JPS63230206A - Manufacture of blank material for shadow mask - Google Patents

Abstract

PURPOSE:To freely control the magnitude of surface roughness, a shape and means interval of ruggedness of a blank material by performing the dull working of a rolling roll to work the dull working on the surface of blank shadow mask. CONSTITUTION:A laser beam generated by a laser beam generating and directing device L is passed through a conduit tube 1 and an expansion tube 2 provided its top end, then contricted on the surface of the rolling roll R by a focussing device 3 provided on the top end of the tube 2. The device 3 is supported by a supporting arm 5 capable of moving along the whole length of the roll R. Neighboring the device 3, the laser beam is reached the surface of the roll R through slits formed on a periphery of a chopper 8 freely capable of moving linearly along the longitudinal direction of the roll R rotatably in synchronized speed with the the arm 5. On the other side, the roll R is supported by a supporting device 4 freely rotatavely. Therefore, various surface roughnesses and shapes are generated by setting the roll revolution speed, moving speed of the arm 5 and chopper 9 and the size of chopper slit, and furthermore controlling the output of laser beam.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for manufacturing a shadow mask material for a color cathode ray tube, and in particular, to a method for manufacturing a shadow mask material for a color cathode ray tube. The present invention relates to a method of manufacturing a shadow mask material having a shape.

[Background of the invention]

Shadow masks are used as color-selecting electrodes in color TV Chiron cathode ray tubes. Low carbon Al-killed copper and rimmed steel have been used as materials for shadow masks, but recently an amber alloy material (Fe-56%Nl) having low thermal expansion characteristics has been considered useful.

The manufacturing process of the shadow mask is generally as follows. First, a shadow mask material having a predetermined thickness is manufactured through melting and casting of the material, appropriate steps such as rolling, and final cold working. The shadow mask material is etched and perforated to form a flat mask. The flat mask is annealed to give it a pressed bird shape, and is then pressed into a spherical shape. The spherical mask is subjected to a blackening process to become a shadow mask. There is also a method in which annealing to impart press formability is carried out immediately after final rolling, and this is called a pre-annealing method.

To explain in more detail, first, let's take low carbon AI killed filling as an example of a method for manufacturing shadow mask materials.
After the steel is melted in a converter, it is cast into an ingot, forged, then hot rolled and cold rolled, decarburized by open coil annealing, and then finally cold rolled to a predetermined thickness. Thereafter, it is slit to obtain a shadow mask material having a predetermined width.

In the case of invar material, it is similarly melted, then cast, and then forged, followed by hot rolling, followed by repeated cold rolling and annealing as needed, final cold rolling to a specified thickness, and slitting. A shadow mask material with a predetermined width is obtained.

After degreasing, the shadow mask material is coated with photoresist on both sides, a pattern is baked and developed, and then etched and perforated using an etching solution mainly containing ferric chloride.
Cut into individual pieces to make flat masks.

The flat mask is annealed in a non-oxidizing atmosphere to impart press formability (in pre-annealing this annealing is performed on the final cold rolled material before etching). After being leveled, it is formed into a spherical shape using a press.

Finally, the spherical mask is degreased and then subjected to a blackening treatment in a steam or combustion gas atmosphere to form a black oxide film on the surface. In this way, a shadow mask is produced.

[Prior art and its problems]

The above is the general manufacturing process of a shadow mask, but when manufacturing a shadow mask, the surface roughness and surface morphology of the shadow mask material are important points in the following points: First. , has a significant influence on the degreasing properties before applying the 7-otoresist to the shadow mask material. If degreasing is insufficient, the density M strength of the resist film decreases, which causes unevenness such as poor hole shape after etching. Second, if the surface roughness is not within the appropriate range, the resist film will peel off partially and proper etching holes will not be created, or conversely, it will stick too tightly and cannot be removed with a strong alkali after etching. The problem arises that it cannot be done. Thirdly, manufacturing a flat mask by etching perforations and subsequent press spherical molding is problematic (even if it is possible, depending on the surface morphology, the blackened film may easily peel off, and the peeled blackened film may have holes). This may cause serious defects such as blockage.

As described above, the surface roughness and morphology of the shadow mask material cause the above-mentioned phenomena regarding degreasing, resist IIQ adhesion, blackening film adhesion, etc. in subsequent steps.

Therefore, in order to prevent this phenomenon, shadow mask material manufacturers generally apply dull processing, which is a process that forms fine irregularities on the entire surface, to control the surface roughness, and then supply shadow mask materials to etching manufacturers and cathode ray tube manufacturers. ing. Currently, the dulling method used by material manufacturers is generally to dull the roll surface by shot blasting or electrical discharge machining, and roll processing using nine rolls.

By the way, etching manufacturers and cathode ray tube manufacturers each have different conditions such as lowering time, spray pressure during etching, blackening treatment conditions, etc. For this reason, the surface roughness and morphology of shadow mask materials suitable for each manufacturer's manufacturing conditions differ somewhat.

