WO1993022965A1

WO1993022965A1 - Combined prism head for slit lamps

Info

Publication number: WO1993022965A1
Application number: PCT/DE1993/000408
Authority: WO
Inventors: Karl-Heinz Wilms
Original assignee: G. Rodenstock Instrumente Gmbh
Priority date: 1992-05-08
Filing date: 1993-05-10
Publication date: 1993-11-25
Also published as: DE4215128C2; DE4215128A1

Abstract

An ophthalmologic slit slamp has an observation device and a slit projector (Q, SP) whose light is deflected over 90° by a deflector (P) and is projected on the eye. The invention is characterized by a beam-deflecting optic element (SN) which can be introduced into the path of the beam, upstream of the deflector. When said optic element is introduced into the path of the beam, it deflects the light beam in such a way, instead of the deflector, that the thus deflected light beam encloses an angle of preferably 15° to 25° with the axis of the light beam originally deflected over 90°.

Description

Combined prism head for slit lamp

Description

Technical field

The invention relates to a slit lamp for eye examination with an observation device and a slit projector, the light of which is deflected by a deflection device by 90 degrees and projected onto the eye.

For the eye examination, light sources are required which illuminate the eye or areas of the eye with a particularly adjustable light intensity such that the eye or the area to be examined is illuminated sufficiently brightly without damaging the eye, so that in particular direct observation with the aid of from conventional observation devices, such as Microscopes (i.e. slit lamp microscopes), cameras or similar eye examination devices can be carried out.

State of the art

A device which is very widespread for examining the eye is the so-called slit lamp, which has an observation device, such as a binocular slit lamp microscope, and a slit projector. The German publications 1 278 757 and 2 000 682 and US Pat. No. 3 _: 405 994 may be mentioned only as examples of publications in which slit lamps are described. The slit projector of slit lamps is usually designed in such a way that the light generated by a lamp is directed through a collector system to a slit diaphragm whose dimensions are adjustable. By a commonly aplanatic and aspherical Beleuc ^'htungslinse an image of the gap is generated, the field monitoring the Untersu¬ illuminated during examination. Possibilities of regulation by changing the gap width enable the observation of individual visual cells in the chamber angle, corneal nerves, lens opacification, vitreous opacification, even the blood cells rolling in the vessels, etc.

The examination of the lateral parts of the chamber angle of the eye is of particular interest. For this purpose, an inclination of the horizontally placed slit image is necessary to illuminate the lateral eye areas. Without such an inclination of approximately 15 ° to 20 ° relative to the illuminating beam direction perpendicular to the eye, a slit-microscopic examination of these areas cannot be carried out.

Observing the eye with direct lighting, i.e. if the direction of observation and illumination coincides, although this is advantageous in a number of examinations, on the other hand disturbing reflections can occur on the uppermost eye layer, which at least severely obstruct the eye examination.

It would therefore be desirable to be able to vary the so-called vertical angle of incidence, ie the (vertical) angle between the axis of the light beam emerging from the slit projector and the optical axis of the observation device. Slit lamps are now available in which the slit projector is provided with a 90 ° deflection prism. A variation of the vertical angle of incidence is not possible with these slit lamps or only by exchanging the deflection head of the slit projector.

From the patent literature it is also known, by shifting a Umlenkel ements ^axis' in the direction of the Augen¬ (U.S. Patent No. 3,405,994), or approximately perpendicular thereto (DE-AS 1,287,757) or by rotation of the deflecting head (DE-AS 2 000 682) to vary the so-called vertical angle of incidence.

In another type of slit lamp - reference is made to DE-OS 23 06 595 - the slit lamp microscope side facing the eye is additionally provided with an optical prism which, with a corresponding rotational orientation, has a vertical observation angle range of approximately 20 ° with fixed slit lamps ¬ microscope enables.

In all of the slit lamps known from the prior art, however, the mechanical outlay is in no reasonable relation to the lighting successes which can be achieved thereby.

