Source driver and display device including the same

Abstract

A source driver capable of accurately sensing pixel characteristics and characteristics of a source driver and a display device including the same. The source driver includes: a switching circuit configured to transmit a first pixel signal or a reference signal; a first sensing channel configured to sense and hold the first pixel signal or the reference signal transmitted from the switching circuit; a second sensing channel configured to sense and hold the second pixel signal; and a selection circuit configured to output a sampling signal by selecting a first pixel signal of the first sensing channel and a second pixel signal of the second sensing channel, and thereafter, output the sampling signal by selecting a reference signal of the first sensing channel.

Description

Technical Field

[0001] Various embodiments generally relate to a display device, and more particularly, to a source driver capable of accurately sensing pixel characteristics and source driver characteristics, and a display device including the same. Background Art

[0002] Typically, a display device includes a display panel, a source driver, and a timing controller.

[0003] The source driver converts the image data provided from the timing controller into a source signal and provides the source signal to the display panel to display an image on the display panel. Such a source driver may be integrated into one chip or may be configured from multiple chips in consideration of the size and resolution of the display panel.

[0004] In order to sense pixel characteristics of pixels of the display panel, the source driver senses pixel signals of the pixels by using a pixel sensing channel, converts the pixel signals into digital data, and provides the digital data to the timing controller.

[0005] However, the digital data includes not only pixel characteristics but also characteristics of the source driver.

[0006] In conventional technology, in order to compensate for the characteristics of the source driver, the characteristics of the source driver are sensed by using an additional sensing channel. Without the additional sensing channel, since the time of sensing the pixel and the time of sensing the characteristics of the source driver are different from each other and the temperature of the chip changes over time, it is difficult to accurately obtain the characteristics of the source driver at the actual pixel sensing time.

[0007] In the conventional technology, there is a problem that the chip area of ​​the source driver increases due to the use of an additional sensing channel, and there is a problem that the characteristics of the source driver cannot be accurately obtained due to a mismatch between a pixel sensing channel and the additional sensing channel.

[0008] That is, the conventional technology has a problem in that the characteristics of the source driver depending on the temperature cannot be accurately compensated on the image data. Summary of the invention

[0009] Various embodiments relate to a source driver capable of accurately sensing pixel characteristics and characteristics of the source driver and a display device including the same.

[0010] In an embodiment, a source driver may include: a switching circuit configured to transmit a first pixel signal or a reference signal; a first sensing channel configured to sense and hold the first pixel signal or the reference signal transmitted from the switching circuit; a second sensing channel configured to sense and hold the second pixel signal; and a selection circuit configured to output a sampling signal by selecting a first pixel signal of the first sensing channel and a second pixel signal of the second sensing channel, and thereafter, output the sampling signal by selecting a reference signal of the first sensing channel; wherein, after starting to convert the sampling signals corresponding to the first pixel signal and the second pixel signal into digital data, the switching circuit transmits the reference signal to the first sensing channel.

[0011] In an embodiment, a display device may include: a display panel; and a source driver connected to the display panel through a sensing line; wherein the source driver senses a first pixel signal and a second pixel signal transmitted through the sensing line and converts the first pixel signal and the second pixel signal into digital data, senses a reference signal transmitted through the sensing line after starting to convert the first pixel signal and the second pixel signal into digital data, and converts the reference signal into digital data after the first pixel signal and the second pixel signal are converted into digital data.

[0012] As described above, since the embodiment senses not only pixel characteristics but also characteristics of the source driver by using a sensing channel for sensing pixel characteristics, it is possible to accurately compensate for changes in the characteristics of the source driver due to temperature on image data.

[0013] In addition, since the embodiment does not require an additional sensing channel for sensing the characteristics of the source driver, the chip area of ​​the source driver can be reduced.

[0014] Furthermore, embodiments may eliminate mismatches between pixel sensing channels and channels used to sense characteristics of source drivers. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a block diagram of a display device according to an embodiment.

[0016] Figure 2 is a block diagram of a source driver according to an embodiment.

[0017] Figure 3 is a timing diagram of a source driver according to an embodiment. DETAILED DESCRIPTION

[0018] The source driver embodied in the present disclosure and the display device including the same may be configured to accurately sense a characteristic change of the source driver depending on temperature by using a pixel sensing channel.

[0019] In an embodiment, the characteristics of the source driver may be defined to include characteristics of a sensing channel and characteristics of an analog-to-digital converter that vary according to the temperature of a chip or external factors. For example, offset and gain may be exemplified as characteristics of a sensing channel and an analog-to-digital converter.

