JP5860682B2 - Lens centering machine centering method and apparatus - Google Patents

Description

  In the present invention, the centering of a lens centering machine that processes the outer periphery with respect to the optical axis of the lens, that is, the optical axis of the lens placed on the holder holding the lens is used as the axis or rotation center of the holder. The present invention relates to a matching method and apparatus.

  The lens performs spherical processing on the front and back surfaces, and then performs peripheral processing on the basis of the optical axis determined by the processed spherical surface. An apparatus for processing the outer periphery of the lens with reference to this optical axis is called a centering machine. A general centering machine controls a holder that rotates while holding a lens, a rotating grindstone that moves closer to and away from the outer periphery of the lens held by the holder, and a moving position of the rotating grindstone in the approaching and separating direction. NC controller. Since the NC controller sets the position of the rotating grindstone with reference to the axis or rotation center of the holder, in order to perform accurate outer periphery machining, the lens to be machined as the premise is that its optical axis is the center of rotation of the holder. It is necessary to be held in exact alignment (centered).

  If the lens is a convex lens, the thickness of the central part is thicker than that of the peripheral part, and if it is a concave lens, the lens is conversely thin. As shown in FIG. 10, when the holder is rotated with the front and back surfaces of the lens lightly sandwiched between upper and lower cup-shaped holders 1b and 1a having a perfect edge 14, the lens thickness becomes the largest. Alternatively, the thinnest portion of the optical axis slides in a direction coinciding with the rotation center of the holders 1a and 1b, and the centering is automatically performed. However, a lens with a small Z value or a lens whose spherical surfaces on the front and back surfaces of the lens are close to a concentric spherical surface (thickness is nearly parallel) cannot be accurately centered by such a method.

  Therefore, as shown in FIG. 11, the lens having a small Z value rotates the holders 1a and 1b by a predetermined angle while holding the lens L lightly by the holders 1a and 1b, and the dial gauge 8 at each rotational position rotates the lens. The position of the peripheral portion of the spherical surface is measured, the eccentric direction and the eccentric amount between the center of curvature of the lens spherical surface and the axis of the holder are calculated based on the measured value, and the calculated eccentric direction is the direction of the grindstone 2 The holders 1a and 1b are rotated so as to face the lens, and then the grindstone 2 is advanced toward the lens to push and move the lens by a distance corresponding to the amount of eccentricity so that the optical axis of the lens is rotated or rotated. Centering was done by matching with the center.

  However, in the conventional means shown in FIG. 11, because of contact-type measurement using a dial gauge or the like, the lens is damaged when the measurement end of the dial gauge comes into contact with the lens and when the lens is pressed with a grindstone. There's a problem. In addition, since the contact (contact) between the grindstone and the lens cannot be detected when the lens is pushed with the grindstone, the pressing amount cannot be controlled accurately, and the surface of the grindstone (pushing surface) depends on the condition of the abrasive grains on the grindstone surface. There was a problem that there was unevenness and the pressing amount was not stable.

  An object of the present invention is to solve the above-described problems and to obtain technical means capable of quickly performing accurate centering on a lens having a small Z value without damaging the lens.

  The centering device in the lens centering machine of the present invention receives the reflected light 33 or transmitted light of the light beam 31 projected toward the lens L surface on the holder 1 and outputs the light receiving position. And a pusher (lens pusher) 4 (4a, 4b) provided separately from the rotating grindstone 2 for processing the outer periphery of the lens, and a one-dimensional or two-dimensional feed for sending the pusher toward the axis of the holder 1 Stroke control means 66 for moving the pusher 4 toward the holder center based on the measured values of the devices 42, 43, and 56 and the optical measuring instrument 3 is provided. In the case of a device equipped with a feeding device that sends the pusher 4 in a one-dimensional direction, the holder 1 is further rotated based on the measured value of the optical measuring instrument 3 so that the eccentric direction of the lens L becomes the pushing direction of the pusher 4. Phase control means 65 is provided. The phase control means 65 and the stroke control means 66 are provided as software in the NC controller 6 that controls the centering machine.

  The optical measuring instrument 3 projects the light beam 31 from the projector 32 toward the lens L on the holder above the holder 1, and receives the reflected light from the lens surface of the lens L or the transmitted light that has passed through the lens L. So as to receive light. The pusher 4 is preferably made of a material softer than the lens L, for example, a synthetic resin, at least in contact with the lens.

