Illumination unit for digital pathology scanning

Abstract

The present invention relates to digital pathology, and relates in particular to a digital pathology scanner illumination unit. In order to provide digital pathology scanning with improved illumination, a digital pathology scanner illumination unit (10) is provided that comprises a light source (12), a light mixing chamber (14), and a light diffuser (16). The light source comprises a plurality of light elements (18) that are arranged longitudinally along a linear extension direction. The mixing chamber comprises a transparent volume (22) providing a mixing distance (DM) between the plurality of the light elements and the light diffuser such that light with a uniform intensity is provided at a downstream edge (26) of the mixing chamber; and the mixing chamber is arranged, in terms of light propagation, between the plurality of the light elements and the light diffuser. Further, the light diffuser comprises a diffusing material such that the light is transformed into light that has uniformity at different angles, in particular low angles.

Claims

1. A digital pathology scanner illumination unit, comprising: a light mixing chamber; a light diffuser; and a plurality of light emitting diodes arranged longitudinally along a linear extension direction, wherein light emanates from a side of each of the light emitting diodes that is parallel to the linear extension direction; wherein the mixing chamber comprises a transparent volume providing a mixing distance (D.sub.M) between the plurality of light emitting diodes and the light diffuser such that light with a uniform intensity is provided at a downstream edge of the mixing chamber, and wherein the mixing chamber is arranged, in terms of light propagation, between the plurality of light emitting diodes and the light diffuser; wherein the light diffuser comprises a diffusing material such that the light is transformed into light having uniformity at different angles, in particular low angles; wherein the light mixing chamber is provided as a first step of aligning the light such that the light is having uniform intensity before the light enters the light diffuser, and the light diffuser is provided subsequently for ensuring uniform illumination also in respect to the uniformity at different angles; and wherein uniformity of the light emanating from the light diffuser is provided as a light distribution along a linear extension direction.

2. The digital pathology scanner illumination unit of claim 1, wherein the light diffuser is provided as a volume light diffuser.

3. The digital pathology scanner illumination unit of claim 1, wherein the mixing chamber is provided with a mixing chamber height (MC.sub.B) of minimum 20 mm and a mixing chamber length (MC.sub.L) of minimum 40 mm.

4. The digital pathology scanner illumination unit of claim 1, wherein the mixing chamber is provided as a light guide channel with a channel depth (D.sub.C) in light radiation direction; and wherein the light guide channel is enclosed on the sides by reflective side-walls that provide the light guidance.

5. The digital pathology scanner illumination unit of claim 1, wherein the mixing chamber is provided as a solid block made from a transparent material with a refractive index larger than 1.

6. The digital pathology scanner illumination unit of claim 1, wherein the mixing chamber is provided as an air mixing cavity enclosed by side walls covered with a reflective coating.

7. The digital pathology scanner illumination unit of claim 2, wherein the volume light diffuser is provided as a light scattering translucent plate with a thickness of at least 3 mm.

8. The digital pathology scanner illumination unit of claim 1, wherein a cover is provided on the light diffuser; wherein the cover comprises an aperture for light emanating from the light diffuser.

9. The digital pathology scanner illumination unit of claim 1, wherein the digital pathology scanner illumination unit is provided as an illumination sub-module configured to be combined with at least one further illumination submodule in the linear extension direction; wherein the plurality of light emitting diodes are provided along the linear extension direction with pitch; and wherein a first and a last of the plurality of light emitting diodes of each sub-module are arranged to a sideward edge of the mixing chamber with a distance of half the pitch.

10. A digital pathology scanner, comprising: an object receiving device; an illumination device; an imaging device; and an image data processor; wherein the object receiving device is configured to receive at least one pathology slide comprising a probe to be analyzed; wherein the illumination device comprises the digital pathology scanner illumination unit of claim 1 that is configured to illuminate the pathology slide; wherein the imaging device is configured to acquire images of the illuminated pathology slide; and wherein the image data processor is configured to generate image data of the respective images and to provide the image data for further purposes.

11. The digital pathology scanner of claim 10, wherein for image acquisition, a relative scanning movement of the pathology slide and the illumination device as well as the imaging device in relation to each other is provided along a scanning direction; and wherein the linear extension direction of the plurality of light emitting diodes is arranged transverse to the scanning direction.

12. The digital pathology scanner of claim 10, wherein an imaging optics is provided that comprises at least one lens; wherein the imaging optics is arranged between the object receiving device and the imaging device; and wherein the imaging optics is configured for low NA imaging with a range of the NA lower than 0.1.

13. The digital pathology scanner of claim 10, wherein the digital pathology scanner illumination unit is provided for low-resolution imaging; and wherein the illumination device further comprises a high-resolution illumination unit for high-resolution imaging.

