Magnifying glass with illumination means for use in medicine and an illumination means

[0001] The invention relates to a magnifying glass as claimed in the preamble of claim 1 and to an illumination means as claimed in the preamble of claim 10.

[0002] Especially in medicine, for example in microsurgery, but also in other areas of medicine, magnifying glasses are known, for example as telescopic spectacles or as magnifying glasses mounted on a headband. Furthermore, illumination means are also known for these magnifying glasses, with which (illumination means) the respective viewing field or surgical field can be illuminated.

[0003] Light sources for these illumination means have recently been halogen lamps with the pertinent optics. The major disadvantages are that these illumination means have high heat evolution and relatively large dimensions and require high electric power for their operation so that either only stationary power supply devices with the defect of no mobility or battery-operated power supply units which can be carried on the body and which are heavy can be used.

[0004] In particular, a binocular magnifying glass which can be worn with a headband with two magnifying optics and one illumination means (WO 96/25873) is known. The latter consists essentially of a light source which is spatially separate from the magnifying glass and the illumination means there, the light from which source is coupled into the illumination means via an optical fiber. This known version among others has the defect that the optical fiber is disruptive when a binocular magnifying glass is being used and the freedom of movement of the user is adversely affected.

[0005] Furthermore, a binocular ophthalmoscope for viewing the retina of the human eye is also known (U.S. Pat. No. 5,841,509). To illuminate the retina there is a light source for example in the form of a light emitting diode, with light which is mixed into the beam path of the ophthalmoscope so that the illumination of the retina to be examined takes place by part of the optics of the ophthalmoscope. The light source is housed either directly in the housing of the ophthalmoscope or separate from it, the light in turn then being coupled in via an optical fiber. To avoid damage to the retina, the light source has only very low power. This known device is generally neither designed nor suited as a magnifying glass for viewing the working field or the surgical field.

[0006] The object of the invention is to avoid these defects. To achieve this object the magnifying glass is made according to claim 1 and the illumination means is made according to claim 10.

[0007] One special feature of the invention is that the light source is formed by several LEDs with a high illumination intensity of at least 2000 mcd, for example with an illumination intensity of at least 3000 mcd. The light of the individual LEDs is focussed at the focus by the focussing element which is assigned to the respective LED. The LEDs are supplied with power via a portable power supply unit which is located separately from the light source and is connected to it via a power supply cable.

[0008] In one especially advantageous embodiment of the invention, separately from the illumination means there is an actuating element which controls the illumination means by contact or by proximity, especially turns it on and off. This is especially important in particular in surgical applications with respect to hygiene and sterility to be maintained.

[0009] Developments of the invention are the subject matter of the dependent claims. The invention is detailed below using the figures on one embodiment.

[0010] FIG. 1 shows one possible embodiment of the magnifying glass as claimed in the invention as telescopic spectacles;

[0011] FIG. 2 shows another possible embodiment of the magnifying glass as claimed in the invention for attachment to a headband;

[0012] FIG. 3 shows a simplified section through the illumination means for use in the magnifying glass of FIGS. 1 and 2;

[0013] FIG. 4 shows the illumination means of FIG. 3 in a front view;

[0014] FIG. 5 shows another possible embodiment of the illumination means for use in the magnifying glass of FIGS. 1 and 2;

[0015] FIG. 6 shows in an individual representation and in a section a focussing lens for use in the illumination means.

[0016] In the figures a surgical microscope or a magnifying glass with double optics is generally labelled 1; it is especially, but not exclusively, suited for use in medicine, for example dentistry, microsurgery, etc.

[0017] The two optics 1 and 2 are conventionally provided on an adjustable adapter 3 with which the magnifying glass 1 can be attached selectively to spectacles 4 or to eyeglass frames to form telescopic spectacles or to another holder which is attached to the head of the user, for example to a headband.

