JP2005230985A - Optical lens blocking device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical lens blocking device equipped with a simple centering mechanism capable of moving an optical lens with different edge thickness positively into a predetermined blocking position without needing a blocking ring. <P>SOLUTION: A centering mechanism 13 is provided around a placing table 11 on which a lens blank 1 is installed, to allow the geometric center of the lens blank 1 to coincide with the center of the placing table 1. The centering mechanism 13 is provided with three clamping pins 31 for pressing the outer peripheral surface of the lens blank 1. The placing table 11 on which the lens blank 1 is placed, is pushed up by an air cylinder 12 when blocking, and the concave surface 1a side outer peripheral edge of the lens blank 1 is pressed to the lower faces of locking parts 31A of the clamping pins 31 to position the concave surface 1a into a blocking position H<SB>2</SB>. In this state, a fixture 2 is lowered by a predetermined quantity to press and solidify wax dropped on the concave surface 1a of the lens blank 1. The lens blank 1 is thereby blocked by the fixture 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical lens blocking device.

  Conventionally, when a spectacle lens is manufactured from a circular lens base material (hereinafter referred to as “lens blanks”) whose convex surface is not processed, the lens is controlled by a numerically controlled grinding machine (for example, a general-purpose polishing apparatus TORO-X2SL manufactured by LOH). By cutting or grinding the convex surface of the blanks into a predetermined surface shape, the thickness is made slightly thicker than the finished dimensions that allow for sanding allowance and polishing allowance, and the convex surface is polished to a predetermined curved surface by a polishing device I'm making it.

  In the cutting process and polishing process of lens blanks, the non-polished surface of the lens blanks is fixed to a lens holder (hereinafter referred to as “Yato”) with a bonding agent, and the Yato is attached to a polishing apparatus (for example, Patent Document 1). reference). Here, fixing lens blanks to a Yatoi via a bonding agent is called blocking or block. Moreover, as such a blocking device, for example, a device called a layout blocker manufactured by LOH is known.

  As a bonding agent used for blocking lens blanks, a low melting point alloy or wax is generally used. When blocking the lens blanks, as shown in FIG. 13, the lens blanks 1 are arranged above the Yatoi 2 via the blocking ring 3 and melted in a space surrounded by the lens blanks 1, Yatoi 2 and the blocking ring 3. The lens blanks 1 are fixed to the Yatoi 2 by pouring the bonding agent 4 and cooling and solidifying (see, for example, Patent Document 2). In addition, the code | symbol 5 in a figure is a base.

When the lens blanks 1 are blocked by the yatoy 2, it is necessary to accurately match the centers of the lens blanks 1 and the yatoy 2. For this reason, the lens blanks 1 are clamped and centered (for example, refer to Patent Documents 3 and 4). Also, various types of yatoi 2 and blocking ring 3 are prepared corresponding to the type of lens blanks 1, and the bonding agent 4 is selected by selecting and using the yatoy 2 and blocking ring 3 corresponding to the lens blanks 1 at the time of blocking. The center wall thickness of the sheet is set to a predetermined thickness (see, for example, Patent Document 2).
US Pat. No. 5,421,770 Japanese Patent Application No. 2002-138105 JP 09-290340 A JP-A-11-325828

  The circular centering device described in Japanese Patent Application Laid-Open No. 09-290340 is a device that performs mechanical centering based on the outer periphery of a circular body (lens), and has a circular cam surface on the outer periphery. A guide portion protruding from one side of the base member, three rollers disposed equiangularly on the outer periphery of the cam surface of the guide portion, and the rollers disposed outside the guide portion. A rotatable ring member to be supported, three lever members having a fulcrum at an equiangular position on the outer side of the ring member in the base member and gripping the outer periphery of the circular body at the tip, and gripping of these lever members Lever member urging means that presses each portion against each roller, and ring member urging that urges the ring member so that the gripping portion of the lever member rotates inwardly via the roller. Means and said Gripper of the lever member a ring member and a gripper opening means for positioning a position away from said circular body.

  JP-A-11-325828 relates to a measuring method and apparatus for obtaining the center position of a concave surface and the center position of the outer shape of an optical component in an engineering member having a concave surface such as a concave lens or concave mirror, and the peripheral edge of the concave surface of the optical component. A plane is formed by cutting the coordinates of at least three points on a circle surrounded by the plane using a differential interference microscope and a distance measuring device that measures the amount of movement of the moving table. The center position is calculated, and the calculated center position is determined as the center position of the concave surface.

