Patent Application
20250157380
The invention relates to an electronic circuit and a method for compensating data, more specifically, to a driver circuit and a method for compensating pixel values of display pixels.
OLED (Organic Light-Emitting Diode) panels are suitable for the development of under-display cameras because it is self-luminous. Camera under display (CUD) products are gradually being added to the OLED panels. However, there are still some issues to be addressed, mainly the challenge of improving the transmittance of the CUD region. One solution to address this issue could be to decrease the size or the number of light emitting pixels, thereby allowing the driving circuit to handle more light emitting pixels. However, this approach has the drawback of increasing the visibility of the normal region border and decreasing the resolution, which may become more noticeable. In addition, the greater change in brightness results in demura being more difficult.
The invention is directed to a driver circuit and a method for compensating pixel values of display pixels, capable of improve uneven brightness of an image sensing region, e.g. the CUD region, of a display panel.
An embodiment of the invention provides a driver circuit including a controller circuit. The controller circuit is configured to perform an image compensating operation on a display pixel of an image sensing region of a display panel to compensate a pixel value of the display pixel using a first compensating value. The image sensing region is a circular area comprising image sensors. The controller circuit determines the first compensating value according to a location of the display pixel in the image sensing region.
In an embodiment of the invention, the controller circuit determines a weight value according to the location of the display pixel in the image sensing region. The first compensating value is obtained by modifying a second compensating value according to the weight value.
In an embodiment of the invention, the controller circuit is further configured to perform the image compensating operation on a display pixel of a non-image sensing region of the display panel to compensate the pixel value of the display pixel using the second compensating value.
In an embodiment of the invention, a plurality of lookup tables are set up for the image sensing region, and the lookup tables record relationships between the weight values and the locations of the display pixels.
In an embodiment of the invention, the controller circuit determines the weight value according to the lookup tables.
In an embodiment of the invention, for a specified pixel value, the different lookup tables are set up for different regions of the image sensing region.
In an embodiment of the invention, for a specified region of the image sensing region, the different lookup tables are set up for different pixel values of the display pixels.
In an embodiment of the invention, different regions of the image sensing region have different block sizes, and the block size indicates how many display pixels share the same weight value.
In an embodiment of the invention, the lookup tables are set up for a specified pixel value by capturing a gray level variation and a brightness variation of the image sensing region.
In an embodiment of the invention, the driver circuit further includes a storage circuit. The storage circuit is coupled to the controller circuit, and configured to store the lookup tables.
In an embodiment of the invention, the image sensing region comprises a first region, a second region and a third region. The first region is a circular area. The second region is a ring area surrounding the first region, and the third region is a ring area surrounding the second region.
In an embodiment of the invention, the first region includes the image sensors and the display pixels. The second region includes driving circuits and the display pixels, and the third region includes the display pixels.
An embodiment of the invention provides a method for compensating pixel values of display pixels. The method includes: receiving pixel data, and determining a location of a display pixel that the pixel data is to be written; when the location of the display pixel is determined in an image sensing region of a display panel, determining a first compensating value according to the location of the display pixel in the image sensing region, wherein the image sensing region is a circular area comprising image sensors; and performing an image compensating operation on the display pixel of the image sensing region to compensate the pixel value of the display pixel using the first compensating value.
In an embodiment of the invention, a step of determining the first compensating value according to the location of the display pixel in the image sensing region includes: determining a weight value according to the location of the display pixel in the image sensing region; and modifying a second compensating value according to the weight value to obtain the first compensating value.
In an embodiment of the invention, the method for compensating the pixel values of the display pixels further includes: when the location of the display pixel is determined in a non-image sensing region of the display panel, performing the image compensating operation on the display pixel of the non-image sensing region to compensate the pixel value of the display pixel using the second compensating value.
In an embodiment of the invention, the method for compensating the pixel values of the display pixels further includes: setting up a plurality of lookup tables for the image sensing region by capturing a gray level variation and a brightness variation of the image sensing region, wherein the lookup tables record relationships between the weight values and the locations of the display pixels.
In an embodiment of the invention, the step of determining the first compensating value according to the location of the display pixel in the image sensing region further includes: determining the weight value according to the lookup tables.
In an embodiment of the invention, a step of setting up the plurality of lookup tables for the image sensing region includes: for a specified pixel value, setting up the different lookup tables for different regions of the image sensing region.
