A partitioned backlight device based on transflective display and a dimming method thereof

Abstract

This invention discloses a partitioned backlight device based on a transflective display. The device includes a partitioned backlight panel, a transflective liquid crystal screen, a light sensor array, and a control circuit unit. The emitted light from each backlight partition in the partitioned backlight panel is transmitted through the corresponding screen partition of the transflective liquid crystal screen to form transmitted light, and each screen partition reflects ambient light in front of the screen to form reflected light. The light sensor array and each backlight partition in the partitioned backlight panel are electrically connected to the control circuit unit. The light sensor array collects the ambient light intensity in front of the screen and transmits it to the control circuit unit. In the method, the control circuit unit controls the luminous intensity of each backlight partition in the partitioned backlight panel based on the ambient light intensity in front of each screen partition and the input image data, and performs pixel compensation on the input image. This invention can adaptively adjust the luminous intensity of the backlight partitions while ensuring the display quality of the image.

Description

Technical Field

[0001] This invention relates to the field of liquid crystal display technology, specifically to a zoned backlight device and its dimming method based on a transflective display. Background Technology

[0002] Local dimming technology is now widely used in the LCD display field. The core of local dimming is to divide the traditional single-controlled backlight into multiple independent areas, each of which can independently adjust its brightness according to the content displayed, thereby improving image quality contrast and reducing energy consumption. Currently, local dimming technology is primarily used in common transmissive LCD screens. However, in some applications with complex ambient light conditions, local dimming technology based on transmissive LCD screens has limitations. For example, in automotive displays, long, narrow screens may have parts exposed to strong sunlight and parts in shadow, with significantly different backlight brightness requirements for the two display areas.

[0003] Therefore, some have proposed using an array of light sensors to collect the ambient light intensity of different screen zones, thereby adaptively adjusting the brightness of the backlight in those zones to achieve a clearer display. While this method can improve display quality under complex ambient lighting conditions, it requires significantly increasing the backlight brightness in high-brightness environments, which negatively impacts energy consumption and heat dissipation.

[0004] Transmissive liquid crystal displays (LCDs) are one of the main methods for solving the problem of visibility in strong light. In bright ambient light, they can achieve clear display primarily by relying on reflected light, while in low light conditions, they can rely on backlighting to provide brightness, overcoming the limitations of transmissive LCDs. However, currently, transmissive LCDs lack corresponding local dimming backlight modulation algorithms, failing to fully utilize their advantages in various complex lighting environments. Summary of the Invention

[0005] This invention provides a zoned backlight device and its dimming method based on transflective liquid crystal display, which solves the problem of the lack of backlight modulation algorithm in the prior art. It enables the transflective liquid crystal display to adaptively modulate the brightness of each backlight zone under complex ambient lighting conditions, so as to make full use of the energy of reflected light, thereby reducing power consumption and improving display quality.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A partitioned backlight device based on a transflective display includes a liquid crystal display screen and a backlight panel. The backlight panel is a partitioned backlight panel (1) composed of several backlight partitions. The liquid crystal display screen is a transflective liquid crystal display screen (2). The luminous intensity of each backlight partition in the partitioned backlight panel (1) is controllable. The area of ​​the transflective liquid crystal display screen (2) corresponding to each backlight partition of the partitioned backlight panel (1) forms a screen partition of the transflective liquid crystal display screen (2). The emitted light from each backlight partition in the partitioned backlight panel (1) is transmitted through the screen partition corresponding to the transflective liquid crystal display screen (2) to form transmitted light. Each screen partition of the transflective liquid crystal display screen (2) reflects the ambient light in front of the screen to form reflected light.

[0008] It also includes a light sensor array (3) and a control circuit unit (4). The light sensor array (3) collects the ambient light intensity in front of the semi-transparent and semi-reflective liquid crystal screen (2). The light sensor array (3) is electrically connected to the control circuit unit (4). The control circuit unit (4) is also electrically connected to each backlight zone in the partitioned backlight panel (1).

[0009] The ambient light intensity collected by the light sensor array (3) is transmitted to the control circuit unit (4). The control circuit unit (4) obtains the ambient light intensity of each screen partition of the transflective liquid crystal screen (2). The control circuit unit (4) also acquires the input image data of the transflective liquid crystal screen (2). Based on the ambient light intensity of each screen partition and the input image data, the control circuit unit (4) controls the luminous intensity of each backlight partition in the partition backlight panel (1) in real time. The control circuit unit (4) also performs pixel compensation on the input image.

