JP2022077734A - Glass lens molding device - Google Patents

Abstract

To provide a glass lens molding device capable of determining molding quality due to asymmetry deformation.SOLUTION: A glass lens molding device press-molds a glass material using a metal mold, and includes: a pair of metal molds sandwiching the glass material; a heating mechanism heating the glass material sandwiched by the pair of metal molds; a driving mechanism moving one of the pair of metal molds toward the other metal mold along a driving shaft in a press mold direction to press the metal material; a load detection device detecting load generated in a step of press molding the glass material; and a load center calculation part calculating a coordinate of the load center acting on the glass material in a flat surface orthogonal to the driving shaft in the step of press molding on the basis of the load detected by the load detection device.SELECTED DRAWING: Figure 1

Description

The present invention relates to a glass molding apparatus, specifically, a glass lens molding apparatus for mass-producing glass products such as lenses representing optical elements by a molding technique using a mold.

As a conventional glass lens molding device, in a device that press-molds glass softened by heating using a die, in order to detect the occurrence of tilt of the press shaft, it is placed on a movable shaft (or a fixed shaft). Some are provided with a 3-axis load detecting device (see, for example, Patent Document 1).

In the configuration diagram of the conventional glass lens molding apparatus described in Patent Document 1 shown in FIG. 13, dies 101 and 102 paired with each other are used. The glass material (not shown) is inserted into the lower mold 102, heated by an infrared lamp 107 that serves as a heater in a state of being close to the upper mold 101, and further in a softened state where the glass material reaches a predetermined temperature, and further a movable shaft. By raising 106, it is pressed by the upper mold 101 and the lower mold 102, and the mold shape is transferred to the glass to obtain a desired glass lens shape. After that, the output of the infrared lamp 107 is adjusted to lower the temperature to solidify the glass, and then the lower mold 102 is driven downward to take out the molded glass lens, and a series of glass forming processes is completed.

In recent years, glass lenses often adopt an aspherical shape for the purpose of improving performance and reducing the number of lenses. In particular, a lens that adopts an aspherical shape has only one optical axis on the aspherical side, and there is a problem that optical performance cannot be obtained if the molds arranged opposite to each other are tilted in the glass molding process. Becomes noticeable.

Therefore, in the glass lens molding apparatus described in Patent Document 1, when the axes of the upper die 101 and the lower die 102 are tilted by providing the 3-axis load detecting device, the generated processing resistances Fx and Fy are measured. It is detected and the detection result is calculated by the control device 116. Using the calculated value as a feedback signal, the axial attitude control unit 114 is driven in a direction for eliminating the tilt generated on the molding surface of the mold. As a result, the occurrence of tilt between the upper and lower axes is prevented, and the parallelism between the upper and lower molds can be ensured.

Japanese Patent Application Laid-Open No. 2003-246630

However, in the configuration of the conventional glass lens molding apparatus, since only the abnormality of parallelism between the molds arranged opposite to each other is measured, the abnormality of asymmetric deformation that may occur in the press molding of the glass material is detected. I couldn't. As a result, there is a problem that the shape of the lens surface is defective due to the strain caused by the asymmetric deformation after the molding is completed. There is still room for improvement in the conventional configuration from the viewpoint of further suppressing defects in glass lens molding.

It is an object of the present invention to solve the above-mentioned conventional problems and to provide a glass lens molding apparatus capable of determining quality quality due to asymmetric deformation during glass lens molding.

In order to achieve the above object, the glass lens molding apparatus according to the present disclosure is a glass lens molding apparatus by press molding a glass material using a mold, and is a pair with a pair of molds for sandwiching the glass material. A heating mechanism that heats the glass material sandwiched between the dies and the press by moving one of the pair of dies toward the other die along the drive shaft in the press forming direction. Based on the drive mechanism, the load detection device that detects the load generated in the press forming process of the glass material, and the load detected by the load detecting device, it acts on the glass material in the plane orthogonal to the drive axis in the press forming process. It is provided with a load center calculation unit for calculating the coordinates of the load center.

According to the glass lens molding apparatus of the present disclosure, it is possible to determine the quality quality due to asymmetric deformation during glass lens molding.

It is a partial front sectional view which shows the glass lens molding apparatus which detects the asymmetrical deformation which concerns on embodiment of this disclosure. It is sectional drawing which shows the press molding by the molding part of the glass lens molding apparatus of FIG. In general, it is a figure which shows the mode of the outer peripheral surface of a glass material after press molding. It is a figure which shows the state of the occurrence of asymmetrical deformation during press molding. It is a figure which shows one configuration example of the plane arrangement of the load sensor of the load detection device in the glass lens molding apparatus which concerns on embodiment of this disclosure. It is a figure which shows another configuration example of the plane arrangement of the load sensor of the load detection device. It is a figure which shows the position of the initial center of gravity of a glass material in the press molding by the glass lens molding apparatus 100 which concerns on embodiment of this disclosure. It is a figure which shows the position change of the load center of a glass material in the press molding by the glass lens molding apparatus which concerns on embodiment of this disclosure. It is a figure which shows the relationship between the molding eccentricity of a glass material, and the temperature difference which occurred by heating by a heater block in press molding. It is a block diagram which shows one configuration example of the arithmetic unit in the glass lens molding apparatus of FIG. It is a flowchart of the program of the arithmetic unit of FIG. It is a figure which shows an example which displays the coordinates of the load center by the display part of the arithmetic unit of FIG. 11 and the determination result of the molding quality of a glass lens. It is a partial front sectional view which shows the glass lens molding apparatus which performs the heating control which concerns on embodiment of this disclosure. It is a block diagram which shows one configuration example of the arithmetic unit in the glass lens molding apparatus of FIG. It is a flowchart of the program of the arithmetic unit of FIG. It is a figure which shows the structure of the conventional glass lens molding apparatus.

