A method for dynamic grayscale adjustment of liquid crystal displays that conforms to human eye brightness perception

Abstract

This invention discloses a method for dynamically adjusting the grayscale of a liquid crystal display (LCD) to conform to human eye brightness perception, comprising the following steps: S1, acquiring the electro-optical characteristic curve of the LCD; S2, determining the optimal grayscale voltage range of the LCD; S3, acquiring ambient light brightness in real time; S4, determining the brightness distribution of the LCD; S5, determining the range of human eye brightness sensitivity index; S6, dynamically adjusting the grayscale index range of the LCD; and S7, implementing grayscale driving on the LCD. By determining the optimal grayscale voltage range and dynamically adjusting the grayscale index, this invention can effectively reduce grayscale shift at different viewing angles. Furthermore, under different ambient light brightness and LCD brightness conditions, it can match the human eye brightness sensitivity index with the LCD grayscale index, achieving a display effect that conforms to human eye brightness perception.

Description

I. Technical Field

[0001] This invention relates to the field of display technology, and more specifically to a method for dynamically adjusting the grayscale of a liquid crystal display in accordance with human eye brightness perception. II. Background Technology

[0002] Liquid crystal displays (LCDs) are display devices that hold a significant market share in the display technology field and are widely used in various scenarios, including commercial displays, office entertainment, medical and educational applications. In recent years, with the emergence of various high-brightness backlight technologies, LCDs have seen rapid adoption in outdoor applications such as automotive displays, advertising billboards, and interactive terminals. Generally, the human eye has brightness perception characteristics; when there are significant changes in ambient light brightness and LCD brightness, the human eye's brightness sensitivity index also changes. Therefore, it is necessary to consider both ambient light brightness and LCD brightness to improve the viewing experience of LCDs under various ambient light conditions.

[0003] In existing technologies, liquid crystal displays (LCDs) typically use a fixed grayscale index for driving, which cannot dynamically adjust the grayscale index based on viewing angle, ambient light, and LCD brightness, thus failing to match the real-time changing human eye brightness sensitivity index. Existing technologies suffer from the following problems: First, the grayscale voltage curves at different viewing angles have a fixed mapping relationship, making dynamic adjustment impossible and hindering the elimination of grayscale shifts at different viewing angles; second, under varying ambient light and LCD brightness conditions, the human eye brightness sensitivity index and the LCD grayscale index become mismatched, making it difficult to achieve a display effect that conforms to human eye brightness perception. III. Summary of the Invention

[0004] To address the aforementioned issues, this invention proposes a dynamic grayscale adjustment method for liquid crystal displays that conforms to human eye brightness perception. This method enables the liquid crystal display to exhibit low grayscale shift under different viewing angles and to match the human eye brightness sensitivity index with the liquid crystal display grayscale index under different ambient light and liquid crystal display brightness conditions, thereby achieving a display effect that conforms to human eye brightness perception.

[0005] The method includes the following steps:

[0006] S1. Obtain the electro-optic 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 was tested, and the electro-optic characteristic curves of the liquid crystal display within the viewing angle range were obtained.

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

[0009] Based on the electro-optic characteristic curve of the liquid crystal display, determine the minimum value V of the peak transmittance voltage at various viewing angles.min Determine the optimal grayscale voltage range [V0, V] for the LCD display. min ], where V0 is the initial voltage;

[0010] S3. Real-time acquisition of ambient light intensity:

[0011] Within the viewing area of ​​the LCD monitor, the ambient light intensity L0 is acquired in real time.

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

[0013] Determine the brightness distribution of the LCD monitor at the viewing position [L]. min ,L max ], where L min It is the lowest brightness, L max That is the highest brightness;

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

[0015] Based on ambient light intensity, the brightness distribution of the liquid crystal display, and the human eye's brightness sensitivity characteristics under bright field conditions, the range of the human eye brightness sensitivity index [γ] is determined. low ,γ up ], where γ low It is the lower limit exponent, γ up It is the upper limit index;

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

[0017] Based on the range of human eye luminance sensitivity index and its relationship with the grayscale index of the liquid crystal display, the grayscale index range of the liquid crystal display is dynamically adjusted [γ]. min ,γ max ], where γ min It is the minimum gray level index, γ min =1 / γ up ;γ max It is the maximum grayscale index, γ max =1 / γ low ;

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

[0019] Within the optimal grayscale voltage range of the LCD, the grayscale voltage is determined according to the number of grayscale bits and the grayscale index of the LCD, and the grayscale voltage is applied to drive the LCD to grayscale.

