WO2025198195A1 - Data compensation circuit and display device comprising same - Google Patents

Abstract

Disclosed are a data compensation circuit and a display device comprising same according to an embodiment of the present invention. The data compensation circuit comprises: an area determination unit for determining whether a pixel to which image data input in units of pixels is to be written is located in a predetermined compensation area within a display area; a compensation value generation unit for generating, on the basis of a grayscale value of the image data, a compensation value by using a lookup table stored in advance when the pixel to which the image data is to be written is located in the compensation area; and a data compensation unit for compensating for the image data by using the compensation value.

Description

Data compensation circuit and display device including the same

An embodiment of the present invention relates to a data compensation circuit and a display device including the same.

As the information society develops, the demand for display devices for displaying images is increasing in various forms, and recently, various types of display devices such as liquid crystal display devices (LCDs) and organic light emitting display devices (OLEDs) are being utilized.

A display device includes a display panel including a plurality of pixels, a panel driver for driving the display panel, etc. The panel driver includes a data driver for supplying a data voltage to the display panel, and a gate driver for supplying a gate signal to the display panel.

Such a display device can display an image by supplying a driving signal, such as a gate signal and a data signal, to a plurality of pixels formed on a display panel, causing the selected pixels to transmit light or directly emit light.

However, if the state of the display panel, that is, some pixels do not emit light normally, or the shape of the display panel changes so that the number of pixels emitting light in a specific area decreases, there will be areas where pixels emit light normally and areas where some pixels are removed and do not emit light.

At this time, some pixels within the display panel may be removed, making it impossible to reach the target luminance in non-emitting areas. Therefore, various methods are needed to achieve the target luminance across the entire display panel, regardless of its condition or shape.

Embodiments of the present invention can provide a data compensation circuit and a display device including the same.

The tasks of the present invention are not limited to the tasks mentioned above, and other tasks not mentioned will be clearly understood by those skilled in the art from the description below.

A data compensation circuit according to an embodiment of the present invention may include an area determination unit that determines whether a pixel into which image data input in pixel units is to be written is located in a predetermined compensation area within a display area; a compensation value generation unit that generates a compensation value using a lookup table stored in advance based on a grayscale value of the image data when the pixel into which the image data is to be written is located in the compensation area; and a data compensation unit that compensates for the image data using the compensation value.

The above-mentioned area determination unit can determine whether a pixel to be written with the input image data is located in a predetermined compensation area within the display area using a binary map in which the emission of light-emitting elements for each pixel is binarized and displayed. The compensation area may have a smaller number of pixel lines than an area in which all light-emitting elements normally emit light.

The above compensation value may include an offset value and a gain, and the lookup table may include a first lookup table in which a predetermined first reference tone value and an offset value are mapped, and a second lookup table in which a predetermined second reference tone value and a gain are mapped.

The above compensation value generation unit can estimate an offset value for a tone value of the image data by interpolating an offset value mapped to a first reference tone value of the first lookup table, and can estimate a gain for a tone value of the image data by interpolating a gain mapped to a second reference tone value of the second lookup table.

The above compensation value generation unit can estimate an offset value for the grayscale value of the image data by interpolating using a predetermined slope when the grayscale value of the image data is smaller than the smallest value or larger than the largest value among the first reference grayscale values.

The above data compensation unit can compensate for the image data by adding a value obtained by multiplying the offset value estimated from the compensation value generation unit by the gain to the input image data.

A display device according to an embodiment of the present invention may include a display panel in which pixels are arranged in an area where a plurality of gate lines and a plurality of data lines intersect; a gate driver for outputting a gate signal through the gate lines; a data driver for outputting a data voltage through the data lines; and a timing controller for controlling the gate driver and the data driver, wherein the timing controller includes a data compensation circuit for compensating for image data of an input image input from the outside, and the data compensation circuit may include an area determination unit for determining whether a pixel into which image data input in units of pixels is to be written is located in a predetermined compensation area within a display area; a compensation value generation unit for generating a compensation value using a lookup table stored in advance based on a grayscale value of the image data when the pixel into which the image data is to be written is located in the compensation area; and a data compensation unit for compensating for the image data using the compensation value.