According to the first aspect of the present disclosure, it is a glass lens molding apparatus by press molding a glass material using a mold, and is sandwiched between a pair of molds for sandwiching the glass material and a pair of molds. A heating mechanism that heats the glass material, a drive mechanism that moves one of the pair of dies toward the other die along the drive axis in the press forming direction and presses the glass material. Based on the load detection device that detects the load generated in the press forming process and the load detected by the load detecting device, the load that calculates the coordinates of the center of load acting on the glass material on the plane orthogonal to the drive axis in the press forming process. Provided is a glass lens forming apparatus provided with a center calculation unit.

According to the second aspect of the present disclosure, the load detecting device includes at least three load sensors, and the load sensors are arranged axisymmetrically about the drive axis in the same plane orthogonal to the drive axis. Provided the glass lens molding apparatus according to the first aspect, which detects a load generated in the drive axis direction in a press molding step of a glass material.

According to the third aspect of the present disclosure, the load detection device detects the load in each of the drive axis direction and the directions of the two orthogonal axes in the plane orthogonal to the drive axis, and the load center calculation unit is detected. The glass lens molding apparatus according to the first aspect or the second aspect, which calculates the coordinates of the center of load by calculating the moments around two orthogonal axes based on the loads in three axial directions orthogonal to each other.

According to the fourth aspect of the present disclosure, the asymmetric deformation determination unit is further provided, and the asymmetric deformation determination unit determines the difference between the position corresponding to the coordinates of the load center calculated by the load center calculation unit and the center position of the drive shaft. The glass lens molding apparatus according to any one of the first to third embodiments, wherein it is determined whether or not a quality abnormality has occurred due to asymmetric deformation of the molded glass lens by comparing with a predetermined reference value. I will provide a.

According to the fifth aspect of the present disclosure, a display unit is further provided, and the display unit displays whether or not a quality abnormality has occurred due to asymmetrical deformation in the molded glass lens determined by the asymmetrical deformation determination unit. The glass lens molding apparatus according to a fourth aspect is provided.

According to the sixth aspect of the present disclosure, the display unit includes a display unit, and the display unit displays the coordinates of the load center calculated by the load center calculation unit in the press molding step of the glass material, according to the first to fourth aspects. The glass lens molding apparatus according to any one of them is provided.

According to the seventh aspect of the present disclosure, the glass lens according to the sixth aspect, wherein the display unit displays the change of the calculated coordinates of the plurality of load centers when the coordinates of the load center are calculated a plurality of times. A molding apparatus is provided.

According to the eighth aspect of the present disclosure, a molding eccentricity determination unit and a temperature difference calculation unit are further provided, and the molding eccentricity determination unit is a position corresponding to the coordinates of the load center calculated by the load center calculation unit. The difference between the position and the center position of the drive shaft is determined as the amount of molding eccentricity generated in the glass material in press molding, and the temperature difference calculation unit determines the amount of molding eccentricity stored in advance when there is a molding eccentricity amount. One of the first to seventh aspects, which calculates the temperature difference between the position corresponding to the coordinates of the load center and the center position of the drive shaft based on the relationship data between the amount and the temperature difference of heating by the heating mechanism. The glass lens molding apparatus according to one is provided.

According to the ninth aspect of the present disclosure, the heating mechanism includes at least two heating elements that can independently adjust the heating temperature and a heating control unit that adjusts the output of the heating element, and the heating control unit is a glass material. The glass lens molding apparatus according to an eighth aspect is provided, wherein when a temperature difference is calculated in the press molding step of the above, the output of a heating element whose heating temperature can be adjusted is adjusted so as to eliminate the temperature difference.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. It should be noted that all of the embodiments described below show a preferred specific example of the present disclosure. Therefore, the numerical values, shapes, materials, components, arrangement positions of the components, connection modes, and the like shown in the following embodiments are specific examples of the present disclosure and do not limit the present disclosure. .. Therefore, among the components in the following embodiments, the components not described in the independent claims indicating the highest level concept of the present disclosure will be described as arbitrary components. In addition, changes may be made as appropriate without departing from the scope of the effect of the present disclosure. Furthermore, it can be combined with other embodiments.

It should be noted that each drawing shows a schematic diagram and is not necessarily exactly illustrated. Further, in each drawing, substantially the same configuration is designated by the same reference numeral, and duplicate description will be omitted or simplified.

<< Embodiment >>
<Structure of the glass lens molding apparatus according to the embodiment of the present disclosure>
FIG. 1 is a partial front sectional view showing a glass lens molding apparatus 100 for detecting an asymmetric deformation according to an embodiment of the present disclosure. The glass lens molding apparatus 100 for detecting asymmetric deformation shown in FIG. 1 includes a molding unit 10, a load detecting apparatus 20, and an arithmetic unit 30. First, the constituent members constituting the molded portion 10 will be described.