[0010] Furthermore, the light sensor array (3) is composed of several light sensors, which are distributed in front of each screen partition of the transflective liquid crystal screen (2). The light sensor array (3) directly collects the ambient light intensity in front of each screen partition of the transflective liquid crystal screen (2) and transmits it to the control circuit unit (4). Thus, the control circuit unit (4) obtains the ambient light intensity in front of each screen partition of the transflective liquid crystal screen (2).

[0011] Furthermore, the light sensor array (3) is composed of several light sensors, each of which is distributed around the front of the transflective liquid crystal screen (2). The light sensor array (3) collects the ambient light intensity around the entire transflective liquid crystal screen (2) and transmits it to the control circuit unit (4). The control circuit unit (4) then indirectly obtains the ambient light intensity of each screen partition through calculation.

[0012] A dimming method for the aforementioned local dimming backlight device based on a transflective display includes the following steps:

[0013] Step 1: Obtain the ambient light intensity in front of each screen partition of the transflective LCD screen (2) and the input image data of the transflective LCD screen (2);

[0014] Step 2: Calculate the reflected light intensity of each screen partition based on the ambient light intensity in front of each screen partition.

[0015] Step 3: Based on the reflected light intensity of each screen partition and the maximum transmitted light intensity of the transflective liquid crystal screen (2), the luminous brightness of each backlight partition in the partition backlight panel (1) is modulated, and at the same time, pixel compensation is performed on the image data of each screen partition of the transflective liquid crystal screen (2).

[0016] Furthermore, in step 2, the formula for calculating the reflected light intensity of each screen partition of the transflective liquid crystal screen (2) is as follows:

[0017]

[0018] Where: L re (m,n) represents the reflected light intensity of the screen partition with coordinates (m,n) in the original image; I(m,n) represents the grayscale value of the screen partition with coordinates (m,n) in the original image, which is obtained by statistical analysis of the grayscale values ​​of all pixels within the corresponding screen partition; γ represents the gamma value of the LCD screen; L am (m,n) represents the ambient light intensity in front of the screen partition with coordinates (m,n); re represents the reflectivity of the transflective LCD screen.

[0019] Furthermore, step 3 proceeds as follows:

[0020] The reflected light intensity of each screen partition of the transflective liquid crystal screen (2) is compared with the highest transmitted light intensity of the transflective liquid crystal screen (2).

[0021] If the comparison result shows that the reflected light intensity of the screen partition at coordinates (m,n) is greater than or equal to the highest transmitted light intensity, then the brightness of the backlight partition corresponding to the screen partition at coordinates (m,n) is set to 0, and the pixel values ​​within the screen partition at coordinates (m,n) are compensated using the following formula:

[0022]

[0023] In the formula: I'(x,y) represents the pixel value at coordinates (x,y) within the screen partition with coordinates (m,n) after pixel compensation; I(x,y) represents the original pixel value at coordinates (x,y) within the screen partition with coordinates (m,n); L H This represents the highest transmitted light intensity of a transflective LCD screen.

[0024] When the comparison result is the reflected light intensity L of the screen partition with coordinates (m,n)re If (m,n) is less than the maximum transmitted light intensity, then an iterative method is used for pixel compensation and brightness modulation of the corresponding backlight zone.

[0025] Furthermore, the iterative process is as follows:

[0026] Step 3.1) If I(m,n) is less than 255, then let I(m,n) = I(m,n) + 1, recalculate the reflected light intensity using the following formula, and proceed to step 3.2):

[0027] L′ re (m,n)=(I(m,n) / 255) γ ×L am ×re

[0028] Otherwise, proceed to step 3.4);

[0029] Step 3.2) If L' re If (m,n) is less than the highest transmitted light intensity and I(m,n) is less than or equal to 255, then repeat step 3.1);

[0030] Otherwise, proceed to step 3.3).

[0031] Step 3.3) The pixel values ​​within the screen partition at coordinates (m,n) are compensated using the following formula:

[0032]

[0033] At the same time, the backlight brightness of the screen partition with coordinates (m,n) is set to 0.

[0034] Step 3.4) Compensate the pixel values ​​within the screen partition at coordinates (m,n) using the following formula:

[0035]

[0036] At the same time, the luminance of the backlight zone corresponding to the screen partition with coordinates (m,n) is set as shown in the following formula:

[0037] L B (m,n)=(L H -L′ re (m,n))÷tr

[0038] In the formula, tr represents the transmittance of the transflective liquid crystal display screen.

[0039] Compared with the prior art, the advantages of the present invention are:

[0040] The beneficial technical effects of this invention are reflected in:

[0041] 1. The device of the present invention collects the ambient light intensity in front of each screen partition in real time through an array of optical sensors. It can adaptively adjust the luminous intensity of the backlight partition under complex lighting conditions, making full use of the energy of ambient light to reduce backlight power consumption. Its advantages are particularly prominent in high-brightness ambient light scenarios.

