JP3487467B2 - Manufacturing method of glass lens - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the wall thickness of a press-molded body. INDUSTRIAL APPLICABILITY The method for measuring the wall thickness of a molded product of the present invention is particularly suitable for measuring the wall thickness of a precision molded product having high shape accuracy and fine surface roughness that does not require a polishing step after press molding.

[0002]

2. Description of the Related Art In recent years, the precision molding method for glass or plastic moldings, which has been extensively studied, uses a molding die having a shape corresponding to a predetermined shape and having high shape accuracy and fine surface roughness. By press-molding the preform in a predetermined viscosity range, it is possible to obtain a molded product such as a molded product having an optical mirror surface that does not require polishing finishing after the press molding. However, due to the shape of the preform and the deviation of the preform in the mold during molding, elongation (defective elongation in which the peripheral edge of the molded product is not sufficiently expanded) occurs and the prescribed wall thickness cannot be obtained. There is. Furthermore, when molding conditions such as temperature and pressure change and cooling conditions after molding change, the individual molded products have variations in shrinkage during cooling, and the same wall thickness cannot be obtained.

Therefore, it is inspected whether the wall thickness is within a predetermined tolerance.
Usually a micrometer or a caliper is used. In the case of the micrometer, place the molded body on the measuring table on which the micrometer is fixed, and contact the probe of the micrometer from above the molded body to the location where the wall thickness is to be measured. The wall thickness was measured by reading the scale on the gauge. In the case of a caliper, bring the part to be measured of the molded product into contact with one of the calipers, slide the other movable measuring device until it comes into contact with the molded product, and sandwich the molded product. The wall thickness was measured by reading the scale.

[0004]

As described above, the wall thicknesses of the molded bodies vary, and not all the molded bodies fall within the predetermined tolerance. For example, when the molded body is a biconvex microlens having a diameter of 5 mm and a center thickness of 2 mm, the tolerance of the center thickness is 15 μm, which is extremely small. Therefore, it is necessary to inspect the thickness of the molded lenses by cooling them, taking them out of the mold, and then inspecting the thickness of all the lenses using a measuring tool such as a micrometer or a caliper. In order to measure the wall thickness of a molded product using a measuring tool such as a micrometer or calipers, it is necessary to bring the measuring tool into contact with the molded product, which is a factor that causes defects such as scratches on the surface of the molded product. Was there. Furthermore, to measure the center wall thickness of a meniscus lens or a biconcave lens, it is not easy to find the center point first, and it is necessary to center the lens using a jig before measuring. It took a lot of effort and time.

The present invention has been made to solve the above problems, and an object of the present invention is to easily measure the wall thickness of a molded body without contacting the measuring tool with the molded body. It is to provide a method of measuring.

[0006]

The present invention has been made in order to solve these problems, and the method for measuring the wall thickness of a molded product according to the present invention is such that at least one of them is slidably guided by a barrel mold. Then, the wall thickness of the molded body obtained by press-molding the body to be molded by the first mold member and the second mold member that are separated from each other In the method for measuring the wall thickness of a molded body to be measured, a distance a between a preset first reference point of the first mold member and the molding surface of the first mold member, and a second mold member or a barrel mold The distance b between the preset second reference point and the molding surface of the second mold member is measured in advance, and the pressure-molded molded product is used as the first mold member and the second mold member. It is cooled in a state of being sandwiched by and then the distance between the first reference point and the second reference point is measured, and the two previously measured Away a, based on the b, and obtains the thickness of the molded body by calculation. Further, as one aspect of the present invention, when there are a plurality of molds including the first mold member, the second mold member, and the body mold, in each mold, the sum of the two distances a and b. Alternatively, the difference is made constant as a type constant. The preset reference point is the upper end surface of each of the first die member, the second die member and the body die, or in the vicinity thereof, or the bottom surface thereof, and may be any location that does not interfere with the distance measurement. There is no particular limitation.

