High-Speed Reading by Combining Transmissive Wide Angle View with Reflective Focus View

Abstract

The present invention relates to methods and devices for high-speed reading out information from an at least partially transparent data carrier.

Claims

1-16. (canceled)

17. A method for high-speed reading out information from an at least partially transparent data carrier, the method comprising: illuminating the data carrier with an illuminating light from a first side through a first objective having a numerical aperture of at least 0.5; imaging the data carrier from the first side in a reflection mode through the first objective in order to generate focus view data; imaging the data carrier from a second, opposite side in a transmission mode through a second objective having a numerical aperture of less than 0.3 in order to generate wide angle data; and combining the focus view data and the wide angle data in order to generate an image comprising a wide angle view of at least a section of the data carrier with a subsection of the image having a higher resolution than a rest of the image.

18. The method of claim 17, wherein the second objective has a numerical aperture of less than 0.2.

19. The method of claim 17, wherein the first objective has a numerical aperture of at least 0.7.

20. The method of claim 17, wherein the subsection of the image is arranged in a center of the image.

21. The method of claim 17, wherein a resolution of the subsection of the image is greater than a resolution of the rest of the image by at least a factor of 5.

22. The method of claim 17, wherein a resolution of the subsection of the image is greater than the resolution of the rest of the image by at least a factor of 10.

23. The method of claim 17, wherein the data carrier is illuminated by means of a digital micromirror device and/or a spatial light modulator.

24. The method of claim 17, wherein imaging the data carrier from the first side in the reflection mode through the first objective utilizes structured illumination microscopy (SIM) or saturated structured illumination microscopy (SSIM).

25. The method of claim 17, wherein imaging the data carrier from the second, opposite side in the transmission mode through the second objective utilizes Fourier ptychography.

26. The method of claim 17, wherein the data carrier comprises a ceramic substrate and a ceramic coating layer, wherein a material of the ceramic substrate is different from a material of the coating layer, wherein the coating layer has a thickness no greater than 1 ?m.

27. The method of claim 26, wherein the ceramic substrate comprises at least 90% by weight of one or a combination of: a metal oxide; a metal nitride; a metal carbide; a metal boride; or a metal silicide.

28. The method of claim 26, wherein the ceramic coating layer comprises one or a combination of: a metal nitride; a metal carbide; a metal oxide; a metal boride; or a metal silicide.

29. The method of claim 26, wherein the ceramic substrate is transparent to a wavelength of the illuminating light.

30. The method of claim 29, wherein the ceramic substrate comprises one or a combination of: sapphire (Al.sub.2O.sub.3); silica (SiO.sub.2); zirconium silicate (Zr(SiO.sub.4)); or zirconium dioxide (ZrO.sub.2).

31. The method of claim 17, wherein the data carrier comprises orientation or registration markers.

32. A device for high-speed reading out information from an at least partially transparent data carrier, the device comprising: a substrate holder for mounting the data carrier; a first objective having a numerical aperture of at least 0.5 on a first side of the substrate holder; a second objective having a numerical aperture of less than 0.3 on a second, opposite side of the substrate holder; a light source for illuminating the data carrier mounted on the substrate holder from the first side through the first objective; a first image detector for imaging the data carrier from the first side in a reflection mode through the first objective in order to generate focus view data; a second image detector for imaging the data carrier from the second side in a transmission mode through the second objective in order to generate wide angle data; and a central processing unit adapted to combine the focus view data and the wide angle data received from the first and second image detectors in order to generate an image comprising a wide angle view of at least a section of the data carrier with a subsection of the image having a higher resolution than a rest of the image.

33. The device of claim 32, wherein the second objective has a numerical aperture of less than 0.2.

34. The device of claim 32, wherein the first objective has a numerical aperture of at least 0.7.

35. The device of claim 32, further comprising a digital micromirror device arranged between the light source and the first objective.

36. The device of claim 32, further comprising a spatial light modulator arranged between the light source and the first objective.

Description

[0023] The present invention will now be further illustrated with reference to the figures, which show:

[0024] FIG. 1: a schematic of an optical setup for generating focus view data;

[0025] FIG. 2: a schematic of an optical setup for generating wide angle data;

[0026] FIG. 3: a combination of the setups according to FIGS. 1 and 2; and

[0027] FIG. 4: a schematic of a preferred embodiment of a device according to the present invention.

[0028] FIG. 1 schematically shows an example of an optical setup for imaging an at least partially transparent data carrier 2 mounted on a substrate holder 1 in reflection mode in order to generate focus view data 20. The at least partially transparent data carrier 2 is illuminated from a first side (here: a top side) through a high numerical aperture objective 3 by means of an LED 5 and a digital micromirror device 9. Of course, another light source may be utilized and the digital micromirror device is not necessarily required for generating focus view data. Moreover, a spatial light modulator may be utilized instead of the DMD 9. Light being reflected or scattered by the data carrier 2 can be imaged from the first side (here: the top side) in reflection mode through the same high numerical aperture objective 3 by means of, e.g., a CCD camera 6 and a semi-transparent mirror 10. This imaging technique generates focus view data 20 schematically illustrated at the bottom of FIG. 1. The exemplary focus view data 20 shown in FIG. 1 have been generated by an Olympus BX 51 with 100? microscope objective with an NA of 0.7. The sample shown is a ceramic material comprising circular recesses generated by laser pulses.

