JP2013127382A - Method of measuring mechanical strength, and gripper used in the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of measuring the mechanical strength of a thin structure having a concave curved surface.SOLUTION: Fixtures for temporary chucks 31, 31 are used to sandwich at least one of a concave curved surface of a soft contact lens (thin structure) 51 while surface-supporting it by using support members 11 and 21 composed of elastic material, the fixtures for temporary chucks 31, 31 are attached to mechanical strength measuring device chucks (measurement sample attachment parts) 61, 61 for measuring the mechanical strength.

Description

  The present invention relates to a method for measuring the mechanical strength of a thin structure having a concave curved surface, and a gripping tool used in the method.

  The contact lens is required to measure a certain mechanical strength in order to satisfy the approval standard (Non-patent Document 1).

  For example, in the case of a soft contact lens, it is described that a tensile load is applied to a saturated swelled lens or a flat plate of the same raw material as the lens, and the strength is measured and evaluated. In addition, in the case of a hard contact lens, it is described that a compression bending test and an impact strength test are performed using a flat plate made of the same raw material as the lens or the lens, and the strength is evaluated.

No. 0428008 from Yakuhin Shokuhin, Director of Pharmaceutical Food Bureau, Ministry of Health, Labor and Welfare “Contact Lens Approval Criteria”

  However, the mechanical strength of the contact lens is measured exclusively using a flat plate of the same raw material as the lens or a strip-shaped test piece obtained by cutting the lens. This is because a method of measuring mechanical strength using a structure having a concave curved surface such as a lens as it is has not been developed yet. The chucking part provided in the mechanical strength measuring device is generally composed of a metal flat plate, and when the contact lens is chucked in the product shape, bending and cracking occur, and its mechanical strength Cannot be measured properly.

  However, even if the contact lenses are manufactured from the same raw material, the mechanical strength differs to a degree that cannot be ignored if the curvature of the lens curved surface is different. Therefore, a method for measuring the mechanical strength using a structure having a concave curved surface such as a lens as it is is desired.

  The present invention has been made in view of the above problems, and an object thereof is to provide a method for measuring the mechanical strength of a thin structure having a concave curved surface, and a gripping tool used in the method.

In order to solve the above problems, the present invention adopts the following configuration.
(1) A method for measuring the mechanical strength of a thin structure having a concave curved surface using a gripping tool provided with a first support member made of an elastic material and a second support member made of an elastic material, The holding member sandwiches the thin structure between the first support member and the second support member while supporting at least a part of the curved surface of the thin structure, and holds the thin structure. A mechanical strength measuring method in which a tool is attached to a measurement sample mounting portion of a mechanical strength measuring device to measure the mechanical strength of a thin structure.
(2) The measurement method according to (1), wherein the thin structure is sandwiched at two locations using the two gripping tools, and each gripping tool is attached to a different measurement sample mounting portion.
(3) The measurement method according to (1) or (2), wherein the thin structure is a contact lens.
(4) The measurement method according to any one of (1) to (3), wherein the mechanical strength is tensile strength.
(5) A gripping tool used in the measurement method according to any one of (1) to (4) above, comprising a first substrate on which a first support member made of an elastic material is formed, and an elastic material And a second substrate on which a second support member is formed, wherein the first support member has a convex curved surface that at least partially supports the curved surface of the thin structure. .
(6) The gripping tool according to (5), wherein the first support member includes a part of a spherical surface as the convex curved surface.
(7) The gripping tool according to (5) or (6), wherein the first support member is configured to include a structure in which a hemispherical dome is cut along a plane perpendicular to the bottom surface thereof.
(8) The first substrate and the second substrate are foldably connected via a connecting portion, and the first support member and the second support member face each other in a folded state. The gripping tool according to any one of 5) to (7).
(9) The gripping tool according to any one of (5) to (8), wherein the elastic material is an elastomer or rubber.

  According to the present invention, there is an effect that the mechanical strength of a thin structure having a concave curved surface can be measured with the original shape.

