Abrégé

A machining method using a spherical center-type machining apparatus (1) comprises: a tool attachment step (ST1) for causing a lens holder (41) to hold a lens material (40) and attaching a machining tool (5) to a spindle (6); a first spherical surface machining step (ST2) for performing a spherical surface machining operation; a first difference acquisition step (ST3) for acquiring a first machining radius (R1) of a machining-target surface (40a) of the lens material (40) and acquiring a first difference (∆R1) between a target radius (Re) and the first machining radius (R1); a first tool position setting step (ST4) for defining, as the target radius (Re), the distance between a first contact point (C1), at which the tool surface (5a) of the machining tool (5) is in contact with the machining-target surface (40a), and an intersection point (O) of a rotation axis (L1) and an oscillation axis (L2), by moving the machining tool (5) by a distance corresponding to the first difference (∆R1); and a second spherical surface machining step (ST5) for causing the lens holder (41) to hold a new lens material (40) to perform the spherical surface machining operation.

Classes IPC  ?

• B24B 13/02 - Machines ou dispositifs conçus pour meuler ou polir les surfaces optiques des lentilles ou les surfaces de forme similaire d'autres piècesAccessoires à cet effet au moyen d'outils possédant des surfaces abrasives dont la forme correspond à la forme de la lentille à travailler
• B24B 49/02 - Appareillage de mesure ou de calibrage pour la commande du mouvement d'avance de l'outil de meulage ou de la pièce à meulerAgencements de l'appareillage d'indication ou de mesure, p. ex. pour indiquer le début de l'opération de meulage comparant la cote instantanée de la pièce travaillée à la cote cherchée, la mesure ou le calibrage étant continus ou intermittents

Abrégé

In a spherical lens surface processing method, a lens surface is ground to a spherical surface by forming a contact state in which a rotating cup-shaped grinding stone is placed in contact with the lens surface and a sphere center oscillation state in which the cup-shaped grinding stone oscillates along the lens surface centered on a sphere center. In the sphere center oscillation state, the distance from the center of the sphere center oscillation to the contact point of the cup-shaped grinding stone with the lens surface is set to be the same as the radius of the spherical surface. The oscillation width of the sphere center oscillation is set so that the contact point of the cup-shaped grinding store with the lens surface can move from one peripheral edge of the lens surface past the lens center on the lens surface to the other peripheral edge.

Classes IPC  ?

• B24B 13/04 - Meulage de lentilles, faisant intervenir des meules commandées par des engrenages
• B24B 13/02 - Machines ou dispositifs conçus pour meuler ou polir les surfaces optiques des lentilles ou les surfaces de forme similaire d'autres piècesAccessoires à cet effet au moyen d'outils possédant des surfaces abrasives dont la forme correspond à la forme de la lentille à travailler

Abrégé

In a spherical lens surface processing method, a lens surface (5a) is ground to a spherical surface by forming a contacting state in which a rotating cup-shaped grinding stone (9) is placed in contact with the lens surface (5a) and a sphere center oscillation state in which the cup-shaped grinding stone (9) oscillates along the lens surface (5a) centered on a sphere center. In the sphere center oscillation state, the distance from the center (P1) of the sphere center oscillation to the contact point (P3) of the cup-shaped grinding stone (9) with the lens surface (5a) is set to be the same as the radius (R) of the spherical surface. The oscillation width of the sphere center oscillation is set so that the contact point (P3) of the cup-shaped grinding stone (9) with the lens surface (5a) can move from one peripheral edge of the lens surface (5a) past the lens center (P2) on the lens surface to the other peripheral edge.

Classes IPC  ?

• B24B 13/04 - Meulage de lentilles, faisant intervenir des meules commandées par des engrenages
• B24B 13/02 - Machines ou dispositifs conçus pour meuler ou polir les surfaces optiques des lentilles ou les surfaces de forme similaire d'autres piècesAccessoires à cet effet au moyen d'outils possédant des surfaces abrasives dont la forme correspond à la forme de la lentille à travailler

Abrégé

According to this lens-centering method, a state in which a lens is sandwiched at prescribed pressing force between a lens holder and a lens processing dish is brought about. Next, the lens-processing dish is rotated at slow speed about a rotation axis line that passes through the center and the spherical center of the lens-processing surface thereof, and is made to oscillate at a slight angle about the spherical center of the lens-processing surface as the center of oscillating action. The spherical center of a first lens spherical surface of the lens is guided to the spherical center of a lens-retaining surface of the lens holder, and the spherical center of a second lens spherical surface is guided to the spherical center of the lens-processing surface. A lens mounted in the spherical center-type processing machine can be set to an accurately centered state thereby.

