Sharp Kabushiki Kaisha Corporation

Sharp Laboratories of America, Inc

The Secretary of State for Defence in Her Britannic Majesty's Government

Michiyuki Sugino

Takashi Yoshii

Makoto Shiomi

Takayoshi Yamaguchi

Toshiyuki Fujine

Yuji Kikuchi

Toshihiko Osada

Scott J Daly

Louis Joseph Kerofsky

John Clifford Jones

Takaji Numao

Takashi Kanda

Kyoji Kasuga

Shigetsugu Okamoto

Eiichi Takakura

Toshiaki Tabuchi

Eishi Oda

Alistair Graham

Masahiro Okui

Akiyoshi Nagawo

A liquid crystal display device in which a frame of the image signal to be displayed is written into a liquid crystal display panel while a backlight is activated intermittently within one frame period so as to prevent blur injury arising when displaying motion pictures includes: sections and for variably controlling the illumination duration of the backlight based on the detected type of the image content to be displayed. This configuration makes it possible to appropriately control the image quality degradation caused by blur injury, stroboscopic effect and flickering, hence realize total image quality improvement.

Liquid crystal display device

In general, when a user views an image displayed on a display apparatus, visual environments, such as ambient brightness, a distance from the user to the display apparatus and so on, may disadvantageously cause the image displayed on the display apparatus to become difficult to view. Moreover, it is complicated and troublesome for the user to enter information of ambient light amount and others when setting a picture quality. An image display apparatus holds both question constituent information related to visual environments and choice information serving as answers to questions constituted by the question constituent information, and further holds a plurality of picture quality control rules suitable for visual environments assumed in accordance with the choice information serving as the answers. When sensing a power-up, the image display apparatus outputs the questions; acquires result information that is choices serving as answers from the user to those questions and that is used to acquire the picture quality control rules; and controls the picture quality in accordance with the picture quality control rules acquired in accordance with the result information.

Image display apparatus

Embodiments of the present invention comprise systems, methods and devices for adjusting image code values in conjunction with display light source illumination levels for enhanced image display.

Methods and systems for image-specific tone scale adjustment and light-source control

An emphasis convertercompares the image data of the current vertical period with the image data of the previous vertical period and controls the input image data to a liquid crystal display panelbased on the emphasis conversion parameters stored in tables of ROMstoso as to achieve accelerated drive. A microcomputeris able to realize stable control of selecting emphasis conversion parameters by adding hysteresis to the detected temperature from a thermistoreven when the detected temperature fluctuates up and down crossing the temperature threshold.

Liquid crystal display

The device includes: a write-gray scale level determining means (), () for determining the write-gray scale level data for input image data that compensates the optical response characteristic of a liquid crystal display panel (), in accordance with, at least, the combination of the gray scale level transitions from a previous vertical period to a current vertical display period; and an achievable gray scale level determining means (), () for generating the achievable gray scale level data for input image data after a lapse of one vertical display period of the liquid crystal display panel, in accordance with, at least, the combination of the gray scale level transitions from one vertical display period to the next. The write-gray scale level determining means (), () determines the write-gray scale level data to be supplied to the liquid crystal display panel (), based on the achievable gray scale level data of the liquid crystal display panel (), corresponding to the input image data at the previous vertical display period, output from the achievable gray scale level determining means (), () and the input image data at the current vertical display period. In this way, it is possible to correctly inhibit generation of afterimages and present correct display of half gray scales even for motion pictures containing any kind of gray scale level transition, by implementing overshoot drive of the liquid crystal display panel using actual achievable gray scale levels within the one vertical display period, even if any type of gray scale level transition occurs from one vertical display period to the next.

An edge detecting circuit detects whether a particular pixel belongs to an edge by determining whether the differential value of the pixel from the neighboring pixel is equal to or greater than a threshold. Based on the detection result, an emphasis converter stops OS drive when the image of a pixel area is regarded as an edge image in accordance with the detected result of the edge detecting circuit and implements OS drive when the image of a pixel area is not regarded as an edge image. In this way, the edge detecting circuit detects edge portions of the input video, whereby OS drive in the emphasis converter can be controlled so as to be turned on and off.

