Showing papers on "Backlight published in 2012"
1 Jul 2012
TL;DR: A unified optimization framework, based on nonnegative tensor factorization (NTF), encompassing all tensor display architectures is introduced, which is the first to allow joint multilayer, multiframe light field decompositions and is also the first optimization method for designs combining multiple layers with directional backlighting.
Abstract: We introduce tensor displays: a family of compressive light field displays comprising all architectures employing a stack of time-multiplexed, light-attenuating layers illuminated by uniform or directional backlighting (i.e., any low-resolution light field emitter). We show that the light field emitted by an N-layer, M-frame tensor display can be represented by an Nth-order, rank-M tensor. Using this representation we introduce a unified optimization framework, based on nonnegative tensor factorization (NTF), encompassing all tensor display architectures. This framework is the first to allow joint multilayer, multiframe light field decompositions, significantly reducing artifacts observed with prior multilayer-only and multiframe-only decompositions; it is also the first optimization method for designs combining multiple layers with directional backlighting. We verify the benefits and limitations of tensor displays by constructing a prototype using modified LCD panels and a custom integral imaging backlight. Our efficient, GPU-based NTF implementation enables interactive applications. Through simulations and experiments we show that tensor displays reveal practical architectures with greater depths of field, wider fields of view, and thinner form factors, compared to prior automultiscopic displays.
495 citations
Patent•
22 Aug 2012TL;DR: A backlight assembly includes a light source unit, a reflective element, a receiving container and a diffusion plate as mentioned in this paper, which is used to reflect the light from the point light source toward an upper direction.
Abstract: A backlight assembly includes a light source unit, a reflective element, a receiving container and a diffusion plate. The light source unit has at least one point light source, and the point light source emits light toward a side surface direction. The reflective element has a reflective surface, and the reflective surface is separated from the point light source toward the side surface direction by a predetermined distance for reflecting the light from the point light source toward an upper direction. The receiving container has a bottom plate and a side wall, for receiving the light source unit and the reflective element. A diffusion plate is disposed over the light source unit and the reflective element. Thus, uniform brightness may be enhanced, and the thickness of a display apparatus may be reduced.
208 citations
Patent•
27 Apr 2012
TL;DR: In this paper, a light source with electroconductive section 19 on its ends, an optical shield 15 on the light-emitting side of the light source 17, and a light-shield cover which covers the end of the illumination device.
Abstract: FIELD: physics. ^ SUBSTANCE: disclosed illuminating device 12 comprises a light source 17 having an electroconductive section 19 on its ends, an optical shield 15 on the light-emitting side of the light source 17, and a light-shield cover which covers the end of the light source 17. The cover has a cover section 20z for covering the light source and an optical shield mounting section 20a on the light-emitting side of the cover section 20z for mounting the optical shield 15. There is a protruding section which protrudes from the optical shield mounting section 20a towards the centre of the light source 17. ^ EFFECT: design of a thinner liquid crystal display and design of a narrower frame for said device by improving overall illumination and increasing compensation for non-uniformity of illumination from the backlight device. ^ 9 cl, 8 dwg
147 citations
Patent•
10 Feb 2012
TL;DR: In this paper, a backlight unit and a display apparatus using the same backlight was described, where a first reflector, a second reflector partially having an inclined surface, a plurality of light sources disposed between the first and the second reflectors, and a third reflector disposed between adjacent light sources.
Abstract: A backlight unit and a display apparatus using the same are disclosed. The backlight unit includes a first reflector, a second reflector partially having an inclined surface, a plurality of light sources disposed between the first reflector and the second reflector, and a third reflector disposed between adjacent light sources.
137 citations
Patent•
16 May 2012TL;DR: In this article, the authors provided a liquid crystal display device, as well as a polarizer and a protective film suitable for the liquid-crystal display devices, which consisted of a backlight light source, two polarizers, and liquid crystal cell disposed between them.
Abstract: The invention provides a liquid crystal display device, as well as a polarizer and a protective film suitable for the liquid crystal display device. The liquid crystal display device comprises a backlight light source, two polarizers, and a liquid crystal cell disposed between the two polarizers; the backlight light source being a white light-emitting diode light source; each of the two polarizers comprising a polarizing film and protective films laminated on both sides of the polarizing film; at least one of the protective films being a polyester film having an adhesion-facilitating layer; the polyester film having a retardation of 3,000 to 30,000 nm; and the adhesion-facilitating layer comprising a polyester resin (A) and a polyvinyl alcohol resin (B).
