CN-122018194-A - Liquid crystal display device and method for improving low-visual-angle bluish violet and background color devitrification

Abstract

The invention discloses a liquid crystal display device and a method for improving low-visual-angle bluish violet and ground color polarization, wherein the liquid crystal display device comprises an upper polarizer, a liquid crystal box, a lower polarizer and a backlight module which are sequentially stacked, the liquid crystal box is a vertical alignment type liquid crystal box, the box thickness of a liquid crystal layer in the liquid crystal box is 3.2-3.8 mu m, the upper polarizer and the lower polarizer are combined by adopting a wide-visual-angle low-color polarization sheet, and a light-focusing type brightness enhancement film layer is arranged in the backlight module and is used for gathering light around a backlight towards the center of a display area so as to compensate optical path difference unbalance caused by liquid crystal molecule inclination under a low visual angle. The invention can eliminate the low-visual-angle background color cast and bluish violet of the VA type LCD through a synergistic system of box thickness optimization, polaroid adaptation and brightness enhancement film light field regulation, and has the advantages of both process yield and high contrast ratio.

Inventors

• FENG WEIBIN
• HE XIAOJUN
• TU YUJUAN

Assignees

• 东莞明崴电子科技有限公司

Dates

Publication Date

20260512

Application Date

20260319

Claims (10)

1. 1. A VA/MAV type liquid crystal display device for improving low-visual-angle bluish violet and ground color devitrification is characterized by comprising an upper polaroid, a liquid crystal box, a lower polaroid and a backlight module which are sequentially laminated; the liquid crystal box is a vertical alignment type liquid crystal box, and the thickness of a liquid crystal layer in the liquid crystal box is 3.2-3.8 mu m; the upper polaroid and the lower polaroid are combined by adopting a wide-viewing angle low-color-polarization sheet; The backlight module is internally provided with a light-focusing type brightness enhancement film layer, and the light-focusing type brightness enhancement film layer is used for gathering light rays around the backlight towards the center of a display area so as to compensate unbalanced optical path difference caused by inclination of liquid crystal molecules under a low visual angle.
2. 2. The VA/MAV-type liquid-crystal display device of claim 1, wherein the pixel units of the liquid-crystal cell adopt a multi-domain division structure, a single pixel unit is divided into a plurality of sub-domains, liquid-crystal molecules in each sub-domain face different preset directions in an energized state, and light characteristics of the different sub-domains are complementary under a squint angle.
3. 3. The VA/MAV-type liquid-crystal display device of claim 1, wherein the cell thickness of the liquid-crystal layer is 3.5 μm.
4. 4. The VA/MAV-mode liquid-crystal display device according to claim 1, wherein the light-collecting type brightness-enhancing film layer is a prism-type brightness-enhancing film, and a light-collecting surface of the prism-type brightness-enhancing film is disposed toward a side of the liquid-crystal cell.
5. 5. The VA/MAV mode liquid crystal display device of claim 4, wherein the prism-shaped brightness enhancement film has a luminance gain factor of 1.55 to 1.90.
6. 6. The VA/MAV-type liquid crystal display device of claim 1, wherein the wide-viewing angle low-color-deviation-polarization-plate combination has an applicable temperature range of-40 ℃ to 80 ℃ and a side-viewing angle base color of black.
7. 7. A method for improving low-visual-angle bluish violet and background color cast of a VA/MAV type LCD is characterized by comprising the following steps: S1, adjusting the thickness of a liquid crystal layer of a VA/MAV type vertical alignment liquid crystal box to 3.2-3.8 mu m, and reducing optical path difference fluctuation caused by liquid crystal molecule inclination under a low visual angle; S2, polaroid adaptation, namely selecting a wide-view low-color polarization sheet combination matched with the thickness parameters of the adjusted box, and respectively attaching the combination to the light emitting side and the light entering side of the liquid crystal box; S3, light field regulation and control, namely adding a light-focusing type brightness enhancement film layer in the backlight module, gathering light lines around the backlight to the center of a display area through the light-focusing type brightness enhancement film layer, compensating unbalance of optical path difference under a low visual angle, and eliminating the phenomena of background color devitrification and bluish violet under the low visual angle.
8. 8. The method according to claim 7, wherein in the step S3, the light-collecting type brightness enhancement film layer is a prism type brightness enhancement film, and the light-collecting surface of the prism type brightness enhancement film is directed to the liquid crystal cell side when the prism type brightness enhancement film layer is provided, and the luminance gain coefficient of the prism type brightness enhancement film is controlled to be 1.55-1.90.
9. 9. The method of claim 7, further comprising the step of optimizing the pixel structure by performing multi-domain division on the pixel units of the liquid crystal cell, dividing a single pixel unit into a plurality of sub-regions, enabling the liquid crystal molecules in each sub-region to face different preset directions in the power-on state, and compensating for color shift under the oblique viewing angle through the light characteristics of the different sub-regions.
10. 10. The method according to claim 7, wherein in the step S1, the thickness of the liquid crystal layer of the VA/MAV type liquid crystal cell is precisely adjusted to 3.5 μm.

