JP2013171258A - Backlight driving device and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress display blurring and flickering in a display panel.SOLUTION: A backlight driving circuit 118 drives a backlight unit 104 having a plurality of backlight light sources 202 provided side by side in a vertical scanning direction of a display panel 102. The backlight driving circuit 118 synchronizes each of the backlight light sources 202 corresponding to a scan lighting region of the display panel 102 with a period in which a pixel row corresponding to the backlight light sources 202 in the display panel 102 is scanned, and includes a light emission control unit 119 for sequentially emitting light.

Description

  The present invention relates to a backlight driving device and a display device.

  In recent years, in various information terminals such as an electronic book terminal, a smart phone, a mobile phone, a PDA (portable information terminal), a tablet terminal, a laptop personal computer, a portable game machine, and a car navigation device, a liquid crystal display device or the like is relatively Thin display devices are often used. In such a display device, reducing power consumption and improving display image quality are common problems. Therefore, conventionally, various techniques have been devised with respect to display devices for the purpose of solving such problems.

  For example, in a general liquid crystal display device, a method of always lighting a backlight is adopted. In such a liquid crystal display device, a so-called display blur occurs due to an afterimage of a past frame image and an image in the middle of a response of a liquid crystal element, particularly when a fast moving video is displayed due to a delay in the liquid crystal response time. There is a problem.

  Therefore, as a technique for solving such a problem, the following cited document 1 discloses that a backlight light source is divided into a plurality of light emitting areas, and the horizontal scanning is completed each time an image writing scan in a horizontal line group is completed. A technique is disclosed in which a plurality of light emitting areas are sequentially turned on within one frame period by lighting a light emitting area corresponding to a line group. According to this technique, it is said that display blur as described above can be prevented.

International Publication No. 2004/053826 (Publication Date: June 24, 2004)

  However, in the technique disclosed in Patent Document 1, the lighting cycle of each light emitting area is synchronized with the frame frequency of the display panel. Flickering), and the flickering of the display panel is easily visually recognized. That is, with the technique disclosed in Patent Document 1, even if the occurrence of display blur in the display panel can be suppressed, the occurrence of flicker in the display panel cannot be suppressed together with this.

  The present invention has been made in view of the above-described problems, and an object thereof is to suppress flickering in a display panel while suppressing display blur in the display panel.

  In order to solve the above-described problems, a backlight driving device according to the present invention is a backlight driving device that drives a backlight device having a plurality of backlight light sources arranged in parallel along the vertical scanning direction of the display panel. Then, among the plurality of backlight light sources, each of the plurality of backlight light sources corresponding to the first display area of the display panel is scanned for a pixel row corresponding to the backlight light source on the display panel. And a light emission control means for sequentially emitting light in synchronism with each other.

  According to the backlight driving device, each of the plurality of backlight light sources is sequentially turned on in synchronization with the scanning period of the corresponding pixel row, whereby an afterimage of the past frame image and an image in the middle of the response of the liquid crystal element are obtained. Since it becomes difficult to be visually recognized, display blur can be prevented.

  In particular, since such a backlight light source control is performed for the first display area, which is a part of the display area of the display panel, the area of the display area that is likely to flicker is minimized, and the display panel Flickering can be made difficult to see. Therefore, according to the backlight driving device, it is possible to suppress flickering in the display panel while suppressing display blur in the display panel.

  In the driving apparatus, the light emission control unit includes a plurality of backlight light sources corresponding to a second display area that is different from the first display area in the vertical scanning direction among the plurality of backlight light sources. It is preferable that each of them always emit light.

  According to this configuration, since the flicker does not occur in the other display areas by constantly turning on the backlight light source, it is possible to make the flicker of the display panel less visible.

  In the driving apparatus, the first display area is an upper display area of the display panel and a lower display area of the display panel, and the second display area is a central display area of the display panel. Is preferred.

  According to this configuration, since the backlight light source corresponding to the central display area of the display panel, which is a display area that is easily visible by the user, is always turned on, the flickering of the display panel can be made less visible.

  In the driving apparatus, it is preferable that the first display area and the second display area are alternately provided on the display panel.

  According to this configuration, the first display area where the flicker is likely to occur and the second display area where the blur is likely to occur are alternately arranged, so that the display blur and the flicker are distributed over the entire surface of the display panel. Display blur and flicker can be made difficult to be visually recognized.

  In the driving apparatus, it is preferable that the first display area is a display area in which an image determined as an image in which display blur is likely to occur is displayed.

  According to this configuration, it is possible to appropriately and minimize the first display area in which display blur is unlikely to occur but flicker is likely to occur. Therefore, it is possible to make the display panel flicker less visible while suppressing display blur more appropriately.

  In the driving device, it is preferable that the light emission control unit expands an area of the second display region as a frame frequency of an image displayed on the display panel is lowered.

  According to this configuration, even if flickering in the first display area becomes easy to be visually recognized due to the decrease in the frame frequency, the area of the first display area is relatively reduced. Can be made difficult to be visually recognized.

  In the driving device, it is preferable that at least one of the first display area and the second display area is a display area designated by a user.

  According to this configuration, it is possible to appropriately set the first display area where display blur should be suppressed and the second display area where flicker should be suppressed.

  In the driving apparatus, the light emission control unit causes each of the plurality of backlight light sources corresponding to the second display area to emit light intermittently at a frequency of 60 Hz or more among the plurality of backlight light sources. Is preferred.

  According to this configuration, it is possible to suppress display blur in the second display area by blinking the corresponding backlight light source. Thereby, the suppression effect of the display blur of a display panel can be heightened more. In particular, flickering of the backlight light source can be suppressed by blinking the backlight light source at a frequency of 60 Hz or higher.

  In the driving device, the light emission control unit individually controls the light emission amount of the backlight light source corresponding to the first display region and the light emission amount of the backlight light source corresponding to the second display region. Preferably it is possible.

  According to this configuration, it is possible to flexibly control the brightness of the display panel while making it possible to achieve the same effects (display blur suppression effect, flicker prevention effect, etc.) as the above drive device. For example, the brightness unevenness of the display panel can be suppressed by making the brightness of the display panel uniform.

  The display device according to the present invention includes a display panel having a plurality of pixels, a backlight device having a plurality of backlight light sources arranged in parallel in a direction corresponding to the vertical scanning direction of the display panel, and the backlight. And a driving device.

  According to this display device, the same effect as the backlight driving device can be obtained.

  In the display device, an oxide semiconductor is preferably used for a semiconductor layer of a switching element included in each of the plurality of pixels. In particular, in the display device, the oxide semiconductor is preferably IGZO.

  According to this configuration, the ON and OFF characteristics of each pixel are very excellent, and the refresh rate can be easily increased or decreased easily. Therefore, display blur and flicker are likely to occur. The need to suppress flickering increases. For this reason, the present invention can be more effective when applied to such a display device.

  ADVANTAGE OF THE INVENTION According to this invention, the flicker in a display panel can be suppressed, suppressing the display blur in a display panel.