135 citations
TL;DR: A novel current-balancing circuit for LED backlights with a smart combination of an inherent symmetry of circuit and capacitive balancing mechanism enables an efficient and cost-effective current balancing.
Abstract: One of the key challenges in driving multiple light-emitting-diode (LED) strings for a liquid-crystal-display (LCD) backlight system is to ensure uniform current control. Unequal current sharing between the strings is due to manufacturing spread and temperature variations. In this paper, a novel current-balancing circuit for LED backlights is proposed. A smart combination of an inherent symmetry of circuit and capacitive balancing mechanism enables an efficient and cost-effective current balancing. The operating principle of the proposed method is analyzed, and an appealing generalization is made. The feasibility of the proposed scheme is verified by developing a hardware prototype with a dimming feature to drive a 100-W edge-type backlight system, having six LED strings for a large-scale LCD panel.
103 citations
Patent•
24 Oct 2012
TL;DR: In this paper, an autostereoscopic display device consisting of a backlight plate, a display panel for displaying two-dimensional (2D) images or 3D images, a light splitting device for transmitting provided images in 2D mode and dividing incident images into right and left-eye images in 3D mode, and a polarization controller for rotating the vibration direction of light provided by the display panel at 90 degrees.
Abstract: The invention provides an autostereoscopic display device which comprises a backlight plate, a display panel for displaying two-dimensional (2D) images or three-dimensional (3D) images, a light splitting device for transmitting provided images in 2D mode and dividing incident images into right-eye images and left-eye images in 3D mode and a polarization controller The polarization controller is arranged between the display panel and the light splitting device, is used for rotating the vibration direction of light provided by the display panel in 2D mode at 90 degrees, and cannot change the vibration direction of the light provided by the display panel in 3D mode Autostereoscopic display is achieved by using the light splitting device and the polarization controller, and the problem of descending of backlight utilization rate in the prior art can be avoided effectively
92 citations
Patent•
16 Jun 2012TL;DR: In this paper, a system including a display surface, a directional backlight system configured to emit a beam of light from the display surface and a spatial light modulator configured to form an image for display via the directional back-light system is described.
Abstract: Embodiments are disclosed that relate to private video presentation. For example, one disclosed embodiment provides a system including a display surface, a directional backlight system configured to emit a beam of light from the display surface and to vary a direction in which the beam of light is directed, and a spatial light modulator configured to form an image for display via the directional backlight system. The system further includes a controller configured to control the optical system and the light modulator to display a first video content item at a first viewing angle and a second video content item at a second viewing angle.
86 citations
Patent•
6 Jun 2012
TL;DR: In this article, a liquid crystal display panel module, a backlight module, and a display device are described, which consists of a guide light plate, a light emitting assembly and a diffraction grating film.
Abstract: The invention discloses a liquid crystal display panel module, a backlight module and a liquid crystal display device. The liquid crystal display panel module comprises a liquid crystal display panel and a diffraction grating layer. The liquid crystal display panel is provided with multiple pixels. The diffraction grating layer is arranged on the liquid crystal display panel, and the maximum period of a grating of the diffraction grating layer is smaller than one tenth of the size of each pixel. The backlight module comprises a guide light plate, a light emitting assembly and a diffraction grating film. The light guide plate is provided with a light emitting surface and one or more light entering surfaces adjacent to the light emitting surface. The light emitting assembly is arranged besides the light entering surfaces. The diffraction grating film is arranged on the light emitting surface. Light provided by the light emitting assembly is emitted through the light emitting surface, passes through the diffraction grating and then is refracted towards the light emitting assembly. The liquid crystal display panel and the backlight module can be applied to the liquid crystal display device respectively or simultaneously.
57 citations
TL;DR: An eight-channel LED backlight driver that can improve conventional dimming control circuits for LCDs is presented and a dimming ratio of 50 000:1 is achieved with a 500-Hz PWM signal.