  The push control means 67 of the NC controller that controls the pusher feed includes various push patterns such as step feed at minute intervals, vibration feed with vibration in the feed direction, low speed feed with slow feed speed, lens L It is preferable to provide various feeding patterns such as low friction feeding to feed the cup-shaped holder 1 while supplying air pressure, and the optimum feeding pattern according to the size and curvature of the lens to be processed It is preferable to be able to select.

  The optical measuring instrument 3 is placed immediately above the holder 1 so that its measurement origin o coincides with the center of rotation of the holder 1, but the light receiving point on the light receiving element when the holder 1 is rotated once. If the deviation amount e of the light receiving point s is measured from the circular locus c of s, the eccentric amount E of the lens L including the deviation amount between the origin o of the optical measuring instrument and the rotation center a of the holder is measured. be able to.

  When the pusher 4 is brought into contact with the lens L and the lens L is pushed, the pusher 4 is fed when the optical measuring instrument 3 is pushed while monitoring the light receiving point s to move the light receiving point s to the rotation center a. May be stopped, or the pusher 4 may be moved by the eccentric amount E measured from the position where the pusher 4 contacts the lens L. The contact between the pusher 4 a and the lens L in the case of using the pusher 4 a configured to push the outer periphery of the lens can be detected by sending a signal when the light receiving point s of the optical measuring instrument 3 starts to move to the stroke control means 66.

  For example, in the case of a press-molded lens, etc., where there are irregular protrusions on the outer periphery of the lens, when measuring the eccentric direction and the eccentric amount of the lens on the holder, the lens from the center (optical axis) of the lens When the distance to the outer circumference is measured and there is a protruding portion that hinders the centering operation, it is desirable to perform roughing to remove the protruding portion with the grindstone 2 prior to the centering operation. The distance from the center of the lens to the outer periphery of the lens is measured by providing an outer periphery measuring device 7 in the centering machine.

  On the other hand, if the pusher 4b having a structure that pushes the lens in contact with the lens surface of the lens L is used, the lens can be smoothly centered without measuring the outer periphery even when there is an irregular protrusion on the outer periphery of the lens. It can be carried out. For lenses that require rough processing, rough processing may be performed after centering and before centering operation (finish grinding).

  If the pusher 4b having a structure that pushes the lens in contact with the lens surface of the lens L is used, it is possible to center the lens by moving the pusher in a two-dimensional plane. That is, when the optical measuring instrument 3 measures the direction of eccentricity and the amount of eccentricity, the pusher 4b moves the lens L in the direction opposite to the direction of eccentricity so that the optical axis of the lens L becomes the rotation center of the holder. An operation of stopping the movement of the pusher 4b when they coincide with each other, an operation of moving the pusher 4b to the lens L after moving to the measured eccentric position, and then moving the pusher 4b to the rotation center of the holder 1 Thus, the lens can be centered.

  An optical measuring instrument measures the direction (phase) in which the lens is decentered with an optical measuring instrument such as an autocollimator, and determines the phase in which the holder is decentered by rotating the spindle. By pressing the lens with a pusher to a position where no eccentricity is detected in step 1 or by pressing the push amount calculated from the eccentric amount E measured in advance with the pusher, accurate centering can be automatically performed.

  And since it is measured non-contact with an optical measuring instrument, there is no risk of damaging the lens, and centering while monitoring with an optical measuring instrument makes it possible to detect the contact between the pusher and the lens and the position of the lens after movement. Therefore, the pressing amount can be accurately controlled, and the lens can be accurately centered. In addition, because the lens is pushed with a dedicated pusher, the pusher material and the shape of the contact portion enable centering without variation without damaging the lens, and there is an effect that stable and high centering accuracy can be obtained. .

