A luminance adjusting algorithm for high resolution and high image quality AMOLED displays of mobile phone applications

Symp Digest of Tech Papers

2013

Self Cite

An active matrix organic light emitting diode (AMOLED) pixel structure is proposed to improve image quality of high resolution small sized displays. The proposed pixel structure increases luminance uniformity by decreasing the distortion of the voltage in the storage capacitors using negative feedback structure. The simulation results show that the distortion of the voltage in the storage capacitors with negative feedback structure decreases to 55.3% compared to that without negative feedback structure and the emission current error of the proposed pixel structure ranges from -0.71 LSB to 0.56 LSB when the threshold voltage of the driving TFT varies from -0.2 V to 0.2 V.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

35.1: High Resolution AMOLED Pixel Using Negative Feedback Structure for Improving Image Quality

Symp Digest of Tech Papers

2013

Self Cite

“…The electrical characteristic variations of poly‐crystalline silicon (poly‐Si) thin‐film transistors (TFTs) are the main problem that causes nonuniform luminance of active matrix organic light‐emitting diode (AMOLED) displays . In order to improve the luminance uniformity of the AMOLED displays, various methods for compensating the threshold voltage variations of poly‐Si TFTs are proposed . Voltage programming with diode connection of driving TFTs is one of the methods for compensating the threshold voltage variations of poly‐Si TFTs .…”

Section: Introductionmentioning

confidence: 99%

Pixel structures using the negative feedback method for high‐resolution active matrix organic light‐emitting diode displays

2013

J Soc Info Display

Self Cite

-Novel two pixel structures are proposed for high-resolution active matrix organic lightemitting diode displays. The proposed two pixels (pixel structures A and B) use the negative feedback method for high-resolution displays that requires to have small-sized storage capacitance. The proposed pixel structures A and B improve the luminance uniformity by reducing the voltage distortion in the storage capacitor. However, the proposed pixel structure A is vulnerable to the organic light-emitting diode (OLED) degradation because the anode voltage of the OLED affects the emission current. In order to compensate the OLED degradation, the proposed pixel structure B stores the turn-on voltage of OLEDs in the storage capacitor. The simulation results show that the emission current error of the proposed pixel structure B is improved by four times in comparison with the proposed pixel structure A when the OLED turn-on voltage increases by 0.1 V. Also, the emission current error of the proposed pixel structure B when the threshold voltage of driving thin-film transistors varies from À2.2 to À1.8 V is from À0.69 least significant bit (LSB) to 0.13 LSB, which shows the excellent luminance uniformity. The proposed pixels are designed for 5.5-in. full high-definition displays.

“…Previously, pixel structures and driving methods to compensate electrical variation of driving TFTs have been reported [2][3][4], but compensation capability is reduced as the display resolution is increased because the row line time which is used for compensation phase is reduced as the resolution of panel is increased. To solve the problem of limited compensation time, the parameter extraction and data adjusting method using light sensor have been proposed [5]. This method assumed that the relation of luminance and data voltage of AMOLED pixel is quadratic [5], however drain current of driving TFT is not quadratic function thus luminance error will be increased due to the large difference between modeling and real characteristic in low gray levels.…”

Section: Introductionmentioning

confidence: 99%

“…To solve the problem of limited compensation time, the parameter extraction and data adjusting method using light sensor have been proposed [5]. This method assumed that the relation of luminance and data voltage of AMOLED pixel is quadratic [5], however drain current of driving TFT is not quadratic function thus luminance error will be increased due to the large difference between modeling and real characteristic in low gray levels.…”

Section: Introductionmentioning

confidence: 99%

Memory reduction method of luminance compensation algorithm for mobile AMOLED display applications

2013 IEEE International Conference on Consumer Electronics (ICCE)

2013

A memory reduction method of luminance compensation algorithm using luminance sensor is proposed for high resolution mobile active matrix organic light emitting diode (AMOLED) display applications. The proposed method can be applied to AMOLED panels which have poor luminance uniformity even though compensation pixel circuit is used. Measurement results show that the deviation of luminance error is reduced from 18.1% to 3.8% when the proposed algorithm is applied to 5.3-inch AMOLED panel using threshold voltage compensation pixel structure.