Abstract: The grayscale resolution of liquid crystal displays (LCDs) can be improved by modulating the grayscale of the pixels in LCDs or by dimming the LCD backlight source. Changing the voltage or turned-on time of a pixel to achieve high-resolution grayscale requires either an accurate digital-to-analog converter or a very high frequency pulsewidth modulation (PWM) signal, which increases hardware cost and power consumption. The fast transient response of light-emitting diodes (LEDs) makes them useful as a backlight source for improving the grayscale resolution of an LCD without additional overhead. This paper presents an eight-channel LED backlight driver that can improve conventional dimming control circuits for LCDs. The proposed design was fabricated in a TSMC 0.25-μm 60-V bipolar-CMOS-DMOS process, and the chip area is 2.7 mm2. A dimming ratio of 50 000:1 is achieved with a 500-Hz PWM signal. The maximum power conversion efficiency, including power consumption of the LED current regulators, is 89.3%, when the load is a 12 × 8 LED array, the input voltage is 20 V, and the LED current is set to 25 mA.
57 citations
Patent•
12 May 2012
TL;DR: In this paper, a stack of alternating high and low index dichroic material layers on the exit surface of a waveguide for a wedge type directional backlight was introduced, effectively reflecting the vast proportion of S-polarized light rays.
Abstract: By introducing a stack of alternating high and low index dichroic material layers on the exit surface of a waveguide for a wedge type directional backlight, natural reflectivity differences between polarized components can be increased, effectively reflecting the vast proportion of S-polarized light rays, while at the same time transmitting the P-polarized light rays, of light impacting the exit surface of the waveguide at an angle sufficient to exit the waveguide. This recovers polarization in wedge type backlight systems, increasing illumination exiting the waveguide. Also, on the back reflecting surface of the waveguide, a birefringent material can be added to efficiently transform S-polarized reflected light from the dichroic stack, into returning P-polarized light. Because returning rays that are now P-polarized by the birefringent material have already achieved the critical angle for exiting the waveguide, the rays transformed to P-polarization can now also exit the waveguide, increasing waveguide illumination.
Patent•
12 Mar 2012
TL;DR: In this paper, a light emitting diode (LED) is used as a light source of a backlight device and thermoelectric elements are provided in a chassis for holding the LED so as to surround the LLED.
Abstract: It is an object to manufacture a highly reliable backlight device with less color unevenness and less luminance unevenness, and a high-performance and highly reliable display device including the backlight device, which can display a high quality image. A light emitting diode (LED) is used as a light source of a backlight device and thermoelectric elements are provided in a chassis for holding the light emitting diode so as to surround the light emitting diode (the thermoelectric elements are provided under the light emitting diode and on the four sides thereof). A temperature in the backlight device is adjusted by cooling and heating by the thermoelectric elements.
Patent•
16 Sep 2012
TL;DR: In this paper, a backlight module is disclosed and a light guide plate is divided into many areas along a first direction perpendicular to the second side, and includes a plurality of mesh points disposed on the bottom surface, and the LEDs are disposed near the first, second, and third sides.
Abstract: A backlight module is disclosed The backlight module includes a frame body, a light guide plate disposed in the frame body, and a plurality of light emitting diodes (LEDs) The light guide plate includes a first, a second, and a third sides connected in sequence, and alight-emitting surface and a bottom surface which are opposite, wherein both of the angles between the first and the second sides and between the second and the third sides are larger than 90 degrees The light guide plate is divided into many areas along a first direction perpendicular to the second side, and includes a plurality of mesh points disposed on the bottom surface, and the LEDs are disposed near the first, the second, and the third sides Each of the areas has an illumination intensity distribution line disposed along a second direction which is perpendicular to the first direction, and densities of the mesh points on each of the areas vary with intensities on the illumination intensity distribution line on the same area When intensities are relative high, the densities of the mesh points are relative low When intensities are relative low, the densities of the mesh points are relative high
Patent•
16 Oct 2012TL;DR: In this article, a light source is arranged to selectively transmit light through the layers via the translucent portions to provide backlight for one or more elements integrated with fabric enclosure assembly, which may include representations of input keys and/or graphics associated with the fabric enclaves.
