JP2008064971A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively attain low power consumption without lowering view quality by switching to a low-power-consumption mode. <P>SOLUTION: A transmission type liquid crystal display device has a switching means 3 of switching to the mode of low power consumption, and upon the switching of the switching means, the lightness 5 of a back light, whether a choice of use of an image processing circuit 2, for example, an edge correction processing circuit is correct, and output sound volume 4 are controlled respectively. A stage of lightness of the back light, a choice of which of a plurality of image processing circuits is used, and a stage of the output sound volume are controlled respectively, so that the extent of the power consumption mode is switched step by step. In addition, a distance measuring sensor which measures the view distance between the liquid crystal display device and a user is included, and the lightness of the back light etc., is controlled according to the measured view distance. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to reduction of power consumption in a liquid crystal display device, and more particularly to a technique for reducing power consumption by switching a low power consumption mode (also referred to as an energy saving mode).

  A liquid crystal display device is often used as one of the display means of a thin display device. In a digital television display device such as a liquid crystal television display device, various types such as I / P conversion, edge enhancement, and noise removal are provided. Image quality is improved by a circuit using image processing technology.

  In addition, consideration for the environment such as global warming due to carbon dioxide emission is regarded as important, and there is a strong demand for reducing power consumption in liquid crystal display devices.

As a conventional technique for reducing power consumption of a liquid crystal display device, a method of controlling a backlight by turning off an unnecessary part of a light source (see, for example, Patent Document 1), and power consumption by selecting an image processing circuit A method (for example, refer to Patent Document 2) for reducing the number has been proposed. For example, as disclosed in Patent Document 3, a method of reducing power consumption by switching the brightness of a backlight between a television image and a computer image has been proposed.
JP-A-10-207400 JP-A-2005-192134 JP 2006-11366 A

  However, in recent years, demands for reducing power consumption in consideration of the global environment have become stricter, and further reduction of power consumption has been demanded. In the prior art disclosed in the above-mentioned Patent Documents 1, 2, and 3, power consumption control is performed due to partial turn-off of the backlight or different power supply sources and input images. The problem of being reduced occurs.

  Also, the viewing distance of the viewer is not taken into consideration, and it is generated by performing a bright display that the viewer does not need, an output volume that is larger than necessary, and excessive image processing in a situation that does not place importance on image quality. Response to wasteful power consumption was not considered.

  An object of the present invention is to provide a liquid crystal display device that can effectively reduce power consumption without degrading viewing quality by switching to a low power consumption mode.

In order to solve the above problems, the present invention mainly adopts the following configuration.
The transmissive liquid crystal display device has switching means for switching to a low power consumption mode, and by switching the switching means, the use of an image processing circuit as an example of backlight brightness and edge correction processing circuit is appropriate. The output volume is controlled individually.

  Further, the transmissive liquid crystal display device includes a distance measuring sensor for measuring the viewing distance of the liquid crystal display device and the user, and an example of backlight brightness and edge correction processing circuit according to the measured viewing distance. Whether to use or not to use the image processing circuit and to control the output volume.

  According to the present invention, under the condition that the viewing quality is not changed by switching to the energy saving mode (hereinafter referred to as the energy saving mode), the brightness of the backlight is reduced, the output volume is lowered, and the image processing circuit is partially stopped, It is possible to finely limit the power consumed by the device.

  In addition, in order to maintain viewing quality, step-by-step mode control of the energy saving mode is performed based on the distance information between the user and the liquid crystal display device, eliminating unnecessary power consumption and realizing power consumption control in a state suitable for viewing. can do.

  A liquid crystal display device according to an embodiment of the present invention will be described in detail below with reference to FIGS. FIG. 1 is a block diagram showing the overall configuration of a liquid crystal display device according to an embodiment of the present invention. FIG. 2 is a flowchart showing a procedure for generating a control signal for reducing power consumption in the energy saving mode in the liquid crystal display device according to the present embodiment. FIG. 3 is a diagram illustrating the viewing distance between the liquid crystal display device according to the present embodiment and the viewer. FIG. 4 is a flowchart showing the energy saving setting items in the energy saving mode based on the viewing distance shown in FIG. FIG. 5 is a diagram showing setting values of each item of backlight luminance, output volume, and image processing circuit selection when the energy saving mode in the liquid crystal display device according to the present embodiment is changed stepwise.