Classes IPC  ?

• B24B 13/02 - Machines ou dispositifs conçus pour meuler ou polir les surfaces optiques des lentilles ou les surfaces de forme similaire d'autres piècesAccessoires à cet effet au moyen d'outils possédant des surfaces abrasives dont la forme correspond à la forme de la lentille à travailler
• B24B 13/005 - Dispositifs de blocage, supports ou similairesDispositifs d'alignement
• B24B 51/00 - Systèmes pour la commande automatique d'une série d'opérations successives du meulage d'une pièce

Abrégé

　According to this lens-centering method, a state in which a lens (7) is sandwiched at prescribed pressing force between a lens holder (4) and a lens processing dish (8) is brought about (steps ST1-3). Next, the lens-processing dish (8) is rotated at slow speed about a rotation axis (8A) that passes through the center (C) (8a) and the spherical center (O) (8a) of the lens-processing surface (8a) thereof, and is made to oscillate at a slight angle about the spherical center (O) (8a) of the lens-processing surface (8a) as the center of oscillating action. The spherical center of a first lens spherical surface (7a) of the lens (7) is guided by the spherical center of a lens-retaining surface (4a) of the lens holder (4), and the spherical center of a second lens spherical surface (7b) is guided by the spherical center (O) (8a) of the lens-processing surface (8a) (rotation/oscillation step ST4). A lens installed in the spherical center-type processing machine can be set to an accurately centered state thereby.

Classes IPC  ?

• B24B 13/02 - Machines ou dispositifs conçus pour meuler ou polir les surfaces optiques des lentilles ou les surfaces de forme similaire d'autres piècesAccessoires à cet effet au moyen d'outils possédant des surfaces abrasives dont la forme correspond à la forme de la lentille à travailler

Abrégé

A spherical core type lens grinding device (1) performs an operation wherein a dish-shaped grindstone (8) provided with a spherical grindstone surface (8a) which is equipped with diamond abrasive grains, is pressed against a surface-to-be-ground (7a) of a lens blank (7) to be ground, and wherein the dish-shaped grindstone (8) is rotated and is simultaneously swung, resulting in said surface-to-be-ground (7a) being ground to a spherical surface. In an initial-stage grinding process, grinding is performed at first processing pressure and first rotational speed. In an intermediate-stage grinding process, grinding is performed at second processing pressure and second rotational speed. In a last-stage grinding process, grinding is performed at third processing pressure and third rotational speed. The second processing pressure is a pressure at which the spherical grindstone surface (8a) can bite into the lens blank (7). The biting amount of the dish-shaped grindstone (8) is obtained from the hardness of the lens blank (7) and the contact area between the surface-to-be-ground (7a) and the spherical grindstone surface (8a). The second processing pressure is calculated from the biting amount thus obtained. A coarse grinding process and a precision grinding process are unified into a single process. Therefore, the surface of the lens blank can be ground to a spherical surface by using only a dish-shaped grindstone used for precision grinding.

Classes IPC  ?

• B24B 13/04 - Meulage de lentilles, faisant intervenir des meules commandées par des engrenages

Abrégé

A lens processing device (1) is adapted such that a lens (11) is sucked and held by a lens holder (12) rotatably and rockably supported on the front end of a lens holder shaft (13) through a pivot bearing mechanism (14) and then such that a lens surface (11a) is processed by moving the lens (11) and a lens processing tool (31) relative to each other with the lens processing tool (31) pressed to the lens (11).  The lens (11) can be moved along a desired trajectory on a vertical plane containing a Z-axis and an X-axis, which are perpendicular to each other, by controlling feeding of the lens holder (12) in the Z-axis and X-axis directions by means of a Z-axis movement mechanism (19) and an X-axis movement mechanism (15).  Thus, the lens surface (11a) can be processed with the lens (11) horizontally pressed to a circular arc-shaped processing surface (31a) of the lens processing tool (31).

Classes IPC  ?

• B24B 13/02 - Machines ou dispositifs conçus pour meuler ou polir les surfaces optiques des lentilles ou les surfaces de forme similaire d'autres piècesAccessoires à cet effet au moyen d'outils possédant des surfaces abrasives dont la forme correspond à la forme de la lentille à travailler