Crystal display device

A liquid crystal display is constructed so that the representative gray scale levels are extracted and set at close intervals in the gray scale transition areas where the optical response characteristics of the LCD panel are poor while the representative gray scale levels are set at dispersed intervals in the gray scale transition area where the optical response characteristics of the LCD panel is relatively good, to thereby allot the selected representative gray scale levels to the addresses of the OS table. A write gray scale determining portion, referring to compensation signal data values stored in correspondence with the combinations of the respective representative gray scale levels, determines the write gray scale data to the LCD panel, whereby the optical response characteristics of the LCD panel can be compensated with high precision.

When reproducing an image by a display apparatus having a plurality of pixels, in an average signal level operation circuit is performed an operation to obtain an average signal level which is an average level of all the pixel signals in a picture signal including a pixel signal representing information of a pixel, then, according to this average signal level, in an input signal-output brightness property setting circuit is set an input signal-output brightness property representing variations in brightness of a pixel with respect to a level of the pixel signal, then, the compensation of the picture signal is performed either to satisfy the input signal-output brightness property thus set in a signal compensation section or to allow variations in maximum output brightness of a pixel of the display apparatus according to the average signal level in a maximum output brightness adjustment circuit, so as to output the picture signal subject to compensation to the display apparatus.

Image reproducing method, image display apparatus and picture signal compensation device

A liquid crystal display device capable of presenting to a viewer a high-quality video from the beginning of viewing the video on a liquid crystal display panel by heating the panel from a specified time earlier than a time preset to start the viewing. A liquid crystal display device for displaying a video on a liquid crystal display panel having a liquid crystal layer and electrodes for applying a data voltage to the liquid crystal layer is further provided with an inputting means for inputting time information for reserving viewing a video program and a heating means for warming the liquid crystal display panel for a specified period before the time preset to start the viewing. The period of warming the liquid crystal display panel is determined based on a working ambient temperature.

Liquid crystal display device having heater

A light modulating device, such as a ferroelectric liquid crystal display (FLCD) comprises an addressable matrix and modulating elements or pixels and associated circuitry for selectively addressing each element in a series of addressing frames in order to vary the transmission level of each element relative to the transmissions levels of the other elements. Such addressing utilises a temporal dither addressing scheme for addressing at least part of each element within each frame with different combinations of temporal dither signals applied to separately addressable temporal bits within the frame to produce different transmission levels. In order to enable a large number of grey levels to be produced whilst limiting the perceived errors at transitions between different grey levels, the temporal bits are addressed in a first order in a first frame (or in a first spatial location) and in a second order, which is different to the first order, in a second frame (or in a second spatial location). The order in which the temporal bits are addressed may be varied according to a prescribed sequence, for example alternating between successive frames, along each line or between corresponding frames on adjacent lines.

Light modulating devices

In an apparatus of digitally recording and reproducing video signals, when video signal data in one image frame is divided into a multiple-number of parts (N-parts) by dividing the image frame into N-divided rectangular regions and the N-parts of data are recorded on respective N tracks, each rectangular region is divided into blocks each having a multiple number of pixels and the thus generated blocks is subjected to a bit reduction coding operation. In recording the blocks, each of blocks are recorded onto a corresponding track in such a sequence that the blocks are scanned in a reciprocating manner along short-side directions of the rectangular region on the image frame. When the data is reproduced in a varied speed playback mode, the data are modified by every short-side row of blocks to thereby provide a high-quality playback picture at the varied speed.

Apparatus of digitally recording and reproducing video signals

An apparatus for selectively recording a baseband signal and a MUSE signal on a magnetic tape and for reproducing them at different speeds including: a magnetic head circuit having first and second groups of heads provided separately form each other. Each of the head groups includes four rotary heads for consecutively and helically scanning the tape to record and reproduce the baseband and MUSE signals. The apparatus further includes: an apparatus for providing a mode designating signal for designating an operational mode of the apparatus; a signal processing circuit which can process the baseband and MUSE signals, in response to the mode designating signal, for processing one of the baseband and MUSE signals; a head switching circuit for switching the connection between the signal processing circuit and the respective rotary heads in response to the mode designating signal; and a scanning speed adjusting circuit for adjusting the relative scanning speed of the rotary head and the recording tape in response to the mode designating signal. The apparatus can appropriately switch the scanning speed and the connection between the rotary heads and the signal processing circuit according to the type of signal and operational mode. Thus, the baseband signal is recorded as a two channel signal on the magnetic tape and the MUSE signal is recorded as a one channel signal. Also, the apparatus can reproduce the baseband and MUSE signals recorded according to the above-described track pattern at a different speeds, respectively.

Growing community of inventors

Chiba, Japan

Michiyuki Sugino