The block diagram which shows the Example of the centering machine provided with the centering apparatus of this invention Explanatory drawing showing exaggerated lens decentering and reflected light shake The figure which shows the light receiving point on the two-dimensional light receiving element of the autocollimator Explanatory drawing of outer circumference measurement performed with eccentricity measurement Schematic side view of the main part of the centering machine that performs eccentricity measurement and outer circumference measurement Flow chart showing the centering procedure of the centering machine to perform the outer circumference measurement Schematic side view of the main part of a centering machine with a pusher that pushes the lens in a two-dimensional plane 7 is a perspective view of the pusher in FIG. The figure which shows the contact of a concave lens and the pusher of FIG. Explanatory drawing showing centering means for a lens with a large Z value Explanatory drawing which shows the conventional centering apparatus with respect to a lens with small Z value

  Embodiments of the present invention will be described below with reference to examples shown in the drawings. The centering machine of the illustrated embodiment includes a main shaft 11 having an upward cup-shaped holder 1 (a member corresponding to the holder 1a in the conventional structure of FIGS. 10 and 11) at the upper end, and a ring-shaped pressing pad facing the holder 1 An upper shaft 17 having 16 at the lower end, and a rotating grindstone 2 for processing the outer periphery of the lens L sandwiched and held by the holder 1 and the pad 16 are provided. The main shaft 11 and the upper shaft 17 are arranged on the main shaft axis a in the vertical direction, and are synchronously driven by a main shaft motor 12 and a connecting shaft 15 that rotationally connects the main shaft 11 and the upper shaft 17. Therefore, the holder 1 and the pad 16 rotate synchronously about the axis a. The upper shaft 17 can be moved up and down by a lifting device (not shown). The lens L is carried onto the holder 1 in a state where the upper shaft 17 is raised, the lens is centered, and then the upper shaft 17 is lowered to lower the holder. The lens L is held in a state where the upper and lower surfaces of the lens L are sandwiched between 1 and the pad 16. The upper shaft 17 and the main shaft 11 are hollow shafts, and the hollow holes 13 of the main shaft communicate with the cup of the holder 1.

  The rotating grindstone 2 is mounted on a grindstone base 21, and is provided with a feed screw and a grindstone feed motor that drive the grindstone base 21 toward and away from the lens L in the approaching and separating directions (not shown). The spindle motor 12 and the grindstone feed motor are controlled by the NC controller 6, and the rotation angle (phase) and rotation speed of the spindle 11, and hence the holder 1, and the moving position of the grindstone table 21 are set by the NC controller 6. Is possible.

  The centering device of the present invention in the illustrated embodiment includes an autocollimator 3 disposed above the upper shaft 17, a pusher 4 (4a, 4b) mounted on the moving table 41 via a piezoelectric element 44, and a moving table. A feed screw 42 and a feed motor 43 for feeding 41 and an air pressure supply device 5 are provided.

  The autocollimator 3 receives a light projector 32 that projects a light beam 31 toward the lens L on the holder 1 through the hollow hole 18 on the upper shaft, and the reflected light 33 from the lens L is reflected by the half mirror 34 at a right angle. And a two-dimensional light receiving element 35. The light beam projected from the projector 32 irradiates the surface of the lens L as a light spot (focal point), the reflected light 33 forms an image on the light receiving surface of the light receiving element 35, and the position information is an electrical signal. Is output.

  The pusher 4 is mounted on the moving table 41 via the piezoelectric element 44, and an AC power supply 45 for vibrating the piezoelectric element 44 in the moving direction of the moving table 41 is connected to the piezoelectric element 44. The moving table 41 is connected to a feed screw 42 via a ball nut (not shown), and this feed screw is rotationally driven by a feed motor 43 that is servo-controlled by the NC controller 6.

  The NC controller 6 includes a step feed means 61 that gives a feed command and a stop command to the feed motor 43 at short time intervals, a standard feed means 62 that gives a continuous feed command at a normal speed, and a continuous feed command at a lower speed than this. Is provided with a low-speed feed means 63 for providing the above and a selection switch 64 for selecting one of these means. Further, the NC controller 6 controls an on / off switch 46 of an AC power supply 45 that vibrates the piezoelectric element 44. The air pressure supply device 5 includes a negative pressure source 51, a positive pressure source 52, pressure setting devices 53 and 54, and a switching valve 55, and a negative pressure or a positive pressure adjusted according to a lens to be processed is changed to the switching valve 55, It is supplied into the holder 1 through the rotary joint 56 and the hollow hole 13 of the main shaft 11.

  When the lens L is placed eccentrically on the holder 1, the lens tilts as shown in FIG. This inclination increases as the curvature of the lower surface of the lens in contact with the circular edge 14 of the holder 1 increases, and the direction of inclination is reversed depending on whether the surface is convex or concave. At the center of the optical axis of the lens, the lens surface is perpendicular to the optical axis, and the light projected here reflects in the incident direction, but if the lens is decentered and tilted, the reflected light deviates from the incident light, As shown in FIG. 3, the position of the light receiving point s on the light receiving element 35 is shifted. From the deviation e, the inclination of the lens L can be measured, and the eccentric amount E of the lens L can be measured from the inclination and the curvature of the lower surface of the lens.

