JP5901185B2 - Backlight device and control method thereof - Google Patents

Description

  The present invention relates to a backlight device and a control method thereof.

  In recent years, those using liquid crystals have become mainstream as image display devices. Since the liquid crystal panel is not a self-luminous device, a light source for irradiating the liquid crystal from the back surface is necessary to display an image. In recent years, an LED (light-emitting diode) is increasing as the light source. By using the LED as the light source, it is possible to reduce power consumption and to finely control the light emission of the light source, thereby providing various advantages. Next, some basic control methods related to the backlight will be described.

  Luminance adjustment: In a liquid crystal display device, there are two methods for adjusting the display luminance: a method of adjusting the light transmittance of the backlight using liquid crystal, and a method of changing the luminance of the backlight. In order to increase the contrast ratio in the screen, it is better to use a method of adjusting the luminance with a backlight. PWM (pulse width modulation) is a method often used as a method for adjusting the luminance of the backlight. This method is a method of adjusting the luminance of the backlight by turning on and off the backlight at a constant cycle (flashing at a constant cycle) and changing the ratio (duty ratio) between the lighting period and the off period. As a method for adjusting the brightness of the main backlight other than the PWM, there is a method for increasing or decreasing the value of the current flowing through the LED.

  Unevenness correction: There are individual differences in LEDs, and even when the same amount of current is supplied and PWM control is performed with the same duty ratio, there may be differences in luminance. In addition, the brightness varies depending on temperature conditions and aging. When used as a backlight with a difference in brightness, the display brightness and display chromaticity appear uneven. Therefore, the display brightness and display chromaticity in the screen are made uniform by changing the current value and PWM duty ratio for each LED control unit in consideration of various conditions such as individual differences of LEDs, temperature, and aging. The technology for achieving this is unevenness correction.

  Local dimming: When displaying black in a liquid crystal display device, black is expressed by blocking the light of the backlight by closing the liquid crystal shutter. However, the light shielding by the liquid crystal is not sufficient, and in fact, even if the liquid crystal shutter is closed, a slight leak of light occurs, and so-called “black floating” occurs where sufficient black cannot be expressed. The contrast ratio in the screen is limited by the black float. A technique for solving this problem is a technique called local dimming. This is a technology that makes it possible to increase the contrast ratio in the screen by suppressing black float by controlling the brightness of the backlight for each area in the screen according to the brightness of the input image. It is disclosed in Patent Document 1 and the like.

  Backlight scan: The liquid crystal panel is inferior in responsiveness compared to a self-luminous display such as a cathode ray tube display or a plasma display. Therefore, various techniques for solving this problem have been proposed today, and one of them is a technique called backlight scanning. This technique of backlight scanning is a technique for reducing moving image blur by turning off the backlight in accordance with the scanning (scanning) of the liquid crystal so as to make the moment of switching of the liquid crystal invisible. When this control is performed, the blinking frequency of the backlight needs to be the same as the scan frequency (frame frequency) of the liquid crystal, and the timing of turning on and off the PWM varies for each region in the screen. This technique is disclosed in Patent Document 2 and the like.

JP 2001-142409 A JP-A-11-202286

  By the way, many LEDs are arrange | positioned at the backlight using LED, It is necessary to control all of them. For LED control, an LED driver having a PWM control function and a current adjustment function is used. One LED driver generally has a plurality of control channels, and LED drivers that can change the duty ratio of PWM for each channel are mainstream. In addition, although the LED driver has a plurality of control channels, the number of LEDs used for the backlight is large. Therefore, when one LED is connected to each channel for control, a large number of LED drivers are used. Is required. When the number of LED drivers increases, problems such as an increase in cost, an increase in substrate area, and an increase in heat generation occur.

  Therefore, there is a method of reducing the number of LED drivers by connecting a plurality of LEDs to one channel of the LED driver. Even when the same voltage is applied to the LEDs, the flowing current varies due to individual differences, so it is not desirable to connect the LEDs in parallel to one channel. Therefore, when a plurality of LEDs are connected to one channel, the LEDs are generally connected in series as shown in FIG. In this way, it is possible to reduce the number of LED drivers by performing control using a plurality of directly connected LEDs as a control unit.

  In FIG. 7, the LEDs 711, 712, 713, and 714 connected in series to the first channel 710 of the LED driver 700 are all turned on and off at the same time, and the amount of current flowing is the same. For this reason, it is not possible to control each LED connected in series to the first channel 710 by individually changing the PWM duty ratio and current amount. The same applies to a plurality of LEDs connected in series to other channels. Therefore, it is necessary to determine the physical arrangement of the LEDs in consideration of the fact that the LEDs connected in series are subjected to the same lighting control.