(A) And (b) is the schematic which shows the structure of the fixing tool for temporary chucks (gripping tool) used for the measuring method which concerns on one Embodiment of this invention. (A) And (b) is a figure which shows an example which measures the mechanical strength of a contact lens using the fixing tool for temporary chucks shown in FIG. It is the schematic which shows the structure of the deformation | transformation aspect of the fixing tool for temporary chucks shown in FIG. (A) is a graph which shows the result of having measured the tensile strength of the reference method, (b) is the graph which shows the result of measuring the tensile strength of the soft contact lens by the method according to the present invention, respectively. . It is sectional drawing which shows schematic structure of a soft contact lens.

[Embodiment 1]
Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2.

(Fixing tool for temporary chuck)
The temporary chuck fixture (gripping tool) 31 used in the method of measuring the mechanical strength of the thin structure includes a mounting side spacer substrate (first substrate) 31b on which the thin structure is mounted, and a counter electrode side spacer substrate (second substrate). Substrate) 31a as a set. 1A is a plan view of the temporary chuck fixture 31 as viewed from above, and FIG. 1B is a side view of the mounting side spacer substrate 31b as viewed from the side. .

  The mounting side spacer substrate 31b has a support member (first support member) 21 made of an elastic material and a buffer member 23 made of an elastic material on the upper surface of a flat metal substrate 22 having a rectangular upper surface and lower surface. It is a formed structure.

  The support member 21 is formed at a substantially central portion in the longitudinal direction of the upper surface of the metal substrate 22. The support member 21 includes a protruding portion 21b having a convex curved surface and a flat portion 21a formed as a flat film surrounding the protruding portion 21b.

  The convex curved surface (convex surface) of the protrusion 21b has a shape that abuts on a partial region of the concave curved surface (concave surface) of the thin structure (soft contact lens 51 shown in FIG. 2) to be measured. Is formed. More specifically, the convex curved surface of the protrusion 21b has a shape that matches the curvature of the concave curved surface of the thin structure. Thereby, when the soft contact lens 51 is mounted on the support member 21, the convex curved surface supports a partial region of the concave curved surface (side surface on the side of the eyeball) of the soft contact lens.

  When measuring the mechanical strength of the soft contact lens 51, the convex curved surface of the protrusion 21b is, for example, a shape obtained by cutting off a part of the spherical surface as shown in FIG. Here, the spherical surface broadly refers to the outer surface of a sphere, and is used in a concept including, for example, the outer surface of a substantially spherical shape, the outer surface of a substantially oblate ball, and the like. In the case shown in FIG. 1, the protrusion 21b more specifically has a shape obtained by cutting a hemispherical dome (here, a dome obtained by cutting a sphere in one plane intersecting the sphere) by a plane perpendicular to the bottom surface. (Here, the dome is substantially evenly divided in a plane perpendicular to the one plane intersecting the sphere). Then, the protruding portion 21 b is disposed so that the cut surface of the hemispherical dome is along one of the long sides of the upper surface of the metal substrate 22.

  The shape and size of the protrusion 21b may be appropriately determined according to the concave curved surface of the thin structure to be measured. When the thin structure is the soft contact lens 51, the height of the protrusion 21b is, for example, in the range of 0.5 mm or more and 3 mm or less, and the radius of the semicircular bottom surface of the protrusion 21b is, for example, It is in the range of 5 mm or more and 10 mm or less.

  When viewed from the upper surface side of the metal substrate 22, the flat surface portion 21 a is formed in a semicircular shape that extends concentrically with the projecting portion 21 b with the center of the projecting portion 21 b appearing in a semicircular shape as a base point. In addition, since the plane part 21a should just support the outer edge part of the soft contact lens 51, the shape is not specifically limited to a semicircle shape. Further, the thickness of the flat surface portion 21a is not particularly limited as long as there is a thickness that can be supported without damaging the outer edge portion of the soft contact lens 51. For example, the thickness is preferably in the range of 0.5 mm to 2 mm. .

  As shown in FIG. 1B, the planar portion 21a and the protruding portion 21b are preferably formed integrally with the same elastic material, but are formed separately using the same or different elastic materials. Also good.

  The buffer member 23 is a flat film formed on one end side in the longitudinal direction of the upper surface of the metal substrate 22. The buffer member 23 contacts the buffer member 13 described later when the temporary chuck fixture 31 is holding the soft contact lens 51.

