JP2008083427A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device which is thin in the thickness over the entire part of the device and in which an animation image blur of a moving image can be suppressed in a structure using one or a plurality of lamps. <P>SOLUTION: The liquid crystal display device comprises a liquid crystal display panel 3, a light transmission plate 12 arranged on the back of the liquid crystal display panel 3, and an upper side edge lamp 8 and lower side edge lamp 9 arranged adjacently to the light transmission plate 12 on the opposite two side edges of the liquid crystal display panel 3. Lamp controllers 1, 4, 5, 6, 7 perform the control to intermittently light the upper side edge lamp 8 and the lower side edge lamp 9 by associating the write timing of videos with respect to the liquid crystal display panel 3 and the lighting timing of the upper side edge lamp 8 and the lower side edge lamp 9. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device that displays an image by illuminating a liquid crystal display panel with an edge light type backlight light source, and in particular, a liquid crystal display device that prevents motion blur that occurs during moving image display by being close to impulse type display. It is about.

  In recent years, a liquid crystal display device having a liquid crystal display panel (LCD) has been widely used in place of a display monitor using a conventional cathode ray tube (CRT). However, when moving images are displayed on an impulse display CRT display monitor, so-called “moving image blur” does not occur, but when moving images are displayed on a liquid crystal display device of hold type display, moving image blur occurs in principle. Resulting in.

  As an improvement measure, for example, in the inventions disclosed in Patent Document 1 and Patent Document 2, an image signal for one frame to be displayed is written on a liquid crystal display panel, and after a predetermined time has elapsed, the 1 Alternatively, a backlight light source composed of a plurality of lamps is turned on over the entire surface (entire flash type). Further, in the inventions disclosed in Patent Document 3, Patent Document 4, Patent Document 5, and Patent Document 6, a liquid crystal display panel having a plurality of divided display areas and a light-emitting divided area corresponding to the divided display areas are provided. The backlight is sequentially turned on in accordance with the divided display area where the video is written (scanning backlight lighting method). Thus, these inventions suppress motion blur that occurs when displaying a moving image.

JP-A-9-325715 JP 2001-201763 A JP-A-11-202286 JP 2000-321551 A JP 2001-296838 A JP-A-2005-128546

  In the liquid crystal display devices described in Patent Literature 1 to Patent Literature 6, since the lamp is arranged on the back surface of the liquid crystal display panel and the liquid crystal display panel directly illuminates the liquid crystal display panel from the back surface, the liquid crystal display device has a structure. There was a problem that the entire thickness was increased.

  In the liquid crystal display devices described in Patent Documents 3 to 6, a plurality of lamps are arranged at equal intervals on the back surface of the liquid crystal display panel. This method has a problem that the manufacturing cost increases because a large number of lamps are required and the same number of inverter control circuits that individually drive and control the lamps are required. In addition, there is a problem that power consumption increases due to an increase in lamps to be driven and control circuits. Further, such an increase in power consumption causes a temperature rise in the liquid crystal display device. When the ambient temperature is high in this way, for example, when a CCFL (Cold Cathode Tube) is used for the lamp, the CCFL has a characteristic that the luminance decreases due to an increase in the ambient temperature, so that the luminance of the backlight decreases. There was a problem.

  The present invention has been made in order to solve such problems, and the liquid crystal display device is capable of suppressing moving image blurring of moving images with a thin thickness of the entire device and a structure using a small number of lamps. Is to provide.

  The liquid crystal display device according to the present embodiment includes a liquid crystal display panel, a light guide plate disposed on the back surface of the liquid crystal display panel, and two adjacent edges of the liquid crystal display panel adjacent to the light guide plate. Provided with a lamp. The lamp control unit performs control to intermittently light the lamp in association with video writing timing to the liquid crystal display panel and lighting timing of the lamp.

  The video display apparatus according to the present invention is thin in the entire apparatus and has a structure using a small number of lamps.

<Embodiment 1>
A liquid crystal display device according to this embodiment will be described with reference to FIGS. FIG. 1 is a block diagram showing a configuration of a liquid crystal display device according to the present embodiment. As shown in FIG. 1, the liquid crystal display device according to the present embodiment includes a signal processing unit 1, a signal output unit 2, a liquid crystal display panel 3, an upper duty / phase control unit 4, a lower duty / The phase control unit 5, the upper side lamp driving unit 6, the lower side lamp driving unit 7, the upper side edge lamp 8, and the lower side edge lamp 9 are provided.

