Hermetically sealed container for large-sized precision sheet (semi-) product
A relatively light and generally resinous hermetically sealed container is provided for accommodating, supporting and transporting a precision sheet (semi-)product, such as a photomask, safely and in an airtight manner without exerting an inappropriate stress thereto, which precision sheet (semi-)product has such a large planar size that encounters an extreme difficulty in integral resin molding of a half of a container therefor. The container includes a main body and a lid member which are generally symmetrical with each other and respectively have sealing peripheries to be abutted to each other. Each of the main body and the lid member includes a plurality of resin-sheets which are disposed in a plane, abutted to each other at an intermediate joint boundary therebetween and joined with each other at the joint boundary. A reinforcing metal belt member is disposed from outside along the joint boundary and hermetically bolted to the resin sheets.
The present invention relates to a hermetically sealed container suitably used for transportation of a precision sheet (semi-)product, i.e., a precision sheet product or a semi-product thereof before completion of the product such as a (glass) substrate thereof, inclusive of a photomask (including a reticle) or a pelicle as a protective film for such a photomask, a semiconductor wafer-related product, various display products inclusive of a liquid crystal display (LCD),etc., particularly a large-sized precision sheet (semi-)product which is intended herein to mean one which has a large planar size including at least 750 mm for at least one side thereof and a container for which is composed of two halves each of which has such a planar size that integral resin molding thereof is extremely difficult.
A precision sheet (semi-)product as mentioned above is generally mechanically fragile in many cases, and a precision part or member formed thereon is further fragile in many cases. Moreover, in view of its properties in relation to its use, such a precision sheet (semi-)product extremely hates dirt, particularly adherent dirt of 0.3 μm or smaller, so that particular attention must be paid to hermetic sealability of a container therefor. Especially, such a sheet (semi-)product is frequently exported overseas from Japan by airplane, and minute dirt is liable to be introduced into the container due to a pressure difference between the inner space (particularly, a cargo space) of the airplane and the atmospheric pressure. Further, as the attachment of minute dirt should be avoided, the formation of a container main body with a foam resin (e.g., Japanese Patent Laid-Open Application (JP-A) 2001-31165) or the disposition of a foam resin cushioning material in a container as frequently exercised for general-purpose glass products since such a foam resin is liable to generate minute dirt due to abrasion. Further, such a precision sheet (semi-)product, particularly a display product or a photomask therefor, is inevitably enlarged in size (area) for complying with the demand for a large size and large area display, and further for allowing the exposure at one time of plural objective products, such as display products, with respect to the photomask product. Corresponding thereto, some new problems have occurred. That is, accompanying the size enlargement, the weight of a precision sheet (semi-)product per se as the content material is increased to 5-10 kg, and for supporting the weight while obviating the application of a stress to the precision sheet (semi-)product due to deformation of a container, the container is also required to have a substantial strength. However, if the container is composed of a metal material according to a conventional manner, the weight of the container is increased to 40 kg or more and the total weight thereof together with the content product is increased to 50 kg or more, so that the transportation thereof by human power becomes extremely difficult also due to the increase in outer contour size thereof. Further, even if the production of a resin-made container is intended for providing a smaller-weight container, and a container for a large-sized precision sheet (semi-)product having a large planar size of larger than 750 mm for at least one side thereof is intended to be composed of two halves, there has not been developed a resin molding technique which uses a mold allowing the molding of such a large-sized half until the present. Further, the accommodation of a precision sheet (semi-) product in a container has to be performed by supporting the (semi-)product so as to prevent at least one face thereof (on which precision members are formed) from contacting another member in the container.
SUMMARY OF THE INVENTIONAccordingly, a principal object of the present invention is to provide a generally resin-made, hermetically sealed container of a relatively light weight capable of safely accommodating and supporting therein a large-sized precision sheet (semi-)product, such as a photomask, which has such a large planar size that encounters an extreme difficulty in integral resin molding of a half of a container therefor, without exerting inappropriate stress to the (semi-)product.
