JP2011186237A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device for securing certain visibility with respect to OSD display, even when brightness of display video on a liquid crystal display panel is set dark. <P>SOLUTION: When the OSD display is performed, respective LEDs corresponding to OSD display areas r1, r2 where the OSD display is performed are lit on by preset OSD display luminance so as to secure fixed luminance; respective LEDs corresponding to another video area r3 are lit with light and darkness adjustment luminance corresponding to brightness of a video as a whole, displayed on the liquid crystal display panel according to a prescribed operation input. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device equipped with a backlight device that illuminates a liquid crystal display panel from behind by a large number of LEDs arranged in a matrix, and in particular, various OSD displays such as a menu screen, channel display, and volume display. It is related with the technique for ensuring visibility of.

Liquid crystal display devices such as liquid crystal television receivers and liquid crystal monitor devices are equipped with a backlight device that illuminates the liquid crystal display panel from behind. In the liquid crystal display device, the brightness of the display image on the liquid crystal display panel can be changed according to user's arbitrary setting. At this time, the brightness of the display image on the liquid crystal display panel is adjusted by changing the illumination amount of the liquid crystal display panel by the backlight device.
Conventionally, when the brightness of the display image on the liquid crystal display panel is set to be extremely dark, the OSD display such as the menu screen is darkened and the visibility is lowered, resulting in a problem that the operability is lowered.
Therefore, for example, Patent Document 1 proposes changing the color of the OSD display so that the OSD display is easy to see even when the brightness of the display image on the liquid crystal display panel is changed.

JP 2008-116555 A

However, if the light intensity of the backlight device becomes too low to reduce the brightness of the display image on the liquid crystal display panel, there is a problem that the visibility of the OSD display is not improved even if the color of the OSD display is changed.
On the other hand, in recent years, LEDs arranged in a matrix are sometimes used as a light source of a backlight device in place of a cold cathode tube. In such a configuration, each of the LEDs can be individually turned on / off, and the brightness of the liquid crystal display panel can be partially changed.
Therefore, the present invention has been made in view of the above circumstances, and the object of the present invention is to ensure a certain visibility for OSD display even when the brightness of the display image of the liquid crystal display panel is set to be dark. An object of the present invention is to provide a liquid crystal display device that can be used.

In order to achieve the above object, the present invention provides a liquid crystal display panel for displaying an image, a backlight device having a plurality of LEDs arranged in a matrix on the back side of the liquid crystal display panel, and the liquid crystal display panel. OSD display means for OSD displaying characters and / or images in a preset OSD display area; and image brightness setting means for setting the brightness of the entire image displayed on the liquid crystal display panel according to a predetermined operation input. , Applied to a liquid crystal display device comprising: LED control means for lighting each LED with a brightness adjustment brightness corresponding to the brightness of the entire video set by the video brightness setting means, When the OSD display is performed by the OSD display unit, the LED control unit corresponds to the OSD display area in which the OSD display is performed. ED is lit at a preset OSD display luminance, configured as a liquid crystal display device, characterized in that the LED corresponding to other regions is intended to be turned by the dark-adjusted luminance.
According to the present invention, even when the brightness of the display image of the liquid crystal display panel is set to be dark by the image brightness / darkness setting means, the OSD display is performed with the brightness set separately from the brightness of the display image. Therefore, it is possible to ensure a certain visibility for the OSD display.

Here, it is preferable that the LED control means switches according to a predetermined operation input whether the LED corresponding to the OSD display area is lit at the OSD display brightness or the brightness adjustment brightness. Accordingly, since the user can arbitrarily select whether the LED corresponding to the OSD display area is lit at the OSD display brightness or the brightness adjustment brightness, the OSD display also has the same brightness as the display image. Now, it is possible to respond to the user's desire to display it.
By the way, it is conceivable that the OSD display luminance is a predetermined constant value. As a result, the brightness of the OSD display can always be kept constant, so that a certain level of visibility can be secured for the OSD display.
Further, the LED control means sets the OSD display luminance with a predetermined value set as a lower limit value in accordance with a decrease in brightness of the entire video set by the video brightness setting means. Is also possible. Thereby, since only the OSD display luminance is not set to be less than the lower limit value, it is possible to ensure a certain visibility for the OSD display.
Furthermore, the OSD display brightness is adjusted so that the LED control means reduces the brightness at a gentler slope than the brightness adjustment brightness as the overall brightness of the video set by the video brightness setting means decreases. It can also be set. Thereby, even when the brightness adjustment brightness is changed to be extremely dark, the OSD display brightness is set with a gentler slope than that, so that the OSD display can be prevented from becoming too dark. .