  FIG. 2 is a timing chart of the vertical synchronization signal, the writing video signal, the upper lamp driving waveform, and the lower lamp driving waveform. The panel vertical synchronization signal is a vertical synchronization signal necessary for driving the liquid crystal display panel 3, and the write video signal is a video signal necessary for driving the liquid crystal display panel 3. These signals are signals input from the signal output unit 2 to the liquid crystal display panel 3. The upper side lamp drive waveform is a signal input from the upper side duty / phase control unit 4 to the upper side lamp drive unit 6. The lower lamp driving waveform is a signal input from the lower duty / phase control unit 5 to the lower lamp driving unit 7.

  The signal processing unit 1 generates a panel vertical synchronization signal and a writing video signal by performing scaling and necessary signal processing on the input video signal and the synchronization signal. Then, the signal processing unit 1 outputs these signals to the signal output unit 2 as digital signals.

  The signal output unit 2 converts the digital signal input from the signal processing unit 1 into, for example, LVDS (Low Voltage Differential Signal) and outputs the signal to the liquid crystal display panel 3. The signal processing unit 1 outputs the panel vertical synchronization signal and the write video signal to the liquid crystal display panel 3 via the signal output unit 2.

  The liquid crystal display panel 3 receives a panel vertical synchronization signal and a write video signal from the signal output unit 2. The liquid crystal display panel 3 is written with video based on these signals. As shown in FIG. 3A, the liquid crystal display panel includes an upper liquid crystal display unit 3a which is a first liquid crystal display unit obtained by dividing one liquid crystal display unit, and a second liquid crystal display unit. And a lower-side liquid crystal display unit 3b. In the present embodiment, the upper liquid crystal display unit 3a and the lower liquid crystal display unit 3b are virtually divided vertically by a center line.

  The video writing by the writing video signal is sequentially performed from the upper part of the upper liquid crystal display part 3a to the lower part of the lower liquid crystal display part 3b. Therefore, as shown in FIG. 2, the upper liquid crystal display unit 3a writes video in the first half of the cycle of the write video signal, and the lower liquid crystal display unit 3b writes video in the second half of the cycle of the signal. . In this way, the upper side liquid crystal display unit 3a and the lower side liquid crystal display unit 3b write images in different periods. In the case where it is not necessary to distinguish between the upper side liquid crystal display unit 3a and the lower side liquid crystal display unit 3b, they are hereinafter referred to as a liquid crystal display unit.

  The liquid crystal display panel 3 is a hold-type device, and holds data written in the previous frame, that is, video, until the video of the written video signal is written in the liquid crystal display unit. Then, a moving image is displayed on the liquid crystal display unit by switching the held image of the previous frame and the image of the current frame for each period of the panel vertical synchronization signal. In the present embodiment, as shown in FIG. 2, the writing video signal and the panel vertical synchronization signal are synchronized.

  As shown in FIG. 3B, the light guide plate 12 is disposed on the back surface of the liquid crystal display panel 3. In addition, the lamp is disposed adjacent to the light guide plate 12 at the upper edge and the lower edge, which are two opposite edges of the liquid crystal display panel 3. This lamp is a light source of the liquid crystal display panel 3, and is an upper edge lamp 8 which is a first lamp arranged on the upper liquid crystal display unit side and a second lamp arranged on the lower liquid crystal display unit side. And a lower side edge lamp 9. In addition, when it is not necessary to distinguish both the upper side edge lamp 8 and the lower side edge lamp 9, they will be referred to as lamps hereinafter. Light emitted from the lamp is transmitted through the light guide plate 12 and converted into surface light emission to the liquid crystal display panel 3. The liquid crystal display panel 3 is illuminated by the surface light emission.

  The liquid crystal display device according to the present embodiment is characterized by control for intermittently lighting the lamp. Hereinafter, a configuration of a lamp control unit that performs control of intermittently lighting the upper side edge lamp 8 and the lower side edge lamp 9 will be described.

  The lamp controller includes a signal processor 1, an upper duty / phase controller 4, a lower duty / phase controller 5, an upper lamp driver 6, and a lower lamp driver 7. .

  The signal processing unit 1 generates a PWM signal for controlling the upper side edge lamp 8 and the lower side edge lamp 9, and outputs the signal to the upper side duty / phase control unit 4 and the lower side duty / phase control unit 5, respectively. . The PWM signal here is synchronized with the panel vertical synchronization signal and has the same cycle as the panel vertical synchronization signal.

  The upper-side duty / phase control unit 4 shapes the PWM signal generated by the signal processing unit 1 with an arbitrary duty and phase, and generates an upper-side lamp drive waveform. Then, the upper side duty / phase control unit 4 outputs the upper side lamp driving waveform to the upper side lamp driving unit 6. Here, as shown in FIG. 2, an upper lamp driving waveform is generated so that the upper edge lamp 8 is turned off during a period in which the video of the written video signal is written in the upper liquid crystal display unit 3a. The cycle of the upper lamp drive waveform maintains the cycle of the PWM signal and has the same cycle as the panel vertical synchronization signal.

