Speckle reduction device and compact, portable phoropter module
Publication Date: 2014-Apr-30
The IP.com Prior Art Database
The present technical disclosure describes an optical device for reducing speckle noise of laser light and a compact portable phoropter module. The laser speckle reduction device is based on a reluctance force based actuator which moves an optical element such as a diffusor. By combining various adaptive optics building blocks, compact portable ophthalmic instruments can be built. The combination of an electrically tunable lens with two rotating cylinder lenses enables compact phoropters and allows correcting spherical error and astigmatism. Optionally a tunable prism can be added.
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Speckle reduction device and Compact, portable phoropter module
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Speckle reduction device
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The present invention relates to an optical device for reducing Speckle noise according to claim 1.
Such an optical device for reducing Speckle noise of laser light comprises at least first optical element that acts as a diffusor, i.e., scatters light, and that extends along
10 an extension plane as well as an actuator means designed for oscillating said first optical element along said extension plane.
An optical device of the afore-mentioned kind is often used with laser light in order to suppress Speckle noise, which is an interference pattern that is created on the screen (objective speckles) or the retina of the human eye (subjective speckles) due
15 to the high coherency of the laser light.
Such a reduction can be accomplished by letting the light or laser beam pass through or reflect on a moving/oscillating diffuser. In case the frequency is high enough, the human brain integrates the perceived light over time which reduces the perceived speckle noise significantly. Such an optical device is for instance disclosed in US
20 2011/0043768 which describes a magnet-coil based moving diffuser with complex springs as well as in WO2010078662 which relates to a movable diffuser based on an actuation by means of electroactive polymers
Based on this, the problem underlying the present invention is to provide for an optical device adapted for the reduction of Speckle noise that is reliable, reduces
25 costs and special requirements while increasing thermal and mechanical stability at the same time.
This problem is solved by an optical device having the features of claim 1.
According thereto, said actuator means is formed as a reluctance actuator means that is designed to exert a reluctance force on the first optical element, so as to move
30 or stretch the first optical element along said extension plane.
Optical Device for Reducing Speckle Noise
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In the context of the present invention, said optical element is preferably designed to act as a diffusor, i.e., spread out or to scatter light in some manner, wherein particularly said optical element can be one of the following elements:
A diffuser, a volume diffuser, a surface diffuser, a diffractive diffuser, a microlense, a
5 line diffuser, a square diffuser, a cylinder lens array, a fly-eye, or a deformable polymer.
Further, in the present invention, the (e.g. first) optical element can be made of a glass, a polymer, an elastomer, a plastic or any other transparent or reflecting material. It can be a surface or an engineered volume etc. (see also above).
10 Further, a stretching of the optical element for Speckle reduction may be performed in case said first optical element is made out of deformable material such as polymer, wherein the optical properties of the optical element may be altered by stretching it.