Device for scanning an eye

Abstract

The invention relates to a device for scanning an eye (1), comprising a scanning device (2) with a reflective surface (3) onto which at least one incident light beam (4a, 4b) can be deflected. A light beam (5a, 5b) which is reflected towards the incident light beam (4a, 4b) by the reflective surface (3) can be pivoted over an angular range (6a, 6b) by means of the scanning device (2). The aim of the invention is to provide a device for scanning an eye or a part of an eye, said device having a scanning angle which can be adjusted as variably as possible and being used to generate images with the highest possible quality at the fastest possible speed. The invention is characterized in that means are provided which can be used to deflect at least two mutually spaced incident light beams (4a, 4b) onto the reflective surface (3) such that at least two reflected light beams (5a, 5b) can be pivoted over an angular range (6a, 6b).

Description

[0001] Device for scanning an eye

[0002] The invention relates to a device according to the preamble of claim 1.

[0003] A device for scanning an eye usually comprises a scanning device with a reflection surface onto which an incident light beam can be directed, wherein a light beam reflected from the reflection surface onto the incident light beam can be pivoted by means of the scanning device over an angular range, the so-called scanning angle.

[0004] Against this background, confocal laser scanning devices have become known, which are limited in terms of light intensity and speed due to the use of only one light beam.

[0005] This limitation is due to the fact that the technical parameters of scanning speed, scanning angle, and scanning area are somewhat interdependent and cannot be increased indefinitely. Scanners with large scanning areas and scanning angles are often relatively slow.

[0006] Conversely, scanners with small scanning areas and small scanning angles can often be operated very quickly.

[0007] The product of the scanning area and the scanning angle determines the light intensity and often cannot be significantly increased even through optical translation. This can limit the light intensity or speed, especially in a wide-angle system.

[0008] Scanners with small scanning angles require long focal lengths to produce large intermediate images. This also increases the space required for the optics used. Devices that are confocal in only one axis exhibit lower image quality. Therefore, relatively complex optics and very sensitive line scan cameras are required.

[0009] Against this background, there is a need for devices for scanning wide angles in front of the eye that are fast, light-sensitive, and offer very good image quality. These devices should be as compact as possible. Furthermore, there is a need for very fast scanning devices that produce smaller scanning angles.

[0010] The invention is therefore based on the object of providing a device for scanning an eye or a part of an eye, which device has a scanning angle that can be adjusted as variably as possible and by means of which images of the highest possible quality can be generated at the highest possible speed.

[0011] The present invention solves the aforementioned problem by the features of claim 1. First, it has been recognized that there is a need for devices for scanning wide angles, particularly ± 50° in front of the eye, that are fast and have high light sensitivity and very good image quality. These devices should be as compact as possible.

[0012] It has also been recognized that there is a need for very fast scanning devices that produce smaller scanning angles.

[0013] It has further been recognized that a device which meets these needs must have means by which at least two spaced-apart, incident light beams can be directed onto a reflection surface, so that at least two reflected light beams can each be pivoted over an angular range.

[0014] This multi-beam approach allows an increase in the primary scanning angle without the disadvantages described above.

[0015] Ideally, if there are no overlaps or gaps, the total angular range, i.e., the total scanning angle, increases by a factor of the "number of light beams." The general formula is: total scanning angle equals the scanning angle of the scanning device times the number of light beams.

[0016] It has therefore been recognized that with multiple light beams the total scanning angle can be increased at a constant speed or the speed at a constant total scanning angle.

[0017] The incident light beams could be aligned parallel to each other in front of the scanning unit, but spaced apart from each other. This allows the beams to be guided together through a lens and also refracted together onto the reflective surface. A first light beam reflected by the reflective surface could cover a first angular range, while a second light beam reflected by the reflective surface simultaneously covers a second angular range, so that a total angular range can be scanned or detected. By using multiple light beams, preferably two or more light beams, the total angular range is increased approximately proportionally to the number of incident or reflected light beams.

[0018] The angular ranges of the individual light beams could overlap. A slight overlap can be used for image processing, particularly for spatially matching sub-images, but also for adjusting intensities.