  The counter electrode side spacer substrate 31a has a support member (second support member) 11 made of an elastic material and a buffer member 13 made of an elastic material on the upper surface of a flat metal substrate 12 having a rectangular upper surface and lower surface. It is a formed structure. The metal substrate 12 is substantially the same metal substrate as the metal substrate 22.

  The support member 11 is formed as a flat film at a substantially central portion in the longitudinal direction of the upper surface of the metal substrate 12. That is, the position of the support member 11 on the metal substrate 12 and the position of the support member 21 on the metal substrate 22 are in a mutually corresponding relationship. Therefore, when the temporary chuck fixture 31 holds the soft contact lens 51, the soft contact lens 51 is sandwiched between the support member 11 and the support member 21 (particularly the protrusion 21 b).

  The buffer member 13 is a flat film formed on one end side in the longitudinal direction of the upper surface of the metal substrate 12. The position of the buffer member 13 on the metal substrate 12 and the position of the buffer member 23 on the metal substrate 22 are in a mutually corresponding relationship. Therefore, when the temporary chuck fixture 31 holds the soft contact lens 51, the buffer member 13 contacts the buffer member 23.

  In addition, the elastic material which comprises the supporting members 11 * 21 and the buffer members 13 * 23 is an elastomer or rubber | gum, for example. The type of elastomer or rubber is not particularly limited, and examples thereof include silicone rubber, butyl rubber, and ethylene / propylene rubber.

  Moreover, the method of attaching the support members 11 and 21 and the buffer members 13 and 23 to the metal substrates 12 and 22 is not particularly limited, and for example, the support members 11 and 21 and the buffer members 13 and 23 are attached using a double-sided tape or an adhesive.

(Measuring method of mechanical strength)
Next, based on FIG.1 and FIG.2, the measuring method of the mechanical strength using the fixing tool 31 for temporary chucks is demonstrated. 2A is a plan view of an example of the arrangement of the temporary chuck fixtures 31 as viewed from above, and FIG. 2B is a diagram for fixing the temporary chuck to the mechanical strength measuring device. It is the top view which looked at a mode that the tool 31 is attached from the upper direction.

  Here, two temporary chuck fixtures 31 and 31 are used for gripping the soft contact lens 51 as a thin structure.

  First, as shown in FIG. 2A, the two mounting-side spacer substrates 31b and 31b are arranged on a planar stage (not shown) at a predetermined interval. At this time, a spacer (not shown) is bitten between the mounting side spacer substrates 31b and 31b as necessary. The spacing between the mounting side spacer substrates 31b and 31b is not particularly limited. However, in the case of a soft contact lens, for example, it is within a range of 3 mm or more and 10 mm or less, and the length of the thin structure to be measured for mechanical strength. It is preferable that 10% or more and less than 10% are sandwiched.

  The arrangement of the two mounting side spacer substrates 31b and 31b is such that the projections 21b and 21b are close to each other (opposed), and the mounting side spacer substrates 31b and 31b are between the substrates 31b and 31b along the longitudinal direction thereof. The arrangement is such that the line extending symmetrically with respect to the line is a reference.

  Next, the soft contact lens 51 is disposed with its concave curved surface down so as to straddle the two adjacent projecting portions 21b and 21b.

  Next, the counter electrode side spacer substrate 31a is disposed on each mounting side spacer substrate 31b so that the buffer members 13, 23 and the support members 11, 21 face each other (see (b) in FIG. 2). ).

  Next, if necessary, the positional relationship between the temporary chuck fixtures 31 and 31 using clips 71 and 71 etc. that sandwich the end portions of the counter electrode side spacer substrates 31a and 31a and the mounting side spacer substrates 31b and 31b. To fix. At this time, the outer edge portion of the soft contact lens 51 is supported by the flat portions 21a and 21a, and the curved surface portion is supported so as to be sandwiched between the protruding portions 21b and 21b and the support members 11 and 11. Although the buffer members 13 and 23 are not essential, the load applied to the soft contact lens 51 is further reduced when the buffer members 13 and 23 are fixed by the clip 71 or the chuck 61 described later.

