Optical arrangement for compensation of thermally-induced astigmatism of lens

Abstract

An apparatus includes a sample stage region, an optical assembly, and a camera assembly. The optica! assembly includes an objective element, a tube lens, and a compensating element. The objective element provides a field of view, at least a portion of the sample stage region is within the field of view. The objective element has a variable astigmatism. The tube lens is configured to receive light transmitted through the objective element and further transmit the light through an image space. The compensating element is in the image space. The compensating element is configured to induce a second astigmatism. The second astigmatism is configured to offset the variable astigmatism. The camera assembly is configured to receive light transmitted from the compensating assembly.

Description

An apparatus includes a sample stage region, an optical assembly, and a camera assembly. The optical assembly includes an objective lens element, a barrel lens, and a compensation element. The objective lens element provides a field of view, within which at least a portion of the sample stage region is located. The objective lens element has variable astigmatism. The barrel lens is configured to receive light transmitted through the objective lens element and further transmit the light through an image space. The compensation element is located in the image space. The compensation element is configured to induce a second astigmatism. The second astigmatism is configured to cancel the variable astigmatism. The camera assembly is configured to receive light transmitted from the compensation element.

Claims

What is claimed is:

1. An apparatus, comprising: a sample stage region; an optical assembly including: an objective element providing a field of view, at least a portion of the sample stage region being within the field of view, the objective element having a variable astigmatism, a tube lens, the tube lens being configured to receive light transmitted through the objective element and further transmit the light through an image space, a compensating assembly in the image space, the compensating assembly being configured to induce a second astigmatism, the second astigmatism being configured to offset the variable astigmatism; and a camera assembly configured to receive light transmitted from the compensating assembly.

2. The apparatus of claim 1, the compensating assembly being operable to vary the second astigmatism to thereby dynamically offset the variable astigmatism of the objective element.

3. The apparatus of claim 2, further comprising a processor, the processor being operable to control the compensating assembly to thereby vary the second astigmatism.

4. The apparatus of claim 3, the processor being operable to control the compensating assembly to thereby vary the second astigmatism based on a predetermined adjustment profile.

5. The apparatus of claim 3, the processor being operable to determine an astigmatism value of the objective element.

6. The apparatus of claim 5, the processor being operable to control the compensating assembly to thereby vary the second astigmatism based on the determined astigmatism value of the objective element.

7. The apparatus of any of claims 1 through 6, the compensating assembly comprising a first optically transmissive plate and a second optically transmissive plate.

8. The apparatus of claim 7, the first optically transmissive plate being tilted at a first angle about a first axis, the second optically transmissive plate being tilted at a second angle about a second axis.

9. The apparatus of claim 8, the first optically transmissive plate and the second optically transmissive plate being positioned along an image axis, the first axis being orthogonal to the image axis, the second axis being parallel with the first axis.

10. The apparatus of any of claims 8 through 9, the first angle having a magnitude and direction equal and opposite to a magnitude and direction, respectively, of the second angle.

11. The apparatus of any of any of claims 8 through 10, the compensating assembly further comprising a first actuator, the first actuator being operable to drive movement of one or both of the first optically transmissive plate about the first axis or the second optically transmissive plate about the second axis.

12. The apparatus of claim 11, the compensating assembly further comprising a linkage, the first actuator and the linkage being configured to cooperate to drive movement of the first optically transmissive plate about at the first axis and the second optically transmissive plate about the second axis concomitantly.

13. The apparatus of claim 11, the compensating assembly further comprising a second actuator, the first actuator being coupled with the first optically transmissive plate tothereby drive movement of the first optically transmissive plate about at the first axis, the second actuator being coupled with the second optically transmissive plate to thereby drive movement of the second optically transmissive plate about at the second axis.

14. The apparatus of any of claims 11 through 13, the first actuator comprising a motor.

15. The apparatus of any of claims 11 through 14, the compensating assembly further comprising a first gear and a second gear, the first optically transmissive plate to rotate unitarily with the first gear, the second optically transmissive plate to rotate unitarily with the second gear.

16. The apparatus of claim 15, the first gear being positioned to mesh directly with the second gear.

17. The apparatus of any of claims 15 through 16, the compensating assembly further comprising a crank arm coupled with the first gear, the first actuator to drive rotary motion of the crank arm, the crank arm to drive rotary motion of the first gear.

18. The apparatus of any of claims 11 through 17, the compensating assembly further including housing elements forming a box around the first optically transmissive plate and the second optically transmissive plate.

19. The apparatus of any of claims 11 through 18, the compensating assembly further comprising a first shaft, a second shaft, and a base plate, the first shaft and the second shaft passing through the base plate, the first shaft to drive movement of the first optically transmissive plate about the first axis, the second shaft to drive movement of the second optically transmissive plate about the second axis.

20. The apparatus of any of claims 1 through 6, the compensating assembly comprising a first optically transmissive element and a reflective element.