  According to the present invention, even when the brightness of the display image of the liquid crystal display panel is set to be dark by the image brightness / darkness setting means, the OSD display is performed with the brightness set separately from the brightness of the display image. Therefore, it is possible to ensure a certain visibility for the OSD display.

1 is a block diagram illustrating a schematic configuration of a liquid crystal television receiver X which is an example of a liquid crystal display device according to the present invention. FIG. 5 is a schematic diagram showing an example of setting an OSD display area in the liquid crystal television receiver X. 6 is a flowchart showing an example of a procedure of OSD display control processing in the liquid crystal television receiver X. The figure for demonstrating an example of the execution result of the OSD display control process in the liquid crystal television receiver. The figure for demonstrating the other example of the execution result of the OSD display control process in the liquid crystal television receiver X. FIG. The figure for demonstrating an example of the setting method of OSD display brightness | luminance.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings so that the present invention can be understood. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.
First, the configuration of a liquid crystal television receiver X, which is an example of a liquid crystal display device according to the present invention, will be described with reference to FIG. The present invention can be applied not only to a liquid crystal television receiver but also to a liquid crystal display device such as a liquid crystal display device used in a personal computer.
As shown in FIG. 1, a liquid crystal television receiver X includes a plurality of tuners 1, an external signal input unit 2, a demodulation / separation circuit 3, a video decoding circuit 11, a video selection / synthesis circuit 12, a video processing circuit 13, a liquid crystal Driver 14, liquid crystal display panel 15 (an example of video display means), dimming circuit 16, backlight device 17, audio decoding circuit 21, audio selection circuit 22, audio processing circuit 23, amplifier 24, speaker 25, control circuit 4 A remote control light receiving unit 6 and a remote control 7 are provided.
The liquid crystal television receiver X according to the present embodiment performs the OSD display on the liquid crystal display panel 15 by performing the OSD display control process (see FIG. 3) described later by the control circuit 4. The OSD display area where the OSD display is performed is characterized in that a certain brightness is ensured.

The remote control light receiving unit 6 is a signal transmission interface that receives a radio signal by infrared rays from a remote control 7 (remote controller) for operating the liquid crystal television receiver X according to a predetermined signal transmission protocol (so-called remote control protocol). is there. The remote control light receiving unit 6 extracts a signal representing operation input information for the remote control 7 from the infrared signal, and transmits the signal to the control circuit 4.
The control circuit 4 includes an MPU 4a that is an arithmetic means, and a ROM 4b (EPROM) and an EEPROM 4c that are storage means, and the MPU 4a controls the entire liquid crystal television receiver X by executing a control program. The ROM 4b stores in advance a control program executed by the MPU 4a. The EEPROM 4c stores various data that is read and written (referenced or written) in the process executed by the MPU 4a.
For example, the control circuit 4 acquires channel tuning and volume control information through the remote controller 7 and the remote control light receiving unit 6, and selects a tuning instruction for the tuner 1 and the amplifier 24 according to the contents of the acquired information. Outputs volume adjustment instructions.

The tuner 1 is an electronic component that extracts a signal of content (broadcast program) being broadcast from a television broadcast signal received by an antenna (not shown). More specifically, the tuner 1 extracts a carrier frequency component signal including a broadcast program signal instructed to be selected by the control circuit 4, and transmits the extracted signal to the demodulation / separation circuit 3 in the subsequent stage. To do. The tuner 1 is provided for each broadcasting medium (terrestrial wave, BS, CS, etc.).
The external signal input unit 2 receives video and audio signals from an external device such as a DVD player, a Blu-ray disc player, a Web streaming receiving device (such as an Internet modem), and the video selection / synthesis circuit 12 and the video signal. This is a signal input interface to be input to the voice selection circuit 22. The external signal input unit 2 extracts metadata that is input while being superimposed on the video signal, and inputs the extracted metadata to the control circuit 4.
The demodulation / separation circuit 3 demodulates a transport stream signal (Transport Stream signal: hereinafter referred to as a TS signal) from the carrier frequency component transmitted from the tuner 1. Further, the demodulation / separation circuit 3 separates and extracts a video signal and an audio signal corresponding to a broadcast program to be viewed and metadata (content information) from the extracted TS signal. Further, the demodulation / separation circuit 3 extracts a video signal and an audio signal of a broadcast program to be viewed according to a PID (Packet IDentification) received from the control circuit 4, and each signal is extracted from the video decoding circuit 11 And to each of the speech decoding circuits 21.

