Apparatus having a scanning device
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- HEIDELBERG ENGINEERING GMBH
- Filing Date
- 2024-05-16
- Publication Date
- 2026-05-13
AI Technical Summary
Conventional confocal laser scanning systems are limited by their light intensity and speed due to the interdependence of scanning speed, angle, and area, which restricts the product of scanning area and angle, and require complex optics and sensitive detectors for wide-angle systems, leading to higher costs and reduced image quality.
The system increases the overall scanning angle by using optical means to pivot the reflected light beam over a second angular range, allowing the light beam to pass over the same scanning surface multiple times, thereby multiplying the product of scanning area and angle, and utilizing a compact design with a single detector for enhanced light intensity and speed.
This approach enables the creation of wide-angle scanning systems with improved image quality and increased scanning speed, reducing the space required for optics and eliminating the need for multiple detectors, resulting in higher light intensity and faster scanning without sacrificing image resolution.
Smart Images
Figure EP2024063502_09012025_PF_FP_ABST
Abstract
Description
[0001] Device with a scanning device
[0002] The invention relates to a device according to the preamble of claim 1.
[0003] A device for scanning an eye typically comprises a scanning device with a scanning surface or reflection surface onto which an incident light beam can be directed. A light beam reflected from the reflection surface toward the incident light beam can be pivoted by the scanning device over an angular range, the so-called scan angle. This allows structures to be examined by scanning with light beams.
[0004] Against this background, confocal laser scanning systems with a single beam and a point detector are already known. Laser scanning systems with line illumination and line detection are also known.
[0005] Conventional confocal laser scanning systems are limited in terms of light intensity and speed. This is because the properties of scanning speed, scanning angle, and scanning area are somewhat interdependent and cannot be increased indefinitely.
[0006] Scanning systems with large scanning areas and angles are often relatively slow. Conversely, small scanning systems with small scanning angles are often very fast. The product of the scanning area or reflection area and the scanning angle determines the light intensity and cannot be increased even by optical translation. This can limit the light intensity or speed, especially for wide-angle systems. Scanning systems with small scanning angles use long focal lengths to create large intermediate images. This increases the space required for the optics.
[0007] Laser scanning systems with line illumination and line detection are confocal in only one axis. This results in lower image quality and relatively complex optics, requiring very sensitive line scan cameras. When multiple detectors and light sources are used, or when beam expansion is used, additional optics are required, which entails higher costs.
[0008] The invention is therefore based on the object of specifying a device with a scanning device with which a large overall scanning angle can be realized as easily as possible, in particular without reducing the scanning area or the speed.
[0009] The present invention solves the above-mentioned problem by the features of claim 1.
[0010] First, it was inventively recognized that there is a need for wide-angle scanning systems, especially in front of the eye ± 30° and larger, that are fast and offer excellent image quality. It was also recognized that these wide-angle scanning systems should be as compact as possible to ensure operational usability. Furthermore, it was recognized that there is a need for fast scanning systems with smaller scanning angles.
[0011] According to the invention, it has been recognized that a device for examining an object or for scanning an eye must comprise at least one scanning device with a reflection surface onto which at least one light beam emitted by a light source can be directed, wherein a reflected light beam extending from the reflection surface towards the incident light beam can be pivoted over a first angular range by means of the scanning device.
[0012] Inventively, optical means are provided by which the outgoing reflected light beam, after passing through the means, can be pivoted over a second angular range, wherein the second angular range is larger than the first angular range. This allows a light beam, in particular a laser beam, to pass over the same scanning surface or reflection surface of the scanning device multiple times, but from different angles, as in a loop, so that the overall scanning angle is increased.
[0013] The light beam is redirected via beam-guiding components and re-imaged onto the same scanning surface or reflection surface, or the scanning device is essentially optically imaged onto itself. The scanning angle is increased, preferably doubled, while the scanning area remains the same. This multiplies the area times angle, allowing for systems with greater light intensity or speed.
[0014] The device described here allows for more flexible scanner selection. A larger scanning angle allows for closer to a 1:1 image for wide-angle systems, which is an advantage due to optical symmetry in the creation of certain optical aberrations. A low optical translation ratio leads to shorter focal lengths, which in turn has a positive effect on space requirements.
