Alignment verification system for use with interferometer and having a line sensor

• US 5,471,305 A
• Filed: 07/22/1994
• Issued: 11/28/1995
• Est. Priority Date: 07/23/1993
• Status: Expired due to Fees

• Current Assignee: Fuji Photo Optical Co. Ltd (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Photo Optical Co. Ltd (Fujifilm Holdings Corporation)
• Inventors: Akaogi, Toshikazu, Yoneda, Masami
• Primary Examiner(s): Turner, Samuel A.
• Assistant Examiner(s): KIM, ROBERT H
• Application Number:
  US08/278,842
• Time in Patent Office: 494 Days
• Field of Search: 356/345, 356/363, 356/359, 356/360
• US Class Current: 356/508
• CPC Class Codes: G01B 11/306 for measuring evenness
• CPC Class Codes: G01B 9/02072 by calibration or testing of interferometer

Abstract

An alignment verification system for adjusting the posture of a test piece on a support table into alignment with a reference plate on an interferometer containing a light source to irradiate the test piece and reference plate, the verification system including: a bi-axial adjustment means for tilting the support table in the directions of perpendicularly intersecting X- and Y-axis; spot image forming means arranged to converge light reflections from a master surface of the reference plate and an inspecting surface of the test piece into spot images of a predetermined diameter at a predetermined spot image-forming plane; a line sensor located at the spot image-forming plane across the spot image of the reference plate and having a linear light receiving face switchable through 90° between an X-axis position and a Y-axis position corresponding to the directions of the X- and Y-axes of the bi-axial adjustment means, for detecting the spot image of the test piece in relation with tilting adjustments of the support table by the bi-axial adjustment mechanism in each of the X- and Y-axis positions; and a sensor drive mechanism adapted to switch the light receiving face of the line sensor from the X-axis position to the Y-axis position or vice versa upon detecting the spot image of the test piece in one of the X- and Y-axis positions.

Claims

1. An alignment verification system for adjusting the posture of a test piece on a support table into alignment with a reference plate on an interferometer including a light source to irradiate said test piece and reference plate, said verification system comprising:

a bi-axial adjustment means for tilting said test piece on said support table in the directions of perpendicularly intersecting X- and Y-axis;

spot image forming means arranged to converge light reflections from a master surface of said reference plate and an inspecting surface of said test piece into spot images of a predetermined diameter at a predetermined spot image-forming plane;

a line sensor located at the spot image-forming plane across the spot image of the reference plate and having a linear light receiving face arranged to be switchable through 90°

between an X-axis position and a Y-axis position corresponding to the directions of said X- and Y-axes of said bi-axial adjustment means, for detecting the spot image of said test piece in relation with tilting adjustments of said support table by said hi-axial adjustment mechanism in each of said X- and Y-axis positions; and

a sensor drive mechanism adapted to switch said light receiving face of said line sensor from said X-axis position to said Y-axis position or vice versa upon detecting said spot image of said test piece in one of said X- and Y-axis positions.

2. An alignment verification system as defined in claim 1, wherein said line sensor is supported on a rotational shaft for rotation about an axis located on said spot image of said reference plate on said spot image-forming plane.

3. An alignment verification system as defined in claim 1, wherein said line sensor is constituted by a flat areal sensor and a slit plate turnably placed on said areal sensor for switching the direction of a slit through 90°

between said X- and Y-axis positions.

4. An alignment verification system as defined in claim 1, wherein said line sensor is constituted by a flat areal sensor and a couple of slit plates containing slits in the directions of said X- and Y-axis, respectively, said slit plates being selectively placed on said areal sensor for switching the sensor position between said X- and Y-axis positions.

5. An alignment verification system as defined in claim 1, wherein said bi-axial adjustment means includes a couple of adjuster screws threaded into diagonally opposing corner portions of said support table for tilting same about said X- and Y-axes.

6. An alignment verification system as defined in claim 2, wherein said rotational shaft is connected to a drive motor through a cam and cam follower switch mechanism.