According to our study for accomplishing the above object, it has been found possible to form a container adapted to the above object by adopting a structure of joining plural resin sheets disposed in parallel in a plane and ensuring an appropriate reinforcement and a hermetic seal structure. More specifically, according to the present invention, there is provided a hermetically sealed container for a large-sized precision sheet (semi-)product, comprising a main body and a lid member which are generally symmetrical with each other and respectively have sealing peripheries to be abutted to each other, wherein each of the main body and the lid member comprises a plurality of resin sheets which are disposed in a plane, abutted to each other at an intermediate joint boundary therebetween and joined with each other at the joint boundary, and a reinforcing metal belt member is disposed from outside along the joint boundary and hermetically bolted to the resin sheets.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Along the line 1C at which the abutting ends of the resin sheets 1a and 1b are abutted to each other, the resin sheets 1a and 1b are bonded to each other at their mutually abutting ends, and then an aluminum angle 5 of ca. 40 mm in width, ca. 20 mm in thickness and ca. 1300 mm in length is disposed as a reinforcing metal belt member and is fixed to the resin sheets 1a and 1b at 4 positions along the length thereof with two metal bolts 6 at each position. Then, a backing resin sheet 7 is bonded thereto to ensure a hermetic sealing.
For supporting and fixing (semi-)product sheet-holding members 4a and 4b along the periphery of the container A, as shown in
Further, two-division reinforcing metal belt members 5a and 5b are fixed by bolting and bonding of backing resin sheets (not shown) respectively along left and right sides and a central line crossing the reinforcing metal belt member 5 at right angles, and reinforcing sheets 10a and 10b are bonded to both side walls, respectively, of the container A. On the reinforcing sheets 10a and 10b, jigs (fixing members) 13a and 13b of a ratchet buckle lock 13 are fixed.
At the time of using the container A, a (semi-)product sheet B is set on the holding members 4b of the main body 12 placed horizontally, an O-ring 14 is disposed so as to surround the splint sheets 8h, and then the lid member 11 is caused to descend along the splint sheets 8h to sandwich the O-ring 14 between the lower end and upper end of the sealing periphery resin sheets 9a and 9b, respectively. In this state, the ratchet buckle locks 13 disposed along the periphery are closed to press the O-ring 14, thereby ensuring the hermetic sealing between the main body and the lid member. Incidentally, it is also preferred to apply an adhesive tape (not shown) onto an outer region S about the abutting boundary between the resin sheets 9a and 9b in order to increase the hermetic sealing performance. The resin sheets 10a and 10b function to provide an application region for such a tape for increasing the hermetic sealing in addition to allowing the attachment of the ratchet buckle lock jigs 13a and 13b as mentioned above.
The holding member 4b on the main body side comprises a (semi-)product sheet-abutting side wall 4ba having a height slightly smaller than the thickness of the (semi-)product sheet B and a tapered portion 4ba having a dowered taper angle of ca. 5 degs. The holding member 4a on the lid member side is different from the holding member 4b only in that it has no (semi-)product sheet-abutting side wall and has an upwardly tapered portion 4ab somewhat longer than 4bb. As a result of the presence of such tapered portions 4ab and 4bb, when a pressing force exerted by the ratchet buckle lock 13 is applied to the holding members 4a and 4B, the edge of the (semi-)product sheet B is rather shifted rightwards from its position contacting the side wall 4ba as shown in
(Material)
Explanation of materials of the respective parts is supplemented. The members or portions constituting the lid member 11 and the main body 12 other than the (semi-)product sheet-holding members 4a, 4b and the bolts 6a, 6b, i.e., the ceiling plate 1, the bottom plate 2, the backing resin sheet 7, the resin sheets 8a-8h, 9a and 9b, can comprise any thermoplastic resin but may preferably comprise an antistatic resin so as to obviate electrostatic attraction of minute dirt to a (semi-)product sheet contained therein. Known examples of such an antistatic resin having permanent antistaticity may include one having a composition of: (a) a hydrophilic polymer: 3-100 wt. parts, (b) a thermoplastic resin: 0-97 wt. parts (giving a total of 100 wt. parts together with (a)), and (c) a polyvalent metal compound: 0.001-0.5 wt. part (WO-A 03/033590), which composition is suitably used in the present invention. However, in case where an extreme level of optical property (prevention of haze) is not required, the addition of (c) a polyvalent metal compound is not required. It is particularly preferred to use (a) a hydrophilic polymer comprising a graft copolymer including a rubber trunk polymer having an alkylene oxide group, and an anionic surfactant (JP-A 59-2462), and further combine therewith a rigid thermoplastic resin, such as a polyacrylonitrile resin, a polystyrene resin or a polymethyl methacrylate resin, in order to provide a rigidity so as not to readily apply a warp stress to the (semi-)product sheet. Incidentally, in a specific example of the above-described embodiment, a ca. 5 mm-thick antistatic resin sheet comprising 10 wt. % of the above-mentioned hydrophilic polymer and 90 wt. % of a polyacrylonitrile resin (“BAREX 210”, made by BP Amoco) and exhibiting a flexural rigidity of 2 GPa., was used for providing the above-mentioned members.
