A contrast ratio and polarization compensation method for a mobile phone display panel without a polarizer
By employing electro-optic main axis orthogonal sub-pixels and a polarization compensation layer in the polarization-free mobile phone display panel, combined with factory calibration of the polarization state detection module and terminal compensation algorithm, the problems of black field light leakage and brightness fluctuation under ambient light are solved, achieving a display effect with high contrast and low power consumption.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JIANGXI JINLETONG TECH CO LTD
- Filing Date
- 2025-12-10
- Publication Date
- 2026-07-31
AI Technical Summary
Existing non-polarized mobile phone display panels, lacking an absorptive polarizer, suffer from issues such as large light leakage in black areas, low contrast, and inability to adjust polarization state in real time, leading to fluctuations in brightness and grayscale under ambient light.
By employing a first and second sub-pixels with mutually orthogonal electro-optic main axis orientations, combined with a polarization compensation layer and a polarization state detection module, grayscale values are adjusted in real time through factory calibration and terminal compensation algorithms to optimize contrast.
Significantly reduces black light leakage, improves white brightness and ambient contrast, maintains grayscale stability, improves light energy utilization efficiency, and reduces backlight power consumption.
Smart Images
Figure CN121640846B_ABST
Abstract
Description
[Technical Field] This invention relates to the field of display technology, and in particular to a method for contrast and polarization compensation of a polarizer-free mobile phone display panel. [Background Technology] Current mobile phone LCD panels typically have linear polarizers on the light-incident and light-out sides of the liquid crystal cell. These polarizers convert the natural light emitted by the backlight module into linearly polarized light, and the liquid crystal layer modulates the polarization state to control brightness and grayscale. The linear polarizer itself is an absorptive optical element, absorbing about half of the luminous flux, resulting in high backlight power consumption and heat generation, especially noticeable in outdoor high-brightness modes. Furthermore, the increased panel thickness hinders the design of ultra-thin devices.
[0001] To reduce or eliminate the light loss and cost associated with polarizers, the industry has proposed various polarizer-free or polarization-free display solutions. For example, by using special VA / TN orientations in conjunction with dye-based or polymer-dispersed liquid crystals, brightness and darkness can be achieved through absorption or scattering without the use of polarizers; alternatively, by using microlens arrays in conjunction with polarization-tunable liquid crystal layers, grayscale modulation can be achieved by changing the focal length and transmission pattern under different driving voltages. These solutions, while eliminating the need for polarizers, also improve transmittance to some extent and reduce power consumption.
[0002] However, in practical mobile phone applications, existing polarizer-free display solutions still have the following prominent problems: 1. In the absence of an absorptive polarizer, the liquid crystal layer or optical structure has limited ability to constrain the polarization state of ambient light and backlight, resulting in significant light leakage in the black field and a static contrast that is significantly lower than that of traditional polarized panels.
[0003] 2. Outdoor light, sky light, and indoor reflected light generally have different degrees of polarization components. The reflection and transmission of non-polarized display structures vary greatly for different polarization states, resulting in significant fluctuations in the brightness, grayscale, and contrast of the same image under different ambient light polarization states, leading to unstable user perception levels.
[0004] 3. Most existing polarizer-free displays rely on static optical designs, such as fixed orientation layers, fixed phase retardation films, and fixed scattering structures. They cannot sense the polarization state of the environment and lack closed-loop control that adjusts pixel polarization output and contrast in real time based on detection results.
[0005] 4. Current mobile phones generally integrate ambient light sensors, but they only adjust the backlight and Gamma curve according to the ambient brightness, without detecting the polarization information of the ambient light, and without performing grayscale and contrast compensation for polarization factors; without a polarizer structure, this control method that only considers light intensity is difficult to guarantee ambient contrast.
[0006] Therefore, without setting up an absorptive polarizer covering the effective display area, how to combine panel structure design, polarization state detection, and driving control algorithms to maintain a high and stable contrast under complex ambient light polarization conditions is a technical problem to be solved in this field. [Summary of the Invention] To overcome the above problems, this invention proposes a method for contrast and polarization compensation of a polarizer-free mobile phone display panel that can effectively solve the above problems.
