Lens characterization apparatus and method
First Claim
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1. An apparatus to characterize a performance of an optical lens comprising:
- a beam of scanned light which scans across said lens;
a light sensor for receiving said beam after said beam passes through said lens, said sensor generating a signal which is proportional to an amount of said beam striking said sensor;
an encoder positioned between said lens and said sensor to encode said light passing through to said sensor, said beam travelling across a window having a transparent opening disposed on an opaque face of said encoder, said opening having a plurality of sawtooth shaped openings such that said amount of said beam penetrating through said opening to said sensor as said beam scans across said lens is made to vary due to said sawtooth shaped openings, said encoding provided by said beam transitioning between opaque and transparent regions of said face;
a means coupled to said sensor for determining a rate of change of said signal in respect to a scanning time of said beam travelling across said sawtooth shaped opening;
whereby distortion caused by said lens is determined.
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Abstract
A beam of light, such as a laser, is used to scan across a lens. The beam passing through the lens is modulated by an optical encoder which controls the amount of the beam passing through the encoder to a light receptor. The received light is quantified and processed to determine any distortion caused by the lens. The encoder is comprised of a set of transparent windows upon an opaque face, the windows having a certain pattern that a beam travelling across the windows casts a specific light intensity pattern. The encoder also allows determination of astigmatism of the lens and distortion inherent in the beam itself.
17 Citations
24 Claims
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1. An apparatus to characterize a performance of an optical lens comprising:
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a beam of scanned light which scans across said lens; a light sensor for receiving said beam after said beam passes through said lens, said sensor generating a signal which is proportional to an amount of said beam striking said sensor; an encoder positioned between said lens and said sensor to encode said light passing through to said sensor, said beam travelling across a window having a transparent opening disposed on an opaque face of said encoder, said opening having a plurality of sawtooth shaped openings such that said amount of said beam penetrating through said opening to said sensor as said beam scans across said lens is made to vary due to said sawtooth shaped openings, said encoding provided by said beam transitioning between opaque and transparent regions of said face; a means coupled to said sensor for determining a rate of change of said signal in respect to a scanning time of said beam travelling across said sawtooth shaped opening; whereby distortion caused by said lens is determined. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An apparatus for characterizing the performance of an optical lens comprising:
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a beam of scanning light which scans across said lens; a light sensor for receiving said beam after said beam passes through said lens, said sensor generating a signal which is proportional to an intensity of said beam striking said sensor; an encoder positioned between said lens and said sensor to modulate an amount of said light passing through to said sensor, (a) a face of said encoder being perpendicular to said beam; (b) said face being opaque and preventing penetration of said beam; (c) said face including a window having sawtooth shaped openings therein, wherein said openings permit encoding of said beam by controlling said light penetrating to said sensor; (d) said scanning causing said beam to travel across said window, such that more of said beam penetrates through to said sensor as said beam scans across each tooth of said sawtooth opening; a processor coupled to said light sensor to determine a rate of change of said signal in respect to time, such that said rate of change at a trailing edge of each of said sawtooth opening having a Gaussian distribution of uniformly spaced peaks if no distortion is present; whereby said distortion caused by said lens is determined. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16)
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17. A method to characterize a performance of an optical lens, said method comprising the steps of:
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scanning a beam of light across a face of said lens; encoding said beam of light after passing through said lens, said encoding provided by a transparent window having a plurality of sawtoothed shaped openings upon an opaque face, wherein said scanning causes said beam to travel across said window such that an amount of said beam penetrating through said window as said beam scans across said lens is dependent on said sawtoothed shaped openings; receiving of said beam passing through said window by using a light sensor, wherein said light sensor generates a signal proportional to an amount of encoded light received; quantifying said signal to determine a rate of change of said signal in respect to a scanning time of said beam travelling across said sawtooth shaped openings such that said quantified result is compared to an expected undistorted result; whereby a distortion caused by said lens is determined. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
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Specification