In view of this situation, material manufacturers are trying to accommodate the differences in these conditions as much as possible.
A need has arisen to control the surface roughness and morphology of the provided shadow mask. The trend toward higher definition shadow masks in recent years with the trend toward high-definition television has further increased this need.

However, current dull processing technology cannot meet this demand. As mentioned above, the dull processing methods currently used by material manufacturers are roll processing using shot blasting or electrical discharge machining.
It is possible to control the magnitude of surface roughness such as Ra and RzsRmax to some extent, but the period and form of surface roughness, Sm
It was not possible to freely control the average spacing of the surface irregularities, called . Further, dull rolling was carried out using a rolling roll that had been dulled by the shot blasting method.

The surface of the material inevitably has poor uniformity in surface morphology, and it is extremely difficult to avoid the occurrence of partially rough areas or areas that are not sufficiently rounded. Dull machining of rolls by electric discharge machining cannot create minute surface roughness such as R& of 1 μm or less, and it is far from possible to obtain Sm of 50 μm or more. In addition, dull processing required a huge amount of time and was impractical.

[Purpose of the invention]

In view of the above-mentioned points, the present invention can create a wider range of surface roughnesses and shapes than ever before, so that it can easily meet the various needs of manufacturers. The aim is to establish a dull processing technology for shadow mask materials that closely controls the distribution form.

[Structure of the invention]

As a result of repeated studies aimed at the above-mentioned purpose, the present inventors came up with the idea of sidling the rolls used in dull rolling by a laser processing method instead of the conventional method. It has been found that when a recess is formed using a laser processing method, a protuberance is formed around the periphery of the recess, and this protrusion may cause uniform dull processing in the shadow mask material. In addition, the laser machining method can freely control the intervals between the unevenness of the dull machining with a high degree of uniformity, and the machining time can also be greatly shortened compared to electric discharge machining. The unevenness of the dulling process also disappears, and a fine dulling pattern can be generated.

Since laser processing can be performed using a chimney collar, process control and condition changes are easily possible. There are many other benefits as well. As can be seen on the left, rolls processed by laser processing are much more suitable for processing shadow mask materials than conventional methods.1) Although the laser processing technology itself is well-known, No one has ever noticed this compatibility.

Thus, the present invention provides a method for dull rolling the surface of the shadow mask material using a rolling roll that has been subjected to cedar processing using a laser processing method when manufacturing a shadow mask leaf material. A method for manufacturing a shadow mask material is provided.

[Detailed description of the invention]

FIG. 1 shows a work situation in which a mill roll is subjected to dull processing using a laser processing method. A laser beam generated in a laser beam generation and directing device is directed into a laser beam conduit 1 .

The roll R to be dulled is rotatably supported by a roll support device 4. One of the roll shafts (here the right side) is joined to a drive shaft from a rotary drive (not shown). A telescopic tube 2 is provided at the tip of the beam conduit 1 via an expansion joint or in a nested manner, and a laser focusing device 3 is further attached to the tip of the tube 2 to focus the laser beam that has passed through the conduit 1 and the tube 2. The rolling roll converges to focus on the surface of the blade. The laser focusing device 3 is supported by a support arm 5. The support arm is movable over its entire length along the length of the roll by a suitable movement mechanism. The moving mechanism is shown here as being composed of a carrier 6 that carries the support arm, a screw 7 that moves it, and a drive motor M, but any other moving mechanism such as a sliding type or a self-propelled type may be used. Of course it is possible. In response to the movement of the support arm, the laser focusing device can be moved in the longitudinal direction of the roll and over the entire length of the roll. A chopper 8 is provided adjacent to the laser focusing device 3, which is rotatable and movable linearly along the longitudinal direction of the roll at a speed synchronized with the support arm. The laser beam reaches the roll surface through a slit formed around the chopper 8.

Therefore, the roll rotation speed, the movement speed of the support arm (and thus the laser focuser) and the thousand mitzvah, the chopper rotation speed,
By setting the size of the chopper slit and adjusting the laser output, various surface roughnesses and shapes can be easily created.

When a laser beam focused on the surface of a rolling roll is irradiated, the material in a circular area centered on the focal point melts, and as it expands, metal vapor spews out from the center, leaving a crater-shaped circular area in its wake. A hole is created. What is noteworthy is that an annular bulge is generated in a controlled manner along the periphery of the circular hole. This bump is
It can be used to dull the surface of a shadow mask.

These craters, which are dulled on the roll by laser processing, are generated over the entire roll with good reproducibility, and the size and depth of the craters as well as their distribution pattern can be freely controlled.The disadvantage of laser dulling lies in the fact that the craters can be freely controlled. It is. Moreover, it can be processed at high speed. These are significant advantages over conventional dulling methods.

FIG. 2 is an exaggerated depiction of one of the craters formed on the roll surface. A protuberance P is shown protruding from the roll surface.

In this way, dull rolling is performed on the shadow mask material using the dull rolling roll. Dull rolling may be applied to the material after the final cold rolling or at any pass stage during the final cold rolling, but the most efficient and effective method is to apply it to the material after the final cold rolling. This is done in the final pass of rolling, the previous pass, or both. It was found that the uniformity of the dulling pattern in the longitudinal direction was better when the final two passes were used.

