Sensor for rotational velocity and rotational acceleration
Filing Information
- Patent Number: US5796098
- Application Number: US8717548
- Filing date: 09/20/1996
- Issue date: 08/18/1998
- Predicted expiration date: 09/20/2016
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analyzing 100 million+ documents to uncover your network...- U.S. Classifications: 250/231.13 · 250/225 ·
- International Classifications: G01D 534 ·
- International Classifications: 250231.13;231.18;231.17;231.14;225;214.1 ·
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Abstract
Novel rotation sensors are disclosed, sensors with a temporal resolution of one measurement per rotation. A transparent or absorbing substrate can be coated with a transparent thin film to produce a linear response in reflectance versus angle of incidence over a certain range of angles. The best results were obtained when the incident light was s-polarized. For example, a Si substrate coated with an SiO.sub.2 film was used in constructing a reflection rotation sensor. Experimental results and an error analysis of this rotation sensor are presented.References Cited
U.S. Patent Documents
| Document Number | Assignees | Inventors | Issue/Pub Date |
|---|---|---|---|
| US5059901 | Technology for Energy Corporation | Van Voorhis | Oct 1991 |
Other Publications
| R.M.A. Azzam, "Lima.cedilla.on of Pascal locus of the complex refractive indices of interfaces with maximally flat reflectance-versus-angle curves for incident unpolarized light," J. Opt. Soc. Am. A, vol. 9, pp. 957-963, Jan. 1992. |
| R.M.A. Azzam et al., "Single-layer-coated surfaces with linearized reflectance versus angle of incidence: application to passive and active silicon rotation sensors," J. Opt. Soc. Am. A, vol. 12, pp. 1790-1796, Mar. 1995. |
| R.M.A. Azzam, "Stationary property of normal-incidence reflection from isotropic surfaces," J. Opt. Soc. Am., vol. 72, pp. 1187-1189, Sep. 1982. |
| H.B. Holl, "Specular Reflection and Characteristics of Reflected Light," J. Opt. Soc. Am., vol. 57, pp. 683-690, Jan. 1967. |
| R.M.A. Azzam, "Angle-of-incidence derivatives of the complex parallel and perpendicular reflection coefficients and their ratio for a film-substrate system," Optica Acta, vol. 30, pp. 1113-1124, Jan. 1983. |
Referenced By
| Document Number | Assignee | Inventors | Issue/Pub Date |
|---|---|---|---|
| US7557906 | Sick AG | Stefan Mack | Jul 2009 |
Patent Family
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Independent Claims | See all claims (21)
- 1. A sensor for measuring rotational velocity, comprising:(a) a specularly reflective coated surface;(b) a source of monochromatic light positionable so that the light reflects from said coated surface;(c) means for measuring, as a function of time, the intensity of light reflected from said coated surface over a range of incident angles; and(d) means for calculating the rotational velocity of said coated surface as being proportional to the time rate of change of the measured intensity of reflected light within the range of incident angles thereby measured.
- 4. A sensor for measuring torsional velocity, said se comprising:(a) a photodiode having a specularly reflective coated surface, wherein an electric potential is induced in said photodiode by light incident on the coated surface;(b) a source of light positionable so that the light reflects from said coated surface;(c) means for measuring, as a function of time, the electric potential induced in said photodiode by the incident light at a range of incident angles; and(d) means for calculating the rotational velocity of said coated surface as being proportional to the time rate of change of the measured electric potential within the range of incident angles thereby measured.
- 7. A coated surface that will reflect incident light; said coated surface comprising a substrate and a film coating said substrate; wherein the refractive index of the substrate, the refractive index of the film, and the thickness of the film are such that the second derivative and the third derivative of the reflectance of said coated surface, with respect to the angle of light incidence .phi. measured versus a direction normal to said coated substrate, are both zero at a particular angle of incidence .phi.=.phi..sub.0 greater than 30.degree. for a particular wavelength .lambda. of incident unpolarized, s-polarized, or p-polarized light; whereby the intensity reflectance of incident unpolarized, s-polarized, or p,-polarized light at wavelength .lambda. is, to within .+-.1%, a linear function of angle of incidence .phi. over a range of angles .phi..sub.1 through .phi..sub.2 that includes .phi..sub.0, wherein the difference between .phi..sub.1 and .phi..sub.2 is at least 4.degree..
