Apparatus and method for inspecting light-emitting diode dies
A method for inspecting LED dies includes the following steps. First electrodes and second electrodes of LED dies to be inspected are short-circuited via a conductive layer on an inspection substrate, or an inspection bias voltage is applied between the first electrodes and the second electrodes of the LED dies. An excitation light is irradiated on the LED dies to be inspected on the inspection substrate such that the LED dies to be inspected emit a secondary light. When the first electrodes and the second electrodes of the LED dies to be inspected are open, short-circuited, and/or subjected to the inspection bias voltage, the secondary light is captured via an optical sensor. An output of the optical sensor is received via a computer and a spectrum difference of the secondary light is calculated to determine whether the LED dies are abnormal or to classify the LED dies to be inspected.
1. An apparatus for inspecting light-emitting diode (LED) dies, suitable for inspecting a plurality of LED dies having first electrodes and second electrodes, the apparatus for inspecting the LED dies comprising:
an inspection substrate having a conductive layer, wherein the first electrodes and the second electrodes are open when the first electrodes and the second electrodes are not electrically connected via the conductive layer, the inspection substrate shorts the first electrode and the second electrode of each of the plurality of light-emitting diode dies to be inspected via the conductive layer, or the inspection substrate applies an inspection bias voltage between the first electrodes and the second electrodes of the plurality of LED dies to be inspected via the conductive layer;
a light source providing an excitation light to irradiate the plurality of LED dies to be inspected, and the plurality of LED dies to be inspected emit a secondary light after being irradiated by the excitation light;
an optical sensor capturing the secondary light when the first electrodes and the second electrodes of the plurality of LED dies to be inspected are open, short-circuited, and/or subjected to the inspection bias voltage; and
a computer electrically connected with the optical sensor to receive an output of the optical sensor.
2. The apparatus for inspecting the LED dies of claim 1 , wherein the light source and the optical sensor are disposed on a same side of the inspection substrate.
3. The apparatus for inspecting the LED dies of claim 1 , wherein the optical sensor comprises a spectrometer or an image sensor.
4. The apparatus for inspecting the LED dies of claim 1 ,
wherein the output of the optical sensor comprises a plurality of first spectra captured when the first electrodes and the second electrodes of the plurality of LED dies to be inspected are open, and a plurality of second spectra captured when the first electrodes and the second electrodes of the plurality of LED dies to be inspected are short-circuited,
wherein the computer compares a difference of the plurality of first spectra and the plurality of second spectra, and the difference of the plurality of first spectra and the plurality of second spectra comprises a difference in peak wavelength, a difference in dominant wavelength, a difference in peak wavelength intensity, or a difference in spectral intensity.
5. The apparatus for inspecting the LED dies of claim 1 ,
wherein the output of the optical sensor comprises a plurality of first spectra captured when the first electrodes and the second electrodes of the plurality of LED dies to be inspected are open, and a plurality of third spectra captured when the first electrodes and the second electrodes of the plurality of LED dies to be inspected are subjected to the inspection bias voltage,
wherein the computer compares a difference of the plurality of first spectra and the plurality of third spectra, and the difference of the plurality of first spectra and the plurality of third spectra comprises a difference in peak wavelength, a difference in dominant wavelength, a difference in peak wavelength intensity, or a difference in spectral intensity.
6. The apparatus for inspecting the LED dies of claim 1 ,
wherein the output of the optical sensor comprises a plurality of second spectra captured when the first electrodes and the second electrodes of the plurality of LED dies to be inspected are short-circuited, and a plurality of third spectra captured when the first electrodes and the second electrodes of the plurality of LED dies to be inspected are subjected to the inspection bias voltage,
wherein the computer compares a difference of the plurality of second spectra and the plurality of third spectra, and the difference of the plurality of second spectra and the plurality of third spectra comprises a difference in peak wavelength, a difference in dominant wavelength, a difference in peak wavelength intensity, or a difference in spectral intensity.
7. The apparatus for inspecting the LED dies of claim 1 ,
wherein the output of the optical sensor comprises a plurality of second spectra captured when the first electrodes and the second electrodes of the plurality of LED dies to be inspected are short-circuited,
wherein the computer compares a difference of the plurality of second spectra, and the difference of the plurality of second spectra comprises a difference in peak wavelength, a difference in dominant wavelength, a difference in peak wavelength intensity, or a difference in spectral intensity.
8. The apparatus for inspecting the LED dies of claim 1 ,
wherein the output of the optical sensor comprises a plurality of third spectra captured when the first electrodes and the second electrodes of the plurality of LED dies to be inspected are subjected to a plurality of inspection bias voltages,
wherein the computer compares a difference of the plurality of third spectra, and the difference of the plurality of third spectra comprises a difference in peak wavelength, a difference in dominant wavelength, a difference in peak wavelength intensity, or a difference in spectral intensity.