[0007] The present invention provides a technical solution to the above-mentioned technical problems: a method for contrast and polarization compensation of a polarizer-free mobile phone display panel, applicable to a mobile phone display panel excluding an absorptive linear polarizer covering the effective display area. The mobile phone display panel includes a backlight module, a pixel unit array, a polarization compensation layer disposed on the light-emitting side of the pixel unit array, a polarization state detection module disposed on the front edge or punch-hole area of the display panel, and a display driving and control circuit. Each pixel unit in the pixel unit array includes at least a first sub-pixel and a second sub-pixel whose electro-optic principal axes are orthogonally oriented. The method includes the following indivisible chain of steps: Step S1, factory polarization calibration stage: Under controlled lighting conditions, the mobile phone display panel is controlled to display preset test patterns sequentially. The polarization state detection module collects multi-channel light intensity data corresponding to each test pattern under at least two mutually orthogonal analysis polarization directions. Based on the multi-channel light intensity data and the test pattern content, a correspondence is established between the display target brightness and the gray level combination of the first and second sub-pixels of each pixel unit. The environmental contrast evaluation model is used to select the gray level combination with better environmental contrast under different environmental conditions, generate a polarization compensation lookup table and store it in non-volatile memory. Step S2, initial grayscale allocation stage: During the terminal usage stage, when the image data to be displayed arrives, the display driving and control circuit reads the initial first grayscale value and the initial second grayscale value for each pixel unit from the polarization compensation lookup table according to the target brightness and target chromaticity of each pixel, and generates an initial grayscale frame. Step S3, the environmental polarization detection and contrast evaluation stage, within the preset sampling period, the mobile phone display panel is controlled to display a test block pattern at the position corresponding to the polarization state detection module. The polarization state detection module collects light intensity data under multiple analysis polarization directions, and estimates the comprehensive polarization state parameters after the current ambient light and the display output light are superimposed. The environmental contrast evaluation value is calculated by combining the ambient light illuminance, black field brightness and white field brightness. Step S4, orthogonal sub-pixel grayscale iterative compensation stage: Under the constraint that the user-perceptible brightness error and chromaticity error do not exceed the preset threshold, with the environmental contrast evaluation value as the optimization target, the initial first grayscale value and initial second grayscale value of each pixel unit are iteratively corrected at least once to obtain the first grayscale value and second grayscale value after polarization compensation, so that the light intensity of the black field pixel output light in the current environment main polarization direction is reduced, the brightness of the white field pixel is increased, and the grayscale transition is smooth. Step S5, the drive output stage, writes the first grayscale value and the second grayscale value after polarization compensation into the corresponding first sub-pixel and second sub-pixel, and modulates the polarization and intensity of the backlight module output light through the pixel unit and the polarization compensation layer, so as to improve the static contrast and ambient contrast of the display panel in the absence of a polarizer structure. Preferably, the environmental contrast evaluation model considers at least two of the following indicators simultaneously: Index 1: Average light leakage brightness in the black field region under different analytical polarization directions; Index 2: Average brightness of the white field region under different analytical polarization directions; Index 3: Brightness gradient difference between adjacent gray levels; Indicator 4: Brightness variation in different areas within the preset viewing angle range.
[0008] Preferably, the polarization state detection module includes multiple polarization selection units with different transmission axis directions and photosensitive units corresponding to each polarization selection unit. The included angle between the transmission axis directions of the multiple polarization selection units is 45 degrees or 90 degrees.
[0009] Preferably, the polarization state detection module is a chip-level polarization imaging sensor, including a polarization metasurface array integrated on the surface of a CMOS photosensitive array. The polarization metasurface array forms multiple sub-pixel units with different polarization analysis directions according to a predetermined pattern, which are used to acquire light intensity data of multiple polarization analysis directions within a single frame exposure.
[0010] Preferably, during the factory polarization calibration stage, by scanning different combinations of gray levels of the first and second sub-pixels on the black field test pattern, the gray level combination with the minimum light intensity in multiple analytical polarization directions is determined as the optimal black field compensation point, and the optimal black field compensation point is written into the polarization compensation lookup table.
[0011] Preferably, in the orthogonal sub-pixel grayscale iterative compensation stage: For pixel units whose target is black field, the output light intensity in the current environment's main polarization direction is reduced by decreasing the sum of the gray levels of the first sub-pixel and the second sub-pixel and adjusting the difference between them. For pixel units with a white field as the target, increase the brightness component in the main polarization direction of the current environment while keeping the color temperature and chromaticity within the set deviation. For mid-grayscale pixel units, the monotonicity of the grayscale brightness sequence is guaranteed first, and then the local contrast fluctuation is reduced on this basis.