The present invention determines a compensation area requiring luminance compensation within a display area according to the shape of a display panel, calculates a compensation value according to the grayscale value of image data written in pixels located in the compensation area using a lookup table, and applies the calculated compensation value to the image data, thereby actively compensating for luminance that varies according to the shape of the display panel.

The present invention can improve brightness uniformity in the entire area of a display panel because it performs brightness compensation for a compensation area in which the target brightness appears high within the display area.

The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

FIG. 1 is a drawing showing a display device according to an embodiment of the present invention.

Fig. 2 is a diagram showing the data compensation circuit illustrated in Fig. 1.

Figure 3 is a diagram for explaining the principle of generating a binary map.

Figures 4 to 6 are drawings for explaining the principle of determining the reference area and the compensation area.

Figures 7 to 10 are drawings for explaining the compensation value generation principle according to an embodiment of the present invention.

FIG. 11 is a diagram showing an image data compensation process according to an embodiment of the present invention.

The advantages and features of the present invention, and the methods for achieving them, will become clearer with reference to the embodiments described in detail below together with the accompanying drawings. The present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms. The embodiments are provided solely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined solely by the scope of the claims.

The shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings for explaining embodiments of the present invention are illustrative, and the present invention is not limited to the details depicted in the drawings. Throughout the specification, the same reference numerals designate substantially the same components. Furthermore, in describing the present invention, detailed descriptions of related known technologies will be omitted if they are deemed to unnecessarily obscure the gist of the present invention.

In the specification, when “comprises,” “includes,” “has,” and “consists of,” other parts may be added unless “only” is used. When a component is expressed in the singular, it may be interpreted as plural unless otherwise explicitly stated.

When interpreting a component, it is interpreted as including the error range even if there is no separate explicit description.

When the positional relationship and interconnectedness between two components are described as ‘on ~’, ‘above ~’, ‘below ~’, ‘next to ~’, ‘connect, couple’, crossing, intersecting, etc., one or more other components may be interposed between the components unless there is a mention such as ‘directly’ or ‘directly’.

When the temporal relationship is explained with phrases such as ‘after’, ‘following’, ‘next to’, or ‘before’, it may not be continuous on the time axis unless ‘right away’ or ‘directly’ is used.

To distinguish components, the ordinal numbers 1, 2, etc. may be used before the names of components; however, these ordinal numbers or names of components do not limit their function or structure. For convenience of explanation, the ordinal numbers preceding the names of the same components may differ across embodiments.

The following embodiments can be partially or fully combined or combined with one another, enabling various technically diverse interconnections and operations. Each embodiment can be implemented independently of the other, or can be implemented together in a related manner.

Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings.

FIG. 1 is a drawing showing a display device according to an embodiment of the present invention.

Referring to FIG. 1, a display device according to an embodiment of the present invention may include a display panel (110) and a display driving circuit for driving the display panel. The display driving circuit may include a gate driving unit (120), a data driving unit (130), and a timing controller (140). The display device may further include a host system (150) that supplies various timing signals to the timing controller (140).

The display panel (110) may include a plurality of gate lines (GL1 to Gn) and a plurality of data lines (DL1 to DLm) that are arranged in a cross-sectional manner to define a plurality of pixel areas, and pixels (P) that are respectively provided in the plurality of pixel areas and arranged in a matrix form. Each of the pixels (P) may be divided into a red pixel that emits red light, a green pixel that emits green light, and a blue pixel that emits blue light for color implementation, but is not limited thereto.

The gate driver (120) may be arranged on one side of the display panel (110), for example, on the left side, as shown, but may also be arranged on both one side and the other side of the display panel (110), for example, on both the left and right sides, facing each other, as needed. The gate driver (120) may include a plurality of gate driver ICs (Gate Driver Integrated Circuits, not shown).

The gate driver (120) may be formed in the form of a tape carrier package in which a gate driver IC is mounted, but is not necessarily limited thereto, and the gate driver IC may be mounted directly on the display panel (110).

