JP2011007726A - Apparatus and method for measuring heat caulking resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and method for measuring heat caulking resistance, for determining whether a caulking pressure applied to a heat caulking portion of an optical lens is an appropriate range so as not to leave a distortion at a lens or a lens frame without troublesome work or use of a large-scale apparatus.SOLUTION: The measuring apparatus 10 includes: a placement member 12 on which the lens frame 52 is placed so as not to rotate; a retaining member 20 provided with a venting hole for communicating a discharge port 15 of a sucker 16 for sucking the optical lens 51 with an air hose 35 connected to a vacuum pump 34; and a rotating type load measuring instrument 25 for gripping the retaining member 20. The rotating type load measuring instrument 25 displays measurements in real time during measurement on a display unit 27 provided on the top face when the instrument body 26 is turned and a maximum during one measurement. By a support hole 44 formed in a support arm 43 of a support base 40, the retaining member 20 is supported to be rotatable and liftable.

Description

  The present invention relates to a measuring apparatus and a measuring method for measuring the fixing strength of an optical lens that is heat caulked inside a cylindrical lens frame.

  The optical lens is housed inside a cylindrical lens frame made of a thermoplastic resin such as ABS, polystyrene (PS), polypropylene (PP) or polycarbonate (PC), and the cylindrical shape of the lens frame is formed by a heat caulking device. The caulking margin is pressed in a heated state and plastically deformed to fix the optical lens. Prior to the caulking operation, the thermal caulking device performs alignment between the caulking margin portion and the heater chip. However, the optical lens is a precision component and requires high-accuracy alignment. In addition, since the caulking margin that is crushed by the optical lens has a ring shape, not only the center alignment but also the plane parallelism must be ensured, and the alignment operation requires skill.

  In Patent Document 1 below, an adjustment jig provided with a stylus-type position measuring device on a pedestal having the same rotation center as the center of the lens frame to be heat caulked is placed on the cradle of the lens frame, and the heat caulking device is attached. Adjusting the position of the cradle with the heater chip and the lens frame cradle attached, and then performing crimping on the lens frame without removing the heater chip and cradle, to achieve high-accuracy thermal caulking An adjustment jig and an adjustment method for a heat caulking device are described.

JP 2007-245502 A

  However, even if heat caulking is performed with high accuracy, if the pressure during caulking is too strong, distortion occurs in the caulked lens. If the caulking force is too weak, the lens may become loose during use. What is necessary is just to find out whether it is crimping with the right pressure with respect to these problems, and should just measure the crimping intensity | strength of a lens. For example, if the distortion of the optical surface of the squeezed lens is checked using an interferometer, it is possible to exclude those whose squeezing pressure is too high. However, the inspection by the interferometer is time-consuming and causes a cost increase. Further, in order to exclude a lens with a small caulking force, a method is considered in which a predetermined pressure is applied to the optical lens caulked in the lens frame from a direction opposite to the caulking direction to check whether or not the optical lens is disengaged. In this method, the pressure applied to the lens that has not been detached may remain as stress and cause deterioration of heat caulking, which may lead to a defective reserve army.

  In view of the above problems, the present invention measures that the caulking pressure applied to the thermal caulking portion of the optical lens is within an appropriate range without using a laborious operation or a large-scale apparatus and leaving distortion in the lens or the lens frame. An apparatus and a method for measuring the thermal caulking intensity are proposed.

  An apparatus for measuring thermal caulking strength according to the present invention includes a mounting member that supports a lens frame on which an optical lens is caulked in a non-rotatable manner, a suction cup that is attracted to the optical surface of the optical lens, and a holding member for the suction cup. And a rotational load measuring device such as a torque meter or a torque gauge for measuring a static friction load immediately before the optical lens starts to rotate by applying a rotational force. The holding member may be provided with a vent hole formed in the suction cup for communicating the air in the suction cup and the other end of the air hose having a vacuum pump connected to one end. A support arm on which the holding member is fixed may be provided with a support arm on which the holding member is rotatably mounted about the optical axis of the optical lens and is movable up and down.

  The thermal caulking intensity measuring method according to the present invention includes a first step of placing the lens frame on which the optical lens is heat caulked on the mounting member in a non-rotatable manner, and a second step of adsorbing the suction cup to the optical surface of the optical lens. Rotate the suction cup holding member, gradually increase the rotational force, and measure the maximum value of the static friction load immediately before the optical lens starts rotating against the caulking force with a rotary load measuring instrument The third step is sequentially performed. The holding member gripped by the rotary load measuring device is attached to the support base to which the mounting member is fixed, so that the holding member is rotatable about the optical axis and can be moved up and down, and rotates to the rotary load measuring device. It is preferable that a force is applied to rotate the suction cup so that the maximum value of the static friction load is measured.

