Feedback control system and method for operating a high-performance stabilized active-matrix emissive display

Abstract

System, device, and method for operating active-matrix emissive pixel display device. Method includes storing calibration value for pixels and gray levels displayed by pixels in memory; storing transformation in memory for transforming first representations of gray level values to second representations; receiving first gray level representations of image pixel gray level values; transforming first representations to second representations for each pixel; generating image data and control signals for driving pixels during present display frame time; generating integrated photon flux signal for pixels in display indicative of integrated photon flux during portion of present display frame time; comparing plurality of integrated photon flux signals with calibration values on pixel-by-pixel basis and generating plurality of comparison results indicating difference; and identifying deviation for each pixel and directing change in stored transformation to be applied during subsequent time. System provides a gray level logic, calibration memory, a comparator, and pixel deviation logic.

1 . A system for operating an active-matrix OLED display device having a plurality of pixels, the system comprising: 
 a gray level logic coupled to an external source of digital image data, the gray level logic including a transformation for transforming a first representation of an image pixel gray level value to a second representation of the same image gray level pixel value;    a display controller operable to receive inputs from the gray level logic and to communicate image and control signals to display matrix row select and column drive circuits, the row select and column drivers operable to cause an image to be displayed during a frame time for a plurality of pixels;    each of the plurality of pixels including a pixel photon flux emitter and a pixel photon flux receptor that integrates at least a portion of the emitted photon flux from the emitter during a portion of the pixel display frame time and generates an output signal indicative of the integrated photon flux;    a calibration memory storing a calibration value for each pixel and each pixel value that may be displayed by the pixel;    a comparator receiving the output signals from each of the plurality of pixels and the calibration memory and comparing the received output signals with a like plurality of corresponding signals from the calibration memory to compute a difference signal for each pixel; and    a pixel deviation logic receiving difference signals from the comparator and directing a change in the gray level logic transformation for at least pixel locations and pixel gray level values that have a difference between the calibration and the measured values.    
     
     
         2 . A system as in  claim 1 , wherein the pixel deviation logic includes a pixel deviation memory for storing a deviations between a calibrated pixel luminance value and a measured pixel luminance value.  
     
     
         3 . A system as in  claim 1 , wherein the calibration values are voltage values and the output signals indicative of the integrated photon flux are voltages, and the comparator is a voltage comparison circuit.  
     
     
         4 . A system as in  claim 1 , wherein the calibration values are voltage values and the output signals indicative of the integrated photon flux are voltages, and the comparator is a charge amp/impedance transformation circuit.  
     
     
         5 . A system as in  claim 1 , wherein the calibration values are voltage values and the output signals indicative of the integrated photon flux are currents, and the comparator is a voltage comparison circuit.  
     
     
         6 . A system as in  claim 1 , wherein the calibration values are voltage values and the output signals indicative of the integrated photon flux are charges, and the comparator is a voltage comparison circuit.  
     
     
         7 . A system as in  claim 1 , wherein the output signal indicative of the integrated photon flux are analog signals, and the system further comprising: 
 a sample and hold circuit for sampling an analog signal as a voltage representing a per pixel integrated photon flux during the portion of the pixel display frame time and holding that sampled signal for conversion to a digital value;    an analog to digital converter converting the sampled and held analog signals to digital values; and    a multiplexer coupled to the analog-to-digital converter and receiving digital values and communicating them to the comparator according to a predetermined format and order.    
     
     
         8 . A system as in  claim 1 , wherein the output signal indicative of the integrated photon flux are analog signals, and the system further comprising: 
 a sample and hold circuit for sampling an analog signal as a voltage representing a per pixel integrated photon flux during the portion of the pixel display frame time and holding that sampled signal;    a multiplexer coupled to the sample and hold circuit and receiving the sampled and held analog values; and    an analog to digital converter converting the sampled and held analog signals received from the multiplexer and converting the analog values to digital values and communicating them to the comparator according to a predetermined format and order.    
     
     
         9 . A system as in  claim 1 , further comprising the external source of digital image data.  
     
     
         10 . A system as in  claim 9 , wherein the external source of digital image data comprises either a source of digital image data, or the combination of an analog image data and a image analog-to-digital converter.  
     
     
         11 . A system as in  claim 1 , wherein the portion of the frame time comprises the row address time or a shorter period of time.  
     
     
         12 . A system as in  claim 1 , wherein the portion of the frame time comprises substantially the entire frame time.  
     
     
         13 . A system as in  claim 1 , wherein the portion of the frame time comprises at least 50 percent of the entire frame time.  
     
     
         14 . A system as in  claim 1 , wherein the portion of the frame time comprises at least between 90 percent and 100 percent of the entire frame time.  
     
     
         15 . A system as in  claim 1 , wherein the portion of the frame time comprises at least 1 millisecond.  
     
     
         16 . A method for operating an active-matrix display device having a plurality of pixels, the method comprising: 
 storing a calibration value for each pixel and each gray level value that may be displayed by each of the pixels in a calibration memory;    storing a transformation in a transformation memory for transforming first representations of an image pixel gray level values to second representations of the same image gray level pixel values for each pixel and each gray level that may be displayed by each of the pixels in the display;    receiving first gray level representations of image pixel gray level values for a plurality of pixels from an external source;    transforming the first gray level representations to an equivalent number of second gray level representations for each pixel in accordance with the stored transformation;    generating image data and control signals for driving pixel elements in a matrix display device during a present display frame time in accordance with the second representation of the image gray level pixel value;    generating an integrated photon flux signal for each of the plurality of pixels in the display indicative of the integrated photon flux on each of the plurality of pixels in the display during a portion of the present display frame time;    comparing the plurality of integrated photon flux signals for a commanded gray level and with the calibration values for the same gray level for each pixel on a pixel-by-pixel basis and generating a plurality of comparison results indicating a difference between the commanded gray level and the measured gray level; and    identifying any deviation for each pixel based on the comparison results and directing a change in the stored transformation to be applied during a subsequent display frame time for at least pixel locations and pixel gray level values that have a difference between the calibration and the measured values.    
     