Abstract: Fabric enclosure backlighting techniques are described. In one or more implementations, one or more translucent portions are formed within a plurality of layers of a fabric enclosure assembly. In one approach, regions within one or multiple layers are laser etched to form the translucent portions within the fabric enclosure assembly. A light source is then arranged to selectively transmit light through the layers via the translucent portions to provide backlight for one or more elements integrated with fabric enclosure assembly. The one or more elements may include representations of input keys and/or graphics associated with the fabric enclosure assembly. The backlight may be used to view the one or more elements in low light and/or provide backlight effects such as borders, side lighting, labels, and so forth.
Patent•
18 Dec 2012TL;DR: In this article, a computing device is configured with a multifunctional backlit display and the backlighting can be operated in at least a first mode and a second mode, where the first mode provides luminance to the display so that images on the display can be easily seen.
Abstract: A computing device is configured with a multifunctional backlit display. The backlighting can be operated in at least a first mode and a second mode. In a first mode, the backlighting provides luminance to the display so that images on the display can be easily seen. In a second mode, the backlighting provides visual stimulus for relaying information to a user or a user's surroundings.
Patent•
6 Jul 2012
TL;DR: Improved apparatus and method for collecting and directing light from a source via a light guide and modulated display assembly in an efficient manner through the design and use of prismatic optical structures, diffusers and/or light redirectors as discussed by the authors.
Abstract: Improved apparatus and method for collecting and directing light from a source via a light guide and modulated display assembly in an efficient manner through the design and use of prismatic optical structures, diffusers and/or light redirectors.
TL;DR: A directional backlight unit has been developed to widen the viewing angle of a TN-LCD with a front-surface light-scattering film/layer and has a symmetrical round luminance cone and a uniform spatial distribution.
Abstract: — A directional backlight unit has been developed to widen the viewing angle of a TN-LCD with a front-surface light-scattering film/layer. The novel directional backlight has a diagonal of 34 cm and is structured by light-direction-control optical micro-features and an inverted prism film. The backlight has a symmetrical round luminance cone of ±9° and a uniform spatial distribution of 88%. By using this backlight unit in combination with an LCD, the narrow cone resulted in widening of the TN-LCD's viewing angle up to 120° at full width at half-maximum.
Patent•
13 Mar 2012TL;DR: In this article, the authors proposed a method to generate more readable modified images that are presented on electronic displays in bright ambient light, such as direct sunlight. But the modified images contain pixels that are either “on” or “off” and may be inverted to present a black on white background image on the display.
Abstract: Systems and method to generate more readable modified images that are presented on electronic displays in bright ambient light, such as direct sunlight. Images normally presented in lower ambient light are modified to generate modified images that have higher contrast and that contain less information. For example, modified images contain pixels that are either “on” or “off” and may be inverted to present a black on white background image on the display. Some information, such as text fields or icons, is removed from the modified image to increase readability in bright ambient light. A backlight level of the display is also able to be increased in bright ambient light.
Patent•
8 Oct 2012
TL;DR: In this paper, a flexible light diffusing waveguide is arranged to define a plurality of light-dwarfingering waveguide segments arranged substantially parallel to one another, and is coupled to at least one light source to provide flexible light panel suitable for general lighting purposes or for use as a backlight in a display, such as a video display.
Abstract: At least one flexible light diffusing waveguide is arranged to define a plurality of light diffusing waveguide segments arranged substantially parallel to one another, and is coupled to at least one light source to provide a flexible light panel suitable for general lighting purposes or for use as a backlight in a display, such as a video display. Multiple waveguides can be coupled to different color light sources to provide a multi-colored flexible backlight that is usable in combination with a flexible matrix-addressable panel to provide a flexible video display.
TL;DR: Experimental results show that the proposed method achieves low power consumption and little image distortion ratio simultaneously.
Abstract: In conventional liquid crystal display (LCDs), the backlight is set to maximum luminance regardless of the image which causes power waste and light leakage in the dark scenes. To circumvent these problems, the local dimming backlight is investigated. The algorithm based on details of the input image for the local dimming backlight in LCDs is proposed in this paper. Experimental results show that the proposed method achieves low power consumption and little image distortion ratio simultaneously.
Patent•
11 Jul 2012
TL;DR: In this article, the authors proposed a touch control display device consisting of a display module, a backlight module and a prismatic lens, which is used to improve the sensitivity of touch control.