  According to the apparatus and method for measuring the thermal caulking strength according to the present invention, an excessive force that deforms the thermal caulking portion of the lens frame is not applied to the thermal caulking portion of the lens frame during the caulking strength measurement. There is no stress left on the lens, and a defective reserve army is not created by measuring the caulking strength.

It is a figure which shows the structure of the measuring apparatus of the thermal crimping intensity | strength by this invention. It is the figure which looked at the lens frame where the optical lens by which thermal crimping intensity | strength is measured was crimped from the top. It is the figure of the external appearance (left) and center cross section (right) which looked at the lens frame of FIG. 2 from the side. It is a figure which shows a holding member and a suction cup. It is the figure which mounted the lens frame to measure in a measuring device. It is the figure which made the suction cup adsorb | suck to an optical lens.

  A thermal caulking intensity measuring apparatus (hereinafter simply referred to as a measuring apparatus) 10 according to the present invention shown in FIG. 1 has an optical lens 51 that has been caulked to a lens frame 52 shown in FIG. 2 and FIG. After the optical lens 51 is loaded from one side with respect to the optical axis 55 of the lens frame 52, the caulking margin portion 53 of the lens frame 52 is pressurized and deformed in a heated state, The optical lens 51 is firmly pressed against the optical surface 54 and fixed to the lens frame 52. The lens frame 52 is placed on the measuring device 10 with the crimped optical surface 54 facing up. The outer shape of the outer peripheral surface 52a, which is the lower side when the lens frame 52 is placed, is not a perfect circle with respect to the optical axis 55, but is, for example, a quadrangle as illustrated. Alternatively, a non-rotating convex part or concave part may be formed in a perfect circle shape.

  As shown in FIGS. 1 and 4, the measuring apparatus 10 includes a mounting member 12 on which a lens frame 52 is mounted, a suction port 14 that sucks an optical surface 54, and a discharge port 15 that discharges air inside the suction port. , A holding member 20 having a fitting recess 21 fitted to the fitting protrusion 17 of the suction cup 16 formed on one end surface, and a hexagonal bit 22 provided on the other end surface of the holding member 20. And a rotary type load measuring device 25 having a clamp portion 24 for gripping. The suction cup 16 is formed of a resin that does not damage the optical surface 54 even if it is strongly pressed against the optical surface 54 of the optical lens 51, such as polyacetal or techtron. Moreover, it is preferable that the size of the suction port 14 is large, and a plurality of suction cups 16 matched to the size of the optical surface 54 may be prepared.

  The rotary load measuring device 25 such as a torque meter or a torque gauge rotates the measuring device main body 26 and displays a real-time measurement value during measurement and a maximum during one measurement on the display unit 27 provided on the upper surface of the measuring device main body 26. The value is displayed. The maximum value can be reset before measurement by a reset mechanism. The holding member 20 includes a vent hole 30 communicating with the fitting recess 21 at one end side with the discharge port 15. On the other end side of the vent hole 30, a mounting bracket 32 screwed into the outer peripheral surface 31 of the holding member 20 is provided. A connection fitting 36 on the other end side of the air hose 35 whose one end is connected to the vacuum pump 34 is connected to the attachment fitting 32. The mounting member 12 is formed with a recess 38 corresponding to the outer shape of the outer peripheral surface 52a of the lens frame 52, and is supported so that the lens frame 52 mounted on the recess 38 does not rotate. In the case where the outer shape of the outer peripheral surface 52a is a perfect circle and there is no rotation prevention, the mounting member 12 may be provided with a device for fixing the lens frame 52. For example, when the optical lens 51 has a diameter of 35 mm and a thickness of 3 mm, the suction cup 16 may have a suction port 14 having a diameter of 30 mm, and the suction lens 16 adsorbs the optical lens 51. It is preferable to set the vacuum pump 34 so that the attracting force becomes 100 to 150 (N).

  The mounting member 12 is fixed to the base 41 of the support base 40. A guide column 42 is provided vertically on the base 41, and a support arm 43 is supported by the guide column 42 slidably along the guide column 42. The support arm 43 is provided with a support hole 44 centering on the extension of the optical axis 55 of the optical lens 51 mounted on the mounting member 12, so that the holding member 20 is rotatable and along the optical axis 55. It is supported so that it can move up and down.

