WO2008087012A1

WO2008087012A1 - Apparatus for homogenizing light and apparatus for producing a linear intensity distribution in a working plane

Info

Publication number: WO2008087012A1
Application number: PCT/EP2008/000273
Authority: WO
Inventors: Aleksei Mikhailov; Vitalij Lissotschenko
Original assignee: Limo Patentverwaltung Gmbh & Co. Kg
Priority date: 2007-01-15
Filing date: 2008-01-15
Publication date: 2008-07-24
Also published as: WO2008087012A8

Abstract

Apparatus for homogenizing light, comprising a first lens array (9) with a plurality of lenses which are arranged next to one another in a first direction (X), wherein the light to be homogenized can pass through the first lens array (9), and comprising a second lens array (10) with a plurality of lenses which are arranged next to one another in the first direction (X), wherein light which has passed through the first lens array (9) can pass through the second lens array (10) and wherein the centre-to-centre spacing (P2) of the second lens array (10) is different from the centre-to-centre spacing (P1) of the first lens array (9) such that light components which have passed through different lenses of the second lens array (10) are mutually superposed behind the second lens array (10) in the first direction (X).

Description

"Device for the homogenization of light and device for generating a linear intensity distribution in one

Working level "

The present invention relates to a device for homogenizing light according to the preamble of claim 1 and to an apparatus for producing a linear intensity distribution in a working plane according to the preamble of claim 10.

Definitions: In the propagation direction of the light to be influenced, the mean propagation direction of the light means, especially if this is not a plane wave or at least partially divergent. By light beam, sub-beam or beam is meant, unless expressly stated otherwise, an idealized beam of geometric optics, but a real light beam, such as a laser beam with a Gaussian profile, which has no infinitesimal small, but an extended beam cross-section. Pitch means the distance of the centers of the lenses of an array from each other in the direction in which the lenses in the array are juxtaposed.

Devices of the type mentioned are from the WO

2005/085934 known. Behind the two lens arrays, in the device for homogenization described therein, a comparatively wide field lens is arranged in the direction in which the lenses are arranged next to one another in the array, which can superimpose the light which has passed through the lens arrays in a working plane. If a very long line-shaped intensity distribution is to be generated in the working plane, the field lens would have to be disproportionately wide. This raises manufacturing problems and may lead to Influencing the quality of the intensity distribution due to lens aberrations. Furthermore, the production of such a lens is associated with high costs.

The problem underlying the present invention is the provision of a device for the homogenization of light of the type mentioned above and a device for generating a linear intensity distribution in a working plane of the type mentioned which are constructed simpler and / or more effective.

This is inventively achieved by devices of the type mentioned above with the characterizing features of claims 1 and 10. The subclaims relate to preferred embodiments of the invention.

According to claim 1, it is provided that the at least one second center distance of the second lens array is different from the at least one first center distance of the first lens array, so that portions of the light to be homogenized passed through different lenses of the second lens array are spaced behind and in the propagation direction of the light are superposed with each other to the second lens array in the first direction. As a result of this configuration of the lens arrays, it is possible to dispense with a field lens for superposing the portions of the light which have passed through individual lenses, so that the device is constructed more simply and effectively.

It can be provided that the at least one second

Center distance of the second lens array is smaller than the at least one first center distance of the first lens array. Alternatively For example, the center distance of the second lens array could be greater than the at least one first center distance of the first lens array

There is the possibility that the at least one second center distance of the second lens array is less than 10 μm from the at least one first center distance of the first

Lens arrays are different. In this case, the at least one second center distance of the second lens array may be less than 5 .mu.m, in particular by 0.1 .mu.m to 3 .mu.m, preferably by 0.5 .mu.m to 1.5 .mu.m, for example by about 1 .mu.m from the at least one first center spacing of the first lens array differ. Even such a small difference between the pitch of the first and second lens arrays can cause a complete superposition of the portions of the light that have passed through individual lenses.

It may further be provided that at least some of the lenses of the second lens array are different from each other. In this case, at least the lenses arranged in the edge regions of the second lens array can be asymmetrical, in particular with respect to a central Y-Z plane. By such a design, the superposition of the parts of the light passed through individual lenses can be supported.

In particular, in each case groups of identical lenses can be provided which correspond to one another in terms of shape and size, the lenses of different groups being different from one another. By the same in groups with each other lenses manufacturing costs can be reduced.

The device for producing a linear intensity distribution in a working plane according to claim 10 characterized by an inventive device for homogenization.

Further features and advantages of the present invention will become apparent from the following description of preferred embodiments with reference to the accompanying drawings. Show in it

Fig. 1 a is a schematic partial view of a first

Embodiment of an inventive device for generating a linear intensity distribution in a working plane;

FIG. 1 b schematically shows an intensity distribution in a first plane of the device according to FIG. 1 a; FIG.

FIG. 1 c schematically shows an intensity distribution in a second plane of the device according to FIG. 1 a; FIG.

FIG. 2 shows a schematic partial plan view of an embodiment of a device according to the invention for homogenizing light; FIG.