[0012] A polarizer-free mobile phone display panel, comprising: Backlight module, used to provide unpolarized or partially polarized incident light; A pixel unit array is disposed on the light-emitting side of the backlight module. Each pixel unit in the pixel unit array includes at least a first sub-pixel and a second sub-pixel. The electro-optic principal axes of the first sub-pixel and the second sub-pixel are orthogonal to each other. The first substrate, the second substrate, and the electro-optic modulation layer sandwiched therein; A polarization compensation layer is disposed on the light-emitting side of the pixel unit array. The polarization compensation layer includes a phase delay microstructure layer and a scattering control layer, which are used to spatially correlate the polarization state and angular distribution of the output light of the pixel unit. The polarization state detection module is located on the front edge or cutout area of the display panel. It includes multiple polarization selection units with different light transmission axes and their corresponding photosensitive units, which are used to detect the light intensity of ambient light and display output light under multiple polarization analysis directions. Display driving and control circuitry for storing a polarization compensation lookup table and executing the contrast and polarization compensation method according to any one of claims 1 to 6; In particular, no absorptive linear polarizer covering the effective display area is set within the effective display area.
[0013] Preferably, the electro-optic modulation layer is a twisted nematic liquid crystal layer or a polymer-dispersed liquid crystal layer, and the phase delay microstructure layer is formed by a polymer material or nanostructure with anisotropic refractive index, and its optical axis is periodically or quasi-randomly distributed along the row and column directions.
[0014] Preferably, the scattering control layer includes a transparent substrate and scattering particles distributed in the transparent substrate. By controlling the particle size and concentration of the scattering particles, the display panel can maintain a high contrast within a preset viewing angle range and suppress glare at wide viewing angles.
[0015] A mobile phone terminal, characterized in that it includes a body and a polarizer-free mobile phone display panel as described in any one of claims 7 to 9, and further includes a main control processor and a memory electrically connected to the display panel, wherein the memory stores a computer program that can be executed by the main control processor, and the computer program, when executed, implements the contrast and polarization compensation method as described in any one of claims 1 to 6.
[0016] Compared with the prior art, the contrast and polarization compensation method of the polarizer-free mobile phone display panel of the present invention has the following beneficial effects: 1. By subdividing each pixel unit into a first sub-pixel and a second sub-pixel with mutually orthogonal electro-optic principal axis orientations, and combining the phase and scattering control of the polarization compensation layer, pixel-level degrees of freedom for adjusting the output polarization state are introduced without setting an absorptive linear polarizer covering the display area. Combined with environmental polarization detection and environmental contrast evaluation, black field light leakage can be significantly reduced and white field brightness and environmental contrast can be improved.
[0017] 2. A closed-loop system was constructed consisting of "polarizer-free pixel structure + polarization state detection module + factory polarization calibration lookup table + environmental contrast evaluation function + orthogonal sub-pixel grayscale iterative compensation". This system is a collaborative optimization of structure, detection and algorithm, and the overall contrast improvement effect is better than the simple superposition of each individual method.
[0018] 3. In the factory stage, the brightness and leakage characteristics of each pixel under different gray levels and polarization states are calibrated in detail using a standard light source and polarization detection module to form a high-dimensional polarization compensation lookup table; in the terminal stage, gray levels are fine-tuned according to the real-time environmental polarization state and environmental contrast evaluation value, so that relatively stable contrast and gray level performance can be maintained under different ambient lighting and polarization conditions.
[0019] 4. By eliminating the absorptive linear polarizer covering the display area, the light energy utilization efficiency is improved from a physical structure perspective. On this basis, the contrast is maintained through polarization compensation, which reduces backlight power consumption under the same visual performance requirements, thus improving the phone's battery life.
[0020] 5. The polarization state detection module can be implemented using a chip-level polarization imaging structure, which is small in size and thin in thickness, making it suitable for integration in the bezel or punch-hole area; the pixel substructure and polarization compensation layer can be adapted to existing display processes, and the engineering implementation path is clear. [Attached Image Description] Figure 1 This is a flowchart of the contrast and polarization compensation method for the polarizer-free mobile phone display panel of the present invention. Figure 2 This is a structural diagram of a polarizer-free mobile phone display panel, which is the method for contrast and polarization compensation in the polarizer-free mobile phone display panel of the present invention.
Detailed Implementation Methods
[0021] It should be noted that in the embodiments of the present invention, all directional indications (such as up, down, left, right, front, back, etc.) are limited to relative positions on the specified view, rather than absolute positions.
[0022] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.
[0023] The purpose of this invention is to provide a method for contrast and polarization compensation of a polarizer-free mobile phone display panel, as well as a corresponding display panel, mobile phone terminal and storage medium. Through the deep coupling of pixel structure design, polarization state detection module and contrast evaluation driving algorithm, without setting an absorptive linear polarizer covering the effective display area, the black field light leakage is significantly reduced, the white field brightness and grayscale stability are improved, thereby improving static contrast and ambient contrast, while taking into account high transmittance and low power consumption.