[0042] 2. The dimming algorithm proposed in this invention modulates the luminous brightness of the backlight zone corresponding to each screen partition by determining the relationship between the reflected light intensity and the highest transmitted light intensity of each screen partition of the transflective liquid crystal screen. At the same time, it performs corresponding pixel compensation on the image data of each screen partition. This can maintain the uniformity of the display brightness of each screen partition of the screen while maximizing the utilization of ambient light energy, thus ensuring the display quality of the image. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the partitioned backlight device based on a semi-transparent and semi-reflective display according to an embodiment of the present invention.

[0044] Figure 2 This is a flowchart of the dimming method according to an embodiment of the present invention.

[0045] Figure 3 This is a flowchart of the backlight modulation and pixel compensation algorithm in the dimming method of this invention. Detailed Implementation

[0046] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0047] like Figure 1 As shown, this embodiment discloses a zoned backlight device based on a transflective display, including a zoned backlight panel 1, a transflective liquid crystal screen 2, a light sensor array 3, and a control circuit unit 4. Wherein:

[0048] The partitioned backlight panel 1 consists of several backlight partitions, each of which consists of several light-emitting elements, and the light intensity of each backlight partition can be controlled independently.

[0049] The transflective LCD screen 2 transmits the light emitted from the partition backlight panel 1, and the transflective LCD screen 2 reflects the ambient light in front of the screen.

[0050] A partitioned backlight panel 1 is disposed on the back of the transflective LCD screen 2, thereby forming screen partitions of the transflective LCD screen 2 corresponding to each backlight partition of the partitioned backlight panel 1. The emitted light from each backlight partition in the partitioned backlight panel 1 is transmitted through the corresponding screen partition of the transflective LCD screen 2 to form transmitted light, and each screen partition of the transflective LCD screen 2 reflects the ambient light in front of the screen to form reflected light.

[0051] The light sensor array 3 consists of several light sensors, each of which is electrically connected to the control circuit unit 4 for signal transmission. In the light sensor array 3, several light sensors are distributed in front of each screen partition of the transflective liquid crystal display 2. Each light sensor in the light sensor array 3 directly collects the ambient light intensity in front of the corresponding screen partition of the transflective liquid crystal display 2 and transmits it to the control circuit unit 4. Thus, the control circuit unit 4 directly obtains the ambient light intensity in front of each screen partition of the transflective liquid crystal display 2.

[0052] Alternatively, in the light sensor array 3, each light sensor is distributed around the front of the transflective liquid crystal screen 2. The light sensors in the light sensor array 3 collect the ambient light intensity around the entire transflective liquid crystal screen 2 and transmit it to the control circuit unit 4. The control circuit unit 4 then indirectly obtains the ambient light intensity of each screen partition through calculation.

[0053] The control circuit unit 4 is also electrically connected to each backlight zone in the partitioned backlight panel 1, and the control circuit unit 4 also acquires the input image data of the transflective LCD screen 2. Based on the ambient light intensity in front of each screen zone and the characteristics of the input image, the control circuit unit 4 controls the luminous intensity of the backlight zone in the partitioned backlight panel 1 corresponding to each screen zone in real time, and performs pixel compensation on the input image to fully utilize the ambient light intensity to reduce the backlight luminous intensity, while maintaining the uniformity of display brightness of the transflective display under various ambient lighting conditions.

[0054] like Figure 2 As shown, this embodiment also discloses a dimming method for the above-mentioned local dimming backlight device based on a transflective display, including the following steps:

[0055] Step 1: Control circuit unit 4 directly or indirectly acquires the ambient light intensity in front of each screen partition of transflective LCD 2, and control circuit unit 4 acquires the input image data of transflective LCD 2.

[0056] Step 2: Control circuit unit 4 calculates the reflected light intensity of each screen partition based on the ambient light intensity in front of each screen partition of the transflective liquid crystal screen 2. The calculation formula is as follows:

[0057]

[0058] Where: L re (m,n) represents the reflected light intensity of the screen partition with coordinates (m,n) in the original image; I(m,n) represents the grayscale value of the screen partition with coordinates (m,n) in the original image, which is obtained by statistical analysis after extracting the grayscale values ​​of all pixels in the corresponding screen partition using an existing backlight extraction algorithm; γ represents the gamma value of the LCD screen; L am(m,n) represents the ambient light intensity in front of the screen partition with coordinates (m,n); re represents the reflectivity of the transflective LCD screen.