  Similarly, the lower duty / phase control unit 5 shapes the waveform of the PWM signal generated by the signal processing unit 1 with an arbitrary duty and phase, and generates a lower lamp driving waveform. Then, the lower duty / phase control unit 5 outputs the lower lamp driving waveform to the lower lamp driving unit 7. Here, as shown in FIG. 2, the lower lamp driving waveform is generated so that the lower edge lamp 9 is turned off during the period in which the video of the writing video signal is written in the lower liquid crystal display section 3b. The cycle of the lower side lamp drive waveform maintains the cycle of the PWM signal and has the same cycle as the panel vertical synchronization signal. In the case where it is not necessary to distinguish both the upper side lamp driving waveform and the lower side lamp driving waveform, they are hereinafter referred to as lamp driving waveforms.

  The upper side lamp driving unit 6 drives the upper side edge lamp 8 that is a light source of the liquid crystal display panel 3 based on the upper side lamp driving waveform shaped by the upper side duty / phase control unit 4. Similarly, the lower lamp driving unit 7 drives the lower edge lamp 9 that is a light source of the liquid crystal display panel 3 based on the lower lamp driving waveform shaped by the lower duty / phase control unit 5.

  In this manner, the lamp control unit performs control to intermittently light the lamp by relating the video writing timing to the liquid crystal display panel 3 and the lamp lighting timing. In the present embodiment, the lamp controller turns off the upper edge lamp 8 and turns on the lower edge lamp 9 during the period in which the video of the written video signal is written in the upper liquid crystal display section 3a. In addition to the operation, the lamp control unit turns off the lower edge lamp 9 and turns on the upper edge lamp 8 during the period in which the video of the written video signal is written in the lower liquid crystal display unit 3b.

  The liquid crystal display device according to the present embodiment having such a configuration is not illuminated by a lamp on the edge of the liquid crystal display unit during a period in which an image is written on the liquid crystal display unit. For this reason, the image of the current frame is displayed in a state where the image of the previous frame does not remain as an afterimage in the retina of the eye. Thereby, the motion blur of a moving image can be reduced.

  FIG. 24 is a block diagram of a conventional liquid crystal display panel. The conventional liquid crystal display device requires a plurality of direct lamps 53 and a plurality of lamp driving units 52 for driving them as shown in FIG. In the liquid crystal display device according to the present embodiment, the thickness of the entire liquid crystal display device can be reduced by using the light guide plate 12 on the back surface of the liquid crystal display panel 3, and the above effect can be achieved with a small number of lamps. You can have it.

  Further, by disposing the lamps away from each other on the edge of the liquid crystal display panel 3, they can be prevented from warming each other due to their respective heat generation, so that an increase in the temperature around the lamps can be suppressed, and a decrease in luminance associated with the CCFL characteristics. Can be prevented.

  In addition, since the liquid crystal display unit on which no video is written is illuminated by the lamp, it is possible to suppress a reduction in brightness due to intermittent lighting of the lamp.

  In the present embodiment, the first lamp and the second lamp are arranged in the vertical direction so as to correspond to the video writing direction from top to bottom. However, the present invention is not limited to this, and when the writing direction is different, the same effect can be obtained even if the lamps are arranged, for example, in the left-right direction according to the writing direction.

<Embodiment 2>
A liquid crystal display device according to this embodiment will be described with reference to FIGS. In addition, about the structure which is not newly demonstrated below, it shall be the same as Embodiment 1. FIG.

  FIG. 4 is a timing chart schematically showing the relationship between the lamp driving waveform generated in the first embodiment and the lamp light emission waveform indicating the actual lighting state of the lamp. As shown in this figure, due to the light emission (afterglow) characteristics of the lamp, even if the lamp drive waveform is switched on or off, it is actually completely turned on or completely turned off. Takes time. For this reason, even if the lamp is turned off at the timing shown in FIG. 4, that is, the timing at which light emission (afterglow) characteristics are not taken into consideration, the effect of reducing the motion blur described in the first embodiment is reduced.

  Therefore, in the present embodiment, the lamp control unit starts turning off the lamp at a timing that is a predetermined time later than the timing at which the video is written on the liquid crystal display panel 3. This predetermined time is set in the upper-side duty / phase control unit 4 and the lower-side duty / phase control unit 5. The predetermined time is set to the delay time due to the afterglow characteristics of the lamps in both the upper-side duty / phase control unit 4 and the lower-side duty / phase control unit 5. FIG. 5 is a timing chart schematically showing the relationship between the lamp driving waveform generated by the lamp controller configured as described above and the actual lamp emission waveform.

  The liquid crystal display device according to the present embodiment configured as described above does not want to turn on the lamp, but can turn off the lamp during the period of lighting due to the afterglow characteristics. As a result, it is possible to realize motion blur reduction more effectively than in the first embodiment.