  However, the circular centering device described in Japanese Patent Application Laid-Open No. 09-290340 requires a guide portion and a roller having a cam surface, so that the structure is complicated, the number of parts is large, and the manufacturing cost is high. There is a problem of becoming high, and it is not practical.

  The concave center position measuring method, eccentricity measuring method and measuring apparatus described in Japanese Patent Application Laid-Open No. 11-325828 are an X moving table and a Y moving table that move the moving table on which the optical components are placed in directions orthogonal to each other. It is composed of a moving table, and the amount of movement of these moving tables is measured by a distance measuring device, and a signal corresponding to the amount of movement of each moving table transmitted from the distance measuring device is processed by an arithmetic device, Since the center position and the eccentric direction of the optical component are obtained, there is a problem that the apparatus itself becomes expensive.

  Therefore, development of an inexpensive centering mechanism is desired.

  When blocking lens blanks, the optical surface is blocked by the thickness of the outer peripheral surface (edge thickness) when the lens blanks are placed on a base or the like with the blocked surface (blocked surface) facing up. Therefore, the blocking ring 3 corresponding to the thickness of the lens blank 1 is required. For this reason, there are many types of the blocking ring 3, and there has been a problem that the storage and management thereof become complicated.

The present invention has been made in order to solve the above-described conventional problems. The object of the present invention is to eliminate the need for a blocking ring and to reliably move optical lenses having different edge thicknesses to predetermined block positions. It is an object of the present invention to provide a blocking device for an optical lens that can be made to operate.
Another object of the present invention is to provide an optical lens blocking device including a simple centering device.

  In order to achieve the above object, the first invention is an optical lens for fixing the optical lens to the lens holder by interposing a molten bonding agent between the optical lens and the lens holder to be cooled and solidified. In the blocking apparatus, a mounting table on which the optical lens is mounted with its concave surface up, a centering mechanism for matching the geometric center of the optical lens with the center of the mounting table, and the concave surface of the optical lens on the concave surface A dropping device for dropping the bonding agent and a moving device for moving the optical lens to a block position of the lens holder are provided.

  In a second aspect based on the first aspect, the centering mechanism is provided with a plurality of pins that are provided around the mounting table so as to be movable in a radial direction and a circumferential direction of the mounting table and press the edge surface of the optical lens. And a locking portion for locking the outer peripheral edge of the concave side of the optical lens at the block position is provided at the upper end of these pins.

  In a third aspect based on the first aspect, the centering mechanism includes a clamp base that surrounds the mounting table, a rotation base that is rotatably incorporated in the clamp base, and a drive device that rotates the rotation base. A plurality of clamp plates rotatably provided on a fixed shaft projecting on the clamp base, and slidably inserted in elongated holes provided on the respective clamp plates. And a plurality of pins that are erected on the tip of each clamp plate and press the edge surface of the optical lens.

  According to a fourth invention, in any one of the first, second, and third inventions, a drive device is provided that raises the mounting table and moves the optical lens to the block position along the pin. The table is swingably supported by a swing mechanism.

In the first aspect of the invention, since the moving device for moving the optical lens to the block position is provided, various optical lenses having different edge thicknesses can be reliably moved to the block position, and blocking by the lens holder is possible. To.
Moreover, since the bonding agent is dropped on the concave lens surface by the dropping means, it is not necessary to use a blocking ring, and the supply amount of the bonding agent can be accurately controlled.

  In the second and third inventions, a simple centering mechanism with a small number of parts can be obtained.

  In the fourth invention, since the mounting table is tilted by the swing mechanism, the concave surface side can be maintained in a horizontal state even with optical lenses having different edge thicknesses in the circumferential direction. It is possible to prevent the agent from flowing down.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.
FIG. 1 is a view showing a state in which lens blanks are blocked by Yatoi, FIG. 2 is an external perspective view of a main part of a blocking device according to the present invention, FIG. 3 is a perspective view of a centering mechanism portion of the device, and FIG. FIG. 5 is a view showing a state in which the lens blank is locked at the block position, FIG. 6 is a view showing a dropping device, FIG. 7 is a view showing the inside of the gear pump, and FIG. 8 is a dropping amount of wax. It is a figure which shows the relationship between a pulse number.