[0015] The second angular range could be twice as large as the first. This effectively increases the overall scanning angle and optimizes its magnification.
[0016] The reflected light beam emanating from the reflective surface could be guided back to the reflective surface by the optical means and from there pivoted across the second angular range as a returned light beam. The light beam pivoted across the second angular range is then a twice-scanned light beam. The scanning device or its scanning surface is thus essentially redirected via optical components and imaged back onto itself. The light to be scanned or captured passes over the scanning device multiple times, preferably over the same spot or surface, and is thus scanned multiple times. This increases the overall scan angle of the scanning system, while the beam diameter of the light beam does not change and its luminous intensity is therefore essentially maintained. In concrete terms, the beam diameter remains the same and the luminous intensity is increased because the scanning angle is increased.The product of scan angle and scan area is thus increased by the use of optical deflection devices.
[0017] The incident light beam from the light source, essentially a stationary light beam, could be directed onto the reflection surface at a different angle than the returned light beam. By selecting the different angle, the size of the overall scanning angle can be adjusted.
[0018] The reflected light beam emanating from the reflective surface could, after passing through the optical means and re-entering the reflective surface, be directed from the latter to an optical device or an object under examination for scanning. The optical device or the object under examination could thus be penetrated by light beams that form a large overall scanning angle. An object under examination could be examined through a type of wide-angle lens.
[0019] A detector or a single detector could be provided that detects a light beam returning from the optical device or the object under investigation, or a signal from the returning light beam. Using only one detector, the device can be compact. The returning light beam can be scattered and / or reflected by the object under investigation.
[0020] The light beam returning from an object under investigation could be directed to the reflecting surface, from there through the optical means, and from there back to the reflecting surface, from which it is guided to the detector. This allows the object under investigation to be scanned with high light intensity.
[0021] A stationary light beam emerging from the light source and a light beam returning to the detector could be guided parallel and / or collinear. This allows for a compact device design and eliminates the need for deflection devices. Furthermore, the outgoing light beam and the returning light beam can be relatively easily interfered, potentially enabling OCT images to be captured.
[0022] The optical means could include at least two deflecting mirrors. These mirrors allow light beams to be deflected reliably around corners, ideally without loss of intensity. By appropriately arranging and spacing the deflecting mirrors relative to each other, the overall scanning angle can be easily adjusted.
[0023] The optical means could comprise at least two lenses or four lenses. Two lenses can be arranged confocally relative to each other, thus enabling a confocal design of the device.
[0024] The optical means could include at least one curved mirror. Such a mirror can both redirect light and focus it at a focal point.
[0025] The scanning device could comprise an X-scanning device or be designed as such, with a Y-scanning device also being provided. This makes it possible to scan an object flatly, i.e., laterally. A two-dimensional representation of the object under investigation can be created.
[0026] The Y-scanning device could be designed as a deflecting mirror, through which the outgoing reflected light beam, after being reflected by two preceding deflecting mirrors, can be redirected back to the reflecting surface as a returned light beam. From there, it can be guided to an optical device or an object to be examined, which can be scanned in the Y-direction. This configuration allows both scanning devices to be used simultaneously, and the object can be scanned in the X- and Y-directions simultaneously. In particular, this configuration maps the X- and Y-scanners or scanning devices to one another, resulting in an ideal scanning pupil.
[0027] Light incident on the Y-scanning device could be guided through a third lens before striking the Y-scanning device, and light exiting the Y-scanning device could be guided through a fourth lens. This allows the third lens to be arranged confocally with a first lens, and the fourth lens to be arranged confocally with a second lens.
[0028] Against this background, at least two lenses could be arranged confocally to each other and / or with the interposition of one or two deflecting mirrors. By using deflecting mirrors, the confocally arranged lenses can be arranged particularly compactly relative to each other. The coincident focal points of two lenses used can easily be located next to or on a deflecting mirror.