Abstract: The invention relates to a touch control display device comprising a display module, a backlight module and a prismatic lens. The display module comprises a touch control sensing layer. The backlight module comprises a first light source, a second light source and a light guide plate. The first light source has a first wavelength and the second light source has a second wavelength which is less than the first wavelength. The light guide plate comprises a first incident light surface, a second incident light surface and an emergent light surface. The second incident light surface faces the emergent light surface and the first incident light surface is connected with the second incident light surface and the emergent light surface. The first light source is disposed on the first incident light surface and the second light source is disposed on the second incident light surface. The prismatic lens is disposed between the display module and the backlight module. According to the invention, the sensitivity of touch control is improved.
Patent•
31 Oct 2012TL;DR: In this paper, the mismatch between the isotropic nature of light emitted from the quantum dots and the light emitted directly from the light source can be alleviated by utilization of diffusers and prism sheets.
Abstract: Utilization of quantum dots in displays and the location of the quantum dot sheet within the stackup of the backlight can lead to issues such as non-uniform light mixing, non-uniform brightness, and off-axis changes in color. The mismatch between the isotropic nature of light emitted from the quantum dots and the light emitted directly from the light source can be alleviated by utilization of diffusers and prism sheets. The diffusers and prism sheets can be further utilized to change the angle of light such that it is directed upwards towards the top of the display for improved uniformity in brightness and enhanced performance. Placement of the diffuser sheets, prism sheets, and changes in the design of the components, such as the light guide path, can alleviate the issues by properly mixing the colors together in order to achieve a uniform distribution of colors in the display.
Patent•
3 Oct 2012
TL;DR: In this paper, a backlight module and a display device are provided, which can reduce electromagnetic interference of the backlight circuit and increase the efficiency of backlight source driver, which is used for manufacturing displays.
Abstract: The embodiment of the invention provides a backlight module and a display device, which can reduce electromagnetic interference of a backlight circuit and increase efficiency of a backlight source driver. The circuit comprises a plurality of LED (light-emitting diode) lamp bars, a plurality of crystal switches, the backlight source driver and a dimming controller. The embodiment of the invention is used for manufacturing displays.
Patent•
27 Jul 2012
TL;DR: In this article, a backlight module that includes a liquid crystal glass and a front frame is presented, where the front frame includes at most two side frame members that are opposite to each other.
Abstract: The present invention discloses a backlight module that includes a liquid crystal glass and a front frame. The front frame includes at most three successively-connected side frame members. The three side frame members are positionable on and hold down the liquid crystal glass. The present invention also discloses a backlight module, which includes a liquid crystal glass and a front frame, of which the front frame includes at most two side frame members that are opposite to each other. The two side frame members re positionable on and hold down the liquid crystal glass. The present invention also discloses a liquid crystal display device that uses the backlight module. The backlight module and the liquid crystal display device using the backlight module according to the present invention improve firmness of bonding between the liquid crystal glass and the front frame and lowers down cost of the backlight module.
Patent•
2 May 2012
TL;DR: In this paper, a backlight unit is provided which includes a light guide plate which guides incident light from a lateral side of the guide plate toward a liquid crystal display (LCD) panel placed in front of the light guide.
Abstract: A backlight unit is provided which includes: a light guide plate which guides incident light from a lateral side of the light guide plate toward a liquid crystal display (LCD) panel placed in front of the light guide plate; a light source unit which includes a light source which emits the light and a light source supporting member which supports the light source and is arranged adjacent to the lateral side of the light guide plate; a supporting frame which is arranged in the backlight unit; a quantum dot (QD) bar which is arranged between the lateral side of the light guide plate and the light source and changes a color of the light emitted from the light source; and a QD-bar fastening unit which fastens the QD bar to at least one of the light source supporting member and the supporting frame.
Patent•
13 Jun 2012
TL;DR: In this paper, a backlight module and a display device comprising the backlight are presented, and the luminance uniformities of the back light module and the display device are improved.
