Camera module with tolerance adjustment using embedded active optics

a technology of optical control and camera module, which is applied in the field of optical devices and assemblies, can solve the problems of insufficient optical and physical manufacturing tolerances to ensure the desired precision, and the overall device focusing power is changed, so as to achieve acceptable optical performance and shorten the overall lens design. the effect of the improvemen

US20120200764A1Inactive Publication Date: 2012-08-09POINT FINANCIAL
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Patent Information

Authority / Receiving Office
US · United States
Patent Type
Applications(United States)
Current Assignee / Owner
Publication Date
2012-08-09
Estimated Expiration
Not applicable · inactive patent

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Abstract

A focus free camera module uses fixed lenses within a housing that are combined with an electrically controllable active optical element, such as a tunable liquid crystal lens. The fixed lenses provide a desired amount of optical power, but the manufacturing tolerances of the module are insufficient to ensure a proper focus of an image on an image sensor. The active optical element is therefore used to compensate for any variations in the optical power to achieve the desired focus. To ensure an effective compensation, the module may be constructed so that, when the variation in optical power due to manufacturing tolerances is at a maximum, the desired focus is achieved when the active optical element is at zero optical power. All other variations may then be compensated by adjusting the active optical element to increase its optical power.
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Description

[0001] This application claims priority of U.S. provisional patent application 61 / 175,025 filed May 3, 2009.FIELD OF THE INVENTION

[0002] This invention relates generally to optical devices and assemblies and, more specifically, to lenses having active optical control.BACKGROUND OF THE INVENTION

[0003] Lens structures for optical devices such as cameras consist of multiple lens elements assembled in a single barrel or stacked in a wafer form, utilizing spacers, to create fixed focus lens assemblies. These lens structures have a fixed focal plane and are mechanically moved to focus on objects in varying distances to the camera system.

[0004] Tunable liquid crystal lenses (TLCL) that have a flat layer construction are known in the art, as described in PCT patent application WO 2007 / 098602, published on Sep. 7, 2007, as well as in PCT patent application publication WO 2009 / 153764 published Dec. 23, 2009, the specifications of which are hereby incorporated by reference as if fully set forth he...

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Embodiment Construction

[0035]The present invention is directed to an optical lens apparatus that uses fixed lenses in combination with an electrically controllable liquid crystal optical device. Depending on the specific configuration, the apparatus may be directed to one of several applications. In each of these embodiments, the apparatus uses the optical properties of the fixed lenses in combination with the electrically controlled optical properties of the liquid crystal device.

[0036]Shown in FIG. 1 is a schematic view of a first embodiment of the invention in which a variable focus lens 10 has a barrel structure consisting of two portions, an outer portion 12 and an inner portion 14. The lens may be used in a variety of different applications, including compact digital cameras, such as might be integrated into a portable telephone. Each of the two portions includes a fixed lens, lens 16 in the outer portion 12, and lens 18 in the inner portion 14. Each of the lenses in this embodiment are an integral ...