As shown in FIG. 1, in the molding portion 10, the glass material 5 is shown in a melt-softened state. The glass lens molding die used for the molding section 10 includes a lower die (lower punch) 3 and an upper die (upper punch) 2 arranged opposite to each other, and is held by the sleeve 4. The heater block 7 is installed so as to be in contact with the upper mold 2 and the lower mold 3, respectively, and a plurality of heating elements 6 are inserted inside the heater block 7.

In order to prevent the heat of the heating element 6 from being transmitted to the entire molded portion 10, heat insulating plates 8 are arranged on the opposite sides of the upper and lower heater blocks 7 to the molds. A press drive shaft of the molding portion 10 is installed above the upper mold 2 (not shown), and below the lower mold 3 via a heater block 7 and a heat insulating plate 8, a load sensor of the load detecting device 20 is installed. 21 is installed (the load detecting device 20 will be described later).

In addition, in FIG. 1, the upper die 2 and the lower die 3 are shown to be in contact with the heater block 7, but this is because the state of the heat transfer method is shown, and they can be separated if necessary. .. Further, the heating method may be induction heating, lamp heating, or the like.

In addition, the pressurizing part that is indispensable as a molding device, the driving part for moving the mold, the heating device including the heating / temperature measuring part necessary for melting and softening the glass, and the production process by controlling them. The control device to be executed is a natural function as a general glass lens molding device, and the method is not particularly limited in the present disclosure, and thus the description thereof is omitted. Further, in the glass lens molding step, since a temperature range of about 600 ° C. is generally used, an atmosphere control such as a nitrogen atmosphere or a vacuum is provided. Since these are also configured to be appropriately adopted according to the characteristics of the production method and the equipment, they are not specified in particular in this disclosure.

<Press molding process of the glass lens molding apparatus according to the embodiment of the present disclosure>
Hereinafter, the operation of the molding unit 10 of the glass lens molding apparatus 100 for detecting the asymmetrical deformation according to the embodiment of the present disclosure will be described with reference to FIG. FIG. 2 is a cross-sectional view showing press molding by the molding portion 10 of the glass lens molding apparatus 100 of FIG.

FIG. 2A shows a state before the start of press molding. The glass material 5a to be a lens is inserted in a state where the upper mold 2 and the lower mold 3 are separated from each other before the pressing is started, and is sandwiched between the lower mold 3 and the upper mold 2. The heating element 6 is controlled to a predetermined temperature by a control device (not shown). When a predetermined temperature or a predetermined time has elapsed, the upper die 2 is driven by a driving unit (not shown), moves in the pressing direction P along the driving shaft 11, and pressing is started. As a result, the melt-softened glass material 5a is press-molded between the upper mold 2 and the lower mold 3.

FIG. 2B shows a state in which press molding is completed. The glass material 5a is pressed in a melt-softened state and formed into a 5b having a lens surface shape. In the press molding shown in FIG. 2, only the lens surface shape is formed, and the outer peripheral surface of the lens is not formed at the same time. After the press molding is completed, the temperature of the heating element 6 is lowered, and the glass material 5b having the lens surface shape is solidified and then taken out from the mold, and is centered so as to have a predetermined diameter to obtain the outer peripheral surface of the lens. Is molded into a finished glass lens.

<Occurrence of asymmetric deformation in press molding>
FIG. 3 is a diagram showing the appearance of the outer peripheral surface of the glass material 5b after press molding in general. In the centering process after press molding, the outer peripheral surface is machined along the planned centering line 5c1. When the completed glass lens is assembled to the lens barrel, the outer peripheral surface of the lens is held. Therefore, if the center of the outer peripheral surface of the lens does not coincide with the optical axis, sufficient optical performance cannot be exhibited. Therefore, as shown in FIG. 3A, it is desirable that the outer peripheral surface 5b1 of the glass material after press molding is axisymmetrically molded and has a concentric shape with the planned centering line 5c1. On the other hand, as shown in FIG. 3B, the outer peripheral surface 5b2 of the glass material after press molding is asymmetrically deformed. Due to such deformation, it does not become concentric with the planned centering line 5c2, and the optical performance of the lens is affected.

Regarding the cause of the asymmetric deformation in the press molding, it is considered that the glass material was not placed in the center of the mold but was placed in an unbalanced position before the start of the press molding. In this case, even if the softening point of the glass is reached and the deformation starts with a predetermined pressing force, the glass spreads in a direction in which the glass is easily deformed, that is, in a wide direction of the gap between the upper mold and the lower mold, so that the glass does not spread uniformly. Asymmetric deformation occurs.

The second is the case where the temperature distribution on the mold surface is non-uniform. Specifically, since the temperature at which the glass is in a melt-softened state is higher than the glass transition point (Tg), the viscosity of the glass changes significantly if the temperature is slightly different. Therefore, if the contact surface between the heater block and the mold has a non-uniform temperature, the viscosity of the glass in the portion heated to a higher temperature drops sharply, and the deformation easily spreads to the side with the lower viscosity. As a result, the glass material does not spread uniformly, resulting in asymmetric deformation.