9. The apparatus for inspecting the LED dies of claim 1 ,
wherein the output of the optical sensor comprises a plurality of third spectra captured when the first electrodes and the second electrodes of the plurality of LED dies to be inspected are subjected to a same inspection bias voltage,
wherein the computer compares a difference of the plurality of third spectra, and the difference of the third spectra comprises a difference in peak wavelength, a difference in dominant wavelength, a difference in peak wavelength intensity, or a difference in spectral intensity.
10. A method for inspecting light-emitting diode (LED) dies, comprising:
providing a plurality of LED dies to be inspected, the plurality of LED dies having first electrodes and the second electrodes, wherein the first electrodes and the second electrodes are open;
shorting a first electrode and a second electrode of each of a plurality of LED dies to be inspected via a conductive layer on an inspection substrate, or applying an inspection bias voltage between the first electrodes and the second electrodes of the plurality of LED dies to be inspected via the conductive layer of the inspection substrate;
irradiating the plurality of LED dies to be inspected with an excitation light, so that the plurality of LED dies to be inspected emit a plurality of secondary light;
capturing the plurality of secondary light via an optical sensor when the first electrodes and the second electrodes of the plurality of LED dies to be inspected are open, short-circuited, and/or subjected to the inspection bias voltage; and
receiving an output of the optical sensor via a computer and calculating a spectrum difference of the plurality of secondary light to determine whether the plurality of LED dies are abnormal or to classify the plurality of LED dies to be inspected.
11. The method for inspecting the LED dies of claim 10 ,
wherein the output of the optical sensor comprises a plurality of first spectra captured when the first electrodes and the second electrodes of the plurality of LED dies to be inspected are open, and a plurality of second spectra captured when the first electrodes and the second electrodes of the plurality of LED dies to be inspected are short-circuited,
wherein the computer compares a difference of the plurality of first spectra and the plurality of second spectra, and the difference of the plurality of first spectra and the plurality of second spectra comprises a difference in peak wavelength, a difference in dominant wavelength, a difference in peak wavelength intensity, or a difference in spectral intensity.
12. The method for inspecting the LED dies of claim 10 ,
wherein the output of the optical sensor comprises a plurality of first spectra captured when the first electrodes and the second electrodes of the plurality of LED dies to be inspected are open, and a plurality of third spectra captured when the first electrodes and the second electrodes of the plurality of LED dies to be inspected are subjected to the inspection bias voltage,
wherein the computer compares a difference of the plurality of first spectra and the plurality of third spectra, and the difference of the plurality of first spectra and the plurality of third spectra comprises a difference in peak wavelength, a difference in dominant wavelength, a difference in peak wavelength intensity, or a difference in spectral intensity.
13. The method for inspecting the LED dies of claim 10 ,
wherein the output of the optical sensor comprises a plurality of second spectra captured when the first electrodes and the second electrodes of the plurality of LED dies to be inspected are short-circuited, and a plurality of third spectra captured when the first electrodes and the second electrodes of the plurality of LED dies to be inspected are subjected to the inspection bias voltage,
wherein the computer compares a difference of the plurality of second spectra and the plurality of third spectra, and the difference of the plurality of second spectra and the plurality of third spectra comprises a difference in peak wavelength, a difference in dominant wavelength, a difference in peak wavelength intensity, or a difference in spectral intensity.
14. The method for inspecting the LED dies of claim 10 ,
wherein the output of the optical sensor comprises a plurality of second spectra captured when the first electrodes and the second electrodes of the plurality of LED dies to be inspected are short-circuited,
wherein the computer compares a difference of the plurality of second spectra, and the difference of the plurality of second spectra comprises a difference in peak wavelength, a difference in dominant wavelength, a difference in peak wavelength intensity, or a difference in spectral intensity.
15. The method for inspecting the LED dies of claim 10 ,
wherein the output of the optical sensor comprises a plurality of third spectra captured when the first electrodes and the second electrodes of the plurality of LED dies to be inspected are subjected to a plurality of inspection bias voltages,
wherein the computer compares a difference of the plurality of third spectra, and the difference of the plurality of third spectra comprises a difference in peak wavelength, a difference in dominant wavelength, a difference in peak wavelength intensity, or a difference in spectral intensity.
16. The method for inspecting the LED dies of claim 10 ,
wherein the output of the optical sensor comprises a plurality of third spectra captured when the first electrodes and the second electrodes of the plurality of LED dies to be inspected are subjected to a same inspection bias voltage,
wherein the computer compares a difference of the plurality of third spectra, and the difference of the third spectra comprises a difference in peak wavelength, a difference in dominant wavelength, a difference in peak wavelength intensity, or a difference in spectral intensity.