  In FIG. 1, 1 is a lens blank, 2 is a yatoi as a lens holder, 4 is a bonding agent for integrally bonding the lens blanks 1 and 2 and 6 is a protective film. The lens blanks 1 are plastic-finished semi-finished lenses such as diethylene glycol bisallyl carbonate resin (refractive index = 1.50), urethane resin, epithio resin (refractive index = 1.55 to 1.75), and the like. It has been produced. The concave surface 1 a of the lens blank 1 is processed to a predetermined radius of curvature, is finished to a predetermined optical surface, and is a surface blocked by the yatoy 2. On the other hand, the convex surface 1b is a surface which is polished by a polishing machine after the lens blanks 1 are blocked by the blocking device according to the present invention. As types of the lens blanks 1, there are four types of outer diameters (LDb) of 80, 75, 70, and 65 mm, for example, when classified by size.

  The yatoy 2 that blocks the lens blank 1 is integrated with a disc portion 2A (aluminum) whose maximum outer diameter (YDh) is smaller than the outer diameter (LDb) of the lens blank 1, and the back center of the disc portion 2A. It is comprised by the cyclic | annular protrusion part 2B (SUS303) which protruded. The front surface 2a of the disc portion 2A is a surface that blocks the lens blank 1 (hereinafter referred to as a blocking surface) and is a convex surface having a curvature radius (Ch) that is substantially the same as or approximate to the curvature radius (R) of the concave surface 1a of the lens blank 1. A thin oxide film is formed on the surface by alumite treatment. In the present embodiment, the blocking surface 2a is colored using the pores of the oxide film made of anodized. The back surface 2b of the disc portion 2A forms a reference surface when the Yatoi 2 is mounted on a polishing device or a cutting device, and a fitting portion where the protruding portion 2B is fitted to a chuck portion of the polishing device or the cutting device. Forming. A plurality of types of such yatoys 2 are prepared corresponding to the types of lens blanks 1. When the blocking surface 2a of the yatoy 2 is substantially matched with the shape of the concave surface 1a of the lens blank 1, the distance between the concave surface 1a of the lens blank 1 and the blocking surface 2a can be made substantially constant over the entire surface. Can be used in an appropriate amount, and the cooling time of the bonding agent 4 can be shortened.

  Table 1 below shows the types of Yatoi 2. There are 16 types of Yatoi 2, which have a combination of different outer diameters and different curvature radii of the blocking surface 2a. The lens is the same or approximate to the curvature radius R and outer diameter LDb of the concave surface 1a of the lens blanks 1. A yatoy 2 having a shape corresponding to the blanks 1 is selected and used. As the shape of the Yatoi 2, four types (80, 75, 70, 65 mm) are used for the outer diameter, and five types (R162, R105, R76, R61, R55) are used for the radius of curvature of the blocking surface 2a.

As the bonding agent 4, wax or a low melting point alloy (for example, Bi, Pb, Sn, Cd, In alloy, melting point 47 ° C.) is used, but in this embodiment, a highly viscous wax (preferable use) An example using a temperature of 70 to 80 ° C. will be described. Wax 4 is a blend mainly composed of polyethylene wax, the main component of which is hydrocarbon (C _n H _2n ). The physical properties of the wax 4 are a softening point of 57 ° C., a flash point of 300 ° C., a density of 0.92 g / cm ² (25 ° C.), a viscosity of 330 mPa · s (100 ° C.) and is insoluble in water.

  When the lens blanks 1 are blocked by the yatoy 2, the lens blanks 1 are usually blocked via the protective film 6. The protective film 6 is used to prevent the concave surface 1a from being scratched during polishing and to facilitate the removal of the wax 4, and is composed of a three-layer structure of a surface layer, an intermediate layer, and an adhesive layer. The surface layer and the intermediate layer are made of polyethylene, and the adhesive layer is made of polyolefin. The thickness of each layer is about 10 μm for the surface layer, 85 μm for the intermediate layer, and about 25 μm for the adhesive layer. The physical properties of the protective film 6 are a film-like solid at room temperature, a melting point of 110 to 130 ° C., and a specific gravity of 0.9 to 1.0. Another example of the protective film 6 may be a two-layer structure of a base material layer made of polyethylene and an adhesive layer made of polyolefin. Its physical properties are a film-like solid at room temperature, a melting point of 110 to 130 ° C., and a specific gravity of 0.9 to 1.0.