When asymmetric deformation occurs due to any of the causes, the glass after press molding has non-rotational symmetric strain, so that the finished lens cannot be achieved with sufficient accuracy, resulting in poor quality.

Next, with reference to FIG. 4, the change in the glass material when asymmetrical deformation occurs during press molding will be examined.

FIG. 4 is a diagram showing the occurrence of asymmetrical deformation during press molding. In FIG. 4A, the glass material 5c is sandwiched between the upper mold 2 and the lower mold 3. At this time, the glass material 5c is tentatively installed in the center of the upper mold 2 and the lower mold 3. That is, the center of gravity 12a of the glass material 5c is on the drive shaft 11. After the glass material 5c is sandwiched and the glass forming temperature is reached by the heating device (not shown), the upper mold 2 is lowered along the drive shaft 11 by the drive unit (not shown), and press forming is started. Will be done.

FIG. 4B shows a state in which the lens is axisymmetrically molded without asymmetric deformation during press molding. At this time, the glass material 5d being press-molded is evenly spread in the m1 and m2 directions around the drive shaft 11. In this case, in the glass material 5d being press-molded, the load center 12b in the press direction P is on the drive shaft 11 without moving the center of gravity.

FIG. 4C shows a state in which asymmetrical deformation occurs during press molding and the lens is not molded axially symmetrically. At this time, the glass material 5e being press-formed does not spread uniformly with respect to the drive shaft 11, and the spread proceeds in the m4 direction rather than the m3 direction, so that the center of gravity of the glass material 5e moves and the press direction P. The position of the load center 12c in the above position is displaced by Δd with respect to the drive shaft 11.

As described above, the movement of the load center during pressing occurs due to the occurrence of asymmetrical deformation during press forming. In the present disclosure, as will be described later, by measuring the movement of the center of load during pressing, it is possible to measure the asymmetric deformation of the molded glass lens and determine the molding quality.

<Load detection device of glass lens molding device according to the embodiment of the present disclosure>
Next, the configuration of the load detecting device 20 will be described. As shown in FIG. 1, the load detection device 20 includes a load sensor 21 and an amplifier 22. The load sensor 21 is installed below the heat insulating plate 8 of the molding portion 10 and measures the load at the time of pressing. The detected load value is amplified by the amplifier 22 and transmitted to the arithmetic unit 30.

FIG. 5 is a diagram showing a configuration example of a planar arrangement of the load sensor 21 of the load detection device 20 in the glass lens molding device 100 according to the embodiment of the present disclosure. The load sensor 21 shown in FIG. 5 shows a configuration example using four uniaxial load sensors (21a1,21a2, 21a3, 21a4) capable of measuring a load only in the press direction (Z-axis). This configuration is practical because it can be configured only with an inexpensive uniaxial load sensor. As shown in FIG. 5, the four uniaxial load sensors 21a1 to 21a4 are installed at positions ± m with respect to the X axis and ± n with respect to the Y axis in a plane orthogonal to the drive axis, respectively. .. In this way, the load sensor is arranged symmetrically with respect to the origin O of the XY coordinates in order to facilitate the calculation for deriving the coordinates of the load center described later, and the load sensor is not arranged symmetrically. In that case, the calculation of the coordinates of the load center becomes complicated. The virtual surface from which the position of the center of load is derived is defined as the working surface F1 and is the plane of the XY coordinates shown in FIG. When a pressing force is generated during press molding, the uniaxial load sensors 21a1 to 21a4 detect the Z-axis loads z1, z2, z3, z4, respectively, and the Z-axis load on the working surface F1 is the total value of z1 to z4. Will be.

When the four load sensors 21a1 to 21a4 each indicate the load z1 to z4 on the Z axis, the moment Mx around the X axis and the moment My around the Y axis centering on the origin O of the XY coordinates are as follows. It is calculated by the equations (1) and (2) of.

(Number 1)
Mx = -m (z1 + z2) + m (z3 + z4) (1)
My = -n (z1 + z4) + n (z2 + z3) (2)

The coordinates (a _x1 , _ay1 ) of the load center G1 on the working surface F1 can be obtained by the following equations (3) and (4).

When the center position of the drive shaft 11 of the mold 1 of the molding unit 10 coincides with the origin O of the XY coordinates of the working surface F1, molding is performed from the start of press molding until the glass is in a spread state. When the later glass material is in the state of FIG. 3A, the load center G1 coincides with the origin O of the XY coordinates, and the calculation results of the equations (3) and (4) are a _x1 = a _y1 ≈ It can be estimated that it will be 0. On the other hand, when the glass material after molding is in the state of FIG. 3B, asymmetric deformation occurs in the glass material during press molding, and the load center G1 moves from the origin O of the XY coordinates, and the formula ( 3) The calculated values of the coordinates a _x1 and a _y1 of the load center G1 according to (4) do not become zero.

In the configuration example of the load sensor 21 shown in FIG. 5, four uniaxial load sensors are arranged, but if the load sensor 21 has three or more, the coordinates of the load center can be calculated. When three load sensors 21 are used, the three load sensors 21 may be arranged at three locations that are not on a straight line. For example, the three load sensors 21 can be arranged in three of the four regions from the first quadrant to the fourth quadrant on the XY plane.

