Scale member, method of producing the same and displacement measuring apparatus therewith

• US 6,668,467 B2
• Filed: 07/19/2001
• Issued: 12/30/2003
• Est. Priority Date: 07/19/2000
• Status: Expired due to Fees

• Current Assignee: Mitutoyo Corporation
• Original Assignee: Mitutoyo Corporation
• Inventors: Tominaga, Atsushi, Shimomura, Toshitaka
• Primary Examiner(s): Gutierrez, Diego
• Assistant Examiner(s): Smith, R. Alexander
• Application Number:
  US09/907,771
• Publication Number:
  US 20020014893A1
• Time in Patent Office: 894 Days
• Field of Search: 335/42, 337/06, 337/07, 337/08, 335/58, 335/61, 438/52, 438/53, 295/921, 295/95, 298/25, 324/622, 324/644, 324/699, 324/716, 324/207.11, 324/207.12, 324/207.13, 324/207.14, 324/207.15
• US Class Current: 33/542
• CPC Class Codes: G01D 5/347 using displacement encoding scales
• CPC Class Codes: G01D 5/34715 Scale reading or illumination devices
• CPC Class Codes: Y10T 29/49002 Electrical device making
• CPC Class Codes: Y10T 29/49007 Indicating transducer

Abstract

There is provided a displacement measuring apparatus efficiently productive and easily applicable to high precise measurement of displacement with contact probe detection for hardly-measurable works in the art such as micro-works and deep parts in complicated structures. A scale member includes a spindle and a scale both supported by a parallel leaf spring movable on a scale substrate. The spindle is arranged in coaxial with a measurement axis in the scale member. The L & S slit-processed scale is integrated with the spindle and supported by the parallel leaf spring to move together with the spindle along the measurement axis. The spindle, scale and parallel leaf spring are coupled to the scale substrate interposing an anchor of the parallel leaf spring therebetween. The spindle, scale and parallel leaf spring are formed in an integral structure and only the anchor contacts the scale substrate while the spindle, scale and parallel leaf spring slightly float from the scale substrate. A displacement sensor comprises a sensor substrate arranged opposite to the scale substrate. A light source and a photosensitive device are located on the sensor substrate.

Claims

1. A scale member, comprising:

a scale substrate;

a spindle arranged coaxially alone a measurement axis for receiving a displacement input along said measurement axis;

a scale displacing along said measurement axis, wherein the scale moves together with the spindle; and

a resilient support for supporting said spindle and scale on said scale substrate, the resilient support movable along said measurement axis, wherein said spindle, scale, resilient support and scale substrate are formed integrally through photolithography and etching processes applied to a laminated substrate of Si—

SiO₂—

Si.

2. The scale member according to claim 1, wherein said resilient support comprises a parallel leaf spring that has an anchor, the parallel leaf spring being coupled to said scale substrate through the anchor for supporting said spindle and scale in a state floating from said scale substrate.

3. The scale member according to claim 1, wherein said scale substrate has a groove formed in a proximity of said spindle.

4. The scale member according to claims 1, wherein said scale substrate has a notch formed in a proximity of said spindle.

5. A displacement measuring apparatus, comprising:

a scale member including

a scale substrate,

a spindle arranged coaxially along a measurement axis for receiving a displacement input along said measurement axis,

a scale displacing along said measurement axis, wherein the scale moves together with said spindle, and

a resilient support for supporting said spindle and scale on said scale substrate, the resilient support movable along said measurement axis, wherein said spindle, scale, resilient support and scale substrate are formed integrally using fine patterning technologies; and

a sensor for detecting a displacement of said scale of said scale member along said measurement axis,

wherein said sensor includes a sensor substrate, and a detecting device mounted on said sensor substrate for detecting a displacement of said scale, and wherein said scale member has a spacer and couples to said sensor substrate through the spacer so that said scale oppositely spaces a certain gap from said detecting device,

wherein said space is formed integrally with said scale member, said spacer and said sensor substrate having an anodic bonding therebetween.

6. The displacement measuring apparatus according to claim 5, wherein said sensor comprises an optical sensor including a light source for providing a light illuminating said scale and a photosensitive device for optically receiving a light from said scale, the optical sensor being configured to form an optical encoder together with said scale member.

7. The displacement measuring apparatus according to claim 5, wherein said sensor comprises an electrostatic capacitance sensor configured to form an electrostatic capacitance encoder together with said scale member.

8. The displacement measuring apparatus according to claim 5, wherein said sensor comprises an induced current sensor configured to form an induced current encoder together with said scale member.

9. The displacement measuring apparatus according to claim 5, wherein said sensor comprises a magnetic sensor configured to form a magnetic encoder together with said scale member.

10. A method of producing a scale member, said member including:

a scale substrate,

a spindle arranged coaxially along a measurement axis for receiving a displacement input along said measurement axis,

a scale displacing along said measurement axis, wherein the scale moves together with said spindle, and

a resilient support for supporting said spindle and scale on said scale substrate, the resilient support movable along said measurement axis, wherein said spindle, scale, resilient support and scale substrate are formed integrally using fine patterning technologies,

said method comprising;

providing a laminated substrate including a first semiconductor substrate, a sacrifice layer and a second semiconductor substrate laminated in this order;

performing a photolithography and anisotropic etching to said second semiconductor substrate to form portions to be said spindle, scale and resilient support linked together and a part of said resilient support extended wider that others; and

performing an isotropic etching to said sacrifice layer to remove a part of said sacrifice layer that is beneath said spindle, scale and resilient support while keeping another part of said sacrifice layer that is beneath said wider extended part of said resilient support.

11. The method of producing the scale member according to claim 10, further comprising the step of forming a spacer from a part of said second semiconductor substrate through a photolithography and anisotropic etching.