Method for dynamically adjusting gray scale of liquid crystal display according with human eye brightness perception

Abstract

The invention discloses a liquid crystal display gray scale dynamic adjustment method conforming to human eye brightness perception. The method comprises the following steps that S1, an electro-optical characteristic curve of a liquid crystal display is obtained; s2, determining an optimal gray scale voltage range of the liquid crystal display; s3, acquiring ambient light brightness in real time; s4, determining brightness distribution of the liquid crystal display; s5, determining a human eye brightness sensitivity index range; s6, dynamically adjusting the gray scale index range of the liquid crystal display; and S7, performing gray scale driving on the liquid crystal display. By determining the optimal gray scale voltage range and dynamically adjusting the gray scale index, the gray scale offset phenomenon under different visual angles can be effectively reduced, and the human eye brightness sensitivity index can be matched with the gray scale index of the liquid crystal display under the condition of different ambient light brightness and liquid crystal display brightness, so that the human eye brightness sensitivity index can be matched with the gray scale index of the liquid crystal display. And a display effect conforming to human eye brightness perception is realized.

Description

1. Technical Field

[0001] The present invention relates to the field of display technology, and in particular to a method for dynamically adjusting grayscale of a liquid crystal display that conforms to the brightness perception of the human eye. 2. Background Technology

[0002] Liquid crystal displays (LCDs) are a type of display device that holds a significant market share in the display technology sector and are widely used in various scenarios, including commercial displays, office entertainment, healthcare, and education. In recent years, with the introduction of various high-brightness backlighting technologies, LCDs have rapidly gained popularity in outdoor applications such as in-vehicle displays, billboards, and interactive terminals. Generally, the human eye has a characteristic of brightness perception. When there are significant changes in ambient light and LCD brightness, the human eye's brightness sensitivity index also changes. Therefore, it is necessary to consider the relative brightness of the ambient light and the LCD to improve the viewing experience of LCDs in various ambient light levels.

[0003] In existing technologies, LCDs are typically driven using a fixed grayscale index. This grayscale index cannot be dynamically adjusted based on viewing angle, ambient light, and LCD brightness, and therefore cannot match the real-time changes in the human eye's brightness sensitivity index. This existing technology presents the following problems: First, the grayscale voltage curves at different viewing angles are fixed mappings and cannot be dynamically adjusted, making it difficult to eliminate grayscale shifts at different viewing angles. Second, under varying ambient light and LCD brightness conditions, the human eye's brightness sensitivity index and the LCD's grayscale index do not match, making it difficult to achieve a display effect that matches the human eye's brightness perception. 3. Summary of the Invention

[0004] To solve the above problems, the present invention proposes a method for dynamically adjusting the grayscale of a liquid crystal display that is consistent with the brightness perception of the human eye, so that the liquid crystal display has a lower grayscale offset under different viewing angles; under different ambient light brightness and liquid crystal display brightness conditions, it has a matching human eye brightness sensitivity index and liquid crystal display grayscale index, achieving a display effect that is consistent with the brightness perception of the human eye.

[0005] The method comprises the following steps:

[0006] S1. Obtain the electro-optical characteristic curve of the liquid crystal display:

[0007] Within the viewing angle range, the transmittance distribution of the liquid crystal display under different driving voltages is tested to obtain the electro-optical characteristic curve of the liquid crystal display within the viewing angle range;

[0008] S2. Determine the optimal grayscale voltage range for the LCD display:

[0009] According to the electro-optical characteristic curve of the liquid crystal display, the minimum value of the peak transmittance voltage V at each viewing angle is determined.min , determine the optimal grayscale voltage range of the LCD display [V0,V min ], where V0 is the initial voltage;

[0010] S3. Get ambient light brightness in real time:

[0011] Acquire the ambient light brightness L0 in real time within the viewing field of the LCD;

[0012] S4. Determine the brightness distribution of the LCD:

[0013] At the viewing position of the LCD, determine the brightness distribution of the LCD [L min ,L max ], where L min is the minimum brightness, L max is the highest brightness;

[0014] S5. Determine the range of the human eye brightness sensitivity index:

[0015] According to the ambient light brightness, the brightness distribution of the LCD and the brightness sensitivity characteristics of the human eye under bright field, the brightness sensitivity index range of the human eye [γ low ,γ up ], where γ low is the lower bound exponent, γ up is the upper limit index;

[0016] S6. Dynamically adjust the grayscale index range of the LCD display:

[0017] According to the brightness sensitivity index range of human eyes and its relationship with the grayscale index of LCD, the grayscale index range of LCD is dynamically adjusted [γ min ,γ max ], where γ min is the minimum grayscale index, γ min =1 / γ up ; γ max is the maximum grayscale index, γ max =1 / γ low ;

[0018] S7. Implement grayscale driving for the LCD:

[0019] Within the optimal grayscale voltage range of the liquid crystal display, the grayscale voltage is determined according to the grayscale bit number and grayscale index of the liquid crystal display, and the grayscale voltage is applied to perform grayscale driving on the liquid crystal display.