[0029] The device described here makes it possible to adjust a scan angle via a 4f image of a scan surface onto itself. An additional scan axis, which can be realized using a Y-scanning device, can be integrated into the device and mapped onto the X-scanning device. This achieves an optimal scan pupil for the entire scanning system without optical offset. A compact intermediate image can be used for position feedback. This can potentially simplify a main optics or an optical device. Furthermore, the device described here improves image quality through higher light intensity.
[0030] With the device described here, it is possible to achieve four times the amount of light emerging from an examined eye, thus enabling a double scan. It has a better numerical aperture and better optical resolution. Fewer lens flares occur due to a larger possible beam diameter. The device described here requires only one detector. Merging multiple individual images is not necessary. Overlapping of individual images is not required. A shorter integration time at the detector is possible with the same resolution. Multiple optical components can be placed in one beam path. The scanning angle is magnified through multiple scanning.
[0031] In the drawing show
[0032] Fig. 1 is a schematic representation of the functional structure of a device with static or non-deflected scanning device,
[0033] Fig. 2 shows the functional structure according to Fig. 1 , wherein a scanner deflection is shown schematically to represent the total scanning angle,
[0034] Fig. 3 shows a functional structure of another device in which an additional Y-scan axis is realized, with static scanning device, and
[0035] Fig. 4 shows the functional structure according to Fig. 3 with an additional Y-scan axis, whereby a scanner deflection is shown schematically to represent the total scan angle.
[0036] 1 and 2 schematically show a device 10 for examining an object or for scanning an eye 1, comprising a scanning device 2 with a reflection surface 3, onto which at least one light beam 4 emitted by a light source 8 can be directed, wherein a reflected light beam 5a running from the reflection surface 3 towards the incident light beam 4 can be pivoted by means of the scanning device 2 over a first angular range 6a when the reflection surface 3 is deflected.
[0037] The incident light beam 4 is reflected and pivoted as an outgoing reflected light beam 5a over the first angular range 6a. This is illustrated in Fig. 2 using a schematically represented scanner deflection. The outgoing reflected light beam 5a is represented by a solid white line. The outgoing reflected light beam 5a is thus a simply scanned light beam. Optical means are provided by means of which the outgoing reflected light beam 5a, after passing through the means, can be pivoted over a second angular range 6c, which is larger than the first angular range 6a. Specifically, the second angular range 6c is twice as large as the first angular range 6a and represents the total scanning angle of the device. This is also illustrated in Fig. 2.
[0038] The light beam 5a pivoted over the second angular range 6c is in this respect a twice-scanned light beam because it is first reflected by the reflection surface 3 and guided to the optical means, then returned to the same location on the reflection surface 3 and then pivoted from there to an optical device 15, in particular a main optics, or to an object to be examined over the second angular range 6c, namely the total scan angle.
[0039] Fig. 2 specifically shows how the first angular range 6a can be converted into the second angular range 6c upon deflection of the reflection surface 3 of the scanning device 2. Light rays 5a, which strike and exit the reflection surface 3 at different angles, are schematically depicted with different ends. The ends comprise a rhombus, a circle, and an arrowhead.
[0040] Each reflected light beam 5a emanating from the reflection surface 3 toward the optical means can be redirected by the optical means to the reflection surface 3 as a redirected light beam 5a and from there pivoted across the second angular range 6c. This is illustrated by the fact that each redirected light beam 5a is also represented by a solid white line.
[0041] The outgoing reflected light beam and returned light beam 5a is initially a single-scanned light beam and is then converted into a double-scanned light beam 5a when it is pivoted across the second angular range 6c. A light beam 4 incident on the reflection surface 3, which can also be referred to as a stationary light beam, can be guided to the reflection surface 3 at a different angle than a returned light beam 5a. The reflected light beam 5a exiting from the reflection surface 3 is guided in a loop, so to speak, and initially leaves the reflection surface 3, before passing through the optical means and re-imposing it, from where it is guided to an optical device 15 or an object to be examined.
[0042] The reflected light beam 5a emerging from the reflection surface 3 is guided, after passing through the optical means, from the reflection surface 3 to an optical device 15 or an object to be examined in order to scan it.
[0043] Specifically, only one detector 7 is provided, which detects a light beam 5b returning from the optical device 15 or the object to be examined, or a signal from the returning light beam 5b. The returning light beam 5b is a light beam backscattered or reflected by the object to be examined.
