APPARATUS FOR THE DETECTION OF LIGHT IN A SCANNING MICROSCOPE

• US 20100214654A1
• Filed: 05/06/2008
• Published: 08/26/2010
• Est. Priority Date: 05/22/2007
• Status: Active Grant

• Current Assignee: Leica Microsystems Gmbh (Danaher Corporation)
• Original Assignee: Leica Microsystems Gmbh (Danaher Corporation)
• Inventors: Seyfried, Volker, Birk, Holger
• Granted Patent: US 8,503,076 B2
• Time in Patent Office: Days
• US Class Current: 359/385
• CPC Class Codes: G01J 1/44 Electric circuits for command of an exposure part G03B7/02
• CPC Class Codes: G01J 1/46 using a capacitor
• CPC Class Codes: G01J 3/2803 using photoelectric array detector
• CPC Class Codes: G02B 21/0032 Optical details of illumination, e.g. light-sources, pinholes, beam splitters, slits, fibers G02B21/0036 - G02B21/008; means for illumination of specimens in general G02B21/06
• CPC Class Codes: G02B 21/0096 with photometer devices photometers per se G01J
• CPC Class Codes: H01L 31/107 the potential barrier working in avalanche mode, e.g. avalanche photodiodes

Abstract

A light detector for use in a line scanning microscope and a microscope comprising such a light detector are described. The light detector comprises—a line array of avalanche semiconductor detectors; and an electronic trigger circuit that is adapted to operate the avalanche semiconductor detectors in at least one of a Geiger mode with internal charge amplification and in a linear mode. The trigger circuit further comprises a parallel counter that is designed to read out in parallel light pulses detected by the avalanche semiconductor detectors. The parallel counter is adapted to accumulate the light pulses detected by the avalanche semiconductor detectors over a preset counting time.

Claims

1. A light detector for use in a line scanning microscope, comprising:

a line array of avalanche semiconductor detectors; and

electronic trigger circuit that is adapted to operate the avalanche semiconductor detectors in at least one of a Geiger mode with internal charge amplification and in a linear mode, the trigger circuit further comprising a parallel counter, wherein the parallel counter is designed to read out in parallel light pulses detected by the avalanche semiconductor detectors and the parallel counter is adapted to accumulate the light pulses detected by the avalanche semiconductor detectors during a preset counting time.

2. The light detector according to claim 1, the parallel counter comprising at least one of the following elements:

an FPGA, a CPLD.

3. The light detector according to claim 1, wherein the line array is chosen from a group line arrays having:

256 and above avalanche semiconductor detectors;

512 and above avalanche semiconductor detectors; and

1024 and above avalanche semiconductor detectors.

4. The light detector according to claim 1, the linear filling factor of the line array being chosen from a group consisting of:

at least 50%;

at least 70%; and

at least 80%.

5. The light detector according to claim 1, wherein the line array is a monolithic line array.

7. The light detector according to claim 1, wherein the light detector comprises at least a first line array and at least a second line array, whereby in each instance at least a first avalanche semiconductor of the first line array and a second avalanche semiconductor of the second line array are assigned to each other, and the trigger circuit is being adapted to obtain the sum of the light pulses detected by the first avalanche semiconductor detector and the second avalanche semiconductor detector.

8. The light detector according to claim 1, wherein signals of the first avalanche semiconductor detector and the second avalanche semiconductor detector are accumulated to a sum signal and the sum signal is supplied to a common counter input of the parallel counter.

9. The light detector according to claim 7, wherein signals of the first avalanche semiconductor detector and signals of the second avalanche semiconductor detector are supplied to separate counting inputs of the parallel counter, and the parallel counter is adapted to accumulate the signals of the first avalanche semiconductor detector and signals of the second avalanche semiconductor detector.

10. The light detector according to claim 1, wherein the parallel counter comprises a memory area with a plurality of memory cells, the memory cells are assigned to avalanche semiconductor detectors and present values are assigned to the memory cells, and the trigger circuit control is adapted to temporarily increase or lower the value of a memory cell when the avalanche semiconductor detector assigned to said memory cell detects a light pulse.

11. The light detector according to claim 10, wherein the trigger circuit is adapted to accumulate the values of memory cells assigned to each other in preset time intervals and to subsequently reset the values of the memory cells to the preset values.

12. The light detector according to claim 1, the line array further comprising a plurality of micro lenses that are adapted to focus incident light onto one or several of the avalanche semiconductor detectors in each case.

13. The light detector according to claim 1, the trigger circuit further comprising a device for actively quenching the avalanche semiconductor detectors, which device can be switched by means of a signal of the avalanche semiconductor detectors whereby an impedance of an RC circuit comprising the avalanche semiconductor detectors can be changed.

22. The light detector according to claim 8, wherein signals of the first avalanche semiconductor detector and signals of the second avalanche semiconductor detector are supplied to separate counting inputs of the parallel counter, and the parallel counter is adapted to accumulate the signals of the first avalanche semiconductor detector and signals of the second avalanche semiconductor detector.

6. (canceled)

14. (canceled)

15. The microscope comprising:

a light source for illuminating a sample;

a scanning device for scanning the sample with a light beam emitted by the light source; and

a light detector comprising;

a line array of avalanche semiconductor detectors; and

an electronic trigger circuit that is adapted to operate the avalanche semiconductor detectors in at least one of a Geiger mode with internal charge amplification and in a linear mode, the trigger circuit further comprising a parallel counter, wherein the parallel counter is designed to read out in parallel light pulses detected by the avalanche semiconductor detectors and the parallel counter is adapted to accumulate the light pulses detected by the avalanche semiconductor detectors during a preset counting time;

wherein

the light detector is arranged in the microscope such that it detects light that is at least one of emitted, transmitted and reflected by the sample.

16. The microscope according to claim 15, wherein the microscope is confocal microscope.

19. The microscope according to claim 15, further comprising at least one spectral separating element, the spectral separating element being adapted such that at least two different wave length ranges of an area of the sample are imaged onto different avalanche semiconductor detectors of the light detector.

20. The microscope according to claim 16, further comprising at least one spectral separating element, the spectral separating element being adapted such that at least two different wave length ranges of an area of the sample are imaged onto different avalanche semiconductor detectors of the light detector.

21. The microscope according to claim 19, wherein the spectral separating element is and least one of a prism and a grid.

17. (canceled)

18. (canceled)