JP2001246633A - Discontinuous surface lens, mold for molding it and mold processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discontinuous surface lens capable of being exposed to a phosphor layer so as to obtain a fluorescent surface for CRT having high grade characteristics, a mold capable of certainly molding the same and a mold processing apparatus capable of inexpensively processing the mold. SOLUTION: In the discontinuous surface lens 19, the adjacent parts 19b of two mirror planes 19a adjacent to each other are formed into a non-linear shape. The main mold part 20 of the mold is constituted by providing (M) mold split units 21 each having such a configuration that molding small planes 21a for forming the mirror planes 19a are arranged in one row along one end surface of a flat plate member and two molding small planes 21a adjacent to each other are connected through the non-linear adjacent parts 21b. The mold processing apparatus is constituted so as to perform the cutting processing of a material 22 to be processed while revolving a cutting tool 24 forming the molding small planes 19a in a predetermined revolving radius R.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens having a discontinuous surface such as an exposure correction lens used for forming a fluorescent screen of a CRT (cathode ray tube) by exposure, and molding the lens. And a processing apparatus for the molding die.

[0002]

2. Description of the Related Art Generally, a phosphor screen in which three phosphor layers of red, green and blue are regularly formed on the inner surface of a shadow mask type color cathode ray tube panel through an opening of a black light absorbing layer. The phosphor screen is usually formed by a photographic method using an exposure apparatus. As shown in FIG. 8, the exposure apparatus approximates a light source unit 1 and an exposure light beam 2 emitted from the light source unit 1 to a trajectory of an electron beam emitted from a cathode and deflected by a magnetic field during actual use. And a correction lens 3 for exposure. In this exposure apparatus, a CRT panel 7 on which a shadow mask 4 is mounted is installed so as to face the correction lens 3, and a photosensitive film or a phosphor slurry film formed on the inner surface of the panel 7 is applied to the correction lens 3. Exposure light beam 2 through shadow mask 4
Exposure.

The correction lens 3 needs to have a correction function for approximating the exposure light beam 2 to the trajectory of the electron beam for each of the exposure surfaces at different distances from the light source unit 1. A plurality of mirror planes 3a that are three-dimensionally inclined in the direction have discontinuous surfaces arranged in the row direction and the column direction. Correction lens 3 having such a shape
Is manufactured using a molding die as shown in FIG. 6 by molding with a thermoplastic resin or an ultraviolet curable resin.

[0004] The molding die includes a main die portion 8 and a sub die portion 9.
It is composed of The main mold part 8 includes the fixed frame 1 for assembly.
0, M × N mold dividing blocks 11 are arranged in M rows and N rows.
The mold division blocks 11 are inserted in the column arrangement, and the row-direction pressing plate 12 and the column-direction pressing bolt 17 that are pressed in the row direction x by screwing the row-direction pressing bolts 14 are inserted in the column direction. Receiving the pressing force from the row-direction pressing plate 13 pressed by y, it is fixed by the static friction force. Each mold division block 11
Has a shaping small plane 11a for forming a mirror plane 3a of the correction lens 3 on each upper end surface, and these shaping small planes 11a have a three-dimensional shape peculiar to a position where each is set. It has a slope. For example, the address at which each mold division block 11 is set is (i, j)
Then, the molding small plane 11 of each mold division block 11
a has a gradient of θx (i, j) in the row direction x and a gradient of θy (i, j) in the column direction y. On the other hand, the sub-mold portion 9 has a container shape having an opening corresponding to the fixed frame 10 for assembly, and has a resin injection port 18 provided on one side surface.

[0005] The molding die includes a main die portion 8 and a sub die portion 9.
After the molds are combined and clamped, the required molten resin is injected from the resin injection port 18 into the molding space between the small molding surface 11a of each mold division block 11 and the inner surface of the sub-mold portion 9. Is injected and the resin is cured to form the correction lens 3 described above.