[0020] In an embodiment, the display period may be defined as a period in which a source signal corresponding to image data is provided to the display panel, and the sensing period may be defined as a period in which pixel characteristics are detected by sensing pixel signals from pixels of the display panel.

[0021] Embodiments may operate in an initialization mode, a programming mode, and a sensing mode. The initialization mode may be defined as an operation of initializing pixels, the programming mode may be defined as an operation of programming pixels with reference signals after the initialization mode, and the sensing mode may be defined as an operation of sensing pixel characteristics and source driver characteristics after the programming mode.

[0022] Figure 1 is a block diagram of a display device including a source driver according to an embodiment.

[0023] Reference Figure 1 , the display device includes a display panel 100 and a source driver 200 .

[0024] The display panel 100 includes data lines (not shown) and gate lines (not shown), and includes pixels formed at intersections of the data lines and the gate lines. For example, the display panel 100 may implement pixels by using organic light emitting diodes (OLEDs). Each of the pixels may include an organic light emitting diode and a driving transistor.

[0025] The characteristics of the driving transistor and the organic light emitting diode, such as threshold voltage and mobility, may be different from pixel to pixel. When the characteristics of the driving transistor are different from pixel to pixel, the currents flowing through the driving transistors of the corresponding pixels may be different from each other even when the same source signal is applied to the corresponding pixels.

[0026] In addition, the organic light emitting diode and the driving transistor of each pixel may be degraded as the driving time passes, thereby causing a brightness deviation between pixels and thus causing a brightness non-uniformity phenomenon.

[0027] The above threshold voltage, mobility and degradation of the driving transistor and the organic light emitting diode of each pixel can be understood as pixel characteristics. Deviations in such pixel characteristics between pixels can be solved by compensating for values ​​corresponding to the pixel characteristics on the image data.

[0028] To this end, the source driver 200 is configured to sense pixel signals P1 to Pn from the pixels of the display panel 100 to detect pixel characteristics. The source driver 200 and the display panel 100 may be connected to each other through sensing lines SL1 to SLn that transmit the pixel signals P1 to Pn. For example, depending on the type of pixel, the sensing lines SL1 to SLn may be connected to the data lines of the display panel 100, or to the detection lines (not shown) in the display panel 100.

[0029] Through the above description, the source driver 200 may sense the pixel signals P1 to Pn corresponding to the pixel characteristics of the corresponding pixels of the display panel 100 through the sensing lines SL1 to SLn.

[0030] In addition, the source driver 200 may be configured to sense reference signals REF1 to REFm by using some of the sensing lines SL1 to SLm among the sensing lines SL1 to SLn. The reference signals REF1 to REFm may be understood as reference voltages for detecting characteristics of the source driver 200.

[0031] In order to compensate for pixel characteristics on image data, the source driver 200 can sense pixel signals P1 to Pn corresponding to pixel characteristics of corresponding pixels transmitted from sensing lines SL1 to SLn from the display panel 100, can convert sampling signals SAM corresponding to the pixel signals P1 to Pn into digital data DOUT, and can provide the digital data DOUT to a timing controller (not shown).

[0032] For example, the pixel signals P1 to Pn can be used to calculate the degradation characteristics of the pixel such as the threshold voltage and mobility of each driving transistor and the threshold voltage of each organic light emitting diode. Since the pixel current flowing through the organic light emitting diode varies according to the threshold voltage and mobility of the driving transistor and the threshold voltage of the organic light emitting diode, the pixel current can be used to calculate the value of the above-mentioned pixel characteristics of each pixel. The value of the pixel characteristic of each pixel can be used to compensate the image data.

[0033] During a sensing period for detecting pixel characteristics of the display panel 100 , the source driver 200 may detect characteristics of the source driver 200 by sensing the reference signals REF1 to REFm and the pixel signals P1 to Pn.

[0034] To this end, during a sensing period after detecting pixel characteristics of a pixel of the display panel 100, the source driver 200 may perform sensing of reference signals REF1 to REFm, converting a sampling signal SAM corresponding to the reference signals REF1 to REFm into digital data DOUT, and providing the digital data DOUT to a timing controller to compensate for characteristics such as offset and gain on image data of the source driver 200.

[0035] For example, the characteristics of the source driver 200 including the offset and the gain may change according to the temperature of the chip or external factors. In order to compensate the characteristics of the source driver 200 in real time, after converting the sampling signal SAM corresponding to the pixel signals P1 to Pm into the digital data DOUT and outputting the digital data DOUT, the source driver 200 may sense the reference signals REF1 to REFm transmitted through the sensing lines SL1 to SLm.