[0007]

According to the method of measuring the wall thickness of a molded body of the present invention, the height or distance a between the preset first reference point of the first mold member and the molding surface of the first mold member, and the second The height or distance b between the preset second reference point of the mold member or the barrel mold and the molding surface of the second mold member is measured in advance, and the pressure-molded molded body is used as the first molded body. Cooling in a state of being sandwiched between the mold member and the second mold member, and then measuring the distance between the first reference point and the second reference point to obtain the two distances a and b measured in advance. Based on the calculation, the wall thickness of the molded body is obtained, so the wall thickness of the molded body in the mold can be indirectly measured without contacting the measuring tool with the molded body. Since the measuring tool such as the stylus is not brought into contact with the molded article, the surface of the molded article is not scratched. In addition, in the case of lens molding, even a lens such as a meniscus lens or a biconcave lens whose center thickness is extremely difficult to measure is measured by measuring the distance between the first reference point and the second reference point of the mold. Since the thickness of the body is obtained, the thickness can be easily and accurately measured regardless of the shape of the lens in the mold. Further, when there are a plurality of molds including the first mold member, the second mold member and the body mold, in each mold, the sum or difference of the two distances a and b is used as a mold constant. By making it constant, the wall thickness of the molded body can be continuously obtained from the measurement of only the distance between the first reference point and the second reference point, and the obtained wall thickness information can be immediately transmitted to the previous step. You can give feedback.

[0008]

Embodiments of the present invention will be described in detail below with reference to the drawings. [Embodiment 1] FIG. 1 is a schematic cross-sectional view of a molding die in a state before lens molding, and FIG. 2 shows a molding die in which a molded convex lens is housed in a mold and a thickness measuring device for a molding. It is a schematic sectional drawing shown. The molding die is composed of a die member 1, a die member 2 and a cylindrical body die, and the die member 1 and the die member 2 are housed in the body die. Each mold member contraction coefficient 55 × 10 _- ⁷ /
C. Tungsten carbide was used. A protrusion 8 is provided at the center of the upper surface of the mold member 1, and the uppermost end face of the protrusion 8 receives the pressure of the plunger 12 during molding.
Under the pressure, the mold member 1 descends along the inner surface of the barrel mold until the preform 9 is plastically deformed to fill the cavity. The previously spherical processed heavy barium crown optical glass contraction coefficient 79 × 10 in the molded _- using ⁷ / ° C. preform 9. The weight of the preform 9 is 2.7 g. Prior to molding, from the height (a) from the uppermost end surface (first reference point) of the projection 8 of the mold member 1 to the center of the molding surface and the upper end surface 5 (second reference point) of the barrel mold in advance. Mold member 2
The height (b) to the center of the molding surface was measured. a is 1
It was 8.600 mm and b was 21,000 mm. The value of b may be calculated by using the values obtained by measuring the heights of the barrel die, the die member 2, and the flange portion of the die member 2. First, a molding die in which the preform 9 is housed between the mold members 1 and 2 is placed in a press molding device (not shown), heated at 620 ° C., and then pressurized to have a diameter of 19.00 mm.
The biconvex lens 4 was molded. The mold member 1 descends in the barrel mold following the contraction of the molded body due to cooling after molding, but in order to prevent the lowering of the mold member 1 from being obstructed, a stepped portion 11 is provided inside the barrel mold. Since the depth is provided with a margin with respect to the amount of shrinkage of the molded body, the molded body is in contact with the mold member 1 and the mold member 2 and is kept clamped. Then, the mold was taken out from the press molding apparatus and cooled to room temperature. After cooling, the pressure-molded lens 4 is sandwiched between the mold member 1 and the mold member 2 on the base 13 in which the thickness measuring device for the molded body is arranged above the base 13. Placed the mold.