[0006]

However, the above-mentioned molding die has a configuration in which small molding planes 11a for forming the respective mirror planes 3a of the correction lens 3 are provided in the individual mold division blocks 11. Further, each mold division block 11 has a shape having a shaping small flat surface 11a having a unique three-dimensional inclination on one end surface of a relatively small shaft-like body having a rectangular cross section. Therefore, in order to form the small molding surface 11a, processing requiring a high dimensional accuracy with an error of about 2 to 3 mm is required, and in manufacturing the mold divided block 11, the molding small surface 11a is mirror-finished. Requires cutting and polishing to finish. Accordingly, as a material of the mold division block 11, since a relatively small shaft-like body is subjected to processing requiring extremely high dimensional accuracy, it is necessary to use a hard and brittle material such as a cemented carbide, and material cost is reduced. Expensive. In addition, since all the mold split blocks 11 are individually manufactured by cutting and polishing, the number of manufacturing steps is increased and the processing cost is increased. Therefore, the above-mentioned molding die is considerably expensive.

Further, as shown in FIG. 7, when a shift occurs between the mold division blocks 11, the pressing forces of the pressing plates 12, 13 are not transmitted evenly as shown by arrows, so that the respective molds are not provided. The side surface of the divided block 11 is cut in rows and columns so as to be in close contact with the adjacent mold divided blocks 11.

In addition, the small forming surface 11a of each mold division block 11 in the above-mentioned forming die is mirror-finished by cutting and polishing as described above.
Since the side surface of each mold division block 11 is cut in row units and column units so as to be in close contact with the adjacent mold division blocks 11, each side of the mold division block 11 necessarily has a linear shape. Become. Therefore, since each mirror plane 3a of the discontinuous surface lens 3 of FIG. 8 formed by using such each mold division block 11 is continuously provided through a linearly adjacent portion, this discontinuity is caused. When the surface lens is used as the correction lens 3 of the exposure apparatus for forming the fluorescent screen of the CRT, the linearly adjacent portions of the mirror planes 3a become uneven and conspicuous, which is the quality of the fluorescent screen of the CRT. Is causing the decline.

When assembling the main mold part 8,
For example, if a foreign substance gets caught between the mold divided blocks 11, the pressing force of the pressing plates 12, 13 is dispersed, and the mold divided blocks 11 cannot be fixed in a predetermined arrangement. It is performed by precision work inside. Moreover, when assembling the main mold part 8, it is necessary to insert and position each of the mold division blocks 11 one by one into the assembly fixing frame 10, and insert all the mold division blocks 11. Thereafter, the row-direction pressing bolt 14 and the column-direction pressing bolt 17 must be screwed evenly and fixed so that the pressing forces from the row direction x and the column direction y become equal. Increase. These are factors that further increase the die cost.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has a discontinuous surface lens capable of exposing a phosphor layer so as to obtain a phosphor screen for a CRT having high quality characteristics. It is an object of the present invention to provide a molding die capable of reliably forming a surface lens and a die processing apparatus capable of processing the molding die at low cost.

[0011]

In order to achieve the above object, a discontinuous surface lens according to the present invention has a plurality of small mirror planes having different three-dimensional inclinations arranged on the surface in M rows and N columns. The mirror is characterized in that adjacent portions of each two adjacent mirror planes in at least one of the M row direction or the N column direction are formed in a non-linear shape.

When the phosphor of the CRT panel is exposed by using the discontinuous surface lens as a correction lens, the adjacent portions of two mirror planes adjacent to each other in at least one of the M-row direction or the N-column direction are non-contact. Due to the linear shape, the shadow of the adjacent portion is unclear unlike the linear shape, the unevenness of the shadow is reduced to almost inconspicuous, and a CRT panel having a high-quality phosphor screen is obtained. Becomes possible.

[0013] A molding die for molding a discontinuous surface lens according to the present invention includes a main die portion for forming each mirror plane of the lens, and a main die portion combined with the main die portion. And a sub-mold portion that forms a molding space between the main mold portion and the main mold portion. N mold splitting units arranged in a line along one end face of the mold and formed in a shape in which the two molding small planes adjacent to each other are connected via a non-linear adjacent portion, and It is characterized in that the mold dividing units are arranged in parallel with each other and fixedly inserted into the fixed frame for assembly in a close contact state.