  As shown in FIG. 7, two types of FIG. 8A and FIG. 8B are considered as physical LED arrangement examples when four LEDs are connected in series to one channel of the LED driver. However, in FIG. 8, only two channels of the first channel 710 and the second channel 720 are shown in order to avoid complicated drawing.

  When four LEDs are arranged in a square (rectangular shape) as shown in FIG. 8A, the light emission of the backlight can be controlled for each square LED block, so that LED control for local dimming and unevenness correction can be performed. It becomes easy. On the other hand, in this arrangement, the LEDs 711 and 713 are turned on simultaneously with the LEDs 712 and 714, and the LEDs 721 and 723 are turned on simultaneously with the LEDs 722 and 724. For this reason, when the backlight scan is performed, the switching timing of turning on and off the LEDs in the upper lines of LEDs 712, 714, 722, and 724 and the lower lines of LEDs 711, 713, 721, and 723 becomes simultaneous. That is, the backlight scan is controlled every two lines.

In the backlight scan, if the PWM duty ratio (the LED extinguishing period) is the same, the time from the liquid crystal scan (beginning of liquid crystal switching) until the backlight that illuminates the liquid crystal is turned on is longer. It is preferable to ensure it. In this way, the effect of improving the motion blur can be increased by adjusting the timing of turning off and turning on the backlight. Therefore, if the backlight scan advances every 2 LED lines, depending on the position on the liquid crystal panel, it is not possible to secure a sufficient time from the liquid crystal scan to the start of LED lighting, so the effect of improving motion blur is sufficient. I can not get to. The principle of improving the motion blur is detailed in Patent Document 2 and the like.

  Therefore, it is considered that a plurality of LEDs connected to the same channel are arranged in a horizontal row as shown in FIG. With this arrangement, the lighting start times of the LEDs 721, 722, 723, and 724 and the lighting start times of the LEDs 711, 712, 713, and 714 can be changed to different timings. Therefore, the LED lighting start time can be changed for each line in the backlight scan. Therefore, it is possible to extend the time from the start of switching of the liquid crystal to the time when the backlight is turned on, and it is possible to further increase the effect of improving the motion blur. On the other hand, when such an arrangement is used, it is difficult to perform LED control for each square LED block, so it can be said that the arrangement is not suitable for LED control for local dimming or unevenness correction.

  In the above description, it has been described that a plurality of LEDs connected to the same channel of the LED driver are generally suitable for local dimming as shown in FIG. This is not true in all cases. Depending on the displayed image, more effective local dimming can be achieved if a plurality of LEDs connected to the same channel of the LED driver are arranged in a line (rectangular) shape as shown in FIG. 8B, for example. There are cases where this can be done.

  In other words, conventionally, the physical arrangement of a plurality of LEDs connected to the same channel of the LED driver has been fixed, so that the effects of backlight control such as local dimming, display unevenness correction, and backlight scanning can be sufficiently obtained. There were cases where it was not possible.

  The present invention provides a backlight device and a control method therefor capable of more effectively performing backlight control such as local dimming, display unevenness correction, and backlight scan while suppressing an increase in the number of LED drivers to be used. For the purpose.

The present invention includes a plurality of light sources,
A plurality of driving means for driving the light source,
With
A plurality of light sources are connected to each driving means, and each driving means drives a plurality of connected light sources with the same drive signal, thereby forming a light source composed of a plurality of light sources connected to the same driving means. A backlight device in which light emission is controlled in units of blocks,
A plurality of switches for switching the connection between the driving means and the light source, the connection between the plurality of light sources connected to the driving means, and the connection between the light source and the power source that supplies power to the light source;
Control for changing the shape of a light source block composed of light sources connected to each driving means by changing each of the switches to change a driving means to which at least some of the light sources are connected. Means,
Equipped with a,
The control means, the shape of the light source block, a square shape to a rectangular shape, or a backlight device Ru changing to a square shape from a rectangle shape.