First, the air cylinder 17 for raising and lowering the wall thickness measuring device is operated to move the piston rod 18 and the connecting member 1.
The lower end of the reference positioning ring 14 was lowered via 9 until it abuts on the upper end surface 5 of the barrel die. First, the tip of the contactor 16 contacts the tip of the projection 8 provided on the upper end of the mold member 1, that is, the uppermost end face of the mold member 1, and then the lower end of the reference positioning ring 14 contacts the upper end face 5 of the barrel mold. Contact. At this time, the contactor 16 is pressed downward by the spring built in the contact type displacement sensor 15 to maintain the contact state.
The contact displacement sensor 15 is fixed to the reference positioning ring 14. The difference (L) between the height of the upper end surface 5 of the barrel die and the height of the uppermost end surface of the die member 1 is obtained by contacting the uppermost end surface of the die member 1 with the height information of the contactor 16 pushed upward. It is given to the displacement sensor 15 and measured. The measured value obtained was 3.010 mm. In this case, the upper end surface 5 of the barrel die is used as the second reference point, and the height L of the uppermost end surface of the die member 1 from the reference point, that is, the first reference point L = 3.010 mm is measured.

At this time, the center wall thickness of the lens 4 housed in the molding die is obtained as follows. FIG. 3 is a diagram showing the measurement principle of this embodiment, and the mold structure is simplified for easy understanding. L ₀ = L + (b−a) K = b−a, ∴L ₀ = L + K (1) In the above formula, L ₀ is the center wall thickness of the molded body to be obtained, and L is on the mold member 1. End face 6 (first reference point) and upper end face 5 of the barrel
The height difference from the (second reference point), a is the height from the upper end surface 6 (first reference point) of the mold member 1 to the molding surface thereof, and b is the upper end surface 5 of the barrel die (second reference point). From the reference point of 1) to the molding surface of the mold member 2. K is a mold constant determined by the height of each mold forming the mold, and is obtained by measuring the heights of the mold member 1, the mold member 2 and the body mold in advance,
The value was 2.400 mm from the previously measured values of a and b. Therefore, the center wall thickness (L ₀ ) of the lens 4 is the difference (L) 3. between the heights of the upper end surface 5 of the barrel die and the uppermost end surface of the die member 1 obtained by measurement from the above equation (1). By adding a mold constant (K) of 2.400 mm to 010 mm, a center wall thickness (L ₀ ) of the molded body or lens of 5.410 mm is obtained. The molded body is taken out by disassembling the molding die after measuring the wall thickness.
In this way, the center wall thickness of the molded body housed in the mold is indirectly determined, and since the measuring tool is not brought into contact with the molded body, the lens surface is not scratched, and it is easy and The central thickness of the lens could be accurately determined.
Although the tip of the protrusion 8 is measured as the upper end surface of the mold member 1 in the present embodiment, the flat portion 6 around the protrusion 8 may be measured as the upper end surface of the mold member 1.

[Embodiment 2] This embodiment will be described with reference to FIG. FIG. 4 is a schematic cross-sectional view showing a wall thickness measuring device for a molding die and a molded body. The forming die used in this embodiment has basically the same structure as that of the forming die of Embodiment 1 except that the upper end surface 6 of the die member 1 is a flat surface. Prior to molding,
The height (a) from the upper end surface 6 (first reference point) of the mold member 1 to the center of the molding surface and the center of the molding surface of the mold member 2 from the upper end surface 5 (second reference point) of the barrel mold The height (b) was measured. First, a molding die containing a preform between the mold members 1 and 2 was placed in a press molding device (not shown), and after heating, pressure was applied to mold the convex lens 4. The pressurization is performed by a plunger having a flat surface having a diameter larger than the upper end diameter of the mold member 1 at its lower end, and
The process was repeated until the flat surface at the lower end of the plunger came into contact. The volume of the preform used was set so as not to exceed the volume of the cavity of the molding die. Therefore, the upper end surface 5 of the barrel die and the upper end surface 6 of the die member 1 are brought to the same level by the pressure, and the pressing is completed. Then, the mold was taken out from the press molding apparatus and cooled. The cooled compact undergoes volumetric shrinkage matching its own coefficient of shrinkage. In this example, silicon carbide having a shrinkage coefficient of 42 × 10 ⁻⁷ / ° C. was used for each mold member, and a glass preform having a shrinkage coefficient of 79 × 10 ⁻⁷ / ° C. was used for the molding target. Therefore, due to the shrinkage of the cooled molded body, the shrinkage coefficient of the molded body is larger than that of the molding die. Therefore, the upper end surface 6 of the mold member 1 located immediately after the pressure molding and the mold member after cooling are molded. There is a height difference (L) from the position of the upper end surface 6 of 1. At the set measurement temperature of 30 ° C., the lens 4 was placed on the base 13 with the lens 4 housed in the mold.