  When the holder 1 is rotated to draw a circular locus c at the light receiving point s, and the eccentric direction and the eccentric amount are measured with the center (rotation center of the holder) a of the circular locus as the origin, the light receiving surface of the autocollimator 3 is obtained. Even if the origin o is deviated from the rotation center of the holder 1, the accurate eccentric direction and the eccentric amount can be measured.

  The NC controller 6 includes an optical axis of the lens L from the center of rotation of the holder 1 based on the detection signal of the autocollimator 3 and the previously inputted unevenness of the lower surface of the lens (the eccentric direction is 180 degrees opposite). , The phase control means 65 for controlling the rotation angle of the spindle motor 12 so that the eccentric direction faces the moving direction of the pusher 4, and the feed motor 43 based on the detection signal of the autocollimator 3. Stroke control means 66 is provided for controlling the rotation angle.

  In the above-described centering device, when the lens L is loaded onto the holder 1 with the upper shaft 17 moved upward, the autocollimator 3 irradiates the light beam 31 onto the lens L, and the reflected light is 2 The main shaft 11 is slowly rotated while being received by the three-dimensional light receiving element 35, and a circular locus c is drawn at the light receiving point s on the light receiving element 35, and the eccentricity of the lens L with respect to the rotation center of the holder 1 from the radius e of the circle. The amount E is measured, and the eccentric direction is measured from the relative positional relationship between the light receiving point s and the center a of the circle when the holder 1 is stopped. The NC controller 6 gives a rotation command to the main shaft motor 12 so that the detected eccentric direction faces the moving direction of the pusher 4.

  Next, the NC controller drives the feed motor 43 to move the lens L on the holder 1 with the pusher 4 so that the optical axis of the lens L and the rotation center of the holder 1 coincide with each other, thereby centering the lens. Do. When the pusher 4 is a pusher 4a (FIGS. 1 and 5) configured to push the outer periphery of the lens, a forward command is given to the moving base 41, and a movement start signal of the light receiving point s is received from the autocollimator 3 during this forward movement. When this happens, a measurement start command is given to the stroke control means 66. The stroke control means 66 stops the feed motor 43 at a position where the pusher 4a has been advanced by an eccentric amount already measured from the position of the pusher 4a when the measurement start command is given.

  When the pusher 4a moves forward, the selection switch 64 is switched according to the size and curvature of the lens L, so that the push operation pattern can be selected from step feed, standard feed, and low speed feed. Furthermore, the vibration feed can be selected by turning on the switch 46 of the AC power supply 45 in each feed pattern. Step feed and vibration feed are effective in preventing the lens L from moving beyond its stop position due to the so-called stick-slip phenomenon.

  The lens L carried in on the holder 1 is measured and centered while being lightly adsorbed by the negative pressure supplied to the holder 1. This is to prevent the lens from moving during the measurement, and to prevent the lens from slipping lightly on the holder without damaging the lens when pressed by the pusher 4a, and not to slip too much due to the pressed inertia. Accordingly, negative pressure is supplied to the holder 1 from the negative pressure source 51 during normal lens centering. In the illustrated embodiment, when the lens is heavy, the switching valve 55 is switched to supply the positive pressure from the positive pressure source 52 to the holder 1 to reduce the load on the lens acting on the holder 1. The lens L can be pushed in a state where the friction load is reduced.

  When pushing the lens L with the pusher 4a, the lens L may move in a direction deviating from the forward direction of the pusher 4a during pushing, and the lens may move excessively due to inertia. Therefore, after the pushing operation is finished, the optical measuring instrument 3 confirms the eccentricity of the lens L, and if it is within a predetermined error range (threshold), the outer periphery machining is started. The centering operation is repeated by measuring the eccentric direction and the eccentric amount.

  When the centering of the lens is completed as described above, the upper shaft 17 is moved downward to hold the lens L by the holder 1 and the pad 16, and the main shaft 11 and the upper shaft 17 are rotated synchronously by the main shaft motor 12. Is rotated around the centered optical axis. Then, by rotating the rotating grindstone 2 and moving the grindstone base 21 forward so that the outer peripheral shape of the lens becomes a predetermined shape, the outer peripheral processing based on the optical axis of the lens L is performed.