14. The digital pathology scanner of claim 10, wherein the object receiving device provides a receiving plane with a distance to the mixing chamber of approximately 20 mm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Exemplary embodiments of the invention will be described in the following with reference to the following drawings:

(2) FIG. 1 schematically shows a perspective view of an example of a digital pathology scanner illumination unit;

(3) FIG. 2A shows a schematic cross-section through an example of a digital pathology scanner illumination unit;

(4) FIG. 2B shows a longitudinal cross-section in a schematic illustration of the illumination unit of FIG. 2A;

(5) FIG. 3 shows a further example of a cross-section through a digital pathology scanner illumination unit; and

(6) FIG. 4 shows an example of a digital pathology scanner in a schematic illustration.

DETAILED DESCRIPTION OF EMBODIMENTS

(7) FIG. 1 shows a perspective schematic illustration of a digital pathology scanner illumination unit 10 with a light source 12, a mixing chamber 14 and a light diffuser 16. The light source 12 is provided with a plurality of light elements 18, for example LEDs mounted on a printed circuit board 20. The light elements 18 are arranged longitudinally along a linear extension direction, indicated with an arrow 19.

(8) The mixing chamber 14 comprises a transparent volume 22 providing a mixing distance D.sub.M, indicated with a first double arrow 24 between the plurality of the light elements 18 and the light diffuser 16, such that light with a uniform intensity is provided at a downstream edge 26 of the mixing chamber 14. The mixing chamber 14, or light mixing chamber, is arranged, in terms of light propagation, between the plurality of light elements 18 and the light diffuser 16. The light diffuser 16 comprises a diffusing material such that the light is transformed into light having uniformity at different angles, in particular low angles. The mixing chamber 14 is having a mixing chamber width MC.sub.W, and the mixing distance D.sub.M could also be referred to as mixing chamber height, MC.sub.H. Further, the mixing chamber 14 is having a mixing chamber length, MC.sub.L.

(9) The mixing chamber width MC.sub.W is indicated with a double arrow 27, and the mixing chamber length MC.sub.L is indicated with a further double arrow 28.

(10) For example, the light diffuser 16 is provided as a volume light diffuser, for example as a light scattering translucent plate 30 (see also FIGS. 2A, 2B and 3). The translucent plate 30 may have a thickness of at least 3 mm.

(11) The mixing chamber may have a mixing chamber height, or mixing distance D.sub.M, of minimum 20 mm and a mixing chamber length MC.sub.L of minimum 40 mm, for example 80 mm.

(12) It is noted that in FIG. 1, the mixing chamber 14 is provided with a length such that the mixing chamber is arranged covering the extension of the light elements 18. However, in an option (see also below), the mixing chamber 14 is provided with a length such that a distance from the last light element 18, e.g. a last LED, to the wall of the mixing chamber 14 is 0.5 (i.e. half) of the distance between the other light elements 18. This portion is shown in FIG. 2b, where the mixing chamber is having side walls (i.e. the walls at the side ends) that are arranged such that the distance to the LEDs is half the distance between the LEDS, e.g. to allow a combination (not shown) of several such mixing chambers along the extension direction, covered by a light diffuser arrangement comprising several light diffusers that are combined in a similar way along the extension direction. In another example, a light diffuser arrangement comprises a continuous light diffuser (plate) extending across several mixing chambers.

(13) The mixing chamber 14 is provided as a light guide channel 32, as indicated in FIG. 2A and FIG. 3 that are showing cross-sections of two different embodiments. The light guide channel 32 has a channel depth D.sub.C, indicated in FIG. 2A with a double arrow 34, which is similar to the mixing distance D.sub.M. The light guide channel is enclosed on the sides by reflective side walls 36 that provide the light guidance. In FIG. 2A, the light source 12 is schematically indicated with one of the light elements 18, for example an LED, that emanates light, as indicated with thin line arrows 38. The light is reflected on the inner sides of the reflective sidewalls.

(14) In FIG. 2B, the light source 12 is shown with a number of the plurality of the light elements 18, but only for three of them, respective light emanation radiation is indicated by respective arrows 40.

(15) FIGS. 2A and 2B show an example where the mixing chamber 14 is provided as a solid block 42 made from a transparent material with a refractive index larger than 1. Hence, the light emanating from the light source 12, i.e. the light elements 18, is being mixed in the mixing chamber such that light with a uniform intensity is provided at the downstream edge 26 of the mixing chamber 12. The light diffuser 16 then provides that the light is transformed into light having uniformity at different angles. This is provided, in an example, as indicated above, with the light scattering translucent plate 30.

(16) The solid block 42 can be provided as glass or transparent plastic material. In another example, shown in FIG. 3, the mixing chamber 12 is provided as an air mixing cavity 44 enclosed by side walls 46 covered with a reflective coating 48.

