Lens shape measuring method and lens shape measuring apparatus

A lens shape measuring method includes: bringing a feeler into contact with an outer peripheral surface of a spectacle lens, the outer peripheral surface corresponding to a lens shape of spectacles, the feeler being rotatable about a rotation axis and movable forward and backward relative to the rotation axis in a radial direction, and, while keeping the contact state, moving the feeler along a contact surface of the feeler with the lens shape in a circumferential direction, to measure radii ρi (i=0, 1, 2, . . . n) of the lens shape over an entire circumference of thereof, the radii ρi representing change in distance from a geometric center of the lens shape to the feeler, a measurement region of the lens shape being divided into multiple sub-regions, and within each of the sub-regions, the rotation axis line being moved to a position to cause the feeler to measure the lens shape within the sub-region.

CROSS-REFERENCE TO THE RELATED APPLICATION

The present application is based on and claims priority from Japanese Application Number 2008-254306, filed on Sep. 30, 2008, the disclosure of which is hereby incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a lens shape measuring method and a lens shape measuring apparatus for measuring, in terms of lens shape: a lens frame shape of a spectacle frame; and an outer diameter shape of a template, a dummy lens, or the like.

2. Description of the Related Art

Conventionally there has been a kind of lens shape measuring apparatus for measuring a lens shape for a lens frame and the shape of a spectacle lens. The lens shape measuring apparatus of this kind includes: a lens frame feeler for measuring the inner peripheral surface shape (lens fitting groove (V-shaped groove) shape) of a lens frame of a spectacle frame; and a lens shape feeler for measuring the outer peripheral surface shape of a lens shape of a template, a dummy lens or the like (for example, refer to Japanese Unexamined Patent Application Publication No. H7-164295).

This conventional lens shape measuring apparatus includes: a rotation base mounted rotatably about a vertical rotation axis line; a slider mounted on the rotation base movably forward and backward in a radial direction of rotation about the rotation axis line; the lens frame feeler vertically movably held by the slider, and the lens shape feeler tiltably mounted on the slider.

With this conventional lens shape measuring apparatus, the measurement is performed as follows. Specifically, while the rotation base is horizontally rotated about the rotation axis line, the lens frame feeler is moved along a lens fitting groove of a lens frame or the like in the circumferential direction or the lens shape feeler is moved along the outer peripheral surface of a lens in the circumferential direction. During the movement, the amount of movement of the feeler in the horizontal direction (in the radial direction of the rotation about the rotation axis line) is measured with respect to the rotation angle θi of the rotation base about the rotation axis line. Thus, change in distance from the geometric center of the lens shape to the feeler is measured as radii ρi.

In a measurement using such a conventional lens shape measuring apparatus, just before left and right spectacle lens frames are held by a frame holding section and the shape thereof is measured, the feeler mounted on the slider is arranged at a position corresponding to a geometric center of a left or right lens frame of spectacles having average-sized lens frames and having a distance between geometric centers of the left and right lens frames (frame pupil distance: FPD) in an average range. Then, this feeler is brought into contact with a measurement starting position of a lower rim part of the lens frame. Note that the maximum moving amount of this feeler in the horizontal direction (in the radial direction of the rotation about the rotation axis line) from the position immediately before the start of a measurement is predetermined.

While the rotation base is rotated horizontally about a vertical axis, amounts of horizontal movement of the feeler from the contact position of the feeler with the lower rim part with respect to rotation angles θi about the vertical axis of the rotation base are measured as radii ρi, so that lens shape data (θi, ρi) for the lens frame is obtained.

The larger the sizes of lens frame shapes (lens shapes) of left and right lens frames, the longer the distance FPD between the geometric centers of the left and right spectacle lens frames. For this reason, there has been a problem that, the larger the lens frames relative to those of average-sized spectacles, the larger the discrepancy between the setting position of the feeler immediately before the start of the measurement and the position of the geometric center of one of the lens frames.

Further, the conventional lens shape measuring apparatus as described above has the following problem because the maximum moving amount of the feeler in the horizontal direction (in the radial direction of the rotation about the rotation axis line) is predetermined. Specifically, in a lens frame shape measurement on a lens frame of large spectacles whose distance between the geometric centers of the left and right lens frames, i.e., FPD, is long, if the measurement is started at a measurement start position which is set for measurement on spectacles having average-sized lens frames, the feeler may get out of contact with the lens fitting groove in some cases. Likewise, in a measurement on a template for lens frames of large spectacles whose distance between the geometric centers of the left and right lens frames, i.e., FPD, is long, if the measurement is started at the measurement start position, the feeler stops and no further measurement on the template is possible because of the predetermined maximum moving amount of the feeler in the horizontal direction.

A larger maximum moving amount of the feeler in the horizontal direction (in the radial direction of the rotation about the rotation axis line) can prevent such problems. In such a case, however, a measurement unit of the lens shape measuring apparatus is larger in size, and consequently the lens shape measuring apparatus as a whole is larger in size.

SUMMARY OF THE INVENTION

In this connection, an object of the present invention is to provide a lens shape measuring method and a lens shape measuring apparatus capable of measuring a large lens shape without enlargement in size of the apparatus as a whole.

To achieve this object, a lens shape measuring method according to one embodiment of the present invention includes the steps of bringing a feeler into contact with any one of an inner peripheral surface of a lens frame and an outer peripheral surface of a spectacle lens or a template, each of the inner peripheral surface and the outer peripheral surface corresponding to a lens shape of spectacles, the feeler being rotatable about a rotation axis and movable forward and backward relative to the rotation axis in a radial direction, and while keeping the contact state, moving the feeler along a contact surface of the feeler with the lens shape in a circumferential direction, to thereby measure radii ρi (i=0, 1, 2, . . . n) of the lens shape over an entire circumference of the lens shape, the radii ρi representing change in distance from a geometric center of the lens shape to the feeler. Moreover, a measurement region of the lens shape is divided into multiple sub-regions, and within each of the sub-regions, the rotation axis line (the rotation center O5) is moved to a position with which the feeler (a lens shape prove36or a lens frame prove37) is capable of measuring the lens shape to thereby cause the feeler to measure the lens shape within the sub-region.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, a description is given of embodiments of the present invention based on the drawings.

FIG. 1Ashows a configuration of a main portion of a lens shape measuring apparatus according to the present invention (also serving as a spectacle lens frame shape measuring apparatus), which includes a measuring apparatus body1. The measuring apparatus body1includes: a case section1afor accommodating a measuring mechanism located in lower part; and a lens frame holding mechanism1bprovided above the case section1a. In the bottom of the case section1aofFIG. 1A, a base2shown inFIG. 2is provided.

The lens frame holding mechanism1bincludes a pair of parallel guide rods (guide members)1cand1cwhich are fixed to the case section1a. On the guide members1cand1c, slide frames3and3are held so as to approach and separate from each other.

The slide frames3and3are biased by a not-shown coil spring or the like so as to approach to each other. Each of the slide frames3and3includes: a vertical wall3awhich faces a vertical wall3aof the other slide frame3and is caused to abut on spectacle lens frames (not shown); and lens frame holders (holding device)3bholding the spectacle lens frames.

Each of the lens frame holders3bincludes a lower holding bar3b1(holding pin) protruding from the vertical wall3aand an upper holding bar3b2(holding pin) attached to the slide frame3so as to open and close from above the holding bar3b1. The lens frame holders3bare provided to right and left lens frames of not-shown spectacles, respectively.

Such lens frame holding mechanisms1bcan employ a configuration disclosed in, for example, Japanese Patent Application Publication No. H10-328992 or the like or can employ other known techniques.

As shown inFIGS. 1A and 1Bto1D, the slide frame3includes a bottom surface400formed in a rectangle protruding downward. At the center of the bottom surface400, an opening400A is formed. The opening400A is configured to allow a lens frame feeler or probe37and an attachment hole feeler38to be inserted therethrough upward from the bottom side. The lens frame feeler37and attachment hole feeler38are described later.

The bottom surface400may be a cylindrical surface protruding downward. Moreover, to an outer surface401of the slide frame3, a guiderail403having a belt-like shape curved in an arc around a virtual axis402is attached.

Meanwhile, the measuring apparatus body1includes brackets405and405standing up on each upper end of a lower case404. Each of the brackets405and405is provided with a rotatable supporting skid406in upper part and a rotatable supporting skid407below the supporting skid406. The supporting skids406and407of each bracket405are arranged so as to sandwich the guiderail403of the slide frame3at upper and lower positions.

The both slide frames3are supported on the lower case404of the measuring apparatus body1through the guiderails403sandwiched by the supporting skids406and407at the upper and lower portions. The both slide frames3can therefore swing in a direction of an arrow D around the virtual axis402.

As shown inFIG. 1F, on a lower edge of each guiderail403, a belt408is provided. Both ends of the belt408are fixed to the lower edge of the guiderail403, and the other part thereof is not fixed to the lower edge of the guiderail403. In other words, the part of the belt408other than the both ends can be separated from the lower edge of the guiderail403.