The (semi-)product sheet-holding members 4a and 4b can also comprise an antistatic resin as mentioned above. In this case, the use of the bolts 6a and 6b can be omitted by bonding the holding member 4a and 4b of antistatic resin onto the resin sheets 8b and 8e.
As there is some gap (play) between the side wall 4ba of a holding member 4b and the edge of the (semi-)product sheet B, as mentioned above, some slide can occur between the edge of the (semi-) product sheet B and the tapered supporting positions 4ab and 4bb of the holding members 4a and 4b. Accordingly, it is further preferred to use a relatively soft resin having a slidability or a self-lubricating property, inclusive of a fluorine-containing resin such as polytetrafluoroethylene, an olefin resin such as polyethylene, or polyacetal resin, rather than the resin constituting the ceiling plate 1 or the bottom plate 2. In a specific example, holding members 4a and 4b made of polytetrafluoroethylene were used.
The reinforcing sheets 10a, 10b, 16 and 17 do not directly participate in hermetic sealing of the container and can therefore comprise an arbitrary rigid material inclusive of a metal. However, it is preferred that these sheet members are also made of a resin for providing a light container as a whole and made of an identical material as the resin sheets 8d, 8e, etc., for convenience of bonding.
As for the bonding between the resin sheets 1a and 1b forming the ceiling plate 1, the bonding between the resin sheets 2a and 2b forming the bottom plate 2, the bonding with these resin sheets of the backing resin sheet 7, and the bonding of the resin sheets 8a-8h, the bonding of the sealing periphery resin sheets 9a, 9b and the bonding of the reinforcing resin sheets 10a, 10b with the ceiling plate 1 and the bottom plate 2, it is possible to effect such bonding by using a separate adhesive resin, but there are few adhesive resins showing good antistaticity, so that a local lowering in antistaticity is liable to occur, if such an additional adhesive resin is used. Accordingly, in the case where the above-mentioned resin sheets are made of an antistatic resin, it is preferred to adopt solution bonding by using a good solvent for the antistatic resin to locally dissolve the antistatic resin sheets. Incidentally, in a specific example of the above-mentioned embodiment, it was confirmed that use of acetonitrile as a good solvent for polyacrylonitrile provided good bonding parts showing high bonding strength and antistaticity in combination. (However, as acetonitrile is toxic to some extent, the solution bonding should be performed by using a protector in an environment of good ventilation.)
The bolts 6 for fixing the reinforcing metal belt members 5, 5a and 5b to the ceiling plate 1 and the bottom plate 2, and the bolts 6a and 6b for fixing the holding members 4a and 4b to the resin sheets 8b and 8e, etc., can be made of either a metal or a resin. If resin-made bolts are used, it becomes possible to effect fusion bonding of the resin-made bolts to the corresponding resin sheets, and the fusion bonding of the resin-made bolts can provide a hermetic sealing effect thereby. However, in order to provide a container showing a better hermetic sealing performance, it is preferred use a backing resin sheet 7 and bonding it to the ceiling plate 1, etc., thereby improving the bonding strength and sealing performance between the resin sheets 1a and 1b, for example. The O-ring 14 (
(Other Modifications)
In the above, a horizontal-type container for a large-sized LCD-photomask has been described as a preferred embodiment. However, the above-described embodiment of container can be modified in various manners. Some examples of such modifications are described below.
For example, each of the ceiling plate 1 and the bottom plate 2 is formed by joining two resin sheets in the above embodiment but can be formed as a structure of joining 4 resin sheets as desired in order to obtain a large area of container.
Further, the ratchet buckle lock 13 used for fixedly binding the lid member 11 and the main body 12 to each other can be changed to another binding means as desired, and the number thereof and the number of pairs of holding members 4a and 4b can be increased or decreased as desired from 3 on each side and 12 in total in the above embodiment.
The reinforcing metal belt members 5 and 5a are in the form of aluminum angles in the above embodiment but can be made of, e.g., steel belts, as desired, by giving priority to the reinforcing effect, while aluminum or aluminum alloy is generally preferred in view of a good balance of lightness and strength.
In a specific example of the above embodiment, a container accommodating a photomask having a weight of ca. 15 kg by itself, weighed ca. 26 kg and measured ca. 1200 mm×1200 m in its state of transportation but could be carried into and out of various transportation means inclusive of airplanes by one or two people.