[0024] Please see Figure 1 and Figure 2 The present invention discloses a contrast and polarization compensation method for a polarizer-free mobile phone display panel, applicable to a mobile phone display panel excluding an absorptive linear polarizer covering the effective display area. The mobile phone display panel includes a backlight module, a pixel unit array, a polarization compensation layer disposed on the light-emitting side of the pixel unit array, a polarization state detection module disposed on the front edge or punch-hole area of the display panel, and a display driving and control circuit. Each pixel unit in the pixel unit array includes at least a first sub-pixel and a second sub-pixel whose electro-optic principal axes are orthogonally aligned. The method includes the following steps: 1. Factory polarization calibration stage: Under controlled lighting conditions, the display panel is controlled to sequentially display preset test patterns. The polarization state detection module collects multi-channel light intensity data corresponding to each test pattern under at least two mutually orthogonal analysis polarization directions. Based on the multi-channel light intensity data and the test pattern content, a correspondence is established between the display target brightness and the grayscale combination of the first and second sub-pixels of each pixel unit. The environmental contrast evaluation model is used to select the grayscale combination with better environmental contrast under different environmental conditions, generate a polarization compensation lookup table and store it in non-volatile memory.
[0025] 2. Initial grayscale allocation stage: During the terminal usage stage, when the image data to be displayed arrives, the display driver and control circuit reads the initial first grayscale value and the initial second grayscale value for each pixel unit from the polarization compensation lookup table according to the target brightness and target chromaticity of each pixel, and generates the initial grayscale frame.
[0026] 3. Ambient polarization detection and contrast evaluation stage: Within the preset sampling period, the display panel is controlled to display the test block pattern at the position corresponding to the polarization state detection module. The polarization state detection module collects light intensity data under multiple analytical polarization directions. Based on this, the comprehensive polarization state parameters after the current ambient light and the display output light are estimated. The ambient light illuminance, black field brightness and white field brightness are combined to calculate the ambient contrast evaluation value.
[0027] 4. Orthogonal sub-pixel grayscale iterative compensation stage: Under the constraint that the user-perceptible brightness error and chromaticity error do not exceed the preset threshold, with the environmental contrast evaluation value as the optimization target, the initial first grayscale value and initial second grayscale value of each pixel unit are iteratively corrected at least once to obtain the first grayscale value and second grayscale value after polarization compensation, so that the light intensity of the black field pixel output light in the current environmental main polarization direction is reduced, the brightness of the white field pixel is increased, and the grayscale transition is smooth.
[0028] 5. Driven output stage: The first grayscale value and the second grayscale value after polarization compensation are written into the corresponding first sub-pixel and second sub-pixel. The polarization and intensity modulation of the backlight module output light are performed through the pixel unit and the polarization compensation layer to improve the static contrast and ambient contrast of the display panel in the absence of a polarizer structure.
[0029] This invention also provides a polarizer-free mobile phone display panel, comprising: a backlight module for providing unpolarized or partially polarized incident light; a pixel unit array disposed on the light-emitting side of the backlight module, each pixel unit in the pixel unit array including at least a first sub-pixel and a second sub-pixel, the electro-optic principal axes of the first sub-pixel and the second sub-pixel being orthogonally oriented; a first substrate and a second substrate and an electro-optic modulation layer sandwiched therein; a polarization compensation layer disposed on the light-emitting side of the pixel unit array, the polarization compensation layer including a phase delay microstructure layer and a scattering control layer, for spatially correlated modulation of the polarization state and angular distribution of the output light of the pixel unit; a polarization state detection module disposed on the front edge or punch-hole area of the display panel, including multiple polarization selection units with different transmission axes and their corresponding photosensitive units, for detecting the light intensity of ambient light and display output light under multiple polarization analysis directions; and a display driving and control circuit for storing a polarization compensation lookup table and executing the above-mentioned contrast and polarization compensation methods; wherein, no absorptive linear polarizer covering the effective display area is disposed within the effective display area.
[0030] The present invention also provides a mobile phone terminal, including a body and the above-mentioned polarizer-free mobile phone display panel, and further including a main control processor and a memory electrically connected to the display panel. The memory stores a computer program that can be executed by the main control processor. When the computer program is executed, it implements the contrast and polarization compensation method.
[0031] The present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the contrast and polarization compensation method.
