DIAPHRAGM POSITION MEASURING METHOD, DIAPHRAGM POSITION MEASURING APPARATUS, DIAPHRAGM POSITIONING METHOD AND DIAPHRAGM POSITIONING APPARATUS
A diaphragm position measuring method and a diaphragm position measuring apparatus are disclosed, which are capable of measuring a deviation quantity between a center of an optical diaphragm and an optical axis with high accuracy. A diaphragm positioning method and a diaphragm positioning apparatus are further disclosed, which are capable of disposing the optical diaphragm in a lens unit with the high accuracy. A light condensing spot is formed by getting a collimated beam of light incident upon lenses of the lens units supported on a glass sheet, and a position of the light condensing spot, if detected by a microscope, can be used as a reference point for positioning the optical diaphragm. A central processing unit can obtain a deviation quantity between the position of the light condensing spot and a central position of the optical diaphragm, which is acquired by the microscope, and the lens unit can be effectively inspected by use of a result thereof. It is thereby feasible to detect the deviation quantity of the central position of the optical diaphragm with an error equal to or smaller than ±3 μm.
1 . A diaphragm position measuring method of measuring a position of an optical diaphragm in a lens unit including the optical diaphragm, lenses and a mirror frame holding the optical diaphragm and the lenses, the method comprising:
a step of forming a light condensing spot by getting a collimated beam of light parallel with an optical axis of the lenses incident upon the lenses of the lens unit;
a step of detecting a position of the light condensing spot;
a step of detecting a central position of the optical diaphragm; and
a step of obtaining a deviation quantity between the position of the light condensing spot and the central position of the optical diaphragm.
2 . The diaphragm position measuring method according to claim 1 , wherein the step of detecting the central position of the optical diaphragm involves obtaining geometrically the central position of the optical diaphragm from a shape of an inside diameter of the optical diaphragm.
3 . A diaphragm position measuring apparatus of measuring a position of an optical diaphragm in a lens unit including the optical diaphragm, lenses and a mirror frame holding the optical diaphragm and the lenses, the apparatus comprising:
a support base including at least a portion as a transmitted portion that can be penetrated by the light and supporting the lens unit in superposition on the transmitted portion;
a light irradiation device irradiating the lens unit with the collimated beam of light parallel with the optical axis of the lenses of the lens unit;
first detecting means detecting a position of the light condensing spot formed when the collimated beam of light penetrates the lenses of the lens unit;
second detecting means detecting the central position of the optical diaphragm; and
arithmetic means obtaining a deviation quantity between the detected position of the light condensing spot and the central position of the optical diaphragm.
4 . The diaphragm position measuring apparatus according to claim 3 , further comprising a Z-directional moving stage moving the first detecting means and/or the second detecting means and the support base relatively in a collimated beam emitting direction.
5 . The diaphragm position measuring apparatus according to claim 3 or 4 , further comprising:
an XY-directional moving stage moving the first detecting means and/or the second detecting means and the support base relatively in a direction orthogonal to the collimated beam emitting direction; and
moving quantity detecting means detecting a moving quantity of the XY-directional moving stage.
6 . The diaphragm position measuring apparatus according to any one of claims 3 to 5 , further comprising a tilt stage tilting the light irradiation device and the support base relatively in the collimated beam emitting direction.
7 . The diaphragm position measuring apparatus according to claim 6 , further comprising tilt detecting means detecting a relative tilt of the support base to the collimated beam of light.
8 . The diaphragm position measuring apparatus according to any one of claims 3 to 7 , wherein a light reduction member is inserted in between the first detecting means and the support base.
9 . The diaphragm position measuring apparatus according to any one of claims 3 to 8 , wherein the first detecting means serves also as the second detecting means.
10 . An optical diaphragm positioning method of positioning an optical diaphragm with respect to a lens unit including lenses and a mirror frame holding the lenses, the method comprising:
a step of forming a light condensing spot by getting a collimated beam of light parallel with an optical axis of the lenses incident upon the lenses of the lens unit;
a step of holding the optical diaphragm in the lens unit in a way that temporarily positions the optical diaphragm;
a step of detecting a central position of the optical diaphragm;
a step of shifting the optical diaphragm so that the central position of the optical diaphragm is coincident with the position of the light condensing spot; and
a step of fixing the optical diaphragm to the lens unit when the central position of the optical diaphragm becomes coincident with the position of the light condensing spot.
11 . The optical diaphragm positioning method according to claim 10 , wherein the step of detecting the central position of the optical diaphragm involves obtaining geometrically the central position of the optical diaphragm from a shape of an inside diameter of the optical diaphragm.
12 . An optical diaphragm positioning apparatus for positioning an optical diaphragm with respect to a lens unit including lenses and a mirror frame holding the lenses, the apparatus comprising:
a support base including at least a portion composed of a material that can be penetrated by the light and supporting the lens unit;
a holding member holding the optical diaphragm in the lens unit in a way that temporarily positions the optical diaphragm;
a light irradiation device irradiating the lens unit with a collimated beam of light parallel with an optical axis of the lenses of the lens unit;
first detecting means detecting a position of the light condensing spot formed when the collimated beam of light penetrates the lenses of the lens unit;
second detecting means detecting a central position of the optical diaphragm; and
a driving device shifting the holding member together with the optical diaphragm so as to decrease a deviation quantity between the detected position of the light condensing spot and the central position of the optical diaphragm.
13 . The optical diaphragm positioning apparatus according to claim 12 , further comprising a Z-directional moving stage moving the first detecting means or the second detecting means and the support base relatively in a collimated beam emitting direction.
14 . The optical diaphragm positioning apparatus according to claim 12 or 13 , further comprising:
an XY-directional moving stage moving the first detecting means or the second detecting means and the support base relatively in a direction orthogonal to the collimated beam emitting direction; and
moving quantity detecting means detecting a moving quantity of the XY-directional moving stage.
15 . The optical diaphragm positioning apparatus according to any one of claims 12 to 14 , further comprising a tilt stage tilting the light source and the support base relatively in the collimated beam emitting direction.
16 . The optical diaphragm positioning apparatus according to claim 15 , further comprising tilt detecting means detecting a relative tilt of the support base to the collimated beam of light.
17 . The optical diaphragm positioning apparatus according to any one of claims 12 to 16 , wherein a light reduction member is inserted in between the first detecting means and the support base.
18 . The optical diaphragm positioning apparatus according to any one of claims 12 to 17 , wherein the first detecting means serves also as the second detecting means.