The present invention includes a plurality of light sources,
A plurality of driving means for driving the light source,
With
A plurality of light sources are connected to each driving means,
A method for controlling a backlight device comprising a plurality of switches for switching between a drive means and a light source, a connection between a plurality of light sources connected to the drive means, and a connection between a light source and a power source that supplies power to the light source. And
By switching each of the switches, the driving means to which at least some of the plurality of light sources are connected is changed, and the shape of the light source block constituted by the light sources connected to the driving means is changed to a square shape. Changing from a rectangular shape to a rectangular shape or from a rectangular shape to a square shape;
After changing the shape of the light source block, each driving unit drives a plurality of light sources to be connected with the same driving signal, whereby a light source block unit composed of a plurality of light sources connected to the same driving unit and controlling the light emission in,
A control method for a backlight device having a.

  According to the present invention, it is possible to more effectively perform backlight control such as local dimming, display unevenness correction, and backlight scan while suppressing an increase in the number of LED drivers to be used.

1 is a block diagram illustrating a schematic configuration of an image display apparatus according to a first embodiment. The figure which shows the structure of LED and a switch of Example 1. The figure which shows how to change the switch of Example 1, and the LED block at that time The figure which shows how to change the switch of Example 1, and the LED block at that time The figure which shows the display image of Example 2, and the LED block of a backlight The figure which shows the LED block and lighting example of the backlight of Example 2. The figure which shows the example of a connection of LED driver and LED in a prior art The figure which shows the example of arrangement | positioning of LED in a prior art

(Example 1)
A first embodiment of the present invention will be described. FIG. 1 is a block diagram illustrating a schematic configuration of the image display apparatus according to the first embodiment. In the image display device 100, the LCD control unit 102 controls the LCD panel 103, which is a liquid crystal panel, based on the image data input from the image input unit 101 to align the liquid crystal, so that an image based on the image data is displayed on the LCD. It is displayed on the panel 103. The image analysis unit 104 analyzes the input image data, and the backlight control unit 105 determines a control method of the backlight 110 based on the analysis result. The backlight control unit 105 sets information necessary for controlling the backlight 110 such as a duty ratio and a current amount in the LED drivers 106, 107, 108, and 109. LED drivers 106, 107, 108, and 109 drive LEDs that are light sources of the backlight 110 based on information received from the backlight control unit 105. That is, the LED drivers 106, 107, 108, and 109 blink LEDs (light-emitting elements) with a drive signal having a constant frequency with a set duty ratio and current amount based on information received from the backlight control unit 105. Let In addition, the backlight control unit 105 switches a switch included in the backlight 110 as necessary. Details of the LEDs and switches of the backlight 110 are shown in FIG. The image analysis unit 104, the backlight control unit 105, the LED drivers 106 to 109, and the backlight 110 constitute a backlight device (backlight module). However, the backlight device may be configured not to include the image analysis unit 104. The backlight device may include the image input unit 101.

FIG. 2A is a diagram showing a part of the LEDs and switches constituting the backlight 110. In the LED driver 106, LEDs 203 to 210 are connected to the first control channel 201 and the second control channel 202 via switches 211 to 214. Each LED is lit by the voltage supplied from the voltage supply terminals 215 to 217. Actually, the LED driver 106 has a larger number of control channels, and more LEDs can be connected. However, in FIG. 2A, the illustration is omitted to avoid complication of the drawing. The switches 211 to 214 are a connection between the LED driver control channel and the LED, a connection between LEDs that are a plurality of light sources connected to the LED driver control channel, and a power source that supplies power to the LED and the LED. The connection with a certain voltage supply terminal is interrupted. Hereinafter, only the two channels of the first control channel 201 and the second control channel 202 will be described.

  FIG. 2B shows the LED arrangement of the entire backlight 110 including the LEDs 203 to 210. In an actual image display apparatus, the number of LEDs constituting the backlight 110 may be further increased depending on the screen size or the like. However, in this embodiment, for simplicity, the backlight 110 has a total of 96 horizontal 12 × vertical 8 pixels. The description will be made on the assumption that the LED is composed of individual LEDs. In addition, the image display apparatus according to the first embodiment can switch between two backlight control modes. That is, there are a “local dimming mode” that prioritizes local dimming control and unevenness correction control, and a “backlight scan mode” that prioritizes control for reducing moving image blur by backlight scan control.

When performing the local dimming control, the backlight control unit 105 outputs a drive signal output from the LED driver control channel so that the luminance of each LED block becomes the luminance according to the image data of the area corresponding to each LED block. Control.
When performing the unevenness correction control, the backlight control unit 105 controls the drive signal output from the LED driver control channel so that the brightness of each LED block becomes the brightness according to the light emission characteristics of the LED of each LED block. .
When performing backlight scan control, the backlight control unit 105 outputs from the LED driver control channel so that each LED block can be switched on and off in accordance with the scan of the liquid crystal panel illuminated by the backlight. Control the signal.