Further, the load sensor 21 shown in FIG. 5 uses a uniaxial load sensor, but the present disclosure is not limited to this. For example, the configuration example shown in FIG. 6 is also possible. FIG. 6 is a diagram showing another configuration example of the plane arrangement of the load sensor 21 of the load detection device 20. In the configuration example shown in FIG. 6, one 6-axis load sensor 21b is arranged. According to the 6-axis load sensor, all force components, that is, translational forces Fx, Fy, Fz of 3 axes XYZ axes orthogonal to each other, and moments Mx, My, Mz around each axis are simultaneously present. Since it is output, the coordinates of the load center of the object to be measured can be calculated more easily. Examples of such a 6-axis load sensor include TL6F04 manufactured by Tech Gihan Co., Ltd.

The 6-axis load sensor 21b indicates the translational forces Fx, Fy, Fz of the XYZ axes and the moments Mx, My, Mz around the respective axes, and the vertical distance between the 6-axis load sensor 21b and the working surface F2. When is _az , the coordinates ( _ax2 , _ay2 ) of the load center G2 on the working surface F2 can be obtained by the following equations (5) and (6).

(Number 3)
a _x2 =-(My-Fx · _az ) / Fz (5)
a _y2 = (Mx + Fy · a _z ) / Fz (6)

Similar to the case where four load sensors are used, when the center position of the drive shaft 11 of the die 1 of the molding unit 10 coincides with the origin O of the XY coordinates of the working surface F2, after the press molding starts. When the molded glass material is in the state shown in FIG. 3A until the glass is spread out, the load center G2 coincides with the origin O of the XY coordinates, and the equations (5) and (6) ) Can be estimated to be a _x2 = a _y2 ≈ 0. On the other hand, when the glass material after molding is in the state of FIG. 3B, asymmetric deformation occurs in the glass material during press molding, and the load center G2 moves from the origin O of the XY coordinates, and the formula ( 5) The calculated values of the coordinates a _x2 and a _y2 of the load center G2 according to (6) do not become zero.

Further, as the load sensor 21 of the load detection device 20, even if another detector capable of measuring the load, for example, a force plate in which four detectors capable of measuring the load of the XYZ3 axes are arranged is used. Similarly, it is possible to calculate the coordinates of the center of load.

As shown in FIG. 1, the load sensor 21 is arranged below the heat insulating plate 8. The load sensor may drift due to temperature changes, and it is effective to devise so that the temperature changes are small in order to measure the load more accurately. In FIG. 1, the heater block 7 and the sensor 21 are in contact with each other via a relatively thin heat insulating material 8, but for the purpose of protecting the load sensor 21 from high temperature and temperature change, the heater block 7 and the sensor 21 are connected via a multi-layered thick heat insulating material. They may be placed apart.

<Movement of the load center of the glass material in press molding>
If the asymmetrical deformation shown in FIG. 4 occurs as the press progresses during the press molding of the glass lens, the load center moves in the XY plane. Hereinafter, with reference to FIGS. 7 to 9, the movement mode of the load center of the glass material during press molding and the cause of the movement will be described.

FIG. 7 is a diagram showing the position of the initial center of gravity of the glass material in press molding by the glass lens molding apparatus 100 according to the embodiment of the present disclosure, and FIG. 8 is a diagram showing the position of the initial center of gravity of the glass material, and FIG. 8 is a diagram showing the glass lens molding apparatus according to the embodiment of the present disclosure. It is a figure which shows the position change of the load center of the glass material on the working surface in the press molding by.

The position of the center of initial load changes depending on the position of the initial center of gravity when the glass material is installed before the start of press forming. The glass material 5a1 shown in FIG. 7A is sandwiched between the upper mold 2 and the lower mold 3, and the center of gravity A00 of the glass material 5a1 is on the drive shaft 11 of the mold 1. In this case, the center of the initial load of the glass material 5a1 coincides with the origin O of the XY coordinates on the working surface shown in FIG. On the other hand, in the glass material 5a2 shown in FIG. 7B, the center of gravity A01 is sandwiched with an offset Δd0 with respect to the drive shaft 11 of the mold 1. In this case, the center of the initial load of the glass material 5a2 is A1 which is separated from the origin O of the XY coordinates on the working surface shown in FIG. Generally, when the glass material is a spherical "ball glass material", the position where the glass material is sandwiched may shift due to the installation of the glass material in the mold or the transportation of the mold. As a result, as shown in FIG. 7, when the initial center of gravity position of the glass material is installed with an offset with respect to the drive shaft of the mold, as shown in FIG. 8, the initial position of the glass material is set at the start of press molding. The position of the center of gravity exists away from the origin of the XY coordinates on the plane of action.

As shown in FIG. 8, the initial load center A1 (position ■ shown in FIG. 8) of the glass material on the working surface at the start of press molding is further aligned with the origin of the XY coordinates along the locus Q1 as the press molding progresses. It moves in the direction away from O, and when the press molding is completed, it becomes A2 (● position shown in FIG. 8) farthest from the origin O of the XY coordinates. As will be described later, let γ be the angle formed by the straight line A1A2 connecting the final load center A2 at the completion of press molding and the origin O of the XY coordinates and the X axis. This angle γ is an angle indicating the spreading direction of the pressed glass material on the working surface (XY plane) during press molding, and indicates the direction in which the asymmetrical deformation of the glass material proceeds during press molding. ing.