[0029] FIG. 2 schematically shows an example of an optical setup for generating wide angle data 21. The data carrier 2 being mounted on the substrate holder 1 is again illuminated from a first side (here: the top side) through the high numerical aperture objective 3 by means of an LED 5, DMD 9 and the semi-transparent mirror 10 (which would not be required for this part of the setup). However, contrary to FIG. 1, in case of FIG. 2 imaging is performed from a second, opposite side (here: the bottom side) in transmission mode through a low numerical aperture objective 4 in order to generate wide angle data 21. Again, a CCD camera 7 or any other image detector may be utilized for imaging. The wide angle data shown at the bottom of FIG. 2 have been taken from the sample discussed above, utilizing an Olympus BX 51 with 10? microscope objective with an NA of 0.26.

[0030] According to the present invention the optical setups shown in FIGS. 1 and 2 are combined in a single device for high-speed reading out information from the at least partially transparent data carrier 2. This is exemplary shown in FIG. 3, where all components of FIGS. 1 and 2 have been combined accordingly. The setup allows for imaging the data carrier 2 from the first (top) side in reflection mode in order to generate focus view data and for imaging the data carrier 2 from a second, opposite (bottom) side in transmission mode in order to generate wide angle data. For both imaging steps, illumination can take place from the first, top side through the high numerical aperture objective 3.

[0031] While a very simple setup with only two CCD cameras 6 and 7 for imaging is shown in FIG. 3, it will be evident from the above discussion that either or both of the imaging components of the setup may be more elaborate utilizing, for example, SIM, SSIM and/or Fourier ptychography. For this purpose, the DMD 9 may generate specific illumination patterns required for those imaging techniques and an additional processing unit may be required in order to control the DMD 9 as well as the CCD cameras 6 and 7.

[0032] Of course, the setup shown in FIG. 3 may not only be used for reading out data from the data carrier 2, but could also be utilized for encoding data on the data carrier 2 using an additional laser 11. The encoding process has been described in detail in the above-mentioned patent applications and need not be further elucidated here.

[0033] The inventive method utilizing the above-discussed setup is schematically depicted in FIG. 4 which, on the left side, again shows the optical setup of FIG. 3 with an additional central processing unit (CPU) 8 being shown in the centre of FIG. 4. Said CPU 8 receives the focus view data 20 from the CCD camera 6 as well as the wide angle data 21 from the CCD camera 7 and combines the data in order to generate an image 22 schematically depicted on the right side of FIG. 4. Said image 22 comprises a wide angle view 21 of at least a section of the data carrier 2 with a subsection 20 of said image having a higher resolution than the rest of the image. Of course, neither the image 22 nor the subsection 20 need be circular as shown in FIG. 4, but could also be rectangular, quadratic or of any other shape. It is, however, preferred that the subsection 20 of the image 22 is arranged in the center of the image 22 as shown in FIG. 4.

[0034] As should be evident from the above, the present invention allows for high-speed reading out information from an at least partially transparent data carrier because the resulting combined image 22 shown in FIG. 4 allows to generate both a broad overview over a large portion of the data carrier 2 and imaging the subsection with a resolution that is sufficient to decode the data or to image the data with the required accuracy. It will thus be possible to, e.g., shift the focus view to another part of the image 22 because the surrounding of the focus view is, albeit not with the same resolution, already visible in the image 22. The resolution of the rest of the image may, however, be great enough to visualize, for example, certain landmarks or orientation markers which will allow the user to identify certain regions on the data carrier which may be of interest to him. Thus, the claimed technique is extremely advantageous for quickly accessing data on a large data carrier encoding information with a high data density.

[0035] For shifting the focus view to another part of the image 22, the device may further comprise a mechanism for shifting the focus view of either or both of the objectives relative to the data carrier. This may be achieved by optical means and/or by a moving stage. For example, the substrate holder 1 may comprise or may be positioned on an XY-stage for moving the data carrier along two directions within one plane. Said XY-stage may be motorized and may be manipulated manually or automatically. For example, suitable software may allow a user to choose a certain area within the wide angle view he/she is interested in, which will then trigger the software to control the XY-stage in such a manner as to allow for generating focus view data of this chosen area.

[0036] In order to allow for identifying regions of interest (either manually or automatically) the data carrier may comprise orientation or registration markers. For example, specific patterns (such as the three square patterns in case of a QR code) may be distributed over the data carrier, which patterns will be visible in the wide angle view and may be utilized to provide orientation on the data carrier to a user or a software automatically navigating over the data carrier. However, depending on the data structure of the data carrier such orientation or registration markers may not be necessary in order to allow for navigating the data carrier. For example, if the data carrier contains image information, the wide angle view may already be sufficient to recognize the relevant portion of the image (even though the image in the wide angle view my be blurry) and to allow a user or a software to identify a region of interest to which the focus view will then be shifted in a next step. If the magnification for both the wide angle view and the focus view is known, then the required shift (e.g. for the XY-stage) in order to focus on the region of interest may be calculated without the presence of any markers.