On the lower case404of the measuring apparatus body1, motors409(seeFIGS. 1B to 1E) as a driving section are provided. On an output shaft of each motor409, a driving skid410is attached. The driving skid410is placed substantially in the middle between the supporting skids407and407respectively attached to the brackets405and405on both sides thereof and below the supporting skids407and407.

The belt408provided on the lower edge of the guiderail403is wound around one of the supporting skids407and407, wound around the driving skid410, and then wound around the other supporting skid407. The upper surface of the belt408(the surface brought into contact with the lower edge of the guiderail403) is jagged, and the outer circumferential surface of the driving skid410is also jagged.

This results in providing a large coefficient of friction between the upper surface of the belt408and the outer circumferential surface of the driving skid410. Accordingly, when the driving skid410rotates, the belt408moves to the right or left inFIG. 1Fwithout slipping. The slide frame3can be therefore swung in the direction of the arrow D around the virtual axis402(seeFIGS. 1B and 1D).

The guiderails403, supporting skids406and407, belts408, motors409, and driving skids410constitute a holding unit swinging mechanism.

On the base2, a measurement mechanism1das shown inFIGS. 2 to 5Ais provided. The measurement mechanism1dincludes a base supporting member4fixed on the base2. To the base supporting member4, a large-diameter driven gear5is attached so as to horizontally rotate around a vertical axis.

To the base2, a driving motor6schematically shown inFIG. 5Bis attached adjacent to the driven gear (timing gear)5. On an output shaft6aof the driving motor6, a pinion (timing gear)7is fixed. A timing belt8is wound around the pinion7and driven gear5.

When the driving motor6is activated, rotation of the output shaft6aof the driving motor6is transmitted through the pinion7and timing belt8to the driven gear5, and thereby rotates the driven gear5. Here, the driving motor6is a two-phase stepping motor.

As shown inFIGS. 2 to 5A, a rotation base9is integrally fixed on the driven gear5.

To the rotation base9, a photosensor9aas an origin detecting device (origin detector) is attached.

In this case, for example, a light emitter9bfor indicating an origin is provided on the base2, and a linear or spot light beam is emitted from the light emitter9bupward as an origin mark. The position of origin of horizontal rotation of the rotation base9can be set to the position where the photosensor9adetects the light beam as the origin mark.

The origin detecting device can employ a known technique such as a transmissive photosensor, a reflective photosensor, or a proximity sensor.

Furthermore, to both ends of the rotation base9in the longitudinal direction, as shown inFIGS. 2 to 4, rail attachment plates10and11, which vertically extend and face each other in parallel, are integrally fixed. As shown inFIG. 3, to an end of the rail attachment plate10and an end of the rail attachment plate111, longitudinal ends of a side plate12are respectively fixed. As shown inFIG. 4, to the other end of the rail attachment plate10and the other end of the rail attachment plate111, longitudinal ends of a side plate13are respectively fixed.

As shown inFIGS. 2 to 4, a pair of shaft-shaped guide rails14and14parallel to each other is horizontally provided between upper halves of the rail attachment plates10and11facing each other. The both ends of each guiderail14are fixed to the rail attachment plates10and11, and a slider15is held on the guiderails14and14so as to advance and retract in the longitudinal direction.

As shown inFIGS. 2 and 3, a pulley supporting plate section12ahorizontally protruding laterally is formed by bending integrally with the side plate12in the vicinity of the rail attachment plate10. Moreover, a bracket16for motor attachment is fixed to the side plate12in the vicinity of the rail supporting plate11.

To the pulley supporting plate section12a, a driven pulley17is attached so as to horizontally rotate around an axis vertically extending, and the upper end of a driving motor18for moving a slider is fixed to the bracket16. Here, the driving motor18is a DC motor.

An output shaft18aof the driving motor18includes an axis line vertically extending and is attached to a driving pulley19as shown inFIGS. 5C and 5D.

A ring-shaped wire20is wound around the pulleys17and19, and a portion of the wire20in the vicinity of an end thereof is held by a shaft-shaped wire holding member21. This wire holding member21is fixed to the slider15through brackets22and22′.

The both ends of the wire20are connected through a coil spring23. When the driving motor18is operated forward or backward, the output shaft18aand driving pulley19are rotated forward or backward, and the slider15is thus moved to the right or left inFIG. 3.

As shown inFIG. 5E, an origin sensor (an origin detector)20adetecting the origin of movement position of the slider15(an amount of movement) is provided between the bracket22′ and side plate12. Here, the origin sensor20ais a reflection-type sensor. This sensor includes a reflector20bprovided with a slit-shaped reflecting surface vertically extending (not shown) and a reflective photosensor20cincluding light emitting and receiving elements.

The reflector20bis provided for the bracket22′, and the photosensor20cis provided for the side plate12.

The origin sensor20acan employ a known technique including a transmissive photosensor, a proximity sensor, or the like.

At the longitudinal center of the side plate13ofFIG. 4, a supporting plate section13ahorizontally protruding laterally is formed by bending integrally with the side plate13as shown inFIG. 4. Between the side plate13and slider15, as shown inFIG. 4, a linear scale (a position measuring unit)24detecting the horizontal movement position of the slider15in the direction that the guiderails14and14extend is provided as a radius detection sensor (a radius detector).

The linear scale24is provided with: a shaft-shaped main scale25held by the slider15in parallel to the guiderails14and14; and a detection head26fixed to the supporting plate section13aand reads position information of the main scale25.

The detection head26is configured to detect the horizontal movement position of the slider15from position detection information (movement amount detection information) provided by the main scale25. Here, the linear scale24can be, for example, of a known magnetic or optical type.

For example, in the case of a magnetic type, magnetic patterns of magnetic polarities S and N are alternately provided on the main scale25at minute intervals in the axial direction as the position detection information (movement amount detection information). These magnetic patterns are detected by the detection head (magnetic change detection head)26to detect the amount of movement (movement position) of the slider15.

In the case of an optical type, the main scale25is formed into a plate, and slits are provided in the main scale25at minute intervals in the longitudinal direction thereof. Moreover, light emitting and receiving elements are provided so as to sandwich the main scale25. Light from the light emitting element is detected by the light receiving element through the slits of the main scale25to obtain the number of slits, thus detecting the amount of movement (movement position) of the slider15.

Substantially at the center of the slider15, a through-hole15ais formed as shown inFIG. 2. Through the through-hole15a, a guide cylinder27vertically extending is inserted. Under the slider15, a supporting frame28is provided as shown inFIG. 4.

The supporting frame28includes: vertical frames29and30whose upper ends are held by the slider15; and a horizontal plate (a bottom plate)31fixed to the lower ends of the vertical frames29and30.

To the horizontal plate (bottom plate)31, lower ends of a pair of shaft-shaped supporting members32and32, which vertically extend in parallel to each other, are fixed (seeFIG. 8). To upper ends of the supporting members32and32, a holding member (a coupling member)33is fixed. To the holding member33, a vertical wall34aof a guide supporting member34is fixed, the guide supporting member34having an L-shaped side surface. On a horizontal wall (an upper wall)34bof the guide supporting member34, a lower end of the guide cylinder27is fixed.

A feeler shaft35vertically extending is fitted to and held by the guide cylinder27so as to vertically move. At an upper end of the feeler shaft35, a lens shape feeler (a lens rim shape feeler)36is integrally provided. The lens shape feeler36includes: an attachment section36avertically attached to the upper end of the feeler shaft35; and a vertical section36bextending upward from the attachment section36a. The attachment section36aand vertical section36bform an L shape.

A back surface36cof the vertical section36is processed at a constant R (seeFIG. 10A) for lens rim shape measurement. At the upper end of the vertical section36b, the lens frame feeler37(a feeler) is integrally formed in parallel to the attachment section36a.

Note that, herein, the feeler represents any of the lens shape feeler36, the lens frame feeler37and the attachment hole feeler38.

The horizontal movement of the slider15guided by the guide rail14causes this feeler shaft35and these feelers36and37to move forward or backward in the radial direction relative to a rotational center (rotation axis line) O5shown inFIG. 5B, which is the rotation axes line of the driven gear5and the rotation base9. Note that the amount of the forward and backward movement of the feeler shaft35and the feelers36and37in the radial direction varies depending on the length of the guide rail14, the size of the slider15, and the like. The maximum moving amounts of the feeler shaft35, the feelers36and37in the radial direction are predetermined.

Moreover, at the upper end of the lens shape feeler36, as shown inFIG. 10A, the attachment hole feeler38protruding upward is integrally provided. The attachment hole feeler38includes: a shaft38awhich is integrally attached to the upper end of the vertical section36bof the lens shape feeler36in parallel to the axis line of the feeler shaft35; and a hemisphere38bprovided at the upper end of the shaft38a. For coping with attachment holes with a wide variety of sizes, it is desirable that the hemisphere38bhave a hemispherical shape larger in diameter than a general attachment hole (2.2φ).