An Embodiment of Container for a Further large-Sized Precision Sheet (Semi-)Product In the above, there has been described an embodiment of hermetically sealed container suitable for accommodation and transportation of a precision sheet (semi-)product measuring at least 750 mm for at least one side. However, as for a container for a further large-sized and heavier precision sheet (semi-)product having a size of, e.g., at least 1000 mm for at least one side (e.g., a glass sheet measuring longitudinally ca. 1000 mm×transversely ca. 2000 mm×ca. 15 mm in thickness and having a weight of ca. 50 kg or larger), it is preferred to use a structure including securing holders at the bottom of a main body for holding a (semi-)product sheet more powerfully in X, Y and Z directions (assumed herein to correspond to longitudinal, transverse and thickness directions of the (semi-)product sheet) rather than the structure in the above-described embodiment of using the side walls of the main body and the lid member for the securing of the (semi-)product sheet.
Referring to
The securing holders (work locks) 54a, 54b and 54c have a function of applying pressing forces onto a (semi-)product sheet (not shown) placed (temporarily) on the supports 55a, 55b, and 55c in a vertical direction (and in a horizontal direction) to securely hold the (semi-)product sheet immovably in any of the X, Y and Z directions, and a whole perspective view of a securing holder 54b (in its upright securing state) is shown in
Referring to FIGS. 7 to 9, the securing holder (work lock) 54b includes a pair of fixed legs 541 fixed to the bottom plate 53 and a movable part 542 axially and pivotally supported by the fixed legs 541. The movable part 542 includes a pair of movable legs 543 fixed to the fixed legs 541, a horizontal body or bar 544 affixed between upper positions of the pair of movable legs 543, toggle clamps 546 for securing the movable part 542 to the legs 541, horizontal pressing members 547 horizontally piercing through and attached to the horizontal body 544, and vertical pressing members 549 piercing through and attached to a supporting plate 548 which in turn is attached to the horizontal body 544.
Each horizontal pressing member 547 includes a knob 547a for its spiral movement in the horizontal direction, a frontal end 547b for pressing a horizontal end of the (semi-)product sheet and a medium part 547c connecting them. The medium part 547c includes a screwed portion (not shown) disposed in proximity to the knob 547a and a tubular portion disposed in proximity to the frontal end 547c and equipped with a spring (not shown) inside thereof. Each vertical pressing member 549 includes a knob 549a, a lower end 549b for pressing an upper face at an edge of the (semi-)product sheet and a screwed medium part 549c.
The securing holder 54b can be pivotally moved from its upright position shown in
The securing holder 54a is identical to the securing holder 54b except that the number of the horizontal pressing member 547 is decreased from 2 to 1 and the number of the vertical pressing member 549 is decreased from 4 to 2, because of its shorter length. Further, the securing holder 54c is identical to the securing holder 54a except that the horizontal pressing member 547 is further omitted.
The functions of the securing holders 54a, 54b and 54c are explained. Referring to
In this state, the (semi-)product sheet B and the securing holder 54b are placed in a positional relationship as shown in
Then, as shown in
Then, the securing holders 54a and 54c are operated in a similar manner to fix the (semi-) product sheet B in the X and Z directions (in
Then, an O-ring is placed in the O-ring-receiving groove 52a of the main body AA, and the main body AA having accommodated the (semi-)product sheet B is covered with a lid member which has a substantially similar structure as the main body AA including an identical planar shape except that it does not include the securing holders 54a-54c or the supports 55a-55c and is slightly shallower (i.e., has a smaller side wall height). Then, the main body and the lid member are bound to each other by using, e.g., buckle locks as illustrated in
The embodiment of container using securing holders described with reference to FIGS. 5 to 10 can also be modified in various manners, of course. For example, as for the securing holders 54 (54a-54c), the lower end 549b of the vertical pressing member 549 is explained to have a spherical shape so as to directly press therewith the upper face of the (semi-)product sheet B in the above embodiment, but the shape of the lower end of the vertical pressing member can be changed into any arbitrary shape in combination with a tapered sheet 549d, as shown in
Further, the embodiment of
(Further Modification)
In any of the above-described embodiments, it is possible to equip at least one of the main body and the lid member with at least one, preferably totally two or more, nozzles for replacement of gas inside the container. Such nozzles for replacement of gas inside the container, are suitable, e.g., for replacing the inside atmosphere of a container for a (semi-) product sheet, such as an EL(electro-luminescence)-related sheet product, which should be free from moisture in addition to the attachment of dirt.
As described above, according to the present invention, there is provided a relatively light and generally resinous container capable of accommodating, supporting and transporting a large-sized precision sheet (semi-)product, such as a photomask, which has such a large planar size that encounters an extreme difficulty in integral resin molding of a half of a container therefor, safely and in an airtight manner without exerting an inappropriate stress thereto.