In FIG. 2, a blocking device generally indicated by reference numeral 10 indicates a device that blocks the lens blanks 1 with a yatoy 2, and the blocking device 10 is mounted on the lens blanks 1 with the concave surface 1a facing upward. A stage 11, a moving device 12 (FIG. 4) for moving the lens blank 1 from the centering position H ₁ to the block position H ₂ (FIG. 5), a centering mechanism 13 for centering the lens blank 1, and wax on the lens blank 1 4 is provided with a dropping device 14 for dropping 4, an interval setting mechanism 15 for setting the interval between the lens blanks 1 and the yatoy 2 to a predetermined interval at the time of blocking, a control unit (not shown) for controlling the entire device, and the like.

  In FIG. 4, the mounting table 11 is attached to the upper end of a support shaft 17 that can move up and down, and a pad 19 is mounted on the upper surface via an O-ring 18. The pad 19 is used to facilitate the movement of the lens blank 1 during centering. The mounting table 11 is attached to the support shaft 17 so as to be swingable in all directions (free to swing) with respect to the support shaft 17 so as to be compatible with various lens blanks 1. For this reason, even if the lens blanks 1 are extremely prismatic and have different edge thicknesses in the circumferential direction, the mounting table 11 is tilted with respect to the horizontal plane by the swing mechanism 20, so that three clamp pins described later are provided. The concave surface of the lens blank 1 can be held horizontally by abutting the outer peripheral edge of the concave surface of the lens blank 1 against the lower surface of the locking portion 31. The mounting table 11 is swingably attached to the upper end of the support shaft 17 and is urged downward by a plurality of tension coil springs 21 arranged around the support shaft 17.

The moving device 12 for moving the lens blank 1 from the centering position H ₁ to the block position H ₂ is composed of an air cylinder with a speed controller 24 mounted on the lower surface of the slide plate 22 through a bracket 23 with an upper end. The portion extends upward through an insertion hole 25 provided in the slide plate 22, and is configured to move the support shaft 17 up and down by an operating rod 26. The slide plate 22 is configured to reciprocate between the block position H ₂ and the dropping position H ₃ (FIG. 2) of the wax 4 by a driving device such as a cylinder (not shown). The centering position H ₁ is a position where the lens blanks 1 are centered by the centering mechanism 13, which is a position on the right side of the dropping device 14 and in front of the interval setting mechanism 15 in FIG. 11 is the upper surface position. The block position H ₂ is a position above the centering position H _{1 and is} a position where the outer peripheral edge on the concave surface side of the lens blank 1 is locked by the locking portion 31 A of the clamp pin 31. Reason for providing the block position H ₂ above the centering position H _1, even various lens blank 1 edge thickness 1c are different, positioning the peripheral edge of the concave 1a during block at a predetermined height position This is to make it possible. The dropping position H ₃ is a position at which the wax 4 is dropped onto the concave surface 1 a of the lens blank 1 by the dropping device 14 and is at the left side of the block position H ₂ and at the same height position.

  3 and 4, the centering mechanism 13 performs centering of the lens blank 1, and makes the geometric center coincide with the center of the mounting table 11. Three centering mechanisms 13 are arranged around the mounting table 11. The clamp plate 30 and the pins (hereinafter referred to as clamp pins) 31 erected on each clamp plate 30 are provided. The clamp plate 30 is pivotally supported by a fixed shaft 34 whose base end is erected on the upper surface of the clamp base 33 so as to be rotatable in the radial direction of the clamp base 33, and the clamp pin 31 is erected at the distal end portion. .

All the clamp pins 31 have the same length, and a locking portion 31A is integrally projected at the upper end as shown in FIG. The locking portion 31A is formed in a bowl shape, and the lower surface thereof receives the outer peripheral edge of the lens blank 1 on the concave surface 1a side and defines the rising limit of the lens blank 1, and the height position of the lower surface of the locking portion 31A is Yaito. 2 is a block position H ₂ when the lens blank 1 is blocked by ₂ .

  The clamp base 33 is formed in a cylindrical shape and is fixed on a plurality of support columns 35 projecting from the center of the upper surface of the slide plate 22, and a rotation base 36 is rotatably incorporated inside through a bearing 37. ing. Three fixed shafts 34 that pivotally support the base end portion of each clamp plate 30 are provided at equal intervals in the circumferential direction of the clamp base 30.

  The rotation base 36 is formed in a cylindrical body having a through hole 38 through which the support shaft 17 of the mounting table 11 passes, and is configured to reciprocate by a predetermined angle by an air cylinder 39 installed on the slide plate 22. ing. The air cylinder 39 is a direct acting type air cylinder, and is configured to convert the linear reciprocating motion of the rod 40 into a circular motion and transmit the circular motion to the rotary base 36 via the shaft 41. Yes.