The thickness measuring device for a molded body used in this embodiment is a contactor 1 provided at the lower end of a contact type displacement sensor 15.
The contact type displacement sensor 15 is the same as that of the first embodiment except that the lower end of 6 has a curved surface. First, the air cylinder 17 of the elevating device was operated, and the lower end of the reference positioning ring 14 was lowered via the piston rod 18 and the connecting member 19 until it abuts the upper end surface 5 of the barrel die. At this time, the tip of the contactor 16 provided at the lower end of the contact displacement sensor 15 is
It is located below the level of the lower end surface of the reference positioning ring 14. First, the tip of the contactor 16 contacts the upper end surface 6 of the die member 1, and then the lower end of the reference positioning ring 14 contacts the upper end surface 5 of the barrel die. At this time, the contactor 16 is pressed downward by the spring built in the contact type displacement sensor 15 to maintain the contact state. The difference (L) between the height of the upper end surface 6 of the mold member 1 and the height of the upper end surface 5 of the body mold is
The height information of the contact 16 which is brought into contact with the upper end surface 6 of the mold member 1 and pushed back upward is given to the contact displacement sensor 15.
To be measured. In this case, the height (L) of the upper end surface 6 of the die member 1 from the reference point, that is, the first reference point (L) is measured with the upper end surface 5 of the barrel die as the second reference point.

At this time, the convex lens 4 housed in the molding die
The center wall thickness of is determined as follows. FIG. 5 is a diagram showing the measurement principle of this embodiment. If L ₀ = (b−a) −L K = b−a is set, ∴L ₀ = K−L (2) The central wall thickness (L ₀ ) of the convex lens 4 is obtained by measuring in advance from the above formula. The mold constant (K) is obtained from the values of a and b, and from the mold constant (K), the upper end surface 6 of the mold member 1 and the upper surface of the body mold obtained by measuring with the lens housed in the mold are obtained. It is obtained by subtracting the height difference from the end surface 5, that is, the height difference (L) between the first reference point and the second reference point. The molded body is taken out by disassembling the molding die after measuring the wall thickness. In this way, the center wall thickness of the molded body can be easily obtained by indirect measurement without bringing the measuring tool into contact with the molded body. In addition, since the measuring tool is not brought into contact with the molded body, the surface of the molded body is not scratched.

[Embodiment 3] FIG. 6 is a view showing a state of measuring the wall thickness of the meniscus lens housed in the molding die of this embodiment. The molding die is composed of a mold member 1, a mold member 2 and a body mold. Since the meniscus lens is molded, the mold member 1
The molding surface of is a convex surface, and the molding surface of the mold member 2 is a concave surface. In the state of the molding die after lens molding, the upper end surface 6 of the mold member 1 is higher than the upper end surface 5 of the barrel die. 23, 24
Is a light reflection type laser sensor mounted on a mounting member 25 arranged above the mold member 1. Prior to molding
In advance, the height (a) from the upper end surface 6 (first reference point) of the mold member 1 to the center of the molding surface and the flange part upper end surface 7 (second reference point) of the mold member 2 from the molding surface The height (b) to the center of was measured. After molding the lens, the molding die is cooled to room temperature, and then the molding die in a state where the pressure-molded lens 4 is sandwiched between the molding member 1 and the molding member 2 is the base 13
Placed on top. First, the height of the upper end surface 6 (first reference point) of the mold member 1 is measured by the laser light 27 emitted from the light reflection type laser sensor 24, and then the laser light 26 from the light reflection type laser sensor 23 is measured. Was emitted to measure the height of the flange portion upper end surface 7 (second reference point) of the mold member 2. From the difference between the two measured values, the difference between the height of the upper end surface 6 of the mold member 1 and the height of the flange portion upper end surface 7 of the mold member 2, that is, the difference in height between the first reference point and the second reference point ( L) was determined.