Claims
1. A hermetically sealed container for a large-sized precision sheet (semi-)product, comprising a main body and a lid member which are generally symmetrical with each other and respectively have sealing peripheries to be abutted to each other, wherein each of the main body and the lid member comprises a plurality of resin sheets which are disposed in a plane, abutted to each other at an intermediate joint boundary therebetween and joined with each other at the joint boundary, and a reinforcing metal belt member is disposed from outside along the joint boundary and hermetically bolted to the resin sheets.
2. A container according to claim 1, wherein each of the plurality of resin sheets comprises an antistatic resin.
3. A container according to claim 1, wherein the main body and the lid member are provided with a pair of holding members for holding the precision sheet (semi-)product.
4. A container according to claim 3, wherein each sealing periphery of the main body and the lid member comprises a side wall and a support member for supporting thereon the holding member for holding the precision sheet (semi-)product, which side wall and support member are composed of a set of resin sheets bonded to the plurality of resin sheets.
5. A container according to claim 3, wherein one of said pair of holding members disposed on the main body and the lid member, respectively, comprises a tapered portion and an abutting side wall having a height smaller than a thickness of the precision sheet (semi-)product, and the other of said pair of holding members has a tapered portion longer than the tapered portion of said one holding member.
6. A container according to claim 1, wherein the main body is provided at its bottom with a securing and supporting structure for securing and supporting the precision sheet (semi-)product in mutually perpendicular X, Y and Z directions (that is, longitudinal, transverse and thickness directions of the precision sheet (semi-)product).
7. A container according to claim 6, wherein said securing and supporting structure comprises at least one pair of a support for supporting the precision sheet (semi-)product placed thereon and a securing holder for applying a pressing force to an edge portion of the precision sheet (semi-)product placed on the support in at least the thickness direction of the precision sheet (semi-)product.
8. A container according to claim 7, wherein the precision sheet (semi-)product and the main body both have a shape of rectangle, along at least one side of which the pair of the support and the securing holder is disposed.
9. A container according to claim 7, wherein said at least one pair of the support and the securing holder includes at least one securing holder capable of applying to the edge portion of the precision sheet (semi-)product a pressing force acting onto a side end of the precision sheet (semi-)product in addition to the pressing force in the thickens direction of the precision sheet (semi-)product.
10. A container according to claim 9, including a securing holder capable of applying to the edge of the precision sheet (semi-)product a pressing force acting onto the side end of the precision sheet (semi-)product in addition to the pressing force in the thickness direction of the precision sheet (semi-)product and disposed along one side of the rectangle, and also a guide support disposed at a position close to a side opposite to said one side so as to support the precision sheet (semi-)product in a manner of receiving the pressing force applied to the side end of the precision sheet (semi-)product.
11. A container according to claim 7, wherein each of said at least one securing holder comprises a leg fixed to a bottom of the main body and a movable part pivotably supported by the leg so as to allow a pivotal movement of the movable part between an upright position for fixedly holding the precision sheet (semi-)product placed on the support by applying a pressing force to the edge portion of the precision sheet (semi-)product in at least the thickness direction and a tumbled and open position for allowing the placement of the precision sheet (semi-)product on the support.
12. A container according to claim 1, wherein an O-ring for hermetic sealing is placed between the sealing peripheries of the main body and the lid member.
13. A container according to claim 1, wherein a backing resin sheet is disposed along the joint boundary between the plurality of resin sheets on a side opposite to the reinforcing metal belt member and bonded to the plurality of resin sheets, thereby forming a hermetically bolted joint structure.
14. A container according to claim 1, wherein the resin sheets are bonded to each other by solution bonding of locally dissolving the resin sheets with a solvent of the resin forming the resin sheets and abutting the locally dissolved parts of the resin sheets to each other.
15. A container according to claim 6, wherein an O-ring for hermetic sealing is placed between the sealing peripheries of the main body and the lid member.
16. A container according to claim 6, wherein a backing resin sheet is disposed along the joint boundary between the plurality of resin sheets on a side opposite to the reinforcing metal belt member and bonded to the plurality of resin sheets, thereby forming a hermetically bolted joint structure.
17. A container according to claim 6, wherein the resin sheets are bonded to each other by solution bonding of locally dissolving the resin sheets with a solvent of the resin forming the resin sheets and abutting the locally dissolved parts of the resin sheets to each other.
Type: Application
Filed: Nov 17, 2004
Publication Date: May 19, 2005
Inventors: Mikio Fukui (Kyoto-Fu), Shiro Arai (Fukushima-Ken), Takayuki Abe (Tokyo)
Application Number: 10/989,476