[0036] To this end, the source driver 200 may sense reference signals REF1 to REFm transmitted through some sensing lines after starting to convert sampling signals SAM corresponding to pixel signals P1 to Pn into digital data DOUT, may convert sampling signals SAM corresponding to reference signals REF1 to REFm into digital data DOUT after converting the sampling signals SAM corresponding to pixel signals P1 to Pn into digital data DOUT, and may provide the digital data DOUT to the timing controller.

[0037] The timing controller may receive the digital data DOUT in real time, may calculate the pixel characteristics and the characteristics of the source driver 200 in real time by using the digital data DOUT, and may compensate for the pixel characteristics and the characteristics of the source driver 200 on the image data.

[0038] A display device including the above-mentioned source driver 200 can detect the characteristics of the source driver 200 together during a sensing period of detecting pixel characteristics of a pixel, thereby accurately detecting the characteristics of the source driver 200 that vary according to temperature and external factors in real time and accurately compensating image data.

[0039] The source driver 200 may include a sensing circuit 10 and an analog-to-digital converter 20. The sensing circuit 10 may include a plurality of sensing channels. It is understood that the plurality of sensing channels correspond to the sensing lines SL1 to SLn. The sensing circuit 10 may sense pixel signals P1 to Pm or reference signals REF1 to REFm by using some of the plurality of sensing channels, and may sense pixel signals Pm+1 to Pn by using the remaining sensing channels.

[0040] The sensing circuit 10 may provide the sampling signal SAM corresponding to the pixel signals P1 to Pn or the reference signals REF1 to REFm to the analog-to-digital converter 20 in a preset order. For example, the sensing circuit 10 may provide the sampling signal SAM corresponding to the pixel signals P1 to Pn to the analog-to-digital converter 20, and then may provide the sampling signal SAM corresponding to the reference signals REF1 to REFm to the analog-to-digital converter 20.

[0041] The analog-to-digital converter 20 can convert the sampling signal SAM corresponding to the pixel signals P1 to Pn into digital data DOUT and output the digital data DOUT to the timing controller, and then can convert the sampling signal SAM corresponding to the reference signals REF1 to REFm into digital data DOUT and output the digital data DOUT to the timing controller.

[0042] Figure 2 is a block diagram of a source driver 200 according to an embodiment.

[0043] Reference Figure 2 The source driver 200 may include a switch circuit 30 , a sensing circuit 10 , and an analog-to-digital converter 20 , and the sensing circuit 10 may include a first sensing channel 12 , a second sensing channel 14 , and a selection circuit 16 .

[0044] The switch circuit 30 may be configured to transfer the first pixel signals P1 to Pm or the reference signals REF1 to REFm to the first sensing channel 12 through the sensing lines SL1 to SLm.

[0045] The switch circuit 30 may transmit the first pixel signals P1 to Pm to the first sensing channel 12 during a sensing period for detecting pixel characteristics, and may transmit the reference signals REF1 to REFm to the first sensing channel 12 during a partial period of the sensing period. The partial period may be set to a partial period after the sampling signal SAM corresponding to the first pixel signals P1 to Pm is converted into the digital data DOUT during the sensing period for detecting pixel characteristics.

[0046] The first sensing channel 12 can sense and hold the first pixel signals P1 to Pm or the reference signals REF1 to REFm transmitted from the switch circuit 30 through the sensing lines SL1 to SLm. The second sensing channel 14 can sense and hold the second pixel signals Pm+1 to Pn transmitted through the sensing lines SLm+1 to SLn. For example, each of the first sensing channel 12 and the second sensing channel 14 may include a sampling and holding circuit. Generally, the sampling and holding circuit may include a sampling switch SW for sampling an input signal and a sampling capacitor C for holding the sampled signal.

[0047] The sensing of the first pixel signals P1 to Pm by the first sensing channel 12 and the sensing of the second pixel signals Pm+1 to Pn by the second sensing channel 14 may be sequentially performed within the same sensing period. In other words, within the same sensing period, the first sensing channel 12 and the second sensing channel 14 may sequentially sense and hold the pixel signals P1 to Pn of the display panel 100.