[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 maxThe maximum polar angle between the human eye's line of sight and the normal to the liquid crystal display; the azimuth range is... The maximum azimuth angle between the projection of the human eye's line of sight onto the plane of the LCD and the horizontal direction of the LCD plane.

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

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

[0023] The first step is to obtain the total brightness range [L0+L], which is the sum of the ambient light brightness and the LCD screen brightness. 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 the viewer's comfort level with grayscale cards of 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 grayscale cards that conform to human eye brightness perception within different sub-brightness ranges, and determine the upper and lower limits of their corresponding grayscale indices as the human eye brightness sensitivity index range [γ] within that brightness range. 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 the average value of the grayscale index range of the liquid crystal display.

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

[0030] Preferably, the number of gray levels 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 shift phenomenon under different viewing angles; Second, 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, which can achieve a display effect that conforms to human eye brightness perception. IV. Description of the attached drawings

[0032] To further illustrate the technical methods in the embodiments of this application, the accompanying drawings used are described.

[0033] Figure 1 This is a flowchart illustrating a method for dynamically adjusting the grayscale of a liquid crystal display that conforms to human eye brightness perception, as described in this invention.

[0034] Figure 2 These are the electro-optic characteristic curves of the liquid crystal display under various viewing angles in the embodiments of the present invention.

[0035] Figure 3 The figures show the grayscale voltage curves at the initial time γ = 2.39 and the next time γ = 2.16 in this embodiment of the invention.

[0036] Figure 4 This is the 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 This is the grayscale transmittance curve of a liquid crystal display with a grayscale index γ = 2.16 in an embodiment of the present invention. V. Detailed Implementation Methods

[0038] The present invention will now be described in conjunction with the accompanying drawings and specific embodiments.

[0039] Figure 1 This is a flowchart illustrating a method for dynamically adjusting the grayscale of a liquid crystal display to conform to human eye brightness perception, as described in this invention. The method includes the following steps:

[0040] S1. Obtain the electro-optic 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 was tested, and the electro-optic characteristic curves of the liquid crystal display within the viewing angle range were obtained.

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

[0043] Based on the electro-optic characteristic curve of the liquid crystal display, determine the minimum value V of the peak transmittance voltage at various viewing angles. minDetermine the optimal grayscale voltage range [V0, V] for the LCD display. min ], where V0 is the initial voltage;

[0044] S3. Real-time acquisition of ambient light intensity:

[0045] Within the viewing area of ​​the LCD monitor, the ambient light intensity L0 is acquired in real time.

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

[0047] Determine the brightness distribution of the LCD monitor at the viewing position [L]. min ,L max ], where L min It is the lowest brightness, L max That is the highest brightness;

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

[0049] Based on ambient light intensity, the brightness distribution of the liquid crystal display, and the human eye's brightness sensitivity characteristics under bright field conditions, the range of the human eye brightness sensitivity index [γ] is determined. low ,γ up ], where γ low It is the lower limit exponent, γ up It is the upper limit index;

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

[0051] Based on the range of human eye luminance sensitivity index and its relationship with the grayscale index of the liquid crystal display, the grayscale index range of the liquid crystal display is dynamically adjusted [γ]. min ,γ max ], where γ min It is the minimum gray level index, γ min =1 / γ up ;γ max It is the maximum grayscale index, γ max =1 / γ low ;

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

[0053] Within the optimal grayscale voltage range of the LCD, the grayscale voltage is determined according to the number of grayscale bits and the grayscale index of the LCD, and the grayscale voltage is applied to drive the LCD to grayscale.

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

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

[0056] Within the viewing field of view of the LCD monitor, the ambient light luminance L0 is determined to be 45 nits at the initial moment.

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

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

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

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

[0061] The third step is to test the viewer's comfort level with grayscale cards of 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 grayscale cards that match human eye brightness perception under different sub-brightness ranges, and determine that the human eye brightness sensitivity index range at the initial moment is [0.405, 0.435].

[0063] Based on the range of human eye brightness sensitivity index and its relationship with the grayscale index of liquid crystal display, the grayscale index range of liquid crystal display at the initial moment is [2.30, 2.47].

[0064] To achieve good display results, the grayscale index selected is the average value of the grayscale index range of the LCD monitor, i.e., γ = 2.39.

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

[0066] Within the optimal grayscale voltage range of the LCD monitor [0V, 4.2V], the grayscale voltage is determined based on a grayscale bit depth of 10 bits and a grayscale index γ = 2.39, as follows: Figure 3 As shown. Then, a grayscale voltage is applied to drive the liquid crystal display at this time.