  The present invention may be applied to either the upper edge lamp 8 or the lower edge lamp 9, but is preferably applied to both edge lamps as in the present embodiment. Further, as the predetermined time, a period shorter than the period in which the afterglow characteristic of each edge lamp appears may be used, but the period in which the afterglow characteristic of each edge lamp appears is used as much as possible as in the present embodiment. It is desirable to do so.

<Embodiment 3>
A liquid crystal display device according to this embodiment will be described with reference to FIG. In addition, about the structure which is not newly demonstrated below, it shall be the same as Embodiment 1, and shall attach | subject the same code | symbol to the same part. In the second embodiment, the lamp is turned off retroactively for a predetermined time, but the lamp afterglow characteristic becomes longer as the light intensity of the lamp increases. Therefore, in this embodiment, the time point at which the lamp is turned off is changed in accordance with the intensity of the lamp light.

  FIG. 6 is a block diagram of the liquid crystal display device according to the present embodiment. FIG. 6 includes, in addition to FIG. 1, an upper side light detection unit 10 and a lower side light detection unit 11 which are light detection units that detect the intensity of light emitted from the lamp. In the present embodiment, the upper side light detection unit 10 and the lower side light detection unit 11 detect the intensity of light by the amount of light. The upper side light detection unit 10 and the lower side light detection unit 11 are, for example, optical sensors, and change the output voltage or the magnitude of the current according to the amount of light to be detected, and the digital output data is changed. Output.

  The upper-side light detection unit 10 detects the amount of light emitted from the upper-side edge lamp 8, and sends information corresponding to the amount of light to the upper-side duty / phase control via an upper-side light detection data processing unit (not shown). Output to part 4. The lower-side light detection unit 11 detects the amount of light emitted by the lower-side edge lamp 9, and sends information corresponding to the amount of light to the lower-side duty / phase control via a lower-side light detection data processing unit (not shown). Output to unit 5.

  The upper-side duty / phase control unit 4 generates an upper-side lamp driving waveform that changes the point in time when the upper-side edge lamp 8 starts to be turned off according to the amount of light detected by the upper-side light detection unit 10. . Similarly, the lower-side duty / phase control unit 5 changes the lower-side lamp drive waveform so as to change the time point at which the lower-side edge lamp 9 starts to be turned off according to the amount of light detected by the lower-side light detection unit 11. Is generated. In order to change the start time, for example, data relating to the delay time of the afterglow characteristic corresponding to the amount of light is stored in advance and the data is changed based on the data.

  Thus, the lamp control unit changes the timing at which the upper side edge lamp 8 starts to be turned off according to the intensity of light detected by the upper side light detection unit 10. Similarly, the lamp control unit changes the timing at which the lower edge lamp 9 starts to be turned off according to the intensity of light detected by the lower light detection unit 11.

  The liquid crystal display device according to the present embodiment configured as described above does not want to turn on the lamp, but can turn off the lamp more reliably than in the second embodiment during the period when the lamp is lit due to the afterglow characteristics. it can. As a result, the motion blur can be reduced more effectively than in the second embodiment.

<Embodiment 4>
A liquid crystal display device according to this embodiment will be described with reference to FIG. FIG. 7 is a schematic diagram of the light guide plate 12 in the liquid crystal display device according to the present embodiment. Here, in FIG. 7A, FIG. 7B, and FIG. An example is shown. FIG. 7 (a) is a generalized view of FIG. 7 (b).

  7 (a) -1, FIG. 7 (b) -1, and FIG. 7 (c) -1 are views seen from the liquid crystal display panel 3, and FIG. 7 (a) -2 and FIG. b) -2 and FIG.7 (c) -2 are the figures seen from the horizontal direction. Here, FIG. 7 (a) -1, FIG. 7 (b) -1, and FIG. 7 (c) -1 are views in which the liquid crystal display panel 3 is removed, unlike FIG. Appears. 7 (a) -3, FIG. 7 (b) -3, and FIG. 7 (c) -3 are diagrams showing the light transmittance of each light guide plate 12 in the vertical direction.

  As shown in FIG. 7A-1, the edge light type backlight system has the light guide plate 12 disposed on the back surface of the liquid crystal display panel 3 as in the first embodiment, and the lamp is located on the upper side of the liquid crystal display panel 3. The two edges, the edge and the lower edge, are arranged adjacent to the light guide plate 12. In FIG. 7 (b) -1 and FIG. 7 (c) -1, the lamp is omitted for simplicity.

  As shown in FIGS. 7 (a) -1, 7 (b) -1, and 7 (c) -1, the light guide plate 12 includes an upper liquid crystal display unit 3a and a lower liquid crystal display unit 3b, respectively. The upper side light transmission region 12a which is a first light transmission region corresponding to the above and the lower side light transmission region 12b which is a second light transmission region.