  First, the characteristics of the liquid crystal display device according to the embodiment of the present invention will be outlined. This embodiment includes a switching unit that switches to an energy saving mode that reduces power consumption, and the brightness control of the backlight is performed by switching to the energy saving mode. The image processing circuit selection control and the output volume control reduce power consumption. The energy-saving mode is controlled by the user's operation and the viewing distance between the viewer and the liquid crystal display device. This is a liquid crystal display device that performs switching.

  In the overall configuration of the liquid crystal display device according to this embodiment shown in FIG. 1, 1 is an image signal processing unit, 2 is an image processing selection control unit, 3 is an energy saving mode switching unit, 4 is an audio output control processing unit, and 5 is a back. A light control unit, 6 represents a display device, and 7 represents a speaker.

  First, when the energy saving mode switching unit 3 switches to the energy saving mode (which will be described later, an operator's instruction, a control instruction based on viewing distance detection, a control instruction from another component), the backlight control unit 5 uses the display device 6. A control signal for lowering the luminance of the backlight is generated, and the control signal is transmitted to the display device 6 having the backlight. The image processing selection control unit 2 also controls a control signal for selecting an image processing circuit to be used in the image signal processing unit 1 (which will be described later, for example, bypasses processing circuits such as edge correction and noise removal in the image processing circuit. And a video signal processed by the selected image processing circuit is output to the display device. Further, the audio output control unit 4 generates a control signal for reducing the output volume, and the controlled audio is output from the speaker 7.

  A combination of a control signal for reducing backlight luminance, an image processing signal to be used, and a control signal for selecting a control signal for reducing the output volume reduces power consumption in an optimum viewing environment desired by the user.

  Next, each control signal generation in the energy saving mode for reducing power consumption will be described with reference to the flowchart of FIG. Switching of the energy saving mode (step S1) is performed by a switching by a user instruction or a switching control signal from another block. When the mode is switched to the energy saving mode, if there is an instruction to reduce power consumption by backlight control, the backlight luminance is reduced (step S2). Further, when there is an instruction to reduce power consumption by volume control by switching the energy saving mode, control to set to the designated output volume is performed (step S3). When the mode is switched to the energy saving mode and there is an instruction to select an image processing circuit to be used in step S4, image processing selection control is performed. Power consumption can be reduced in a stepwise manner by a combination of the luminance, volume, and image quality processing circuit selection.

  Next, energy saving control based on the viewing distance between the liquid crystal display device and the viewer will be described below. FIG. 3 is a diagram showing the viewing distance between the liquid crystal display device and the viewer. Reference numeral 8 denotes a liquid crystal display device and 9 denotes a viewer. A viewing distance 10 is a distance from the display surface of the liquid crystal display device 8 to the viewer 9. The viewing distance 10 is determined by using a distance measuring sensor that measures the setting and distance by the user, and the quality of the backlight is adjusted by selecting the backlight brightness, output volume, and image processing circuit to be used. Reduces power consumption while maintaining.

  For example, when the viewing distance is long, fine image processing is unnecessary, and the number of image processing circuits to be used can be reduced. When the viewing distance is short, the luminance of the backlight can be lowered from the reference value, and the output volume can be made smaller than the current set volume.

  FIG. 4 is an example of a flowchart for controlling the viewing distance. It is assumed that energy-saving control based on the viewing distance between the viewer and the liquid crystal display device is started (step S5). When the mode is switched to the energy saving mode and the viewing distance control mode is entered, the setting values of backlight luminance, output volume, and image processing circuit selection are determined based on the viewing distance value in step S6. Power consumption is reduced by controlling the backlight brightness, output volume, and selection of the image processing circuit to be used according to these set values.

  Next, FIG. 5 shows an example of setting values for each item of backlight luminance, output volume, and image processing circuit selection when the energy saving mode is changed stepwise. For example, in the energy saving mode 1, the backlight is not controlled, the output sound volume level is lowered by one, the edge correction circuit is stopped, and the power consumption is reduced by bypassing. In energy saving mode 2, the backlight is dimmed by one level and the output volume level is lowered by one. In the energy saving mode 3, the backlight is dimmed by one level, the output volume level is lowered by 1, the edge correction processing circuit is stopped and bypassed. In the energy saving mode 4, the backlight is dimmed in two steps, the output volume level is lowered by two, the edge correction and noise removal circuit is stopped and bypassed to reduce the power consumption of the liquid crystal display device.

