A members 9 to which the aperture grille 1 is to be welded are close to each other, and welding in such a state opposed sides of the aperture grille 1 each to the A members 9 by seam welding or laser welding.
Next, by releasing the pressure applied to the frame 7, the aperture grille 1 is mounted on the frame 7 in a state being stretched at a high tension. A portion of the aperture grille 1 projecting from the frame 7 is then removed by trimming, and the aperture grille 1 and the frame 7 are blackened, followed by mounting of the spring 23 and the like.
In the inventive assembling method, the aperture grille 1 is welded to the A members 9 at specified intervals "w" between welded points (see Figure 1). More specifically, the interval "w" between welded points is set to be in a range of from 20t to 35t (t: thickness of aperture grille 1) and from 8p to 14p (p: pitch of slits 3). Such a range of the interval "w" between welded points is determined in consideration of the fact that torsion and strain of the aperture grille 1 produced after release of the pressure applied to the frame 1 are dependent on the interval between welded points and also the interval between welded points varies depending on the plate thickness "t" of the aperture grille 1 and the pitch "p" of the slits.
Table 1 shows results of a test of examining occurrence rate of wrinkles for 17 inch type aperture grilles 1 (condition: specified as described below) which are each welded to frames 7 at different intervals between welded points.
Condition: thickness of aperture grille: 0.1 mm slit pitch: 0.25 mm Inspection of wrinkles: visual As is seen from the results shown in Table 1, the occurrence rate of wrinkles is significantly higher when the interval between welded points is out of a range of from 2.0 mm to 3.5 mm. This shows that these values define the borderlines of the significantly increased occurrence rate of wrinkles, and accordingly, the range between these values, that is, from 2.0 mm to 3.5 mm has a critical characteristic in terms of occurrence rate of wrinkles.
Table 1
interval between welded occurrence rate of wrinkles points points (centre to centre (occurrence number of between between welded points: mm) wrinkles/number of measurement) 1.8 11/20 1.9 9/20 2.0 1/20 2.2 0/20 2.4 0/20 2.6 0/20 2.8 0/20 3.0 0/20 3.2 1/20 3.4 1/20 3.5 1/20 3.6 8/20 The reason why the above range has the critical characteristic is as follows: namely, when the interval between welded points is less than 2.0 mm, a degree of freedom for removing torsion and strain around welded points is made smaller (in other words, a distance for absorbing strain is shortened); and when the interval between welded points is more than 3.5 mm, a stress applied to each welded point 25 is made larger, tending to produce torsion and strain of the tape portions 5 around the welded point.
With respect to the aperture grille 1, when the pressure applied to the frame 7 is released, wrinkles do not occur if the slit pitch is set at 0.5 mm; while they occur at a high occurrence rate if the slit pitch is set at 0.25 mm.
Accordingly, the occurrence rate of wrinkles tends to be increased as the slit pitch becomes smaller. Also, the occurrence rate of wrinkles tends to be increased as the thickness of the aperture grille 1 becomes thinner.
The range of the interval "w" between welded points can be converted in relation to these values (slit pitch "p", thickness "t") into a range of from 20 to 35 times of the thickness "t" and from 8 to 14 times the slit pitch "p".
Namely, by setting the interval "w" between welded points in the range of from 20 to 35 times the thickness "t" and from 8 to 14 times the slit pitch "p", it is possible to obtain an effect of significantly reducing the occurrence of wrinkles, so-called, a peak effect in terms of occurrence of wrinkles.
Table 2 shows results of a test of examining the occurrence rate of wrinkles for aperture grilles (condition: specified as described below) which are each welded to frames at intervals "w" between welded points in a range of 2.0 to 3.5 mm, wherein the number of measurement is increased more than that in the previous test.
Condition: thickness of aperture grille: 0.1 mm slit pitch: 0.25 mm Inspection for wrinkles: visual inspect Table 2
interval between welded occurrence rate of wrinkles points (centre to centre (number of occurrence of between welded points: mm) wrinkles/number of measurement) 2.1 1/100 2.2 1/100 2.3 1/100 2.4 0/100 2.8 0/100 2.9 0/100 3.0 1/100 3.1 1/100 As is seen from the results in Table 2, wrinkles do not occur when the interval between welded points is in a range of from 2.4 mm to 2.9 mm.This shows that the range between these value, that is, from 2.4 mm to 2.9 mm has a critical characteristic. As described above, the wrinkles occur in the aperture grille 1 depending on the slit pitch "p" and the thickness "t", so that the above range is converted in relation to these values into a range of from 24 to 29 times the thickness "t" and from 9.6 to 11.6 (10 to 12 by rounding the numerical value below 1.0) times the slit pitch "p". Namely, by setting the interval "w" between welded points in the range of from 24 to 29 times the thickness "t" and from 10 to 12 times the slit pitch "p", it is possible to obtain a significant effect of eliminating occurrence of wrinkles.
According to the above-described method of assembling a colour selecting mechanism for a cathode-ray tube, when the opposed sides of the aperture grille 1 are welded to the A members 9 of the frame by seam welding or laser welding while the frame 7 is pressed in such a manner that the A members 9 are closed to each other, the interval "w" between welded points is set to be in the range of from 20 to 35 times the thickness "t" and from 8 to 14 times the pitch "p", so that it is possible to significantly reduce the occurrence rate of wrinkles occurring in the aperture grille 1 after release of the pressure applied to the frame 7.
Moreover, by setting the interval "w" between welded points in the range of from 24 to 29 times the thickness "t" and from 10 to 12 times the pitch "p", it is possible to perfectly prevent wrinkles from occurring in the aperture grille 1 after release of the pressure applied to the frame 7.
Additionally, according to the above-described method of assembling a colour selecting mechanism for a cathode-ray tube, since the interval "w" between welded points can be set in relation to the thickness "t" and the pitch "p", it is not required to determine the interval "w" between welded points each time there is a change of a condition (thickness and/or slit pitch) in the case of manufacturing the aperture grilles 1 under special specifications, that is, it is possible to easily set an optimum interval "w" between welded points for preventing occurrence of torsion and strain even when there is a change of the condition (thickness and/or slit pitch).
While the preferred embodiment of the present invention has been described, such description is for illustrative purposes only, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the following claims.