  The light guide plate 12 shown in FIGS. 7A and 7B has an upper light transmission region 12a and a lower light transmission region, as shown in FIGS. 7A-3 and 7B-3. The light transmission characteristics at the boundary with 12b are lower than the light transmission characteristics in other regions. In the present embodiment, this boundary is a virtual center line that divides the light guide plate 12 in the vertical direction. As the light guide plate 12 shown in FIG. 7A-1 approaches the center line from the end portion, the light transmittance decreases. In order to have such characteristics, for example, as shown in FIG. 7B-2, the thickness of the light guide plate 12 may be made thinner from the end toward the center. In the light guide plate 12 having such light transmittance, the movement of light from one region of the upper side light transmission region 12a and the lower side light transmission region 12b to the other region through the center line is blocked. .

  The light guide plate 12 shown in FIG. 7C is divided at the boundary between the upper side light transmission region 12a and the lower side light transmission region 12b, as shown in FIG. 7C-2. Again, the boundary is a virtual center line that divides the light guide plate 12 in the vertical direction. In such a light guide plate 12, the movement of light from one of the upper side light transmission region 12a and the lower side light transmission region 12b beyond the center line to the other region is blocked.

  If the light guide plate 12 having such characteristics is used, the light emitted from the lamp does not move beyond the center line that is the boundary between the upper side light transmission region 12a and the lower side light transmission region 12b. For this reason, even if the upper side edge lamp 8 is lit, the lower side liquid crystal display unit 3b is not illuminated due to the lighting. Similarly, even when the lower edge lamp 9 is lit, the upper liquid crystal display unit 3a is not illuminated due to the lighting. Thus, in the liquid crystal display device according to the present embodiment, the area to be turned off of the liquid crystal display unit is more surely turned off than in the first embodiment, so that motion blur can be reduced more effectively than in the first embodiment. Can be realized.

  In the light guide plate 12 as described above, since the in-plane distribution of the light emission amount to the liquid crystal display panel 3 varies, a compensation film may be provided between the light guide plate 12 and the liquid crystal display panel 3. . Thus, as shown in FIGS. 7A-4, 7B-4, and 7C-4, the liquid display device according to the present embodiment emits light uniformly over the entire surface. The liquid crystal display panel 3 can be irradiated in an amount.

<Embodiment 5>
Next, the liquid crystal display device according to this embodiment will be described with reference to FIGS. FIG. 8 is a block diagram showing the configuration of the liquid crystal display device according to this embodiment. In addition, about the structure which is not newly demonstrated below, it shall be the same as Embodiment 1, and shall attach | subject the same code | symbol to the same part. FIG. 9 is a timing chart of the panel vertical synchronizing signal, the writing video signal, the upper side lamp driving waveform, and the lower side lamp driving waveform.

  In the present embodiment, as shown in FIG. 8, instead of the upper duty / phase control unit 4 and the lower duty / phase control unit 5 used in the first embodiment, one duty / phase control unit 4a is provided. In use, both the upper edge lamp 8 and the lower edge lamp 9 are controlled. According to such a configuration, as shown in FIG. 9, the upper side lamp driving waveform and the lower side lamp driving waveform can be controlled with the same duty and the same phase, that is, with a phase difference of 0. The lower edge lamp 9 can be intermittently lit with a phase difference of zero.

  FIG. 10 is a block diagram showing a configuration in which the image motion detection unit 13 is added to the liquid crystal display device in the configuration of FIG. This video motion detector 13 is, for example, inside the video signal processing circuit, compares the video information of the current frame with the video information of one or more previous frames, and determines which of the video information of the entire frame. Detect if there is movement in the part. From this detection, the video motion detection unit 13 detects a region where the video displayed on the liquid crystal display unit of the liquid crystal display panel 3 moves. Then, the video motion detection unit 13 outputs information about the region to the duty / phase control unit 4a.

  FIG. 11 is a timing chart when the video motion detector 13 is added to the liquid crystal display device of FIG. The duty / phase control unit 4a shapes the PWM signal generated by the signal processing unit 1 with an arbitrary duty and phase. In the present embodiment, as shown in FIG. 11, the duty / phase control unit 4 a has an upper side lamp driving waveform that turns off the lamp during a period in which an image is written in an area detected by the image motion detection unit 13. A lower lamp driving waveform is generated. Under this condition, when the image displayed on the liquid crystal display unit continues to move in the entire area of the liquid crystal display unit, it is not turned on at all. Therefore, as shown in FIG. An upper side lamp driving waveform and a lower side lamp driving waveform for lighting the lamp are generated.