[0059] Step 3: Based on the reflected light intensity of each screen partition and the maximum transmitted light intensity of the transflective LCD screen 2, modulate the luminous brightness of each backlight partition in the partitioned backlight panel 1, and simultaneously perform pixel compensation on the image data of each screen partition of the transflective LCD screen 2. The maximum transmitted light intensity of the transflective LCD screen 2 refers to the screen transmitted light intensity of the transflective LCD screen 2 under the condition of maximum backlight brightness and maximum image pixel grayscale value. For example... Figure 3 As shown, the specific process is as follows:

[0060] The reflected light intensity of each screen partition of the transflective liquid crystal screen 2 calculated in step 2 is compared with the highest transmitted light intensity of the transflective liquid crystal screen 2.

[0061] If the comparison result shows that the reflected light intensity of the screen partition at coordinates (m,n) is greater than or equal to the highest transmitted light intensity, then the brightness of the backlight partition corresponding to the screen partition at coordinates (m,n) is set to 0, and the pixel values ​​within the screen partition at coordinates (m,n) are compensated using the following formula:

[0062]

[0063] In the formula: I'(x,y) represents the pixel value at coordinates (x,y) within the screen partition with coordinates (m,n) after pixel compensation; I(x,y) represents the original pixel value at coordinates (x,y) within the screen partition with coordinates (m,n); L H This represents the highest transmitted light intensity of a transflective LCD screen.

[0064] When the comparison result is the reflected light intensity L of the screen partition with coordinates (m,n) re If (m,n) is less than the maximum transmitted light intensity, then an iterative method is used for pixel compensation and brightness modulation of the corresponding backlight zone. The iterative method process is as follows:

[0065] Step 3.1) If I(m,n) is less than 255, then let I(m,n) = I(m,n) + 1, recalculate the reflected light intensity using the following formula, and proceed to step 3.2):

[0066] L′ re (m,n)=(I(m,n) / 255) γ ×L am ×re

[0067] Otherwise, proceed to step 3.4);

[0068] Step 3.2) If L' reIf (m,n) is less than the highest transmitted light intensity and I(m,n) is less than or equal to 255, then repeat step 3.1);

[0069] Otherwise, proceed to step 3.3).

[0070] Step 3.3) The pixel values ​​within the screen partition at coordinates (m,n) are compensated using the following formula:

[0071]

[0072] At the same time, the backlight brightness of the screen partition with coordinates (m,n) is set to 0.

[0073] Step 3.4) Compensate the pixel values ​​within the screen partition at coordinates (m,n) using the following formula:

[0074]

[0075] At the same time, the luminance of the backlight zone corresponding to the screen partition with coordinates (m,n) is set as shown in the following formula:

[0076] L B (m,n)=(L H -L′ re (m,n))÷tr

[0077] In the formula, tr represents the transmittance of the transflective liquid crystal display screen.

[0078] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. These embodiments are merely descriptions of preferred embodiments and are not intended to limit the scope or concept of the invention. The specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. Such combinations, as long as they do not violate the spirit of the present invention, should also be considered as part of this disclosure. To avoid unnecessary repetition, the present invention will not further describe the various possible combinations.

[0079] This invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this invention and without departing from the design idea of ​​this invention, all modifications and improvements made by those skilled in the art to the technical solutions of this invention should fall within the protection scope of this invention. The technical content for which protection is sought in this invention has been fully described in the claims.

Claims

1. A dimming method for a zoned backlight device based on a transflective display, characterized in that, Includes the following steps: Step 1: Obtain the ambient light intensity in front of each screen partition of the transflective liquid crystal display (2) and the input image data of the transflective liquid crystal display (2); Step 2: Calculate the reflected light intensity of each screen partition based on the ambient light intensity in front of each screen partition. Step 3: Based on the reflected light intensity of each screen partition and the maximum transmitted light intensity of the transflective liquid crystal screen (2), the luminous brightness of each backlight partition in the partition backlight panel (1) is modulated, and at the same time, the image data of each screen partition of the transflective liquid crystal screen (2) is pixel compensated. The process of step 3 is as follows: The reflected light intensity of each screen partition of the transflective liquid crystal screen (2) is compared with the highest transmitted light intensity of the transflective liquid crystal screen (2). If the comparison result shows that the reflected light intensity of the screen partition at coordinates (m,n) is greater than or equal to the highest transmitted light intensity, then the brightness of the backlight partition corresponding to the screen partition at coordinates (m,n) is set to 0, and the pixel values ​​within the screen partition at coordinates (m,n) are compensated using the following formula: In the formula: I'(x,y) represents the pixel value at coordinates (x,y) within the screen partition with coordinates (m,n) after pixel compensation; I(x,y) represents the original pixel value at coordinates (x,y) within the screen partition with coordinates (m,n); L H This represents the highest transmitted light intensity of a transflective LCD screen. When the comparison result is the reflected light intensity L of the screen partition with coordinates (m,n) re If (m,n) is less than the maximum transmitted light intensity, then an iterative method is used for pixel compensation and brightness modulation of the corresponding backlight zone.