  The selection of the backlight control mode may be a configuration that can be specified by the user via a user interface (not shown), or a configuration that switches to a control mode that the backlight control unit 105 determines to be optimal according to input image data. It may be. For example, the local dimming mode is set for still image data, and the backlight scan mode is set for moving image data. The backlight control unit 105 controls the operation of each switch.

  When “local dimming mode” is selected, the backlight control unit 105 switches each switch to a predetermined position as shown in FIG. That is, the backlight control unit 105 switches each switch so that the switch 211 is connected to the right terminal A and the switches 212, 213, and 214 are connected to the left terminal B. When the switches are switched in this way, the LEDs 208, 207, 204, and 203 are connected in series to the first control channel 201 of the LED driver 106, and these four LEDs supply voltage from the voltage supply terminal 215. Is done. The LEDs 210, 209, 206, and 205 are connected in series to the second control channel 202 of the LED driver 106, and these four LEDs are supplied with a voltage from a voltage supply terminal 217.

At this time, as shown in FIG. 3B, the LED block 301 is composed of the four LEDs 203, 204, 207, and 208 in FIG. 2B, and the four LEDs 205, 206, 209, and 210 are included. An LED block 302 is composed of LEDs. The LED block is a light source block composed of a plurality of light sources, and the backlight 110 is controlled to emit light in units of light source blocks. That is, the LED block is a control unit for light emission of the LED, and a plurality of LEDs constituting the LED block are connected to the same control channel, and the same light emission control is performed. The same operation is performed for switches (not shown) connected to the LED drivers 107 to 109. As a result, as shown in FIG. 3B, the backlight 110 is divided into a total of 24 square (rectangular) LED blocks of 6 horizontal x 4 vertical, and the light emission is controlled independently for each LED block. It becomes possible. Such an arrangement of the LED blocks is suitable for local dimming and unevenness correction.

  When “backlight scan mode” is selected, the backlight control unit 105 connects the switch 211 to the left terminal B and switches 212, 213, and 214 to the right as shown in FIG. Each switch is switched to connect to terminal A. When the switches are switched in this way, the LEDs 206, 205, 204, and 203 are connected in series to the first control channel 201 of the LED driver 106, and these four LEDs are supplied with voltage from the voltage supply terminal 216. The Further, LEDs 210, 209, 208, and 207 are connected in series to the second control channel 202 of the LED driver 106, and these four LEDs are supplied with a voltage from a voltage supply terminal 217.

  At this time, as shown in FIG. 4B, the LED block 401 is composed of the four LEDs 207, 208, 209, and 210 in FIG. 2B, and the four LEDs 203, 204, 205, and 206 are included. An LED block 402 is composed of LEDs. The same operation is performed for switches (not shown) connected to the LED drivers 107 to 109. As a result, as shown in FIG. 4B, the backlight 110 is divided into a total of 24 rectangular (line) LED blocks of 3 horizontal x 8 vertical, and the light emission is controlled independently for each LED block. It becomes possible. In such an LED block arrangement, when the backlight scan is performed, it is possible to change the lighting start and extinguishing timing for each LED line, so that the backlight scan is highly effective in improving the motion blur. be able to.

As described above, according to the image display apparatus of the present embodiment, the shape of the LED block that divides the backlight can be changed to a square (rectangular) shape or a rectangular (line) shape by switching the switch. Therefore, it is possible to perform light emission control using an optimal LED block by performing the above switch control according to backlight control such as local dimming, unevenness correction, and backlight scanning. Therefore, more effective backlight control can be performed. In addition, since a plurality of LEDs are connected in series to the control channel of each LED driver, optimal LED light emission control according to backlight control is performed while suppressing an increase in the number of LED drivers to be used. It becomes possible.
In addition, although the case where the shape of the LED block is a square shape is illustrated at the time of local dimming control or unevenness correction, the shape is not limited to the square shape, and the rectangular shape is closer to the square than the rectangular shape at the time of backlight scanning. If it is. For example, the shape of the LED block at the time of local dimming control or unevenness correction may be a rectangular shape composed of 3 horizontal x 2 vertical LEDs, or a rectangular shape composed of 2 horizontal x 3 vertical LEDs. Good.

(Example 2)
In the second embodiment, a method of performing more precise local dimming in the image display apparatus having the LED and switch configurations described in the first embodiment will be described.