  The duty / phase control unit 4 a outputs such an upper lamp driving waveform to the upper lamp driving unit 6. Further, the duty / phase control unit 4 a outputs a lower lamp driving waveform that is the same as the upper lamp driving waveform to the lower lamp driving unit 7. In this way, the lamp control unit turns off the lamp during a period in which the video is written in the area detected by the video motion detection unit 13.

  In the liquid crystal display device according to the present embodiment configured as described above, the lamp is turned off during a period in which video is written in an area where there is video motion in the liquid crystal display unit. For this reason, the image of the current frame is displayed in a state where the region where the image displayed on the liquid crystal display unit is moving does not remain as an afterimage in the retina of the eye. Thereby, the motion blur of a moving image can be reduced. On the other hand, in the period in which the image is written in the region where there is no image movement in the liquid crystal display unit, the lamp is kept on without being turned off, so that the reduction in brightness seen in the entire liquid crystal display panel 3 can be suppressed.

  FIG. 12 is a block diagram showing a configuration in which a user specific area selection instruction unit 23 is added in place of the video motion detection unit 13 in the liquid crystal display device of FIG. The user specific area selection instructing unit 23 receives information related to a specific area instructed by external input information, for example, a lowermost area of a video in which a character telop appears in an adjustment unit in an OSD (on-screen display). This external input information is input by a user, for example. Then, the user specific area selection instruction unit 23 outputs the information to the duty / phase control unit 4a.

  In the video display unit, the duty / phase control unit 4a generates an upper side lamp driving waveform and a lower side lamp driving waveform that turn off the lamp during a period in which the video is written in the specific area specified by the external input information. . The duty / phase control unit 4a outputs such an upper lamp driving waveform and a lower lamp driving waveform to the upper lamp driving unit 6 and the lower lamp driving unit 7, respectively. In this way, the lamp control unit turns off the lamp during a period in which an image is written in the specific area designated by the external input information in the liquid crystal display unit.

  The liquid crystal display device according to the present embodiment configured as described above reduces motion blur of the moving image in the specific area designated by the external input information in the same manner as the area detected by the video motion detecting unit 13. Can be made. Further, since only a part of the liquid crystal display unit is intermittently lit, it is possible to suppress a reduction in brightness as seen in the entire liquid crystal display panel 3.

<Embodiment 6>
A liquid crystal display device according to this embodiment will be described with reference to FIGS. In addition, about the structure which is not newly demonstrated below, it shall be the same as Embodiment 1, and shall attach | subject the same code | symbol to the same part.

  When the upper side edge lamp 8 and the lower side edge lamp 9 are intermittently lit, the extinction period during which either the upper side edge lamp 8 or the lower side edge lamp 9 is not lit is the entire liquid crystal display panel 3. When viewed, the brightness decreases. Therefore, in this embodiment, a liquid crystal display device that reduces such a decrease in luminance will be described.

  FIG. 13A shows the same timing chart as in Embodiment 1, and FIG. 13B shows a timing chart of signals to be changed in the liquid crystal display device in this embodiment. It is. As shown in FIG. 13A, in the first embodiment, the video is written using the entire panel vertical synchronization period, but it is not necessary, and the video may be written in a period shorter than that period. Therefore, in the liquid crystal display device according to the present embodiment, the writing speed of the writing video signal is increased. That is, the length of the period during which video is written on the liquid crystal display panel 3 is shorter than one vertical synchronization period. Here, one vertical synchronization period is the period of the panel vertical synchronization signal.

  FIG. 13B shows a write video signal when the speed is twice the speed of the first embodiment (FIG. 13A), and the length of the period during which the video is written is It is ½ times during the synchronization of Form 1.

  The upper-side duty / phase control unit 4 turns the upper-side edge lamp 8 on during a period other than the period during which video is written in the upper-side liquid crystal display unit 3a, as shown in the upper-side lamp driving waveform of FIG. An upper lamp driving waveform that is lit is generated. The lower-side duty / phase control unit 5 turns off the lower-side edge lamp 9 during a period other than the period during which an image is written to the lower-side liquid crystal display unit 3b, as shown in the lower-side lamp drive waveform of FIG. An upper lamp driving waveform that is lit is generated. In this way, the lamp control unit performs control to turn on the lamp during a period different from the period during which video is written on the liquid crystal display panel 3.

  In the liquid crystal display device according to the present embodiment configured as described above, the period during which video is written is shortened. Therefore, the upper liquid crystal display unit 3a and the lower liquid crystal display unit 3b are respectively included in one vertical synchronization period. A period other than the period in which the video is written (blanking period) becomes longer. Then, the blanking period, which is shortened by increasing the period during which video is written on the liquid crystal display unit, is used as the lamp lighting period. For this reason, since the lamp turn-off period is short and the lamp turn-on time is long, it is possible to reduce a decrease in luminance as seen in the entire liquid crystal display panel 3.