The data driving unit (130) converts a digital image signal transmitted from the timing controller (140) into an analog source signal and outputs it to the display panel (110). Specifically, the data driving unit (130) outputs an analog source signal to the data lines (DL1 to DLm) in response to a data control signal (DCS: Data Control Signal) transmitted from the timing controller (140).

The data driving unit (130) may be disposed on one side of the display panel (110), for example, on the upper side, but may also be disposed on both one side and the other side of the display panel (110), for example, on both the upper and lower sides, facing each other, depending on the case. In addition, the data driving unit (130) may be formed in the form of a tape carrier package in which a source driver IC is mounted, but is not necessarily limited thereto.

The timing controller (140) can receive various timing signals including a vertical synchronization signal (Vsync), a horizontal synchronization signal (Hsync), a data enable (DE) signal, a clock signal (CLK), etc. from the host system (150) and generate a data control signal (DCS) for controlling the data driver (130) and a gate control signal (GCS) for controlling the gate driver (120). In addition, the timing controller (140) can receive image data (RGB) from the host system (150) and convert it into image data (RGB') in a form that can be processed by the data driver (130) and output it.

The data control signal (DCS) may include a source start pulse (SSP), a source sampling clock (SSC), and a source output enable signal (SOE), and the gate control signal (GCS) may include a gate start pulse (GSP), a gate shift clock (GSC), and a gate output enable signal (GOE).

The host system (150) may be implemented as any one of a navigation system, a set-top box, a DVD player, a Blu-ray player, a personal computer (PC), a home theater system, a broadcast receiver, and a phone system.

The host system (150) can include a system on chip (SoC) with a built-in scaler to convert digital image data (RGB) of an input image into a format suitable for display on a display panel (110). The host system (150) can transmit digital image data (RGB) and various timing signals to a timing controller (140).

FIG. 2 is a diagram showing the data compensation circuit illustrated in FIG. 1, FIG. 3 is a diagram explaining the principle of generating a binary map, and FIGS. 4 to 6 are diagrams explaining the principle of determining a reference area and a compensation area.

Referring to FIG. 2, a data compensation circuit (141) according to an embodiment of the present invention may include an area determination unit (141a), a compensation value generation unit (141b), an LUT storage unit (141c), and a data compensation unit (141d).

The area determination unit (141a) can determine the reference area and the compensation area within the display area using a pre-stored binary map. For example, in an embodiment as shown in FIG. 3, an inspection device such as a camera can be used to apply a driving voltage to a pixel driving circuit within the display panel to cause a light-emitting element to emit light, and then an image can be acquired, and the acquired image can be binarized to generate a binary map. In the image, a light-emitting element marked in black represents a light-emitting element in an area that has been removed as the shape of the display panel has changed. Therefore, in the binary map, a light-emitting element that normally emits light can be mapped to '1', and a light-emitting element in an area that has been removed can be mapped to '0' because it does not emit light.

Here, the binary map can be generated from an image obtained while the manufacturing process of the display panel is in progress, rather than after the manufacturing process has been completed, for example, while the pixel driving circuit is arranged on the substrate and the light emitting element is transferred on top of the pixel driving circuit.

Using a binary map, the display area can be divided into a reference area and a compensation area. The reference area may be an area where all light-emitting elements emit light normally, and the compensation area may be an area where some light-emitting elements are removed and do not emit light.

At this time, the reference area and the compensation area may vary depending on the shape of the display panel. For example, as shown in FIG. 4, the shape of the display panels (110) constituting the signage device (110') may vary depending on the overall shape of the signage device.

For example, since the display panel located at the first point (P1) of the signage device has a shape with the upper right portion removed, a reference area (A1) and a compensation area (A2) can be distinguished as in Fig. 5. Since the display panel located at the second point (P2) of the signage device has a shape with the upper portion removed, a reference area (A1) and a compensation area (A2) can be distinguished as in Fig. 6.

The compensation area (A2) may have fewer pixel lines than the normal area (A1).

At this time, since all light-emitting elements in the reference area (A1) emit light normally, the reference area (A1) is similar to the target luminance, and thus luminance compensation is not required. However, since some light-emitting elements are removed and do not emit light in the compensation area (A2), the number of light-emitting elements that emit light is smaller than in the reference area (A1), and thus the compensation area has a luminance value higher than the target luminance. Luminance compensation is required to make the luminance of the compensation area (A2) similar to the luminance of the reference area (A1). Therefore, in the embodiment, it is intended to perform luminance compensation for the compensation area within the display area.