1 is a block diagram illustrating a schematic configuration of a television according to Embodiment 1. FIG. The structure of the backlight unit with which the television concerning Embodiment 1 is provided is shown. 4 is a timing chart showing light emission timing of a backlight light source in the television according to the first embodiment. The relationship between the frame frequency of the video signal and the area of the central display area in the television according to the first embodiment is shown. It is a block diagram which shows schematic structure of the television which concerns on Embodiment 2. FIG. The arrangement | positioning of the various display areas in the display panel of the television which concerns on Embodiment 3 is shown. 10 is a timing chart showing light emission timing of a backlight light source in the television according to the third embodiment. The arrangement | positioning of the various display area in the display panel of the television which concerns on Embodiment 4 is shown. 6 is a timing chart showing light emission timing of a backlight light source in the television according to the fourth embodiment. FIG. 10 is a block diagram illustrating a schematic configuration of a television according to a fifth embodiment. 14 is a timing chart showing light emission timing of a backlight light source in the television according to the sixth embodiment. FIG. 16 shows the light emission amount and supply current of each display area in a television according to Embodiment 7. FIG. The amount of light emission of each display area and the number of light emitting elements in the television according to Embodiment 7 are shown. It is a figure which shows the characteristic of various TFT including the TFT using an oxide semiconductor.

(Embodiment 1)
Embodiments according to the present invention will be described below with reference to the drawings. First, Embodiment 1 according to the present invention will be described. In the first embodiment, an example in which the present invention is applied to a television receiver having a function as a display device will be described.

(TV configuration)
First, the configuration of the television 100 according to the first embodiment will be described with reference to FIG. FIG. 1 is a block diagram illustrating a schematic configuration of a television 100 according to the first embodiment.

  A television 100 shown in FIG. 1 is a so-called television receiver. For example, the television 100 can receive television broadcast waves such as terrestrial digital broadcast, BS digital broadcast, and CS digital broadcast. The television 100 can allow the user to view the program content by playing back the program content included in the received television broadcast wave.

  As shown in FIG. 1, the television 100 includes a display panel 102, a backlight unit 104, a display driving circuit 110, a video processing circuit 120, a tuner 106, and an HDMI interface 108.

(Display panel)
The display panel 102 displays various videos such as program content reproduced on the television 100. The display panel 102 employs a so-called active matrix type liquid crystal display panel. That is, the display panel 102 includes a plurality of TFT liquid crystal pixels, a plurality of gate signal lines, and a plurality of source signal lines.

  The plurality of TFT liquid crystal pixels are arranged in a so-called lattice shape including a plurality of pixel columns and a plurality of pixel rows. The gate signal line is provided for each pixel row. Each gate signal line is electrically connected to each TFT liquid crystal pixel in the corresponding pixel row, and is provided to supply a gate signal sent from the scanning line driving circuit 114 to each TFT liquid crystal pixel. It has been. A source signal line is provided for each pixel column. Each source signal line is electrically connected to each TFT liquid crystal pixel in the corresponding pixel column, and is provided to supply a source signal sent from the signal line driving circuit 116 to each TFT liquid crystal pixel. It has been.

  In the present embodiment, the nth pixel row from the top is expressed as a pixel row (n). For example, the top pixel row is expressed as a pixel row (1), and the second pixel row from the top is expressed as a pixel row (2). A gate signal line for driving the pixel row (n) (that is, the nth gate signal line from the top) is expressed as a gate signal line (n). For example, a gate signal line for driving the pixel row (1) is expressed as a gate signal line (1), and a gate signal line for driving the pixel row (2) is expressed as a gate signal line (2). To do.

(Backlight unit)
The backlight unit 104 is provided on the back side of the display panel 102. The backlight unit 104 irradiates the display panel 102 with backlight light from the back side. In the display panel 102, the amount of transmission of the backlight light is adjusted for each TFT liquid crystal pixel in accordance with the video signal under the control of the display driving circuit 110. As a result, a video corresponding to the video signal is displayed on the display panel 102.

(Display drive circuit)
The display drive circuit 110 drives the display panel 102 and the backlight unit 104 according to the input video signal, thereby causing the display panel 102 to display a video corresponding to the video signal. As described above, in the present embodiment, an active matrix liquid crystal display panel is employed as the display panel 102. Accordingly, as shown in FIG. 1, the display driving circuit 110 includes a timing controller 112, a scanning line driving circuit 114, a signal line driving circuit 116, and a backlight driving circuit 118. .

(Timing controller)
A video signal is input from the video processing circuit 120 to the timing controller 112. For example, the video signal includes a clock signal, a synchronization signal, an image data signal, and the like. Then, the timing controller 112 operates each driving circuit (the scanning line driving circuit 114, the signal line driving circuit 116, and the backlight driving circuit 118) in synchronization with each other according to the video signal, and the video corresponding to the video signal. Are output to each of the driving circuits.

(Scanning line drive circuit)
The scanning line driving circuit 114 sequentially selects and scans a plurality of gate signal lines. Specifically, the scanning line driving circuit 114 sequentially selects a plurality of gate signal lines one by one, and applies an ON voltage (that is, supplies a gate signal) to the selected gate signal line. Thereby, in each TFT liquid crystal pixel on the gate signal line, the switching element (TFT) is switched ON.

(Signal line drive circuit)
While the gate signal line is selected, the signal line driving circuit 116 supplies a source signal corresponding to the image data from the corresponding source signal line to each TFT liquid crystal pixel on the gate signal line. Specifically, the signal line drive circuit 116 calculates the value of the voltage to be output to each TFT liquid crystal pixel on the selected gate signal line based on the input video signal, and uses the voltage of the value as a source. Output from the output amplifier (not shown) toward each source signal line. As a result, a source signal is supplied to each TFT liquid crystal pixel on the selected gate signal line, and this source signal is written.

(Backlight drive circuit)
The backlight driving circuit 118 causes the backlight unit 104 to emit light by driving the backlight unit 104. The backlight drive circuit 118 includes a light emission control unit 119. The light emission control unit 119 controls the light emission timing of the backlight unit 104. Although details will be described later, for example, the light emission control unit 119 can control the light emission timing of each of the plurality of backlight light sources 202 included in the backlight unit 104.

(Video processing circuit)
The video processing circuit 120 receives the video signal supplied from the tuner 106 and the HDMI interface 108. For example, the tuner 106 receives a video signal of video content broadcast from a broadcasting station. Also, the HDMI interface 108 receives a video signal of video content reproduced by an external device (not shown).

  Then, the video processing circuit 120 generates and generates a video signal (that is, a video signal including a clock signal, a synchronization signal, an image data signal, etc.) to be supplied to the display driving circuit 110 from the received video signal. The video signal is output to the display driving circuit 110.

  The video processing circuit 120 includes a video discrimination unit 122. The video discriminating unit 122 discriminates various feature points in the video signal. For example, the video determination unit 122 determines the frame frequency of the video signal. Various feature points determined by the video processing circuit 120 are notified to the backlight driving circuit 118 via the timing controller 112.

  The video signal input system to the video processing circuit 120 is not limited to the tuner 106 and the HDMI interface 108. For example, a video signal may be input from an external device interface different from the HDMI interface, a communication interface, a playback unit that plays back video content recorded on the HDD, or the like.