FIG. 3 is a schematic plan view of a first detail of the device according to FIG. 2; FIG.

FIG. 4 is a schematic plan view of a second detail of the device according to FIG. 2; FIG.

Fig. 5a shows schematically an intensity distribution in a first

Plane of a second embodiment of a device according to the invention for generating a linear intensity distribution in a working plane;

5b schematically shows an intensity distribution in a second plane of the device according to FIG. 5a. In the figures, Cartesian coordinate systems are shown for clarity.

In Fig. 1 a schematically a plurality of light sources 1 can be seen, which have a square outline and a central small circular light emitting portion 2. In these

Light sources 1 may be, for example, ends of optical fibers in corresponding holders. For example, the light of one or more lasers can be coupled into these optical fibers on the input side. The light emitting sections 2 send out light beams 3 in the Z direction or into the plane of drawing of FIG. 1a.

The arrows 4 in Fig. 1 a and in each other of the figures are intended to indicate that in the X direction more light sources 1 or more light beams 3 may be present as shown. Due to the geometry of the light sources 1, the light emitting

Section 2 in Fig. 1 a separated by comparatively large spaces.

By not shown, known from the prior art first Strahlumformmittel can be achieved that the interstices in the Y direction between light beams 3, emanating from different light emitting portion 2, are reduced. FIG. 1 b schematically shows an intensity distribution in the propagation direction Z of the light behind such compressing beam-shaping means. In this intensity distribution, the distances between the individual light beams 3 in the Y direction are reduced, whereas the distances in

X direction were maintained.

By further, also not shown, for example, from the prior art according to EP 1 006 382 known, second Beam reforming means can be achieved, the single of the light beams 3 are rotated relative to each other. In particular, the light beams 3 arranged next to each other in the Y direction are rotated through 90 ° by the second beam shaping means, so that they are subsequently arranged next to one another in the X direction. Fig. 1 c shows schematically the intensity distribution in the propagation direction Z of the light behind such rotating beam forming means. FIG. 1 c shows that a plurality of light beams 3 are arranged close to each other in the X-direction.

In Fig. 2 is a schematic representation of a device 5 according to the invention

Homogenization shown. In this device 5 enters a light distribution, which corresponds for example to the intensity distribution of FIG. 1 c. In FIG. 2, reference numerals a, b, c, d, e and f denote individual sections of the device 5. The arrows 4 in FIG. 2 are intended to indicate that more sections than in the X-direction can be present in the X-direction.

Above the device 5, an intensity distribution 6 is shown schematically in Fig. 2, which corresponds to that in Fig. 1 c and the densely arranged side by side light beams 3 is intended to illustrate. The emerging from the device light beams 7 are in

X-direction superimposed in a working plane 8 with each other. This achieves good homogenization of the light in the X direction.

3 shows the sections c and d of the device 5. The device 5 comprises a first lens array 9 and a second lens array 10, which are arranged one behind the other in the propagation direction Z of the light. The lens arrays each comprise a plurality of cylindrical lenses 1 1, 12 arranged side by side in the X direction, the cylinder axes of which extend in the Y direction. The cylindrical lenses 1 1 of the first lens array 9 correspond to each other in size and shape. The cylindrical lenses 12 of the second lens array 10 of the sections c and d of the device 5 also correspond in size and shape, so that they form a first group of identical lenses. Here, the center distance Pi of the first lens array 9 is slightly larger than the center distance P _{2 of} the second

Lens arrays 10.

Due to these different center distances Pi, P ₂ , a light beam 3a, which has passed through the center of a cylindrical lens 1 1 of the first lens array 9, does not pass through the center of the cylindrical lens 12 of the second lying behind in the Z direction

Lens arrays 10, but something in addition to the middle through this. As a result, this light beam 3a is slightly deflected laterally in the X direction and leaves the second lens array 10 of the device 5 at an angle other than 0 ° to the Z direction as the light beam 7a. This leads to the already described superposition of

Light rays 7 in the working plane. 8

4, the sections e and f of the device 5 are shown in FIG. 4. The first lens array 9 is designed in the sections e and f of the device 5 as well as in the sections c and d. The design of the second lens array 10 differs in sections e and f from those in sections c and d. In sections e and f, the cylindrical lenses 13 of the second lens array 10 are asymmetrical with respect to a central Y-Z plane. In particular, the cylindrical lenses 13 are in the sections e and f on their middle

4 thinner than on its side facing the edge or on the right in FIG. 4. The cylindrical lenses 13 of the second lens array 10 of the sections e and f of the device 5 correspond to one another in terms of size and shape, so they have a second group of form same lenses. However, the cylindrical lenses 1 3 of the first group in the sections c and d are different from the cylindrical lenses 13 of the second group in the sections e and f.