2. The dimming method for a zoned backlight device based on a transflective display according to claim 1, characterized in that, In step 2, the formula for calculating the reflected light intensity of each screen partition of the transflective liquid crystal screen (2) is as follows: Where: L re (m,n) represents the reflected light intensity of the screen partition with coordinates (m,n) in the original image; I(m,n) represents the grayscale value of the screen partition with coordinates (m,n) in the original image, which is obtained by statistical analysis of the grayscale values ​​of all pixels within the corresponding screen partition; γ represents the gamma value of the LCD screen; L am (m,n) represents the ambient light intensity in front of the screen partition with coordinates (m,n); re represents the reflectivity of the transflective LCD screen.

3. The dimming method for a zoned backlight device based on a transflective display according to claim 1, characterized in that, The iterative method process is as follows: Step 3.1) If I(m,n) is less than 255, then let I(m,n) = I(m,n) + 1, recalculate the reflected light intensity using the following formula, and proceed to step 3.2): Otherwise, proceed to step 3.4). Step 3.2) If L' re If (m,n) is less than the highest transmitted light intensity and I(m,n) is less than or equal to 255, then repeat step 3.1). Otherwise, proceed to step 3.3). Step 3.3) Compensate the pixel values ​​within the screen partition at coordinates (m,n) using the following formula: At the same time, the backlight brightness of the screen partition with coordinates (m,n) is set to 0; Step 3.4) Compensate the pixel values ​​within the screen partition at coordinates (m,n) using the following formula: At the same time, the luminance of the backlight zone corresponding to the screen partition with coordinates (m,n) is set as shown in the following formula: In the formula, tr represents the transmittance of the transflective liquid crystal display screen.

4. A zoned backlight device based on a transflective display, used to implement the dimming method described in claim 1, characterized in that, The system includes a liquid crystal display (LCD) screen and its backlight panel. The backlight panel is a partitioned backlight panel (1) composed of several backlight partitions. The LCD screen is a transflective liquid crystal display (2). The luminous intensity of each backlight partition in the partitioned backlight panel (1) is controllable. The transflective liquid crystal display (2) forms a screen partition of the transflective liquid crystal display (2) corresponding to each backlight partition of the partitioned backlight panel (1). The emitted light from each backlight partition in the partitioned backlight panel (1) is transmitted through the screen partition corresponding to the transflective liquid crystal display (2) to form transmitted light. Each screen partition of the transflective liquid crystal display (2) reflects the ambient light in front of the screen to form reflected light. It also includes a light sensor array (3) and a control circuit unit (4). The light sensor array (3) collects the ambient light intensity in front of the semi-transparent and semi-reflective liquid crystal screen (2). The light sensor array (3) is electrically connected to the control circuit unit (4). The control circuit unit (4) is also electrically connected to each backlight zone in the partitioned backlight panel (1). The ambient light intensity collected by the light sensor array (3) is transmitted to the control circuit unit (4). The control circuit unit (4) obtains the ambient light intensity of each screen partition of the transflective liquid crystal screen (2). The control circuit unit (4) also acquires the input image data of the transflective liquid crystal screen (2). Based on the ambient light intensity and input image data of each screen partition, the control circuit unit (4) controls the luminous intensity of each backlight partition in the partition backlight panel (1) in real time. The control circuit unit (4) also performs pixel compensation on the input image.

5. The zoned backlight device based on a transflective display according to claim 4, characterized in that, The light sensor array (3) is composed of several light sensors, which are distributed in front of each screen partition of the transflective liquid crystal screen (2). The light sensor array (3) directly collects the ambient light intensity in front of each screen partition of the transflective liquid crystal screen (2) and transmits it to the control circuit unit (4). Thus, the control circuit unit (4) obtains the ambient light intensity in front of each screen partition of the transflective liquid crystal screen (2).

6. The zoned backlight device based on a transflective display according to claim 4, characterized in that, The light sensor array (3) consists of several light sensors, each of which is distributed around the front of the transflective liquid crystal screen (2). The light sensor array (3) collects the ambient light intensity around the entire transflective liquid crystal screen (2) and transmits it to the control circuit unit (4). The control circuit unit (4) then indirectly obtains the ambient light intensity of each screen partition through calculation.

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