Method and apparatus for testing light-emitting device

1. An apparatus for testing a light-emitting device comprising a plurality of light-emitting diodes, comprising:

an integrating sphere comprising an inlet port and a first exit port, wherein the light-emitting device is disposed close to the inlet port of the integrating sphere;

an image receiving device connected to the first exit port of the integrating sphere for receiving an image of the light-emitting device;

a processing unit coupled to image receiving device for determining a luminous intensity of each of the light-emitting diodes of the light-emitting device; and

a comparing unit coupled to the processing unit for comparing the luminous intensity of each of the light-emitting diodes of the light-emitting device with a pre-determined luminous intensity and determining whether each of the light-emitting diodes of the light-emitting device is defective or not.

2. The apparatus as claimed in claim 1 , wherein the image receiving device comprises a microscope.

3. The apparatus as claimed in claim 2 , further comprising an image sensor connected to the microscope for capturing the image of the light-emitting device.

4. The apparatus as claimed in claim 3 , wherein the image sensor comprises a CCD (Charge-Coupled Device) or a CMOS image sensor.

5. The apparatus as claimed in claim 1 , wherein the image receiving device further comprises a filter for filtering off light with a specific range of the wavelength emitted by the light-emitting device.

6. The apparatus as claimed in claim 1 , wherein the integrating sphere further comprises a second exit port, and the apparatus further comprises a detector connected to the second exit port for measuring optical characteristics of the light-emitting device.

7. The apparatus as claimed in claim 6 , wherein the detector is a photometer, a radiometer, a spectroradiometer, or a colorimeter.

8. The apparatus as claimed in claim 1 , further comprising a current source coupled to the light-emitting device.

9. The apparatus as claimed in claim 1 , wherein the light-emitting device is a chip comprising the plurality of light-emitting diodes monolithically integrated together.

10. The apparatus as claimed in claim 1 , wherein the plurality of light-emitting diodes is connected in series, parallel, or both series and parallel.

11. A method for testing a light-emitting device comprising a plurality of light-emitting diodes, comprising the steps of:

providing an integrating sphere comprising an inlet port and a first exit port;

disposing the light-emitting device close to the inlet port of the integrating sphere;

providing a current source to drive the light-emitting device to form an image of the light-emitting device in driven state;

providing an image receiving device to receive the image of the light-emitting device, wherein the image receiving device is connected to the first exit port of the integrating sphere;

determining a luminous intensity of each of the light-emitting diodes of the light-emitting device according to the image; and

comparing the luminous intensity of each of the light-emitting diodes of the light-emitting device with a pre-determined luminous intensity and determining whether each of the light-emitting diodes of the light-emitting device is defective or not.

12. The method as claimed in claim 11 , wherein the luminous intensity is determined according to a gray level of the image.

13. The method as claimed in claim 11 , wherein the image receiving device comprises a microscope.

14. The method as claimed in claim 13 , wherein the image receiving device is further connected an image sensor to capture the image of the light-emitting device.

15. The method as claimed in claim 11 , wherein the image receiving device further comprises a filter for filtering off light with a specific range of the wavelength emitted by the light-emitting device.

16. The method as claimed in claim 11 , further comprising providing a detector connected to a second exit port of the integrating sphere and further comprising a step of measuring optical characteristics of the light-emitting device by the detector.

17. The method as claimed in claim 16 , wherein the detector comprises a photometer, a radiometer, a spectroradiometer, or a colorimeter.

18. The method as claimed in claim 16 , wherein the step of receiving the image of the light-emitting device and the step of measuring optical characteristics of the light-emitting device are performed substantially at the same time.

19. The method as claimed in claim 11 , wherein the light-emitting device is a chip comprising the plurality of light-emitting diodes monolithically integrated together.

20. The method as claimed in claim 11 , wherein the plurality of light-emitting diodes is connected in series, parallel, or both series and parallel.