In the molding die for a discontinuous surface lens, the sub-mold portion is united with the main mold portion and clamped to form a molding die surrounded by each molding small plane and the inner surface of the sub-mold portion. If the molten resin is injected into the space and cured, the discontinuous surface lens of the present invention in which the adjacent portions of the two mirror planes adjacent to each other have an arc shape can be surely formed. Further, in this molding die, since M molding small planes are formed in a relatively large flat plate-shaped division unit, it is possible to use a soft metal as a material of the mold division unit, thereby reducing material costs. Is considerably reduced, and since M molding small planes can be collectively formed, the number of man-hours for manufacturing the main mold portion is significantly reduced.
Furthermore, the main mold portion can be assembled without the need for precision work in a clean room, and the arrangement of all the molding small planes can be performed quickly, so that the number of assembly steps is reduced.

In the above-mentioned invention, a die working apparatus for cutting a die split unit in a die for forming a discontinuous surface lens holds a flat work material which is a raw material of the die split unit. A two-axis setting table for setting the material to be processed to a predetermined three-dimensional inclination by rotating each of the two axes about two orthogonal axes, and a cutting for forming the small forming surface by cutting the material to be processed A tool, and a processing machine for holding the cutting tool and rotating it at a predetermined rotation radius while sequentially transferring the cutting tool to each forming location of the small forming surface in the workpiece material. .

In this die machining apparatus, since the material to be processed is cut with a cutting tool that rotates with a predetermined rotation radius to form the molding small planes, the two molding small planes adjacent to each other are adjacent to each other. The portion can be formed in an arc shape corresponding to the turning radius of the cutting tool, and the die split unit of the main die in the forming die of the present invention can be precisely machined. Further, M mirror-shaped small flat surfaces for molding can be collectively formed on a plate-shaped workpiece by only M cutting operations of a cutting tool by a series of continuous operations of a two-axis setting table and a processing machine. The processing time required to form all the molding small planes is significantly reduced compared to the case where a mold divided block having one molding small plane is manufactured by cutting and polishing as in I do.

In the cutting tool of the die machining apparatus according to the present invention, the tip cutting part is formed in an arc shape having a predetermined radius, and the tip of the cutting part is formed with respect to a surface on which each small forming surface is formed in the material to be processed. It is configured to be positioned at a relative position where only the part is in contact, and to be transported a plurality of times at a predetermined pitch in a processing feed direction for performing a cutting operation each time the processing machine makes one turn, thereby processing one of the small forming surfaces. be able to.

With this, the cutting tool whose tip cutting portion has an arc shape having a predetermined radius is positioned so as to bring only the tip portion into point contact with the material to be processed. In this case, since the processing resistance is extremely small, there is no flaw caused by chipping of the cutting tool, etc., and one forming small plane is formed by multiple cuttings with the cutting tool. Thus, it is possible to form a small molding surface having an extremely precise mirror surface.

On the other hand, the cutting tool in the die working apparatus of the present invention has a rectangular shape having a width corresponding to the length in the arrangement direction on the small forming plane to be formed on the workpiece, and is formed by a working machine. It can also be configured to process one of the small molding surfaces by rotating.