     
         17 . A method as in  claim 16 , wherein the step of identifying any deviation includes storing pixel deviations between a calibrated pixel luminance value and a measured pixel luminance value in a pixel deviation memory.  
     
     
         18 . A method as in  claim 16 , wherein the calibration values are voltage values and the integrated photon flux values are voltages, and the comparison includes a comparison of voltages.  
     
     
         19 . A method as in  claim 16 , wherein the calibration values are current values and the integrated photon flux values are currents, and the comparison includes a comparison of currents.  
     
     
         20 . A method as in  claim 16 , wherein the calibration values are charge values and the integrated photon flux values are charges, and the comparison includes a comparison of charges.  
     
     
         21 . A method as in  claim 16 , wherein the integrated photon flux values are analog signals, and the method further comprising: 
 sampling an analog signal as a voltage representing a per pixel integrated photon flux during the portion of the pixel display frame time and holding that sampled signal for conversion to a digital value; and    converting the analog sampled signal to a digital signal.    
     
     
         22 . A method as in  claim 16 , wherein the integrated photon flux values are analog signals, and the method further comprising: 
 sampling an analog signal as a charge representing a per pixel integrated photon flux during the portion of the pixel display frame time and holding that sampled signal for conversion to a digital value; and    converting the analog sampled signal to a digital signal.    
     
     
         23 . A method as in  claim 16 , wherein the integrated photon flux values are analog signals, and the method further comprising: 
 sampling an analog signal as a current representing a per pixel integrated photon flux during the portion of the pixel display frame time and holding that sampled signal for conversion to a digital value; and    converting the analog sampled signal to a digital signal.    
     
     
         24 . A method as in  claim 16 , further comprising generating the first gray level representations of image pixel gray level values for a plurality of pixels.  
     
     
         25 . A method as in  claim 24 , wherein the digital image data comprises either a digital image data, or an analog image data that is converted to a digital data by an image analog-to-digital converter.  
     
     
         26 . A method as in  claim 16 , wherein the portion of the frame time comprises a time less than or equal to the row address time.  
     
     
         27 . A method as in  claim 16 , wherein the portion of the frame time comprises substantially the entire frame time.  
     
     
         28 . A method as in  claim 16 , wherein the portion of the frame time comprises at least 50 percent of the entire frame time.  
     
     
         29 . A method as in  claim 16 , wherein the portion of the frame time comprises at least between 90 percent and 100 percent of the entire frame time.  
     
     
         30 . A method as in  claim 16 , wherein the portion of the frame time comprises at least 1 millisecond.  
     
     
         31 . A method as in  claim 16 , wherein the subsequent display frame time is the next display time following the present display frame time.  
     
     
         32 . A method as in  claim 16 , wherein the subsequent display frame time is any display frame time following the present display frame time.  
     
     
         33 . A method as in  claim 16 , wherein the subsequent display frame time is a frame time at display initialization or power-on.  
     
     
         34 . A method as in  claim 16 , wherein the image data and control signals include display matrix row and column control and drive signals operable to cause an image to be displayed during a frame time for a plurality of pixels.  
     
     
         35 . A method as in  claim 16 , wherein the pixels include at least one thin film transistor constructed from amorphous silicon.  
     
     
         36 . A method as in  claim 16 , wherein the pixels include at least one thin film transistor constructed from polysilicon.  
     
     
         37 . A method as in  claim 16 , wherein the pixels include at least one thin film transistor constructed from cadmium selenide.  
     
     
         38 . A method as in  claim 16 , wherein the pixels include at least one thin film transistor constructed from semiconductor material.  
     
     
         39 . A method as in  claim 16 , wherein the portion of the present display frame time is equal to or less than the row address time.  
     
     
         40 . A method as in  claim 16 , wherein the portion of the present display frame time is equal to or less than the frame time.  
     
     
         41 . A method as in  claim 16 , wherein the portion of the present display frame time is equal to multiple frame times.  
     
     
         42 . A method as in  claim 16 , wherein the display device is an organic light emitting diode (OLED) pixel display device.  
     
     
         43 . A method as in  claim 42 , wherein the organic light emitting diode (OLED) is a small molecule OLED.  
     
     
         44 . A method as in  claim 42 , wherein the organic light emitting diode (OLED) is a polymer OLED (PLED).  
     
     
         45 . A method as in  claim 42 , wherein the organic light emitting diode (OLED) is a phosphorescent OLED (PHOLED).  
     
     
         46 . A method as in  claim 42 , wherein the organic light emitting diode (OLED) is constructed from any organic material in any combination of single or multiple layers of organic materials and electrodes.  
     
     
         47 . A method as in  claim 42 , wherein the organic light emitting diode (OLED) is a active matrix OLED.  
     
     
         48 . A method as in  claim 16 , wherein the display device is an electroluminescent device.  
     
     
         49 . A method as in  claim 16 , wherein the display device is an plasma emission device.  
     
     
         50 . A method as in  claim 16 , wherein the display device is any controllable photon emissive device.  
     
     
         51 . A method as in  claim 47 , wherein the active matrix display device is constructed from amorphous silicon.  
     
     
         52 . A method as in  claim 47 , wherein the active matrix display device is constructed from poly-silicon.  
     
     
         53 . A method as in  claim 47 , wherein the active matrix display device is constructed from cadmium selenide.  
     
     
         54 . A method as in  claim 47 , wherein the active matrix display device is constructed from any type of semiconductor material.