DE102008005706B4 - Medical device with an annular illumination - Google Patents

Abstract

Medical device with ring-shaped lighting, preferably of the inside of the eye, which uses a funnel-shaped element in the lighting arrangement for beam shaping, the lighting arrangement - having an inner part (1) which is an essentially plane-parallel plate, from whose contact surface (3) a conical core (4) protrudes, the outer surface of which is reflective, at least one circular ring of the material of the inner part (1), which is directly adjacent to the mirrored outer surface of the core (4), is transparent, - furthermore has an outer part (2) which a body (7) which has a hole (8) which has a barrel-shaped wall, the outer surface of which is reflective, the hole (8) having a smaller opening in a coupling surface (11) and the hole (8) a larger one Has opening in a joining surface (6), characterized in that the contact surface (3) of the inner part (1) with the joining surface (6) of the outer part (2) s o is connected that an optical axis of the nucleus ...

Description

The invention relates to a medical device with an annular illumination, which uses a funnel-shaped element for beam shaping.

In US 2004 0131157 A1 . US Pat. No. 6,542,307 B2 . US 2007 0064202 A1 and US 2006 0215401 A1 It is shown that a funnel-shaped element can be used very successfully for various application areas with great success. The advantage of such an element is compactness, efficiency in the conversion of the light flux emitted by the light source into a light flux accepted by the subsequent optical system. It is intended to achieve a homogenization of the radiation at an angle and / or in the field.

Some optical systems in medical devices and in other applications require a circular field distribution and homogeneous angular distribution simultaneously to z. B. to realize a pupil separation. The known solution to this problem is to hide radiation by means of a circular aperture.

Out GB 2 077 428 A . EP 0 244 788 A2 and DE 202 06 829 U1 Solutions are known to use instead of a funnel-shaped a barrel-shaped element.

The invention is intended to solve the problem of providing a medical device with an annular illumination, which is inexpensive to produce. It is intended to transform the light radiation of a light source as efficiently as possible and to emit it with a predetermined and as homogeneous as possible angular and field distribution.

The solution of the problem is achieved with the features of claim 1. The dependent claims 2 to 9 are advantageous embodiments of claim 1. According to the invention, the proposed solution consists of two separate parts which are assembled together: an inner part and an outer part.

The outer part is a body in which a rotationally symmetrical, half-barrel-shaped recess is located, which is also referred to as a concentrator in connection with the beam shaping of a light source. The generatrix of the concentrator is preferably a Bezier curve with an input radius and an output radius which carries a reflective coating or is self-reflective.

The inner part is a cone-shaped core, which protrudes from a flat contact surface. The generatrix of the core is preferably a Bezier curve of the type which carries a reflective coating or is self-reflective. The material adjacent the core of the inner part must be transparent to the radiation to be transmitted. Preferably, the inner part is completely transparent and only the cone-shaped core is surface-mirrored.

beschrieben, wobei r₁ und r_n die entsprechende Koordinaten ((x₁, y₁), (x_n, y_n)) für die Anfangs- und Endkontrollpunkte sind. N_i,n(t) ist das Bernstein Polynom und w_i ist das Gewicht. Die Polynomordnung n ist ≥ 2, vorzugsweise > 2 und liegt insbesondere zwischen 3 und 5.The rational Bezier curves are given by the formula

where r ₁ and r _{n are} the corresponding coordinates ((x ₁ , y ₁ ), (x _n , y _n )) for the start and end control points. N _{i, n} (t) is the amber polynomial and w _i is the weight. The polynomial order n is ≥ 2, preferably> 2, and is in particular between 3 and 5.

By dimensioning the generatrices of the outer part and the inner part maximum angles in the range of greater than 0 ° to 90 ° are optimized in terms of angular homogeneity. The ring lighting in the field is ensured by the inner part, creating a sharply defined, light-free circle in the field inside. Optimization criterion can also be the homogeneity of the field. The optimization is done with the help of standard optical computer programs, eg. ZEMAX.

The illumination element for the annular illumination is used in particular in a fundus camera and in a transcorneal retinal illumination, but is also applicable to other illumination purposes in which an annular illumination is to be achieved.

The lighting element for the annular illumination is highly efficient and provides a defined and homogeneous angular distribution. However, the core and the hole of the lighting element can also have a polygon shape (for example, a triangle, a rectangle, a hexagon) or an arbitrary shaping, wherein the shapes result in corresponding annular illumination fields.

The lighting element is preferably operated in conjunction with an LED light source, but may also be used with another light source.