As a result, a substantially right-angled corner is formed between the adjacent portion of each of the two molding facets adjacent to each other and the subsequent molding facet, and is processed by this die working apparatus. When a discontinuous surface lens formed by a molding die is used as an exposure correcting lens, a substantially right-angled corner is formed, and there is no possibility of shading. In addition, since this mold processing apparatus can form one small forming surface by one cutting of the cutting tool, the processing resistance increases by that much, but the transfer pitch of the cutting tool in the processing feed direction is large. As a result, the number of transfers is significantly reduced, so that the processing time can be greatly reduced.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a front view showing a discontinuous surface lens 19 according to an embodiment of the present invention. The discontinuous surface lens 19 includes a plurality of small mirror planes 19a having different three-dimensional inclinations, which are arranged in a row direction x.
M (example of 5) and N (example of 6) are arranged on the surface in the column direction y, and two mirror planes 19a adjacent to each other in the column direction y are provided. Adjacent part 1
9b has an arc shape. When the phosphor of the CRT panel is exposed using the discontinuous surface lens 19 as the correction lens 3, the adjacent portion 19b of each two mirror planes 19a adjacent to each other in the column direction y has an arc shape. The shadow of the adjacent portion 19b becomes indistinct and unevenness of the shadow is reduced to an almost inconspicuous level, so that it is possible to obtain a CRT panel having a high-quality phosphor screen.

The adjacent portion of each of the two mirror planes 19a adjacent to each other in the row direction x can also be formed in an arc shape. If such a discontinuous lens is used, a phosphor screen having higher quality can be obtained. A CRT panel having the same can be obtained. The adjacent portion 19b of the two mirror planes 19a adjacent to each other is not limited to the above-described arc shape, and the same effect as described above can be obtained if the mirror portion is a non-linear shape such as a curved shape.

FIG. 2 is an exploded perspective view showing an assembling process of a molding die capable of molding the discontinuous surface lens 19. In FIG. 2, the same reference numerals as those in FIG. It is attached. The main mold part 2 of this molding die
0 denotes M forming small planes 21 corresponding to one row in the row direction x.
a is formed integrally with the upper end surface of the plate-shaped member in a line along the longitudinal direction,
N pieces are arranged in the column direction y. Small forming surface 21a
Has a gradient θx in the row direction x and a gradient θy in the column direction y with respect to the reference plane, and the three-dimensional gradient is represented by an address (i, j) corresponding to the discontinuous surface lens 19. The values are set to unique values θx (i, j) and θy (i, j). Furthermore, two molding facets 21 adjacent to each other
The adjacent portion 21b between a has an arc shape.

Further, the row direction pressing plate 13 in the conventional mold is used.
Also, the column-direction pressing bolt 17 is not provided. Accordingly, the width of the assembly fixing frame 10 in the column direction y is reduced by substantially the thickness of the column direction pressing plate 13. In other words, the facing surface of the assembly fixing frame 10 in the row direction y is set slightly longer than the length of the mold dividing unit 21 and is inserted in a state where the mold dividing unit 21 is fitted. I have.

As shown by arrows in FIG. 2, the above-mentioned molding dies are fitted with N mold dividing units 21 in the fixed assembly frame 10 in a predetermined order, and all the mold dividing units 21 are inserted. After the insertion of the bolt, the row direction pressing bolt 1
By pressing each mold dividing unit 21 in the row direction x via the row direction pressing plate 12 by screwing in the main mold part 2, the mold dividing units 21 are fixed by static frictional force.
0 is completed. The sub-mold portion 9 is combined with the main mold portion 20 and clamped, and a molten resin is injected into a molding space surrounded by each molding small surface 21a and the inner surface of the sub-mold portion 9. Inject from 18. When the molten resin in the molding space is cured, the discontinuous surface lens 19 of FIG. 1 in which the adjacent portions 19b of the two mirror planes 19a adjacent to each other in the column direction y have an arc shape can be obtained.

In the mold division block 11 of the conventional mold, the end face of a shaft-shaped member having a relatively small rectangular cross section is subjected to cutting and polishing which requires extremely high dimensional accuracy. Therefore, it is necessary to use a hard and brittle material. On the other hand, in this molding die, a relatively large flat
In addition to forming M molding small planes 21a in one, the side surface of each mold dividing unit 21 can be ground in units of columns so as to match the side surface of the adjacent mold dividing unit 21 in the row direction x. As a result, as a material of the mold dividing unit 21,
For example, a soft metal such as an aluminum alloy, oxygen-free copper, or electroless nickel can be used, and the material cost is considerably reduced. In addition, the M small forming planes 21a can be formed at a time, the processing of the forming small planes 21a is made much easier by using a soft metal as a material, and the side surfaces of the mold dividing unit 21 are arranged in rows. And the row direction pressing plate 13 and the row direction pressing bolt 1
Since the step 7 is not required, the number of manufacturing steps of the main mold section 20 is remarkably reduced, and further, the mold cost can be significantly reduced in addition to the above-mentioned material cost reduction.