<Embodiment 7>
A liquid crystal display device according to this embodiment will be described with reference to FIGS. In addition, about the structure which is not newly demonstrated below, it shall be the same as Embodiment 1, and shall attach | subject the same code | symbol to the same part.

  When the lamp is intermittently lit as in the first embodiment, color blur may occur at the edge portion of a moving image. FIG. 14 is a diagram showing the color blur, and it is assumed that the boundary portion between the white portion and the black portion in the reduced view is moving. The enlarged view is an enlarged view of a square portion written near the boundary of the reduced view. Although the cause of this color blur is unknown, there may be a difference in the R, G, B emission (afterglow) characteristics of the phosphor of the edge lamp, a difference in the R, G, B characteristics of the color filter, or the like. . In this embodiment, a liquid crystal display device that suppresses such color bleeding is described.

  FIG. 15 is a block diagram illustrating a configuration of the liquid crystal display device according to the present embodiment. As shown in the figure, an overdrive processing unit 14 and overdrive control data 15 are added to the configuration of the first embodiment.

  The overdrive processing unit 14 is a part that performs overdrive processing, and performs overdrive processing on each of the R, G, and B colors of the image on the liquid crystal display unit. Overdrive processing is a generally known technique that improves the response speed of intermediate gray levels by instantaneously applying a voltage that gives a larger gray level change than the original gray level change of the video signal to the liquid crystal. . The overdrive processing unit 14 controls the amount of overdrive for each color independently based on the overdrive control data for each of R, G, and B in the overdrive control data 15. The overdrive amount corresponds to the voltage described above, and the overdrive control data for each of the R, G, and B colors is composed of a plurality of overdrive amount data.

  In the liquid crystal display device configured as described above, the response speed of the intermediate gradation in each of the R, G, and B colors is improved by the functions of the overdrive processing unit 14 and the overdrive control data 15, as shown in FIG. 14 after the improvement. In addition, the light emission (afterglow) characteristics of each color can be suppressed. As a result, in the liquid crystal display unit, it is possible to suppress the color blur that has occurred at the edge portion of the moving image.

  FIG. 16 is a block diagram showing a configuration in which the video motion detection unit 13 is added to the liquid crystal display device of FIG. This video motion detector 13 is, for example, inside the video signal processing circuit, compares the video information of the current frame with the video information of one or more previous frames, and determines which of the video information of the entire frame. Detect how much the part is moving. From this detection, the video motion detection unit 13 detects a region where the video displayed on the liquid crystal display unit of the liquid crystal display panel 3 moves. The video motion detection unit 13 is connected to the overdrive processing unit 14 and outputs a detection result to the overdrive processing unit 14.

  Based on this result, the overdrive processing unit 14 selects the optimum R, G, B color overdrive control data 15 adapted to the video motion amount according to the motion amount of the region where the video motion is present. Thus, the color blur at the edge portion of the moving image is optimally suppressed.

  According to the liquid crystal display device configured as described above, it is possible to suppress the color blur that has occurred at the edge portion of the moving image as described above.

  FIG. 17 is a block diagram showing another configuration of the liquid crystal display device according to the present embodiment. As shown in the figure, in the block diagram of FIG. 15, a video edge correction processing unit 16 is provided instead of the overdrive processing unit 14, and an edge correction control data 17 is provided instead of the overdrive control data 15.

  The video edge correction processing unit 16 is a part that performs video edge correction processing, and performs video edge correction processing for each of the R, G, and B colors of the video on the liquid crystal display unit. In the present embodiment, this video edge correction process is a sharpness process, and increases the gradation change near the boundary between adjacent regions. The video edge correction processing unit 16 independently controls the sharpness amount of each color based on the edge correction control data of each color of R, G, B of the edge correction control data 17.

  In the liquid crystal display device configured as described above, the edges of the R, G, and B colors are corrected so as to be aligned by the functions of the video edge correction processing unit 16 and the edge correction control data 17. As a result, in the liquid crystal display unit, it is possible to suppress the color blur that has occurred at the edge portion of the moving image.

  FIG. 18 is a block diagram showing a configuration in which the video motion detection unit 13 is added to the liquid crystal display device of FIG. This video motion detection unit 13 is the same as the video motion detection unit 13 of FIG. 16 shown in the present embodiment. The video motion detection unit 13 is connected to the video edge correction processing unit 16 and outputs a detection result to the video edge correction processing unit 16. Then, the video edge correction processing unit 16 performs sharpness processing, which is video edge correction processing, in the same manner as the overdrive processing, according to the result detected by the video motion detection unit 13.

  According to the liquid crystal display device configured as described above, it is possible to suppress the color blur that has occurred at the edge portion of the moving image as described above.