The invention will be described below with reference to figures. Show it

1 : Side view of the inner part

2 : Top view of the inner part with a radially symmetric core

3 : Side view of the outer part

4 : Top view of the outer part with a radially symmetrical hole

5 : Assembly drawing of the lighting element with an LED chip

6 : Representation of the shape of the freeform surfaces

7 : Representation of the beam path achieved with the free-form surfaces

8th : Representation of the field intensity at the output of the illumination element (near field)

9 : Representation of the intensity of the angular distribution at the output of the illumination element, measured in the far field

10 : Top view of the inner part with a square core

11 : Top view of the outer part with a square hole

1 shows an inner part 1 in a side view, which is cast from a transparent material. From the middle of a flat contact surface 3 a cone-shaped core protrudes 4 out. The core 4 has a lateral surface, which is a cone-shaped freeform surface, which is mirrored. The materials used are preferably PM, MA, PC or ZEONEX. The mirroring is done by an aluminum coating, which is covered with a scratch-resistant protective layer. Furthermore, the inner part has 1 at a distance from the core 4 arranged blind holes 5 in the contact area 3 ,

It is important that at least one annular region of the contact surface 3 that is between the core 4 and the blind holes 5 lies, has an optical quality. Likewise, the contact surface 3 opposite surface have an optical quality.

2 shows the inner part 1 in the plan view.

3 shows an outer part 2 in a side view. In the middle of a body 7 there is a hole 8th with a half-barrel-shaped wall, the mirrored surface of which is a free-form surface 9 is. The hole 8th has a smaller opening in a coupling surface 11 as light entry and a larger opening in a joint surface 6 as light emission. At a distance to the larger opening of the hole 8th are cones 10 arranged, which are dimensionally determined so that the pins 10 of the outer part 2 in the blind holes 5 of the inner part and the optical axis 14 the freeform surface of the core 4 exactly to the optical axis 14 the free-form surface of the hole 8th is positioned.

Every pin 10 forms with his blind hole 5 a snap-in connection when the inner part 1 and the outer part 2 be joined together.

The parts can also be connected to each other by welding or gluing. If the freeform surfaces are rotationally symmetrical, for example, an annular groove in combination with a matching counterpart fulfill the same function as a blind hole 5 and cones 10 ,

4 shows the outer part 2 in the plan view.

5 shows an assembly drawing of the lighting element, wherein the contact surface 3 of the inner part 1 with the joining surface 6 of the outer part 2 connected is. Furthermore, at the coupling surface 11 a carrier element 13 attached, which is an LED component 12 as a light source. The LED component 12 becomes the optical axis 14 mounted aligned of the lighting element.

r₁ und r_n sind die entsprechende Koordinaten ((x₁, y₁), (x_n, y_n)) für Anfangs- und Endkontrollpunkte. N_i,n(t) – ist Bernstein Polynom und w_i – das Gewicht.Hereinafter, the individual parts for a lighting element which is intended for a fundus camera will be described on a first example. The rational Bezier curves are given by the following formula:

r ₁ and r _n are the corresponding coordinates ((x ₁ , y ₁ ), (x _n , y _n )) for start and end control points. N _{i, n} (t) - is amber polynomial and w _i - the weight.

In the example n = 3 is chosen, therefore have the inner part 1 and the outer part 2 one checkpoint each in the middle (r ₂ ).

The inner part 1 has the following parameters
Input radius 0.0 mm Weight 1
Total length 9.00 mm
Output radius 1.00 mm Weight 1
Check point position 1.00 mm (to the input radius); Radius 1.00 mm; Weight 0.432
Location of the entrance radius to the entrance of the outer part 1 mm

The outer part 2 has the following parameters:
Input radius 1,288 mm Weight 1
Total length 10.00 mm
Output radius 3.5 mm Weight 1
Check point position 2,823 mm; Radius 3.601 mm; Weight 0.934959

The light source is an LED component 2 mm × 2 mm is used, which consists of 2 × 2 1 mm ² LEDs.

6 shows the freeform surfaces and 7 the beam path obtained with these free-form surfaces.

8th shows the intensity profile of the field distribution directly at the output of the lighting element and 9 shows the angular distribution of the radiation at the output of the lighting element, measured in the far field. The example according to the 6 and 7 was optimized for an angle of ± 25 °. The light transmission at this angle is about 80% with an ideal mirror layer.

A second example of a lighting element intended for transcorneal retinal illumination will be described below.