[0067] Figure 4 The grayscale transmittance curve of the liquid crystal display with grayscale index γ = 2.39 shows 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 adjustment of grayscale at the next time step, as follows:

[0069] Within the viewing field of view of the LCD monitor, determine the ambient light luminance L0 = 270 nits for the next moment.

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

[0071] Following the steps described above for determining the human eye luminance sensitivity index at the initial moment, the range of the human eye luminance sensitivity index at the next moment is determined to be [0.455, 0.470].

[0072] Based on the range of human eye brightness sensitivity index and its relationship with the grayscale index of liquid crystal display, the grayscale index range of the liquid crystal display at the next moment is [2.13, 2.19].

[0073] To achieve good display results, the grayscale index selected is the average value of the grayscale index range of the LCD monitor, i.e., γ = 2.16.

[0074] Within the optimal grayscale voltage range of the LCD monitor [0V, 4.2V], the grayscale voltage is determined based on a grayscale bit depth of 10 bits and a grayscale index γ = 2.16 as follows: Figure 3 As shown. Then, a grayscale voltage is applied to drive the liquid crystal display at this time.

[0075] Figure 5 The grayscale transmittance curve of the liquid crystal display with grayscale index γ = 2.16 shows that there is no grayscale inversion in the liquid crystal display at this time. The grayscale shift phenomenon under different viewing angles is effectively suppressed. At the same time, it has a matching human eye brightness sensitivity index and liquid crystal display grayscale index, and achieves a display effect that conforms to human eye brightness perception.

[0076] It should be noted that the above embodiments are merely specific implementations of the present invention and are only used for further description of the present invention, and should not be construed as limiting the scope of protection of the present invention. Equivalent substitutions and non-substantial modifications proposed by those skilled in the art based on the present invention are all within the scope of protection of the present invention.

Claims

1. A method for dynamically adjusting the grayscale of a liquid crystal display that conforms to human eye brightness perception, characterized in that, The method includes the following steps: S1. Obtain the electro-optic characteristic curve of the liquid crystal display: Within the viewing angle range, the transmittance distribution of the liquid crystal display under different driving voltages was tested, and the electro-optic characteristic curves of the liquid crystal display within the viewing angle range were obtained. S2. Determine the optimal grayscale voltage range for the LCD monitor: Based on the electro-optic characteristic curve of the liquid crystal display, determine the minimum value V of the peak transmittance voltage at various viewing angles. min Determine the optimal grayscale voltage range [V0, V] for the LCD display. min ], where V0 is the initial voltage; S3. Real-time acquisition of ambient light intensity: Within the viewing area of ​​the LCD monitor, the ambient light intensity L0 is acquired in real time. S4. Determine the brightness distribution of the LCD display: Determine the brightness distribution of the LCD monitor at the viewing position [L]. min ,L max ], where L min It is the lowest brightness, L max That is the highest brightness; S5. Determine the range of human eye brightness sensitivity index: Based on ambient light intensity, the brightness distribution of the liquid crystal display, and the human eye's brightness sensitivity characteristics under bright field conditions, the range of the human eye brightness sensitivity index [γ] is determined. low ,γ up ], where γ low It is the lower limit exponent, γ up It is the upper limit index; S6. Dynamically adjust the grayscale index range of the LCD monitor: Based on the range of human eye luminance sensitivity index and its relationship with the grayscale index of the liquid crystal display, the grayscale index range of the liquid crystal display is dynamically adjusted [γ]. min ,γ max ], where γ min It is the minimum gray level index, γ min =1 / γ up ;γ max It is the maximum grayscale index, γ max =1 / γ low ; S7. Implement grayscale driving for the LCD display: Within the optimal grayscale voltage range of the LCD, the grayscale voltage is determined according to the number of grayscale bits and the grayscale index of the LCD, and the grayscale voltage is applied to drive the LCD to grayscale.

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

3. The method for dynamic grayscale adjustment of a liquid crystal display conforming to human eye brightness perception according to claim 1, characterized in that, The human eye's brightness sensitivity characteristics under bright field conditions are a mapping relationship between the brightness range and the human eye's brightness sensitivity index. The human eye's brightness sensitivity index is determined by the following steps: First, obtain the total brightness range [L0+L] of the sum of ambient light brightness and liquid crystal display brightness. 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 viewer's comfort level with grayscale cards of 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 grayscale cards that conform to human eye brightness perception under different sub-brightness ranges, and determine the upper and lower limits of their corresponding grayscale indices as the human eye brightness sensitivity index range [γ] for that brightness range. low ,γ up ].

4. The method for dynamic grayscale adjustment of a liquid crystal display conforming to human eye brightness perception according to claim 1, characterized in that, The grayscale depth of the liquid crystal display is ≥8 bits.

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