When assembling the main mold section 20, the flat mold dividing unit 21 is fixed to the fixed frame 10 for assembly.
Since it fits inside the mold, precision work in a clean room such as a conventional mold is not required, and all the small flat surfaces 21a can be quickly arranged. Can be fixed only by screwing in the row-direction pressing bolt 14, so that the number of assembling steps is reduced and the die cost can be further reduced.

Incidentally, a technique for forming a main mold portion by using a mold dividing unit having a plurality of small molding surfaces such as the above-described mold dividing unit 21 instead of the conventional mold dividing block 11. The ideas themselves have already been proposed by the applicant. However, in the mold dividing unit, the adjacent portion of each molding small plane has been considered to have a linear shape as in the case where the conventional mold dividing blocks 11 are arranged. The surface lens has the above-mentioned disadvantages, and has not been put to practical use.
Therefore, in order to obtain the discontinuous surface lens 19 as shown in FIG. 1, a plurality of molding small planes 2 in the molding die of FIG.
A necessary condition is to establish a processing apparatus capable of processing the continuous mold division units 21 in a line in a row via the arcuate adjacent portion 21b. Next, a mold processing apparatus capable of processing the mold division unit 21 of FIG. 2 will be described.

FIG. 3 shows the main mold part 2 in the molding mold of FIG.
1 is a perspective view showing a mold processing apparatus according to a first embodiment of the present invention for processing a mold dividing unit 21 which is a main component of No. 0. FIG. This mold processing apparatus includes a two-axis setting table 23 that holds a work material 22 of a mold division unit 21 and controls the attitude of a processing end surface (upper surface in the drawing) at a predetermined angle. Small molding surface 2
A diamond cutting tool 24 for cutting a mirror surface for cutting 2a, a tool holder 27 having the cutting tool 24 at its lower end, and a rotating disk 28 having the tool holder 27 attached to a peripheral end thereof in a suspended state. It is provided with.
As shown in FIG. 4 which is an enlarged perspective view of a main part of the die machining apparatus, the cutting tool 24 has a tip cutting portion having a predetermined radius r.
It has an arc shape.

The rotating disk 28 is configured such that a central mounting shaft 28a is connected to a spindle motor (not shown) of a processing machine (not shown) and is rotated. Is mounted at a position at a predetermined distance R from the center of the rotating disk 28, and is turned by a turning radius R. Further, the processing machine that rotates the rotating disk 28 by a spindle motor includes a three-axis orthogonal table that operates in the processing direction X, the processing feed direction Y, and the elevating direction Z,
When the cutting tool 24 is in a standby state at the retracted position in the elevating / lowering direction Z and the processing direction X, when the workpiece 22 is set on the two-axis setting table 23 and the three-dimensional inclination is set, The workpiece 22 is moved in the direction X and lowered along the vertical direction Z to cut the workpiece 22 and is intermittently transported at a predetermined pitch in the processing feed direction Y. The two-axis setting table 23 rotates the workpiece 22 around the α axis and the β axis passing through the center point thereof, and positions the processing end surface at a predetermined three-dimensional inclination angle.

In the above-mentioned mold processing apparatus, a control device (not shown) executes a control program based on preset control data to automatically control the two-axis setting table 23 and the processing machine. That is, the work material 22 is placed on the two-axis setting table 23 in a state where the cutting tool 24 is waiting at the retracted position in the elevating direction Z and the processing direction X by the operation of the processing machine. After that, the biaxial setting table 23
Is rotated about the α-axis, and the inclination θx (i, i) of the row direction x set in advance at the segment address (i, j) to be processed.
At the same time as tilting to j), it is rotated around the β axis to tilt in the column direction tilt θy (i, j) preset at the segment address (i, j).