The attachment hole feeler38is not necessarily integrated with the lens-shape feeler36unlike described above. For example, as shown inFIG. 9, the lens-shape feeler36may be detachably attached to the upper end of the vertical section36bof the lens shape feeler36by providing a thread36sfor the lens shape feeler36as shown inFIG. 9and screwing the thread36sto the upper end of the vertical section36b.

As shown inFIGS. 6 to 8, a bracket39is fixed to the lower end of the feeler shaft35. Moreover, as shown inFIG. 13, a linear scale (a position measuring unit)40detecting a vertical movement position is provided between the bracket39and guide supporting member34as a height detection sensor (a height detector).

The linear scale40includes a shaft-shaped main scale41and a detection head42. The main scale41is provided in parallel to the feeler shaft35to extend vertically. The detection head42detects the vertical movement positions of the feelers37and38based on the amount of vertical movement of the main scale41. The upper end of the main scale41is fixed to the holding member33, and the lower end thereof is fixed (or held) to the bracket39.

The detection head42is held by the holding member33. The linear scale40is also of a magnetic or optical type similar to the aforementioned linear scale24.

As shown inFIGS. 6 to 8, a coil spring43biasing the feeler shaft35upward is provided between the bracket39and horizontal plate (bottom plate)31. Furthermore, an engagement shaft44is attached to the lower end of the feeler shaft35. The engagement shaft44is placed above the bracket39and is perpendicular to the feeler shaft35.

On the horizontal plate (bottom plate)31, as shown inFIG. 6, a U-shaped bracket45is fixed. Both ends of a supporting shaft46are held by opposite walls45aand45aof the bracket45so as to rotate around the axis line. A holding lever47is fixed to the supporting shaft46and is caused to abut on upper part of the engagement shaft44.

A tension coil spring48for pulling down the holding lever47is provided between the holding lever47and horizontal plate31. Tension spring force of the tension coil spring48is set larger than spring force of the coil spring43.

A vertical position control lever49is fixed on the supporting shaft46. The vertical position control lever49is used to control the position to which the engagement shaft44is raised by the holding lever47and used to set positions to which the feeler shaft35, lens frame feeler37, and lens shape feeler36are raised. The vertical position control lever49extends in a same direction as the holding lever47extends.

Below the vertical position control lever49, an actuator motor50is provided. The actuator motor50includes a motor body50afixed on the horizontal plate31; and a shaft51which protrudes upward from the motor body50aand includes an axis line in parallel to the feeler shaft35. The vertical position control lever49is caused to abut on the upper end of the shaft51by the tension spring force of the tension coil spring48.

Here, the actuator motor50is also a pulse motor. The actuator motor50is configured to operate forward to advance the shaft51upward and operate backward to move the shaft51downward.

The coil spring43, supporting shaft46, holding lever47, tension coil spring48, vertical position control lever49, actuator motor50, and the like constitute a mechanism of raising the feelers37and38.

As shown inFIG. 10B, an origin detection signal from the aforementioned photosensor (origin detector)9a, an origin detection signal from the photosensor (origin detector)20c, a movement amount detection signal (position detection signal) from the detection head26of the linear scale24, a movement amount detection signal (position detection signal) from the detection head42of the linear scale40, and the like are inputted to a calculation control circuit (a calculation controller, a control circuit)52. The calculation control circuit52is configured to operate and control the drive motors6and18and actuator motor50.

Moreover, as described later, the calculation control circuit52corrects the results of shape measurement of spectacle lens frames with a large curved angle according to the axial shift amount or angle, and outputs the corrected shape measurement result.

A holder detector53is provided on a side wall of one of the slide frames3and3as shown inFIG. 1A. The holder detector53is composed of a micro switch or the like. A detection signal from the holder detector53is inputted to the calculation control circuit52as shown inFIG. 10B.

InFIG. 10B, a reference numeral54denotes a start switch for starting measurement; and55, a memory connected to the calculation control circuit52.

Hereinafter, operation of such a lens shape measuring apparatus will be described.

(A). Regarding Spectacle Frame

There are two types of spectacle frames, a rim-type frame and a rimless-type frame.

The rim-type spectacle frame includes a frame main body and right and left temples. The frame main body is formed of a left lens frame (left annular rim) and a right lens frame (right annular rim) integrally connected with a bridge. The right and left temples are mounted on the ear sides of the left and right lens frames, respectively, of the frame main body. In addition, the left and right lens frames each have a lens fitting groove which extends annularly along the inner peripheral surface of the corresponding lens frame and which is formed to have a substantially V-shaped cross-section. In spectacles with such lens frames, each spectacle lens is fitted into the lens frame in a way that a lens fitting protrusion having a triangular cross-section and protruding annularly on the peripheral surface of the spectacle lens engages with the lens fitting groove of the lens frame.

The rimless-type spectacle frames are classified into a semi-rimless frame (grooved frame) having partial rims and a rimless frame having no rim.

The semi-rimless frame includes a rim bar (frame main body) and left and right temples. The rim bar is formed of left and right upper-half rims integrally connected with a bridge. The left and right temples are mounted on left and right edges (on the ear sides), respectively, of the rim bar.

The rimless frame includes a bridge and left and right temples. The bridge fixes left and right spectacle lenses on the nose sides. The left and right temples are mounted on the ear sides of the left and right spectacle lenses, respectively.

In spectacles with the semi-rimless frame (grooved frame), each of the spectacle lenses is suspended and held by a resin band (suspension string) in a way that a band groove is formed in the lower half of the outer peripheral surface of the spectacle lens and that each end portion of the resin band (suspension string) provided to the band groove is fixed to the corresponding upper-half rim bar. Meanwhile, in spectacles with the rimless frame, the bridge is fixed to the nose sides of the left and right spectacle lenses by using screws, and the left and right temples are fixed to portions on the ear sides of the left and right spectacle lenses, respectively, by using screws.

The inner peripheral surface shape of the above-described lens frame (i.e., the shape of the lens fitting groove, which corresponds to the lens frame shape) and the outer shape (outer peripheral surface shape) of the spectacle lens are known as a lens shape used during spectacle lens processing. Note that examples of the spectacle lens include: lenses actually produced on the basis of a prescription for eyes of those who will wear the spectacles; and plano lenses mounted on (held by) a spectacle frame for the purpose of display at opticians and the like (hereinafter, simply referred to as dummy lens).

(B). Measurement of Average-Sized or Normal Lens Shape

(I) Measurement of Lens Frame Shape

Before measurement of the shape of lens frames of spectacles or measurement of the shape of a lens such as a demo lens is performed by the lens shape measuring apparatus, the upper end of the shaft51of the actuator motor50is positioned at the bottom end (a bottom dead point) as shown inFIGS. 6 to 8. At this position, the holding lever47is biased by the tension coil spring48having stronger spring force than that of the coil spring43so as to rotate downward around the supporting shaft46. The holding lever47therefore presses down the feeler shaft35through the engagement shaft44. The lens frame feeler37and lens shape feeler36are thus positioned at the lowest end.

In the case of performing the measurement of the shape of the lens frames of spectacles with the lens shape measuring apparatus in the aforementioned state, as disclosed in Japanese Patent Application Publication No. H10-328992, for example, a spectacle frame MF including right and left lens frames LF and RF inFIG. 7is placed between the slide frames3and3ofFIG. 1A(the spectacle frame MF is not shown inFIG. 1A), and the lens frames LF and RF are sandwiched by the holding bars3b1and3b2as shown inFIG. 7. This is the same as that of Japanese Patent Application Publication No. H10-328992.

The lens frame LF (RF) held between the holding bars3b1and3b2is set above the lens frame feeler37before the measurement starts as shown inFIG. 7. Specifically, the lens frame feeler37is positioned at an initial position (α) below the lens frame LF (RF). Moreover, as shown inFIG. 7, the lens frame feeler37and attachment hole feeler38are positioned so as to correspond to an initial position (i) located substantially in the center of the lens frame LF (RF) held between the holding bars3b1and3b2.

At this position, the photosensor9adetects the origin of horizontal rotation of the rotation base9based on the light beam from the light emitter9b, and the origin sensor20adetects the origin of movement of the slider15.

Even if the lens frame three-dimensionally curves, the part of the lens frame held by the holding bars3b1and3b2is set lower than the other part. At the held part, a lens fitting groove Ym of the lens frame Lf (RF) has a set height, which is a lens frame shape measurement start position G.

When the start switch54ofFIG. 10Bis turned on at this state, the calculation control circuit52causes the actuator motor50to run forward and advance (raise) the shaft51upward from the position shown inFIGS. 6 to 8to the position shown inFIGS. 11 to 14by a predetermined amount. At this time, the shaft51raises the free end of the vertical position control lever49upward by a predetermined amount against spring force of the tension coil spring48so as to integrally rotate the vertical position control lever49and supporting shaft46.

The holding lever47is then rotated integrally with the supporting shaft46, and the free end of the holding lever47is raised upward by a predetermined amount. Upon the free end of the holding lever47being raised, the engagement shaft44is raised by spring force of the coil spring43following the free end of the holding lever47, and the feeler shaft35is thereby raised by a predetermined amount.

