Liquid crystal camera aperture
A camera captures visual images from light passed through a lens aligned with an image sensor and interfaced with an image signal processor. A non-mechanical aperture coupled at the lens adjusts the camera aperture with plural areas selectively blocked from passing light by application of an electric field to a liquid crystal layer. Orthogonal polarizers on the front and rear sides of the liquid crystal layer block passage of light when an electric field is absent and selectively pass light with incremented decrease of the camera aperture as areas of concentric circles from a center out to a perimeter once an electric field is applied.
1 . An information handling system comprising:
a housing;
a processor coupled in the housing and operable to execute instructions to process information;
a memory coupled in the housing and operable to store the instructions and information;
a wireless network interface controller operable to communicate the information through a network;
a persistent storage operable to store the instructions and information;
a camera interfaced with the processor and operable to capture visual images for communication through the network, the camera having an image signal processor, an image sensor and a lens, the lens aligned to direct light at the image sensor, the image signal processor capture a visual image from the light detected by the image sensor;
an aperture interfaced with the image signal processor and aligned with the lens, the aperture having a liquid crystal layer with plural areas, each of the plural areas associated with an F-number of the lens, the aperture having a first polarizer coupled in front of the lens, a second polarizer coupled at a rear of the lens and the liquid crystal layer between the first polarizer and the second polarizer; and
a non-transient memory storing instructions that when executed on the image signal processor selectively apply an electric field to each of the plural areas to have a predetermined F-number.
2 . The information handling system of claim 1 further comprising:
plural concentric circles of indium tin oxide wire in the liquid crystal layer, each circle defining one of the plural areas; and
instructions that when executed on the image signal processor incrementally apply the electrical field from the inner most concentric circle to the outer most concentric circle as the predetermined F-number decreases.
3 . The information handling system of claim 2 wherein a neutral state of the liquid crystal layer without any charge applied blocks light from passing through the lens.
4 . The information handling system of claim 2 wherein the liquid crystal layer couples at the rear side of the lens.
5 . The information handling system of claim 4 wherein the first and second polarizers have the same orientations and the liquid crystal layer rotates light polarization when an electric field is applied to block light passage to the lens.
6 . The information handling system of claim 4 wherein the first and second polarizers have orthogonal orientations and the liquid crystal layer rotates light polarization when an electric field is applied to unblock light passage to the lens.
7 . The information handling system of claim 6 further comprising plural pads defined in the liquid crystal layer, each pad interfaced with a one of the concentric circles to selectively apply the electric field.
8 . The information handling system of claim 2 wherein the camera integrates into the housing.
9 . The information handling system of claim 2 wherein the camera couples into a camera housing separate from the housing.
10 . A method for capturing visual images comprising:
aligning a lens to focus light on an image sensor;
coupling a first polarizer at a front side of the lens;
coupling a second polarizer at a rear side of the lens;
coupling a liquid crystal between the first polarizer and the second polarizer; and
adjusting charge at the liquid crystal layer to adjust the polarization of light passed through the first polarizer to selectively block and pass light through the second polarizer;
selectively applying charge to an aperture liquid crystal layer to pass light through the lens with a selected F-number; and
capturing a visual image with an image signal processor coupled to the image sensor.
11 . The method of claim 10 further comprising:
separating the liquid crystal into plural areas of concentric circles with indium tin oxide wire; and
selectively applying charge to unblock the plural areas of concentric circles from an inner area to an outer area to decrease the F-number.
12 . The method of claim 11 further comprising:
coupling the liquid crystal at the rear side of the lens.
13 . The method of claim 12 wherein the first and second polarizers have the same orientations and the liquid crystal layer rotates light polarization when an electric field is applied to block light passage to the lens.
14 . The method of claim 12 wherein the first and second polarizers have orthogonal orientations and the liquid crystal layer rotates light polarization when an electric field is applied to unblock light passage to the lens.
15 . The method of claim 12 further comprising:
defining plural pads in the liquid crystal layer, each pad interfaced with a concentric circle; and
interfacing each pad with an image signal processor to control the F-number by applying current to the pads.
16 . A camera comprising:
an image signal processor;
an image sensor;
a lens aligned to direct light at the image sensor, the image signal processor capturing a visual image from the light detected by the image sensor;
an aperture interfaced with the image signal processor and aligned with the lens, the aperture having a first polarizer at a front side of the lens, a second polarizer at a rear side of the lens and a liquid crystal layer with plural areas between the first polarizer and the second polarizer, each of the plural areas associated with an F-number of the lens; and
a non-transient memory storing instructions that when executed on the image signal processor selectively apply an electric field to each of the plural areas to have a predetermined F-number.
17 . The camera of claim 16 further comprising:
plural concentric circles of indium tin oxide wire in the liquid crystal layer, each circle defining one of the plural areas; and
instructions that when executed on the image signal processor incrementally apply the electrical field from the inner most concentric circle to the outer most concentric circle as the predetermined F-number decreases.
18 . The camera of claim 17 wherein the liquid crystal layer couples at the rear side of the lens.
19 . The camera of claim 18 wherein the first and second polarizers have orthogonal orientations and the liquid crystal layer rotates light polarization when an electric field is applied to unblock light passage to the lens.
20 . The camera of claim 19 further comprising plural pads defined in the liquid crystal layer, each pad interfaced with a one of the concentric circles to selectively apply the electric field.