(Configuration of backlight unit)
Next, the configuration of the backlight unit 104 will be described with reference to FIG. FIG. 2 shows a configuration of the backlight unit 104 included in the television 100 according to the first embodiment. Further, FIG. 2 conceptually shows a state in which the display panel 102 is provided on the front side of the backlight unit 104.

  Here, for easy understanding, the display panel 102 provided with 18 pixel rows and the backlight unit 104 provided with nine backlight light sources 202 are illustrated. In practice, more gate signal lines and more backlight sources may be provided.

  The backlight unit 104 includes a plurality of backlight light sources 202 (backlight light sources 202A to 202F). Each backlight light source 202 is elongated with the horizontal direction (direction corresponding to the pixel row direction of the display panel 102) as the long direction and the vertical direction (direction corresponding to the pixel column direction of the display panel 102) with the short direction. It has a rectangular shape. The plurality of backlight light sources 202 are provided side by side in the vertical direction. Thereby, the backlight unit 104 can irradiate the backlight light to substantially the entire display area of the display panel 2.

  Each backlight light source 202 includes a light emitter such as an LED (Light Emitting Diode) or a CCFL (Cold Cathode Fluorescent Lamp). For example, when an LED is used for the light emitter, each backlight light source 202 includes a plurality of LEDs arranged on a substrate. When each backlight light source 202 is thin, a light guide plate for uniformly irradiating the display panel 102 with light emitted from the light emitter is provided, and the light emitter is It may be provided on either side of the light guide plate.

  Each backlight light source 202 emits light using electric power supplied from a power supply circuit (not shown) included in the television 100. The timing at which each backlight light source 202 emits light is controlled by the light emission control unit 119 of the backlight drive circuit 118. Each backlight light source 202 can emit light independently under the control of the light emission control unit 119.

(Light emission control by backlight drive circuit)
For the backlight unit 104 configured as described above, the light emission control unit 119 of the backlight driving circuit 118 can control the light emission timing of each of the plurality of backlight light sources 202. That is, the light emission control unit 119 can cause any backlight light source 202 to emit light alone.

  Of course, the light emission control unit 119 can cause any plurality of backlight light sources 202 to emit light independently of the other backlight light sources 202, or can also cause all the backlight light sources 202 to emit light simultaneously. .

  In particular, the light emission control unit 119 can cause a specific backlight light source 202 to emit light in synchronization with the timing at which the corresponding pixel row is scanned. The “pixel row corresponding to the backlight light source 202” means a pixel row to which the backlight light from the backlight light source 202 can be irradiated. In general, the backlight light source 202 is provided on the back side. Means a pixel row.

  The timing at which the pixel row is scanned is determined by a horizontal synchronization signal supplied from the timing controller 112. Therefore, for example, the light emission control unit 119 can synchronize the timing at which the pixel row is scanned and the timing at which the backlight light source 202 corresponding to the pixel row emits light based on the horizontal synchronization signal.

  For this purpose, the television 100 associates several pixel rows with each backlight light source 202 in advance. Then, the television 100 stores information indicating this association in advance in a memory or the like provided in the television 100. The light emission control unit 119 can specify the backlight light source 202 corresponding to each pixel row by referring to the information.

(Example of control of light emission timing of backlight light source)
Hereinafter, the light emission timing of the backlight light source 202 in the television 100 according to the first embodiment will be described with reference to FIG. FIG. 3 is a timing chart showing the light emission timing of the backlight light source 202 in the television 100 according to the first embodiment.

  FIG. 3 shows the drive timing of each gate signal line and the light emission timing of each backlight light source 202 in one frame period as pulse waveforms of drive pulses.

  In FIG. 3, Vsync indicates a vertical synchronization signal generated every frame period. That is, the value of Vsync is ON (Hi level) for one frame period.

  Vg (1) to (18) indicate drive pulses for the gate signal lines (1) to (18). That is, each of Vg (1) to (18) is turned on (Hi level), and the corresponding gate signal line is scanned.

  Vl (1) to (9) indicate drive pulses of the backlight light sources 202A to 202I (see FIG. 2). That is, when each of Vl (1) to (9) is turned ON (Hi level), the corresponding backlight light source 202 is driven.

  As indicated by Vg (1) to Vg (18) in FIG. 3, the gate signal lines (1) to (18) are sequentially scanned one by one in one frame period.

  On the other hand, the plurality of backlight light sources 202 are driven as follows in one frame period.

(1. Association between backlight source and pixel row)
As described above, the television 100 associates several pixel rows with each backlight light source 202 in advance. In this embodiment, nine backlight light sources 202 are provided, whereas the display panel 102 has 18 pixel rows. In response to this, the television 100 associates two pixel rows with each backlight light source 202. For example, a pixel row (1) and a pixel row (2) are associated with the backlight light source 202A, and a pixel row (3) and a pixel row (4) are associated with the backlight light source 202A.

  In this embodiment, since the vertical size of each backlight light source 202 is the same, the number of pixel rows associated with each backlight light source 202 is the same, but the size and irradiation range of each backlight light source 202 are the same. If they are different from each other, the number of pixel rows associated with each backlight light source 202 may be different.

(2. Classification of backlight source)
The light emission control unit 119 classifies the plurality of backlight light sources 202 in advance into a backlight light source 202 that is turned on by scanning and a backlight light source 202 that is always turned on.

  For example, in the example illustrated in FIG. 2, the display area of the display panel 102 includes an upper display area, a central display area, and a lower display area.

  In the central display area, in controlling the light emission timing of the backlight light source 202 in the television 100, the corresponding backlight light source 202 is not scanned in order to prioritize flicker prevention over display blur prevention (that is, This is a display area that is always lit. Hereinafter, such a display area is referred to as “always-on area”.

  On the other hand, in the upper display area and the lower display area, in controlling the light emission timing of the backlight light source 202 in the television 100, in order to prioritize the prevention of display blur over the prevention of flicker, This is a display area to be lit for scanning. Hereinafter, such a display area is referred to as a “scan lighting area”.

  For example, in the example shown in FIG. 2, the upper display area including the pixel rows (1) to (6) is set as the scan lighting area. Further, the lower display area including the pixel rows (13) to (18) is set as a scan lighting area (first display area). The central display region including the pixel rows (7) to (12) is set as a constantly lit region (second display region having a position in the vertical scanning direction different from that of the first display region).

  As described above, in response to the setting of each display area, the light emission control unit 119 sets, for each display area, the backlight light source 202 that scans the backlight light source 202 and the backlight that always lights. The light source 202 is classified.

  For example, in the example shown in FIG. 2, the backlight light sources 202A to 202C disposed at positions corresponding to the upper display area, and the backlight light sources 202G to 202I disposed at positions corresponding to the lower display area. Is selected as the backlight light source 202 to be scanned. And the backlight light sources 202D-F arrange | positioned in the position corresponding to the said center part display area are selected as the backlight light source 202 always lighted.

