High sensitivity deflection sensing device
AssigneeThe Regents of the University of California
InventorsTILMAN E. SCHAFFER, PAUL K. HANSMA
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Abstract
A high sensitivity beam deflection sensing optical device, such as an atomic force microscope, including one or more of the following: specified means in the path of the incident beam for adjusting the size and/or power of the incident beam spot, means for moving the incident beam spot with movement of the object whereby to maintain the position of the spot on the object, and means for increasing the signal to noise ratio of the optical detector in which adjusted gains are applied to different segments of the optical detector.
Claims29
In a beam deflection sensing optical device, having a light source providing an incident beam, a lens for focusing the incident beam to a spot on an object and an optical detector for receiving the beam when reflected from the object the improvement whereby the sensitivity of the optical device is increased, comprising providing:
- (a) control means in the path of the incident beam for adjusting the size of the incident beam spot and including one or more objects placeable in the path of the incident beam and a plurality of movable, or interchangeable lenses, whereby to produce different size focused spots for respective selected objects;
- and/or
- (b) control means in the path of the incident beam for adjusting the power of the incident beam spot including a mask inserted in the path of the incident beam having adjacent regions through which the beam is transmitted, said adjacent regions having either different optical transmission characteristics or different shapes;
- and/or
- (c) means for viewing the spot and the object, and spot position control means based on imaging the object and the spot through the viewing means for moving the incident beam spot with movement of the object whereby to maintain the position of the spot on the object;
- and/or
- (d) control means for increasing the control signal to noise ratio of the optical detector, in which the optical detector has an array of three or more segments generating signals with gains adjusted based on evaluation of one or more segment signals, and means for adding the signals from said three or more segments to detect a change of position or shape of the spot as the reflected beam traverses said three or more segments.
In a beam deflection sensing optical device having a light source providing an incident beam, a lens for focusing the incident beam to a spot on an object, and an optical detector for receiving the beam when reflected from the object, the improvement whereby the sensitivity of the optical device is increased, comprising providing:
- (a) control means in the path of the incident beam for adjusting the size and power of the incident beam spot;
- and including one or more objects placeable in the path of the incident beam and a plurality of movable, or interchangeable lenses, whereby to produce different size focused spots for respective selected objects;
- and/or
- (b) means for viewing the spot and the objects and spot position control means based on imaging the object and the spot through the viewing means for moving the incident beam spot with movement of the object whereby to maintain the position of the spot on the object;
- and
- (c) control means for increasing the control signal to noise ratio of the optical detector, in which the optical detector has an array of three or more segments generating signals with gains adjusted based on evaluation of one or more segment signals, and means for adding the signals from said three or more segments to detect a change os position or shape of the spot as the reflected beam traverses said three or more segments.
A method for improving the sensitivity of a beam deflection sensing optical device having a light source providing an incident beam, a lens for focusing the incident beam to a spot on an object, and an optical detector having an array of three or more segments for receiving the beam when reflected from the object, comprising:
- (a) modifying the incident beam to adjust the size of the incident beam spot, said optical device including one or more objects placeable in the path of the incident beam, comprising the step of discretely adjusting the size of the incident beam spot whereby to produce different size focused spots for respective selected objects;
- and/or
- (b) adjusting the power of the incident beam spot by inserting a mask in the path of the incident beam said mask having adjacent regions through which the beam is transmitted, said adjacent regions having either different optical transmission characteristics or different shapes;
- and or
- (c) moving the incident beam spot with movement of the object whereby to maintain the position of the spot on the object;
- and/or
- (d) adjusting the gains of different segments of the optical detector based on an evaluation of one or more segment signals and adding the signals from said three or more segments to detect a change of position or shape of the spot as the reflected beam traverses said three or more segments whereby to increase the signal to noise ratio of the optical detector.
A method for improving the sensitivity of a beam detection sensing optical device having a light source providing an incident beam, a lens for focusing the incident beam to a spot on an object, and an optical detector having an array of segments for receiving the beam when reflected from the object, comprising:
- (a) modifying the incident beam to adjust the size of the incident beam spot, said optical device including one or more objects placeable in the path of the incident beam, comprising the step of discretely adjusting the size of the incident beam spot whereby to produce different size focused spots for respective selected objects;
- (b) adjusting the power of the incident beam spot by inserting a mask in the path of the incident beam, said mask having adjacent regions through which the beam is transmitted, said adjacent regions having either different optical transmission characteristics or different shapes.
- (c) moving the incident beam spot with movement of the object whereby to maintain the position of the spot on the object;
- and
- (d) adjusting the gains of different segments of the optical detector based on an evaluation of one or more segment signals and adding the signals from said one or more segments to detect a change of position or shape of the spot as the reflected beam traverses said three or more segments, whereby to increase the signal to noise ratio of the optical detector.
Dependencies are inferred from the claim text.