Backlight Brightness Research Articles

P‐36: Optimizing TV Gamma and Correlated Color Temperature Settings for Enhanced Viewer Satisfaction: A Comprehensive Study on Backlight Brightness and Color Gamut Influences

We investigate user acceptance of image quality across various TV configurations, highlighting the importance of customizing adjustments in gamma and correlated color temperature settings. The findings indicate that aligning these settings with TV performance can enhance the overall visual experience, closing the gap between technical standards and user preferences.

49‐4: Invited Paper: Super High Ambient Contrast LCDs with Low Power Consumption

The most effective way to improve display visibility in ambient light is to suppress the reflectance of the display. After conducting a thorough analysis of the factors contributing to unwanted reflection, specific layers were identified that required improvement. Subsequently, these elements were carefully optimized, resulting in a significant reduction of internal reflection to 0.53% for our 12.3” FFS‐mode prototype, compared to 1.12% in conventional LCDs. This improvement was achieved without the use of circular polarizers and has been demonstrated to provide excellent visibility in bright ambient conditions while allowing for reduced backlight brightness and lower power consumption.

11‐2: Optimizing TV Gamma Settings for Enhanced Viewer Satisfaction: A Comprehensive Study on Backlight Brightness and Color Gamut Influences

11‐2: Optimizing TV Gamma Settings for Enhanced Viewer Satisfaction: A Comprehensive Study on Backlight Brightness and Color Gamut Influences

P‐17.3: Visibility Research Based on Ambient Light Contrast

In the development process of displays, the viewer's experience is particularly important. However, in actual use, unlike the dark‐room test, there will be a certain amount of ambient light, which will affect the visibility of the display screen. As ambient illumination increases, the viewing effect of the display screen will also deteriorate. For example, it is difficult to see the screen clearly outdoors with bright sunlight, which is quite different from the viewing effect in dark room. In this article, we will study the visibility of public mode display and privacy mode display. For public mode display, both the central view angle and large view angle can see the screen clearly regardless of the ambient light brightness. For privacy mode display, no matter what the ambient light conditions are, it is invisible for the large view angle, while the center view angle can see clearly. And respectively propose two ways to improve the ambient contrast. In public mode, LCD with advanced reflective invisible technology with embedded system (ARIES) can achieve excellent visibility in various ambient light condition from indoors to outdoors without boosting the backlight brightness and sacrificing other performance for better visibility. In privacy mode, the view angle control cell (VAC) and privacy film are used to reduce the ambient light contrast of the privacy display, which fully satisfies the requirements of being invisible in the outdoor environment at a large view angle conditions, and can meet the privacy performance in some low ambient light. Author Keywords

Local Dimming Algorithm of Automotive LCD Instrument Based on Otsu and Maximum Entropy

In order to reasonably reduce the energy consumption of automotive LCD instrument and improve the display quality, a new local dimming algorithm is proposed in this paper. Firstly, the gray image of the input image is obtained by using the maximum principle, and then, the LED backlight brightness value is obtained by using Otsu method and maximum entropy method. The BMA backlight smoothing algorithm is improved by combining bilinear interpolation algorithm, and the dimming image is obtained by using pixel compensation algorithm based on logarithm. Then, for low brightness images, high brightness images, low contrast images, and high contrast images, typical algorithms are used to simulate and compare, and the image processing effects of various local dimming algorithms are analyzed. Finally, the entropy weight method is used to objectively evaluate the local dimming algorithm. The results show that the new local dimming algorithm reduces the energy consumption and improves the display quality, which verifies the effectiveness of the proposed algorithm.

P‐7.4: Adaptive content backlight and high brightness range control for RGBW arrangement of LCD panel

For improving LC light‐thru, the RGBW technology is proposed to implement peak brightness for high dynamic range display application. In current design, utilizing sub‐pixel rendering (SPR) places RGBW sub‐pixels on stripe array of 3 channels uniformly and keeps the same driving source line in three subpixels per pixel. The SPR algorithm is required to compensate it to pretend as similar display performance as real stripe RGB panel. The paper will discuss how W sub‐pixel is utilized to tune panel brightness and avoid possible issues for display colorful pictures. The paper would present the SPR, adaptive content backlight control (SPW+BL) and its HDR application (SPW+HDR) to dominate dynamic brightness range of RGBW panel.

17‐2: A method of improving image contrast based on Dual Cell display

Based on the Dual cell structure display, this paper proposes an effective contrast enhancement scheme. By using the lower cell to control the backlight brightness, local dimming is realized at the pixel level. Combined with spatial filtering, the ghosting problem of the Dual cell structure display is solved.