The reason why the asymmetrical deformation of the glass material proceeds in the γ direction during press molding is that the temperature in that direction is slightly high. This is because the temperature at which the glass is formed is higher than the glass transition point (Tg point), so that the viscosity greatly differs due to a slight temperature difference. Therefore, if temperature unevenness occurs on the molding surfaces of the upper mold 2 and the lower mold 3 even a little, the viscosity of the glass becomes lower as the temperature is higher, so that the glass flows to the side where the temperature is higher. That is, the movement of the center of load shown in FIG. 8 is caused by a slight temperature difference generated on the contact surface between the heater block 7 of the molding portion 10 and the mold 1 shown in FIG. 1, and the moving direction thereof is determined. The temperature distribution of the contact surface is higher.

The relationship between the amount of change in the load center position of the glass material and the temperature difference generated in the heater block during press molding will be further described with reference to FIG. FIG. 9 is a diagram showing the relationship between the molding eccentricity of the glass material and the temperature difference caused by heating by the heater block in press molding. FIG. 10A shows the molding eccentricity amount δ on the working surface from which the coordinates of the load center of the glass material 5b3 in which the asymmetric deformation has occurred are derived. In this working surface, when the scheduled centering line of the lens to be molded is the circle L1 and the circle circumscribing the outer circumference of the glass material 5b3 is the circle L2, the difference between the center O1 of the circle L1 and the center O2 of the circle L2 is set. The molding eccentricity amount δ. FIG. 10B shows the relationship between the molding eccentricity δ of the glass material generated during press molding and the temperature difference generated on the contact surface between the heater block 7 and the mold 1 shown in FIG. There is. When the molding eccentricity δ is large, the temperature difference in heating by the heater block is also large. Based on this result, it is considered that the amount of molding eccentricity can be reduced and the asymmetrical deformation of the glass material can be improved by controlling the heating temperature so as to eliminate the temperature difference in heating due to the heater block. However, the relationship between the amount of molding eccentricity of the glass material and the temperature difference caused by heating by the heater block differs depending on the type of glass to be molded, the shape and size of the lens, and the configuration of the glass lens molding device, so the heating temperature is controlled. In order to improve the asymmetrical deformation by doing so, it is necessary to clarify the peculiar relationship between the molding eccentricity δ of the lens to be molded and the temperature difference caused by heating by the heater block, and to acquire mapping data. ..

As described above, during press molding, the load center of the glass material to be molded moves due to the temperature difference generated by heating by the heater block. As a result, asymmetrical deformation occurs, which causes poor quality of the glass lens. Based on this, the present disclosure aims to determine and improve asymmetric deformation by calculating the position of the load center of the glass material during press molding.

<Determination of asymmetric deformation in the glass lens molding apparatus according to the embodiment of the present disclosure>
Hereinafter, in the glass lens molding apparatus 100 according to the present disclosure, determination of asymmetric deformation by calculation of the load center of the glass material will be described.

The configuration of the arithmetic unit 30 according to the embodiment of the present disclosure will be described with reference to FIG. 10. FIG. 10 is a block diagram showing a configuration example of the arithmetic unit 30 in the glass lens molding apparatus 100 of FIG.

<Arithmetic logic unit 30 (computer device)>
The arithmetic unit 30 is, for example, a computer device. As this computer device, a general-purpose computer device can be used, and for example, as shown in FIG. 10, includes a processing unit 31, a storage unit 32, and a display unit 33. Further, an input device, a storage device, an interface and the like may be included. The arithmetic unit 30 can perform arithmetic processing based on the load data during press molding detected by the load detection apparatus 20.

<Processing unit 31>
The processing unit 31 may be, for example, a central processing unit (CPU), a microcomputer, or a processing device capable of executing instructions that can be executed by the computer.

<Memory unit 32>
The storage unit 32 may be, for example, at least one of ROM, EEPROM, RAM, flash SSD, hard disk, USB memory, magnetic disk, optical disk, magneto-optical disk and the like.

The storage unit 32 includes the program 35. When the arithmetic unit 30 is connected to the network, the program 35 may be downloaded from the network as needed.

<Program 35>
The program 35 can include a load center calculation unit 35a and an asymmetric deformation determination unit 35b. The load center calculation unit 35a and the asymmetric deformation determination unit 35b are read from the storage unit 32 and executed by the processing unit 31 at the time of execution. The load center calculation unit 35a and the asymmetric deformation determination unit 35b calculate the position of the load center of the glass material during press molding, and further, based on the movement of the load center, an asymmetric deformation occurs and the molded glass lens. It is possible to determine whether or not a quality abnormality has occurred in the glass.

<Display unit>
The display unit 33 can display, for example, the result obtained by executing the program 35 by the processing unit 31.

A program for determining the molding quality of a glass lens due to asymmetric deformation by calculating the load center will be described with reference to FIG. 11. FIG. 11 is a flowchart of the program 35 of the arithmetic unit 30 of FIG. As shown in FIG. 11, the program 35 of the arithmetic unit 30 includes the following three steps. The load center calculation unit 35a corresponds to steps S11 and S12, and the asymmetric deformation determination unit 35b corresponds to step S13.
(1) Based on the load detected by the load detecting device, the coordinates of the load center of the molded glass material are calculated (S11).
(2) Next, the position change of the load center during press molding is calculated from the coordinates of the load center calculated in time series (S12).
(3) Next, on the working surface from which the coordinates of the load center were derived, the difference between the position of the load center and the center position of the drive shaft at the completion of press molding was compared with a predetermined reference value. It is determined whether or not a quality abnormality has occurred due to asymmetric deformation of the glass lens (S13).