The amount of rise of the prove shaft35, or the amount by which the shaft51is advanced (raised) by the actuator motor50is an amount L by which the top of the lens frame feeler37rises from the initial position (α) ofFIG. 7to a height (β) corresponding to the height of the lens fitting groove Ym at the aforementioned shape measurement start position G.

The calculation control circuit52then drives and controls the driving motor18to rotate the driving pulley19and move the slider15along the guiderail14with the wire20ofFIGS. 2 and 5C. At this time, the slider15is moved in a direction of an arrow A1inFIG. 7. The movement is performed until the tip of the lens frame feeler37is abutted on the lens fitting groove Ym at the shape measurement starting position G as shown inFIG. 12. Moreover, in the state where the tip of the lens frame feeler37is in contact with the lens fitting groove Ym, the lens frame feeler37is brought into an elastic contact with the lens fitting groove Ym by the spring force of the coil spring23. In this state, the driving motor18is stopped.

When the tip of the lens frame feeler37comes into contact with the lens fitting groove Ym, the load on the driving motor18increases, and the current flowing the driving motor18increases. By detecting this change in current, the calculation control circuit52can detect that the tip of the lens frame feeler37comes into contact with the lens fitting groove Ym and stop the driving motor18.

Thereafter, the calculation control circuit52causes the actuator motor50to run forward and advances (raises) the shaft51upward from the position inFIGS. 11 to 14to the position inFIGS. 15 to 17by a predetermined amount. At this time, the shaft51raises the free end of the vertical position control lever49upward against the spring force of the tension coil spring48by a predetermined amount to rotate the vertical position control lever49integrally with the supporting shaft46.

The holding lever47is then rotated integrally with the supporting shaft46, and the free end thereof is raised upward by a predetermined amount and is separated from the engagement shaft44by a predetermined amount. The feeler shaft35can therefore move vertically.

Next, the calculation control circuit52drives and controls the driving motor6to cause the driving motor6to run forward. The rotation of the driving motor6is transmitted through the pinion7and timing belt8to the driven gear5, which is then horizontally rotated integrally with the rotation base9(seeFIG. 5B).

Along the rotation of the rotation base9, the slider15and a number of parts provided for the slider15are horizontally rotated integrally with the rotation base9, and the tip of the lens frame feeler37slides and moves along the lens fitting groove Ym. At this time, the slider15moves along the guiderail14integrally with the lens frame feeler37. Accordingly, the amount of movement of the slider15from the origin position of the slider15is equal to the amount of movement of the tip of the lens frame feeler37. This amount of movement is calculated from the detection signal of the detection head26of the linear scale24by the calculation control circuit52.

Moreover, the dimension (length) between the center of the feeler shaft35and the tip of the lens frame feeler37is known. Accordingly, by previously setting the distance between the rotational center of the rotation base9and the tip of the lens frame feeler37when the slider15is located at its origin, a change in distance between the rotational center of the rotation base9and the tip of the lens frame feeler37as the slider15moves along the guiderail14can be a radius ρi.

Accordingly, the rotation angle θi of the rotation base9due to the rotation of the driving motor6is calculated from the number of driving pulses of the driving motor6, and the radius ρi corresponding to the calculated rotation angle θi is obtained, thus obtaining the circumferential shape of the lens fitting groove Ym of the lens frame LF (RF) (lens frame shape) as lens frame shape information (θi, ρi) in the polar coordinate system.

Moreover, while the tip of the lens frame feeler37slides and moves along the lens fitting groove Ym of the lens frame LF (RF) which is curved in the vertical direction, the curve in the vertical direction is obtained as an amount of vertical displacement based on the detection signal of the detection head42of the linear scale40by the calculation control circuit52. This amount of vertical displacement is indicated by a vertical position Zi.

Accordingly, the lens frame shape of the lens frame LF (RF) can be calculated by the calculation control circuit52as three-dimensional lens frame shape information (θi, ρi, Zi). The thus-obtained three-dimensional lens frame shape information (θi, ρi, Zi) is stored in a memory55by the calculation control circuit52.

In this embodiment, at the lens frame shape measurement, the motor409is caused to run forward or backward and moves the belt408wound around the driving skid410in the right or left direction as shown inFIGS. 1F and 1D, thus swinging the entire slide frame3around the virtual axis402in the direction of the arrow D.

Moreover, for example, a highly curved frame for a +8 or more (up to +12) base curve lens, for example, is automatically inclined to prevent the feeler from being disengaged from the lens fitting groove of the frame and allow measurement of the bottom of the lens fitting groove. It is therefore possible to accurately measure also the frame PD.

Moreover, by swinging the entire slide frame3around the virtual axis approximated to the center of curvature of the curve of the frame, the frame for a +8 base curve lens can be horizontally held. Accordingly, the feeler can be accurately engaged with the lens groove, and the frame (lens frame) shape can be measured accurately.

(II) Measurement of Lens Shape of Demo Lens

(II-a) Setting of Lens of Demo Lens

In the case of performing shape measurement of right and left lenses Lm (MR) and Lm (ML) (demo lenses as dummies of spectacle lenses) of spectacles M with a two-point frame as shown inFIGS. 23A and 23Bby the lens shape measuring apparatus, known lens holders disclosed in Japanese Patent Application Publications No. H10-328992 and No. H8-294855 and the like can be used. To cause a lens holder of Japanese Patent Application Publication No. H10-328992 to hold a lens such as the demo lens, it is possible to employ a sucker and a sucker holding structure as disclosed in Japanese Patent Application Publication No. H8-294855. The structure of the lens holder is not essential for this invention, and thus the detailed description thereof is omitted.

The aforementioned lens holder holding lenses such as demo lenses is provided between the slide frames3and3, and a side wall of the lens holder of Japanese Patent Application Publication No. H10-328992 or a flange in side part of the lens holder of Japanese Patent Application Publication No. H8-294855 is sandwiched between the fixed holding bars3b1and movable holding bars3b2. At this time, the lenses held by the lens holder face downward.

In spectacles200with a two-point frame as shown inFIG. 23A, a bridge201is provided between the right and left lenses MR and ML (on the nose side), and temple clasps202and203are provided on opposite sides (on ear sides) of the right and left lenses Lm (MR) and Lm (ML).

As shown inFIG. 23B, the bridge201includes: side plates201aand201babutting on circumferential surfaces (cutting surfaces) of the lenses Lm (ML) and Lm (MR) on the nose side (edges of the circumferential surfaces facing each other), respectively; and fixed plates201cand201dabutting on rear refractive surfaces of the lenses Lm (ML) and Lm (MR), respectively.

As shown inFIG. 23B, the temple clasp202includes: a side plate202aabutting on the circumferential surface (cutting surface) of the lens Lm (ML) on the ear side; and a fixing plate202babutting on the rear refractive surface of the lens Lm (ML). The temple clasp203includes: a side plate203aabutting on the circumferential surface (cutting surface) of the lens Lm (MR) on the ear side; and a fixing plate203babutting on the rear refractive surface of the lens Lm (MR).

As shown inFIG. 23B, at edges of the lenses Lm (MR) and Lm (ML) on the nose side (edges facing each other), attachment holes204and205are formed. At edges of the lenses Lm (MR) and Lm (ML) on the ear side, attachment holes206and207are formed.

The left side plate201aof the bridge201is fixed to the lens Lm (ML) with a screw204sinserted through the attachment hole204, and the right side plate201bof the bridge201is fixed to the lens Lm (MR) with a screw205sinserted through the attachment hole205. Furthermore, the fixing plate202bof the temple clasp202is fixed to the lens Lm (ML) with a screw206sinserted through the attachment hole206, and the fixing plate203bof the temple clasp203is fixed to the lens Lm (MR) with a screw207sinserted through the attachment hole207. In the following description, the lenses Lm (ML) and Lm (MR) are just referred to as the lens Lm.

(II-b) Operation1; Bringing Lens Shape Feeler36into Contact with Standard Lens

When the lens holder (not shown) is detected by the holder detector53, the detection signal is inputted to the calculation control circuit52. The calculation control circuit52then causes the slider15to move forward from its origin position along the guiderail14and locate the lens shape feeler36on the outside of the circumference of the lens held by the lens holder (not shown).

Next, the calculation control circuit52causes the actuator motor50to run forward as described above and raises the lens frame feeler37from the initial position (α) to the height (β) described inFIG. 7. Along with this, the lens shape feeler36is raised integrally with the lens frame feeler37up to the height corresponding to the circumference of the lens held by the lens holder (not shown).

Subsequently, the calculation control circuit52drives and controls the driving motor18to transmit the rotation of the driving motor18to the slider15through the wire20and control and move the slider15along the guiderail14until the lens shape feeler36touches the circumferential surface of the lens Lm held by the lens holder (not shown) as shown inFIG. 18. Thereby, as shown inFIG. 18, the lens shape feeler36is brought into contact with the circumferential surface of the lens Lm.

The aforementioned control can be conducted based on data of a standard lens previously obtained by experiments and the like.