(3. Light emission control of backlight light source)
The light emission control unit 119 sequentially emits the plurality of backlight light sources 202 to be lit in synchronization with a period during which the corresponding pixel row is scanned on the display panel 102. On the other hand, the light emission control unit 119 causes the plurality of backlight light sources 202 that are constantly lit to emit light until all the pixel rows are scanned on the display panel 102 (that is, one frame period).

(3.1. Light emission control of backlight light source corresponding to upper display area)
For example, backlight light sources 202 </ b> A to 202 </ b> C correspond to the upper display area of the display panel 102, and the backlight light sources 202 </ b> A to 202 </ b> C are classified as the backlight light sources 202 that are turned on by scanning. Among these, pixel row (1) and pixel row (2) are assigned to backlight light source 202A. Accordingly, the light emission control unit 119 causes the backlight source 202A to emit light in synchronization with the horizontal scanning period in which the pixel row (1) is scanned and the horizontal scanning period in which the pixel row (2) is scanned. Similarly, the light emission control unit 119 causes the backlight source 202B to emit light in synchronization with the horizontal scanning period in which the pixel row (3) is scanned and the horizontal scanning period in which the pixel row (4) is scanned, and thereby the pixel row. The backlight source 202C is caused to emit light in synchronization with the horizontal scanning period during which (5) is scanned and the horizontal scanning period during which the pixel row (6) is scanned. Thereby, the backlight light sources 202A to 202C emit light sequentially in synchronization with the horizontal scanning period in which the pixel row (1) is scanned to the horizontal scanning period in which the pixel row (6) is scanned (FIG. 3). Vl (1) to (3)).

(3.2. Light emission control of backlight light source corresponding to lower display area)
In addition, backlight light sources 202G to 202I correspond to the lower display area of the display panel 102, and the backlight light sources 202G to 202I are classified as the backlight light sources 202 that are turned on by scanning. Among these, the pixel row (13) and the pixel row (14) are assigned to the backlight source 202G. Therefore, the light emission control unit 119 causes the backlight source 202G to emit light in synchronization with the horizontal scanning period in which the pixel row (13) is scanned and the horizontal scanning period in which the pixel row (14) is scanned. Similarly, the light emission control unit 119 causes the backlight source 202H to emit light in synchronization with the horizontal scanning period in which the pixel row (15) is scanned and the horizontal scanning period in which the pixel row (16) is scanned, and the pixel row. The backlight source 202I is caused to emit light in synchronization with the horizontal scanning period during which (17) is scanned and the horizontal scanning period during which the pixel row (18) is scanned. Thereby, the backlight light sources 202G to 202 emit light sequentially in synchronization with the horizontal scanning period in which the pixel row (13) is scanned to the horizontal scanning period in which the pixel row (18) is scanned (FIG. 3). Vl (7)-(9)).

(3.3. Light emission control of the backlight light source corresponding to the central display area)
On the other hand, backlight light sources 202D to 202F correspond to the central display area of the display panel 102, and these backlight light sources 202D to 202F are classified as backlight light sources 202 that are always lit. Therefore, the light emission control unit 119 causes the backlight sources 202D to 202F to emit light during one frame period during which the pixel rows (1) to (18) are scanned. Thereby, the backlight light sources 202D to 202F always emit light during the horizontal scanning period in which the pixel row (1) is scanned to the horizontal scanning period in which the pixel row (18) is scanned (FIG. 3). Vl (4) to (6)).

(4. Display area change function)
Here, the light emission control unit 119 can change the area of each display region. Hereinafter, this point will be described in detail with reference to FIG. FIG. 4 shows the relationship between the frame frequency (horizontal axis) of the video signal and the area ratio (vertical axis) of the central display area in the display panel 102 in the television 100 according to the present embodiment.

  For example, as the frame frequency of the video signal becomes lower, each of the backlight light sources 202 to be scanned and lighted is intermittently lighted (flashed) at a lower speed. For this reason, flickering is likely to be visually recognized in the scan lighting area (in the example of FIG. 2, the upper display area and the lower display area).

  Therefore, as shown in FIG. 4, the light emission control unit 119 increases the area of the constantly lit region (in the example of FIG. 4, the central display region) as the frame frequency of the video signal decreases. That is, the area of the display area that prioritizes flicker prevention is increased. Then, the light emission control unit 119 classifies the plurality of backlight light sources 202 into the backlight light source 202 to be scanned and the backlight light source 202 to be constantly lit according to each display area after the change.

  As a result, even if the flicker is easily visible in the scan lighting region due to the lower frame frequency of the video signal, the area of the constantly lit region where flicker does not occur is widened. The effect will increase.

  There are various methods for expanding the area of the always-on region. For example, the existing constantly lit area may be expanded upward, or the existing always lit area may be expanded downward. Moreover, you may extend the existing always lighting area | region to both upward and downward. In addition to the existing always-on area (that is, on a non-continuous display area), a new always-on area may be provided.

  As already described, the frame frequency of the video signal is determined by the video determination unit 122 provided in the video processing circuit 120 and notified to the backlight drive circuit 118. Therefore, the light emission control unit 119 can specify the frame frequency of the video signal from the notification content.

(effect)
Thus, according to the television 100 of the present embodiment, afterimages of past frame images are visually recognized by sequentially lighting each of the plurality of backlight light sources 202 in synchronization with the scanning period of the corresponding pixel row. Since it becomes difficult, display blur of an image can be prevented.

  In particular, according to the television 100 of the present embodiment, not all the backlight light sources 202 are sequentially turned on, but some backlight light sources 202 are always turned on so as not to flicker. Thereby, in the display panel 102, it can suppress that a flicker is visually recognized. In particular, since the backlight light source 202 corresponding to the central display area of the display panel 102, which is a display area easily visible to the user, is always turned on, it is possible to further suppress the flickering on the display panel 102. .

  Thus, according to the television 100 of the present embodiment, both display blur and flickering on the display panel can be suppressed.

  Next, Embodiment 2 according to the present invention will be described. Hereinafter, the difference between the television 100 according to the second embodiment and the television 100 according to the first embodiment will be described, and the other points are the same as those in the first embodiment, and thus the description thereof will be omitted.

  FIG. 5 is a block diagram illustrating a schematic configuration of the television 100 according to the second embodiment. As shown in FIG. 5, the television 100 according to the present embodiment is configured to further include a display area setting circuit 130 from the configuration shown in FIG. 1.

  The display area setting circuit 130 sets an area designated by the user in the display area of the display panel 102 as a constantly lit area. As already described, the television 100 uses the central display area as a constantly lit area. Therefore, the display area setting circuit 130 sets the central display area designated by the user as a constantly lit area.

  For example, the display area setting circuit 130 causes the display panel 2 to display information for prompting the user to set the always-on area. In response to this display, the user designates the constantly lit area for the television 100 using an input device (not shown) such as a mouse, a keyboard, and a touch panel. Then, the display area setting circuit 130 outputs information indicating the designated always-on area. For example, this information indicates the start line and end line of the constantly lit area. The information is not limited to this, and information that can identify at least the constantly lit area, such as the start row of the constantly lit area and the number of rows included in the constantly lit area, may be indicated.

  The information output from the display area setting circuit 130 is input to the backlight driving circuit 118. The light emission control means 119 of the backlight drive circuit 118 identifies a central display area (that is, a constantly lit area) in the display panel 102 based on the input information.