Claims (12)

1. A method of assembling a colour selecting mechanism for a cathode-ray tube, comprising the steps of: preparing a grid structure formed of a square metal sheet having a plurality of slits extending in the direction perpendicular to a pair of parallel sides of said metal sheet; pressing a frame having a pair of members in parallel to each other in the same direction as that of said parallel sides of said metal sheet in such a manner that said members are close to each other; welding a pair of said parallel sides of said grid structure each to a pair of said members; and releasing the pressure applied to said frame and mounting said grid structure on said frame in a stretching state; wherein each of intervals "w" between welded points at which said grid structure is welded to said members is set to be in a range from 20 to 35 times a thickness "t" of said grid structure and from 8 to 14 times a pitch "p" of said slits.
2. A method of assembling a colour selecting mechanism for a cathode-ray tube according to claim 1, wherein each of said intervals "w" between welded points is set to be in a range from 24 to 29 times a thickness "t" of said grid structure and from 8 to 14 times a pitch "p" of said slits 3.
3. A method of assembling a colour selecting mechanism for a cathode-ray tube according to claim 1, wherein each of said intervals "w" between welded points is set to be in a range from 20 to 35 times a thickness "t" of said grid structure and from 10 to 12 times a pitch "p" of said slits.
4. A method of assembling a colour selecting mechanism for a cathode-ray tube according to claim 1, wherein each of said intervals "w" between welded points is set to be in a range from 24 to 29 times a thickness "t" of said grid structure and from 10 to 12 times a pitch "p" of said slits.
5. A colour selecting mechanism for a cathode-ray tube, comprising: a grid structure formed of a square metal sheet having a plurality of slits extending in the direction perpendicular to a pair of parallel sides of said metal sheet; and a frame having a pair of members in parallel to each other in the same direction as that of said parallel sides of said metal sheet; wherein said grid structure is installed to said frame by a pair of said parallel sides of said grid structure each to a pair of said members, said grid structure being mountable on said frame in a stretched state; and each of intervals "w" between welded points at which said grid structure is welded to said members is set to be in a range from 20 to 35 times a thickness "t" of said grid structure and from 8 to 14 times a pitch "p" of said slits.
6. A colour selecting mechanism for a cathode-ray tube according to claim 5 in which the grid structure has been installed to said frame by pressing said frame in such a manner that said members are close to each other, welding said pair of said parallel sides of said grid structure each to a pair of said members and releasing the pressure applied to said frame and mounting said grid structure on said frame in a stretched state.
7. A colour selecting mechanism for a cathode-ray tube according to claim 5 or 6, wherein each of said intervals "w" between welded points is set to be in a range from 24 to 29 times a thickness "t" of said grid structure and from 8 to 14 times a pitch "p" of said slits.
8. A colour selecting mechanism for a cathode-ray tube according to claim 5 or 6, wherein each of said intervals "w" between welded points is set to be in a range from 20 to 35 times a thickness "t" of said grid structure and from 10 to 12 times a pitch "p" of said slits.
9. A colour selecting mechanism for a cathode-ray tube according to claim 5 or 6, wherein each of said intervals "w" between welded points is set to be in a range from 24 to 29 times a thickness "t" of said grid structure and from 10 to 12 times a pitch "p" of said slits.
10. A method for constructing a colour selecting mechanism for a cathode-ray tube substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings
11. A colour selecting mechanism for a cathode-ray tube constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings
12. A cathode ray tube incorporating a mechanism according to any one of claim 5 to 9 or 11.
GB9625508A 1995-12-12 1996-12-09 Method of assembling colour selecting mechanism for cathode-ray tube and colour selecting mechanism assembled by the method Expired - Fee Related GB2308223B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP32296195A JPH09161672A (en) 1995-12-12 1995-12-12 Method for assembling color selecting mechanism for cathode-ray tube