The audio decoding circuit 21 decodes the audio signal transmitted from the demodulation / separation circuit 3 and transmits the decoded audio signal to the audio selection circuit 22.
In addition, the audio selection circuit 22 is responsive to a control command from the control circuit 4 to transmit a broadcast program content audio signal selected by the tuner 1 (an audio signal input through the audio decoding circuit 21), In this circuit, one audio signal is selected from the audio signals input through the external signal input unit 2 and transmitted to the audio processing circuit 23.
The voice processing circuit 23 performs various signal processing on the voice signal selected by the voice selection circuit 22 in accordance with an instruction from the control circuit 4. For example, equalization processing, surround processing, or the like according to the characteristics of the speaker 25 is performed.
The amplifier 24 amplifies or attenuates the audio signal processed by the audio processing circuit 23 in accordance with an instruction from the control circuit 4 and outputs the amplified signal to the speaker 25.

On the other hand, the video decoding circuit 11 decodes the video signal transmitted from the demodulation / separation circuit 3 and transmits the decoded video signal to the video selection / synthesis circuit 12.
The video selection / synthesizing circuit 12 is responsive to a control command from the control circuit 4 to output a video signal of broadcast program content input through the video decoding circuit 11 and external input content input through the external signal input unit 2. One or a plurality of video signals are selected from the video signals and transmitted to the video processing circuit 13.
The video processing circuit 13 generates a frame image signal to be supplied to the liquid crystal driver 14 in order to display a content image on the liquid crystal display panel 15 in accordance with a control command from the control circuit 4. Specifically, the control circuit 4 displays an OSD display necessary according to the operation contents when an operation input such as a menu screen display, channel switching, or volume change is performed by a user operation of the remote controller 7. A control command is given to the video processing circuit 13 so as to execute. As a result, the video processing circuit 13 causes the OSD to display characters and images such as menu screens, channel displays, and volume displays superimposed on the display video of the liquid crystal display panel 15 in accordance with the control command from the control circuit 4. Execute the display. Here, the control circuit 4 and the video processing circuit 13 when performing the OSD display correspond to the OSD display means. Of course, the OSD display is a concept including not only the above-described examples but also subtitles, telops, and the like as long as the OSD display is displayed superimposed on the display image of the liquid crystal display panel 15.

The liquid crystal driver 14 controls the liquid crystal display panel 15 based on the frame image signal sequentially transmitted from the video processing circuit 13 in a predetermined cycle, and corresponds to one frame (one frame) corresponding to the frame image signal. Are sequentially displayed on the liquid crystal display panel 15.
The liquid crystal display panel 15 changes the transmittance for each liquid crystal element arranged in a matrix in accordance with control by the liquid crystal driver 14 and displays an image corresponding to the frame image signal.
The backlight device 17 has a number of LEDs arranged in a matrix on the back side of the liquid crystal display panel 15 and illuminates the liquid crystal display panel 15 from the back side.
The dimming circuit 16 controls the light emission luminance of each LED by adjusting the power supplied to each of the LEDs provided in the backlight device 17 in accordance with a control command from the control circuit 4, so that the liquid crystal The brightness of the display image on the display panel 15 is adjusted. The brightness of the display image on the liquid crystal display panel 15 is the reference brightness when displaying the image on the liquid crystal display panel 15, and the light emission luminance of each LED of the backlight device 17 is the reference brightness. It is also conceivable that the luminance is increased or decreased according to the content of the display image on the basis of the light emission luminance corresponding to the brightness.

