1. A magnetic null accelerometer comprising:
first and second capacitor plates arranged in parallel spaced apart a given distance from each other;
a flexure plate mounted in between said first and second capacitor plates and capable of flexing in response to acceleration forces applied thereon, said flexure plate having a first side facing said first capacitor plate for forming a first capacitor generating a first capacitance signal based on its distance from said first capacitor plate, and having a second side facing said second capacitor plate for forming a second capacitor generating a second capacitance signal based on its distance from said second capacitor plate, and said flexure plate having a null position between said first and second capacitor plates at which the first and second capacitance signals are equal;
a capacitance measuring circuit for measuring the first and second capacitance signals and detecting a difference between them as an indicator of offset of said flexure plate from its null position to a flexed position under acceleration forces;
a magnet coupled to said flexure plate between said first and second capacitor plates, and a current-controlled coil having a single windings receiving a single control current for generating a magnetic force opposing the magnetic field of the magnet when said flexure plate is in a flexed position so as to restore said flexure plate to its null position; and
a compensation circuit for generating a single control current in response to the difference between the first and second capacitance signals measured by said capacitance measuring circuit and for applying the corresponding single control current to said coil so as to restore said flexure plate to its null position.
2. A magnetic null accelerometer according to claim 1, wherein said capacitance measuring circuit includes a first oscillator for generating a first frequency signal proportional to the first capacitance signal, a second oscillator for generating a second frequency signal proportional to the second capacitance signal, and a frequency subtractor for generating a frequency difference signal as an indicator of offset of said flexure plate to a flexed position under acceleration forces.
3. A magnetic null accelerometer according to claim 2, further comprising a digital-to-analog converter for converting the frequency difference signal generated by said capacitance measuring circuit into an analog voltage proportional to the offset of said flexure plate at the flexed position, and wherein said compensation circuit compensation circuit generates the corresponding single control current in response to the analog voltage to drive said coil so as to restore said flexure plate to its null position.
4. A magnetic null accelerometer according to claim 1, further comprising a current sensor which detects the single control current used to drive said coil and generates an output signal proportional to the force required to restore said flexure plate to its null position as an indicator of the acceleration forces applied to said flexure plate.
5. A magnetic null accelerometer control circuit comprising:
a first capacitor plate spaced apart a distance from a flexure plate which is capable of flexing in response to acceleration forces applied thereon, said flexure plate having a first side facing said first capacitor and forming a first capacitor for generating a first capacitance signal based on its distance from said first capacitor plate, and said flexure plate having a null position relative to said first capacitor plate;
a capacitance measuring circuit for measuring the first capacitance signal and detecting a difference indicator of offset of said flexure plate from its null position to a flexed position under acceleration forces;
a magnet coupled to said flexure plate, and a current-controlled coil having a single windings receiving a single control current for generating a magnetic force opposing the magnetic field of the magnet when said flexure plate is in a flexed position so as to restore said flexure plate to its null position; and
a compensation circuit for generating a single control current in response to the difference indicator measured by said capacitance measuring circuit and for applying a the corresponding single control current to said coil so as to restore said flexure plate to its null position.
6. A magnetic null accelerometer according to claim 5, further comprising a second capacitor plate spaced apart in parallel a given distance from said first capacitor plate with said flexure plate between them, said flexure plate having a second side facing said second capacitor plate for forming a second capacitor therewith generating a second capacitance signal based on its distance from said second capacitor plate, wherein said capacitance measuring circuit measures the first and second capacitance signals and detects a difference between them as an indicator of offset of said flexure plate from its null position to a flexed position under acceleration forces.
7. A magnetic null accelerometer according to claim 6, wherein said capacitance measuring circuit includes a first oscillator for generating a first frequency signal proportional to the first capacitance, a second oscillator for generating a second frequency signal proportional to the second capacitance, and a frequency subtractor for generating a frequency difference signal as an indicator of offset of said flexure plate from its null position to a flexed position under acceleration forces.
8. A magnetic null accelerometer according to claim 7, further comprising a digital-to-analog converter for converting the frequency difference signal generated by said capacitance measuring circuit into an analog voltage proportional to the offset of said flexure plate at the flexed position, and wherein said compensation circuit compensation circuit generates the single control current in response to the analog voltage to drive said coil so as to restore said flexure plate to its null position.
9. A magnetic null accelerometer according to claim 5, further comprising a current sensor which detects the single control current used to drive said coil and generates an output signal proportional to the force required to restore said flexure plate to its null position as an indicator of the acceleration forces applied to said flexure plate.