Figure 3 schematically shows, for reference, the top view of the crater on the rolling roll, its cross-sectional outline, and the cross-section of the dull shape coined on the shadow mask material (in reality, the crater is not as neat as this). (Sometimes not). An annular depression coined by the roll ridge P on the shadow mask material and a somewhat raised protrusion in the center can be seen.

In the present invention, as a laser, a carbon dioxide laser, a ruby laser, etc., which are generally used for processing such as metal cutting and drilling, and welding, are used.

〔Effect of the invention〕

By manufacturing the shadow mask material using a rolling roll that has been dulled by laser processing, we can supply a shadow mask material that uniformly has the appropriate surface morphology according to various etching conditions and subsequent shadow mask manufacturing conditions. This makes it possible to respond to the trend toward higher definition shadow masks.

〔Example〕

Using the apparatus shown in FIG. 1, dull rolls having various surface shapes were produced by adjusting the chopper rotation speed, roll rotation speed, and laser beam output.

These rolls were used to roll Shadow Mask Lunar Eclipse Carbon A1 Killed Copper to a plate thickness of 12 mm. At that time, it was used only for the final pass of the final rolling, and not only the final pass but also the pass before the final lotus, for a total of 2. Two types of rolling were performed.

The surface roughness after rolling and the uniformity of the surface morphology in the longitudinal direction were investigated and are shown in Table 1.

In addition, some examples of rolling using dull rolls using the shot blasting method are shown.

In the table, Rz, Ra, and Sm follow the definitions and measurement methods established by JIS, etc., and are as follows: R3: This is called the ten-point average roughness, and is the part extracted by the standard length from the cross-sectional curve. , the average value of the elevation of the fifth highest mountain peak and the average value of the elevation of the fifth deepest valley, measured in the direction of vertical magnification from a straight line that is parallel to the average line and does not cross the cross-sectional curve. The value of the difference expressed in micrometers (μm).

Ra: Called the center line average roughness, a part of measurement length l is extracted from the roughness curve in the direction of the center line, the center line of this sampled part is the X axis, the direction of vertical magnification is the Y axis, and the roughness is When the curve is expressed as y=fCX), the value obtained by the following formula is expressed in micrometers (μm).

Sm: This represents the interval between irregularities in a cross-sectional curve, and although it has not been widely used in Japan, it provides information regarding the lateral direction of a cross-sectional curve. As shown in Figure 4, cross the cross-sectional curve at three adjacent points,
It is also the average value of the length Sml of the average line defined by the two points at both ends.

The uniformity of the surface morphology was evaluated as follows: After rolling, the surface roughness E (Rmaxb Ra, Rzs Sm) of the rear end of the coil approximately IQQOm away from the front end of the fill;
The surface morphology was investigated and judgments were made based on the magnitude of the difference.

As is clear from Table 1, in Invention Examples 1 to 5 using dull rolls processed by laser processing, arbitrary surface roughness gRz%Ra
It is possible to obtain Sm and Sm, and the uniformity in the longitudinal direction is excellent. Regarding the uniformity in the longitudinal direction, the case where dull rolling was performed in the final two passes of Example 4 showed the most severe results.

Examples 6 and 7 are examples after rolling with a dull roll by the shot blasting method, but the roughness such as RzXRa can be controlled by changing the grain size of shot, but the uniformity in the longitudinal direction is poor, and It is not possible to obtain the Sm value of .

In the present invention, Sm can be freely controlled from 20 to 160 in the embodiments, and in practice from 5 or more, whereas in the shot blasting method, it is restricted to a range of about 30 to 40.

In die machining using electrical discharge machining, it is currently possible to only obtain a material with an Ra of 12 to 15 μm or more, and only a small Sm, and it is not possible to freely control R1 and Sm.

[Brief explanation of drawings]

Fig. 1 is a partially cross-sectional perspective view of an example of an apparatus for dulling a roll by a laser method, Fig. 2 is a sectional view of a dulling crater formed by the laser method, and Fig. 3 is a An explanatory diagram showing the top surface of the crater, the cross-sectional contour, and the dull processing contour generated on the shadow mask material in relation to each other;
FIG. 4 is an explanatory diagram for defining Sm with respect to surface roughness. L: Laser beam generation and directing device 1: Beam conduction tube 2: Telescopic tube 3: Laser focusing device 4: Roll support device 5: Support arm 6: Carrier 7: Screw rod M: Motor 8: Chopper R: Roll 2nd r1

Claims (1)

[Claims] 1) In producing the shadow mask material, the surface of the shadow mask material is subjected to dull rolling using a roll that has been subjected to dull processing by a laser processing method. Method of manufacturing shadow mask material. 2) The method for manufacturing a shadow mask material according to claim 1, wherein the dull rolling is performed in the final pass and/or the previous pass during final cold rolling of the shadow mask material.