  Then, the light emission control unit 119 identifies the display area above the identified central display area as the upper display area, and identifies the display area below the identified central display area as the lower display area.

  Thereafter, as in the first embodiment, the light emission control unit 119 classifies the backlight light sources 202 corresponding to the upper display area and the lower display area into the backlight light sources 202 that scan-light, and the backlight corresponding to the central display area. The light sources 202 are classified into backlight light sources 202 that are always turned on, and then the light emission of each backlight light source 202 is controlled.

  Note that the always-on region designated by the user may be dynamically changed according to the frame frequency of the video signal, as in the first embodiment. In addition, the constantly lit area may be reset by the user at an arbitrary timing. In addition, when the above-described constantly lit area is not designated by the user, the light emission control unit 119 may use a constantly lit area set in advance in the television 100.

  Next, Embodiment 3 according to the present invention will be described. In the third embodiment, an example in which the arrangement of the scan lighting area and the constant lighting area is different from that in the first embodiment will be described. Hereinafter, the differences between the television 100 according to the third embodiment and the television 100 according to the first embodiment will be described, and the other points are the same as those in the first embodiment, and thus the description thereof will be omitted.

  FIG. 6 shows an arrangement of various display areas on the display panel 102 of the television 100 according to the third embodiment. FIG. 7 is a timing chart showing the light emission timing of the backlight light source 202 in the television 100 according to the third embodiment.

  As shown in FIG. 6, in the television 100 of the present embodiment, the display area of the display panel 102 is configured by alternately arranging the scan lighting area and the constantly lighting area for every two pixel rows.

  For example, in the example shown in FIG. 6, a display area including pixel rows (1) and (2), a display area including pixel rows (5) and (6), and a display area including pixel rows (9) and (10). Each of the display area including the pixel rows (13) and (14) and the display area including the pixel rows (17) and (18) is set as a scan lighting area. On the other hand, a display region including pixel rows (3) and (4), a display region including pixel rows (7) and (8), a display region including pixel rows (11) and (12), and a pixel row Each of the display areas including (15) and (16) is set as a constantly lit area.

  As described above, in response to the setting of each display area, the light emission control unit 119 performs a backlight light source 202 that constantly scans a plurality of backlight light sources 202 and a backlight light source that always lights for each display area. And 202.

  For example, in the example shown in FIG. 6, the backlight light sources 202A, C, E, G, and I arranged at positions corresponding to the respective scan lighting areas are classified as the backlight light sources 202 that perform the scan lighting. Then, the backlight light sources 202B, D, F, and H arranged at positions corresponding to the respective constantly lit areas are classified as the backlight light sources 202 that are always lit.

(Light emission control of backlight light source)
In the television 100 according to the third embodiment, the light emission timing of each backlight light source 202 is as shown in FIG.

(Light emission control of the backlight light source corresponding to the scan lighting area)
For example, the backlight light sources 202A, C, E, G, and I correspond to the scan lighting regions, and the backlight light sources 202A, C, E, G, and I correspond to the backlight light source 202 that performs the scan lighting. It is classified.

  Among these, pixel row (1) and pixel row (2) are assigned to backlight light source 202A. Accordingly, the light emission control unit 119 causes the backlight source 202A to emit light in synchronization with the horizontal scanning period in which the pixel row (1) is scanned and the horizontal scanning period in which the pixel row (2) is scanned.

  Similarly, the light emission control unit 119 causes the backlight light source 202C to emit light in synchronization with the horizontal scanning period in which the pixel row (5) is scanned and the horizontal scanning period in which the pixel row (6) is scanned, and the pixel row. The backlight source 202E is caused to emit light in synchronization with the horizontal scanning period during which (9) is scanned and the horizontal scanning period during which the pixel row (10) is scanned.

  Further, the light emission control unit 119 causes the backlight light source 202G to emit light in synchronization with the horizontal scanning period in which the pixel row (13) is scanned and the horizontal scanning period in which the pixel row (14) is scanned, and the pixel row ( The backlight light source 202I is caused to emit light in synchronization with the horizontal scanning period during which 17) is scanned and the horizontal scanning period during which the pixel row (18) is scanned. (See Vl (1), (3), (5), (7), (9) in FIG. 7).

(Light emission control of the backlight light source corresponding to the constantly lit area)
On the other hand, backlight light sources 202B, D, F, and H correspond to the constantly lit areas, and the backlight light sources 202B, D, F, and H are classified as backlight light sources 202 that are always lit. .

  Therefore, the light emission control unit 119 causes the backlight sources 202B, D, F, and H to emit light during one frame period during which the pixel rows (1) to (18) are scanned. Thereby, the backlight light sources 202B, D, F, and H always emit light during the horizontal scanning period in which the pixel row (1) is scanned to the horizontal scanning period in which the pixel row (18) is scanned. (See Vl (2), (4), (6), (8) in FIG. 7).

(effect)
As described above, according to the television 100 of the present embodiment, the display lighting blur is generated by alternately arranging the scan lighting areas where the display blur is difficult to occur but the flickering easily occurs and the constantly lighting areas where the display blur is likely to occur. In addition, flickering can be distributed over the entire surface of the display panel 102, and thus display blurring and flickering can be made difficult to be visually recognized.

  Next, a fourth embodiment according to the present invention will be described. In the fourth embodiment, an example in which the arrangement of the scan lighting area and the constantly lighting area is different from that of the first embodiment will be described. Hereinafter, the differences between the television 100 according to the fourth embodiment and the television 100 according to the first embodiment will be described, and the other points are the same as those in the first embodiment, and thus the description thereof will be omitted.

  FIG. 8 shows an arrangement of various display areas on the display panel 102 of the television 100 according to the fourth embodiment. FIG. 9 is a timing chart showing the light emission timing of the backlight light source 202 in the television 100 according to the fourth embodiment.

  As shown in FIG. 8, in the television 100 of the present embodiment, a display area in which a display-prone image such as a telop image is displayed in the display area of the display panel 102 is set as a scan lighting area. ing.

  For example, in the example shown in FIG. 8, the display area including the pixel rows (15) to (18) is set as the scan lighting area. On the other hand, the display area including the pixel rows (1) to (14) is set as a constantly lit area.

  In the present embodiment, the scan lighting area is automatically specified from the video signal input to the video processing circuit 120 by the video discrimination unit 122 of the video processing circuit 120. For example, the video discriminating unit 122 calculates the movement amount per unit time of each object (for example, a character or a person) based on a plurality of frame images. Then, the video discriminating unit 122 identifies an object whose calculated movement amount is equal to or greater than a predetermined threshold as a video that is likely to cause display blur. Then, the video discriminating unit 122 identifies the area where the object is displayed as a scan lighting area in units of pixel rows.

  Here, the threshold value is stored in advance in, for example, a memory provided in the video processing circuit 120. The threshold is preferably set for each frame frequency of the video signal. This is because the degree of ease of occurrence of display blur differs depending on the frame frequency of the video signal. For example, the higher the frame frequency of the video signal, the easier the display blur occurs, so the threshold value may be reduced.