The light source used is an LED with a luminous area of 2 mm × 2 mm, consisting of 2 × 2 1 mm ² LEDs.

The freeform surface 9 of the outer part 2 has the following parameters: input radius 2.28 mm with a weight of 1.225, total length 3.83 mm and output radius 3.5 mm with a weight of 1.00, the control point position is 0.541 mm, with a radius of 4.00 mm and weighing 1.00.

The reflection surface of the core 4 of the inner part 1 has the following parameters:
Entry radius 0,0 mm with a weight of 1.00, total length 2.94 mm and a starting radius of 2.00 mm with a weight of 1.00, wherein the control point position 1.533 mm (relative to the input radius) with a radius of 1 , 00 mm and weighing 1.00.

The location of the input radius of the inner part 1 to the entrance of the outer part 2 is 0.89 mm. This example has been optimized for an angle ± 60 °.

The light transmission at this angle is about 71%, assuming an ideal mirror layer.

10 shows the top view of the inner part 1 , which in the example a square core 4 having. 11 shows the top view of the outer part 2 with a square hole 8th which belongs to the part 1 to 10 is dimensioned.

LIST OF REFERENCE NUMBERS

1

inner part

2

outer part

3

contact area

4

core

5

blind

6

joining surface

7

body

8th

hole

9

Free-form surface

10

spigot

11

coupling surface

12

LED component

13

support element

14

Optical axis

I

intensity

R

radius

n

polynomial

r → (t)

Direction vector of the Bezier curve

r → _i

Bases of the Bezier curve

i

Counter 1 ... n

Claims (9)

Medical device having an annular illumination, preferably an eye interior, which uses in the illumination arrangement a funnel-shaped element for beam shaping, wherein the illumination arrangement - an inner part ( 1 ), which is a substantially plane-parallel plate, from the contact surface ( 3 ) a cone-shaped core ( 4 protruding, wherein at least one circular ring of the material of the inner part ( 1 ), which directly to the mirrored outer surface of the core ( 4 ), is transparent, - furthermore an outer part ( 2 ), which is a body ( 7 ) that is a hole ( 8th ), which has a barrel-shaped wall, whose lateral surface is reflective, wherein the hole ( 8th ) has a smaller opening in a coupling surface ( 11 ) and the hole ( 8th ) a larger opening in a joint surface ( 6 ), characterized in that the contact surface ( 3 ) of the inner part ( 1 ) with the joining surface ( 6 ) of the outer part ( 2 ) is connected so that an optical axis of the core ( 4 ) is in conformity with an optical axis of the hole, and that the transparent annulus of the material of the inner part ( 1 ) has at least one outer diameter which is equal to or greater than the diameter of the larger opening in the joining surface ( 6 ) of the outer part ( 2 ), so that a homogeneous light distribution over the transparent annulus is achievable. Medical device according to claim 1, characterized in that the reflective outer surface of the Kerns ( 4 ) and / or the reflective surface of the hole ( 8th ) is / are mirrored. Medical device according to claim 1, characterized in that the reflective outer surface of the core ( 4 ) and / or the reflective surface of the hole ( 8th ) is in each case a freeform surface. Medical device according to claim 1, characterized in that the contact surface ( 3 ) Has recesses and / or projections and the joining surface ( 6 ) has matching counterparts to the recesses and / or projections, so that after joining the parts of the optical axis of the core ( 4 ) with the optical axis of the hole ( 8th ) is in agreement. Medical device according to claim 1, characterized in that the coupling surface ( 11 ) of the outer part ( 2 ) is connected to a surface of a support element, which carries a light source, so that the main radiation direction of the light source with the optical axis of the hole ( 8th ) as well as with the optical axis of the core ( 4 ) is in agreement. Medical device according to claim 5, characterized in that the light source is an LED or LED assembly, which consists of a matrix of several individual LED, or a temperature radiator. Medical device according to claim 1, characterized in that the core ( 4 ) has a rotationally symmetric conical shape or is conically polygonal. Medical device according to claim 1, characterized in that the hole ( 8th ) has a rotationally symmetrical frusto-conical shape or is frustoconical polygonal. Medical device according to claim 1, characterized in that the lateral surface of the core ( 4 ) and / or the lateral surface of the hole ( 8th ) by rational Bezier curves with the formula

where r ₁ and r _{n are} the corresponding coordinates ((x ₁ , y ₁ ), (x _n , y _n )) for the start and end control points N _{i, n} (t) is the amber polynomial and w _i is the weight.

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