  Three moving shafts 44 are erected on the upper surface of the rotating base 36 at equal intervals in the circumferential direction, and these moving shafts 44 have a long hole 43 formed at the center of each clamp plate 30. It slidably penetrates and protrudes upward. Therefore, when the rotation base 36 is rotated in the direction of arrow A in FIG. 3 by the air cylinder 39 when the lens blanks 1 are centered, each clamp plate 30 is the same in the closing direction (arrow B direction) with the fixed shaft 34 as the rotation center. The lens blanks 1 are centered by the clamp pin 31 by rotating the angle. That is, when the rotation base 36 is rotated in the direction of arrow A, the moving shaft 44 is moved in the direction away from the fixed shaft 34 in the long hole 43, so that the clamp plate 30 is rotated in the direction of arrow B. As a result, the clamp pin 31 also moves in the direction of the arrow B and hits the edge surface 1c of the lens blank 1. Therefore, when the geometric center is decentered from the center of the mounting table 11, the lens blank 1 is moved in the direction opposite to the decentering direction. The geometrical center of the lens blank 1 is made to coincide with the center of the mounting table 11. On the contrary, when the rotation base 36 is rotated in the direction of arrow C, each clamp plate 30 is rotated by the same angle in the opening direction (arrow D direction), and the clamp pin 31 is separated from the lens blank 1.

  Three positioning blocks 50 are further provided on the upper surface of the clamp base 30 so as to be positioned in front of the clamp plates 30 and substantially orthogonal to the clamp plates 30. The positioning block 50 is formed in an inverted L shape including a horizontal arm portion 50A and a leg portion 50B. The horizontal arm portion 50A extends in the center direction of the rotation base 36 and is located in front of the corresponding clamp plate 30. The leg portion 50 </ b> B is fixed to the upper surface of the clamp base 30. A bearing 51 (FIG. 3) interposed between the rotation base 36 and the horizontal arm portion 50 </ b> A of the positioning block 50 is attached to the distal end portion of each clamp plate 30. The bearing 51 is configured so that the clamp plate 30 is supported at both ends together with the fixed shaft 34, and when the lens blank 1 is lifted together with the mounting table 11 and pressed against the lower surface of the engaging portion 31A of the clamp pin 31, the horizontal arm of the positioning block 50 is obtained. The clamp plate 30 is pressed against the lower surface of the portion 50A, thereby preventing the clamp plate 30 from being lifted.

  In FIG. 6, the dropping device 14 that drops the wax 4 on the concave surface 1 a of the lens blank 1 includes a tank 61 that stores the wax 4, a nozzle 62 that drops the wax 4 on the lens blank 1, and the tank 61 and the nozzle. 62, a pipe 63 that intermittently feeds the wax 4 from the tank 61, a stepping motor 65 that drives the pump 64, a drip valve 66 that opens and closes the nozzle 62, the tank 61 and the pipe The heaters 67 and 68 for heating the heater 63 and the air cylinder 69 with a speed controller for opening and closing the dropping valve 66 are included.

  The wax 4 is put into the tank 61 in a solid state and is heated and melted by the heater 67. The temperature in the tank 61 is controlled by a temperature regulator. The temperature controller is automatically turned on and off at the time set by the timer switch. The heater 61 of the tank 61 takes 2 hours to heat and melt the wax 4 from a solid state to 70 ° C. However, by preliminarily dissolving the wax 4 by using a timer, the lens blanks are not waited for dissolution at the start of work. One block operation can be started. The meltable material usable temperature of the dropping device 14 is 0 to 120 ° C., and the melting temperature of the wax 4 is preferably 68 to 72 ° C. Moreover, it is preferable to hold | maintain at fixed temperature in any temperature. The melted wax 4 in the tank 61 is intermittently sent out to the pipe 63 by a constant amount from the discharge port 70 by the pump 64. As the pump 64, a known gear pump using two gears 71a and 71b meshing with each other as shown in FIG. 7 is used. Such a gear pump 64 is suitable because it can smoothly and reliably supply the wax 4 having high viscosity by a certain amount. The amount of wax 4 delivered by the gear pump 64 is accurately controlled by changing the number of pulses applied to the stepping motor 65.

  FIG. 8 is a diagram showing the relationship between the number of driving pulses applied to the stepping motor 65 and the amount of dripping wax 4. As is apparent from this figure, the dripping amount of the wax 4 shows extremely high linearity with respect to the number of pulses.