At this time, the central wall thickness of the meniscus lens 4 housed in the molding die is obtained as follows. L ₀ = L− (a + b) K = a + b ∴L ₀ = L−K (3) The center wall thickness (L ₀ ) of the meniscus lens 4 is the above (3).
From the formula, from the height difference (L) between the first reference point and the second reference point obtained by measuring with the lens housed in the molding die,
The center thickness of the meniscus lens housed in the mold was indirectly determined by subtracting the mold constant (K) obtained by measuring a and b in advance. The molded body is taken out by disassembling the molding die after measuring the wall thickness. In this way, the center wall thickness of the molded body housed in the molding die is indirectly determined, and the measuring tool is not brought into contact with the molded body, so that the lens surface is not scratched. Even in the case of a meniscus lens whose shape is difficult to measure the center thickness, the center thickness of the lens could be easily and accurately determined. The light reflection type laser sensor 2
The height difference (L) can be automatically obtained by introducing and processing the detection signals of 3 and 24 into a computer.

[Embodiment 4] FIG. 7 is a diagram showing a state of measuring the wall thickness of a concave lens housed in the molding die of this embodiment. The number of light reflection type laser sensors for measurement used in this embodiment is one. The mold is a mold member 1 and a mold member 2.
Also, the molding surfaces of the mold member 1 and the mold member 2 are both convex, because they are formed of a barrel mold and mold a concave lens. Prior to molding, the upper end surface 6 of the mold member 1 (first reference point) is previously formed.
To the center of the molding surface (a) and the height from the bottom surface (second reference point) of the mold member 2 to the center of the molding surface (b) were measured. The substrate surface of the substrate 20 on which the mold member 2 is placed may be adopted as the second reference point. After the lens was molded, the mold was taken out from the press molding device and cooled to room temperature. After cooling, the molding die in which the concave lens 4 was housed was placed on the substrate 20 having a horizontal and smooth surface.
Next, laser light 26 was emitted from the light reflection type laser sensor 23, and the distance from the sensor 23 to the upper end surface 6 of the mold member 1 was measured. From this distance and the distance from the sensor 23 to the substrate 20 obtained by measurement in advance, the mold member 1 from the substrate 20 is obtained.
The height (L) from the bottom surface of the mold member 2 to the upper end surface 6 of the mold member 1 was obtained.

At this time, the concave lens 4 housed in the molding die 4
The center wall thickness of is determined as follows. If L ₀ = L- (a + b) K = a + b, then ∴L ₀ = L−K (4) The central thickness (L ₀ ) of the concave lens 4 can be calculated from the equation (4) above.
The mold constant (K) obtained by measuring a and b in advance from the height (L) of the bottom surface (second reference point) of the mold member 2 from the upper end surface 6 (first reference point) of the mold member 1. ), The center wall thickness of the concave lens housed in the mold was determined. After measuring the wall thickness, the lens is taken out by disassembling the molding die. In this way, the center wall thickness of the molded body housed in the molding die is indirectly determined, and the measuring tool is not brought into contact with the molded body, so that the lens surface is not scratched. Even with a concave lens whose shape is difficult to measure the center thickness, the center thickness of the lens could be easily and accurately determined.