  Next, the temporary chuck fixtures 31 and 31 are attached to the mechanical strength measuring device while the positional relationship between the temporary chuck fixtures 31 and 31 is fixed. Specifically, as shown in FIG. 2B, the temporary chuck fixtures 31 and 31 fixed by the clips 71 and 71 are attached between the chucks 61 and 61 arranged opposite to each other. .

  The chuck 61 corresponds to a measurement sample mounting portion of a mechanical strength measurement device. Each chuck 61 is composed of, for example, a pair of metal flat plates, and the temporary chuck fixture 31 is sandwiched between the flat plates. Each chuck 61 grips the temporary chuck fixture 31 at the central portion of the long side on the side where the protrusion 21b is not disposed. That is, when viewed from above, the chucks 61 and 61 are arranged at positions facing each other with the soft contact lens 51 interposed therebetween.

  When the attachment to the chucks 61 and 61 is completed, the used clips 71 and 71 are removed as necessary.

  The mechanical strength of the soft contact lens 51 can be measured by moving the mechanical strength measuring device in accordance with its operation manual. For example, when measuring the tensile strength as the mechanical strength, the chucks 61 and 61 are moved in a direction away from each other at a predetermined speed. When measuring the bending strength, the chuck 61 is slightly rotated with the long side of the temporary chuck fixture 31 that holds the soft contact lens 51 as the axis of rotation.

  A soft contact lens is preferable as the thin structure to be measured for mechanical strength, but is not particularly limited thereto. Other examples of the thin structure include a hard contact lens, an intraocular lens, a catheter, and an artificial blood vessel. The material of the thin structure is preferably a plastic, rubber, glass or the like. Moreover, although the thickness of a thin structure is not specifically limited, For example, it is 1 mm or less, it is preferable that it is 0.5 mm or less, and it is more preferable that it is 0.25 mm or less.

  Also, the type of mechanical strength to be measured is not particularly limited to tensile strength and bending strength.

[Embodiment 2]
Hereinafter, a modified form of the first embodiment will be described in detail with reference to FIG. The same members as those described in the first embodiment are given the same member numbers, and detailed descriptions thereof are omitted.

  The temporary chuck fixture 31 ′ according to the present embodiment has a configuration in which a mounting side spacer substrate 31 b and a counter electrode side spacer substrate 31 a are foldably connected via two hinges (connecting portions) 41 and 41. It is. In this example, the hinges 41 and 41 connect the long side of the mounting side spacer substrate 31b where the protrusion 21b is not formed and the long side of the counter electrode side spacer substrate 31a.

  In the temporary chuck fixture 31 ′, when the mounting side spacer substrate 31 b and the counter electrode side spacer substrate 31 a are folded, the support members 11 and 21 face each other and the soft contact lens 51 can be held therebetween.

  The short side of the mounting side spacer substrate 31b and the short side of the counter electrode side spacer substrate 31a may be foldably connected by a connecting portion such as a hinge. Moreover, as a connection part, it replaces with a hinge and may connect both board | substrates with a flexible film, and may connect both board | substrates so that it can be bent with the thin part formed with the same material as the metal substrates 12 * 22.

  Hereinafter, based on an Example, this invention is demonstrated more concretely.

  In this embodiment, two temporary chuck fixtures 31 and 31 shown in FIGS. 1 and 2 are used, and the soft contact lens 51 is held as shown in FIG. went.

  As the soft contact lens 51, a commercially available product (Calaview, manufactured by Innova Vision) was used. In addition, the convex curved surface of the protruding portion 21b was formed in a shape and size matched to the curvature of the concave curved surface (particularly the peripheral portion of the back side surface) of the soft contact lens 51. The approximate size of the protrusion 21b was about 1 mm in height and about 7 mm in the radius of the semicircular bottom surface. The support members 11 and 21 were both made of silicone rubber.

  At the time of measurement, the soft contact lens 51 is taken out of the storage solution in the storage container, and the attached storage solution is removed. Then, as shown in FIG. And attached to chucks 61 and 61 of a tensile tester (manufactured by Shimadzu Corporation, EZGraph). The distance between the temporary chuck fixtures 31 before starting the tension (distance between chucks) was 5 mm.

  And about 2 minutes after removing the adhering preservation solution, the tensile strength was measured by pulling the chucks 61 and 61 at a tensile speed of 10 mm / min. The test was performed three times (n = 1, 2, 3).