[0044] Light rays returning from the optical device 15 or the object to be examined are represented by dashed white lines.
[0045] Returning light rays 5b, which strike and leave the reflection surface 3 at different angles, are schematically shown with different ends, the ends comprising a rhombus, a circle and an arrowhead.
[0046] Each returning light beam 5b can be guided onto the reflection surface 3, from there through the optical means and from there back onto the reflection surface 3 in order to be guided from there to the detector 7.
[0047] Thus, a light beam 4 emanating from the light source 8 can be caused to interfere with a returning light beam 5b, particularly when a reference arm is present for examining structures. Light beams 4 emanating from the light source 8 and light beams 5b returned to the detector 7 can be guided parallel and / or collinearly. Figs. 1 and 2 show that the optical means comprise at least two deflecting mirrors 16a, 16b. A reflected light beam 5a emanating from the reflecting surface 3 toward the optical means is deflected by the deflecting mirrors 16a, 16b via two angles or corners and redirected to the reflecting surface 3 as a returned light beam 5a.
[0048] The optical means further comprise two lenses 12a, 12b, which are arranged confocally such that their focal points lie between the deflection mirrors 16a, 16b and one above the other. This gives the device a confocal design. Specifically, a first lens 12a and a second lens 12b—namely, only two lenses—are provided.
[0049] 3 and 4 show a further device 10' for examining an object or for scanning an eye 1, comprising a scanning device 2 with an X-scanning device 2a with a reflection surface 3, onto which at least one light beam 4 emitted by a light source 8 (not shown) can be directed, wherein a reflected light beam 5a running from the reflection surface 3 towards the incident light beam 4 can be pivoted by means of the scanning device 2, 2a over a first angular range 6a.
[0050] An outgoing reflected light beam 5a is shown in analogy to Fig. 2 with a solid white line.
[0051] Optical means are provided by means of which the outgoing reflected light beam 5a, after passing through the means, can be pivoted over a second angular range 6c which is larger than the first angular range 6a.
[0052] Specifically, the second angular range 6c is twice as large as the first angular range 6a and represents the total scanning angle of the device.
[0053] The reflected light beam 5a, which extends from the reflection surface 3 toward the optical means, can be redirected by the optical means as a redirected light beam 5a to the reflection surface 3 and from there pivoted across the second angular range 6c. This is illustrated by the fact that the redirected light beam 5a is also represented by a solid white line.
[0054] A light beam 4 incident on the reflection surface 3 can be guided to the reflection surface 3 at a different angle than a returned light beam 5a. The light beam 5a is guided in a loop, so to speak, and initially leaves the reflection surface 3, before passing through the optical means and being guided from there to an optical device 15 or an object to be examined.
[0055] The reflected light beam 5a emerging from the reflection surface 3 is guided, after passing through the optical means, from the reflection surface 3 as a returned light beam 5a onto an optical device 15 or an object to be examined in order to scan it.
[0056] Specifically, only one detector 7 (not shown) is provided, which detects a light beam 5b returning from the optical device 15 or the object to be examined or a signal of the returning light beam 5b.
[0057] Light rays 5b returning from the optical device 15 or the object under investigation are represented by dashed white lines. Each returning light ray 5b can be guided to the reflection surface 3, from there through the optical means, and from there back to the reflection surface 3, from which it can be guided to the detector 7.
[0058] Thus, a light beam 4 emanating from the light source 8, which can also be referred to as a stationary light beam, can be caused to interfere with a returning light beam 5b, in particular to examine structures. A light beam 4 emanating from the light source 8 and a light beam 5b returning to the detector 7 can be guided parallel and / or collinear.
[0059] Figs. 3 and 4 show that the optical means comprise two deflecting mirrors 16a, 16b, which deflect the outgoing reflected light beam 5a and the returning light beam 5b, respectively, through two angles or corners. The reflected light beam 5a, which exits from the reflection surface 3 toward the optical means, is deflected by a first deflecting mirror 16a through a first lens 12a to a second deflecting mirror 16b. From the second deflecting mirror 16b, the outgoing reflected light beam 5a is guided through a further, third lens 12c.