In an embodiment of the invention, a step of setting up the plurality of lookup tables for the image sensing region includes: for a specified region of the image sensing region, setting up the different lookup tables for different pixel values of the display pixels.
In an embodiment of the invention, different regions of the image sensing region have different block sizes, and the block size indicates how many display pixels share the same weight value.
To make the aforementioned more comprehensible, several embodiments accompanied with drawings are described in detail as follows.
The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure.
Embodiments are provided below to describe the disclosure in detail, though the disclosure is not limited to the provided embodiments, and the provided embodiments can be suitably combined. The term “coupling/coupled” or “connecting/connected” used in this specification (including claims) of the application may refer to any direct or indirect connection means. For example, “a first device is coupled to a second device” should be interpreted as “the first device is directly connected to the second device” or “the first device is indirectly connected to the second device through other devices or connection means.” In addition, the term “signal” can refer to a current, a voltage, a charge, a temperature, data, electromagnetic wave or any one or multiple signals.
The driver circuit 110 includes a controller circuit 112. The controller circuit 112 is adapted to perform an image compensating operation, e.g. a demura operation, on the display panel 120, such that the display panel 120 can display good image quality. For example, the controller circuit 112 receives pixel data PD, and compensates the data PD using a first compensating value CV1 or a second compensating value CV2 according to a location of a display pixel that the pixel data PD is to be written.
The display panel 120 includes an image sensing region 122 and a non-image sensing region 124. The image sensing region 122 is a circular area including image sensors for sensing images. The image sensors may be cameras under display (CUD). The image sensing region 122 also includes display pixels to display images. The image sensing region 122 is a transparent region with low reflection and high light transmission. In an embodiment, the image sensing region 122 displays images normally when no photo is taken, and turns into a transparent glass when a photo is taken.
The image sensing region 122 includes a first region 221, a second region 222 and a third region 223. The first region 221 is a circular area, and includes image sensors and display pixels. The second region 222 is a ring area surrounding the first region 221. The second region 222 includes driving circuits and display pixels. The driving circuits may be circuits for driving image sensors. The third region 223 is another ring area surrounding the second region 222. The third region 223 includes display pixels. In the present embodiment, the first region 221, the second region 222 and the third region 223 are concentric circles/rings.
For clarity and conciseness, structures of the image sensors, the display pixels and the driving circuits are not depicted in
The non-image sensing region 124 is an area including display pixels, touch sensors and/or fingerprint sensors to perform a display function, a touch sensing function and/or a fingerprint sensing function, respectively. The driver circuit 110 is also adapted to drive the display panel 120 to perform the display function, the touch sensing function and/or the fingerprint sensing function.
Regarding hardware structures of the components in the embodiment of
In the present embodiment, the controller circuit 112 is configured to perform the image compensating operation on the display panel 120. The image compensating operation may be the demura operation. The demura operation is a technology that eliminates display mura and balances the brightness or the gray level of the image. For example, the controller circuit 112 receives the pixel data PD, and determines a location of a display pixel that the pixel data PD is to be written. When the location of the display pixel is determined in the non-image sensing region 124, the controller circuit 112 performs the image compensating operation on the display pixel of the non-image sensing region 124 of the display panel 120 to compensate the pixel value of the display pixel using a second compensating value CV2. The second compensating value CV2 may be obtained with reference to suitable demura methods known in the related art.
When the location of the display pixel is determined in the image sensing region 122, the controller circuit 112 performs the image compensating operation on the display pixel of the image sensing region 122 of the display panel 120 to compensate the pixel value of the display pixel using a first compensating value CV1. The first compensating value CV1 may be obtained by modifying the second compensating value CV2 according to a weight value Wd, which may be formulated as:
CV1=(1+Wd)×CV2+bn (1)
where CV1 is the first compensating value, CV2 is the second compensating value for the image sensing region 122 before modification, Wd is the weight value, and bn is a preset fine tuning parameter. The subscript n of the fine tuning parameter bn is equal to 1, 2 or 3 for the first region 221, the second region 222 and the third region 223, respectively.