[0020] Furthermore, in step S1, the viewing angle range includes a polar angle range and an azimuth angle range, wherein the polar angle range is [0°, θ max ],θ maxIt is the maximum polar angle between the line of sight of the human eye and the normal line of the LCD display; the azimuth angle range is The maximum azimuth angle between the projection of the human eye's line of sight on the LCD plane and the horizontal direction of the LCD plane.

[0021] Preferably, the maximum polar angle θ of the viewing angle range is max <90°, maximum azimuth

[0022] Furthermore, in step S5, the brightness sensitivity characteristic of the human eye under bright field is a mapping relationship between the brightness range and the brightness sensitivity index of the human eye, and the brightness sensitivity index of the human eye is determined by the following steps:

[0023] The first step is to obtain the total brightness range of the ambient light brightness and the LCD brightness [L0+L min ,L0+L max ];

[0024] The second step is to divide the total brightness range into different sub-brightness ranges [L m ,L n ], where L0+L min ≤L m 、L0+L max ≤L n , L m <L n ;

[0025] The third step is to test viewers’ comfort with grayscale cards with different grayscale indices under different sub-brightness ranges, where the grayscale index range of the grayscale card is (0,1);

[0026] The fourth step is to identify the grayscale card that meets the brightness perception of the human eye in different sub-brightness ranges, and determine the upper and lower limits of the corresponding grayscale index as the brightness sensitivity index range of the human eye in this brightness range [γ low ,γ up ].

[0027] Furthermore, in step S7, the selected grayscale index is within the grayscale index range of the liquid crystal display.

[0028] Preferably, the selected grayscale index is an average value of the grayscale index range of the liquid crystal display.

[0029] Furthermore, the grayscale bit number of the liquid crystal display is ≥8 bits.

[0030] Preferably, the number of grayscale bits of the liquid crystal display is 8, 10, 12, 14, or 16.

[0031] The present invention has the following beneficial effects: first, the grayscale voltage and grayscale transmittance under different viewing angles become a variable mapping relationship, which can be dynamically adjusted according to the viewing angle range, and can effectively reduce the grayscale offset phenomenon under different viewing angles; second, under the conditions of different ambient light brightness and liquid crystal display brightness, it has a matching human eye brightness sensitivity index and liquid crystal display grayscale index, and can achieve a display effect that conforms to the human eye's brightness perception. IV. Description of the Figures

[0032] In order to further illustrate the technical methods in the embodiments of the present application, the required drawings are described.

[0033] Figure 1 The figure is a flow chart of a method for dynamically adjusting grayscale of a liquid crystal display in accordance with the brightness perception of the human eye according to the present invention.

[0034] Figure 2 1 is the electro-optical characteristic curve of the liquid crystal display at various viewing angles in the embodiment of the present invention.

[0035] Figure 3 1 is a grayscale voltage curve when γ=2.39 at an initial moment and γ=2.16 at a next moment in the embodiment of the present invention.

[0036] Figure 4 : is a grayscale transmittance curve of a liquid crystal display with a grayscale index γ=2.39 in an embodiment of the present invention.

[0037] Figure 5 : is a grayscale transmittance curve of a liquid crystal display with a grayscale index γ=2.16 in an embodiment of the present invention. V. Specific Implementation Methods

[0038] The present invention is described below with reference to the accompanying drawings and specific embodiments.

[0039] Figure 1 The figure is a flow chart of a method for dynamically adjusting the grayscale of a liquid crystal display in accordance with human eye brightness perception according to the present invention. The method comprises the following steps:

[0040] S1. Obtain the electro-optical characteristic curve of the liquid crystal display:

[0041] Within the viewing angle range, the transmittance distribution of the liquid crystal display under different driving voltages is tested to obtain the electro-optical characteristic curve of the liquid crystal display within the viewing angle range;

[0042] S2. Determine the optimal grayscale voltage range for the LCD display:

[0043] According to the electro-optical characteristic curve of the liquid crystal display, the minimum value of the peak transmittance voltage V at each viewing angle is determined. min, determine the optimal grayscale voltage range of the LCD display [V0,V min ], where V0 is the initial voltage;

[0044] S3. Get ambient light brightness in real time:

[0045] Acquire the ambient light brightness L0 in real time within the viewing field of the LCD;

[0046] S4. Determine the brightness distribution of the LCD:

[0047] At the viewing position of the LCD, determine the brightness distribution of the LCD [L min ,L max ], where L min is the minimum brightness, L max is the highest brightness;

[0048] S5. Determine the range of the human eye brightness sensitivity index:

[0049] According to the ambient light brightness, the brightness distribution of the LCD and the brightness sensitivity characteristics of the human eye under bright field, the brightness sensitivity index range of the human eye [γ low ,γ up ], where γ low is the lower bound exponent, γ up is the upper limit index;

[0050] S6. Dynamically adjust the grayscale index range of the LCD display:

[0051] According to the brightness sensitivity index range of human eyes and its relationship with the grayscale index of LCD, the grayscale index range of LCD is dynamically adjusted [γ min ,γ max ], where γ min is the minimum grayscale index, γ min =1 / γ up ; γ max is the maximum grayscale index, γ max =1 / γ low ;

[0052] S7. Implement grayscale driving for the LCD:

[0053] Within the optimal grayscale voltage range of the liquid crystal display, the grayscale voltage is determined according to the grayscale bit number and grayscale index of the liquid crystal display, and the grayscale voltage is applied to perform grayscale driving on the liquid crystal display.

[0054] In this embodiment, within the viewing angle range of the liquid crystal display, the maximum polar angle θ between the human eye's viewing line and the normal line of the liquid crystal display is max=70°, the polar angle range is [0°, 70°]; the maximum azimuth angle of the human eye's line of sight between the projection of the LCD plane and the horizontal direction of the LCD plane The azimuth range is [0°,360°].

[0055] The initial voltage of the LCD is V0 = 0V, and the minimum value of the peak transmittance voltage at each viewing angle is V min =4.2V, such as Figure 2 As shown, the optimal grayscale voltage range of the LCD is determined to be [0V, 4.2V].

[0056] In the viewing field of the liquid crystal display, it is determined that the ambient light brightness L0 at the initial moment is 45 nit.

[0057] At the viewing position of the LCD, the minimum brightness of the LCD at the initial moment is L min =45nit, maximum brightness L max =165nit, the brightness distribution of the LCD display is [45nit,165nit].

[0058] The steps to determine the brightness sensitivity index of the human eye at the initial moment are as follows:

[0059] The first step is to obtain the total brightness range of the sum of the ambient light brightness and the LCD brightness [90nit, 210nit];

[0060] The second step is to divide the total brightness range into different sub-brightness ranges at intervals of 40 nits: [90 nit, 130 nit], [130 nit, 170 nit], and [170 nit, 210 nit];

[0061] The third step is to test viewers’ comfort with grayscale cards with different grayscale indices under different sub-brightness ranges, where the grayscale index range of the grayscale card is (0,1);

[0062] The fourth step is to identify the grayscale card that meets the brightness perception of the human eye in different sub-brightness ranges, and determine that the brightness sensitivity index range of the human eye at the initial moment is [0.405, 0.435].

[0063] According to the range of the brightness sensitivity index of the human eye and its relationship with the grayscale index of the LCD, the grayscale index range of the LCD at the initial moment is [2.30, 2.47].

[0064] In order to achieve a good display effect, the grayscale index selected is the average value of the grayscale index range of the liquid crystal display, that is, γ=2.39.

[0065] In this embodiment, the grayscale bit number of the liquid crystal display is 10 bits, with a total of 210 =1024 grayscale values.

[0066] In the optimal grayscale voltage range of the LCD [0V, 4.2V], the grayscale voltage is determined according to the grayscale number of 10 bits and the grayscale index γ = 2.39, such as Figure 3 Then, a grayscale voltage is applied to perform grayscale driving on the liquid crystal display.

[0067] Figure 4 2 is a grayscale transmittance curve of a liquid crystal display with a grayscale index γ=2.39. It can be seen that there is no grayscale inversion in the liquid crystal display at this time, and the grayscale shift phenomenon under different viewing angles is effectively suppressed.

[0068] This embodiment provides an explanation of the dynamic grayscale adjustment at the next moment, as follows:

[0069] In the viewing field of the liquid crystal display, it is determined that the ambient light brightness L0 = 270 nit is obtained at the next moment.

[0070] At the viewing position of the LCD, the minimum brightness of the LCD at the next moment is L min =80nit, maximum brightness L max =320nit, the brightness distribution of the LCD display is [80nit,320nit].

[0071] According to the steps of the brightness sensitivity index of the human eye at the initial moment, it is determined that the range of the brightness sensitivity index of the human eye at the next moment is [0.455, 0.470].

[0072] According to the range of the brightness sensitivity index of the human eye and its relationship with the grayscale index of the LCD display, the grayscale index range of the LCD display at the next moment is [2.13, 2.19].