[0019] A separate detector could be provided for each incident, returning, and / or reflected light beam. This allows light beams with different wavelengths and / or different interference patterns to be detected independently of one another in conjunction with a reference light beam.

[0020] A primary light beam emitted by a light source could pass through one or more beam splitters as an incident light beam onto the reflective surface and from there reach the eye as a reflected light beam. A light beam returning from the eye along the same optical path is guided at this beam splitter into a detector beam directed to a corresponding detector. The light beam returning from the eye or the object to be examined can thus interfere with a light beam from a reference arm and be combined with this light beam from the reference arm to form a detector beam. The detector beam can then be detected by the detector and evaluated by a downstream device.

[0021] The means could comprise an optical device for splitting light, by which a single light beam can be split into two or more light beams incident on the reflecting surface and / or into two or more primary light beams incident on a beam splitter. Thus, only one light source can be used. The light beam from this light source is then split or multiplied using optical methods. In this case, the use of beam splitters or prisms would be possible, for example; however, multiple sub-beams could also be generated from a large primary laser beam by diaphragms. In this context, Hartmann-Shack lenslets, for example, are conceivable.

[0022] The means could comprise different and / or independent light sources, each emitting a primary light beam or an incident light beam. Thus, light of different wavelengths can be used to scan an object.

[0023] Two or more light beams could intersect on the reflective or mirror surface of the scanning device. In this case, several light beams could be detected or scanned in parallel.

[0024] This can be done in the X-direction, i.e., along the fast scan axis, or in the Y-direction, i.e., along the slow scan axis, or in both directions. This increases the overall scan angle of the device. By increasing the scan amplitude at the same speed and scan area, the product of the scan area and scan angle of the scanning device can be increased.

[0025] This advantage can be used in several ways:

[0026] Significantly higher scanning speeds are achievable. Significantly higher light intensities are achievable, resulting in better resolution and fewer artifacts caused by lens flare. There is greater flexibility in the selection of scanning devices. Due to only slight magnification of the scanning device, more compact designs and / or longer working distances are possible.

[0027] In the drawing, the only

[0028] Fig. in schematic and partial view a device for scanning an eye, in particular a human eye, in which several light beams simultaneously impinge on a reflection surface of a scanning device in order to be directed to the eye.

[0029] The single figure shows a device for scanning an eye 1, namely a human eye 1, comprising a scanning device 2 with a reflection surface 3, onto which at least one incident light beam 4a, 4b can be directed, wherein a light beam 5a, 5b reflected from the reflection surface 3 onto the incident light beam 4a, 4b is

[0030] 2 can be pivoted over an angular range 6a, 6b.

[0031] Several light beams 4a, 4b, here specifically two light beams 4a, 4b, are directed onto the same scanning device 2 and can be reflected on the reflection surface

[0032] 3 intersect. The light beams 4a, 4b can be scanned in parallel. To generate multiple light beams 4a, 4b, either multiple light sources 8a, 8b can be used, as shown, or a single primary light beam from a light source could be split or multiplied using optical beam splitters.

[0033] Specifically, however, it is shown that two light sources 8a, 8b are provided as means by which two spaced-apart, incident light beams 4a, 4b can be directed onto the reflection surface 3, so that at least two reflected light beams 5a, 5b can each be pivoted over an angular range 6a, 6b.

[0034] The means specifically comprise different and independent light sources 8a, 8b, each of which emits a primary light beam 9a, 9b, which passes through a beam splitter 11h and falls as incident light beam 4a, 4b onto a lens 12.

[0035] The incident light rays 4a, 4b are aligned parallel but spaced apart from each other and pass through the lens 12 to then be directed onto the reflection surface 3 of the scanning device 2 and to be incident thereon.

[0036] The angle between the light beams 4a, 4b, especially after passing through the lens 12, is preferably adapted to the scanning angle of the scanning device 2. The light beams 4a, 4b could intersect on the reflection surface 3.