FIG. 12 is a diagram showing an example of displaying the coordinates of the center of load and the determination result of the molding quality of the glass lens by the display unit 33 of the arithmetic unit 30 of FIG. For each press molding of the glass lens, the initial load center (B1, C1 shown in FIG. 12) at the start of molding and the post-press load center (B2, C2 shown in FIG. 12) at the completion of molding can be displayed. Further, the position change of the load center during press molding, for example, the loci Q1 and Q2 of moving from the position of the initial load center to the position of the post-press load center may be displayed. Further, in order to show the determination result of the molding quality of the molded glass lens, the area classification of the non-defective product and the defective product may be displayed. In the working surface from which the coordinates of the load center shown in FIG. 12 are derived, the farther away from the center position of the drive shaft (the intersection of the XY axes), the more defective the product becomes. It is also possible to distinguish and display the outside of C as the "defective area" R2. The circumference C that draws the line between the good product and the defective product can be changed depending on the model of the lens to be produced. By displaying the display unit 33, it is possible to confirm the quality status that changes from moment to moment during press molding in real time.

<Heating control in the glass lens molding apparatus according to the embodiment of the present disclosure>
Subsequently, with reference to FIGS. 13 to 15, a glass lens molding apparatus that performs heating control according to the present disclosure will be described. FIG. 13 is a partial front sectional view showing a glass lens molding apparatus 100a that controls heating according to the embodiment of the present disclosure.

In the glass lens molding apparatus 100a shown in FIG. 13, the molding portion 10a has the same configuration as the molding portion 10 of the glass lens molding apparatus 100 shown in FIG. 1 except that the heating element 6a and the heating control unit 40 are included. Details of the same configuration as the molding unit 10 of the glass lens molding apparatus 100 shown in FIG. 1 will be omitted. The heating control unit 40 can adjust the output of the heating element 6a based on the calculation result of the arithmetic unit 30a. The heating element 6a includes at least two heating elements, each of which can independently adjust the heating temperature.

FIG. 14 is a block diagram showing a configuration example of the arithmetic unit 30a in the glass lens molding apparatus 100a of FIG. The arithmetic unit 30a includes a processing unit 31, a storage unit 32a, and a display unit 33, similarly to the arithmetic unit 30 shown in FIG. Further, an input device, a storage device, an interface and the like may be included. The arithmetic unit 30 can perform arithmetic processing based on the load data during press molding detected by the load detection apparatus 20, and transmit the result to the heating control unit. Since the processing unit 31 and the display unit 33 of the arithmetic unit 30a have the same configuration as that of the arithmetic unit 30, detailed description thereof will be omitted. Hereinafter, the configuration of the storage unit 32a will be described.

<Memory unit 32a>
The storage unit 32a may be, for example, at least one of ROM, EEPROM, RAM, flash SSD, hard disk, USB memory, magnetic disk, optical disk, magneto-optical disk and the like.

The storage unit 32a includes the program 36. When the arithmetic unit 30a is connected to the network, the program 36 may be downloaded from the network as needed.

<Program 36>
The program 36 can include a load center calculation unit 36a, a molding eccentricity determination unit 36b, and a temperature difference calculation unit 36c. At the time of execution, the load center calculation unit 36a, the asymmetric deformation determination unit 36b, and the temperature difference calculation unit 36c are read from the storage unit 32a and executed by the processing unit 31, and the result is transmitted to the heating control unit 40. To.

A program 36 for controlling heating in the glass lens molding apparatus 100a will be described with reference to FIG. FIG. 15 is a flowchart of the program 36 of the arithmetic unit 30a of FIG. As shown in FIG. 15, the program 36 of the arithmetic unit 30a includes the following four steps. The load center calculation unit 36a corresponds to step S21, the asymmetric deformation determination unit 36b corresponds to step S22, and the temperature difference calculation unit 36c corresponds to steps S23 and S24.
(1) Based on the load detected by the load detecting device, the coordinates of the load center of the molded glass material are calculated (S21).
(2) Next, on the working surface from which the coordinates of the load center are derived, the difference between the position corresponding to the calculated coordinates of the load center and the center position of the drive shaft is set to the molding eccentricity of the glass material being molded. As the amount, it is determined whether or not the molding eccentricity amount has occurred (S22).
(3) Next, when it is determined that the molding eccentricity has occurred, the heater block 7 and the mold 1 are based on the relationship data between the molding eccentricity stored in advance and the temperature difference of heating by the heating mechanism. On the contact surface of the above, the temperature difference between the position corresponding to the coordinates of the center of load and the center position of the drive shaft is calculated (S23).
(4) Next, the calculated temperature difference is transmitted to the heating control unit 40 (S24).