[Embodiment 5] FIG. 8 is a view showing a state of measuring the wall thickness of a concave lens housed in the molding die of this embodiment. Prior to molding, the height (a) from the upper end surface 6 (first reference point) of the mold member 1 to the center of the molding surface and the upper end surface 5 (second reference point) of the barrel mold 3 are used to form the mold. The height (b) to the center of the molding surface of the member 2 was measured. After the lens was molded, the mold was cooled to room temperature, and then the mold containing the lens molded therein was placed on the base 13. The light reflection type laser sensor 28 used in the present embodiment is attached to a support 29 and is movable left and right by a cylinder 17 of a moving device via a piston rod 18. First,
The height of the upper end surface 6 (first reference point) of the mold member 1 and the height of the upper end surface 5 (second reference point) of the body shape are alternately measured by moving the light reflection type laser sensor 28 left and right. Then, the measurement signals are sequentially guided to a computer (not shown) and processed to increase the height between the upper end surface 6 (first reference point) of the mold member 1 and the upper end surface 5 (second reference point) of the barrel mold. The difference (L) was calculated. The center wall thickness of the lens housed in the molding die is the height of the first reference point and the second reference point from the mold constant (K = ba) obtained from a and b measured in advance. It was determined by subtracting the difference (L). The molded body is taken out by disassembling the molding die after measuring the wall thickness. In this way, the center wall thickness of the molded body housed in the molding die is indirectly determined, and the measuring tool is not brought into contact with the molded body, so that the lens surface is not scratched. Even with a concave lens whose shape is difficult to measure the center thickness, the center thickness of the lens could be easily and accurately determined.

[Embodiment 6] In this embodiment, the same three molding dies as those of the above-mentioned Embodiment 2, which are composed of the mold member 1, the mold member 2 and the cylindrical body mold, were used (see FIGS. 4 and 5). 3 prior to molding
The height of each mold member of the individual molding dies A, B, and C was measured. Further, with the upper end surface 6 of the mold member 1 as the first reference point, the height (distance a) from the reference point to the center of the molding surface of the mold member 1 and the upper end surface 5 of the barrel mold as the second reference point. As a point, the height (distance b) from the reference point to the center of the molding surface of the mold member 2 was measured. At this time, the type constant K becomes ba. The mold used in this example has a mold constant K of 5.4 with respect to variations in dimensional values of individual mold members in each mold.
The height of the flange portion of the mold member 2 was adjusted and processed so as to have a constant value of 00 mm. As a result, the mold constants K of the molding dies A, B, and C were 5.400 mm and 5.403 m, respectively.
m, 5.398 mm, both are within the tolerance range and can be said to be constant. Table 1 shows the measured height values, a and b values, and mold constants K of the mold members A, B, and C.

[0020]

[Table 1] (Unit: mm)

Using these molding dies, the biconvex lens 4 having a diameter of 19.00 mm was molded in the same manner as in Example 2. The preform used is a heavy barium crown optical glass processed into a spherical shape having a weight of 2.7 g. After cooling, using the same measuring device as in Example 2, the first
The difference (L) in height between the reference point of 1 and the second reference point was measured. The molding dies A, B, and C were 0.015 mm, 0.017 mm, and 0.014 mm, respectively. The center thickness of the lens was determined from these measured values and the type constant K by a controller (not shown) connected to the measuring device. The center wall thickness (L ₀ ) of the lens is obtained by KL. The center thickness (L ₀ ) of the obtained lens was 5.385 mm for the molds A, B, and C, respectively.
It was 5.386 mm and 5.384 mm. Further, the wall thickness of the molded body was continuously measured by synchronizing the control device with the press machine, and the measured thickness variation information was fed back to control the molding conditions such as the volume of the preform and the press pressure. In this embodiment, since a plurality of molding dies were used and their mold constants were made constant, the wall thickness of the molded body was continuously measured by measuring only the height (distance) of the first reference point and the second reference point. It became possible to immediately feed back the lens thickness variation information to the previous process.