[0060] The first lens 12a and the further, third lens 12c are arranged confocally such that their focal points lie slightly next to or on top of the second deflection mirror 16b.
[0061] The outgoing reflected light beam 5a is directed by the further, third lens 12c onto a Y-scanning device 2b, which is assigned to the scanning device 2 and / or electronically connected to it for simultaneous control. The scanning device 2 therefore comprises an X-scanning device 2a and, in addition, the Y-scanning device 2b. The X-scanning device 2a operates faster than the Y-scanning device 2b.
[0062] The Y-scanning device 2b is designed as a deflecting mirror, by means of which the outgoing reflected light beam 5a, after reflection at the two preceding deflecting mirrors 16a, 16b, can be returned to the reflection surface 3 in order to be guided from there to the optical device 15 or the object to be examined in order to also scan it in the Y-direction.
[0063] Both the outgoing reflected light beam 5a and the returning light beam 5b are therefore each deflected over three angles or corners.
[0064] From the Y-scanning device 2b, the outgoing reflected light beam 5a is redirected to the reflection surface 3 as a returned light beam 5a after first passing through a fourth lens 12d and then through a second lens 12b.
[0065] The second lens 12b and the fourth lens 12d are confocally arranged such that their focal points lie between them. The returned light beam 5a is then guided by the X-scanning device 2a to the optical device 15 or the object to be examined.
[0066] Fig. 4 shows, in analogy to Fig. 2, the scanner deflection of the scanning device 2.
[0067] In Figs. 3 and 4, the basic structure of the device according to Figs. 1 and 2 is expanded to include an additional scanning mirror, namely the Y-scanning device 2b. The Y-scanning device 2b is imaged onto the X-scanning device 2a via a 4f image, resulting in an optimal scanning pupil without optical offset. In addition, a complete, compact XY intermediate image is available, which can be used for position feedback.
[0068] Fig. 2 and Fig. 4 each show the functional structure of the devices using schematically illustrated scanner deflections.
[0069] The image does not necessarily have to be created using optical lenses, as shown here. Alternatively, other optical components could be used, such as curved mirrors.
[0070] The principle of the devices described here is as follows:
[0071] A light beam 4 strikes a scanning device 2 and is variably deflected, or scanned, by it. Using a 4f image comprising two lenses 12a, 12b and two deflecting mirrors 16a, 16b, the scan surface or the reflected surface of the scanning device 2 is imaged onto itself.
[0072] Due to the deflecting mirrors 16a, 16b, the returning, redirected light beam 5a hits the scanning device 2 at a different angle than the outgoing reflected light beam 5a. The light beam 5a thus passes over the same scanning area twice, doubling the total scanning angle 6c.
[0073] The ability to increase the total scan angle 6c in this way while maintaining the same light beam diameter offers several advantages. The gain, namely the product of angle times area, can be used to create faster systems with higher scan rates or higher light yield.