(II-c) Operation2: Bringing Lens Shape Feeler36into Contact with Lens

The procedure to bring the lens shape feeler36into contact with the circumferential surface of the lens Lm may be another one. Specifically, first, the actuator motor50is caused to run forward to raise the free end of the vertical position control lever49upward from the position inFIG. 7to the position inFIGS. 15 to 17against the spring force of the tension coil spring48, thus rotating the supporting shaft46. At this time, the supporting shaft46rotates the holding lever47to raise the free end of the holding lever47in the direction that the free end of the vertical position control lever49is raised. Along with such an operation, the engagement shaft44is raised by the spring force of the coil spring43integrally with the feeler shaft35, and the lens shape feeler36is raised and brought into contact with the rear refractive surface of the lens Lm. Thereafter, the driving motor18is driven and controlled to move the slider15along the guiderail14at a predetermined speed and move the lens shape feeler36along the rear refractive surface toward the rim of the lens Lm. The lens shape feeler36is thus moved to the position greatly deviated from the rim of the rear refractive surface of the lens Lm. At this time, even if the lens shape feeler36is separated from the rim of the rear refractive surface of the lens Lm and is raised by the spring force of the coil spring43integrally with the lens frame feeler37, it is possible to prevent the lens frame feeler37from colliding with the lens Lm by setting the moving speed of the lens shape feeler36to be fast to some extent because the spring force of the coil spring43is weak.

The separation position at which the lens shape feeler36is separated from the rear refractive surface of the lens Lm can be judged by detecting with the linear scale40the position where the lens shape feeler36is raised. The horizontal position of the lens shape feeler36located at the separation position is obtained from the detection signal of the linear scale24. Accordingly, by the detection signals from the linear scales24and40when the lens shape feeler36is located at the separation position, the position where the lens shape feeler36is separated from the rear refractive surface of the lens Lm can be calculated as three-dimensional coordinate data. Based on the three-dimensional coordinate data, the actuator motor50is driven and controlled to adjust the free end of the vertical position control lever49and therefore adjust the free end of the holding lever47, thus adjusting the lens shape feeler36to a height corresponding to the circumference of the lens Lm held by the lens holder (not shown). Thereafter, the calculation control circuit52drives and controls the driving motor18to transmit the rotation of the driving motor18through the wire20to the slider15. The slider15is then controlled and moved along the guiderail14so that the lens shape feeler36may move until touching the circumferential surface of the lens Lm held by the lens holder (not shown). Thereby, as shown inFIG. 18, the lens shape feeler36is brought into contact with the circumferential surface of the lens Lm.

(II-d) Shape Measurement of Rim by Lens Shape Feeler36

Next, the calculation control circuit52drives and controls the driving motor6to cause the driving motor6to run forward. Rotation of the driving motor6is transmitted through the pinion7and timing belt8to the driven gear5, which is then horizontally rotated integrally with the rotation base9.

Along the rotation of the rotation base9, the slider15and a number of parts provided for the slider15are horizontally rotated integrally with the rotation base9, and the lens shape feeler36slides and moves along the circumferential surface (cutting surface) of the lens Lm. At this time, the slider15moves along the guiderail14integrally with the lens frame feeler37. Accordingly, the amount of movement of the slider15from the origin position of the slider15is equal to the amount of movement of the tip of the lens frame feeler37. This amount of movement is calculated from the detection signal of the detection head26of the linear scale24by the calculation control circuit52.

Moreover, the dimension (length) between the center of the feeler shaft35and the tip of the lens frame feeler37is known. Accordingly, by previously setting the distance between the rotational center of the rotation base9and the tip of the lens frame feeler37when the slider15is located at its origin, a change in distance between the rotational center of the rotation base9and the lens shape feeler36as the slider15moves along the guiderail14can be the radius ρi.

Accordingly, by calculating the rotation angle θi of the rotation base9due to the rotation of the driving motor6from the number of driving pulses of the driving motor6and obtaining the radius ρi corresponding to the calculated rotation angle θi, the circumferential shape of the lens Lm (lens shape) can be obtained as the lens shape information (θi, ρi) in the polar coordinate system.

[Detection of Recess in Rim of Lens]

As shown inFIG. 30A, in a kind of two-point frames, a clasp303through which a temple302is attached is attached using a recess301(seeFIG. 30B) provided for the rim of a lens300. Referential numerals206and204denote attachment holes for attachment of clasps.

When such a lens is measured, the lens data includes a recess. Generally, the recess is formed in an upper half of the lens. Based on this condition, roughness due to measurement errors and the recess for attachment are distinguished to detect the position of the recess. Next, the attachment hole feeler38is moved in a lateral direction to measure a length Y of the recess in a direction toward the lens center. Alternatively, the value of the length Y can be inputted through an external input unit.

(III) Measurement of Curvature of Rear Refractive Surface of Lens Lm

When the rim shape measurement (outer shape measurement) of the lens Lm of the aforementioned inFIG. 30Bonly provides two-dimensional lens shape information (θi, ρi), three-dimensional lens shape information (θi, ρi, Zi) can be obtained by calculating by measurement the curvature of a rear refractive surface fb of the lens Lm shown inFIG. 19, and calculating the vertical position Zi of the cutting surface of the lens Lm at the two-dimensional lens shape information (θi, ρi) based on the calculated curvature and the lens shape information (θi, ρi). From the three-dimensional lens shape information (θi, ρi, Zi), the circumferential length of the lens Lm as a dummy lens in three-dimension can be calculated. Hereinafter, a description is given of a procedure of calculating the curvature of the rear refractive surface of the lens Lm.

As show inFIG. 20, in step S1, the two-dimensional lens shape information (θi, ρi) is calculated in the rim shape measurement (outer shape measurement) of the lens Lm, and then the procedure proceeds to step S2.

At step S2, the calculation control circuit52measures the curvature of the rear refractive surface fb of the lens Lm shown inFIG. 19. First, as described above, the calculation control circuit52operates and controls the actuator motor50in a similar way to the measurement of the lens frame inFIG. 30Ato bring the upper end of the lens shape feeler36into contact with the rear refractive surface fb of the lens Lm held by the not-shown lens holder with the spring force of the coil spring43.

Here, the lens Lm is held by a sucker, and the sucker is detachably attached to a not-shown lens folder, so that the lens Lm is held by the lens holder. Moreover, with the lens holder being held between the lens frames3and3, the axis line of the sucker of the lens holder vertically extending (not shown) is set so as to coincide with the axis line (an axis line O inFIG. 7) of the lens shape feeler36vertically extending when the slider15is located at its origin position. The position (point) at which these axis lines coincide with each other is set to an origin P0in the X direction (in a radial direction of the lens Lm) of the measurement.

As shown inFIG. 7, when the feeler shaft35is lowered to the lowest position and the lens frame feeler37is located at the initial position (α), the lens shape feeler36is also located at the lowest initial position. The position of the upper end (top end) of the lens shape feeler36at this time is an initial position (γ), which is set to an origin Z0of measurement in the Z direction (in the vertical direction) inFIGS. 21A and 21B.

In such conditions, the calculation control circuit52operates and controls the driving motor18to cause the slider15to move along the guiderail14through the wire20moving in cooperation with the driving motor18, thus sequentially moving the upper end (tip end) of the lens shape feeler36to measurement points P2and P1in the radial direction (X direction) of the lens Lm. The measuring point P2is located at a position to which the lens shape feeler36is moved from the origin X0in the radial direction (the X direction) of the lens Lm in the X direction by a distance X2, and the measuring point P1is located at a position to which the lens shape feeler36is moved from the origin X0in the X direction by a distance X1(X1>X2).

At this time, the calculation control circuit52respectively calculates heights Z2and Z1in the Z direction (in the vertical direction) at the distances X2and X1in the rear refractive surface fb of the lens Lm based on the movement amount detection signal from the linear scale40and proceeds to step S3. The heights Z2and Z1in the Z direction are distances from the origin Z0in the Z direction.

At step S3, the calculation control circuit52calculates a curve value from the curvature of the rear refractive surface fb of the lens Lm. Here, when the distance from the center O1of curvature of the rear refractive surface fb of the lens Lm to the origin Z0in the Z direction is ΔZ, the height from the center O1of curvature to the measurement point P2is Z2+ΔZ, and the height from the center O1of curvature to the measurement point P1is Z1+ΔZ. Accordingly, the coordinates of the measurement points P2and P1are (X2, Z2+ΔZ) and (X1, Z1+ΔZ), respectively.

To calculate the curvature from such coordinates (X2, Z2+ΔZ) and (X1, Z1+ΔZ) of the measurement points P2and P1, the calculation control circuit52uses the circle equation, which is:
X2+Z2=R2
where R is a radius of curvature of the lens Lm.

From the above equation, the equation into which the measurement point P1is substituted is:
(X1)2+(Z1+ΔZ)2=R2(1).

The equation into which the measurement point P1is substituted is:
(X2)2+(Z2+ΔZ)2=R2(2).

Subtracting the equation (2) from the equation (1) yields:
(X1)2−(X2)2+(Z1+ΔZ)2−(Z2+ΔZ)2=0.

