Eye safety protection from high power laser light

1. A laser safety device, comprising:

a housing having first and second apertures;

a beam splitter optically coupled to the first aperture and configured to divide radiation entering the housing through the first aperture into a first part and a second part;

a photodetector optically coupled to the second part of the radiation and configured to detect a level of the second part of the radiation;

a control circuit coupled to an output of the photodetector and configured to generate a control signal based upon the level of the second part of the radiation detected by the photodetector; and

a reflector array optically coupled to the first part of the radiation and configured to selectively divert the first part of the radiation away from an optical path extending from the first aperture to the second aperture or allow the first part of the radiation to continue along the optical path towards the second aperture in response to the control signal,

wherein the beam splitter is configured such that the optical coupling of the photodetector to the second part of the radiation is unchanged when the reflector array diverts the first part of the radiation from the optical path.

2. The device of claim 1 further comprising:

an absorber configured to receive the first part of the radiation diverted from the optical path by the reflector array and to dissipate an energy associated with said first part of the radiation.

3. The device of claim 1 further comprising:

a warning indicator configured to provide a visual cue indicating that an unsafe level of radiation is detected.

4. The device of claim 1 wherein the reflector array comprises microminiature mirrors, and wherein a first plurality of the microminiature mirrors is moved in response to the control signal such that at least some of the first part of the radiation is diverted away from the optical path.

5. The device of claim 1 wherein the control signal is operative to cause the reflector array to divert substantially all of the first part of the radiation away from the optical path if the level of radiation is detected as exceeding a threshold value.

6. The device of claim 5 wherein the threshold value is established in accordance with a maximum permissible exposure level of the ANSI Z136 standard for eye safety.

7. The device of claim 1 wherein the reflector array adjusts the first part of the radiation such that radiation exiting the housing via the second aperture does not exceed a threshold value in response to the control signal.

8. The device of claim 1 wherein the photodetector detects the level of the second part of the radiation without interruption due to operation of the reflector array.

9. The device of claim 8 wherein the control signal is operative to vary an amount of the first part of the radiation diverted from the optical path in accordance with a maximum permissible exposure level for eye safety.

10. The device of claim 1 wherein the control circuit further comprises an integrator for integrating the output of the photodetector, and wherein the control signal varies according to an amount of radiation entering the housing during a predetermined time interval.

11. The device of claim 1 further comprising a wavelength selective filter configured to pass first wavelengths of the radiation to the photodetector, and wherein the output of the photodetector corresponds to a level of said first wavelengths.

12. The device of claim 11 wherein the first wavelengths of the radiation includes wavelengths in the range of about 400 nm to about 700 nm.

13. The device of claim 11 wherein the first wavelengths of the radiation includes wavelengths greater than approximately 700 nm.

14. The device of claim 1 wherein the reflector array comprises a micro-electro-mechanical mirror array.

15. A method of protecting against harmful levels of radiation at a receiver having a housing with first and second apertures, the method comprising:

receiving radiation into the housing through the first aperture;

dividing the radiation into a first part and a second part;

directing the second part of the radiation to a detector;

detecting a level of the second part of the radiation at the detector;

generating a drive signal based upon the level of the radiation at the detector; and

selectively diverting the first part of the radiation from an optical path extending to the second aperture in response to the drive signal, wherein the second part of the radiation is available at the detector when the first part of the radiation is diverted from the optical path.

16. The method of claim 15 further comprising:

providing a warning indicator to signal that an unsafe level of radiation is detected.

17. The method of claim 15 wherein selectively diverting the first part of the radiation comprises moving a plurality of the reflectors in response to the drive signal.

18. The method of claim 15 wherein selectively diverting the first part of the radiation comprises diverting substantially all of the radiation away from the optical path if the level of the radiation exceeds a predetermined value.

19. The method of claim 18 wherein the predetermined value is established in accordance with a maximum permissible exposure level of the ANSI Z136 standard for eye safety.

20. The method of claim 15 further comprising:

automatically adjusting an amount of the radiation diverted from the optical path based on a maximum permissible exposure level for eye safety; and

detecting without interruption the level of the second part of the radiation while the amount of the radiation diverted from the optical path is adjusted.

21. The method of claim 15 wherein generating the drive signal comprises integrating a signal representative of the level of the radiation at the detector, and wherein the drive signal varies according to an amount of radiation entering the housing during a predetermined time interval.

22. The method of claim 15 wherein detecting a level of the radiation at the detector further comprises filtering the radiation by wavelength and detecting an irradiance of the filtered radiation.

23. The method of claim 22 wherein the filtered radiation comprises wavelengths in the range from about 400 nm to about 700 nm.

24. The method of claim 22 wherein the filtered radiation comprises wavelengths greater than approximately 700 nm.

25. A laser safety device comprising:

a housing having first and second apertures;

a beam splitter optically coupled to the first aperture and configured to divide radiation entering the housing into a first part and a second part;

a photodetector optically coupled to the second part of the radiation and configured to generate one or more first signals corresponding to a level of the second part of the radiation;

a memory configured to store eye safety information corresponding to wavelengths of the radiation that are detected by the photodetector;

a control circuit configured to receive the one or more first signals and to generate second signals indicative of whether the level of the second part of the radiation exceeds a threshold value determined in accordance with the eye safety information;

a warning indicator configured to receive select ones of the one or more second signals and to provide a visual cue if the first wavelengths exceed the eye-safe threshold; and

a micro-electro-mechanical mirror array configured to direct the first part of the radiation away from an optical path extending to the second aperture in response to an indication from the second signals that the second part of the radiation exceeds the threshold value,

wherein the beam splitter is configured to direct the second part of the radiation to the photodetector without interruption when the micro-electro-mechanical mirror array directs the first part of the radiation from the optical path.