基于深度学习的区域背光亮度提取方法

基于深度学习的区域背光亮度提取方法

A rapid local backlight dimming method for interlaced scanning video

AbstractThis paper presents a rapid local backlight dimming method for interlaced video to improve the efficiency of displaying interlaced video. In the proposed method, we combine the line average deinterlacing algorithm with the local backlight dimming algorithm. In order to reduce the computational complexity and the backlight power consumption, three novel methods are proposed. The first is to add the sparse method to process the deinterlaced image. Second, the improved dynamic threshold method is used to calculate the dimming factor. And third, the odd field and even field of the same frame use the same backlight brightness to do backlight dimming. The simulation results show that the proposed method can reduce the computational complexity and power consumption, and the experiment results verify that the method can provide high display effect.

Multi-Block Gray Statistics Local Dimming Algorithm

Multi-block gray statistics local dimming algorithm is proposed to automatically control the brightness of the backlight for reducing energy consumption and enhancing the image quality. The large blocks are used to determine the value of backlight matrix and small blocks are to determine the image block brightness. With the use of BMA (Blur-mask approach) to blur the backlight brightness matrix and compensate LCD control signal, local dimming function is realized.The simulation results show that: for pictures, the average backlight power consumption is decreased markedly by 19.9% and the contrast ratio is increased by 53%.

基于图像分类的全局调光算法的FPGA实现

The traditional global dimming algorithm can not significantly improve the contrast and reduce power consumption.In view of this,a classification based on image global dimming algorithm is proposed.Using VHDL language in FPGA platform,this method is implemented according to the digital high-definition display timing logic and standard.This device can change 1 920×1 080 pixel HD video pixel data and backlight brightness at the same time,so as to significantly improve high-definition display resolution and reduce power consumption. Experimental results show that this device can meet the design targets,and have a good reliability,versatility,portability,and other characteristics.

Avoiding Conflicting Requirements: Development of Home Healthcare Devices Through an Interdisciplinary Approach

<i>Avoiding Conflicting Requirements:</i> Development of Home Healthcare Devices Through an Interdisciplinary Approach

고 효율 LED를 이용한 LCD 패널 구동회로의 설계 및 제작

LED가 의료장비용 LCD 패널의 광원으로 사용되는 경우, 밝기, 휘도 균일성, 고출력, 백색의 조절 능력, 온도 등을 고려한 우수한 광학 기구의 설계 및 제작이 필요하다. 본 논문에서는 휘도 및 균일도, dimming 범위의 증대, 잡음 발생 억제 등에서 측면발광 방식의 45인치 의료기기 등의 LED 후면광 시스템 및 구동회로를 설계하고 그 시제품을 제작하였다. 시제품의 휘도, dimming 범위, flicker 잡음, black level, 온도 특성 등을 측정한 결과, 휘도의 범위는 3,000 ~ 25,000[<TEX>$cd/m^2$</TEX>], 색 좌표는 x 좌표 0.3144, y좌표 0.3076의 평균값을 보였으며, 온도 특성은 휘도가 20,000[<TEX>$cd/m^2$</TEX>]이상의 제어에서 냉각 시스템이 필요한 것으로 나타났다. 한편, dimming의 범위는 27.0[<TEX>$cd/m^2$</TEX>] ~515[<TEX>$cd/m^2$</TEX>], flicker noise는 80kHz에서 발생하지 않았고, black level 0.7[<TEX>$cd/m^2$</TEX>]~0.1 [<TEX>$cd/m^2$</TEX>]를 얻어 의료기기 등의 LCD 패널에 적용할 수 있을 것으로 판단되었다. For using them as a optical source of inspections equipment for LCD panel, the design ofexcellent backlight system, brightness uniformity and high power and good protection against heat is essential.In this paper, backlight system which is built in the 45 inch side emitting LCD backlight by LED arraystructure and driving circuit were designed and developed. After that, their performances were measured. Itshowed the luminance from 3,000 to 25,000[<TEX>$cd/m^2$</TEX>], the mean value x:0.3144, y:0.3076 of x-y chromaticity,dimming range of 27~515[<TEX>$cd/m^2$</TEX>], free flicker noise in the 80kHz and black level of 0.7~0.1[<TEX>$cd/m^2$</TEX>], thermaltest of cooling system in 20,000[<TEX>$cd/m^2$</TEX>] over values.