The above equation is expanded to:
(X1)2−(X2)2+(Z1)2+2(Z1)·ΔZ+ΔZ2−(Z2)2−2(Z2)·ΔZ−ΔZ2=0.
And then,
(X1)2−(X2)2+(Z1)2+2(Z1)·ΔZ−(Z2)2−2(Z2)·ΔZ=0.

The above equation is summarized for ΔZ as:
[2(Z1)−2(Z2)]ΔZ=(X2)2−(X1)2+(Z2)2−(Z1)2.
From this equation, ΔZ can be obtained using the following equation:

The curve values of spectacle lenses are set in a range of 1 to 8 curves as shown inFIGS. 22A and 22B. Radii of curvature R1to R8for the respective curve values of 1 to 8 curves are shown in Table 1. Here, the curve values 1 to 8 may be determined as the curve value 1 is a curvature factor when the curvature radius is R1(=523 mm).

By setting X1and X2described above to 10 mm and 5 mm, respectively, the differences ΔL (ΔL1to ΔL8) between the measurement points P1and P2in the Z direction which respectively correspond to 1 to 8 curves can be obtained as shown in Table 3. In other words, when the difference ΔL between the measurement points P1and P2in the Z direction (ΔL inFIG. 21) is about 0.287, which is equal to ΔL1for example, the radius of curvature of the lens Lm as a demo lens can be determined to be 523 mm, which is R1corresponding to 1-base curve (a curve value of 1).

The relationship between the difference between the measurement points P1and P2in the Z direction (ΔL inFIGS. 21A and 21B) and a curve value Cv is expressed by linear approximation. The equation thereof is:
Curve value=3.3695×(Difference ΔLinZdirection)+0.0809.
The curve value Cv and difference ΔL (ΔL1to ΔL8) in the Z direction are linearly proportional to each other as shown inFIG. 22B.

The calculation control circuit52calculates the curve value of the rear refractive surface fb of the lens Lm in such a manner and then proceeds to step S4.

In step S4, from the curve value Cv calculated based on the difference ΔL (ΔL1to ΔL8) in the Z direction and the lens shape information (θi, ρi), the calculation control circuit52calculates Z-direction position information Zbi of the rim of the rear refractive surface fb of the lens Lm and then proceeds to step S5.

In step S5, from the two dimensional lens shape information (θi, ρi) and the Z-direction position information Zbi of the rim of the rear refractive surface fb of the lens Lm calculated in step S4, the calculation control circuit52calculates the three-dimensional lens shape information (θi, ρi, Zi) and then terminates the procedure. The calculated three-dimensional lens shape information (θi, ρi, Zi) is stored in the memory55by the calculation control circuit52.

(IV) Position Measurement of Attachment Hole of Lens Lm

As shown inFIG. 23B, the lens Lm (ML) includes the attachment holes204and206, and the lens Lm (MR) includes the attachment holes205and207.

When the lens Lm of the three-dimensional lens shape information (θi, ρi, Zi) obtained by the above measurement of (II) and (III) is the lens Lm (ML) of FIG.23B, for example, the calculation control circuit52sets attachment hole detection ranges (sensing ranges) Sa and Sb based on the three-dimensional lens shape information (θi, ρi, Zi) as shown inFIG. 24A.

The attachment hole detection ranges Sa and Sb are set a predetermined range apart from the outer circumferential surface of the lens Lm based on the three-dimensional lens shape information (θi, ρi, Zi). The predetermined range is set to a predetermined amount (for example, 1 mm) inside of the outer circumferential surface of the lens Lm. This is for preventing the attachment hole feeler38from being separated from the lens Lm. If the attachment hole feeler38is separated from the lens Lm while the attachment hole feeler38is moved in the attachment hole detection ranges Sa and Sb for detection of the attachment holes204and206, it takes a long time to return the feeler38to the original position. The value of 1 mm is just an example, and the present invention is limited to this. The point is that the attachment hole feeler38is not disengaged from the lens Lm and the attachment holes can be detected.

Thereafter, on the basis of the three-dimensional lens shape information (θi, ρi, Zi), the calculation control circuit52causes the attachment hole feeler38in contact with the rear refractive surface of the lens Lm as shown inFIG. 24Bto scan (move) in the attachment hole detection ranges Sa and Sb in a zigzag manner as indicated by arrows A1and A2for sensing of the attachment holes204and206. InFIG. 24B, the attachment hole feeler38is moved from the upper edge of the lens Lm downward in a zigzag manner. Note that, the attachment hole feeler38may be moved in a zigzag manner in the right and left direction of the lens Lm as indicated by arrows A3and A4inFIG. 24C.

Such horizontal movement of the attachment hole feeler38can be carried out by the calculation control circuit52driving and controlling the driving motor6and a pulse motor (not-shown) moving the not-shown entire base ofFIG. 2right and left. The horizontal movement position of the attachment hole feeler38is obtained as position information (θi, ρi′) composed of the rotational angle θi of the rotation base9rotated by the driving motor6and the amount of right and left movement of the aforementioned pulse motor.

Moreover, the vertical movement position of the attachment hole feeler38is obtained as Zi′ corresponding to the position information (θi, ρi′) based on the detection signal from the linear scale40. By moving the attachment hole feeler38in a zigzag manner as described above, the three dimensional position information of the attachment hole feeler38is obtained as (θi, ρi′, Zi′).

In the case where the attachment hole feeler38is moved in a zigzag manner as described above, when the attachment hole feeler38is moved in directions of arrows B1and B2as shown inFIG. 25A to 25C, for example, the attachment hole feeler38is smoothly displaced upward along the rear refractive surface of the lens Lm before and after passing the attachment hole206.

The upward movement position Zi of the attachment hole feeler38is obtained from the detection signal of the linear scale40as a vertical position change curve shown inFIG. 25D. At this time, in the vertical position change curve, in a range indicated by the arrow B1ofFIG. 25A to 25Cwhere the attachment hole feeler38moves toward the attachment hole206, the movement position Zi′ smoothly changes upward as indicated by B1′. In a range indicated by the arrow B2ofFIG. 25A to 25Cwhere the attachment hole feeler38moves from the attachment hole206, the movement position Zi′ smoothly changes upward as indicated by B2′.

When a part of the attachment hole feeler38enters the attachment hole206, as shown in the vertical position change curve ofFIG. 25D, the upward displacement of the attachment hole feeler38greatly changes at the position indicated by P.

Accordingly, the calculation control circuit52stores a central position of the position P in the memory55as the three-dimensional position information (θi, ρi′, Zi′) of the attachment hole206to produce attachment hole processing data (drilling data).

The attachment holes204,205, and207are measured in a similar manner. (C). Measurement of Lens Shape for Lens Frame (Lens Frame Shape) Larger Than Lens Frames with Average Size and Lens Shape of Lens Such as Spectacle Lens, Dummy Lens or Template

In the following description of this measurement, the lens frames LF and RF of the spectacle frame MF shown inFIG. 7and the lenses Lm (lenses ML and MR inFIGS. 23A and 23B), such as spectacle lenses or dummy lenses, shown inFIGS. 18 and 19are represented as lenses (lens shapes) SL and SR as shown inFIG. 32.

The feelers36and37used for measuring the lenses (lens shapes) SL and SR are rotatable by means of the driven gear5shown inFIGS. 2 to 5Aas described above.

Specifically, the driven gear5inFIGS. 2 to 5Ahas the rotational center O5shown inFIG. 5B. The rotation base9is integrally provided to the driven gear5. The rotational center O5of the driven gear5serves as the rotation axis line of the rotation base9. The rotational center O5extends in the vertical direction.

In addition, as described above, the horizontal movement of the slider15guided by the guide rail14causes the feeler shaft35and the feelers36and37to move forward and backward in the radial direction relative to the rotational center O5shown inFIG. 5B, which is also the rotation axis lines of the driven gear5and the rotation base9. Note that the amount of the forward and backward movement of the feeler shaft35and the feelers36and37in the radial direction varies depending on the length of the guide rail14, the size of the slider15, and the like. The maximum moving amount Smax of the feeler shaft35and the feelers36and37in the radial direction are predetermined.

(i) The necessity of extended measurement is determined by driving, in advance, the feeler independently in an X direction toward a point which is likely to be out of the moving radius of the feeler to check the radius length.

In this determination, the calculation control circuit52executes movement control of the feelers36and37by drive controlling drive units such as the driving motors6and18, and the actuator motor50, as in (B) Measurement on Average-sized or Ordinary Lens Shape as described above.