  As described above, the power consumption is finely limited by switching the energy saving mode step by step by changing the combination of each item according to the command from the viewing condition (for example, viewing distance) and the control signal (luminance level control, etc.). Thus, it is possible to reduce power consumption during use. Of course, the combination of control items is not limited to FIG.

  As described above, the liquid crystal display device according to the embodiment of the present invention is characterized by the following configurations and operations. That is, a means for switching to the energy saving mode for reducing power consumption is provided, and by switching to the energy saving mode, power consumption can be reduced by backlight luminance control, image processing circuit selection control, and output volume control. Further, regarding the energy saving mode, the power consumption can be finely adjusted stepwise by switching and combining the backlight luminance, the selection of the image processing circuit to be used, and the output volume.

  In addition to energy saving mode switching, in addition to user operations (for example, the user operating the energy saving mode switching unit shown in FIG. 1), the viewing distance (see FIG. 1) between the liquid crystal display device and the user. Although not shown, a viewing distance control mode unit corresponding to the viewing distance measured by the distance measuring sensor is provided), the brightness of the backlight, the image quality, By adjusting the output volume, the power consumption can be reduced without degrading the viewing quality of the liquid crystal display device. At this time, it is shown in FIG. 5 that the mode 1, 2,... Is provided by the energy saving mode switching unit shown in FIG. 1 and any one mode is selected. 1 may be selected according to the viewing distance, and the energy saving mode is entered according to the viewing distance, and the setting value of the backlight control unit shown in FIG. 1 is determined. It may be configured. The viewing distance control mode unit may be provided alone to be in the energy saving mode, or may be configured to be added to the energy saving mode of the operation means by the user.

1 is a block diagram illustrating an overall configuration of a liquid crystal display device according to an embodiment of the present invention. It is a flowchart which shows the procedure which produces | generates the control signal for the power consumption reduction in the energy saving mode in the liquid crystal display device which concerns on this embodiment. It is a figure showing the viewing distance of the liquid crystal display device which concerns on this embodiment, and a viewer. It is a flowchart which shows the energy-saving setting item in the energy-saving mode by viewing distance shown in FIG. It is a figure which shows the setting value of each item of a backlight brightness | luminance, an output volume, and image processing circuit selection when changing the energy-saving mode in the liquid crystal display device which concerns on this embodiment in steps.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image signal processing part 2 Image processing selection control part 3 Energy saving mode switching part 4 Audio | voice output control processing part 5 Backlight control part 6 Display apparatus 7 Speaker 8 Liquid crystal display apparatus 9 Viewer 10 Viewing distance

Claims (7)

In a transmissive liquid crystal display device,
A liquid crystal display device comprising switching means for switching to a low power consumption mode, wherein brightness of a backlight is controlled by switching the switching means. In claim 1,
A liquid crystal display device characterized by controlling whether or not an image processing circuit is selected as an example of an edge correction processing circuit by switching the switching means. In claim 1 or 2,
A liquid crystal display device, wherein the output volume is controlled by switching the switching means. In a transmissive liquid crystal display device,
Having a switching means for switching to a low power consumption mode,
A liquid crystal display device characterized by controlling the brightness of a backlight and whether or not to use an image processing circuit as an example of an edge correction processing circuit by switching the switching means. In claim 4,
By switching the switching means, the brightness level of the power consumption mode is controlled by controlling the brightness level of the backlight, the selection of which of the plurality of image processing circuits to use, and the volume level of the output volume. Liquid crystal display device characterized by switching In a transmissive liquid crystal display device,
A distance measuring sensor for measuring the viewing distance of the liquid crystal display device and the user;
According to the measured viewing distance, the brightness of the backlight and the selection of use of an image processing circuit taking an edge correction processing circuit as an example, and the output volume are controlled. In claim 6,
Low power consumption by controlling the brightness level of the backlight, the selection of which of a plurality of image processing circuits to use, and the volume level of the output sound volume according to the measured viewing distance. A liquid crystal display device characterized by switching the strength of the mode step by step.

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