Cooperative local dimming for accurate backlight brightness matching

A cooperative local dimming (CLD) method that effectively controls the brightness of the backlight unit is proposed. This CLD method takes into account the brightness of neighbouring light sources to achieve a backlight brightness that should be minimally higher than the brightness required by the pixels on the screen. The proposed CLD method matches pixel brightness more accurately and saves more energy than conventional local dimming methods do, thereby improving the quality of images and energy efficiency.

低功耗液晶电视LED背光源设计

A 118 cm(47 in) LED backlight was designed with reasonable selecting sheets and optimizing the mechanical structure.To ensure the brightness of backlight,a piece of diffusion sheet,two pieces of prism sheets and a piece of DBEF were combined.And the distance between LED and LED,the gap between LED and LGP,were determined by a series tests.Then according to the tests results,118 cm(47 in) LED backlight sample was assembled.Comparing with other products,the module has the lowest power consumption than others with the same optical performances.

A switched-capacitor PWM generator for LCD backlight brightness control

In this paper, a pulse width modulation (PWM) generator based on a switched capacitor for LCD backlight brightness control is described. The proposed scheme uses a simple RC network along with a clocked-comparator which samples the output of the ambient light sensor, and generates a PWM signal corresponding to the light level. Furthermore, by using a switched-capacitor resistor with variable clock frequency, the RC time constant is programmable and less sensitive to process variations with respect to passive resistors. In addition, it is shown that the linearity of the proposed PWM generator can be enhanced by replacing the RC network resistor with a constant current source. The operation of the PWM generator is verified through circuit level simulations, and the prototype circuit is fabricated using CMOS 0.18um technology.

모바일 제품의 효율적인 LCD 밝기 조절 기법에 관한 연구

There are a lot of multimedia functions getting included in mobile devices recently, not only simple audio but visual functions as well, such as video playing, game and web browsing. Such the visual multimedia functions brought the strong requirement for much bigger LCD Display and high resolution. And the brightness of LCD is also one of major requirements and it is required to be more bright. However, LCD brightness is limited to increase because of power consumption. It occupies nearly 30% of the whole system power. This thesis suggests an effective and simple method of adjusting the LCD backlight brightness, considering a characteristic of battery and user pattern.

Image integrity-based gray-level error control for low power liquid crystal displays

In this paper, we present a new approach to dynamic gray-level error control for global dimming of liquid crystal display (LCD) devices. In the LCD devices, global dimming is used to reduce power consumption by limiting the maximum luminance and lowering the brightness of backlight. The existing approaches, based on the fixed rate of clipped pixels, deteriorate the image quality seriously for some images even after gray level compensation. The proposed approach, on the other hand, dynamically chooses the maximum luminance for a given image, based on final image integrity. Thus, it has an advantage of preserving the worst image quality at any desired level, while reducing power consumption as much as possible. In the experiments, the proposed approach successfully maintained the minimum target peak signal to noise ratio (PSNR) for test sequences.

Locally pixel‐compensated backlight dimming on LED‐backlit LCD TV

Abstract— The pixel brightness of an LCD panel perceived by a user is the product of the backlight brightness and the panel transmittance. In conventional LCD panels, the backlight brightness is constant and always at peak luminance. This design suffers from light leakage and power waste problems at dark scenes. This paper presents a new LCD system, which uses locally pixel‐compensated backlight dimming (PCBD). The proposed method combines backlight control and pixel processing for reducing light leakage and power consumption while keeping the image at the original brightness. Backlight luminance is dimmed locally in the dark‐image region, and pixel values are compensated synchronously according to the luminance profile of dimmed backlight. By reducing the light leakage, a static contrast of over 20,000:1 has been achieved on a large‐sized LCD panel with the proposed PCBD method. No obvious artifacts have been noticed as well. The power consumption of the panel can also be greatly reduced, depending on various video content. The PCBD method could be widely used for developing state‐of‐the‐art LCD panels with LED backlights.

A coplanar hydrogenated amorphous silicon thin-film transistor for controlling backlight brightness of liquid-crystal display

We studied a coplanar hydrogenated amorphous silicon thin-film transistor (TFT) to control the backlight brightness in liquid-crystal display (LCD). This was done by designing the inverse-staggered TFT for the switching device and the coplanar TFT to absorb the illumination from backlight. We achieved the field-effect mobility of 0.3 cm 2/V s, threshold voltage of 3.6 V, and the subthreshold voltage swing of 1.3 V/d for the coplanar TFT. The TFT showed the photocurrent of ∼10 −8 A and dark current of ∼10 −11 A in the operation region of backlight for TFT–LCD. The dynamic range was 50 dB which is good enough to control the brightness of the backlight.