Direct Backlight Unit Research Articles

33‐3: An Autostereoscopic Display with Time‐Multiplexed Directional Backlight Using an Electroluminescent Display as a Light Source

We propose an autostereoscopic display with a directional backlight unit using an interleaved lens array and an organic electroluminescent display as an active light source. In the proposed system, the screen luminance per unit of power consumption is enhanced and the uniformity of luminance is improved.

63‐2: Nano‐wire Grid Polarizer and Meta‐surface Textures Integrated High Efficient and Single Polarized Light Emitting Diode

A low power consumption is an essential issue for all of the electrical products, especially for the wearable electrical products, and the liquid crystal displays. This manuscript proposed a single polarized light emitting diode (LED) chip which is used for a direct back light unit for LCD. A wire grid polarizer and a meta‐surface textures are set on the top and bottom of the LED chip in order to obtain a high polarization and transparency. After optimization the potential parameters, the transmittance of TM and the polarization are 93.71% and 99.3% respectively. It can replace the normal LED of direct back light unit in order to obtain a high efficiency of 20% improvement, by comparing liquid crystal display using the APF polarizer. It can be used for reducing power consumption and supply dependence, as well as the cost of displays.

89‐3: Late‐News Paper: High‐Efficiency and Polarized Light Emitting Diode with Wire Grid Polarizer and Meta‐surface Textures

A low power consumption is an essential issue for all of the electrical products, especially for the wearable electrical products, and the liquid crystal displays. This manuscript proposed a single polarized light emitting diode (LED) chip which is used for a direct back light unit for LCD. A wire grid polarizer and a meta‐ surface textures are set on the top and bottom of the LED chip in order to obtain a high polarization and transparency. After optimization the potential parameters, the transmittance of TM and the polarization are 93.71% and 99.3% respectively. It can replace the normal LED of direct back light unit in order to obtain a high efficiency of 20% improvement, by comparing liquid crystal display using the APF polarizer. It can be used for reducing power consumption and supply dependence, as well as the cost of displays.

Viewing zone expansion of a dual-viewer autostereoscopic display with inclined interleaved linear Fresnel lens arrays and a time-division quadruplexing directional backlight.

A novel autostereoscopic display with a directional backlight unit using a pair of inclined interleaved linear Fresnel lens arrays is designed and evaluated. Different high-resolution stereoscopic image pairs are provided to each of the two viewers simultaneously by applying time-division quadruplexing. The viewing zone is enlarged in the horizontal direction by inclining the lens array, which enables two viewers to have specific views corresponding to the positions of their own eyes without interfering with each other's view. Thus, two viewers with no special goggles on can share the same 3D world, which enables direct-manipulation style interaction and collaboration maintaining eye contact with each other.

P‐11.5: Design and Optimization Polarized Light Emitting Diode Chips with Nano‐Wire Grid Polarizer and Meta‐surface Textures

A low power consumption is one of the most important issue for all of the electrical products, especially for wearable products. This manuscript proposed a polarized light emitting diode (LED) chip which is used for a direct back light unit for LCD. A wire grid polarizer and a meta-surface textures are set on the top and bottom of the LED chip in order to obtain a high polarization ratio and transparency. After optimizing the potential parameters, the transmittance of TM and the polarization can reach up to 93.71% and 99.3% respectively. It can replace the normal LED in direct back light unit, and obtain an improved efficiency of 20%, when comparing liquid crystal display with a bottom APF polarizer. It can be used for reducing power consumption and supply dependence, as well as the cost of displays.

P‐65: Autostereoscopic Display for Two Viewers Providing Images Specific to Each Viewpoint

This paper proposes a novel autostereoscopic display with a directional backlight unit using a linear Fresnel lens array. In the proposed system, different stereoscopic image pairs can be provided to each of the two viewers simultaneously, and the viewing zone where two viewers can see the specific views for their own eyes without interfering with each other's view is enlarged.