[0032] Specifically, the factory polarization calibration process includes the following steps: The first step is to connect the unpolarized mobile phone display panel to be calibrated to the testing equipment in a darkroom or standard lighting laboratory environment. Preset test patterns are displayed on the control panel via a standard backlight driver and display interface. These include pure black patterns, pure white patterns, multi-level grayscale patterns, and pure red, green, and blue patterns with different brightness levels. The test patterns can be divided into rows and columns to cover multiple locations on the panel.
[0033] The second step involves acquiring light intensity data in multiple analytical polarization directions during the display of each test pattern using a polarization state detection module. Light intensity can be acquired at analytical directions such as 0 degrees, 45 degrees, 90 degrees, and 135 degrees to estimate the transmission and reflection characteristics in different polarization directions.
[0034] The third step is to calibrate the polarization leakage characteristics of the display panel under the structure without a polarizer, based on the target brightness and chromaticity of the test pattern and the collected multi-channel light intensity data, and to establish the mapping relationship between the output brightness, polarization state and driving grayscale combination of each pixel and sub-pixel.
[0035] The fourth step involves introducing an environmental contrast evaluation model. Parameters such as black level brightness, white level brightness, ambient illuminance, and surface reflectivity are substituted into the model to calculate the environmental contrast under typical indoor and outdoor lighting conditions. Based on this, for each type of target brightness and chromaticity, combinations that achieve high environmental contrast, low black level leakage, and smooth grayscale transitions are selected from a variety of grayscale combination candidates, forming items in a polarization compensation lookup table.
[0036] The fifth step involves repeating the above process for pixel units of different colors, gray levels, and positions to finally generate a multi-dimensional polarization compensation lookup table indexed by target brightness, target chromaticity, pixel coordinates, and viewing angle category. This lookup table is then stored in the non-volatile memory of the display driver integrated circuit or the main control processor.
[0037] During the operation of the mobile terminal, the contrast and polarization compensation method of the present invention includes the following steps: The first step is initial grayscale allocation. After the main control processor receives the image frame data to be displayed, it calls the polarization compensation lookup table according to the target brightness and chromaticity parameters of each pixel in the image, reads the corresponding initial first grayscale value and initial second grayscale value for each pixel unit, generates an initial grayscale frame, and sends the frame to the display driver integrated circuit.
[0038] The second step is environmental polarization detection. Within a preset frame period, or when a significant change in ambient light is detected, the main control processor controls the display panel to display a test pattern at the corresponding position of the polarization state detection module. During the test, the polarization state detection module collects light intensity data of the ambient light and the displayed output superimposed in multiple analysis polarization directions. Based on this data, the main control processor calculates the dominant polarization direction, degree of polarization, and light intensity distribution in different analysis directions of the current environment.
[0039] The third step is environmental contrast evaluation. Based on the ambient illuminance, polarization state, and current image content, the main control processor uses an environmental contrast model to calculate the average brightness of the black area, the average brightness of the white area, the brightness gradient difference between adjacent gray levels, and the brightness uniformity within a preset viewing angle range, thereby obtaining the environmental contrast evaluation value.
[0040] The fourth step is orthogonal sub-pixel grayscale iterative compensation. Under the condition that the user-perceived brightness and chromaticity deviation thresholds are not exceeded, the main control processor uses the environmental contrast evaluation value as the optimization target and performs at least one iterative correction on the initial first grayscale value and initial second grayscale value of each pixel. For black areas, the grayscale difference between the first and second sub-pixels is mainly adjusted to reduce the main polarization direction component; for bright areas, the brightness component consistent with the main polarization direction is appropriately increased while maintaining color temperature and chromaticity; for mid-grayscale areas, the monotonicity of the grayscale brightness sequence is ensured and local contrast fluctuations are reduced.
[0041] The fifth step is drive output. The compensated first and second grayscale values are written into the display driver integrated circuit. The display driver integrated circuit outputs the corresponding pixel electrode voltage, driving the pixel unit and polarization compensation layer to perform polarization and intensity modulation on the backlight, completing the display of the current frame image. The above steps can be continuously and cyclically executed, enabling the non-polarized mobile phone display panel to maintain a high and relatively stable contrast under different environmental polarization conditions.
[0042] The polarizer-free mobile phone display panel of the present invention includes a backlight module 111, a first substrate 112a, a second substrate 112b, an electro-optic modulation layer 113, a pixel unit array 114, a polarization compensation layer 115, an encapsulation cover plate 116, a polarization state detection module 120, and a display driving and control circuit 130.
[0043] The backlight module 111 can adopt a direct-lit or side-lit structure. The light source can be an LED or Mini-LED array, and it can be used with optical films such as light guide plates, diffusion films, and brightness enhancement films to provide approximately uniform incident light. The light output by the backlight module does not pass through an absorptive linear polarizer covering the entire display area within the effective display area.