  Control of the dripping amount of the wax 4 is an important element in realizing the dripping device 14 that does not require the conventional blocking ring 3 shown in FIG. Too much wax 4 overflows from the concave surface 1a of the lens blank 1, and too little causes problems such as a decrease in the holding power of the block. However, in the present invention, it can be controlled with high precision by the dropping device 14, so that Therefore, an optimal amount of wax 4 can be dropped according to various lens blanks 1.

  The capacity of the tank 61 is 10.56 liters (width 440 × depth 240 × height 100 mm), the heater 67 of the tank 61 is 100 V, 300 W, and the heater 68 of the pipe 63 is 100 V, 17 W. The diameter of the opening of the nozzle 62 is 3 mm, and the dropping valve 66 for opening and closing the nozzle 62 is a pin cylinder made of SMC (CDJPL10-5D-97LS).

In FIG. 2 again, the interval setting mechanism 15 for moving the Yatoi 2 up and down to set the interval with the lens blanks 1 to a predetermined interval is provided behind the centering mechanism 13 and holds the Yatoi 2. The holding arm 80, a ball screw 81 that supports the holding arm 80 so as to move up and down, and a stepping motor (not shown) that rotates the ball screw 81 are configured. A distal end portion of the holding arm 80 extends above the mounting table 11, and a vacuum chuck (not shown) for detachably holding the yatoe 2 is provided on the lower surface. The center of the vacuum chuck coincides with the center of the mounting table 11. The holding arm 80 is moved up and down by the rotation of the ball screw 81, descends at the time of blocking, and presses the Yato 2 against the wax 4 dripped onto the lens blank 1. For this reason, the wax 4 spreads and spreads over the entire block surface 2 a of the yatoy 2, and the lens blanks 1 can be blocked by the yatoy 2. Lowering amount of lens holder unit 2, the number of pulses peripheral edge of the concave 1a of the lens blank 1 is applied to the stepping motor to the lower surface of the engaging portion 31A of the clamp pin 31 abuts the reference height (the height of the block position H ₂₎ And a predetermined distance d between the lens blanks 1 and the yatoy 2, in other words, the thickness of the end of the wax 4 is set to a predetermined thickness. Specifically, the gap d and the dripping amount Q of the wax 4 are set to the thickness Te at the end of the wax 4 after spreading, the curvature radius R of the concave surface 1a of the lens blank 1, the outer diameter LDb, and the edge thickness of the yatoy 2. It is calculated from at least one of YH (the thickness from the back surface of the disc portion 2A to the outer peripheral edge of the convex surface 2a in FIGS. 1 and 5), the outer diameter YDh of the yatoy 2, and the curvature radius Ch of the convex surface 2a of the yatoy 2.

  Here, in the present invention, a parameter of “Yatocoba thickness YH + wax edge thickness Te” is defined for the positional relationship between Yato 2 and lens blanks 1 at the time of blocking, and this is set to 7 mm. Further, the edge thickness Te of the wax 4 was set to 3 mm by setting the edge thickness YH of the yatoy 2 to 4 mm. Specific data is requested from a server that manages well-known order data (not shown), and is calculated from the parameter values sent from the server by the following formula.

  The lower end of the lens blank 1 and the outer peripheral edge of the blocking surface side of the lens blank 1 when the end thickness Te is set to a predetermined thickness are lowered by lowering the yatoy 2 and pressing the wax 4 on the lens blank 1. The vertical gap d is calculated by the following equation (1).

  Here, R is the radius of curvature of the concave surface 1 a of the lens blank 1, LDb is the outer diameter of the lens blank 1, and YDh is the outer diameter of the yatoy 2.

On the other hand, the vertical position coordinate of the outer peripheral edge of the blocking surface 2a of the yatoy 2 is a constant value YH (edge thickness) with respect to the reference surface 2b of the yatoy 2. Therefore, the yatoy 2 is controlled so that the end thickness of the wax 4 is Te (3 mm in this embodiment). That is, the height of the reference surface 2b of the lens holder unit 2 is positioned above only YH + d from (lower height of the engaging portion 31A of the clamp pin 31 to the concave outer periphery of the lens blank 1 strikes) the height of the block position H ₂ Yatoi 2 is lowered so that it does.

  The dripping amount Q of the wax 4 dripped onto the lens blank 1 is calculated by the following equation (2).

