Abstract: The invention relates to a viewing device, having a housing (2; 26) which has a front wall (3; 3?; 21; 29) with at least one viewing opening (8; 8?; 23; 28) for an object on view (10; 16; 24) that can be disposed or displayed inside the housing (2; 26) on the inner face (9; 91; 34; 51) of the back wall (4; 4?; 22; 32, 33), and to a blank (25) for producing such a viewing device. In order for the two-dimensional object on views (10; 16; 24) displayed in such a viewing device (1; 1?; 20; 27) to give a three-dimensional impression, the invention proposes embodying the outer face (100) of the front wall (3; 3?; 21; 29) of the housing (2; 26) of the viewing device (1; 1?; 20; 27) as curved toward the observer (7). The three-dimensional impression of the object on view (10; 16; 24) to be displayed can be still further enhanced if in addition the back wall (4; 4?; 22; 32, 33) of the housing (2; 26) of the viewing device (1; 1?; 20; 27) has an inner face (9; 9?; 34; 51) that is curved away from the observer (7).

Abstract: A power source device for diagnostic instruments is adapted for a connection of different types of illuminating devices and includes an active control unit for controlling an operating state of a power source in dependence on a type of a connected one of the illuminating devices.

Abstract: An illuminating apparatus for handheld or headworn instruments comprises a luminous means (50), a heat sink (42) for dissipating heat produced by the luminous means (50), and a ventilation device (57), fitted on the heat sink (42), for feeding cooling air to the heat sink (42). A damping device (60) for damping the oscillations generated by the ventilation device (57) is provided between the heat sink (42) and the ventilation device (57).

Abstract: A headband apparatus for head-worn optical instruments includes a headband (12) and a bow (16) on which the optical instrument is fitted, and which is fitted with both its ends (100) to the middle region of the headband (12) such that it can swivel about a swivel axis (S) between a working position and a rest position. Fastening elements (26, 28) for releasably fastening additional elements (38) are fitted on the headband (12).

Abstract: An ophthalmoscope includes a housing (12) in which there are arranged an observing unit and a light source between which there are/is arranged a diaphragm and/or a filter device that can be set via a swivel lever device (16, 17) mounted outside on the housing (12). The swivel lever device (16, 17) can be locked in respective latch stages by a locking device (41).