Next, the processing machine moves the cutting tool 24 in the processing direction X while rotating it to position it directly above the portion to be cut in the workpiece 22, and then moves the cutting tool 24 by a predetermined distance in the elevating direction Z. , The workpiece 22 is started to be cut by the cutting tool 24, and then is intermittently transferred at a predetermined pitch in the processing feed direction Y. At this time, the cutting tool 24 is positioned at such a relative position that only the tip portion makes point contact with the workpiece 22 and cuts only an extremely small area by one rotation. Accordingly, the shaping small flat surface 22a formed by cutting on the surface of the workpiece 22 is prevented from generating a wave shape due to the transfer of an arc shape having a predetermined radius r at the tip cutting portion of the cutting tool 24, and is finished to a mirror surface. Can be

The cutting tool 24 is raised in the elevating direction Z each time the forming small plane 22a for a certain segment address (i, j) of the workpiece 22 is completed. The inclination with respect to the workpiece 22 by the table 23 is set, the cutting tool 24 is moved in the machining feed direction Y to a position facing the next segment address (i, j), and then lowered, and the workpiece 22 is lowered.
Is repeated. Work material 2
2, the above operation is repeated M times to form M molding small planes 22a, and one mold dividing unit 21 is completed.

In this mold processing apparatus, the adjacent portion 22b of the two small forming flat surfaces 22a adjacent to each other is cut by the cutting tool 2
4 can be formed in an arc shape corresponding to the turning radius R of the mold, and the mold dividing unit 21 of the main mold portion 20 shown in FIG.
Can be processed precisely. Further, in this die machining apparatus, a cutting tool 24 having a tip cutting portion having an arc shape having a predetermined radius r is used, and the cutting tool 24 is positioned so that only the tip portion is brought into point contact with the workpiece 22. Therefore, despite the use of diamond, which is susceptible to chipping, as the material of the cutting tool 24, since the cutting resistance is extremely small, there is no occurrence of scratches or the like due to chipping of the cutting tool 24 and the like. Tool 24
Forming small flat surface 2 by multiple cutting processes
Since 2a is formed, it is possible to form the small molding flat surface 22a having an extremely precise mirror surface.

Further, in this die machining apparatus, only two M-axis cutting operations of the cutting tool 24 by a series of continuous operations of the two-axis setting table 23 and the processing machine are performed, so that the M plate-like workpiece 22 has M mirror-like surfaces. Since the molding small plane 22a can be formed at a time, all the molding small planes can be formed in comparison with the case where a mold divided block having one molding small plane is manufactured by cutting and polishing like a conventional mold. Small plane 22a
The processing time required to form the material is greatly reduced.

The measurement results show that a cutting tool 24 having a nose radius r of 0.5 mm was used.
Is rotated by a spindle motor rotating at a rotation speed of 2000 rpm, and the peripheral speed of the cutting tool 24 is set to about 1000 m / mi.
n, and the intermittent feed speed in the processing feed direction Y is 5 mm
/ Min, one small flat surface 22a for molding
Processing time is about 1 minute, and one mold splitting unit 2
One processing time was about 1 hour. The surface roughness of the molding small plane 22a under this condition is Rmax 20 nm or less,
Further, the flatness of the molding small plane 22a was 0.05 μm or less. The small forming surface 22a after the cutting is formed has sufficient processing accuracy to be used as the small forming surface 21a of the mold dividing unit 21 without going through a polishing process.

FIG. 5A shows a mold according to a second embodiment of the present invention for processing a mold dividing unit 21 which is a main component of the main mold part 20 in the molding mold of FIG. It is a perspective view which shows the principal part of a processing apparatus. This mold processing apparatus is different from that of the first embodiment in that, instead of the diamond cutting tool 24 whose tip cutting portion has an arc shape having a predetermined radius r, a small molding tool for the mold dividing unit 21 is used. The use of a diamond cutting tool 29 having a front rectangular shape and a pointed triangular shape having the same width as the length in the arrangement direction of the planes 21a, and when the cutting tool 29 is intermittently transported in the machining feed direction Y The only difference is the transfer pitch of the two.

