AUTOFOCUS LENS SYSTEM FOR INDICIA READERS
First Claim
1. An autofocus lens system for an imaging scanner, comprising:
- a first lens fixedly positioned along an optical axis;
a second lens fixedly positioned along the optical axis; and
a focusing-module lens fixedly positioned along the optical axis between the first lens and the second lens, the focusing-module lens formed from two adjustable surfaces, wherein the optical power of the adjustable surfaces is controlled electronically to achieve focus, and wherein the focusing-module lens comprises (i) a first transparent deformable membrane having a ring-shaped piezoelectric film contiguously positioned on the first transparent deformable membrane'"'"'s outer surface, (ii) a second transparent deformable membrane having a ring-shaped piezoelectric film contiguously positioned on the second transparent deformable membrane'"'"'s outer surface, and (iii) a flexible polymer contiguously positioned between the first transparent deformable membrane and the second transparent deformable membrane, whereby the flexible polymer is in contact with the respective inner surfaces of the first transparent deformable membrane and the second transparent deformable membrane.
1 Assignment
0 Petitions
Accused Products
Abstract
An autofocus lens system includes no conventional moving parts and has excellent speed and low power consumption. The system includes a small electronically-controlled focusing-module lens. The focusing-module lens includes two adjustable polymeric surfaces (e.g., two adjustable-surface lenses in a back-to-back configuration). The curvature of the surfaces can be adjusted to change focus. The performance of the autofocus lens system is extended by adding a conventional first and second lens, or lens group, on either side of the focusing-module lens. What results is an autofocus lens system with excellent near field and far field performance.
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Citations
24 Claims
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1. An autofocus lens system for an imaging scanner, comprising:
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a first lens fixedly positioned along an optical axis; a second lens fixedly positioned along the optical axis; and a focusing-module lens fixedly positioned along the optical axis between the first lens and the second lens, the focusing-module lens formed from two adjustable surfaces, wherein the optical power of the adjustable surfaces is controlled electronically to achieve focus, and wherein the focusing-module lens comprises (i) a first transparent deformable membrane having a ring-shaped piezoelectric film contiguously positioned on the first transparent deformable membrane'"'"'s outer surface, (ii) a second transparent deformable membrane having a ring-shaped piezoelectric film contiguously positioned on the second transparent deformable membrane'"'"'s outer surface, and (iii) a flexible polymer contiguously positioned between the first transparent deformable membrane and the second transparent deformable membrane, whereby the flexible polymer is in contact with the respective inner surfaces of the first transparent deformable membrane and the second transparent deformable membrane. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 10, 12, 13, 14, 15)
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9. (canceled)
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11. (canceled)
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16. An autofocus lens system for an imaging scanner, comprising:
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a first positive lens group including a plurality of lenses fixedly positioned along an optical axis; a second positive lens group including a plurality of lenses fixedly positioned along the optical axis; a focusing-module lens fixedly positioned along the optical axis between the first positive lens group and the second positive lens group and formed from two adjustable surfaces whose optical power is electronically controlled to achieve focus, wherein the focusing-module lens (i) defines an aperture stop for the autofocus lens system and (ii) has a clear aperture whose diameter is smaller than the diameter of either the first lens group or the second lens group. - View Dependent Claims (17, 18, 19)
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20. An active autofocus system for an imaging scanner, comprising:
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an autofocus lens system, comprising (i) a first positive lens fixedly positioned along an optical axis, (ii) a second positive lens fixedly positioned along the optical axis, and (iii) a focusing-module lens fixedly positioned along the optical axis between the first positive lens and the second positive lens and formed from two adjustable surfaces, wherein the optical power of the adjustable surfaces is controlled electronically to achieve focus of a real image of a barcode; a range finder for sensing the range of a barcode through transmitted and received radiation and for creating a range signal representing the sensed range; a lookup table stored in memory, the lookup table containing focus settings associated with range-signal values; a processor for running a process that compares the range signal with the lookup table in order to generate a corresponding control signal; and a controller for reading the control signal and for outputting electronic autofocus signals to adjust the autofocus lens system. - View Dependent Claims (21, 22, 23, 24)
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Specification