At this time, the target brightness can be calculated using the brightness value of each light-emitting element in the reference area (A1). For example, the target brightness can be calculated as an average value of the brightness values of each light-emitting element in the reference area (A1), but is not necessarily limited thereto.

The compensation value generation unit (141b) can generate a compensation value for pixels within a compensation area based on digital image data of an input image, and provide the generated compensation value to the data compensation unit (141c). Here, the compensation value can include an offset value and a gain.

The compensation value generation unit (141b) may include a first compensation value generation unit (141b-1) and a second compensation value generation unit (141b-2). For example, the first compensation value generation unit (141b-1) may generate an offset value using a predetermined lookup table based on the grayscale values of the input image data. The second compensation value generation unit (141b-2) may generate a gain using a predetermined lookup table based on the grayscale values of the input image data.

The LUT storage unit (141c) can store a look-up table (LUT) in which predetermined reference tone values and compensation values are mapped for each pixel. The reference tone values applied to the look-up table and the compensation values mapped to the reference tone values may be tunable factors. In the embodiment, instead of creating a look-up table for all tone values, a look-up table for predetermined reference tone values is created, and interpolation is performed using the created look-up table, thereby estimating compensation values for all tone values.

At this time, the lookup table may include a first lookup table in which a first reference tone value and an offset value are mapped, and a second lookup table in which a second reference tone value and a gain are mapped. At this time, the first reference tone value and the second reference tone value may be set to the same value or different values.

The data compensation unit (141d) can generate image data with compensated brightness by applying an offset value and gain to the input pixel-by-pixel image data. The data compensation unit (141d) can provide the compensated image data for each pixel to the data driving unit.

At this time, the compensated image data (RGB') can be expressed as in the following mathematical expression 1.

[Mathematical Formula 1]

RGB' = RGB + (offset × gain)

Here, RGB is the input image data, offset is the offset value, and gain can be the gain.

Figures 7 to 10 are drawings for explaining the compensation value generation principle according to an embodiment of the present invention.

Referring to FIGS. 7 to 9, a compensation value generation unit (141b) according to an embodiment of the present invention can estimate an offset value using a first lookup table determined in advance based on the grayscale value of input pixel-by-pixel image data.

Here, the grayscale values Gray_la, Gray_lb, and Gray_lc can be preset reference grayscale values.

For example, as shown in FIG. 7, when the grayscale value of the image data is Gray_n and Gray_la < Gray_n < Gray_lb, the compensation value generation unit (141b) can estimate the offset value (offset) for the grayscale value Gray_n by interpolating the offset value (offset1) mapped to the grayscale value Gray_la and the offset value (offset2) mapped to the grayscale value Gray_lb based on the lookup table (LUT1) for the grayscale value Gray_la and the lookup table (LUT2) for the grayscale value Gray_lb.

Therefore, the offset value for the grayscale value Gray_n may be greater than the offset value (offset1) mapped to the grayscale value Gray_la and less than the offset value (offset2) mapped to the grayscale value Gray_lb.

At this time, the offset value for the grayscale value Gray_n is defined as in the following mathematical expression 2.

[Equation 2]

Here, Gray_n is a grayscale value of the input image data, lower gray is a lower reference grayscale value for performing interpolation, upper gray is an upper reference grayscale value for performing interpolation, offset _upper is an offset value mapped to the upper grayscale value, and offset _lower may be an offset value mapped to the lower grayscale value.

As another example, as shown in Fig. 8, the compensation value generation unit (141b) can estimate an offset value for the grayscale value Gray_n using a predetermined slope value '0' when the grayscale value of the image data is Gray_n and Gray_n < Gray_la or Gray_lc < Gray_n. Here, the slope value '0' means that the offset value does not change.