[0044] The electro-optic modulation layer 113 is sandwiched between the first substrate and the second substrate. It can be a twisted nematic liquid crystal layer, a vertically aligned liquid crystal layer, a polymer-dispersed liquid crystal layer, or other material layers that can generate phase modulation and scattering modulation of the polarization state of incident light. In this embodiment, it is preferably a liquid crystal structure that can achieve fast response.
[0045] Pixel unit array 114 is disposed on the light-emitting side of electro-optic modulation layer 113, and includes multiple rows and columns of pixel units. Each pixel unit includes three color sub-pixels: red, green, and blue. Each color sub-pixel is further divided into a first sub-pixel region and a second sub-pixel region. The initial alignment direction of liquid crystal molecules in the first sub-pixel region is along a first direction, for example, at a 45-degree angle relative to the X-axis of the glass substrate; the initial alignment direction of liquid crystal molecules in the second sub-pixel region is along a second direction orthogonal to the first direction, for example, at a 135-degree angle relative to the X-axis.
[0046] The first and second sub-pixel regions are electrically connected to their respective independent pixel electrodes. When the driving voltage changes, they produce different modulation effects on the phase delay and polarization state of the incident light. By combining and controlling the grayscale of the first and second sub-pixels, the equivalent polarization state of the output light can be adjusted while meeting the target brightness and chromaticity, thus achieving polarization compensation.
[0047] A polarization compensation layer 115 is disposed on the light-emitting side of the pixel unit array 114 and may include a phase retardation microstructure layer and a scattering control layer. The phase retardation microstructure layer can be formed by using a polymer material or nanostructure with anisotropic refractive index to create an optical layer with spatially varying optical axis direction and phase retardation, used to compensate for light rays with different incident angles and polarization states, and reduce viewing angle-related polarization crosstalk. The scattering control layer can limit light rays with excessively large incident angles by distributing scattering particles of a certain size and concentration in a transparent substrate, suppressing glare and improving contrast within the viewing angle range.
[0048] The polarization state detection module 120 is located in the front edge area of the display panel or the screen cutout area, and includes multiple polarization selection units with different transmission axis directions and corresponding photosensitive units. The polarization selection units can be micro polarization filters, linear polarization metasurface structures, or other micro / nano structures with polarization selectivity; the photosensitive units can be photodiodes or CMOS image sensor pixels. The transmission axis directions of the multiple polarization detection channels can be orthogonal to each other or at angles of 45 degrees, 60 degrees, etc., to obtain light intensity information of multiple analytical polarization directions.
[0049] The display driving and control circuit 130 includes a display driving integrated circuit and a main control processor. The display driving integrated circuit is electrically connected to the pixel electrodes and is used to generate corresponding pixel electrode driving voltages based on the first grayscale value and the second grayscale value provided by the main control processor. The main control processor is electrically connected to the polarization state detection module and the display driving integrated circuit, and is used to execute polarization compensation algorithms, environmental contrast evaluation, and polarization compensation lookup table calls.
[0050] The encapsulation cover 116 covers the front side of the display panel and can be made of glass or transparent polymer material. An anti-reflective or anti-fingerprint coating can be applied to its inner surface to reduce the contrast reduction caused by external reflection.
[0051] By not placing an absorptive linear polarizer covering the effective display area, the luminous flux utilization rate is improved.
[0052] The polarization state detection module can be implemented using a chip-level polarization imaging structure. This involves integrating a polarization metasurface array with different transmission axes onto the surface of a CMOS photosensitive array, allowing each micro-unit to selectively transmit incident light in different polarization analysis directions. By arranging multiple polarization selection units and photosensitive units according to a predetermined pattern, the intensity of light in multiple polarization directions can be measured within a single frame exposure. The polarization state of ambient light can then be obtained by solving for the Stokes parameters. This chip can be integrated near the front-facing camera module of a mobile phone or placed separately on the upper edge of the display panel or in the punch-hole area, without significantly occupying the effective display area.
[0053] This invention provides a mobile phone terminal including a body, a polarizer-free mobile phone display panel, a main control processor, a memory, a power management module, and a radio frequency module. The main control processor is electrically connected to a display driver integrated circuit and a polarization state detection module through a display interface, and implements the above-mentioned contrast and polarization compensation methods by executing a computer program in the memory.