Specifically, the calculation control circuit52executes the movement control in the following manner.The radius length rρR (or rρL) from the center of measurement ScR (or ScL) of the lens (lens shape) SR (or SL) to a point PaR (or PaL) which is likely to be beyond the stroke of the corresponding feeler36or37in measurement is checked in a way that, before the start of the ordinary lens shape measurement, the feelers36and37are independently driven for movement in the XR direction (or the XL direction) which is the X direction toward the point PaR (or PaL) by a distance XaR (or XaL) (refer toFIG. 32). Here, the center of measurement ScR (or ScL) is also the rotational center O5of the rotation base9.By independently driving the feelers36and37only in the XR direction (or the XL direction) for the check, the distance from an imaginary line X passing through the rotational center O5of the rotation base9to the point PaR (or PaL) is read as a measurement value ρyR (or ρyL). On the basis of the measurement value ρyR (or ρyL), the distance from the center of measurement ScR (or ScL) to the feeler36or37(pattern sensor) is converted into the radius length rρR (or rρL). The distance may be that from the center of measurement ScR (or ScL) to the center of the feeler36or37(pattern sensor).When the feelers36and37are moved in the XR direction (or the XL direction) maximally to a point of reverse where the radius length rρR (or rρL) reaches its maximum (the maximum moving amount Smax), the radius ρi goes beyond the stroke (the maximum moving amount Smax) of the feelers36and37in measurement in the half way. This corresponds to an error, and thus it is determined to execute the extended measurement.When no point of reverse as described above is detected during the movement of the feelers36and37in the XR (or XL) direction, the feelers36and37are maximally moved by a distance XaR (or XaL), which allows an ordinary measurement.The movement of the feelers36and37in the XR (or XL) direction is set so that the directions of the movement for left and right lenses SR and SL, respectively, can be opposite to each other (refer toFIG. 32). In this case, the measurement rotation direction of the feelers36and37centered at the rotational center O5is not limited to the clockwise direction (CW) only or the counterclockwise direction (CCW) only. The direction may be the clockwise direction (CW) or the counterclockwise direction (CCW).After completion of such search, the feelers36and37are returned to a starting point of measurement.If the radius rρR (or rρL) is beyond the stroke of the feeler in measurement, the procedure proceeds to the extended measurement sequence.If the radius rρR (or rρL) is within the stroke of the feeler in measurement, the ordinary measurement is continued.

Here, for the lens SR,
rρR=√{square root over ((ρyR)2+(XaR)2)}{square root over ((ρyR)2+(XaR)2)}
where

a distance moved from the center of measurement is XaR,

a value read from an SLIDC (the linear scale24) is ρyR, and

the distance from the center of measurement to the center of the pattern sensor is rρR.

Meanwhile, for the lens SL,
rρL=√{square root over ((ρyL)2+(XaL)2)}{square root over ((ρyL)2+(XaL)2)}
where

a distance moved from the center of measurement is XaL,

a value read from the SLIDC (the linear scale24) is ρyL, and

the distance from the center of measurement to the center of the pattern sensor is rρL.

When a shorter measurement time is required, such processes for determining and setting a measurement region can be omitted.

(ii) The necessity of the extended measurement is determined by detecting the excess of the moving radius limit (measurement limit) value for the feeler during an ordinary measurement.

Judgment whether to divide the measurement region into multiple pieces or a plurality of sub-regions may be made on the basis of measurement on the lens SL (or SR), in stead of the measurement of the point as in item (i). These measurement and determination (judgment) are made first on the right lens SR.

Specifically, in Step S10ofFIG. 33, the calculation control circuit52places the rotational center O5of the feelers36and37at the initial position for the measurement by drive controlling the driving motor6, the driving motor18, the actuator motor50, and the like as described above. Thereafter, the calculation control circuit52rotates the rotation base9about the rotational center (vertical axis line) O5in a horizontal direction by drive controlling the driving motor6so as to start the measurement of the lens shape of the lens (lens shape) SR using the feelers36and37. Then, the procedure proceeds to Step S11.

In this Step S11, the calculation control circuit52starts to acquire lens shape data (θi, ρi) by measuring radii ρi (i=0, 1, 2, . . . n) with respect to the rotation angles (angles) θi (i=0, 1, 2, . . . n) of the rotation base9about the rotational center (vertical axis line) O5by using the linear scale24.

In this step, for measurement of the lens shape for the lens frame RF, which corresponds to the spectacle lens shape SR, the lens frame feeler37is brought into contact with the inner peripheral surface of the lens frame RF, which corresponds the spectacle lens shape SR. With this contact state being kept, the lens frame feeler37is moved in the circumferential direction of the lens frame RF along the inner peripheral surface (contact surface with the lens) of the lens frame RF, to thereby start the measurement of the lens shape represented by radii μi (i=0, 1, 2, . . . n) with respect to rotation angles θi. Here, the radii ρi (i=0, 1, 2, . . . n) represent change in distance from the geometric center of the lens frame shape (lens shape) of the lens frame RF, which corresponds to the lens shape, to the lens frame feeler37.

Meanwhile, in this step, for measurement of a lens shape of the lens Lm (the lens MR inFIGS. 23A and 23B) such as a spectacle lens, a dummy lens, or a template, corresponding to the spectacle lens SR, the lens shape feeler36is brought into contact with the outer peripheral surface of the lens Lm (the lens MR inFIGS. 23A and 23B). With this contact state being kept, the lens shape feeler36is moved in the circumferential direction of the lens Lm (the lens MR inFIGS. 23A and 23B) along the outer peripheral surface (contact surface with the lens) of the lens Lm, to thereby start the measurement of a lens shape (lens) represented by radii ρi with respect to the rotation angles θi. Here, the radii ρi (i=0, 1, 2, . . . n) represent change in distance from the geometric center of the lens shape of the lens Lm (the lens MR inFIGS. 23A and 23B) to the lens shape feeler36.

As described above, the calculation control circuit52starts to acquire lens shape data (θi, ρi) of the lens SR, and proceeds to Step S12.

Then, on the basis of the lens shape data (θi, ρi) acquired in Step S11, the calculation control circuit52determines whether the entire circumferential measurement region of the lens (lens shape) SR has a point where the radius ρi exceeds the maximum moving amount Smax of the corresponding feeler36or37in the radial direction (i.e., the point is beyond the stroke of the feeler). In this determination, if the radius ρi does not exceed the maximum moving amount Smax of the corresponding feeler36or37in the radial direction (i.e., the radius ρi is within the reach of the feeler), the calculation control circuit52proceeds to Step S13. In this determination, if the radius ρi exceeds the maximum moving amount Smax of the corresponding feeler36or37in the radial direction (i.e., the radius ρi is beyond the stroke of the feeler), the calculation control circuit52proceeds to Step S14.

In this Step S13, the calculation control circuit52judges whether or not the acquired lens shape data (θi, ρi) of the lens SR covers the entire circumference of the lens SR.

If the acquired lens shape data (θi, ρi) of the lens SR does not cover the entire circumference of the lens SR, the calculation control circuit52returns to Step S10and repeats the processing.

If the lens shape data (θi, ρi) of the lens SR acquired in Step S13covers the entire circumference of the lens SR, the calculation control circuit52terminates the ordinary measurement.

(III). As a result of the necessity determination of the extended measurement in item (i) or (ii) as described above, if it is determined that the extended measurement is necessary, the calculation control circuit52executes the extended measurement sequence shown inFIG. 34.
Step S14

Then, on the basis of this measurement, if determining that there is a measurement point where the radius ρi exceeds the maximum moving amount Smax of the corresponding feeler36or37in the radial direction (i.e., the radius ρi is beyond the stroke of the feeler), the calculation control circuit52divides the measurement region into a first region (first measurement region) and a second region (second measurement region). In the first region, the radii ρi do not exceed the maximum moving amount Smax of the corresponding feeler36or37in the radial direction. In the second region, the radii ρi exceed the maximum moving amount Smax of the corresponding feeler36or37(i.e., the radius ρi is out of the moving radius of the feeler).

Thereafter, in the first region, while the rotation axis line (rotational center O5) is positioned at the initial measurement position, which is a first position, the radii ρi are measured. Meanwhile, in the second region, the rotation axis line (rotational center O5) is moved from the initial measurement position to a second position which allows measurement within the maximum moving amount Smax by the corresponding feeler36or37, and then the radii ρi of the lens are measured.

The calculation control circuit52executes such determination whether to divide the entire circumferential measurement region of the lens into the first and second regions, and determination of and control for measurement of the lens in the first and second regions.

Specifically, the lens shape is measured, while the measurement regions are set as shown inFIG. 34. Sections X1, X2, X3, and X4(extended measurement area) where the feeler is driven only in the X direction for measurement as shown inFIG. 34are interposed, in order to compensate the shortage of the measurement reach of the prove in the A size direction (X direction) of the lens SR.FIG. 34shows a case where the measurement is performed in counter clockwise (CCW) direction.

(a). The rotational center O5is moved in the X axis direction from the center of an ordinary measurement Oc to the position (−X_wide/2), i.e., (R1) which is closer to the X origin inFIG. 34than the center of an ordinary measurement Oc by a half of an extended measurement width X_wide.
(b). With the rotational center O5being at the position of (−X_wide/2) i.e., (R1), the rotation base9is rotated about the rotational center O5, and the lens SR is measured by using the corresponding feeler36or37in the polar coordinate system within the range of 180 degrees.
(c). For the sections X1and X2(extended measurement area), axial rotation of the rotation base9about the rotational center O5is stopped, and the upper side of the lens SR within the range of the extended measurement width (X_wide) is measured by using the feeler36or37.