  Then, the video discriminating unit 122 notifies the light emission control unit 119 of the specified scan lighting area. As a result, the light emission control unit 119 can set a display area in which an image that easily causes display blurring is displayed as a scan lighting area, and can set other areas as constantly lighting areas.

  As described above, in response to the setting of each display area, the light emission control unit 119 performs a backlight light source 202 that constantly scans a plurality of backlight light sources 202 and a backlight light source that always lights for each display area. And 202.

  For example, in the example shown in FIG. 8, the backlight light sources 202H and I arranged at positions corresponding to the scan lighting areas are classified as the backlight light sources 202 that are scan-lit. And the backlight light sources 202A-G arrange | positioned in the position corresponding to the said always lighting area | region are classified into the backlight light source 202 always lighted.

(Light emission control of backlight light source)
In the television 100 according to the fourth embodiment, the light emission timing of each backlight light source 202 is as shown in FIG.

(Light emission control of the backlight light source corresponding to the scan lighting area)
For example, the backlight light sources 202H and I correspond to the scan lighting region, and the backlight light sources 202H and I are classified as the backlight light source 202 that performs the scan lighting.

  Among these, the pixel row (15) and the pixel row (16) are allocated to the backlight source 202H. Therefore, the light emission control unit 119 causes the backlight source 202H to emit light in synchronization with the horizontal scanning period in which the pixel row (15) is scanned and the horizontal scanning period in which the pixel row (16) is scanned. Similarly, the light emission control unit 119 causes the backlight source 202I to emit light in synchronization with the horizontal scanning period in which the pixel row (17) is scanned and the horizontal scanning period in which the pixel row (18) is scanned (FIG. 9). Vl (8), (9)).

(Light emission control of the backlight light source corresponding to the constantly lit area)
On the other hand, backlight light sources 202A to 202G correspond to the constantly lit area, and these backlight light sources 202A to 202G are classified as backlight light sources 202 that are always lit.

  Accordingly, the light emission control unit 119 causes the backlight light sources 202A to 202G to emit light during one frame period during which the pixel rows (1) to (18) are scanned. Thereby, the backlight light sources 202A to 202G always emit light in synchronization with the horizontal scanning period in which the pixel row (1) is scanned to the horizontal scanning period in which the pixel row (18) is scanned (FIG. 9). Vl (1)-(7)).

(effect)
Thus, according to the television 100 of the present embodiment, it is possible to automatically identify a display area where display blur is likely to occur, and to perform display lighting only in this display area to suppress display blur. That is, it is possible to minimize the display area where the flickering is likely to occur by adopting the scan lighting. Therefore, display blur and flicker can be more efficiently suppressed.

  Next, Embodiment 1 according to the present invention will be described. Hereinafter, the differences between the television 100 according to the fifth embodiment and the television 100 according to the fourth embodiment will be described, and the other points are the same as those in the fourth embodiment, and thus the description thereof will be omitted.

  FIG. 10 is a block diagram illustrating a schematic configuration of the television 100 according to the fifth embodiment. As illustrated in FIG. 5, the television 100 according to the present embodiment is configured to further include a display area setting circuit 132 from the configuration of the television 100 according to the fourth embodiment (see FIG. 1).

  The display area setting circuit 132 sets a display area in which display blur is likely to occur among the display areas of the display panel 102 as a scan lighting area. For example, the display area setting circuit 132 causes the display panel 2 to display information for prompting the user to set the scan lighting area. In response to this display, the user designates the scan lighting area with respect to the television 100 using an input device (not shown) such as a mouse, a keyboard, and a touch panel. Then, the display area setting circuit 132 outputs information indicating the designated scan lighting area. For example, this information indicates the start line and end line of the scan lighting area. The information is not limited to this, and information that can identify at least the scan lighting region, such as the start row of the scan lighting region and the number of rows included in the scan lighting region, may be indicated.

  The information output from the display area setting circuit 132 is input to the backlight drive circuit 118. The light emission control means 119 of the backlight drive circuit 118 identifies the scan lighting area in the display panel 102 based on the input information. Then, the light emission control unit 119 identifies a display area other than the scan lighting area as a constantly lighting area.

  Thereafter, as in the fourth embodiment, the light emission control unit 119 classifies the backlight light source 202 corresponding to the upper scan lighting area into the backlight light source 202 that scans and lights the backlight light source 202 corresponding to the constantly lighted area. After classifying the backlight light source 202 to be always turned on, the light emission of each backlight light source 202 is controlled.

  Note that the scan lighting area designated by the user may be fixed, or may be dynamically changed according to the frame frequency of the video signal, as in the first embodiment. The scan lighting area may be reset by the user at an arbitrary timing. When the user does not specify the scan lighting area, the light emission control unit 119 may use the scan lighting area set in the television 100 in advance.

  Next, a sixth embodiment according to the present invention will be described. The function of the light emission control means 119 described below can be applied to any of the first to fifth embodiments. Therefore, even if the function of the light emission control means 119 described below is combined with any of the first to fifth embodiments, the sixth embodiment can be realized.

  In the display panel 102, the light emission control unit 119 according to the sixth embodiment uses each of the plurality of backlight light sources 202 corresponding to the constantly lit area (that is, the backlight light source 202 that is always lit) in the display panel 102. During the frame period, light is emitted intermittently (that is, blinking).

  In particular, in the sixth embodiment, the blinking frequency of the backlight light source 202 that is always lit is set to 60 Hz or more. The reason is that flickering is difficult to be visually recognized by the user by setting the blinking frequency to approximately 60 Hz or more.

  FIG. 11 is a timing chart showing the light emission timing of the backlight light source 202 in the television 100 according to the sixth embodiment. In the first embodiment (FIG. 3), the backlight light sources 202D to 202F corresponding to the pixel rows (4) to (6) included in the constantly lit area are controlled so as to be constantly lit. 11), the backlight light sources 202D to 202F are controlled to be intermittently lit (see Vl (4) to (6) in FIG. 3 and Vl (4) to (6) in FIG. 11).

In particular, in the example illustrated in FIG. 11, the backlight light sources 202 </ b> D to 202 </ b> F are controlled to be turned on three times during one frame period. Therefore, for example, when the frame frequency of the video signal is 60 Hz, the blinking frequency of the backlight light sources 202D to 202F is 180 Hz. That is, when the frame frequency of the video signal is 60 Hz and the blinking frequency of the backlight light sources 202D to 202F is set to 60 Hz or more, the backlight light sources 202D to 202F are lit at least once in one frame period. Good.
(effect)
According to the television 100 of the sixth embodiment, display blur can be suppressed by blinking the corresponding backlight light source 202 in the always-on area. However, since the blinking frequency is set to 60 Hz or more, flicker is not visually recognized in the constantly lit region. Therefore, according to the television 100 of the present embodiment, display blur can be further suppressed without increasing flicker in the display panel. In particular, according to the television 100 of the present embodiment, the backlight light source 202 in the constantly lit area can blink, so that the effect of suppressing display blur can be widened, and the power consumption of the backlight unit 104 can be reduced. Can be suppressed.