FIG. 2 is a schematic view of the liquid crystal display panel 15 and the backlight device 17.
As shown in FIG. 2, when the menu screen is displayed on the liquid crystal display panel 15 by OSD, the video display area of the liquid crystal display panel 15 includes OSD display areas r1 and r2 where the OSD display is performed, and the OSD display area. It is divided into a video area r3 excluding r1 and r2. The OSD display area r1 is a main menu display area of the menu screen, and the OSD display area r2 is a submenu display area of the menu screen (see, for example, FIG. 4). Information for specifying the OSD display areas r1 and r2 and the video area r3 is stored in the ROM 4b of the control circuit 4, and the control circuit 4 transmits the OSD display areas r1 and r2 and the video image. The region r3 can be distinguished.
On the other hand, the backlight device 17 has a plurality of white LEDs 17 a arranged on the back side of the liquid crystal display panel 15 vertically and horizontally by a predetermined number according to the size of the liquid crystal display panel 15. . Here, each LED 17a corresponds to each unit area on the liquid crystal display panel 15, and the correspondence between each LED 17a and the unit area mainly illuminated by the LED 17a is known. Of course, the LED 17a may include LEDs of three colors of RGB.
Here, the LEDs 17a corresponding to the OSD display areas r1 and r2 are preset as LED groups 171 and 172, and the ED 17a corresponding to the video area r3 as an LED group 173 and stored in the ROM 4b of the control circuit 4 or the like. It shall be. Thereby, the control circuit 4 can distinguish the LED groups 171 to 173.
The dimming circuit 16 divides the emission luminance of each of the LEDs 17a in the backlight device 17 into the LED groups 171 and 172 and the LED groups 173 individually in accordance with a control command from the control circuit 4. Control.

Here, in the liquid crystal television receiver X, the light emission luminance of each of the LEDs 17a preset in the ROM 4b of the control circuit 4 corresponding to the standard brightness of the display image of the liquid crystal display panel 15 is set. It is assumed that the standard luminance K0 is stored. Thereby, in the initial state, the control circuit 4 transmits the standard luminance K0 to the dimming circuit 16, so that the brightness of the display image on the liquid crystal display panel 15 is standardized by the dimming circuit 16. Adjusted to.
On the other hand, the control circuit 4 has a video brightness setting function for arbitrarily setting the brightness of the entire video displayed on the liquid crystal display panel 15 in accordance with an operation input (predetermined operation input) of the remote controller 7 by the user. Have. Here, the control circuit 4 when performing such setting corresponds to the image contrast setting means. Hereinafter, the light emission brightness of each of the LEDs 17a corresponding to the brightness of the entire video set by the video brightness setting function is referred to as brightness adjustment brightness K1. The relationship between the brightness of the entire image and the brightness adjustment brightness K1 is stored in advance in the ROM 4b of the control circuit 4 or the like.
When the brightness of the display image on the liquid crystal display panel 15 is changed by the image brightness setting function, the control circuit 4 thereafter turns on each of the LEDs 17a with the brightness adjustment brightness K1 corresponding to the brightness. A control command is given to the light control circuit 16. Accordingly, the light control circuit 16 adjusts the brightness of the display image on the liquid crystal display panel 15 by adjusting the light emission brightness of each of the LEDs 17a based on the brightness adjustment brightness K1. Here, the control circuit 4 and the dimming circuit 16 when executing such processing correspond to LED control means.

By the way, if the brightness of the display image set by the image contrast setting function is too dark, the brightness of the OSD display such as the menu screen is also too dark, and the visibility may be lowered. In particular, since the brightness setting by the image brightness / darkness setting function is performed by an operation input in accordance with an OSD-displayed menu screen, when the OSD display is set to be extremely dark, the brightness of the display image is subsequently adjusted. It becomes difficult to perform an operation input for returning.
However, in the liquid crystal television receiver X, even if the brightness of the display image is set to be dark by the image brightness setting function by executing the OSD display control process by the control circuit 4, A certain level of brightness is secured for the OSD display areas r1 and r2.
Hereinafter, an example of the procedure of the OSD display control process executed by the control circuit 4 will be described with reference to the flowchart of FIG. Note that S1, S2,... Shown below represent identification codes of processing procedures (steps).

(Step S1)
First, in step S1, the control circuit 4 determines whether it is necessary to perform OSD display by an operation input of the remote controller 7 or the like by the user. Specifically, the control circuit 4 determines that it is necessary to perform OSD display when operations such as menu screen display, channel tuning, and volume adjustment are performed on the remote controller 7.
If it is determined that the OSD display needs to be performed (Yes side of S1), the process proceeds to step S2, and if the OSD display does not need to be performed (No side of S1). , The process proceeds to step S11.