The slider15is moved by an X motor (the driving motor18) at intervals of 0.02 mm, which is the minimum interval, to thereby measure radii (radius data) of the lens SR within the sections X1and X2(on the upper side of the lens SR) by using the feeler36or37.

(d). The rotational center O5is moved in the X axis direction from the center of the ordinary measurement Oc to the position (−X_wide/2), i.e., (R2) which is more distant from the X origin inFIG. 34than the center of an ordinary measurement Oc by a half of an extended measurement width X_wide. With the rotational center O5being at the position of (−X_wide/2), the rotation base9is rotated about the rotational center O5, and the lens SR is measured by using the feeler36or37in the polar coordinate system within the range of the other 180 degrees.
(e). For the sections X3and X4(extended measurement area), the axial rotation of the rotation base9about the rotational center O5is stopped, and the lower side of the lens SR within the range of the extended measurement width (X_wide) is measured by using the feeler36or37.
[Processing of Radii (Radius Data) Acquired in Extended Measurement]

The calculation control circuit52executes the processing of the radii (radius data) thus acquired in items (a) to (e) in accordance with the following procedure.

difference in axis between the polar coordinate system and the absolute coordinate system: X_mtr_axis [degrees]

(1-1). The acquired row radius data (ρ data) is converted into data centered at a pattern stylus center position.
ρ=>ρstrs
(1-2). the ρ data obtained by the polar coordinate measurement is converted into the X, Y coordinates.
(ρstrs, θ)=>(x, y)
(1-3). the X Y coordinates converted from the ρ data obtained by the polar coordinate measurement are converted into data centered at the center of the ordinary measurement.
x coordinate correction amount:
Δx=x_wide/2*1000*x_mtr_linia
y coordinate correction amount:
Δy=tan(X_mtr_axis)*ΔX

(1-4). The radius data obtained by the extended area measurement is converted into data centered at the center of the ordinary measurement.
(X, ρstrs)=>(x′, y′)

The extended measurement area is divided into sections.

(1-5). The number of measurement points which is larger than those for the ordinary measurement because of the extended measurement is converted to the number 6000 which is the number of points of the ordinary measurement.

(1-6). Calculation processing after the conversion to the ordinary point number 6000 is the same as in the ordinary measurement.

In the aforementioned embodiment, as shown inFIG. 23B, the bridge201includes the fixing plates201cand201dwhich abut on the rear refractive surfaces of the lenses Lm (ML) and Lm (MR), respectively; and the temple clasps202and203include the fixing plates202band203bwhich respectively abut on the rear refractive surfaces of the lenses Lm(ML) and Lm(MR) as shown inFIG. 23B. However, the present invention is not necessarily limited to this.

For example, as shown inFIGS. 26A and 26B, the spectacle frame may have a configuration in which the fixing plates201cand201drespectively abut on front refractive surfaces of the lenses Lm (ML) and Lm (MR) and the temple clasps202and203include the fixing plates202bad203babutting on the front refractive surfaces of the lenses Lm (ML) and Lm (MR), respectively as shown inFIG. 26B.

In this case, the curvature of the front refractive surfaces of the lenses Lm (ML) and Lm (MR) and the circumferential length of the cutting surfaces of the lenses Lm (ML) and Lm (MR) are measured in a similar manner to the rear refractive surfaces of the aforementioned lenses Lm, and the positions of the attachment holes204to207are measured.

Note that, inFIGS. 26A and 26B, the same or similar components to those ofFIGS. 23A and 23Bare given the same reference numbers used inFIGS. 23A and 23B, and the description thereof is omitted.

In the aforementioned embodiment, the attachment hole detection ranges (sensing ranges) Sa and Sb extending in the vertical direction of the lens Lm are set in the right and left parts of the lens Lm, but the present invention is not necessarily limited to this. For example, as shown inFIG. 27, a margin line311for measurement for preventing the attachment hole feeler from being separated from the lens is set a predetermined amount (for example, 1 mm) inside of an outer circumferential surface310of the lens Lm based on the lens shape information (θi, ρi, Zbi), and an attachment hole detection range (a sensing range) Sc of a predetermined range (for example, 10 mm×10 mm) is set.

Then, as shown inFIG. 28, a number of measurement points Pi (for example, 200 points in a matrix) are provided in the attachment hole detection range (sensing range) Sc, and three dimensional position information of the refractive surface of the lens Lm is measured at the 200 measurement points Pi in a matrix by the attachment hole feeler38. At this measurement, the position where the attachment hole feeler38is largely displaced upward in the attachment hole detection range (sensing range) Sc is detected from the detection signal from the linear sensor40as the position of an attachment hole. The detected position is stored in the memory55as the three-dimensional position information (θi, ρi′, Zi′) to produce the attachment hole processing data (drilling data).

Typically, the positions in the lens Lm where the attachment holes204to207and the like are provided are in upper right or left side of the lens Lm or at a central portion of the right or left side of the lens Lm in the vertical direction. Accordingly, a switch for selecting a detection position such as upper part or central part in the height direction of the right and left sides of the lens Lm is provided, and based on the detection position selected by the switch and the lens shape information (θi, ρi, Zbi), the attachment hole detection range (sensing range) Sc is set.

Moreover, as shown inFIG. 29, a shape220of the lens Lm is displayed based on the lens shape information (θi, ρi, Zbi) on a touch screen liquid crystal display221, and a position indicated by a cross mark222is indicated through a touch screen of the liquid crystal display221, for example, as a rough position of the attachment holes204to206or the like. The aforementioned attachment hole detection range (sensing range) Sc can be set based on the indicated position.

As described above, the lens shape measuring apparatus of this embodiment of the present invention includes: a lens holding unit (not shown) provided within the measuring apparatus body1; a lens shape feeler36measuring the rim shape of the lens Lm held by the lens holding unit (not shown); a feeler moving unit (driving motor6) moving the lens shape feeler36along the outer circumferential surface of the lens Lm; a first position detector (linear scale24) detecting the position of the lens shape feeler36along the outer circumferential surface; a second position detector (linear scale40) detecting the position of the lens shape feeler36in a direction perpendicular to the first detector (linear scale24); and a calculation control circuit52calculating the circumferential surface shape data of the lens Lm as the three dimensional information on the basis of the detection signals from the first and second position detectors (linear scales24and40). Moreover, using (controlling) the feeler moving unit (driving motor6), the tip end of the lens-shape feeler36is moved while abutting on the refractive surface of the lens Lm held by the lens holding unit (not shown). Thereby, a change due to engagement of the lens-shape feeler36with the attachment holes (204to207) of the lens Lm is detected from the detection signal of the second position detector (linear scale40). Based on the change, the relationship between the lens rim shape and the hole position is detected.

According to such a configuration, it is possible to easily and accurately measure the positions of attachment holes through which clasps of a two-point frame are attached to lenses.

Moreover, the lens shape measuring apparatus of this embodiment of the present invention is configured to detect a position of a recess of a lens including a clasp attachment hole and including a recess in the rim from the circumferential shape of the lens.

According to this configuration, it is possible to provide a recess in the periphery of the lens and attach the clasp of the two-point frame using the recess.

Furthermore, the feeler of the lens shape measuring apparatus of this embodiment of the present invention which detects a clasp attachment hole of the lens may be composed of a different member from the feeler measuring the circumferential shape.

According to this configuration, the feeler detecting a clasp attachment hole of a lens (attachment hole feeler38) and the lens shape feeler36can be easily processed.

InFIGS. 31A and 31B, a flame holding section includes multiple skids, and the skids are rolled on a guiderail to swing the frame holding section.

InFIG. 31A, multiple skids421are provided for a frame holding section420and are configured to roll right and left on a guiderail422having a concaved upper surface. The upper surface of the guiderail422is formed in an inverted cylindrical shape, thus allowing the frame holding section420to swing in directions of arrows E1and E2around a virtual axis423which is located away from the measuring apparatus body (above the measuring apparatus body).

Here, reference numeral424denotes a feeler measuring the shape of a spectacle frame425. The spectacle frame425is set within the frame holding section420and held at a distance R1from the virtual axis423.

InFIG. 31B, multiple skids431are provided for a frame holding section430and are configured to roll right and left on a guiderail432having a convex upper surface. The upper surface of the guiderail432is formed in a cylindrical shape, thus allowing the frame holding section430to swing in directions of arrows F1and F2around a virtual axis433which is located away from the measuring apparatus body (below the measuring apparatus body).

Here, reference numeral434denotes a feeler measuring the shape of a spectacle frame435. The spectacle frame435is set within the frame holding section430and held at a distance R2from the virtual axis433.

According to a lens shape measuring method and a lens shape measuring apparatus of an embodiment of the present invention, it can be achieved to provide a lens shape measuring method and a lens shape measuring apparatus capable of measuring a large lens shape without enlargement in size of the apparatus as a whole.

Although the present invention has been described in terms of exemplary embodiments, it is not limited thereto. It should be appreciated that variations may be made in the embodiments described by persons skilled in the art without departing from the scope of the present invention as defined by the following claims.