The compensation value generation unit (141b) can estimate the offset value for the grayscale value Gray_n as the offset value (offset1) mapped to the grayscale value Gray_la of the lookup table (LUT1) when it is smaller than the grayscale value Gray_la. The compensation value generation unit (141b) can estimate the offset value for the grayscale value Gray_n as the offset value (offset3) mapped to the grayscale value Gray_lc of the lookup table (LUT3) when it is larger than the grayscale value Gray_lc. Therefore, the offset value for the grayscale value Gray_n can be the same as the offset value (offset1) mapped to the grayscale value Gray_la or the offset value (offset3) mapped to the grayscale value Gray_lc.

As another example, as shown in Fig. 9, the compensation value generation unit (141b) can estimate an offset value for the grayscale value Gray_n using a predetermined slope value 'a' or 'b' when the grayscale value of the image data is Gray_n and Gray_n < Gray_la or Gray_lc < Gray_n. For example, the slope value 'a' can be applied when it is greater than the grayscale value Gray_lc, and the slope value 'b' can be applied when it is less than the grayscale value Gray_la.

The compensation value generation unit (141b) can estimate the offset value for the grayscale value Gray_n using the slope value 'a' when it is greater than the grayscale value Gray_lc. Therefore, the offset value for the grayscale value Gray_n may be greater than the offset value (offset3) mapped to the grayscale value Gray_lc of the lookup table (LUT3).

At this time, the offset value for the grayscale value Gray_n is defined as in the following mathematical expression 3.

[Equation 3]

The compensation value generation unit (141b) can estimate the offset value for the grayscale value Gray_n using the slope value 'b' when it is smaller than the grayscale value Gray_la. Therefore, the offset value for the grayscale value Gray_n may be smaller than the offset value (offset1) mapped to the grayscale value Gray_la of the lookup table (LUT1).

At this time, the offset value for the grayscale value Gray_n is defined as in the following mathematical expression 4.

[Equation 4]

Here, Gray_max is the maximum grayscale value, and Offset _max can be an offset value mapped to the maximum grayscale value.

At this time, the slope value 'a' and the slope value 'b' can be set to be the same or different.

Referring to FIG. 10, a compensation value generation unit (141b) according to an embodiment of the present invention can estimate a gain using a second lookup table determined in advance based on the grayscale value of input pixel-by-pixel image data.

Here, the grayscale values Gray_l1, Gray_l2, Gray_l3, and Gray_l4 can be predetermined reference grayscale values.

For example, if the grayscale value of image data is Gray_n and Gray_l1 < Gray_n < Gray_l2, the gain for the grayscale value Gray_n can be estimated by interpolating based on the gain (gain1) mapped to the grayscale value Gray_l1 and the gain (gain2) mapped to the grayscale value Gray_l2.

At this time, the gain for the grayscale value Gray_n is defined as in the following mathematical expression 5.

[Equation 5]

Here, Gray_n is the grayscale value of the input image data, lower gray is the lower grayscale value for performing interpolation, upper gray is the upper grayscale value for performing interpolation, gain _upper is the gain mapped to the upper grayscale value, and gain _lower can be the gain mapped to the lower grayscale value.

Here, the gain is estimated based on the grayscale value of the image data, but it may be a predetermined value based on the luminance measured using the inspection equipment after applying the offset value.

FIG. 11 is a diagram showing an image data compensation process according to an embodiment of the present invention.

Referring to FIG. 11, a data compensation circuit according to an embodiment of the present invention can receive image data in pixel units (S110).

The data compensation circuit can determine whether the corresponding pixel to which image data is to be written is located in the compensation area within the display area using a pre-stored binary map (S120).

The data compensation circuit can estimate the offset value and gain using a predetermined lookup table based on the grayscale value of the input image data when the corresponding pixel is located in the compensation area (S130).

For example, the data compensation circuit can estimate an offset value using a first lookup table based on the grayscale values of the image data, and can estimate a gain using a second lookup table.

On the other hand, the data compensation circuit may not perform the process of generating a compensation value because there is no need to compensate if the corresponding pixel is not located in the compensation area.

The data compensation circuit can generate image data with luminance compensated for by applying an estimated offset value and gain to the input pixel-by-pixel image data (S140).

For example, a data compensation circuit can generate image data in which the brightness of the image data is compensated by adding a value obtained by multiplying an offset value and a gain to the input image data.