(Step S11)
In step S11, the control circuit 4 displays the display image of the entire area including the OSD display areas r1, r2 and the video area r3 on the liquid crystal display panel 15 with the same brightness.
Specifically, when the brightness of the display image is not changed by the image contrast setting function, each of the LEDs 17a corresponding to all the regions including the OSD display regions r1, r2 and the image region r3 has the standard luminance K0. Emits light. Further, when the brightness of the display image is changed by the image contrast setting function, each of the LEDs 17a corresponding to the entire region including the OSD display regions r1, r2 and the image region r3 is adjusted to the brightness adjustment brightness K1. It emits light.

(Step S2)
On the other hand, in step S2, the control circuit 4 determines whether or not the brightness of the display image on the liquid crystal display panel 15 is set to be less than a predetermined brightness by the image brightness / darkness setting function. Here, the predetermined brightness is set in advance so as to ensure a certain visibility for the OSD display when the OSD display is performed. Note that the brightness of the image when at least each of the LEDs 17a is lit at the standard brightness K0 is equal to or higher than the predetermined brightness.
Here, when it is determined that the brightness is less than the predetermined brightness (Yes side of S2), the process proceeds to Step S3, but when the brightness is equal to or higher than the predetermined brightness (No side of S2). ) Even if the OSD display is performed as it is, a certain degree of visibility is ensured for the OSD display. Therefore, the process proceeds to step S11, and the entire area is displayed with the same brightness.

(Steps S3 to S4)
When the brightness of the display image on the liquid crystal display panel 15 is less than the predetermined brightness (Yes side of S2), if the OSD display is performed with the same brightness as it is, the visibility of the OSD display is difficult to be seen. There is a problem.
Therefore, in the liquid crystal television receiver X, in the subsequent steps S3 to S4, the control circuit 4 presets each of the LEDs 17a belonging to the LED groups 171 and 172 corresponding only to the OSD display amount regions r1 and r2. A control command is sent to the dimming circuit 16 so that the LED 17a is lit at the standard brightness K0, which is a constant value, and the LEDs 17a belonging to the LED group 173 corresponding to the video area r3 are lit at the brightness adjustment brightness K1. give. Thereby, the light amount of the backlight device 17 is adjusted by the dimming circuit 16, the LED 17a corresponding to the OSD display areas r1 and r2 is lit at the standard luminance K0, and the LED 17a corresponding to the video area r3. Lights up with the brightness adjustment brightness K1.

As described above, in the liquid crystal television receiver X, the OSD display areas r1 and r2 have a constant brightness even when the brightness of the display image is set to be extremely dark by the image brightness setting function. Therefore, a certain visibility can be secured for the OSD display.
It is desirable that the OSD display control process can be switched between valid / invalid. Specifically, whether the control circuit 4 turns on the LED 17a corresponding to the OSD display areas r1 and r2 at the standard brightness K0 or the brightness adjustment brightness K1 in response to a user operation on the remote controller 7. Can be considered. Accordingly, the user can select whether or not to execute the OSD display control process, that is, whether or not to ensure a certain brightness for the OSD display, according to his / her preference.

FIG. 4 shows an example of the execution result of the OSD display control process. When the brightness of the display image is set to be less than the predetermined brightness by the image brightness / darkness setting function, FIG. The example of a display in case OSD display of a menu screen is performed in OSD display area r1, r2.
As shown in FIG. 4, with respect to the video area r3, each of the LEDs 17a is lit with the brightness / darkness adjustment brightness K1 set by the video brightness / darkness setting function. The image becomes darker than the brightness.
However, in the OSD display areas r1 and r2, each of the 17a lights up at the standard luminance K0, so that the OSD display in the OSD display areas r1 and r2 is brighter than the predetermined brightness. A certain level of visibility is ensured.

In this embodiment, the case where the menu screen is OSD-displayed is described as an example. However, the present invention is not limited to this, and the same applies to the case where OSD display such as channel display or volume display is performed.
That is, in addition to the OSD display areas r1 and r2, partial areas for performing channel display and volume display are set in advance as individual OSD display areas. When the control circuit 4 performs OSD display, What is necessary is just to control so that fixed brightness is ensured only about the OSD display area corresponding to the content of OSD display.
For example, FIG. 5 shows a result when OSD display of channel display is performed in the OSD display region r11 at the upper right end portion of the liquid crystal display panel 15 instead of the menu screen. As shown in FIG. 5, the LED 17a corresponding to only the OSD display area r11 where the OSD display of the channel display is performed lights up at the standard luminance K0, thereby ensuring a certain visibility.