  Next, a seventh embodiment according to the present invention will be described. The function of the light emission control means 119 described below can be applied to any of the first to sixth embodiments. Therefore, even if the function of the light emission control unit 119 described below is combined with any of the first to sixth embodiments, the seventh embodiment can be realized.

  The light emission control unit 119 according to the seventh embodiment can individually control the light emission amount of the backlight light source 202 corresponding to the scan lighting region and the light emission amount of the backlight light source 202 corresponding to the constantly lighted region. Thereby, the television 100 adjusts at least one of the light emission amounts even when the brightness differs between the scan lighting region and the constant lighting region due to, for example, a difference in lighting method of the backlight light source 202. By doing so, the brightness of both can be made uniform.

  For example, the light emission control means 119 can control the light emission amount of each of the backlight light sources 202 by controlling the amount of current supplied to each of the backlight light sources 202.

  Alternatively, the light emission control means 119 can control the light emission amount of each of the backlight light sources 202 by controlling the number of light emitting elements that emit light for each of the backlight light sources 202.

  Hereinafter, an example of control of the light emission amount of the backlight light source 202 by the light emission control unit 119 will be described with reference to FIGS. FIG. 12 shows the light emission amount and the supply current of each display area in the television 100 according to the seventh embodiment. FIG. 13 shows the light emission amount and the number of light emitting elements in each display area in the television 100 according to the seventh embodiment.

  In this example, as in the first embodiment (FIG. 2), the display area of the display panel 102 includes an upper display area, a center display area, and a lower display area. Further, it is assumed that the upper display area and the lower display area are set as scan lighting areas, and the central display area is set as a constant lighting area.

  FIG. 12 shows various setting values when the amount of light emitted from each backlight source 202 is controlled by controlling the amount of current supplied to the backlight source 202.

  As shown in FIG. 12, in the scan lighting region, the current amount “a” from the backlight drive circuit 118 to each backlight light source 202 so that the light emission amount of each backlight light source 202 becomes “A”. Current is supplied. On the other hand, in the constantly lit area, a current of “b” is supplied from the backlight drive circuit 118 to each backlight light source 202 so that the light emission amount of each backlight light source 202 becomes “B”. The

  Here, the light emission control means 119 of the seventh embodiment can set arbitrary values for the current amounts “a” and “b”, and thereby set the light emission amounts “A” and “B” to arbitrary values. Can be set to For example, the light emission control means 119 can change the light emission amounts “A” and “B” so that the brightness of the display panel 102 is uniform.

  For example, if the light emission amounts “A” and “B” are the same, and the scan lighting region is darker than the constantly lighted region, the light emission control unit 119 changes the light emission amount “A” to the light emission amount “B”. By making it larger, the brightness of both regions can be made equal.

  On the other hand, when the light emission amounts “A” and “B” are the same, if the scan lighting region becomes brighter than the constantly lighted region, the light emission control unit 119 converts the light emission amount “A” to the light emission amount “B”. By making it smaller than "", the brightness of both regions can be made equal.

  FIG. 13 shows various setting values in the case where the light emission amount of each backlight light source 202 is controlled by controlling the number of light emitting elements that emit light from the backlight light source 202.

  As shown in FIG. 13, in the scan lighting region, “x” light emitting elements are caused to emit light to each backlight light source 202 such that the light emission amount of each backlight light source 202 is “A”. On the other hand, in the constantly lit region, “y” light emitting elements are caused to emit light to each backlight light source 202 so that the light emission amount of each backlight light source 202 is “B”.

  Here, the light emission control means 119 of the seventh embodiment can set arbitrary values for the numbers of light emitting elements “x” and “y”, and thereby set the light emission amounts “A” and “B” as desired. Can be set to a value. For example, the light emission control means 119 can change the light emission amounts “A” and “B” so that the brightness of the display panel 102 is uniform.

  For example, when the light emission amounts “A” and “B” are the same, and the scan lighting region is darker than the constantly lighting region, the light emission control unit 119 sets the number of light emitting elements “x” to the number of light emitting elements “ By making it larger than “y”, the brightness of both regions can be made equal.

  On the other hand, when the light emission amounts “A” and “B” are the same, and the scan lighting region is brighter than the constantly lighting region, the light emission control unit 119 sets the number of light emitting elements “x” to the number of light emitting elements. By making it less than “y”, the brightness of both regions can be made equal.

  For example, the set values shown in FIGS. 12 and 13 are stored in a memory or the like provided in the backlight drive circuit 118 and read by the light emission control unit 119. Each set value may be set in advance at the time of product shipment. Each set value may be adjustable by a user after product shipment.

Further, each set value may be adjusted by the light emission control means 119 so that it automatically becomes an appropriate value. For example, each of the setting values may be automatically adjusted by the light emission control unit 119 so that the brightness of the display panel 102 becomes a specified brightness. In addition, each set value may be automatically adjusted by the light emission control unit 119 so that the brightness of the display panel 102 becomes uniform. In addition, the light emission control unit 119 changes each of the above parameters according to various parameters (for example, the frame frequency of the video signal, the area of each display region, the blinking cycle of the backlight light source, etc.) that cause the brightness of the display panel 102 to vary. The set value may be automatically adjusted.
(effect)
According to the television 100 of the seventh embodiment, it is possible to achieve the same effects (display blur suppression effect, flicker prevention effect, etc.) as in the first to sixth embodiments, and further, the brightness of the display panel 102 can be flexibly changed. Can be controlled. For example, as described above, the brightness unevenness of the display panel 102 can be suppressed by making the brightness of the display panel 102 uniform.

(Pixels of the display panel 102)
Next, the pixels of the display panel 102 included in the television 100 according to each of the above embodiments will be described.

  In the television 100 of each of the above embodiments, a TFT using a so-called oxide semiconductor is employed as each TFT of a plurality of pixels included in the display panel 102. In particular, indium (In) is used as the oxide semiconductor. A TFT using so-called IGZO (InGaZnOx) which is an oxide composed of gallium (Ga) and zinc (Zn) is employed. Hereinafter, the superiority of a TFT using an oxide semiconductor will be described.

(TFT characteristics)
FIG. 14 is a diagram illustrating characteristics of various TFTs including a TFT using an oxide semiconductor. FIG. 14 shows the characteristics of a TFT using an oxide semiconductor, a TFT using a-Si (amorphous silicon), and a TFT using LTPS (Low Temperature Poly Silicon).

  In FIG. 14, the horizontal axis (Vgh) indicates the voltage value of the ON voltage supplied to the gate in each TFT, and the vertical axis (Id) indicates the amount of current between the source and drain in each TFT.

  In particular, a period indicated as “TFT-on” in the figure indicates a period in which the TFT is in an ON state according to the voltage value of the ON voltage, and a period indicated as “TFT-off” in the figure. Indicates a period of OFF state according to the voltage value of the ON voltage.

  As shown in FIG. 14, a TFT using an oxide semiconductor has higher electron mobility in the ON state than a TFT using a-Si.

  Although not shown, specifically, a TFT using a-Si has an Id current of 1 uA at the time of TFT-on, whereas a TFT using an oxide semiconductor has its TFT-on. Id current at the time is about 20 to 50 uA.

