An optical adapter for connecting between a beam splitter of a surgical microscope or an ophthalmic slit lamp microscope and a digital camera equipment including mobile phones, tablet computers, cameras, video cameras with image capturing function is provided. The optical adapter includes a lens group located on an optical path and an optical image rotating lens group for adjusting a direction of an optical image on a photosensitive unit of the digital camera equipment. The optical image rotating lens group is configured to be either independently rotatable around optical axis or be set fixedly. Embodiments of the present invention provide a system and method for real-time adjustment of the direction of an optical image on the photosensitive unit of a digital camera equipment, where regardless of the position of the digital camera a satisfactory direction of the optical image can be obtained with a simple user friendly and convenient structure.

A deroll control system includes an outer housing, a detector configured to capture an image, an annular torsional flexure, at least one drive and a controller configured to control the at least one drive. The annular torsional flexure has a rotatable inner mount surface to which the detector is mounted, a fixed outer mount surface fixed to the outer housing and spaced radially apart from the rotatable inner mount surface, and a flexure region having a plurality of flexures spaced radially between the inner mount surface and the outer mount surface. The at least one drive is coupled to the inner mount surface of the torsional flexure and is configured to cause a counter-rotation of the inner mount surface and the detector about a central rotational axis perpendicular to an image plane to correct a rotation of the image as the detector is capturing the image.

A device (100) for compensating for part of the visual field comprises a wearable frame (110) configured to rest upon the face of a subject. An image capture device (120) is configured to capture an image from a first region (20) of the subject's visual field the first region being identified as a region of the visual field in which the subject's vision is impaired, and relay the image to an image display unit (130). The image display unit (130) is configured to project the image onto a region of the subject's retina that corresponds to a second region of the subject's visual field, in which the subject's vision is identified as non-impaired. Associated methods are also described.

An optical focus control and method use rotations of a set of shift-invariant optical elements (Risley elements) that are fairly tolerant to optical misalignments and wobble in control systems. The Risley elements can be Risley prisms, Risley gratings, or photonic crystals that impart a fixed angular offset. Aligning at least one pair of Risley elements that are individually rotated can achieve an angular correct to light received off-axis for better detection by an optical detector, improving focus control.

A lens apparatus includes an optical element, a fixed member, a movable member configured to hold the optical element and movable in an optical axis direction relative to the fixed member, a guide member configured to guide a movement of the movable member in an optical axis direction, a first support member and a second support member spaced from each other in the optical axis direction, a pair of rotating elements held by the first support member and the second support member, respectively, and a biasing member configured to bias the pair of rotating elements and the guide member into contact with each other. The first support member and the second support member are fixed to one of the movable member and the fixed member. The guide member is fixed to the other of the movable member and the fixed member.

A method for controlling an optical element driving mechanism, including controlling a driving assembly by a control assembly to drive a movable to move relative to a fixed portion. The movable portion is used for connecting to an optical element, and the movable portion is movable relative to the fixed portion.

A deroll control system includes an outer housing, a detector configured to capture an image, an annular torsional flexure, at least one drive and a controller configured to control the at least one drive. The annular torsional flexure has a rotatable inner mount surface to which the detector is mounted, a fixed outer mount surface fixed to the outer housing and spaced radially apart from the rotatable inner mount surface, and a flexure region having a plurality of flexures spaced radially between the inner mount surface and the outer mount surface. The at least one drive is coupled to the inner mount surface of the torsional flexure and is configured to cause a counter-rotation of the inner mount surface and the detector about a central rotational axis perpendicular to an image plane to correct a rotation of the image as the detector is capturing the image.

There is provided an image pickup unit which is capable of achieving a focused image of a favorable depth of field while changing a visual field direction of observation.

An image pickup unit, comprises a front group which includes a prism that can be rotated for changing a visual field direction, and a rear group which includes a lens group and an image pickup element, wherein the image pickup unit includes a prism rotating section which rotates the prism for changing the visual field direction, and a focusing section which does not change a focused range, as an angle of visual field direction with respect to a longitudinal direction of the image pickup unit becomes smaller than a specific angle, and which moves the focused range toward a near-point side, as an angle of visual field direction with respect to the longitudinal direction of the image pickup unit becomes larger than the specific angle, in accordance with a rotation of the prism, and the focusing section, in a case in which the specific angle is not smaller than 30°, moves the focused range toward the near-point side.

An optical system including a unity magnification, finite conjugate, all-reflective image relay configured to receive optical radiation representing an input image and to relay the optical radiation via five reflections to an output image plane to provide an output image at the output image plane, the output image being a unity magnification copy of the input image. In certain examples the optical system includes foreoptics configured to produce the input image. The foreoptics and the image relay can be telecentric.

An optical system for real-time closed-loop control of a fundus camera and an implementation method therefor. The optical system comprises an optical path structure composed of a fundus camera, light sources (LS1, LS2), a plurality of lenses (L1, L2, L2′, L3′) and a dividing mirror (DM1, DM2), and further comprises an orthogonal steering mirror group, which comprises: a first steering mirror (SM1) moving in a horizontal direction and a second steering mirror (SM2) moving in a vertical direction. The optical system converts fundus motion information obtained from a fundus camera image to residual motion information compensated by means of the first steering mirror (SM1) and the second steering mirror (SM2), uses a relationship between control parameters, and by means of a translation control instruction or/and the fundus rotation control instruction, operates the first steering mirror (SM1) and the second steering mirror (SM2) in real time to compensate for translational motion or/and controls the fundus camera to compensate for fundus rotation. By using the optical system and the implementation method therefor, and by improving the optical system of the fundus camera, the optical system is enabled to have a real-time closed-loop control function so as to implement real-time optical tracking of a fundus/retina position and a target.