Intelligent light source with synchronization with a digital camera
View Patent ↗An intelligent light source for use with the test of a digital camera module provides a plurality of shapes of light. A fast light pulse is created with turn-on and turn-off transitions less than or equal to one microsecond. Other waveform shapes comprise a ramp and a sinusoid, and all shapes can be made to occur once or repetitively. The magnitude of the light has a range from 0.01 LUX to 1000 LUX, and the ramp has a ramp time that has a range from microseconds to 100 ms. The light comprises of a plurality of colors created by serial connected strings of LED devices, where the LED devices in a string emit the same color. The light emanating from the light source is calibrated using a photo diode and the control of a tester by adjusting offset voltages of a DAC controlling a current through the LED strings.
1. A light system for testing a light sensitive device, comprising:
a) a tester,
b) a controller,
c) a data memory,
d) a digital to analog converter (DAC),
e) a voltage to current converter,
f) a light pulse source, comprising,
i) selectable colors comprising red, blue, green and infrared;
ii) rapid turn-on and turn-off transition of said light pulse source in the order of magnitude of one microsecond;
iii) a plurality of light pulse shapes, comprising a ramp of variable length of time and sinusoidal varying light;
iv) a plurality of light intensity;
g) a light sensitive device under test (DUT) synchronized with said light pulse source,
h) said tester coupled to the controller to control a selection of test data from said data memory to be coupled to said DAC,
i) said DAC controlling said voltage to current converter to produce a current to turn on said light pulse source to illuminate said DUT, and,
j) said DUT coupling data and control signals to said tester.
2. The light system of claim 1 , wherein said tester controls the timed occurrence of a light from said light source with a frame grabber function that synchronizes said light pulse source with a clock of said DUT.
3. The light system of claim 1 , wherein said controller controls the repetitive occurrence of a light from said light pulse source.
4. The light system of claim 1 , said data memory contains data to determine an output voltage of the DAC.
5. The light system of claim 4 , wherein said voltage to current converter translates the output voltage from the DAC into a current coupled to said light pulse source.
6. The light system of claim 5 further comprising a range switch within the voltage to current converter to select a range of current to be coupled to said light pulse source.
7. The light system of claim 6 , wherein said range switch creates a plurality of current ranges to illuminate said DUT with a magnitude of light from approximately 0.01 LUX to approximately 1000 LUX.
8. The light system of claim 5 , wherein said voltage to current converter turns on and off said light pulse source comprising a rise time and a fall time equal to or less than one microsecond.
9. The light system of claim 8 , wherein said rise time of said light pulse source is a ramp with a ramp time ranging from approximately ten micro seconds to one hundred milliseconds in four discrete ranges of time.
10. The light system of claim 8 , wherein said light pulse source is in the form of a sinusoid where a stepped output of the voltage to current converter approximates a shape of a sine wave.
11. The light system of claim 1 , wherein said light sensitive device is a digital camera module under test (MUT).
12. The light system of claim 11 , wherein said data and control signals coupled to said tester from the MUT comprise a clock, a horizontal sync signal, a vertical sync signal, and picture data of an image.