[0054] Compared with the prior art, the contrast and polarization compensation method of the polarizer-free mobile phone display panel of the present invention has the following beneficial effects: 1. By subdividing each pixel unit into a first sub-pixel and a second sub-pixel with mutually orthogonal electro-optic principal axis orientations, and combining the phase and scattering control of the polarization compensation layer, pixel-level degrees of freedom for adjusting the output polarization state are introduced without setting an absorptive linear polarizer covering the display area. Combined with environmental polarization detection and environmental contrast evaluation, black field light leakage can be significantly reduced and white field brightness and environmental contrast can be improved.
[0055] 2. A closed-loop system was constructed consisting of "polarizer-free pixel structure + polarization state detection module + factory polarization calibration lookup table + environmental contrast evaluation function + orthogonal sub-pixel grayscale iterative compensation". This system is a collaborative optimization of structure, detection and algorithm, and the overall contrast improvement effect is better than the simple superposition of each individual method.
[0056] 3. In the factory stage, the brightness and leakage characteristics of each pixel under different gray levels and polarization states are calibrated in detail using a standard light source and polarization detection module to form a high-dimensional polarization compensation lookup table; in the terminal stage, gray levels are fine-tuned according to the real-time environmental polarization state and environmental contrast evaluation value, so that relatively stable contrast and gray level performance can be maintained under different ambient lighting and polarization conditions.
[0057] 4. By eliminating the absorptive linear polarizer covering the display area, the light energy utilization efficiency is improved from a physical structure perspective. On this basis, the contrast is maintained through polarization compensation, which reduces backlight power consumption under the same visual performance requirements, thus improving the phone's battery life.
[0058] 5. The polarization state detection module can be implemented using a chip-level polarization imaging structure, which is small in size and thin in thickness, making it suitable for integration in the bezel or punch-hole area; the pixel substructure and polarization compensation layer can be adapted to existing display processes, and the engineering implementation path is clear.
[0059] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any modifications, equivalent substitutions and improvements made within the concept of the present invention should be included within the patent protection scope of the present invention.
Claims
1. A method for contrast and polarization compensation in a polarizer-free mobile phone display panel, characterized in that, An absorptive linear polarizer is applied to a mobile phone display panel that does not cover the effective display area. The mobile phone display panel includes a backlight module, a pixel unit array, a polarization compensation layer disposed on the light-emitting side of the pixel unit array, a polarization state detection module disposed on the front edge or punch-hole area of the display panel, and a display driving and control circuit. Each pixel unit in the pixel unit array includes at least a first sub-pixel and a second sub-pixel whose electro-optic principal axes are orthogonally oriented. The method includes the following indivisible chain of steps: Step S1, factory polarization calibration stage: Under controlled lighting conditions, the mobile phone display panel is controlled to display preset test patterns sequentially. The polarization state detection module collects multi-channel light intensity data corresponding to each test pattern under at least two mutually orthogonal analysis polarization directions. Based on the multi-channel light intensity data and the test pattern content, a correspondence is established between the display target brightness and the gray level combination of the first and second sub-pixels of each pixel unit. The environmental contrast evaluation model is used to select the gray level combination with better environmental contrast under different environmental conditions, generate a polarization compensation lookup table and store it in non-volatile memory. Step S2, initial grayscale allocation stage: During the terminal usage stage, when the image data to be displayed arrives, the display driving and control circuit reads the initial first grayscale value and the initial second grayscale value for each pixel unit from the polarization compensation lookup table according to the target brightness and target chromaticity of each pixel, and generates an initial grayscale frame. Step S3, the environmental polarization detection and contrast evaluation stage, within the preset sampling period, the mobile phone display panel is controlled to display a test block pattern at the position corresponding to the polarization state detection module. The polarization state detection module collects light intensity data under multiple analysis polarization directions, and estimates the comprehensive polarization state parameters after the current ambient light and the display output light are superimposed. The environmental contrast evaluation value is calculated by combining the ambient light illuminance, black field brightness and white field brightness. Step S4, orthogonal sub-pixel grayscale iterative compensation stage: Under the constraint that the user-perceptible brightness error and chromaticity error do not exceed the preset threshold, with the environmental contrast evaluation value as the optimization target, the initial first grayscale value and initial second grayscale value of each pixel unit are iteratively corrected at least once to obtain the first grayscale value and second grayscale value after polarization compensation, so that the light intensity of the black field pixel output light in the current environment main polarization direction is reduced, the brightness of the white field pixel is increased, and the grayscale transition is smooth. Step S5, the drive output stage, writes the first grayscale value and the second grayscale value after polarization compensation into the corresponding first sub-pixel and second sub-pixel, and modulates the polarization and intensity of the backlight module output light through the pixel unit and the polarization compensation layer, so as to improve the static contrast and ambient contrast of the display panel in the absence of a polarizer structure.