[0018] Between the two optics 2 on the adapter 3 is an illumination means 6 which delivers a combined light beam 7 which illuminates the area viewed through the magnifying glass 1 or through the optics 2 (for example, surgical or viewing area).

[0019] FIG. 2 shows the illumination means 6 in detail. It consists in this embodiment essentially of a cylindrical housing 8 which has on the front side an arrangement of several lenses, i.e. in the embodiment shown of a total of three lenses 9 which form focussing optics and which are arranged uniformly offset around the center axis M of the housing 8 in a common plane perpendicular to this center axis. Within the housing 8 is a board 11 which with its surface sides is perpendicular to the center plane M and which on its side facing the lens arrangement 10 has several LEDs 12, the number of LEDs in the embodiment shown being equal to the number of lenses 9 and each LED being located coaxially or essentially coaxially to the optical axis of a lens 9.

[0020] The LEDs used are so-called ultra-bright LEDs, i.e. light-limiting diodes which have especially high efficiency, for example, an efficiency of 85% and thus at low electrical power consumption ensure high light output and have a light spectrum which corresponds to that of white light, i.e. for example daylight or approximately daylight.

[0021] Other advantages of the illumination means 6 are among others:

[0022] Due to the high efficiency of the LEDs used, the illumination means 6 has only low heat evolution. It can therefore be positioned with the magnifying glass closely in the area of the eyes and the nose of the user.

[0023] Furthermore at any time there is the possibility of focussing and adjusting the illumination means 6 by hand without the prior need to turn off and cool the illumination means 6.

[0024] The illumination means 6 can be produced with extremely small dimensions and with very low weight; this among others enables optimum positioning of the illumination means 6 on the magnifying glass 1 and comfortable wearing of the magnifying glass 1, for example, on eyeglass frames 4 or on a headband 5, since the total weight of the magnifying glass 1illumination means 6 is not noticeably influenced by the illumination means 6.

[0025] By attaching the illumination means 6 to the magnifying glass 1 the light beam 7 is automatically entrained when the user of the magnifying glass 1 moves his head so that the viewing field is always optimally illuminated.

[0026] As is indicated in FIG. 2 with the double arrow A, the board 11 with the LEDs there can be adjusted in the direction of the center axis M relative to the lens arrangement 10 for focussing or imaging the individual light beams at the focus in the viewing plane. Here then there is especially also the possibility of orienting the individual lenses 9 of the lens arrangement 10 with their optical axes such that the focusses of the then converging individual beams form an overall focus which optimally illuminates the viewing field or surgical field.

[0027] The LEDs are operated from a power supply unit 13 with a housing 14 which has small dimensions so that it can be comfortably held in a pocket, for example in the breast pocket of work clothing, a shirt or a blouse. The housing 14 contains at least one battery pack or battery 15, for example a replaceable battery or a rechargeable battery. Furthermore, in the housing there is control and monitoring electronics 16 which monitors especially the state of the battery 15 and displays the state or drain of the battery 15 by means of a LED display 16 on the top of the housing 14.

[0028] On the top of the housing 14 there are various terminals, in the embodiment shown a terminal 18 for a thin, very flexible cable 19 via which the illumination means 6 is connected to the power supply unit 13, and a terminal 20 for connection of a control line 21 which connects the power supply unit 13 or its electronics 16 to an actuating element 22, for example, to a momentary contact control switch, via which the illumination means 6 can be turned on and off by touching when the power supply unit 13 is turned on.

[0029] The actuating element 22 is made such that it can be comfortably attached for example by means of a clip which is not shown or in some other suitable way to the desired location on the clothing of the user of the magnifying glass 1 such that this actuating element 22 can then be actuated by being touched for example with the arm, wrist, elbow, etc. and thus it is possible to turn the illumination means 6 on and off without using the hand; this is very important especially in surgical applications with respect to the hygiene and sterility to be maintained.