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GB9625508D0 GB9625508D0 (en) 1997-01-29
GB2308223A true GB2308223A (en) 1997-06-18
GB2308223B GB2308223B (en) 2000-04-12

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CN (1) CN1073269C (en)
GB (1) GB2308223B (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6225736B1 (en) 1999-04-01 2001-05-01 Thomson Licensing S.A. Color picture tube having a low expansion tension mask attached to a higher expansion frame
US6274975B1 (en) 1999-04-01 2001-08-14 Thomson Licensing S.A. Color picture tube having a tension mask attached to a frame
US6455992B1 (en) 1999-04-12 2002-09-24 Thomson Licensing S.A. Color picture tube having a low expansion tension mask attached to a higher expansion frame
WO2002082493A2 (en) * 2001-04-07 2002-10-17 Thomson Licensing S.A. Method and apparatus for maintaining mask strand spatial uniformity for a crt

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100335091B1 (en) * 2000-05-30 2002-05-04 구자홍 Shadow mask in color braun tube
KR100335090B1 (en) * 2000-05-30 2002-05-04 구자홍 Shadow mask in color braun tube

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Publication number Priority date Publication date Assignee Title
US4806820A (en) * 1981-04-18 1989-02-21 Alcatel Nv Mask-frame assembly and method of manufacturing the same
US4828523A (en) * 1987-06-04 1989-05-09 Zenith Electronics Corporation Tension mask securement means and process therefore

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Publication number Priority date Publication date Assignee Title
KR940010981B1 (en) * 1992-05-20 1994-11-21 삼성전관 주식회사 Color cathode-ray tube

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Publication number Priority date Publication date Assignee Title
US4806820A (en) * 1981-04-18 1989-02-21 Alcatel Nv Mask-frame assembly and method of manufacturing the same
US4828523A (en) * 1987-06-04 1989-05-09 Zenith Electronics Corporation Tension mask securement means and process therefore

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6225736B1 (en) 1999-04-01 2001-05-01 Thomson Licensing S.A. Color picture tube having a low expansion tension mask attached to a higher expansion frame
US6274975B1 (en) 1999-04-01 2001-08-14 Thomson Licensing S.A. Color picture tube having a tension mask attached to a frame
US6455992B1 (en) 1999-04-12 2002-09-24 Thomson Licensing S.A. Color picture tube having a low expansion tension mask attached to a higher expansion frame
WO2002082493A2 (en) * 2001-04-07 2002-10-17 Thomson Licensing S.A. Method and apparatus for maintaining mask strand spatial uniformity for a crt
WO2002082493A3 (en) * 2001-04-07 2003-08-07 Thomson Licensing Sa Method and apparatus for maintaining mask strand spatial uniformity for a crt
US6781297B2 (en) 2001-04-07 2004-08-24 Thomson Licensing S. A. Method and apparatus for maintaining mask strand spatial uniformity

Also Published As

Publication number Publication date
GB9625508D0 (en) 1997-01-29
CN1165391A (en) 1997-11-19
JPH09161672A (en) 1997-06-20
GB2308223B (en) 2000-04-12
CN1073269C (en) 2001-10-17

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