  In a press-molded lens, the material pressed by the upper and lower molds may protrude from between the molds at the periphery of the lens, and the outer peripheral shape of the lens may become distorted. When the pusher 4a moves forward toward the lens L to push the lens, the pusher 4a rapidly approaches the lens and then decelerates to a predetermined pushing speed and pushes the lens L in order to shorten the processing cycle. If there is a protruding portion made of a material protruding from between the molds around the lens L, the pusher 4a may come into contact with the protruding portion and move the lens greatly during rapid approach. Further, there is a possibility that the pusher 4a hits the edge of the end portion of the projecting portion and the lens moves in a direction deviated from the pushing direction. Further, when the lens is carried on the holder 1 on the basis of the outer periphery, the lens on the holder may be greatly decentered.

  Therefore, for such a lens, it is desirable to confirm the outer peripheral shape of the lens before centering (original peripheral processing) and to perform rough processing (roughing) to remove partial protrusions. . The outer peripheral shape of the lens is confirmed by a non-contact or contact-type outer peripheral measuring instrument such as a camera or an electronic micrometer when the lens L is rotated once to measure the eccentric amount and the eccentric direction of the lens optical axis. 7 can be confirmed by detecting the outer peripheral position of the lens.

  FIG. 4 shows the center (optical axis) p of the lens placed eccentrically on the holder, the rotation center a of the lens (holder 1), and the rotation center a measured by the outer circumference measuring instrument 7 to the lens outer periphery. In the figure showing the relationship between the distance d and the distance r from the lens center p to the outer periphery, the lens eccentricity E is measured by the autocollimator 3, so that the lens is rotated once using d and E. The distance r at each rotational angle θ position can be obtained by calculation, and the region where r exceeds the threshold value may be subjected to roughing to cut the outer periphery.

  FIG. 5 is a diagram showing an example in which the pusher 4 and the electronic micrometer 7 are mounted on the moving table 41 via a lifting table 48 that moves up and down with a short stroke, for example, by a cylinder 47 or the like. When the holder 1 is rotated once and the autocollimator 3 detects the eccentric direction and the eccentricity of the optical axis of the lens, the electronic micrometer 7 is moved down by moving the lifting table 48 and moving the moving table 41 forward. The detection end of the lens is brought into contact with the outer periphery of the lens L, and the outer peripheral shape of the lens L is measured.

  If the outer peripheral shape is measured, the distance from the lens outer periphery to the pusher 4a when the eccentric direction of the lens L is directed to the pusher 4a can be known, so that the tip of the pusher 4a reaches the nearest position where it contacts the outer periphery of the lens L. By making the pusher 4a approach rapidly, the machining cycle can be shortened.

  FIG. 6 is a flowchart showing the procedure. When the lens is carried onto the holder 1, a negative pressure is supplied to the holder to attract the lens. Next, the lift 48 is lowered and the electronic micrometer 7 is opposed to the outer periphery of the lens (FIG. 5). The moving table 41 is advanced while monitoring the output of the electronic micrometer 7. When the electronic micrometer 7 comes into contact with the outer periphery of the lens, the output of the electronic micrometer 7 is shaken. Therefore, after detecting the contact, the movable table 41 is further advanced by a set amount and stopped. This set amount is the maximum projection amount of the lens outer periphery that is expected.

  In this state, the holder 1 is rotated once while storing the measurement value of the electronic micrometer 7 at each rotational position. Due to this rotation, the amount of eccentricity and the direction of eccentricity of the lens on the holder are detected by the autocollimator 3, so the dimension r in FIG. 4 at each rotational position of the lens is calculated, and r exceeds the threshold value. Check if there is a range. In the meantime, the elevator 48 is raised so that the pusher 4 faces the lens.

  If there is an area where the dimension r exceeds the threshold value, the moving table 41 is retracted, the upper shaft 17 is lowered and the lens is clamped, and then the area where r exceeds the threshold value is directed toward the grindstone 2. By the rough machining by the advancement of the grindstone table 21 to the predetermined position and the rotation of the holder 1 within the range, the protrusion of the region where r exceeds the threshold value is deleted, and the upper shaft 17 is raised. Release the lens clamp.