The shape and size of the lower end of the plunger are preferably set so that the pressing is completed when the plunger for pressurizing contacts the first reference point and the second reference point. By setting in this way, even if the preform has some capacity fluctuation, the thickness is almost constant,
A good lens can be obtained. Thus, when using a plurality of molding dies, it is effective to make the mold constant K of each mold constant, and moreover, it is easy to detect when the thickness abnormality of the lens occurs. The wall thickness measuring methods shown in Examples 2, 5 and 6 above are the distances from the upper end surface 5 (second reference point) of the barrel die to the upper end surface 6 (first reference point) of the die member 1, that is, Since only the amount of shrinkage after pressing is measured, the absolute value of measurement is smaller than in the other examples, and more accurate measurement can be performed. The present invention is not limited to the above-mentioned examples, and it is not necessary to measure the wall thickness by cooling the molding die to room temperature,
If the temperature is below, the amount of shrinkage to room temperature is small and it can be grasped accurately, so there is no problem. The configuration and shape of the molding die has a structure in which the molding is held in contact with the molding surfaces of the mold member 1 and the mold member 2 even after cooling after molding the molded body. The structure is not particularly limited as long as the height of the measurement target portion of each mold member can be measured.
Furthermore, in Example 1, the difference in height of the uppermost end surface of the mold member 1 from the reference surface was measured with the upper end surface 5 of the barrel mold as the reference surface. As the reference surface, the difference in height of the upper end surface 5 of the barrel mold from the reference surface may be measured. When measuring the wall thickness, the measurement location of the height of each mold member is not limited to its uppermost end face, and for example, in the case of a barrel mold, a cut is provided on the flat upper end face or around the upper end of the barrel mold. In this case, the bottom surface of the cut portion may be used as the measurement reference point. Measuring tools when measuring the wall thickness, in addition to the contact type displacement sensor and the light reflection type laser sensor shown in each of the above examples,
Other optical reading measuring tools, micrometers, etc. may be used, or a dial gauge having a contact point at the tip may be fixed to a column for use. Further, as the elevating device and the moving device for operating the contact displacement sensor, the light reflection type laser sensor and the like, a device for mechanically driving can be used other than the cylinder used in the above-mentioned embodiment.
As for the reference positioning member, in addition to the ring-shaped member shown in FIGS. 2 and 4, the lower ring-shaped portion of the reference positioning member may be used by providing a plurality of pins having the same height level on the lower end surface. . In this case, the pins are preferably arranged at equal intervals. Alternatively, the structure may be such that it comes into contact with only one predetermined position on the upper end surface 5 of the body mold. The method for measuring the wall thickness of a molded body of the present invention can be applied not only to lenses but also to other molded bodies, and examples of the material of the molded body include glass and resin.

[0023]

As described above in detail, in the method for measuring the wall thickness of a molded article of the present invention, the two distances a and b of the mold are measured in advance before molding, and after molding and cooling, the molding die is molded. In a state in which the molded body that is molded therein is housed, the distance between the preset first reference point and the second reference point of the mold member that forms the molding die is measured, and the two distances a and b are measured. Based on the above, the thickness of the molded body is calculated by the calculation, so that the central wall thickness of the molded body housed in the molding die can be indirectly measured. Since the measuring tool such as the stylus is not brought into contact with the molded article, the surface of the molded article is not scratched. Furthermore, in the case of lens molding, it is extremely difficult to find the center point of the wall thickness measurement of a meniscus lens or a biconcave lens, and it takes a long time to measure the center of wall thickness of such a lens. The method for measuring the wall thickness of a molded article according to the present invention is
Since the wall thickness of the molded body is obtained by measuring the distance between the reference point and the second reference point, the wall thickness can be measured easily and in a short time regardless of the shape of the molded body. Further, when molding is performed using a plurality of molding dies, the above-mentioned 2 of each molding die is used.
By making the sum or difference of the two distances a and b constant as a type constant, the wall thickness of the molded body can be continuously known by measuring only the distance between the first reference point and the second reference point. ,
The obtained thickness information can be promptly fed back to the previous process.

[0024]

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a molding die showing a state immediately before molding of a molded body in Example 1 of the present invention.

FIG. 2 is a schematic cross-sectional view of a molding die and a wall thickness measuring device showing a wall thickness measuring method for a molded body according to Example 1 of the present invention.