Presentation of the invention

The invention is based on the object of developing a slit lamp for eye examination with a slit projector, the light of which is deflected by a deflection device by 90 ° and projected onto the eye, in such a way that continuous illumination of the fundus enables the simplest possible way becomes, so that the need for cumbersome mechanical pivoting devices between the slit projector and the slit microscope is avoided and, furthermore, the manufacturing costs of such an arrangement can be considerably reduced.

A solution to this problem is given in claim 1. Further developments of the invention are specified in the subclaims.

The invention is particularly characterized in that a slit lamp for eye examination with an observation device and a slit projector, the light of which is deflected by a deflection device by 90 degrees and projected onto the eye, is further developed in that a beam-deflecting optical ele in the beam direction in front of the deflection device ¬ ment can be introduced into the beam path, which, if it is introduced into the beam path, deflects the light beam instead of the deflection device in such a way that it encloses an angle <> 0 degrees with the beam axis of the light beam originally deflected by 90 degrees.

As a rule, a slit lamp projector consists of a light source, a condenser, a slit diaphragm and various imaging lenses, which can in particular be achromatic lenses, which guide the parallel light beam onto a 90 ° deflection prism that directs the exit additive beam onto the object to be illuminated. According to the invention, a beam-deflecting optical element, which is preferably a long, thin mirror, is introduced into the beam path in front of the deflecting prism. Of course, other optical deflection elements are also conceivable, such as prisms or Like. The mirror can be inserted, for example, as a functional unit in the beam path, so that it occupies a defined position in the slit lamp projector head.

The beam-deflecting optical element should advantageously reflect as little heat radiation as possible.

Brief description of the drawing

The invention is described below by way of example without limitation of the general inventive concept by means of exemplary embodiments with reference to the drawing, to which reference is expressly made with regard to the disclosure of all details according to the invention not explained in detail in the text. Show it:

Fig. 1 shows the basic arrangement of assemblies

Slit projector in which a mirror device according to the invention is used as the beam-deflecting optical element,

2 shows the mirror device according to the invention in combination with an achromatic lens

Fig. 3 shows a mirror device according to the invention in a) slidable, b) rotatable and c) pivotable embodiment

Representation of exemplary embodiments The slit projector shown in FIG. 1 has a light source Q, the light of which is bundled by a concave mirror S _R, preferably emitted in the direction of a condenser K. The light beam passing through the condenser K passes through a slit diaphragm S _p and then passes through an imaging lens E and then an achromatic lens A-. The imaging lens E and the achromatic lens A. form an optical unit. In conventional slit projectors, the beam hits another achromat A «of the standard prism head, is then deflected by 90 ° through a deflecting prism P and leaves the slit projector. According to the invention, a beam tilting mirror S "can be introduced into the prism head in the beam direction in front of the deflecting prism P, said mirror reflecting the light beam coming from the light source Q in such a way that it encloses an angle of approximately 15 ° to 20 ° with the light beam that excludes the deflection prism P exits if _: the mirror S _{M is} removed from the beam path.

An achromat A ₃ for the inclined beam direction, makes the outgoing light beam inclined for eliminating the chromatic variation.

FIG. 2 shows an embodiment with only one shared achromatic lens in connection with the beam tilt mirror S _N. Here, the negative member of the achromat A _{3b is} connected to the beam tilt mirror S _N , so that the negative member A _{3 is also} moved when the beam tilt mirror S is adjusted. The beam reflected at the beam tilt mirror S _N then passes through the positive element A_ of the achromatic lens

^A 3 ^*

FIG. 3 shows various possibilities which allow the inclination of the beam tilt mirror S "into the optical beam path of a slit projector head, which essentially consists of the deflection prism P,. The normal slit projector light beam is dotted in FIGS. 3a, 3b and 3c and the light beam deflected by the beam tilt mirror S is shown in broken lines.