  As a reference experiment, the tensile strength of the strip-shaped test piece cut out from the soft contact lens 51 (Calaview, manufactured by Innova Vision) was measured. The strip-shaped test piece has a width of about 5 mm including the central portion of the soft contact lens (the length of the long side of the square box) and corresponds to the diameter of the lens, as shown by a square box in the cross-sectional view of FIG. Length.

  In the reference experiment, as the temporary chuck fixture, two counter electrode spacer substrates 31a shown in FIG. 1 were used, and the test piece was gripped by the planar silicone rubber support members 11 and 11. I tried to do it. Except for this point, the test piece was attached to the chucks 61 and 61 via the temporary chuck fixture in the same manner as in Example 1, and the tensile strength was increased by pulling the chucks 61 and 61 at a tensile speed of 10 mm / min. Measurements were made. The test was performed three times (n = 1, 2, 3).

  The results obtained in the examples and reference experiments are shown in Table 1 and FIG. 4A shows the measurement results obtained in the reference experiment, and FIG. 4B shows the measurement results obtained in the examples.

  As shown in FIG. 4, in both the reference experiment and the example, no yield point or the like was found, and the measurement object showed a behavior of breaking at a stretch after showing a certain elongation. That is, it was confirmed that only the tensile fracture strength was obtained as the material property in the examples as in the case of the reference experiment.

  In addition, regarding CV, which is an index of reproducibility, the value of the example was lower than that of the reference experiment, indicating better reproducibility (Table 1).

  From the above results, it was shown that the method of the example can be used as a measurement method of tensile fracture strength excellent in reproducibility.

  In addition, when the result of a reference experiment is compared with the result of an Example, the direction of an Example has large tensile fracture strength. The reason is considered that the tensile stress is most applied to the thickest bevel portion (indicated by a circle in FIG. 5) in the method of the embodiment. That is, the method of the embodiment can measure the strength including the bevel portion peculiar to the product shape of the soft contact lens, and thus can be a test method particularly useful for product evaluation of the soft contact lens.

  The present invention can be used for measuring the mechanical strength of a thin structure having a concave curved surface.

11 Support member (second support member)
21 Support member (first support member)
21a Plane portion (first support member)
21b Protrusion (first support member)
31 Temporary chuck fixture (gripping tool)
31 'Temporary chuck fixture (gripping tool)
31a Counter electrode spacer substrate (second substrate)
31b Mounting side spacer substrate (first substrate)
41 Hinge (connecting part)
51 Soft contact lens (thin structure)
61 Chuck (Measurement sample mounting part)

Claims (9)

A method for measuring the mechanical strength of a thin structure having a concave curved surface,
Using a gripping tool including a first support member made of an elastic material and a second support member made of an elastic material, the first support member surface-supports at least a part of the curved surface of the thin structure, The thin structure is sandwiched between the first support member and the second support member,
A mechanical strength measurement method for measuring the mechanical strength of a thin structure by attaching the gripping tool sandwiching the thin structure to a measurement sample mounting portion of a mechanical strength measuring device.   The measurement method according to claim 1, wherein the thin structure is sandwiched at two locations using the two gripping tools, and each gripping tool is attached to a different measurement sample mounting portion.   The measurement method according to claim 1, wherein the thin structure is a contact lens.   The measuring method according to claim 1, wherein the mechanical strength is tensile strength. A gripping tool used for the measurement method according to any one of claims 1 to 4,
A first substrate on which a first support member made of an elastic material is formed;
A second substrate on which a second support member made of an elastic material is formed,
The gripping tool, wherein the first support member has a convex curved surface that at least partially supports the curved surface of the thin structure.   The gripping tool according to claim 5, wherein the first support member includes a part of a spherical surface as the convex curved surface.   The gripping tool according to claim 5 or 6, wherein the first support member is configured to include a structure in which a hemispherical dome is cut along a plane perpendicular to a bottom surface thereof.   The said 1st board | substrate and the 2nd board | substrate are connected so that folding is possible via a connection part, and a 1st support member and a 2nd support member oppose in the folded state. The gripping tool according to any one of 7.   The gripping tool according to any one of claims 5 to 8, wherein the elastic material is an elastomer or rubber.

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