[0074] This is illustrated by the following further examples, which are intended to illustrate the effect of the invention described here using existing products:
[0075] Example 1 : Improvement of light intensity / image quality
[0076] CRS 4 kHz, 10 mm scan area, + / - 10 degrees optical scan angle
[0077] 60°, 4 kHz scan system
[0078] Conventional scanner Dual scanner
[0079] Frequency X Scanner [kHz] 4 4
[0080] Scanning area diameter [mm] 9 9
[0081] Total scan angle optical [degrees] 20 40
[0082] Target angle on the lens [degrees] 60 60
[0083] Optical translation 3 1 ,5
[0084] Pupil of the eye diameter 3 6
[0085] Example 2: Increasing scan speed:
[0086] 30°, 12 kHz scan system
[0087] Conventional scanner Dual scanner
[0088] Frequency X Scanner [kHz] 8 12
[0089] Scanning area diameter [mm] 5 5
[0090] Total scan angle optical [degrees] 20 20 (2x10°)
[0091] Target angle on the lens [degrees] 30 30
[0092] Optical translation 1 .5 1 .5
[0093] Pupil of the eye diameter 3.33 3.33
[0094] The technology described here can be used in a wide-angle system. The resulting high light intensity leads to improved image quality. Alternatively, an increased scanning speed is also possible. The aforementioned technical features are important prerequisites for the operational suitability of a device. List of reference symbols:
[0095] 1 eye or object to be examined
[0096] 2 Scanning device
[0097] 2a X-scanning device of 2
[0098] 2b Y-scan device of 2
[0099] 3 Reflection surface of 2, 2a
[0100] 4 to 3 incident light beam from 8
[0101] 5a light beam outgoing from 3 and returning to 3
[0102] 5a of 3 over 6c tilted light beam
[0103] 5b of 1 returning light beam
[0104] 6a first angular range of 5a
[0105] 6c second angular range of 5a
[0106] 7 Detector
[0107] 8 Light source
[0108] 10, 10' device
[0109] 12a-12d first to fourth lenses
[0110] 15 optical device or main optics
[0111] 16a first deflecting mirror
[0112] 16b second deflection mirror
Claims
Patent claims 1. Device (10, 10') for examining an object or for scanning an eye (1), comprising a scanning device (2, 2a) with a reflection surface (3) onto which at least one light beam (4) emitted by a light source (8) can be directed, wherein a reflected light beam (5a) emerging from the reflection surface (3) towards the incident light beam (4) can be pivoted by means of the scanning device (2) over a first angular range (6a), characterized in that optical means are provided by means of which the emerging reflected light beam (5a), after passing through the means, can be pivoted over a second angular range (6c) which is greater than the first angular range (6a).
2. Device according to claim 1, characterized in that the second angular range (6c) is twice as large as the first angular range (6a).
3. Device according to claim 1 or 2, characterized in that the reflected light beam (5a) emerging from the reflection surface (3) can be returned by the optical means to the reflection surface (3) and from there can be pivoted over the second angular range (6c).
4. Device according to claim 3, characterized in that the incident light beam (4) can be guided onto the reflection surface (3) at a different angle than the returned light beam (5a).
5. Device according to one of claims 1 to 4, characterized in that the outgoing reflected light beam (5a), after passing through the optical means, can be guided from the reflection surface (3) to an optical device (15) or an object to be examined in order to scan it.
6. Device according to claim 5, characterized in that a detector (7) or only one detector (7) is provided which detects a light beam (5b) returning from the optical device (15) or the object to be examined or a signal of the returning light beam (5b).
7. Device according to claim 6, characterized in that the returning light beam (5b) can be guided onto the reflection surface (3), from there through the optical means and from there again onto the reflection surface (3) in order to be guided from there to the detector (7).
8. Device according to claim 7, characterized in that the outgoing light beam (4) and the light beam (5b) returning to the detector (7) can be guided parallel and / or collinear.
9. Device according to one of the preceding claims, characterized in that the optical means comprise at least two deflecting mirrors (16a, 16b).
10. Device according to one of the preceding claims, characterized in that the optical means comprise at least two lenses (12a, 12b) or four lenses (12a, 12b, 12c, 12d).
11. Device according to one of the preceding claims, characterized in that the optical means comprise at least one curved mirror.
12. Device (10') according to one of the preceding claims, characterized in that the scanning device (2) comprises an X-scanning device (2a) or is designed as such, wherein a Y-scanning device (2b) is additionally provided.
13. Device according to claim 12, characterized in that the Y-scanning device (2b) is designed as a deflecting mirror, by means of which the outgoing reflected light beam (5a) can be returned to the reflection surface (3) after reflection at two preceding deflecting mirrors (16a, 16b) in order to be guided from there to an optical device (15) or an object to be examined in order to scan this in the Y-direction.
14. Device according to claim 12 or 13, characterized in that light incident on the Y-scanning device (2b) can be guided through a lens (12c) or third lens (12c) and light emerging from the Y-scanning device (2b) can be guided through a further lens (12d) or fourth lens (12d).
15. Device according to one of the preceding claims, characterized in that at least two lenses (12a, 12b, 12c, 12d) are arranged confocally to one another and / or with the interposition of a deflection mirror (16b) or of two deflection mirrors (16a, 16b).