FIG. 3 is a schematic cross-sectional view showing the principle of the method for measuring the wall thickness of a molded product according to Example 1 of the present invention.

FIG. 4 is a schematic cross-sectional view of a molding die and a wall thickness measuring device showing a wall thickness measuring method for a molded body according to Example 2 of the present invention.

FIG. 5 is a schematic cross-sectional view showing the principle of the method for measuring the wall thickness of a molded body according to Example 2 of the present invention.

FIG. 6 is a schematic cross-sectional view of a molding die and a wall thickness measuring device showing a wall thickness measuring method for a molded body according to Example 3 of the present invention.

FIG. 7 is a schematic cross-sectional view of a forming die and a wall thickness measuring device showing a wall thickness measuring method for a molded body according to Example 4 of the present invention.

FIG. 8 is a schematic cross-sectional view of a forming die and a wall thickness measuring apparatus showing a wall thickness measuring method for a molded body according to Example 5 of the present invention.

[Explanation of symbols]

1 mold member 1 2 mold member 2 3 barrel mold 4 molded body 5 upper end surface of barrel mold 6 upper end surface of mold member 1 mold member 2 upper end surface of flange portion a first reference point of the molded member 1 and its molding surface Distance b between the second reference point and the molding surface of the mold member 2 center thickness L _{0 of the} molded body distance between the first reference point and the second reference point

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B29C 49/00-51/46 B30B 15/10-15/28 C03B 7/00-21/06 G01B 5 / 00-5/32 G01B 21/00-21/32

Claims (4)

(57) [Claims] 1. A glass which is guided by a cylinder mold, at least one of which slides away from and approaches one another, and which has a molding surface facing the inside of the cylinder mold and a second mold member A method of manufacturing a glass lens by press-molding a preform, comprising: a distance a between a preset first reference point of a first mold member and a molding surface of the first mold member; The distance b between the preset second reference point of the second mold member or the barrel mold and the molding surface of the second mold member is measured in advance, and the heated glass preform is used as the first mold member. And a second mold member for pressure molding, and the pressure-molded glass lens is cooled while being sandwiched between the first mold member and the second mold member, and then the first reference point and The distance between the second reference points is measured, and the two distances a previously measured,
After obtaining the thickness of the glass lens by calculation based on b, the glass lens is taken out from the first mold member and the second mold member, and the first mold member and the second mold member are obtained. And a plurality of molding dies each including a barrel mold, and in the plurality of molding dies, a sum or a difference between the two distances a and b is made constant as a mold constant, thereby manufacturing a plurality of glass lenses. Method. 2. A molding die containing a glass preform is placed in a molding apparatus, the heated glass preform is pressure-molded, and the pressure-molded glass lens is taken out from the molding apparatus and cooled. The manufacturing method according to claim 1, wherein: 3. The first reference point is the upper end surface of the first mold member,
The manufacturing method according to claim 1, wherein the second reference point is an upper end surface of the barrel mold. 4. A glass by means of a first mold member and a second mold member which are guided by a barrel mold and at least one of which slides away from and comes close to each other and has a molding surface facing each other in the barrel mold. A method of manufacturing a glass lens by press-molding a preform, comprising: a distance a between a preset first reference point of a first mold member and a molding surface of the first mold member; A first mold member containing a glass preform, in which a distance b between a preset second reference point of the second mold member or the barrel mold and a molding surface of the second mold member is measured in advance, A molding die including a second die member and a body die is placed in a molding device,
The glass preform after heating is applied to the first mold member and the second mold member.
Pressure-molded by the mold member, and the pressure-molded glass lens sandwiched between the first mold member and the second mold member is taken out from the molding apparatus and cooled, and the glass lens shrinks by cooling. The mold member to follow, then measure the distance between the first reference point and the second reference point, and calculate the wall thickness of the glass lens based on the two distances a and b measured in advance. After that, the glass lens is taken out from the first mold member and the second mold member.