  Next, the eccentric direction detected by the autocollimator is directed to the pusher, the dimension d in FIG. 4 in the eccentric direction and the distance from the pusher standby position to the pusher tip and the lens outer periphery are calculated, and the pusher tip moves to the lens outer periphery. The moving table 41 is rapidly advanced to a position immediately before the contact. Then, after the forward speed of the moving table 41 is switched to a low speed and the contact between the pusher 4a and the lens L is detected, the moving table 41 is further advanced by the detected eccentric amount to center the lens. Then, after retracting the movable table 41 and lowering the upper shaft to clamp the lens, the centering process is started.

  In this way, the outer circumference is measured simultaneously with the detection of the optical axis of the lens, and before the centering process with the grindstone 2 for the necessary lens, the outer circumference of the lens is roughly processed with the grindstone, and the lens that is in contact with the lens is in the nearest position. If the pusher 4a is rapidly advanced to the position, it is possible to efficiently and accurately perform the centering process for the lens group having a variation in the outer peripheral shape.

  The above procedure is an example of a procedure for centering a lens having a protruding portion on the outer periphery by using the pusher 4a having a structure for centering the lens by pushing the outer periphery. If the pusher 4b having the structure is used, the lens can be centered without measuring the outer periphery even if the lens has a protrusion on the outer periphery. FIGS. 7 to 9 are diagrams showing an example of an apparatus that pushes the lens in contact with the lens surface, FIG. 7 is a side view of the main part of the apparatus, FIG. 8 is a perspective view of the pusher, and FIG. It is the figure which showed the contact state of the pusher 4b with respect to the lens which has become. In addition, the contact state of the pusher 4b with respect to the lens whose upper surface is a convex surface is shown by the imaginary line in FIG.

  The pusher 4b shown in the figure has a structure in which a cylindrical portion 55 projecting downward is provided on the plate material 54, and a through hole having the same shape as the hollow hole of the cylindrical portion is also provided in the plate material 54, so that the light beam and reflection of the optical measuring instrument 3 It allows light to pass through. The pusher 4b is mounted on an XY moving table 56 that moves in a two-dimensional plane in the horizontal direction of FIG.

  When the optical measuring instrument 3 measures the eccentric direction and the eccentric amount of the lens L on the holder 1 in the same manner as described above, the elevator 48 is raised to move the XY moving table 56 in the horizontal direction and the direction perpendicular to the drawing. By moving, the pusher 4b is moved to a position where the center of the cylindrical portion of the pusher 4b coincides with the measured optical axis of the pusher 4b, the elevator 48 is lowered, and the lower edge of the cylindrical portion 55 is pushed onto the upper surface of the lens L. Touch.

  In this state, the center of the lens L is centered by moving the XY moving table 56 in a two-dimensional plane in the horizontal direction of the drawing and the direction perpendicular to the paper surface and moving the center of the cylindrical portion of the pusher 4b to the rotation center of the holder 1. Then, the lens centering operation is completed by raising the elevator 48 and moving the XY moving table 56 backward. For example, the cylindrical portion 55 of the pusher is made of a material having a friction coefficient larger than that of the holder 1, or a positive pressure is supplied to the holder 1 to reduce the friction between the lens and the holder 1, thereby pressing against the upper surface of the lens. The lens on the holder 1 can be slid and moved by the frictional force of the cylindrical portion 55.

  Thereafter, the upper shaft 17 is lowered to hold the lens L, and the centering is performed by grinding the outer periphery of the lens with the grindstone 2 while rotating the lens L, but the grindstone 2 is advanced to a preset position. If the lens is rotated and rough processing is performed, and then the cutting amount of the grindstone 2 is reduced and the centering is performed by finish grinding, the centering of the lens having a protruding portion on the outer periphery can be performed quickly. it can.

  As described above, if a pusher having a structure in which the lens is pressed while being in contact with the lens surface, accurate centering can be performed for any lens having an outer peripheral shape. Since it can move in the dimension plane, there is no need to rotate the holder to align the lens pushing direction with the pusher moving direction, the control procedure is simplified, and the pusher can be moved at a high speed. Therefore, cycle time can be shortened.