  Where Te is the thickness of the end of the wax 4, Cb is the radius of curvature on the concave surface 1 a side of the lens blank 1, Ch is the radius of curvature of the blocking surface (convex surface) of the yatoy 2, and 2Dh is the outer diameter of the wax 4 after spreading. is there.

  Moreover, the dripping amount Q of the wax 4 dripped on the lens blanks 1 is also calculated by the following equation (3).

  Where Tc is the thickness of the central portion of the wax 4 after spreading, 2Dh is the outer diameter of the wax 4 after spreading, Ch is the radius of curvature of the blocking surface 2a of the yatoy 2, and R is the radius of curvature of the concave surface of the lens blank 1. is there.

  When the dripping amount Q of the wax 4 is calculated, a predetermined number of pulses corresponding thereto is sent from the control unit to the stepping motor 65 that controls the rotation amount of the gear pump 64.

  As the control unit of the blocking device 10, a personal computer using Windows (2000) as an OS is used. In the communication system, an I / O board and a motor controller are connected via an ArcNet communication board to control the centering mechanism 13, the wax 4 dropping device 14 and the interval setting mechanism 15.

Next, the block operation of the lens blank 1 by the blocking device 10 having the above structure will be described mainly based on FIGS. 3 and 9 to 12.
First, the O-ring 18 and the pad 19 are placed on the placing table 11 (FIG. 3), and the lens blank 1 is placed thereon with the convex surface 1b facing down (FIG. 9).

  In addition, the yatoy 2 corresponding to the lens blank 1 is attached to the lower surface of the front end of the holding arm 80 with the blocking surface 2a facing down (FIG. 4).

  Next, the lens blanks 1 are centered. In this centering operation, the air cylinder 39 is driven to rotate the rotary base 36 by a predetermined angle in the direction of arrow A in FIG. Thereby, each clamp pin 31 moves in the center direction of the rotation base 36 and presses the edge surface 1c of the lens blank 1 to make the geometric center of the lens blank 1 coincide with the center of the mounting table 11 (FIG. 4).

When the centering work of the lens blank 1 is completed, the lens blank 1 is lifted by the air cylinder 12 is moved to the block position H _2. That is, when the air cylinder 12 is driven, the support shaft 17 and the mounting table 11 are integrally raised, so that the lens blank 1 is raised along the clamp pin 31 to the block position H ₂ (FIG. 10), and the outer peripheral edge of the concave surface 1a. Is fixed by being pressed against the lower surface of the locking portion 31 </ b> A of the clamp pin 31.

Next, the slide plate 22 is moved from the block position H ₂ to the dropping position H ₃ (FIG. 2) by a driving device such as an air cylinder and stopped, and the dropping device 14 moves the wax 4 to the center of the concave surface 1a of the lens blank 1. A predetermined amount is dropped. The dripping of the wax 4 is performed by driving the gear pump 64 for a predetermined time by driving the stepping motor 65 as shown in FIG. 6 to push out a predetermined amount of wax 4 from the tank 61 to the pipe 63, and the tip of the pipe 63 by the extrusion pressure. A predetermined amount of the wax 4 accumulated in the section is dropped from the nozzle 62 onto the concave surface 1 a of the lens blank 1. At this time, the dropping valve 66 operates in synchronization with the gear pump 64 to open and close the nozzle 62.

When the dropping of the wax 4 is completed, the slide plate 22 returns from the dropping position H ₃ to the block position H ₂ . When the slide plate 22 is returned to the block position H ₂ , the distance setting mechanism 15 operates to lower the holding arm 80 holding the Yato 2 by a predetermined amount (FIG. 11), and the blocking surface 2 a of the Yato 2 is moved to the lens blank. It is pressed against the wax 4 dripped on the concave surface 1a of 1 to expand to a predetermined thickness (FIG. 12). In this state, when the wax 4 is naturally cooled or forcedly cooled for a certain time to be solidified, the lens blanks 1 are blocked by the yatoy 2. Thereafter, release the respective crank pin 31 from the lens blank 1, it is raised returning the holding arm 80 to the original height position and lowers the table 11 to return to the original centering position H _1, the lens blank 1 End blocking work.