10. A method for operating a flexure plate accelerometer comprising:
providing a first capacitor plate spaced apart a distance from a flexure plate which is capable of flexing in response to acceleration forces applied thereon,
providing a first side of the flexure plate facing the first capacitor plate and forming a first capacitor therewith for generating a first capacitance signal based on its distance from the first capacitor plate, wherein the flexure plate has a null position relative to the first capacitor plate;
measuring the first capacitance signal and detecting a difference indicator of offset of the flexure plate from its null position to a flexed position under acceleration forces;
providing a magnet that is coupled to the flexure plate, and a current-controlled coil having a single windings receiving a single control current for generating a magnetic force opposing the magnetic field of the magnet when the flexure plate is in a flexed position so as to restore the flexure plate to its null position; and
generating a single control current in response to the difference indicator measured as an offset of the flexure plate from its null position to a flexed position under acceleration forces, and applying it to the coil to drive the magnet so as to restore the flexure plate to its null position.
11. A method for operating a flexure plate accelerometer according to claim 10, further comprising providing a second capacitor plate spaced apart in parallel a given distance from the first capacitor plate with the flexure plate between them, and providing the flexure plate with a second side facing the second capacitor plate and forming a second capacitor therewith for generating a second capacitance signal based on its distance from the second capacitor plate, and measuring the first and second capacitance signals to detect a difference between them as an indicator of offset of the flexure plate from its null position to a flexed position under acceleration forces.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An objective compound lens, applied to an optical scanner having at least a light source, a reflection compound mirror and an optical sensor, wherein the light source is used to radiate a document to obtain an image light, the reflection compound mirror is located in an optical path of the image light to project the image light on the optical sensor, and the objective compound lens is located between in the optical path of the image light between the optical sensor and the reflection compound mirror, the objective compound lens comprising:
a basic objective lens having a first linkage, ; and
a plurality of compound lenses having corresponding second linkage respectively, wherein any one of the second linkages is suitable for connecting and detaching with the basic objective lens via the first linkage;
wherein when the basic objective lens is coupled to a selected one of the selected plurality of compound lens lenses located on the optical path of the image light between the basic objective lens and the reflection compound mirror, the optical scanner has a resolution corresponding to the selected compound lens, and when any one of the compound lenses is not connected to the basic objective lens, the image light is projected on the optical sensor via the basic object objective lens only.
2. The object compound lens according to claim 1, wherein the first linkage comprises a screw thread, and wherein the second linkage also comprises a screw corresponding to the screw thread of the first linkage.
3. The optical objective compound lens according to claim 1, wherein the second linkage of the selected compound lens can be capped to the first linkage.
4. A scanner, comprising:
means for illuminating a document to provide image light representing the document;
means for reflecting the image light to direct the image light along a light path;
means for focusing the reflected image light on an optical sensor, wherein the focused image light corresponds to a first scanning resolution; and
means for releasably coupling a compound lens component to the focusing means, wherein the releasably coupling means is attached to the focusing means or the compound lens component;
wherein, if the compound lens component is coupled to the focusing means, the focused image light corresponds to second scanning resolution.
5. The scanner of claim 4, wherein the releasably coupling means comprises a screw thread.
6. The scanner of claim 4, wherein the first scanning resolution is 600 dpi.
7. The scanner of claim 6, wherein the second scanning resolution is 1200 dpi, 1600 dpi, or 2400 dpi.
8. The scanner of claim 4, wherein the focusing means is affixed to the scanner and the compound lens component is interchangeable with other compound lens components.
9. A scanner, comprising:
an optical module containing a light source, a reflection component and an optical sensor, wherein the light source is used to illuminate a document to obtain an image light, and wherein the reflection component is located in an optical path of the image light to direct the image light on the optical sensor; and
a basic objective lens component located on the optical path of the image light between the optical sensor and the reflection component, wherein the basic objective lens component includes a first linkage configured to removably attach to a corresponding second linkage of a compound lens component.
10. The scanner of claim 9, wherein the scanner is operable to scan the document at a first resolution.
11. The scanner of claim 10, wherein if the compound lens component is removably coupled to the basic objective lens component using the linkages, the optical scanner is operable to scan the document at a second resolution.
12. The scanner of claim 9, wherein one of the linkages comprises a screw and the other linkage comprises a screw thread.
13. The scanner of claim 9, wherein the first linkage is located on an outside of the basic objective lens component.