  From this, it can be seen that a TFT using an oxide semiconductor has about 20 to 50 times higher electron mobility in the ON state than a TFT using a-Si, and has excellent ON characteristics. .

  Further, as shown in FIG. 14, a TFT using an oxide semiconductor has less leakage current in an OFF state than a TFT using a-Si.

  Although not shown, specifically, a TFT using a-Si has an Id current of 10 pA at the time of TFT-off, whereas a TFT using an oxide semiconductor is at the time of TFT-off. The Id current is about 0.1 pA.

  Therefore, TFTs using oxide semiconductors have a leakage current in the OFF state of about 1/100 that of TFTs using a-Si. You can see that

  The television 100 of each of the above embodiments employs a TFT using such an oxide semiconductor (particularly, IGZO) for each pixel.

  Accordingly, the television 100 of each of the above embodiments has excellent ON characteristics of the TFT of each pixel, so that the pixel can be driven by a smaller TFT. Therefore, the area occupied by the TFT in each pixel Can be reduced. That is, the aperture ratio in each pixel can be increased, and the backlight transmittance can be increased. As a result, a backlight with low power consumption can be adopted or the luminance of the backlight can be suppressed, so that power consumption can be reduced.

  In addition, since the television 100 of each of the embodiments has excellent ON characteristics of the TFT of each pixel, the writing time of the source signal to each pixel can be further shortened. The refresh rate can be easily increased.

  Furthermore, since the television 100 of each of the above embodiments has excellent TFT OFF characteristics of each pixel, the state in which the source signals of each of the plurality of pixels of the display panel are written is maintained for a long time. Therefore, the refresh rate of the display panel 102 can be easily lowered while maintaining high display image quality.

  That is, the television 100 according to each of the above embodiments employs a TFT using an oxide semiconductor (particularly, IGZO) for each pixel, so that the operation at a high refresh rate at which display blur is likely to occur or flickering is low. It is possible to easily realize the operation at the refresh rate. Therefore, the configuration described in each of the above embodiments is particularly useful in the television 100 of each of the above embodiments. And the television 100 of each said embodiment can have a higher effect by employ | adopting the said structure.

(Supplementary explanation)
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included in the technical scope of the present invention.

  For example, in the embodiment, an example in which the present invention is applied to a television receiver has been described. However, the present invention is not limited to an electronic book terminal, a smartphone, a mobile phone, a PDA, a tablet terminal, a laptop personal computer, a portable game machine, The present invention can be applied to various devices having a function as a display device such as a car navigation device and various home appliances, and a backlight driving circuit mounted on such a device.

  In the embodiment, the example in which the present invention is applied to a display device in which a TFT using an oxide semiconductor (particularly, IGZO) is adopted for each pixel has been described. However, the present invention is not limited thereto, and a-Si is used. The present invention can also be applied to display devices that employ other TFTs for each pixel, such as TFTs using TFTs or TFTs using LTPS.

  In each embodiment, the light emission timing of the backlight light source and the scanning timing of the corresponding pixel row are set to the same timing, but the present invention is not limited to this. For example, in implementing the present invention, the light emission timing of the backlight source may be shifted from the scanning timing of the corresponding pixel row in consideration of the liquid crystal response time of the corresponding pixel row.

  Further, the number and arrangement of the display areas (scan lighting areas and constant lighting areas) described in the embodiments are merely examples. Accordingly, in implementing the present invention, the number and arrangement of each display area may be any.

  In addition, the number and arrangement of the backlight light sources described in the embodiments are merely examples. Therefore, in implementing the present invention, the number and arrangement of the backlight light sources may be anything.

  In each embodiment, the backlight drive circuit 118 is provided in the display drive circuit 110. However, the present invention is not limited to this, and the backlight drive circuit 118 is provided outside the display drive circuit 110. May be.

  In each embodiment, the example in which the video processing circuit 120 is provided outside the display driving circuit 110 has been described. However, the present invention is not limited thereto, and the video processing circuit 120 may be provided in the display driving circuit 110. Good.

  In each embodiment, the example in which the video determination unit 122 is provided in the video processing circuit 120 has been described. However, the present invention is not limited thereto, and the video determination unit 122 may be provided outside the video processing circuit 120. Good. For example, the video processing circuit 120 may be provided in the display drive circuit 110, and in particular, may be provided in the backlight drive circuit 118.

  A backlight drive device and a display device according to the present invention include a backlight device including a plurality of backlight light sources, a display device including such a backlight device, and a backlight drive for driving such a backlight device. Available to the device.

100 Display Device 102 Display Panel 104 Backlight Unit (Backlight Device)
DESCRIPTION OF SYMBOLS 110 Display drive circuit 112 Timing controller 114 Scan line drive circuit 116 Signal line drive circuit 118 Backlight drive circuit (drive device)
119 Light emission control unit (light emission control means)
120 video processing circuit 122 video discrimination unit (video discrimination means)
130 Display area setting circuit 132 Display area setting circuit

Claims (12)

A backlight driving device for driving a backlight device having a plurality of backlight light sources arranged in parallel along the vertical scanning direction of the display panel,
Among the plurality of backlight light sources, each of the plurality of backlight light sources corresponding to the first display area of the display panel is synchronized with a period during which a pixel row corresponding to the backlight light source is scanned on the display panel. And a light emission control unit that sequentially emits light. The light emission control means includes
Of the plurality of backlight sources, each of the plurality of backlight sources corresponding to the second display region having a position in the vertical scanning direction different from that of the first display region is always caused to emit light. The backlight driving device according to claim 1. An upper display area of the display panel and a lower display area of the display panel;
The second display area is
The backlight driving device according to claim 2, wherein the backlight driving device is a central display region of the display panel. 3. The backlight driving device according to claim 2, wherein in the display panel, the first display area and the second display area are alternately provided along the vertical scanning direction. . The backlight driving apparatus according to claim 2, wherein the first display area is a display area in which an image determined as an image in which display blur is likely to occur is displayed. The light emission control means includes
6. The backlight driving device according to claim 2, wherein an area of the second display region is increased as a frame frequency of an image displayed on the display panel becomes lower. The backlight drive according to any one of claims 2 to 6, wherein at least one of the first display area and the second display area is a display area designated by a user. apparatus. The light emission control means includes
8. Each of the plurality of backlight light sources corresponding to the second display area among the plurality of backlight light sources is caused to emit light intermittently at a frequency of 60 Hz or more. The backlight driving device according to claim 1. The light emission control means includes
The light emission amount of the backlight light source corresponding to the first display region and the light emission amount of the backlight light source corresponding to the second display region can be individually controlled. The backlight drive device according to any one of 1 to 8. A display panel having a plurality of pixels;
A backlight device having a plurality of backlight light sources arranged in parallel in a direction corresponding to a vertical scanning direction of the display panel;
A display device comprising: the backlight driving device according to claim 1.   The display device according to claim 10, wherein an oxide semiconductor is used for a semiconductor layer of a switching element included in each of the plurality of pixels.   The display device according to claim 11, wherein the oxide semiconductor is IGZO.

Images