  As shown in FIG. 5A, consider a case where image data including a high luminance image 501 and a low luminance image 502 is input to the image display device 100. In normal local dimming, the brightness of each LED block is finely adjusted to a plurality of levels according to the brightness of image data in the display area corresponding to each LED block of the LCD panel 103. However, here, for simplification of explanation, the luminance of each LED block is adjusted to two levels of luminance, “high luminance lighting” and “low luminance lighting”, according to the luminance of the image data of the corresponding display area. Shall. In the example of FIG. 5A, the LED block corresponding to the high brightness image 501 is turned on with high brightness, and the LED block corresponding to the low brightness image 502 is turned on with low brightness.

  In addition, when the high luminance portion and the low luminance portion are mixed in the image data of the display area of the LCD panel 103 corresponding to a certain LED block, the luminance of the LED block is adjusted according to the image data of the high luminance portion. Shall. In the example of FIG. 5A, when both the high luminance image 501 and the low luminance image 502 exist in the display area of the LCD panel 103 corresponding to a certain LED block, the LED block is turned on with high luminance.

  Among the LEDs of the backlight 110 shown in FIG. 5B, the LEDs 511, 512, 513, 514, 515, 516, 517, and 518 hit the boundary between the high-intensity image 501 and the low-intensity image 502. It needs to be lit. On the other hand, since the LEDs 503, 504, 505, 506, 507, 508, 509, and 510 hit the low-brightness image 502, these LEDs should be turned on with low-brightness.

  However, when the switches connected to all the control channels of all the LED drivers are switched to the state shown in FIG. 3A and the LED block is as shown in FIG. Belong to the same LED block 519 as the LEDs 511 and 512. Since both the high brightness image 501 and the low brightness image 502 exist in the display area of the LCD panel 103 corresponding to the LED block 519, the LED block 519 is turned on with high brightness. Similarly, the LED blocks 520, 521, and 522 are turned on with high brightness. Then, the LEDs 503, 504, 505, 506, 507, 508, 509, and 510 are turned on with high luminance, but the image displayed in the display area of the LCD panel 103 corresponding to these LEDs is a low luminance image. Therefore, there is a possibility that the black float will be noticeable in this display area.

  Therefore, in this embodiment, the backlight control unit 105 changes the switch switching method for each LED switching group according to the image data. As a result, the backlight control unit 105 controls the backlight 110 so that a square (rectangular) LED block and a rectangular (line) LED block are mixed and the backlight is optimally turned on. The LED switching group is a group of a predetermined number (here, two) of control channels whose connection states are switched by a switch, voltage supply terminals and LEDs connected to the control channel. In the example of FIG. 2A, the control channels 201 and 202, LEDs 203 to 210, switches 211 to 214, and voltage supply terminals 215 to 217 form one LED switching group.

  In this embodiment, it is assumed that all 8 LEDs of 4 horizontal x 2 vertical shown by the thick frame in FIG. 2B are LED switching groups. Eight LEDs constituting one LED switching group are divided into two square-shaped LED blocks consisting of 2 horizontal x 2 vertical LEDs or 4 horizontal x vertical by switching the switch. It is divided into two rectangular LED blocks each consisting of one LED. Whether the eight LEDs constituting one LED switching group are divided into square LED blocks or rectangular LED blocks can be determined independently for each LED switching group.

  In the example of FIG. 5B, the LEDs 503, 505, 506, 507, 511, 512, 513, 514 belong to the same LED switching group 51. Further, the LEDs 507, 508, 509, 510, 515, 516, 517, 518 belong to the same LED switching group 52.

When the image data of FIG. 5A is input, the backlight control unit 105 divides the LED switching groups 51 and 52 into rectangular LED blocks, and the other LED switching groups are square LEDs. Divide into blocks. That is, the backlight control unit 105 switches the LED switching groups 51 and 52 to the switch state as shown in FIG. 4A, and the remaining LED switching groups to the switch state as shown in FIG. .

  Then, as shown in FIG. 6A, the LEDs 503, 504, 505, and 506 constitute the LED block 601, and the LEDs 507, 508, 509, and 510 constitute the LED block 602. The LEDs 511, 512, 513, and 514 constitute an LED block 603, and the LEDs 515, 516, 517, and 518 constitute an LED block 604. When the backlight 110 is divided by such LED blocks, when the luminance of each LED block is determined according to the image data in FIG. 5A, the LED blocks 601 and 602 have low luminance as shown in FIG. 6B. The LED blocks 603 and 604 are turned on with high brightness. In this case, unlike the case of FIG. 5C, the LEDs 503, 504, 505, 506, 507, 508, 509, and 510 are lit at a low luminance. Therefore, in the display area of the LCD panel 103 corresponding to these LEDs. The black float can be suppressed.