The data compensation circuit can output compensated image data to the data driver (S150). The data driver can supply the compensated image data to pixels within the compensation area.

Although the embodiments of the present invention have been described in more detail with reference to the attached drawings, the present invention is not necessarily limited to these embodiments, and various modifications may be implemented without departing from the technical spirit of the present invention. Therefore, the embodiments disclosed in this specification are not intended to limit the technical spirit of the present invention, but to explain it, and the scope of the technical spirit of the present invention is not limited by these embodiments. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. The protection scope of the present invention should be interpreted by the claims, and all technical ideas within a scope equivalent thereto should be interpreted as being included in the scope of the rights of the present invention.

Claims (12)

An area determination unit that determines whether a pixel to be entered with image data input in pixel units is located in a predetermined compensation area within the display area; A compensation value generation unit that generates a compensation value using a lookup table stored in advance based on the grayscale value of the image data when the pixel to which the image data is to be written is located in the compensation area; and A data compensation circuit including a data compensation unit that compensates the image data using the above compensation value. In the first paragraph, The above area determination unit is, A data compensation circuit that determines whether a pixel to which the input image data is to be written is located in a predetermined compensation area within the display area using a binary map in which the emission of light-emitting elements for each pixel is binarized and displayed. In the second paragraph, The above compensation area is, A data compensation circuit in which the number of pixel lines is less than the area in which all light-emitting elements normally emit light. In the first paragraph, The above compensation value includes an offset value and a gain, The above lookup table is, A data compensation circuit comprising a first lookup table to which a predetermined first reference tone value and an offset value are mapped, and a second lookup table to which a predetermined second reference tone value and a gain are mapped. In paragraph 4, The above compensation value generation unit, Interpolating the offset value mapped to the first reference grayscale value of the first lookup table to estimate the offset value for the grayscale value of the image data, A data compensation circuit that estimates a gain for a grayscale value of the image data by interpolating a gain mapped to a second reference grayscale value of the second lookup table. In paragraph 5, The above compensation value generation unit, A data compensation circuit that estimates an offset value for the grayscale value of the image data by interpolating using a predetermined slope when the grayscale value of the image data is smaller than the smallest value or larger than the largest value among the first reference grayscale values. In paragraph 5, The above data compensation section, A data compensation circuit that compensates for the image data by adding a value obtained by multiplying the offset value estimated from the compensation value generation unit by the gain to the input image data. A display panel in which pixels are arranged in an area where a plurality of gate lines and a plurality of data lines intersect; A gate driver that outputs a gate signal through the above gate line; A data driver that outputs a data voltage through the above data line; and It includes a timing controller that controls the gate driver and the data driver, The above timing controller includes a data compensation circuit that compensates for image data of an input image input from an external source, The above data compensation circuit is, An area determination unit that determines whether a pixel to be entered with image data input in pixel units is located in a predetermined compensation area within the display area; A compensation value generation unit that generates a compensation value using a lookup table stored in advance based on the grayscale value of the image data when the pixel to which the image data is to be written is located in the compensation area; and A display device including a data compensation unit that compensates the image data using the compensation value. In the first paragraph, The above area determination unit is, A display device that determines whether a pixel to which the input image data is to be written is located in a predetermined compensation area within the display area using a binary map in which the emission of light-emitting elements for each pixel is binarized and displayed. In paragraph 8, The above compensation value includes an offset value and a gain, The above lookup table is, A display device comprising a first lookup table to which a predetermined first reference tone value and an offset value are mapped, and a second lookup table to which a predetermined second reference tone value and a gain are mapped. In Article 10, The above compensation value generation unit, Interpolating the offset value mapped to the first reference grayscale value of the first lookup table to estimate the offset value for the grayscale value of the image data, A display device that estimates a gain for a grayscale value of the image data by interpolating a gain mapped to a second reference grayscale value of the second lookup table. In Article 11, The above compensation value generation unit, A display device that estimates an offset value for the grayscale value of the image data by interpolating using a predetermined slope when the grayscale value of the image data is smaller than the smallest value or larger than the largest value among the first reference grayscale values.