DESCRIPTION OF SYMBOLS 1 Holder 2 Rotary grindstone 3 Optical measuring instrument 4 (4a, 4b) Pusher 6 NC controller 7 Perimeter measuring instrument 31 Light beam 32 Projector 33 Reflected light 35 Light receiving element 42 Feed screw 43 Feed motor 48 Lifting table 56 XY moving table 65 Phase Control means 66 Stroke control means 67 Push control means a Center of rotation c Circular locus o Origin s Light receiving point L Lens

Claims (10)

In a lens centering device in a lens centering machine equipped with a holder that rotates about a vertical axis, the reflected light or transmitted light of the light beam projected toward the lens surface on the holder is received and the light receiving position is output. An optical measuring instrument, a pusher whose contact end is made of a material softer than the lens, a feed device that moves the pusher toward the rotation center of the holder, and an NC controller. Comprises stroke control means for moving the pusher toward the rotation center of the holder based on the measurement value of the optical measuring instrument, and the NC controller is selected from a plurality of pushing operations including step feed or vibration feed. A lens centering device in a lens centering machine , wherein the pusher is moved by a pushing operation.   The pusher is a pusher that pushes the lens by an advance operation in a one-dimensional direction, and the NC controller holds the holder so that the eccentric direction of the lens is directed to the movement direction of the pusher based on the measurement value of the optical measuring instrument. The lens centering device according to claim 1, further comprising phase control means for rotating the lens.   The lens centering device according to claim 2, further comprising an outer circumference measuring device that measures a distance from a rotation center of the holder to an outer circumference of the lens on the holder.   The lens centering device according to claim 1, wherein the pusher is a pusher that pushes the lens by a movement operation in a two-dimensional plane. The optical measuring instrument reflects the light beam projected from above the holder as a light spot on the lens surface, forms an image of the reflected light on the two-dimensional light receiving surface, and deflects the reflected light with respect to the projected light at the imaging position. The centering device according to claim 1, 2, 3, or 4 , wherein the center direction and the amount of eccentricity are detected . The centering device according to claim 1, 2, 3 or 4 is mounted on a lens centering machine, and a circular locus is drawn on the light receiving surface of the optical measuring instrument by rotating the holder with the lens mounted on the holder. Measure the eccentric direction of the lens from the center of the circular locus and the position of the light receiving point when the holder is stopped, measure the eccentric amount of the lens from the diameter of the circular locus, and move based on the measured value A method of centering a lens in a lens centering machine, wherein the lens is centered on a holder by pushing the lens with a pusher. The centering device according to claim 2 or 3 is mounted on a lens centering machine, the lens is mounted on the holder, and after measuring the decentering direction and decentering amount of the lens on the holder with an optical measuring instrument, the holder is decentered. When the lens is rotated in the direction of the core and then the pusher is advanced toward the lens by the amount of eccentricity measured and the lens is pushed, the light receiving point is monitored by the optical measuring instrument, and the light receiving point starts to move on the light receiving surface. A lens centering method in a lens centering machine , wherein the pusher stroke is controlled so that the amount of movement of the pusher after that point becomes the measured eccentric amount, assuming that the pusher and the lens are in contact with each other . The centering device according to claim 1, 2, 3, or 4 is mounted on a lens centering machine, the lens is mounted on the holder, the eccentric direction of the lens on the holder is measured with an optical measuring instrument, and the eccentric direction When the lens is pushed with a pusher , the optical receiver monitors the light receiving point, and stops the pusher movement when the light receiving point on the light receiving surface matches the rotation center of the holder on the light receiving surface. Lens centering method in the machine. The centering device according to claim 3 is mounted on a lens centering machine, the lens is mounted on the holder, the decentering direction and the decentering amount of the lens on the holder are measured by an optical measuring instrument, and the holder is measured by an outer peripheral measuring instrument. Measure the distance from the axis of the lens to the lens outer periphery, and when the distance exceeding the preset threshold is measured, rough processing of the lens outer periphery is performed, and then the eccentric direction of the holder measured by the optical measuring instrument A lens centering method in the lens centering machine, in which the pusher is advanced toward the lens and then the lens is pushed and moved . The centering device according to claim 4 is mounted on a lens centering machine, the lens is mounted on the holder, the decentering direction and the decentering amount of the lens on the holder are measured with an optical measuring instrument, and the center of rotation of the holder is measured. A lens centering method in a lens centering machine , wherein the pusher moved to the measured eccentric position is brought into contact with the lens, and then the pusher is moved to the rotation center of the holder .

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