21. The apparatus of any of claims 1 through 20, the compensating assembly comprising a deformable element.

22. The apparatus of claim 21, the deformable element being optically transmissive.

23. The apparatus of claim 21, the deformable element being reflective.

24. The apparatus of any of claims 1 through 23, further comprising a heating element, the heating element being operable to heat the objective element and thereby vary the astigmatism of the objective element.

25. The apparatus of claim 24, the heating element comprising a source of laser light.

26. An apparatus, comprising: a sample stage region; an optical assembly including: an objective element providing a field of view, at least a portion of the sample stage region being within the field of view, the objective element having an astigmatism that is variable based on a temperature of the objective element, a tube lens, the tube lens being configured to receive light transmitted through the objective element and further transmit the light through an image space, a first compensating element in the image space, the first compensating element being configured to induce a second astigmatism, a second compensating element in the image space, the second compensating element being configured to induce a third astigmatism, the second and third astigmatisms being configured to cooperate to offset the variable astigmatism; and a camera assembly configured to receive light transmitted from the compensating assembly.

27. The apparatus of claim 26, the first compensating element being titled at a first angle, the second compensating element being tilted at a second angle that is equal and opposite to the first angle.

28. The apparatus of any of claims 26 through 27, the first compensating element being movable relative to the objective element to adjust the second astigmatism, the second compensating element being movable relative to the objective element to adjust the third astigmatism.

29. The apparatus of claim 28, further comprising a controller, the controller being configured to drive movement of the first compensating element and the second compensating element to track thermally induced changes in the astigmatism of the objective element.

30. The apparatus of claim 29, the controller being further configured to track the thermally induced changes in the astigmatism of the objective element.

31. The apparatus of claim 30, the controller being configured to process images captured by the camera assembly, the controller being further configured to determine and track the thermally induced changes in the astigmatism of the objective element based on the processed images.

32. The apparatus of any of claims 29 through 31, the controller being configured to drive movement of the first compensating element and the second compensating element based on a predetermined adjustment profile.

33. The apparatus of claim 32, the controller being configured to define the predetermined adjustment profile.

34. The apparatus of claim 33, the controller being configured to execute a calibration routine and define the predetermined adjustment profile through the calibration routine.

35. The apparatus of any of claims 26 through 34, the sample stage region being configured to receive a flow cell.

36. A method comprising: receiving light from a reaction site through an objective element, the objective element having an astigmatism, the light passing further through a compensation assembly, the compensation assembly providing a compensating astigmatism, the compensating astigmatism offsetting the astigmatism of the objective element; heating the objective element, the astigmatism of the objective element changing in response to the heating; and adjusting the compensation assembly to thereby change the compensating astigmatism, thereby offsetting the changing astigmatism of the objective element.

37. The method of claim 36, further comprising irradiating the reaction site with excitation light.

38. The method of claim 37, the excitation light passing through the objective element to reach the reaction site.

39. The method of claim 38, the excitation light causing the heating of the objective element.

40. The method of any of claims 37 through 39, the excitation light comprising laser light.

41. The method of any of claims 36 through 40, the compensation assembly comprising a first compensating element, the act of adjusting the compensation assemblycomprising pivoting the first compensating element in a first angular direction about a first pivot axis through a first pivotal range of motion.

42. The method of claim 41, the compensation assembly further comprising a second compensating element, the act of adjusting the compensation assembly further comprising pivoting the second compensating element in a second angular direction about a second pivot axis through a second pivotal range of motion.

43. The method of claim 42, the second angular direction being opposite to the first angular direction.

44. The method of any of claims 42 through 43, the second pivot axis being parallel with the first pivot axis.

45. The method of any of claims 42 through 44, the second pivotal range of motion being equal to the first pivotal range of motion.

46. The method of claim 41, an image axis of the light shifting in response to pivoting the first compensating element in a first angular direction about a first pivot axis through a first pivotal range of motion, the method further comprising moving a camera based on the shifting of the image axis of the light, the camera capturing at least some of the light.

47. The method of claim 41, an image axis of the light shifting in response to pivoting the first compensating element in a first angular direction about a first pivot axis through a first pivotal range of motion, the method further comprising moving a reflecting element based on the shifting of the image axis of the light.

48. The method of claim 47, the act of moving the reflecting element comprising pivoting the reflecting element.

49. The method of any of claims 47 through 48, the act of moving the reflecting element comprising deforming the reflecting element.

50. The method of any of claims 47 through 49, the reflecting element redirecting the light toward a camera.

51. The method of claim 50, the camera maintaining a fixed position during movement of the reflecting element.

52. The method of any of claims 36 through 40, the compensation assembly comprising a deformable compensating element, the act of adjusting the compensation assembly comprising deforming the compensating element.

53. The method of claim 52, the light being emitted along an image axis, the act of deforming the compensating element comprising deforming the compensating element along the image axis.

54. The method of any of claims 36 through 53, further comprising capturing the light with a camera, the compensation assembly being interposed between the objective element and the camera.

55. The method of any of claims 36 through 53, further comprising performing sequencing by synthesis.

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