Therefore, in this die working apparatus, the working machine moves the cutting tool 29 in the working direction X to position the cutting tool 29 at a position directly above the segment address (i, j) to be machined in the work material 22. Axis setting table 23
When the cutting tool 29 is lowered by a set distance in the elevating direction Z after the three-dimensional inclination of the work material 22 is set by the A plane 22a is formed. Thereafter, the processing machine raises the cutting tool 29 to the retracted position, and in that state, moves the cutting tool 29 in the processing feed direction Y by a predetermined pitch corresponding to the length of the forming small flat surface 22a, so that the next segment address of the work material 22 is obtained. Is positioned just above (i, j),
The same operation as described above is repeated.

In this die machining apparatus, the adjacent part 22b of the two small molding surfaces 22a adjacent to each other is set to the turning radius R of the cutting tool 29, similarly to the mold processing apparatus of the first embodiment. It can be formed in a corresponding arc shape, and the mold dividing unit 21 of the main mold part 20 shown in FIG. 2 can be precisely machined. Further, as shown in FIG. 5 (b) showing a longitudinal section of the work material 22 in which the forming small plane 22a is cut, the adjacent portions 22b of each two forming small planes 22a adjacent to each other and the subsequent forming. A substantially right-angled corner portion 22c is formed between the small-use flat surface 22a. Since the portion between the adjacent portion 22b formed by the cutting tool 24 and the subsequent small forming surface 22a in the mold processing apparatus of the first embodiment has a curved shape, the curved portion is When a discontinuous surface lens molded using a molding die processed by a processing device is used as an exposure correction lens, there is a possibility that slight unevenness may occur. On the other hand, when a discontinuous surface lens molded by a mold machined by the mold machining apparatus of this embodiment is used as an exposure correction lens, a substantially right-angled corner 22c is formed as described above. Therefore, there is no danger of shading.

Further, the above-mentioned die working apparatus is provided with a cutting tool 29.
Since one molding small plane 22a can be formed by one cutting, the machining resistance is increased by that amount, but the transfer pitch of the cutting tool 29 in the machining feed direction Y is increased, and the number of times of transfer is significantly smaller. Therefore, the processing time can be greatly reduced. In an example, under substantially the same processing conditions as in the first embodiment, one mold dividing unit 21 is used.
The processing time can be greatly reduced to about 10 minutes, and a considerable cost reduction can be obtained.

[0041]

As described above, according to the discontinuous surface lens of the present invention, the adjacent portions of the two mirror planes adjacent to each other are formed in a non-linear shape. When the phosphor is exposed, the shadow of the adjacent portion becomes indistinct unlike the linear shape and the unevenness of the shadow is reduced to a level that is hardly noticeable, and a CRT panel having a high-quality phosphor screen can be obtained. It becomes possible.

According to the discontinuous surface lens forming die of the present invention, the main die portion is formed by forming M mirror-like forming small planes each forming a mirror plane along one end surface of the flat plate. Since the two molding small planes arranged in a row and adjacent to each other are formed using a mold dividing unit formed in a shape in which they are connected via a non-linear adjacent portion, each two adjacent small planes are adjacent to each other. The discontinuous surface lens of the present invention in which the portion adjacent to the mirror plane has an arc shape can be reliably formed. Further, in this molding die, since M molding small planes are formed in a relatively large flat plate-shaped mold dividing unit,
It is possible to use a soft metal as the material of the mold dividing unit, which significantly reduces the material cost and, since M molding small planes can be formed at one time, the man-hour for manufacturing the main mold part is significantly reduced. Reduce. Furthermore, the main mold portion can be assembled without the need for precision work in a clean room, and the arrangement of all the molding small planes can be performed quickly, so that the number of assembly steps is reduced.