(17) As an option, a cover 50 is provided, as indicated in FIG. 1. The cover 50 is provided on the light diffuser 16 and the cover comprises an aperture 52 for light emanating from the light diffuser 16. The aperture 52 may be provided as a slit having an opening width O.sub.W, indicated with double arrow 54 and an opening length O.sub.L, indicated with a double arrow 56. The slit is smaller than the upper edge of the diffuser, and may also be smaller than a cross-section of the mixing chamber.

(18) The cover is provided for the example of the solid material mixing chamber, and also for the air-guide mixing chamber. As a further option, the digital pathology scanner illumination unit 10 is provided as an illumination sub-module that is configured for a combination with at least one further illumination sub-module in the linear extension direction.

(19) The light elements 18 are provided along the linear extension direction with a pitch and the first and the last light elements of each sub-module are arranged to a sideward edge of the mixing chamber with a distance of half the pitch. This allows a combination of sub-modules, but keeps the appearance of the light elements constant across the abutting end faces of the adjacent sub-modules.

(20) FIG. 4 shows an example of a digital pathology scanner 100 comprising an object receiving device 102, an imaging device 104 and image data processor 106. The imaging device 104 is arranged above the object receiving device 102. Further, an illumination device 108 is provided according to one of the above-mentioned examples of the digital pathology scanner illumination unit 10. The illumination device 108 is arranged below, i.e. opposite the object receiving device 102. This allows a transmissive illumination of a probe. An image can be provided in a transmission mode. For a reflective mode, the imaging device 104 would have to be arranged on the same side as the illumination device 108. The object receiving device 102 is configured to receive at least one pathology slide 110 comprising a probe to be analyzed. The digital illumination device 108, i.e. the digital pathology scanner illumination unit 10, provides illumination towards the pathology slide 110 such that the imaging device 104, which is configured to acquire images of the illuminated pathology slide 110, can generate image data and transfer same to the image data processor 106. The image data processor 106 is configured to generate image data of the respective images and to provide the image data for further purposes, as indicated with arrow 112.

(21) For image acquisition, a relative scanning movement (indicated with a double arrow 114) of the pathology slide and the digital illumination device as well as the imaging device in relation to each other is provided along a scanning direction.

(22) As an option, an imaging optics (not shown) can be provided that comprises at least one lens. The imaging optics can be arranged between the slide 110 and the camera, i.e. the imaging device 104. The imaging optics can be configured for low NA imaging with a range of the NA lower than 0.1. For example, an NA value of lower than 0.05 is provided.

(23) The digital pathology scanner illumination unit 10 may be provided for low resolution imaging. As an option, also indicated in FIG. 4, the illumination device 108 further comprises a high resolution illumination unit 115 for high resolution imaging.

(24) As a further option, the object receiving device 102 is providing a receiving plane 116 with a distance to the mixing chamber 14 of approximately 20 mm.

(25) According to an aspect, not further shown in detail, a combination of light mixing and light diffusion is provided to achieve uniform illumination of the surface of interest, for example a pathology slide even at low NA imaging. As mentioned above, in a first step, the light of individual sources is mixed with the help of a mixing box, e.g. the mixing chamber, to achieve spatial uniformity and subsequently a diffuser, for example a volume diffuser, is used to produce angular position mixing. Hence, the role of the mixing chamber is to achieve a uniform illumination at the top exit of the mixing chamber. However, at this point, the individual modules/LEDs may still be visible when observed at low NA. Therefore, subsequently, the diffuser, preferably the volume diffuser, is used to ensure uniform illumination even when investigated at low NA.

(26) As an effect, the light at the exit of the mixing chamber is uniform when all angles are observed, however at lower angles the individual LED modules may still be visible. Therefore, the volume diffuser is used to solve this.

(27) In an example, to ensure optimal mixing conditions, the geometry of the mixing chamber is matched with the pitch of the individual modules. The distance between the last LED and the edge of the imaging chamber is provided to be half the pitch of the individual LEDs.

(28) As a result, an illumination unit with an improved quality of emanating light is provided to account for imaging quality. For example, the improved illumination allows a facilitated identification of tissue area and also of slight defects.

(29) It has to be noted that embodiments of the invention are described with reference to different subject matters. However, a person skilled in the art will gather from the above and the following description that, unless otherwise notified, in addition to any combination of features belonging to one type of subject matter, also any combination between features relating to different subject matters is considered to be disclosed with this application. However, all features can be combined providing synergetic effects that are more than the simple summation of the features.

(30) While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. The invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing a claimed invention, from a study of the drawings, the disclosure, and the dependent claims.

(31) In the claims, the word comprising does not exclude other elements or components, and the indefinite article a or an does not exclude a plurality. The mere fact that certain measures are re-cited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.