In FIG. 3a, the beam tilting mirror S _{N is} inserted into the light beam of the slit lamp from the outside, preferably from the side, so that it occupies a defined position in the light beam. In FIG. 3a, however, the beam tilting mirror S _{N can be} pushed in from the back of the prism head for technical drawing reasons. The optical element, for example an achromatic, is in a fixed connection with the deflecting prism P. In a further preferred embodiment, which is not shown in this context, the beam tilt mirror S _{N is combined} with the optical element 0 _p in the Beam path inserted so that the beam tilt mirror S _N and optical element 0 _{p form} a unit.

In FIG. 3b, the beam tilt mirror S _{N is} mounted so that it can be rotated in the center of the light beam of the slit projector, so that it can be tilted from a vertical position, which only slightly influences the light beam, into a tilted position, so that the light beam can be moved through optical element firmly connected to the slit projector head can pass through. The folding mechanism is to be operated from outside the slotted projector head. In this embodiment too, the optical element 0 _{p is} firmly connected to the prism P. FIG. 3c shows a further embodiment of a slit projector head according to the invention, in which the beam tilt mirror S z. B. together with the optical element 0 _p can be pivoted into the light beam path. The optical element 0 _p and the beam tilt mirror S "form a functional assembly. However, the mirror S _N can advantageously also be pivoted into the beam path from the side or from the front. In FIG. 3c, however, for reasons of drawing technology, the beam tilt mirror S _{N is} shown pivotable into the beam path from the rear of the prism head. Of course, the beam tilt mirror S _N can also be pivoted into the beam path alone.

Of course, other mechanisms are also conceivable by means of which optical elements for deflecting a light beam can be introduced into the light beam path of a slit projector, for example by inserting a separate component.

With the tilting mirror according to the invention, a simple way has been found to manipulate the beam path of a slit projector in such a way that the light beam incident in the eye enables an angle typically between 15 ° and 25 ° relative to the horizontal.

Claims

Patent claims

1. Slit lamp for eye examination with an observation device and a slit projector, the light of which is deflected by a deflection device by 90 degrees and projected onto the eye, characterized in that a beam-deflecting optical element can be introduced into the beam path in the beam direction in front of the deflection device which, when introduced into the beam path, deflects the light beam instead of the deflection device in such a way that it forms an angle <> 0 degrees with the beam axis of the light beam originally deflected by 90 degrees.

2. Slit lamp according to claim 1, characterized in that the angle between the deflected light beams is less than 45 ° and preferably 15 ° to 25 °.

3. Slit lamp according to claim 1 or 2, characterized in that the optical element reflects as little heat radiation as possible.

4. Slit lamp according to one of claims 1 to 3, characterized in that the optical element is a thin, narrow, long mirror.

5. Slit lamp according to one of claims 1 to 4, characterized in that the optical element is rotatably mounted about an axis arranged perpendicular to the beam direction ^' .

6. Slit lamp according to one of claims 1 to 5, characterized in that the optical element can be pivoted into the beam path.

7. Slit lamp according to one of claims 1 to 6, characterized in that the optical element is preferably insertable from the side into the beam path.

8. Slit lamp according to one of claims 1 to 9, characterized in that the optical element is adjustable such that the deflected light beam on the optical element assumes any angle within the specified limits.

9. Slit lamp according to one of claims 1 to 8, characterized in that the deflection device is a Unlenkpris a.

10. Slit lamp according to one of claims 1 to 9, characterized in that in each case two achromatic lenses are introduced in the radiation-proof of the light beam deflected by 90 ° and deflected with the aid of the optical element.

11. Slit lamp according to claim 10, characterized in that the achromatic lens, which is attached in the beam direction in front of the optical element, forms an optical unit with an imaging lens.

12. Slit lamp according to one of claims 1 to 9, characterized in that in the beam direction before optical element the negative member and after the optical element the positive member of an achromatic lens is attached.

13. Slit lamp according to claim 12, characterized in that the negative member together with the optical element is displaceable relative to the positive member.