[0048] The selection circuit 16 may sequentially select the first pixel signals P1 to Pm or the reference signals REF1 to REFm held in the first sensing channel 12 as the sampling signals SAM, and may output the sampling signals SAM to the analog-to-digital converter 20. In addition, the selection circuit 16 may select the second pixel signals Pm+1 to Pn held in the second sensing channel 14 as the sampling signals SAM, and may sequentially output the sampling signals SAM to the analog-to-digital converter 20.

[0049] After transmitting the sampling signals SAM corresponding to the first pixel signals P1 to Pm and the second pixel signals Pm+1 to Pn to the analog-to-digital converter 20 , the switch circuit 30 may transmit the reference signals REF1 to REFm to the first sensing channel 12 during the sensing period.

[0050] The first and second sensing channels 12 and 14 may be connected to the display panel 100 through the sensing lines SL1 to SLn. The switch circuit 30 may transmit the reference signals REF1 to REFm to the first sensing channel 12 through some of the sensing lines SL1 to SLm among the sensing lines SL1 to SLn.

[0051] The analog-to-digital converter 20 may convert the sampling signal SAM output from the selection circuit 16 into digital data DOUT, and may output the digital data DOUT to the timing controller. In this regard, after the analog-to-digital converter 20 starts converting the sampling signal SAM corresponding to the first pixel signals P1 to Pm and the second pixel signals Pm+1 to Pn into digital data DOUT, the switch circuit 30 may transmit the reference signals REF1 to REFm to the first sensing channel 12.

[0052] The analog-to-digital converter 20 may convert the sampling signal SAM into digital data DOUT in the order of the first pixel signals P1 to Pm, the second pixel signals Pm+1 to Pn, and the reference signals REF1 to REFm.

[0053] Through the above-described embodiments of the present disclosure, the first sensing channel 12 may detect pixel characteristics from the display panel 100 during a sensing period, and may sense reference signals REF1 to REFm for detecting characteristics of the source driver 200 during a second sensing period belonging to the sensing period.

[0054] Figure 3 2 is a timing chart of the source driver 200 according to the present embodiment.

[0055] Embodiments may operate in a sensing mode, where during a sensing period, pixel characteristics of the display panel 100 are detected and characteristics of the source driver 200 are detected.

[0056] For example, the embodiment may be operated by being divided into an initialization mode, a programming mode, and a sensing mode. The initialization mode may be defined as an operation of initializing pixels, the programming mode may be defined as an operation of programming pixels with reference signals after the initialization mode, and the sensing mode may be defined as an operation of sensing pixel characteristics and characteristics of the source driver 200 after the programming mode.

[0057] Figure 3 The operation of the source driver 200 in the sensing mode following the programming mode is shown, in which the pixel characteristics and the characteristics of the source driver 200 are sensed. A period during which the sensing mode is maintained may be understood as a sensing period.

[0058] Reference Figures 1 to 3 , the source driver 200 may sense pixel signals P1 to Pn corresponding to pixel characteristics of corresponding pixels of the display panel 100 through the sensing lines SL1 to SLn, and may sense reference signals REF1 to REFm by using some of the sensing lines SL1 to SLm among the sensing lines SL1 to SLn.

[0059] The source driver 200 may sense pixel signals P1 to Pn corresponding to pixel characteristics of corresponding pixels from the display panel 100 , may convert sampling signals SAM corresponding to the pixel signals P1 to Pn into digital data DOUT, and may provide the digital data DOUT to the timing controller.

[0060] In addition, in order to detect characteristics of the source driver 200 , the source driver 200 may sense reference signals REF1 to REFm, may convert sampling signals SAM corresponding to the reference signals REF1 to REFm into digital data DOUT, and may provide the digital data DOUT to the timing controller.

[0061] The source driver 200 may sense the reference signals REF1 to REFm after a predetermined time t from a time when the sampling signal SAM corresponding to the first pixel signals P1 to Pm is converted into the digital data DOUT.

[0062] The source driver 200 may convert sampling signals SAM corresponding to the pixel signals P1 to Pn into digital data DOUT, and then may convert the sampling signals SAM corresponding to the reference signals REF1 to REFm into digital data DOUT, and may output the digital data DOUT to the timing controller.

[0063] According to an embodiment of the present disclosure, during a sensing period of detecting pixel characteristics of pixels of the display panel 100 , the source driver 200 may detect characteristics of the source driver 200 by sensing the reference signals REF1 to REFm.

[0064] A display device including the above-mentioned source driver 200 according to an embodiment of the present disclosure can detect the characteristics of the source driver 200 during a period of detecting the pixel characteristics of the pixel, thereby accurately detecting the characteristics of the source driver 200 that vary according to temperature and external factors in real time, and thus accurately compensating for the pixel characteristics of the pixel on the image data in real time.