  As described above, it is possible to perform precise local dimming control by setting the LED block for each LED switching group according to the image data. In the above-described embodiment, the example in which the division method by the LED block of the plurality of LEDs belonging to the LED switching group is switched in two ways by switching the switches has been described. However, the number of types of division methods using LED blocks that can be switched by switching the switches may be three or more. In addition, as the shape of the LED block, a square (rectangular) shape and a horizontally long rectangular (line) shape are illustrated. The reason for having a horizontally long rectangular shape is that the direction perpendicular to the scanning direction in the backlight scan is the longitudinal direction. In addition, the division | segmentation of the backlight by LED blocks of other shapes, such as a vertically long rectangular shape (when a backlight scanning direction is a horizontal direction), is also considered.

105 Backlight controller
106,107,108,109 LED driver
110 Backlight
201, 202 LED control channel
203, 204, 205, 206, 207, 208, 209, 210 LED
211, 212, 213, 214 switch

Claims (9)

Multiple light sources;
A plurality of driving means for driving the light source,
With
A plurality of light sources are connected to each driving means, and each driving means drives a plurality of connected light sources with the same drive signal, thereby forming a light source composed of a plurality of light sources connected to the same driving means. A backlight device in which light emission is controlled in units of blocks,
A plurality of switches for switching the connection between the driving means and the light source, the connection between the plurality of light sources connected to the driving means, and the connection between the light source and the power source that supplies power to the light source;
Control for changing the shape of a light source block composed of light sources connected to each driving means by changing each of the switches to change a driving means to which at least some of the light sources are connected. Means,
Equipped with a,
The control means, the shape of the light source block, a square shape to a rectangular shape, or a backlight device from the rectangular Ru changing to a square shape. When the control means performs local dimming control for controlling the driving means so that the luminance of each light source block is in accordance with the image data of the area corresponding to each light source block, the shape of the light source block is a square shape. the backlight apparatus of claim 1 for switching the switch to become. The control means controls the drive means so that the luminance of each light source block becomes a luminance according to the light emission characteristics of the light source of each light source block to reduce unevenness in luminance among a plurality of light source blocks. 3. The backlight device according to claim 2 , wherein when the operation is performed, the switch is switched so that the shape of the light source block is a square shape. When the control means performs backlight scan control for controlling the driving means so that lighting and extinction of each light source block is switched in accordance with scanning of the liquid crystal panel illuminated by the backlight device, the shape of the light source block The backlight device according to claim 2 , wherein the switch is switched so that the switch has a rectangular shape in which the direction perpendicular to the scan direction is the longitudinal direction. The switch is provided for each group of a predetermined number of driving means and a plurality of light sources connected to the driving means, and a plurality of light sources belonging to each group is switched by switching a switch belonging to each group to a predetermined position. At least a portion of the light source of the connected drive means, the backlight device according to any one of claims 1 to 4 is switched to a different drive means ones of the drive means belonging to each group of. The backlight device according to claim 5 , wherein switching of the switch is performed independently for each group. The control means performs local dimming control for controlling the driving means so that the luminance of each light source block corresponds to the image data of the area corresponding to each light source block. The backlight device according to claim 6 , wherein the switch is switched. The backlight device according to any one of claims 1 to 7 ,
A liquid crystal panel illuminated by the backlight device;
An image display device comprising: Multiple light sources;
A plurality of driving means for driving the light source,
With
A plurality of light sources are connected to each driving means,
A method for controlling a backlight device comprising a plurality of switches for switching between a drive means and a light source, a connection between a plurality of light sources connected to the drive means, and a connection between a light source and a power source that supplies power to the light source. And
By switching each of the switches, the driving means to which at least some of the plurality of light sources are connected is changed, and the shape of the light source block constituted by the light sources connected to the driving means is changed to a square shape. Changing from a rectangular shape to a rectangular shape or from a rectangular shape to a square shape;
After changing the shape of the light source block, each driving unit drives a plurality of light sources to be connected with the same driving signal, whereby a light source block unit composed of a plurality of light sources connected to the same driving unit and controlling the light emission in,
Control method for a backlight device having a.

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