[0037] A first light beam 5a reflected by the reflection surface 3 covers a first angular range 6a, while a second light beam 5b reflected by the reflection surface 3 simultaneously covers a second angular range 6b, so that a total angular range 6c is scannable or detectable. The angular ranges 6a, 6b could overlap. The reflected light beams 5a, 5b are guided to the eye 1, and from the eye 1, returning light beams 4'a, 4'b travel back along the same optical path. This is represented by the back-and-forth arrows in the drawing.

[0038] A separate detector 7a, 7b is provided for each incident, returning, and / or reflected light beam 4a, 4b, 4'a, 4'b, 5a, 5b. Each light beam requires a separate detector 7a, 7b.

[0039] Specifically, it is shown that a primary light beam 9a, 9b emitted by a light source 8a, 8b passes through a beam splitter 11 as a light beam 4a, 4b incident on the reflection surface 3 and initially falls on an eye 1 as a reflected light beam 5a, 5b.

[0040] A light beam 4'a, 4'b returning from the eye 1 along the same optical path is converted at the beam splitter 11 into a detector beam 10a, 10b, which is directed to a detector 7a, 7b assigned to it.

[0041] The returning light beam 4'a, 4'b undergoes a combination and interference in the detector beam 10a, 10b with a light beam (not shown) from a reference arm.

[0042] List of reference symbols:

[0043] 1 eye

[0044] 2 Scanning device

[0045] 3 Reflection surface of 2

[0046] 4a, 4b on 2 incident light beam

[0047] 4'a, 4'b of 2 returning light beams

[0048] 5a, 5b light beam reflected from 2, 3

[0049] 6a angle range, scan angle of 4a, 5a

[0050] 6b angle range, scan angle of 4b, 5b

[0051] 6c Total angle range, total scan angle

[0052] 7a, 7b Detector

[0053] 8a, 8b Light source for 9a, 9b

[0054] 9a, 9b primary light beam

[0055] 10a, 10b detector beam

[0056] 11 beam splitters

[0057] 12 lenses

[0058] 13 Investigation level

[0059] 14 Light spot

Claims

Claims: Device for scanning an eye (1), comprising a scanning device (2) with a reflective surface (3) onto which at least one incident light ray (4a, 4b) can be directed, wherein a light ray (5a, 5b) reflected from the reflective surface (3) onto the incident light ray (4a, 4b) can be pivoted by means of the scanning device (2) over an angular range (6a, 6b), characterized in that means are provided by which at least two spaced-apart incident light rays (4a, 4b) can be directed onto the reflective surface (3) so that at least two reflected light rays (5a, 5b) can each be pivoted over an angular range (6a, 6b). Device according to claim 1, characterized in that the incident light rays (4a, 4b) are aligned parallel but spaced apart from each other.Device according to claim 1 or 2, characterized in that a first reflected light ray (5a) sweeps over a first angular region (6a), while a second reflected light ray (5b) simultaneously sweeps over a second angular region (6b), such that a total angular region (6c) is scannable or detectable. Device according to any one of claims 1 to 3, characterized in that the angular regions (6a, 6b) overlap. Device according to any one of the preceding claims, characterized in that for each incident, reflected, and / or... Each reflected light beam (4a, 4b, 4'a, 4'b, 5a, 5b) is provided with its own detector (7a, 7b). Device according to one of the preceding claims, characterized in that a primary light beam (9a, 9b) emitted from a light source (8a, 8b) passes through one or more beam splitters (11) as a light beam (4a, 4b) incident on the reflective surface (3) and that a reflected light beam (4'a, 4'b) is directed at this beam splitter (11) into a detector beam (10a, 10b) which is directed towards an associated detector (7a, 7b). Device according to one of the preceding claims, characterized in that the means comprise an optical device for splitting light, by which a single light beam can be split into two or more light beams (4a, 4b) incident on the reflecting surface (3) and / or into two or more primary light beams (4a, 4b, 9a, 9b) incident on a beam splitter (11).Device according to one of the preceding claims, characterized in that the means comprise different and / or independent light sources (8a, 8b), each of which emits a primary light ray (9a, 9b) or an incident light ray (4a, 4b).

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