Further, according to the mold processing apparatus of the present invention,
Since the material to be processed is cut with a cutting tool that rotates with a predetermined rotation radius to form the forming small plane, the adjacent portion of each two forming small planes adjacent to each other is rotated by the turning of the cutting tool. It can be formed in an arc shape corresponding to the moving radius, and the mold dividing unit of the main mold in the molding die of the present invention can be precisely machined.

[Brief description of the drawings]

FIG. 1 is a front view showing a discontinuous surface lens according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing an assembling process of a molding die for the discontinuous surface lens.

FIG. 3 is a perspective view showing a mold processing apparatus according to a first embodiment for processing a mold dividing unit of a main mold part in the molding die.

FIG. 4 is an enlarged perspective view of a main part of the mold processing apparatus.

FIG. 5A is a perspective view showing a main part of a mold processing apparatus according to a second embodiment for processing a mold dividing unit of a main mold part in the same molding die, and FIG. FIG. 4 is a vertical cross-sectional view of a cut mold dividing unit.

FIG. 6 is an exploded perspective view showing an assembling process of a conventional molding die.

FIG. 7 is a partial plan view showing the state of occurrence of a defect in the molding die.

FIG. 8 is a configuration diagram for explaining a use state of a discontinuous surface lens that can be formed by a molding die of the present invention.

[Explanation of symbols]

 Reference Signs List 9 Secondary mold part 10 Assembly fixed frame 19 Discontinuous surface lens 19a Mirror plane 19b Adjacent part 20 Main mold part 21 Mold dividing unit 21a Molding small plane 21b Adjacent part 22 Work material 23 Biaxial setting table 23a Small plane for forming processing material 24, 29 Cutting tool R Turning radius of cutting tool

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) // B29L 11:00 B29L 11:00

Claims (5)

[Claims] 1. A discontinuous surface lens having a plurality of small mirror planes having different three-dimensional inclinations arranged on the surface in M rows and N columns, wherein the lenses are adjacent to each other in at least one of the M row direction and the N column direction. A discontinuous surface lens, wherein adjacent portions of each of the two mirror planes are formed in a non-linear shape. 2. A molding die for molding the discontinuous surface lens according to claim 1, wherein a main die portion for forming each mirror plane of the lens, and the main die portion. And a sub-mold portion that forms a molding space between the main mold portion and the main mold portion. The main mold portion has M mirror-shaped molding surfaces each forming the mirror plane. N mold dividing units each having two small facets arranged in a line along one end face of a flat plate and having two adjacent small facets for molding connected via non-linear adjacent parts. A mold for forming a discontinuous surface lens, wherein each of the mold splitting units is arranged in parallel with each other and fixedly inserted into a fixed assembly frame. . 3. A die processing apparatus for cutting a die split unit in a die for forming a discontinuous surface lens according to claim 2, wherein the flat plate-shaped workpiece is a processing material of the die split unit. A two-axis setting table for holding the material and rotating it about two orthogonal axes to set the material to be processed at a predetermined three-dimensional inclination; A cutting tool for forming a flat surface, and a processing machine for holding the cutting tool and rotating it at a predetermined turning radius while sequentially transferring the cutting tool to each forming portion of the forming small plane in the workpiece material. A mold processing apparatus characterized by the above-mentioned. 4. A cutting tool according to claim 1, wherein a tip cutting portion is formed in an arc shape having a predetermined radius, and only a tip portion of said cutting portion is in contact with a forming surface of each forming small plane in a material to be processed. Position, and 1
The die processing apparatus according to claim 3, wherein the die processing apparatus is configured to be transported a plurality of times at a predetermined pitch in a processing feed direction in which the cutting is performed each time the rotation is performed to process one of the small forming surfaces. 5. The cutting tool has a rectangular shape having a width corresponding to a length in an arrangement direction on a small forming surface to be formed on a material to be processed, and is rotated by a processing machine once to form one cutting tool. The mold processing apparatus according to claim 3, wherein the apparatus is configured to process the small forming plane.