Due to the asymmetrical structure of the cylindrical lenses 13 in the edge regions of the device 5, the superposition effect in the

Working level supported. The non-illustrated cylindrical lenses in the sections a and b of the second lens array 10 may also be designed asymmetrically, and they are also thinner on its side facing the middle portions c and d side than on its side facing the edge. Also these not pictured

Cylindrical lenses in sections a and b of the second lens array 10 correspond in size and shape to form a third group of like lenses. Again, the unillustrated cylindrical lenses of the third group in sections a and b of the second lens array 10 are different from the cylindrical lenses 13 of the first group in sections c and d and different from the cylindrical lenses 13 of the second group in sections e and f. If, as mentioned in the direction of the arrows 4 left and right further cylindrical lenses 13 connect, these are also in groups of the same but to the

Cylindrical lenses of other groups combined different cylindrical lenses. The change in the symmetry or asymmetry of the cylindrical lenses takes place only during the transition from one group to the next, that is to say, for example, during the transition from section b to section c or during the transition from section d to section e. By this same design of the cylindrical lenses in the individual groups of manufacturing costs can be reduced.

The light beams which are deflected by the device 5 and which are superposed on the working plane 8 with respect to the X direction, can be viewed in the Y direction by focusing means (not shown) be focused so that in the working plane 8 is formed in the X direction extending line-shaped intensity distribution. This intensity distribution can be very little extended in the Y direction and be very wide in the X direction, for example more than 50 cm wide, and can also be very homogeneous in the X direction.

FIG. 5 a shows an intensity distribution corresponding to FIG. 1 b of a device for producing a linear intensity distribution in a working plane which has more light sources in the Y direction than the device according to FIG. 1 a. Then, after compression in the Y direction, significantly more light beams 3 result in the Y direction next to each other or in FIG. 5a through the first beam shaping means.

The rotation through the second beam-shaping means then results in several rows 14 of light beams which are arranged close to one another in the X-direction being arranged side by side or one below the other in the Y-direction (see FIG. 5b). These different rows 14 of light beams can be merged by unillustrated beam shaping means and / or focusing means in the working plane 8 in the Y direction to a linear intensity distribution which extends like the already described linear intensity distribution in the X direction.

Claims

claims:

1 . Apparatus for homogenizing light, comprising

a first lens array (9) having a plurality of lenses juxtaposed in a first direction (X) and having at least a first pitch (Pi), the light to be homogenized passing through the first lens array (9);

a second lens array (10) having a plurality of lenses arranged side by side in the first direction (X) and having at least a second center distance (P ₂ ), wherein the second lens array (10) in the propagation direction (Z) of the light to be homogenized disposed behind the first lens array (9) so that light passed through the first lens array (9) can pass through the second lens array (10);

characterized in that the at least one second center distance (P ₂ ) of the second lens array (10) is different from the at least one first center distance (P ₁ ) of the first lens array (9), so that through different lenses of the second lens array (10) therethrough have passed portions of the light to be homogenized in the propagation direction (Z) of the light behind and spaced from the second lens array (10) in the first direction (X) are superposed with each other.

2. Device according to claim 1, characterized in that the at least one second center distance (P ₂ ) of the second Lens arrays (10) is smaller than the at least a first center distance (Pi) of the first lens array (9).

3. Device according to claim 2, characterized in that the at least one second center distance (P2) of the second lens array (10) differs by less than 10 μm from the at least one first center distance (Pi) of the first lens array (9).

4. Apparatus according to claim 3, characterized in that the at least one second center distance (P2) of the second lens array (10) to less than 5 microns, in particular to

0, 1 .mu.m to 3 .mu.m, preferably by 0.5 .mu.m to 1, 5 .mu.m, for example, differs by about 1 micron from the at least one first center distance (P-i) of the first lens array (9).

5. Device according to one of claims 1 to 4, characterized in that the lenses of the first lens arrays (9) and / or the lenses of the second lens array (10) cylindrical lenses (1 1, 12, 13).

6. The device according to claim 5, characterized in that the cylinder axes of the cylindrical lenses (1 1) of the first lens array (9) and / or the cylindrical lenses (12, 13) of the second lens array (10) in a direction to the first direction (X ) extend perpendicular second direction (Y), which is in particular perpendicular to the propagation direction (Z) of the light to be homogenized.

7. Device according to one of claims 1 to 6, characterized in that the lenses of the first lens array (9) are identical to each other.

8. Device according to one of claims 1 to 7, characterized in that at least some of the lenses of the second lens array (10) are different from each other.

9. Device according to one of claims 1 to 8, characterized in that at least in the edge regions of the second lens array (10) arranged lenses are asymmetrical, in particular with respect to a central Y-Z plane.

10. A device for generating a linear intensity distribution in a working plane, comprising

- At least one light source (1);

a device (5) for homogenizing the light emitted by the light source (1);

Focusing means for focusing the light in a working plane (8);

characterized in that the device for

Homogenization is a device (5) according to one of claims 1 to 9.

1 1. A device according to claim 10, characterized in that the device comprises a plurality of light sources (1).

12. Device according to one of claims 10 or 11, characterized in that the device comprises beam shaping means, of which the light of the at least one light source (1) can be shaped such that before or in the device (5) for homogenization a plurality in the first direction (X) juxtaposed local intensity maxima of the light arise.