By the way, in the said embodiment, the case where the brightness | luminance of said LED17a corresponding to the said OSD display area r1, r2 was made into the said standard brightness | luminance K0 of a fixed value was mentioned as an example, and was demonstrated.
On the other hand, it is conceivable that the control circuit 4 changes the luminance of the LED 17a in the OSD display areas r1 and r2 in accordance with the change in the brightness of the display image on the liquid crystal display panel 15. However, it is necessary to ensure a certain visibility for the OSD display areas r1 and r2.

  Therefore, as shown in FIG. 6A, the control circuit 4 causes the brightness adjustment brightness K1 to decrease as the brightness of the entire image set by the image brightness setting function decreases. The OSD display brightness K2 that is the light emission brightness of the LED 17a corresponding to the OSD display areas r1 and r2 is gradually set low. The lower limit value of the OSD display brightness K2 is set to ensure a certain visibility for the OSD display. It is conceivable to set the OSD display luminance K2 as a predetermined value Km set in advance. As a result, the LED 17a corresponding to the OSD display areas r1 and r2 emits light at least at the OSD display luminance K2 or more, and therefore a certain brightness can be secured for the OSD display areas r1 and r2.

  Further, as shown in FIG. 6B, the control circuit 4 causes the brightness adjustment brightness K1 to decrease as the brightness of the entire image set by the image brightness setting function decreases. It is conceivable to set the OSD display brightness K2 of the LED 17a corresponding to the OSD display areas r1 and r2 to be gradually lower with a gentler slope than the brightness adjustment brightness K1. As a result, even when the brightness adjustment brightness K1 is changed to be extremely dark, the OSD display brightness K2 is set to be dark with a gentler slope, thereby preventing the OSD display from becoming too dark. be able to. Even in this case, the OSD display brightness K2 is set with the predetermined value Km set in advance as a lower limit value so as to ensure a certain visibility for the OSD display.

X: Liquid crystal television receiver (an example of a liquid crystal display device)
1: Tuner 2: External signal input unit 3: Demodulation / separation circuit 4: Control circuit 6: Remote control light receiving unit 7: Remote control 11: Video decoding circuit 12: Video selection / synthesis circuit 13: Video processing circuit 14: Liquid crystal driver 15: Liquid crystal display panel 16: Dimming circuit 17: Backlight devices 171-173 ... LED group 17a: LED
21: Audio decoding circuit 22: Audio selection circuit 23: Audio processing circuit 24: Amplifier 25: Speakers r1, r2 ... OSD display area r3 ... Video area S1, S2, ...: Processing procedure (step) number

Claims (5)

A liquid crystal display panel for displaying an image, a backlight device having a plurality of LEDs arranged in a matrix on the back side of the liquid crystal display panel, and characters and / or characters in a preset OSD display area on the liquid crystal display panel Alternatively, the OSD display means for OSD-displaying the image, the video light / dark setting means for setting the brightness of the entire video displayed on the liquid crystal display panel in response to a predetermined operation input, and the video light / dark setting means A liquid crystal display device comprising LED control means for turning on each of the LEDs with a brightness adjustment brightness corresponding to the brightness of the entire image,
When the OSD display is performed by the OSD display unit, the LED control unit turns on the LED corresponding to the OSD display area in which the OSD display is performed with a preset OSD display luminance, so that another area is displayed. A liquid crystal display device characterized in that the LED corresponding to 1 is turned on at the brightness adjustment brightness.   2. The liquid crystal according to claim 1, wherein the LED control means switches whether the LED corresponding to the OSD display area is lit at the OSD display brightness or the brightness adjustment brightness according to a predetermined operation input. Display device.   The liquid crystal display device according to claim 1, wherein the OSD display luminance is a predetermined constant value.   2. The LED control means sets the OSD display luminance with a predetermined value set as a lower limit as the overall brightness of the video set by the video brightness setting means decreases. Or a liquid crystal display device according to any one of 2;   The LED control means sets the OSD display brightness so that the brightness decreases at a gentler slope than the brightness adjustment brightness as the overall brightness of the video set by the video brightness setting means decreases. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is a liquid crystal display device.