Confocal line-scanning ophthalmoscope
View Patent ↗A line-scanning ophthalmoscope includes a light source to provide a light beam to an object of interest, a beam separating device to receive the light beam, provide the light beam to a scanning device and substantially separate the light beam and the returning light beam from the object of interest, a scanning device to direct the light beam to the object of interest for scanning the object of interest; to receive the light beam returning from the object of interest; and to direct at least part of the reflected light beam towards a detector; and a further scanning device to convert the light beam to a line-shaped light beam.
1. A line-scanning ophthalmoscope, comprising:
a light source to provide a light beam to an object of interest;
a beam separating device to receive the light beam, provide the light beam to a scanning device and substantially separate the light beam and a returning light beam from the object of interest;
a scanning device to direct the light beam to the object of interest for scanning the object of interest with a line-shaped light beam; to receive the returning light beam from the object of interest; and to direct at least part of the returning light beam towards a detector;
a line generating device to convert the light beam to the line-shaped light beam for scanning the object of interest, wherein the line generating device is an arrayed line generating device; and
a further scanning device for providing a displacement of the light beam or the line-shaped light beam in a direction substantially parallel to the line of the line-shaped light beam;
wherein the arrayed line generating device comprises an array of reflective or refractive ridges for converting the light beam to the line-shaped light beam.
2. The ophthalmoscope according to claim 1 wherein the light source is a laser light source.
3. The ophthalmoscope according to claim 1 wherein the arrayed line generating device is arranged to convert the light beam to a superposition of a plurality of line-shaped beams forming the line-shaped light beam.
4. The ophthalmoscope according to claim 1 wherein the line generating device is arranged in an optical path of the light beam between the beam separating device and the scanning device.
5. The ophthalmoscope according to claim 1 wherein the line generating device is arranged in an optical path of the light beam before the beam separating device.
6. The ophthalmoscope according to claim 1 wherein the array of reflective or refractive ridges is further provided with an optical element such as a transmissive plate having a step-wise varying thickness for generating distinct phase shifts to distinct light beams emanating from the array of ridges.
7. The ophthalmoscope according to claim 1 wherein the arrayed line generating device has a frontside having a step-wise varying thickness.
8. The ophthalmoscope according to claim 1 wherein the detector is a line sensor.
9. The ophthalmoscope according to claim 1 , wherein the further scanning device is arranged to provide the displacement at a fast scanning frequency that is comparatively high compared to a scanning frequency of the scanning device for scanning the object of interest.
10. The ophthalmoscope according to claim 9 wherein an amplitude of the displacement is at least as large as a distance between two interference fringes of the arrayed line generating device.
11. The ophthalmoscope according to claim 10 , whereby the detector is a line detector, and the fast scanning frequency is an integer multiple or integer fraction of an exposure frequency of the line detector.
12. The ophthalmoscope according to claim 1 wherein the arrayed line generating device is arranged to provide a plurality of line-shaped light beams for scanning the object of interest.
13. The ophthalmoscope according to claim 12 wherein the plurality of line-shaped light beams are arranged to, in use, enter the object of interest on different locations.
14. The ophthalmoscope according to claim 1 wherein the arrayed line generating device comprises a plurality of optical elements, each arranged to receive only part of the light beam.
15. The ophthalmoscope according to claim 1 wherein the arrayed line generating device comprises a plurality of optical elements arranged adjacent each other in a direction substantially perpendicular to a direction of the light beam.
16. A line-scanning ophthalmoscope, comprising:
a light source to provide a light beam to an object of interest;
a beam separating device to receive the light beam, provide the light beam to a scanning device and substantially separate the light beam and a returning light beam from the object of interest;
a scanning device to direct the light beam to the object of interest for scanning the object of interest with a line-shaped light beam; to receive the returning light beam from the object of interest; and to direct at least part of the returning light beam towards a detector;
a line generating device to convert the light beam to the line-shaped light beam for scanning the object of interest; and
a further scanning device for in use displacing the light beam or the line-shaped light beam for scanning the object of interest in a direction substantially parallel to the line of the line-shaped light beam, at a frequency that is comparatively high compared to a scanning frequency for scanning the object of interest.
17. The line-scanning ophthalmoscope according to claim 16 wherein the line generating device comprises a cylindrical lens or a Powell lens.