2. The contrast ratio of the mobile phone display panel without polarizer and the polarizing compensation method according to claim 1, characterized in that, The environmental contrast evaluation model shall consider at least two of the following indicators simultaneously: Index 1: Average light leakage brightness in the black field region under different analytical polarization directions; Index 2: Average brightness of the white field region under different analytical polarization directions; Index 3: Brightness gradient difference between adjacent gray levels; Indicator 4: Brightness variation in different areas within the preset viewing angle range.
3. The method for contrast and polarization compensation of a polarizer-free mobile phone display panel as described in claim 1, characterized in that, The polarization state detection module includes multiple polarization selection units with different transmission axis directions and photosensitive units corresponding to each polarization selection unit. The included angle between the transmission axis directions of the multiple polarization selection units is 45 degrees or 90 degrees.
4. The method for contrast and polarization compensation of a polarizer-free mobile phone display panel as described in claim 3, characterized in that, The polarization state detection module is a chip-level polarization imaging sensor, including a polarization metasurface array integrated on the surface of a CMOS photosensitive array. The polarization metasurface array forms multiple sub-pixel units with different polarization analysis directions according to a predetermined pattern, which are used to acquire light intensity data of multiple polarization analysis directions within a single frame exposure.
5. The contrast ratio of the mobile phone display panel without polarizer and the polarizing compensation method according to claim 1, characterized in that, During the factory polarization calibration stage, different combinations of gray levels of the first and second sub-pixels are scanned on the black field test pattern to determine the gray level combination with the minimum light intensity in multiple analytical polarization directions as the optimal black field compensation point, and the optimal black field compensation point is written into the polarization compensation lookup table.
6. The contrast ratio of the mobile phone display panel without polarizer and the method of compensating for the polarization according to claim 1, wherein, In the orthogonal sub-pixel grayscale iterative compensation stage: For pixel units whose target is black field, the output light intensity in the current environment's main polarization direction is reduced by decreasing the sum of the gray levels of the first sub-pixel and the second sub-pixel and adjusting the difference between them. For pixel units with a white field as the target, increase the brightness component in the main polarization direction of the current environment while keeping the color temperature and chromaticity within the set deviation. For mid-grayscale pixel units, the monotonicity of the grayscale brightness sequence is guaranteed first, and then the local contrast fluctuation is reduced on this basis.
7. A mobile display panel without polarizer, characterized in that, include: Backlight module, used to provide unpolarized or partially polarized incident light; A pixel unit array is disposed on the light-emitting side of the backlight module. Each pixel unit in the pixel unit array includes at least a first sub-pixel and a second sub-pixel. The electro-optic principal axes of the first sub-pixel and the second sub-pixel are orthogonal to each other. The first substrate, the second substrate, and the electro-optic modulation layer sandwiched therein; A polarization compensation layer is disposed on the light-emitting side of the pixel unit array. The polarization compensation layer includes a phase delay microstructure layer and a scattering control layer, which are used to spatially correlate the polarization state and angular distribution of the output light of the pixel unit. The polarization state detection module is located on the front edge or cutout area of the display panel. It includes multiple polarization selection units with different light transmission axes and their corresponding photosensitive units, which are used to detect the light intensity of ambient light and display output light under multiple polarization analysis directions. Display driving and control circuitry for storing a polarization compensation lookup table and executing the contrast and polarization compensation method according to any one of claims 1 to 6; In particular, no absorptive linear polarizer covering the effective display area is set within the effective display area.
8. The mobile phone display panel without polarizer according to claim 7, wherein, The electro-optic modulation layer is a twisted nematic liquid crystal layer or a polymer-dispersed liquid crystal layer, and the phase delay microstructure layer is formed by a polymer material or nanostructure with anisotropic refractive index, and its optical axis is periodically or quasi-randomly distributed along the row and column directions.
9. The mobile phone display panel without polarizer according to claim 7 or 8, characterized in that, The scattering control layer includes a transparent substrate and scattering particles distributed in the transparent substrate. By controlling the particle size and concentration of the scattering particles, the display panel maintains a high contrast within a preset viewing angle range and suppresses glare at wide viewing angles.
10. A mobile terminal, characterized in that, The device includes a body and a polarizer-free mobile phone display panel as described in any one of claims 7 to 9, and further includes a main control processor and a memory electrically connected to the display panel. The memory stores a computer program that can be executed by the main control processor, and the computer program, when executed, implements the contrast and polarization compensation method as described in any one of claims 1 to 6.