  Next, a method for checking whether or not the optical lens 51 that has been caulked to the lens frame 52 by using the measuring apparatus 10 is caulked with an appropriate pressure will be described. In this method, a rotational force is applied to the optical lens 51 with the lens frame 52 fixed, and the static friction load immediately before the optical lens 51 starts to rotate against the caulking force of the lens frame 52 is measured. Is appropriate if it is within the range of the predetermined value, and if it is large, the optical lens 51 is likely to be distorted, so it is inappropriate. If it is small, the caulking force is weak and may be loosened during use. Is done. For example, when the appropriate value of the caulking force is 35 cN · m and the allowable range is set to ± 5 cN · m, the optical lens 51 rotates when less than 30 cN · m and when it exceeds 40 cN · m. If not, both are judged to be inappropriate.

  (First Step) As shown in FIG. 5, the lens frame 52 on which the optical lens 51 is caulked is placed on the placement member 12 fixed to the support base 40 so as not to rotate.

  (Second Step) As shown in FIG. 6, the holding member 20 is lowered, the suction port 14 of the suction cup 16 is brought into contact with the optical surface 54 of the optical lens 51, the vacuum pump 34 is turned on, and the inside of the suction port 14 is turned on. Air is sucked out from the discharge port 15, and the suction cup 16 is attracted to the optical surface 54 of the optical lens 51.

  (Third step) When the measuring instrument main body 26 of the rotary load measuring instrument 25 is turned by hand, only the measuring instrument main body 26 rotates at first and the clamp portion 24, the holding member 20 and the optical lens 51 do not rotate. The amount of force applied to the measuring instrument body 26 is displayed on the display unit 27 of the mold load measuring instrument 25. As the applied force is gradually increased, both the real-time measurement value and the maximum value displayed on the display unit 27 increase. When the applied force exceeds the caulking force that fixes the optical lens 51, the optical lens 51 rotates. When the optical lens 51 rotates, the caulking force changes from a static friction load to a dynamic friction load, so the real-time measurement value decreases rapidly, but the maximum value does not change. This maximum value is measured and recorded as the thermal caulking intensity.

  The thermal caulking strength is measured by the operations from the first step to the third step, and whether the measurement result is within the proper load range is judged as good or bad. The range of the proper load is determined by prior measurement. Determined. For the sample of the lens frame 52 in which the optical lens 51 is thermally crimped with various pressures from strong to weak, the measured value of the thermal crimping intensity by the measuring device 10 is compared with the distortion value of the optical surface 54 by the interferometer. The upper limit value of the appropriate load is determined. Based on past experience values such as impact tests and weight tests, a lower limit value for the determined upper limit value is set. The measurement is performed with the range between the upper limit value and the lower limit value being within the appropriate load range.

10 Measuring device (Measuring device for thermal caulking strength)
DESCRIPTION OF SYMBOLS 12 Mounting member 14 Adsorption port 15 Ejection port 16 Suction cup 17 Fitting convex part 20 Holding member 21 Fitting concave part 22 Hexagonal bit 24 Clamp part 25 Rotary load measuring instrument 26 Measuring instrument main body 27 Display part 30 Ventilation hole 31 Outer peripheral surface 32 Mounting bracket 34 Vacuum pump 35 Air hose 36 Connection bracket 38 Recess 40 Support base 41 Base 42 Guide post 43 Support arm 44 Support hole 51 Optical lens 52 Lens frame 53 Caulking margin portion 54 Optical surface 55 Optical axis

Claims (5)

A mounting member that supports the lens frame on which the optical lens is thermally crimped in a non-rotatable manner;
A suction cup adsorbed on the optical surface of the optical lens;
A rotational load measuring device that applies a rotational force to the holding member of the suction cup and measures a static friction load immediately before the optical lens starts to rotate;
An apparatus for measuring thermal caulking strength, comprising:   The holding member includes a vent hole formed in the suction cup for discharging the air in the suction cup to communicate with the other end side of an air hose having a vacuum pump connected to one end side. Item 1. The thermal caulking strength measuring device according to Item 1.   3. The support base to which the mounting member is fixed is provided with a support arm to which the holding member is attached so as to be rotatable about the optical axis of the optical lens and to be movable up and down. The measuring apparatus of the heat caulking intensity of description. A first step of placing the lens frame, on which the optical lens is heat crimped, on the placement member so as not to rotate;
A second step of adsorbing a suction cup on the optical surface of the optical lens;
A third step of rotating the suction cup holding member, gradually increasing the rotational force, and measuring the maximum value of the static friction load immediately before the optical lens begins to rotate against the caulking force with a rotary load measuring device. When,
A method for measuring the thermal caulking intensity, characterized in that   The holding member held by the rotary load measuring instrument is attached to a support base on which the mounting member is fixed, and is rotatable and liftable about the optical axis of the optical lens, so that the rotary load is measured. 5. The thermal caulking strength measuring method according to claim 4, wherein a rotational force is applied to the container to rotate the suction cup, and the maximum value of the static friction load is measured.

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