Abstract: The invention discloses a backlight module and a display device comprising the backlight module; wherein, the backlight module comprises a reflecting plate and a plurality of light sources. The reflecting plate possesses a reflecting surface, and the plurality of light sources are arranged on the reflecting surface, and emit facing the direction far away from the reflecting surface; wherein, the reflecting surface comprises a plurality of low reflecting parts of which the reflectivity is lower than that of other positions of the reflecting surface, the low reflecting parts are located in a region formed by the light sources and adjacent light sources. In the invention, the luminance uniformities of the backlight module and the display device comprising the backlight module are improved, and the bright piece phenomenon is also improved.
TL;DR: In this paper, the luminance and uniformity characteristics of a newly invented secondary optical lens, called the lightguide-diffusive component, which has a wide emission angle and is designed for thin direct LED backlighting applications, were examined.
Abstract: This study examines the luminance and uniformity characteristics of a newly invented secondary optical lens, called the “lightguide-diffusive component,” which has a wide emission angle and is designed for thin direct LED backlighting applications. The LED backlight module is composed of, at the very least, a light source, a secondary lightguide-diffusive component with a newly designed micro-structure having a reflective bottom surface, and a flexible printed circuit (FPC) for LED lighting. This lightguide-diffusive component modifies the emission profile of a single LED to provide better illumination and greater uniformity. The newly designed secondary optical lens module is shaped to cover the LED array, resulting in a more uniform spatial light energy distribution on the emission plane of the LED backlight. The uniformity ratio for the new design shows an increase of 24%, from 60% to 84%, and the luminance a 23.29% improvement, from 10 000 nits to 12 329 nits.
Patent•
18 Apr 2012
TL;DR: In this paper, a mobile display device driving apparatus and method which can reduce power consumption are disclosed, which includes a liquid crystal panel having a plurality of liquid crystal cells each formed in sub-pixel areas of four colors.
Abstract: A mobile display device driving apparatus and method which can reduce power consumption are disclosed. The driving apparatus includes a liquid crystal panel having a plurality of liquid crystal cells each formed in sub-pixel areas of four colors, a battery charged with a voltage, a power saving mode signal generator that detects the remaining power of the battery and generates a power saving mode signal based on the detected power to set a power saving mode of the liquid crystal panel. A controller sets a gain value in response to the power saving mode signal, converts external three-color input data into four-color data based on the set gain value and generates a dimming signal in response to the power saving mode signal. A panel driver displays an image based on the four-color data on the liquid crystal panel. An inverter generates a lamp drive voltage based on the dimming signal, and a backlight unit generates light in response to the lamp drive voltage and irradiates the generated light to the liquid crystal panel.
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TL;DR: This paper shows both static, printed tensor displays, and dynamic LCD-based systems, providing wide field-of-view, bright, high-resolution, glasses-free 3D display, and introduces a unified optimization framework, based on nonnegative tensor factorization (NTF), encompassing all tensor display architectures.
Abstract: We introduce tensor displays: a family of light field displays comprising all stacked display architectures employing light-attenuating layers illuminated by uniform or directional backlighting (i.e., any low-resolution light field emitter). Tensor displays include the capability to time-multiplex content across frames on each of the layers to improve image quality. We show that the light field emitted by an N-layer, M-frame tensor display can be represented by an Nth-order, rank-M tensor. In a related technical paper submission, we use this representation to introduce a unified optimization framework, based on nonnegative tensor factorization (NTF), encompassing all tensor display architectures (see supplementary supporting document). In this emerging technologies demonstration, we show both static, printed tensor displays, and dynamic LCD-based systems, providing wide field-of-view, bright, high-resolution, glasses-free 3D display.
Patent•
10 May 2012
TL;DR: In this article, an apparatus for providing a dimensional display such as a 3D effect without special-purpose glasses is described. The apparatus includes a foreground display assembly including a first planar display element with a front surface and an opposite back surface.
Abstract: An apparatus for providing a dimensional display such as a 3D effect without special-purpose glasses. The apparatus includes a foreground display assembly including a first planar display element with a front surface and an opposite back surface. Additionally, the apparatus includes a background display assembly including: (a) a second planar display element spaced apart from and parallel to the first planar display element; and (b) a light source backlighting a back surface of the second planar display element. The first and second display elements are emissive display units and concurrently display frames of a foreground image stream and corresponding frames of a background image stream. The first display element may be a transparent LCD panel, and the output light from the front surface of the second display element provides backlighting for the first display element such that foreground images are backlit by output light of the second display element.