[0065] As is apparent from the above description, since the embodiment senses not only pixel characteristics but also characteristics of the source driver by using a sensing channel for sensing pixel characteristics, changes in characteristics of the source driver with temperature can be accurately compensated on image data.

[0066] In addition, since the embodiment does not require an additional sensing channel for sensing the characteristics of the source driver, the chip area of ​​the source driver can be reduced.

[0067] Furthermore, embodiments may eliminate mismatches between pixel sensing channels and channels used to sense characteristics of source drivers.

Claims

1. Source driver, including: a switch circuit configured to transmit a first pixel signal or a reference signal; a first sensing channel configured to sense and hold the first pixel signal or the reference signal transmitted from the switching circuit; a second sensing channel configured to sense and hold a second pixel signal; as well as a selection circuit configured to output a sampling signal by selecting the first pixel signal of the first sensing channel and the second pixel signal of the second sensing channel, and thereafter, output the sampling signal by selecting the reference signal of the first sensing channel; wherein, after starting to convert the sampling signals corresponding to the first pixel signal and the second pixel signal into digital data, the switch circuit transmits the reference signal to the first sensing channel, During a sensing period of detecting pixel characteristics from a display panel and converting the sampling signal into the digital data, the first sensing channel senses the reference signal for detecting characteristics of the source driver.

2. The source driver according to claim 1, wherein: The first sensing channel and the second sensing channel are connected to the display panel through a plurality of sensing lines, and The switch circuit selectively transmits the first pixel signal and the reference signal to the first sensing channel through some sensing lines among the plurality of sensing lines.

3. The source driver according to claim 1, further comprising: An analog-to-digital converter is configured to convert the sampling signal output from the selection circuit into the digital data.

4. The source driver according to claim 3, wherein: After the analog-to-digital converter starts converting the sampling signals corresponding to the first pixel signal and the second pixel signal into the digital data, the switch circuit transmits the reference signal to the first sensing channel.

5. The source driver according to claim 4, wherein: The analog-to-digital converter converts the sampling signal provided in the order of the first pixel signal, the second pixel signal, and the reference signal into the digital data.

6. Display equipment, including: Display panel; as well as A source driver connected to the display panel via a plurality of sensing lines; Wherein, the source driver sensing a first pixel signal and a second pixel signal transmitted through the sensing line and converting the first pixel signal and the second pixel signal into digital data, After starting to convert the first pixel signal and the second pixel signal into the digital data, sensing a reference signal transmitted through the sensing line, and After the first pixel signal and the second pixel signal are converted into the digital data, the reference signal is converted into the digital data, wherein the source driver includes a plurality of sensing channels, and senses the reference signal by using a first sensing channel for sensing the first pixel signal among the plurality of sensing channels, During a sensing period for detecting pixel characteristics from the display panel by sensing the first pixel signal and the second pixel signal, the source driver senses the reference signal for detecting characteristics of the source driver.

7. The display device according to claim 6, wherein: The source driver comprises: a switch circuit configured to transmit the first pixel signal or the reference signal; a first sensing channel configured to sense and hold the first pixel signal or the reference signal transmitted from the switching circuit; a second sensing channel configured to sense and hold the second pixel signal; and A selection circuit is configured to output a sampling signal to be converted into the digital data by selecting the first pixel signal of the first sensing channel and the second pixel signal of the second sensing channel, and thereafter, output the sampling signal to be converted into the digital data by selecting the reference signal of the first sensing channel.

8. The display device according to claim 7, wherein: After starting to convert the sampling signals corresponding to the first pixel signal and the second pixel signal into the digital data, the switch circuit transmits the reference signal to the first sensing channel.

9. The display device according to claim 7, wherein: The switch circuit transmits the reference signal to the first sensing channel through some sensing lines among the plurality of sensing lines.

10. The display device according to claim 7, further comprising: An analog-to-digital converter is configured to convert the sampling signal output from the selection circuit into the digital data.

11. The display device according to claim 10, wherein: The analog-to-digital converter converts the sampling signals corresponding to the first pixel signal and the second pixel signal into the digital data, and thereafter, converts the sampling signal corresponding to the reference signal into the digital data.

12. The display device according to claim 11, wherein: The analog-to-digital converter converts the sampling signal into the digital data in the order of the first pixel signal, the second pixel signal, and the reference signal.

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