As described above, in the present invention, the dripping amount Q of the wax 4 is controlled without excess or deficiency according to the lens blanks 1, and the distance between the concave surface 1a of the lens blanks 1 and the yatoy 2 is set to the predetermined distance d. 2 is controlled so that the amount of dripping Q of the wax 4 is neither too much nor too little, and the wax 4 can be expanded to a predetermined thickness. Also, since the move to raise the lens blank 1 at block blocking position H _2, even various lens blank 1 edge thickness different be positioned reliably concave 1a blocking position H ₂ it can.
Further, the centering mechanism 13 has a simple configuration, a small number of parts, and can be manufactured at low cost.
Further, since the mounting table 11 is swingably supported by the swing mechanism 20, even if the lens blanks have different edge thicknesses in the circumferential direction, the concave surface 1a can be made horizontal, and the wax 4 There is no possibility that the wax 4 overflows from the concave surface 1a when dripping, and the wax 4 can be reliably blocked.
Furthermore, if the wax 4 does not overflow from the concave surface 1a of the lens blank 3, the conventional blocking ring 3 shown in FIG. 13 is not required, and the number of parts for blocking can be reduced.

In the above-described embodiment, polyethylene wax is used, but other paraffin wax, microcrystalline wax, Fischer-Tropsch wax, oil synthetic wax, and other synthetic waxes are relatively low if heated at room temperature. If it becomes a viscous liquid, it can be used as the bonding agent of the present invention. Further, not only wax but also a low melting point alloy may be used.
Furthermore, the present invention is not limited to the above-described embodiment, and various modifications and changes can be made.

It is a figure which shows the state which blocked the lens blanks with Yatoi. It is an external appearance perspective view of the principal part of the blocking apparatus which concerns on this invention. It is a perspective view of the centering mechanism part of the same apparatus. It is sectional drawing of the centering mechanism part. It is a figure which shows the state which latched the lens blank in the block position. It is a figure which shows a dripping apparatus. It is a figure which shows the inside of a gear pump. It is a figure which shows the relationship between the dripping amount of a wax, and the number of pulses. It is a figure for demonstrating the block operation | movement of a lens blank. It is a figure for demonstrating the block operation | movement of a lens blank. It is a figure for demonstrating the block operation | movement of a lens blank. It is a figure for demonstrating the block operation | movement of a lens blank. It is sectional drawing which shows a prior art example when blocking a lens blank using a blocking ring.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Lens blanks, 2 ... Yatoi, 3 ... Wax, 10 ... Blocking device, 11 ... Mounting stand, 12 ... Moving device, 13 ... Centering mechanism, 14 ... Dropping device, 15 ... Space | interval setting mechanism, 20 ... Swing mechanism, DESCRIPTION OF SYMBOLS 30 ... Clamp board, 31 ... Clamp pin, 31A ... Locking part, 33 ... Clamp base, 34 ... Fixed shaft, 36 ... Rotation base 36, 40 ... Centering mechanism, 43 ... Long hole, 44 ... Moving shaft, 45 ... Clamp pin, 62 ... nozzle, 64 ... gear pumps, 65 ... stepping motor, H ₁ ... centering position, H ₂ ... block position, H ₃ ... dropping position.

Claims (4)

In an optical lens blocking device for fixing the optical lens to the lens holder by interposing a molten bonding agent between the optical lens and the lens holder to be cooled and solidified,
A mounting table on which the optical lens is mounted with its concave surface up;
A centering mechanism for matching the geometric center of the optical lens with the center of the mounting table,
A dropping device that drops the bonding agent onto the concave surface of the optical lens;
An optical lens blocking device comprising: a moving device that moves the optical lens to a block position of the lens holder. The optical lens blocking device according to claim 1,
The centering mechanism includes a plurality of pins that are provided around the mounting table so as to be movable in a radial direction and a circumferential direction of the mounting table, and press the edge surface of the optical lens, and a concave surface of the optical lens is provided at the upper end of these pins. An optical lens blocking device comprising a locking portion for locking a side outer peripheral edge to a block position. The optical lens blocking device according to claim 1,
The centering mechanism includes a clamp base that surrounds the mounting table, a rotation base that is rotatably incorporated in the clamp base, a drive device that rotates the rotation base, and a fixed shaft that projects from the clamp base. A plurality of freely provided clamp plates, a moving shaft projecting on the rotation base and slidably inserted into a long hole provided in each clamp plate, and a tip of each clamp plate An optical lens blocking device comprising a plurality of pins which are erected and press the edge of the optical lens. The optical lens blocking device according to any one of claims 1, 2, and 3,
A drive device that raises the mounting table and moves the optical lens to the block position along the pin,
An optical lens blocking device, wherein the mounting table is swingably supported by a swing mechanism.

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