[0073] In order to achieve a good display effect, the grayscale index selected is the average value of the grayscale index range of the liquid crystal display, that is, γ=2.16.

[0074] In the optimal grayscale voltage range of the LCD [0V, 4.2V], the grayscale voltage is determined based on the grayscale number of 10 bits and the grayscale index γ = 2.16. Figure 3 Then, a grayscale voltage is applied to perform grayscale driving on the liquid crystal display.

[0075] Figure 5 This is the grayscale transmittance curve of the LCD with a grayscale index of γ = 2.16. It can be seen that there is no grayscale inversion in this LCD. The grayscale offset phenomenon under different viewing angles is effectively suppressed. At the same time, the human eye brightness sensitivity index and the LCD grayscale index are matched, achieving a display effect that conforms to the human eye's brightness perception.

[0076] It should be noted that the above embodiments are only specific implementations of the present invention and are only used to further describe the present invention. They should not be understood as limiting the scope of protection of the present invention. Equivalent substitutions and non-substantial modifications proposed by relevant technicians in the field based on the present invention are all within the scope of protection of the present invention.

Claims

1. A method for dynamically adjusting grayscale of a liquid crystal display in accordance with the brightness perception of the human eye, characterized in that: The method comprises the following steps: S1. Obtain the electro-optical characteristic curve of the liquid crystal display: Within the viewing angle range, the transmittance distribution of the liquid crystal display under different driving voltages is tested to obtain the electro-optical characteristic curve of the liquid crystal display within the viewing angle range; S2. Determine the optimal grayscale voltage range of the LCD display: According to the electro-optical characteristic curve of the liquid crystal display, the minimum value V of the peak transmittance voltage at each viewing angle is determined. min , determine the optimal grayscale voltage range [V0,V min ], where V0 is the initial voltage; S3. Get the ambient light brightness in real time: Acquire the ambient light brightness L0 in real time within the viewing field of the LCD display; S4. Determine the brightness distribution of the LCD display: At the viewing position of the LCD, determine the brightness distribution of the LCD [L min ,L max ], where L min is the minimum brightness, L max is the highest brightness; S5. Determine the range of human eye brightness sensitivity index: According to the ambient light brightness, the brightness distribution of the LCD display, and the brightness sensitivity characteristics of the human eye under bright field, the range of the human eye brightness sensitivity index [γ low ,γ up ], where γ low is the lower exponent, γ up is the upper limit index; S6. Dynamically adjust the grayscale index range of the LCD display: According to the range of human eye brightness sensitivity index and its relationship with the grayscale index of the LCD, the grayscale index range of the LCD is dynamically adjusted [γ min ,γ max ], where γ min is the minimum grayscale index, γ min =1 / γ up ; γ max is the maximum grayscale index, γ max =1 / γ low ; S7. Implement grayscale driving on the LCD display: In the optimal grayscale voltage range of the liquid crystal display, the grayscale voltage is determined according to the grayscale bit number and grayscale index of the liquid crystal display, and the grayscale voltage is applied to drive the liquid crystal display in grayscale.

2. The method for dynamically adjusting grayscale of a liquid crystal display in accordance with human eye brightness perception according to claim 1, characterized in that: The viewing angle range includes a polar angle range and an azimuth angle range, wherein the polar angle range is [0°, θ max ],θ max It is the maximum polar angle between the line of sight of the human eye and the normal of the LCD display; the azimuth angle range is [0°,φ max ],φ max It is the maximum azimuth angle between the projection of the human eye's line of sight on the LCD plane and the horizontal direction of the LCD plane.

3. The method for dynamically adjusting grayscale of a liquid crystal display in accordance with human eye brightness perception according to claim 1, characterized in that: The brightness sensitivity characteristic of the human eye under the bright field is a mapping relationship between the brightness range and the brightness sensitivity index of the human eye. The brightness sensitivity index of the human eye is determined by the following steps: the first step is to obtain the total brightness range [L0+L min ,L0+L max ]; The second step is to divide the total brightness range into different sub-brightness ranges [L m ,L n ], where L0+L min ≤L m 、L0+L max ≤L n , L m <L n ; The third step is to test the comfort level of viewers with grayscale cards with different grayscale indices under different sub-brightness ranges, where the grayscale index range of the grayscale card is (0,1]; The fourth step is to identify the grayscale card that meets the brightness perception of the human eye under different sub-brightness ranges, and determine the upper and lower limits of the corresponding grayscale index as the brightness sensitivity index range of the human eye under this brightness range [γ low ,γ up ].

4. The method for dynamically adjusting grayscale of a liquid crystal display in accordance with human eye brightness perception according to claim 1, characterized in that: The grayscale bit number of the liquid crystal display is ≥8 bits.

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