Switching directional BLUs for full-resolution auto-stereoscopic 3D/2D and 2D/3D LCDs

Directional backlight unit (BLU) design concept was applied to realize full-resolution field alternate auto-stereoscopic liquid crystal displays (LCDs) with built-in 3D/2D and 2D/3D. The application-oriented BLU design requires priority in realizing 2D mode or 3D mode. The switching characteristic of BLU with two confronting illuminating sets was applied to build 2D mode into 3D display and 3D mode into 2D display. An LCD with 2D mode as primary function requires higher double-sided luminance uniformity than 3D mode. On the other hand, an LCD with 3D mode requires higher single-sided luminance uniformity than 2D mode. For increasing the double-sided luminance uniformity for 2D mode as a primary function of the display, the former BLU design was realized by using uniform prismatic structure, that is, using uniform bilateral prismatic structure with a cross section of isosceles triangle on the back surface of the light-guide plate. For increasing single-sided luminance uniformity for 3D mode as a primary function of the display, the latter was realized by using graded angle design, that is, unilateral prisms with a cross section of a scalene triangle on the back surface of the light-guide plate. The LCDs of small-sized-handheld game devices and still cameras were fabricated using the 3D/2D and 2D/3D displays.

Continuous Viewing Angle Distribution Control of Liquid Crystal Displays Using Polarization-Dependent Prism Array Film Stacked on Directional Backlight Unit

We present a polarization-dependent prism array film for controlling the viewing angle distribution of liquid crystal (LC) display panels without loss of light efficiency. On a directional backlight unit, our polarization-dependent prism array film, made into a stacked bilayer with a well-aligned liquid crystalline reactive mesogen (RM) layer on the UV-imprinted prism structure, can continuously control the light refraction function of the prism array by electrically switching incident polarization states of a polarization-controlling layer prepared by a twisted nematic LC mode. The viewing angle control properties of the polarization-dependent prism array film are analyzed under different prism angle and refractive index conditions of the RM layer. A simple analytic model is also presented to describe the intermediate viewing angle distributions with continuously varying applied voltages and incident polarization states.

60.4: Distinguished Paper: A Directional Backlight with Narrow Angular Luminance Distribution for Widening Viewing Angle of a LCD with a Front‐Surface‐Light‐Scattering Film

AbstractA directional backlight unit has been developed for widening the viewing angle of a TN‐LCD with a front‐surface‐light scattering film. The novel directional backlight has a diagonal of 34‐cm and is structured by light‐direction control micro features and an inverted prism film. The backlight has a round luminance cone of +/‐9 deg. and a uniform spatial distribution of 90%. In combination with the LCD, the narrow cone resulted in widening of the TN‐LCD's viewing angle up to 120 deg. FWHM.

Eliminating hotspots in a multi-chip LED array direct backlight system with optimal patterned reflectors for uniform illuminance and minimal system thickness

We propose an optical design process that significantly reduces the time and costs in direct backlight unit (BLU) development. In it, the basic system specifications are derived from the optical characteristics of RGB light-emitting diodes (LEDs) comprising the BLU. The driving currents are estimated to determine the theoretical RGB flux ratio for a desired white point. The number of LEDs needed to produce the target luminance is then calculated from the combined optical efficiencies of the components. Last, an appropriate array configuration is sought based on the illuminance distribution function for meeting the target uniformity. To showcase the design process we built two 42-inch triangular cluster arrays of 40 x 16 LED elements. When a flat reflective sheet was used, the minimum thickness required of the system to satisfy the target uniformity was 30 mm. Introducing a patterned reflective sheet removed hotspots that resulted from reducing the system thickness without the aid of additional optical components. Using an optimized patterned reflective sheet, reduction in system thickness as much as 5 mm was possible.

직하형 Back Light Unit에 사용하는 변형 막대프리즘의 1차원 배열로 구성한 새로운 BLU 필름

A new sheet of back light unit(BLU) to reduce the number of sheets and enhance the optical performances of direct back light unit(BLU) in a liquid crystal display is proposed and designed. In order to improve the straightness and spatial uniformity of brightness of the BLU, we design the new sheet with linear arrays of complicated bar prism by using the fusion of cylindrical lens and bar prism. Then, we investigate and analyze various optical performances of a BLU including the new sheet through an illumination optical system design program. From these results, we determine the optimum geometrical structure of the sheet. Under the optimum condition, the luminance efficiency and spatial uniformity of luminance of the BLU are 53.5% and 83.5% respectively. And the vertical and horizontal widths of the angular luminance distribution are and respectively. Finally we have fabricated a new BLU sheet according to this design shape by using an ordinary resins.