[0030] On the top of the housing 14 there is furthermore a central switch 23 with which the power supply unit overall can be turned on and off. The weight of the illumination means 6 is for example 6 grams. With conventional batteries 15 a long operating life, for example at least 40 hours, can be reached until it is necessary to replace the battery.

[0031] The illumination means 6 is not only small and light, but this illumination means and the pertinent power supply unit 13 are also invulnerable to impacts. The size of the housing 14 corresponds for example to the size of a pack of cigarettes or half a pack of cigarettes.

[0032] Because it is also possible to use replaceable batteries, i.e. those which cannot be recharged or regenerated, the invention can be used especially wherever battery chargers are not available or their use is not feasible.

[0033] It was assumed above that the lens arrangement 10 is formed by three discrete lenses 9. But of course it is also fundamentally possible to use, instead of individual lenses, a multiple lens in which the individual lenses are combined into a monolithic multiple lens. Furthermore, it is also possible to use a lens common to all the LEDS instead of several individual lenses or lens elements. In the embodiment shown the lenses 9 are shown as optical convergent lenses. Of course, also other focussing elements are conceivable as individual lenses or lens arrangements.

[0034] FIG. 5 shows as another possible embodiment in a partial representation a board 11 on an illumination means 6a. In this illumination means, LEDs in the form of SMDs are used which enable a very dense arrangement on the board 11 so that in this version the individual light beams of a plurality of these LEDs 12a can be optimally focussed by means of a single optical focussing element at the focus of the common light beam 7. As shown in FIG. 5, in this version the LEDs 12a are arranged in several rows and columns so that the LEDs with their light-emitting active layer lie a quadratic grid so that illumination of the working area or viewing area as uniform as possible in all directions takes place.

[0035] The described arrangement of the LEDs enables illumination of the working area or viewing area as uniform as possible in all directions.

[0036] LEDs 12 or 12a with the illumination means 6 turned on are operated for example continuously. But basically there is also the possibility of operating the LEDs 12 or 12a pulsed, for example with a frequency of 100 Hz, by changing the pulse width also control of the light intensity then being possible.

[0037] FIG. 6 shows in a simplified representation and in a section another possible version of the focussing lens 9a which is used instead of the focussing lens 9. The focussing lens 9a is an aspherical lens which is produced by pressing out of a suitable optical material, for example a plastic material which is suitable for optical lenses. The particular feature of the focussing lens 9a is that it has one flat side 24 and one curved side 25 and is made aspherical on the curved side 25, i.e. with a radius of curvature which is smaller in the area of the optical axis and increases as the distance from the optical axis 26 increases. Using this aspherical focussing lens allows better concentration also of the edge beams 27 and thus improves the light output; this is especially important when using LEDs 12 and 12a as the light source.

[0038] The invention was described above using embodiments. It goes without saying that numerous other changes and modifications are possible without departing from the idea underlying the invention. Thus it is also possible for example to use LEDs, instead of the lenses 9 or the lens arrangement 10, which are provided with a built-in optical element which focusses the light beam.

[0039] Furthermore it is also possible to use, instead of individual LEDs 12 and 12a, multiple LEDs which have several light-emitting emitters on a semiconductor chip or bar. Here it is then also especially possible to provide several such chips and then to combine the individual beams of these chips into a common light beam which illuminates the respective viewing or working area.

[0040] Furthermore, it is also possible when using several LEDs or one or more multiple LEDs to combine the light of these light sources via optical elements, for example via lenses or lens optics, via optical fiber optics, etc. in an area to be illuminated or at a common focal point or to concentrate the light via optical elements, for example via the aforementioned optical elements or optical fibers at the focal point of common focussing optics or a lens so that then only a single optical focussing or projection system is necessary in spite of a plurality of LEDs.

[0041] The illumination means 6 or 6a was described above in conjunction with the magnifying glass 1. But basically the illumination means is also suitable for other purposes where it is a matter of illuminating smaller areas, for example as the illumination means in a microscope.