The heating control unit 40 can adjust the output of the corresponding heating element 6a based on the result of the temperature difference calculated by the arithmetic unit 30a. For example, by reducing the output of the heating element 6a arranged on the side where the heating temperature is high, the temperature difference generated on the contact surface between the heater block 7 and the mold 1 is eliminated, and the glass material is asymmetric during press molding. Deformation can be improved.

In the press molding process, the process time is completely different depending on the shape of the lens to be molded. In the glass lens molding apparatus 100a shown in FIG. 13, since the heating temperature is controlled, it is easier to control when the time required for molding the lens is long, and the difficulty is high for the lens having a short molding time.

In the embodiment of the present disclosure described above, the load sensor 21 is installed on the lower side of the lower mold 3, but the present disclosure is not limited to this. For example, even if it is installed on the upper side of the upper die 2, the load can be detected in the same manner.

Further, the present invention is not limited to the above embodiment, and can be carried out in various other embodiments. For example, in the above description, only the rotationally symmetric lens shape has been mentioned, but in the molding of a deformed lens, the difference value of the load center for each molding is based on the movement of the load center in the normal non-defective molding process. Can be applied widely as well by calculating.

Although the present disclosure has been fully described in connection with preferred embodiments with reference to the accompanying drawings, various modifications and modifications are obvious to those skilled in the art. It should be understood that such modifications and modifications are included within the claims of the invention, as long as they do not deviate from the scope of the invention according to the appended claims.

The glass lens molding apparatus of the present invention can determine the quality quality due to asymmetric deformation during glass lens molding, and can further produce a highly accurate glass lens. Further, it can be similarly used in the molding of resin lenses having significantly different temperature ranges.

1 Mold 2 Upper mold 3 Lower mold 4 Sleeve 5 Glass material 5a Glass material before press molding 5b Glass material after press molding 5c, 5d, 5e Glass material during press molding 6, 6a Heating element 7 Heater block 8 Insulation plate 10,10a Molding unit 11 Drive shaft 20 Load detection device 21 Load sensor 21a1,21a2,21a3,21a4 1-axis load sensor 21b 6-axis load sensor 22 Amplifier 30,30a Calculation device 31 Calculation unit 32,32a Storage unit 33 Display unit 35 , 36 Program 40 Heating Control Unit 100, 100a Glass Lens Molding Equipment

Claims (9)

A glass lens molding device that press-molds a glass material using a mold.
A pair of molds that sandwich the glass material and
A heating mechanism that heats the glass material sandwiched between the pair of molds,
A drive mechanism for pressing one of the pair of dies by moving it toward the other die along a drive axis in the press forming direction.
A load detection device that detects the load generated in the press molding process of the glass material, and
A load center calculation unit that calculates the coordinates of the load center acting on the glass material on a plane orthogonal to the drive axis in the press forming process based on the load detected by the load detection device.
To prepare
Glass lens molding equipment. The load detector includes at least three load sensors.
The load sensor is
They are arranged axisymmetrically about the drive shaft in the same plane orthogonal to the drive shaft, and each detects a load generated in the drive shaft direction in the press forming process of the glass material.
The glass lens molding apparatus according to claim 1. The load detecting device detects the load in each of the driving axis direction and the two orthogonal axes in the plane orthogonal to the driving axis.
The load center calculation unit calculates the coordinates of the load center by calculating the moments around the two orthogonal axes based on the detected loads in the three axial directions orthogonal to each other.
The glass lens molding apparatus according to claim 1 or 2. Further equipped with an asymmetric deformation determination unit,
The asymmetric deformation determination unit is
By comparing the difference between the position corresponding to the coordinates of the load center calculated by the load center calculation unit and the center position of the drive shaft with a predetermined reference value, the formed glass lens is deformed asymmetrically. Judging whether or not a quality abnormality has occurred,
The glass lens molding apparatus according to any one of claims 1 to 3. With more display
The glass lens molding apparatus according to claim 4, wherein the display unit displays whether or not a quality abnormality has occurred in the molded glass lens due to the asymmetric deformation, which is determined by the asymmetric deformation determination unit. Equipped with a display
The display unit is
In the press molding process of the glass material, the coordinates of the load center calculated by the load center calculation unit are displayed.
The glass lens molding apparatus according to any one of claims 1 to 4. The display unit is
When the coordinates of the load center are calculated a plurality of times, the changes in the coordinates of the plurality of calculated load centers are displayed.
The glass lens molding apparatus according to claim 6. Further equipped with a molding eccentricity determination unit and a temperature difference calculation unit,
The molding eccentricity determination unit determines the difference between the position corresponding to the coordinates of the load center calculated by the load center calculation unit and the center position of the drive shaft, and the molding deviation generated in the glass material in the press molding. Judged as the core amount,
The temperature difference calculation unit is the coordinates of the load center based on the relationship data between the molding eccentricity stored in advance and the temperature difference of heating by the heating mechanism when the molding eccentricity is present. Calculate the temperature difference between the position corresponding to the above and the center position of the drive shaft.
The glass lens molding apparatus according to any one of claims 1 to 7. The heating mechanism is
It includes at least two heating elements that can independently adjust the heating temperature and a heating control unit that adjusts the output of the heating element.
The heating control unit
When the temperature difference is calculated in the press molding process of the glass material,
The output of the heating element whose heating temperature can be adjusted is adjusted so as to eliminate the temperature difference.
The glass lens molding apparatus according to claim 8.

Images