Description

Liquid crystal display device and method for improving low-visual-angle bluish violet and background color devitrification Technical Field The invention relates to the technical field of liquid crystal display, in particular to a liquid crystal display device and a method for improving low-visual-angle bluish violet and ground color devitrification. Background Liquid Crystal Displays (LCDs) are currently the mainstream flat panel display devices, in which vertical alignment (VA/MAV) LCDs are widely used in scenes with high display quality requirements such as vehicle-mounted display, industrial control, high-end consumer electronics, etc. by virtue of the core advantages of high contrast ratio, low dark state light leakage, and good color reproducibility. However, VA/MAV LCD is limited by the inherent characteristic of vertical alignment of its own liquid crystal molecules, and when viewing at low viewing angle, the inclination of the liquid crystal molecules causes unbalanced optical path difference, which results in the phenomena of background color devitrification and bluish violet on the display screen, severely degrading the display contrast and viewing effect at low viewing angle, and becoming a core technical bottleneck for restricting the large-scale application of VA/MAV LCD in full viewing angle display scene. CN108287422a discloses a special-shaped liquid crystal display screen, which adopts a surface polarizer, a liquid crystal box, a bottom polarizer and a backlight plate structure which are sequentially laminated, the transmittance of the device is improved by adopting an ultrathin ITO glass substrate, an optical compensation film is additionally arranged on the bottom polarizer to widen the conventional visual angle, and meanwhile, the combination of a reflective polarizing brightness enhancement film and an ultra-micro polycrystalline structure brightness enhancement film is arranged in the backlight plate to improve the overall brightness of the backlight, so that the performance optimization of high transmittance, high contrast and wide viewing angle of the display screen is finally realized. CN108227282a discloses a high uniformity thin liquid crystal display, which further precisely controls thickness parameters of a brightness enhancement film on the basis of the above laminated structure, increases distance between the edge of a light guide plate and TFTAA area to reduce edge reflection, and increases PS supporting structure through a light alignment process and BM area to improve structural stability of a liquid crystal box, so as to solve the defects of poor uniformity and larger thickness of devices of the traditional LCD, and realize high uniformity, thinning and wide viewing angle characteristics of the display. The prior art has the following core defects and limitations, and cannot solve the technical problems of low-visual-angle background color devitrification and bluish violet of the VA/MAV type LCD: First, the above-mentioned prior art is optimized for the general performance (light transmittance, picture uniformity, overall device thickness, and conventional wide viewing angle characteristics) of the general TFT-type LCD or the special-shaped screen, and does not pay attention to the problems of low viewing angle background color bias and bluish violet exclusive caused by the inherent vertical alignment characteristics of the liquid crystal molecules of the VA/MAV-type LCD, nor does it implement the corresponding technical design for the core cause of the problems, so that the display defects cannot be fundamentally improved. Second, the wide viewing angle optimization in the prior art realizes the improvement of brightness and contrast ratio in the conventional viewing angle range only through the optical compensation film and the brightness enhancement film, can not inhibit the problems of color shift drift and ground color permeation in the low viewing angle, and has very limited effect of improving the low viewing angle display defect of the VA/MAV type LCD. In summary, the prior art has not proposed a technical solution for effectively solving the problems of low-viewing-angle background color transmission and bluish violet of the VA/MAV LCD, and cannot improve the display effect under the low viewing angle of the VA/MAV LCD on the premise of guaranteeing the original performance advantages of the VA/MAV LCD, so that development of a corresponding technical solution is needed to fill the blank of the prior art and meet the application requirements of the VA/MAV LCD in the full-viewing-angle display scene. Disclosure of Invention The technical problem to be solved by the invention is to provide a liquid crystal display device and a method for improving low-visual-angle bluish violet and undertone transmission, which can eliminate the low-visual-angle undertone transmission and bluish violet of a VA type LCD by a synergistic system of box thickness optimization, polaroid