In the present embodiment, the controller circuit 112 may determine the weight value Wd according to the location of the display pixel in the image sensing region 122, as illustrated in
The controller circuit 112 calculates the distance d between the display pixel and the center of circle O, and determines the weight value Wd of the display pixel according to the distance d and the lookup table 300. For example, when the distance d=d1 and 0<d1≤D1, the controller circuit 112 determines the weight value Wd as Wd1. When the distance d=d2 and D1<d2≤D2, the controller circuit 112 determines the weight value Wd as Wd2. When the distance d=d3 and D2<d2≤D3, the controller circuit 112 determines the weight value Wd as Wd3. In
Taking the electronic device 100 for example, in step S100, the controller circuit 112 receives the pixel data PD. In step S110, the controller circuit 112 determines a location of a display pixel that the pixel data PD is to be written.
When the controller circuit 112 determines that the location of the display pixel is in the non-image sensing region 124, the flow will go to step S120. In step S120, the controller circuit 112 performs the image compensating operation on the display pixel of the non-image sensing region 124 to compensate the pixel value of the display pixel using the second compensating value CV2.
When the controller circuit 112 determines that the location of the display pixel is in the image sensing region 122, the flow will go to step S130. In step S130, the controller circuit 112 determines the weight value Wd and the first compensating value CV1 according to the location of the display pixel in the image sensing region 122. For example, the weight value Wd can be determined according to the lookup table 300, and the first compensating value CV1 can be determined according to formula (1). In step S140, the controller circuit 112 performs the image compensating operation on the display pixel of the image sensing region 122 to compensate the pixel value of the display pixel using the first compensating value CV1.
The method for compensating pixel values of display pixels described in the embodiment of the invention is sufficiently taught, suggested, and embodied in the embodiments illustrated in
Taking the electronic device 100 for example, in step S200, the controller circuit 112 receives the pixel data PD, and determines a location of a display pixel that the pixel data PD is to be written. In step S210, when the location of the display pixel is determined in the image sensing region 122 of the display panel 120, the controller circuit 112 determines the first compensating value CV1 according to the location of the display pixel in the image sensing region 122. In step S220, the controller circuit 112 performs the image compensating operation on the display pixel of the image sensing region 122 to compensate the pixel value of the display pixel using the first compensating value CV1.
The method for compensating pixel values of display pixels described in the embodiment of the invention is sufficiently taught, suggested, and embodied in the embodiments illustrated in
In the disclosure, a plurality of lookup tables may set up for the image sensing region 122 in advance, and the lookup tables record relationships between the weight values Wd and the locations of the display pixels. It will be described as follows.
In
To be specific, the pixel data PD of the gray level G8 are inputted to drive the image sensing region 122 to display images. The gray level variation or the brightness variation of the image sensing region 122 is captured by an external image capturing device and converted into digital signals. The digital signals are further normalized to obtain weight values of different positions. Curve fitting is performed according to the weight values to obtain the curve 600_R, and the curve 600_R is divided into zones CZ1, CZ2 and CZ3. Block sizes BKs are set for different zones CZ1, CZ2 and CZ3. The block size BK indicates how many display pixels share the same weight value.
For example, the block size BK=1 is set for the zone CZ1. It indicates each display pixel of the first region 221 has its own weight value and recorded in the lookup table G8_1 of
Therefore, for the gray level G8, the lookup tables 600_R including G8_1, G8_2 and G8_3 can be obtained. In the lookup tables G8_1, G8_2 and G8_3, n is the nth display pixels from the inside out, dn*bk, dn*bk−D1, and dn*bk−D2 are display pixel positions, and Wd is the weight value. The lookup tables of other gray levels can be obtained in a similar manner. For example, in
In addition, for a specified region of the image sensing region 122, the different lookup tables are set up for different pixel values of the display pixels. For example, in
Therefore, the controller circuit 112 can determine the weight value Wd according to the lookup tables, as illustrated in
In summary, in the embodiments of the invention, the captured mura optical data is analyzed to obtained the weight values for the three regions of the image sensing region. When displaying images, the controller circuit looks up the weight values based on the input data and the lookup tables, while taking into account the display pixel position to look up different lookup tables. The controller circuit obtains the weight values of different positions, and calculates the first compensating value, thereby compensating the pixel values of the display pixels to perform the image compensating operation. Therefore, uneven brightness of the image sensing region can be improved, and the brightness of the display panel becomes more uniform.
It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the disclosure covers modifications and variations provided that they fall within the scope of the following claims and their equivalents.