<Eighth embodiment>
A liquid crystal display device according to this embodiment will be described with reference to FIGS. In addition, about the structure which is not newly demonstrated below, it shall be the same as Embodiment 1, and shall attach | subject the same code | symbol to the same part.

  As described in the sixth embodiment, when the upper side edge lamp 8 and the lower side edge lamp 9 are intermittently turned on, either the upper side edge lamp 8 or the lower side edge lamp 9 is not turned on. When the entire liquid crystal display panel 3 is viewed, the luminance is lowered. In order to prevent this, in the sixth embodiment, the period in which the video is written is shortened and the lamp is lit in the blanking period that is increased accordingly, but in this embodiment, the current flowing through the lamp is large. By changing the height, the luminance reduction is reduced.

  FIG. 19 is a block diagram showing a configuration of the liquid crystal display device according to the present embodiment. As shown in the figure, in the configuration of the first embodiment, the upper-side current control unit 18 connected to the upper-side duty / phase control unit 4 and the lower-side current control connected to the lower-side duty / phase control unit 5. Part 19 has been added.

  The upper-side current control unit 18 reads a period during which the upper-side edge lamp 8 is turned off from the upper-side lamp drive waveform generated by the upper-side duty / phase control unit 4. In this way, the upper side current control unit 18 which is a current control unit changes the current value supplied to the upper side edge lamp 8 in accordance with the period during which the lamp control unit turns off the upper side edge lamp 8. Here, the upper-side current control unit 18 works on the upper-side lamp driving unit 6 so as to increase the current value supplied to the upper-side edge lamp 8 as the period during which the upper-side edge lamp 8 is turned off becomes longer. .

  The lower-side current control unit 19 reads a period during which the lower-side edge lamp 9 is turned off from the lower-side lamp drive waveform generated by the lower-side duty / phase control unit 5. Thus, the lower-side current control unit 19 serving as a current control unit changes the current value supplied to the lower-side edge lamp 9 according to the period during which the lamp control unit turns off the lower-side edge lamp 9. Here, the lower-side current control unit 19 works on the lower-side lamp driving unit 7 to increase the current value supplied to the lower-side edge lamp 9 as the period during which the lower-side edge lamp 9 is turned off becomes longer.

  According to the liquid crystal display device configured as described above, the current flowing through the edge lamp increases and the brightness increases so as to correct the decrease in brightness due to the intermittent lighting of the edge lamp. The reduction in brightness is reduced.

  Next, another example of changing the lamp current value will be described with reference to FIG. In FIG. 20, a content information determination unit 20 is further added to the configuration of FIG. The content information determination unit 20 determines the content information of the video displayed on the liquid crystal display panel 3 and outputs the content information.

  The upper side current control unit 18 that is a current control unit changes the current value supplied to the upper side edge lamp 8 according to the content information determined by the content information determination unit 20. For example, when the video of the content is greatly affected by turning off, the current value is increased to reduce the influence.

  Similarly, the lower-side current control unit 19 that is a current control unit changes the current value supplied to the lower-side edge lamp 9 in accordance with the content information determined by the content information determination unit 20. For example, when the video of the content is greatly affected by turning off, the current value is increased to reduce the influence.

  According to the liquid crystal display device configured as described above, it is possible to appropriately correct a decrease in luminance when viewed in the entire liquid crystal display panel 3 in accordance with the type of input content.

<Embodiment 9>
A liquid crystal display device according to this embodiment will be described with reference to FIGS. In addition, about the structure which is not newly demonstrated below, it shall be the same as Embodiment 1, and shall attach | subject the same code | symbol to the same part. In the present embodiment, as in the eighth embodiment, a reduction in luminance when viewed from the entire liquid crystal display panel 3 is reduced.

  FIG. 21 is a block diagram showing a configuration of the liquid crystal display device according to the present embodiment. As shown in the figure, an upper lamp switching circuit 21 is provided instead of the upper current controller 18 and a lower lamp switching circuit 22 is provided instead of the lower current controller 19 with respect to the configuration of the eighth embodiment. .

  In the present embodiment, as shown in FIG. 23, a plurality of upper side edge lamps 8 are arranged at the upper edge of the liquid crystal display panel 3, and a plurality of lower side edge lamps 9 are arranged at the lower edge of the liquid crystal display panel 3. Is done. In this figure, three lamps are arranged on each of the upper side and the lower side.

  The upper lamp switching circuit 21 reads a period during which the upper edge lamp 8 is turned off from the upper lamp drive waveform generated by the upper duty / phase control unit 4. Thus, the upper lamp switching circuit 21 that is a lamp switching circuit changes the number of the upper edge lamps 8 to be turned on according to the period during which the lamp control unit turns off the upper edge lamp 8. Here, the upper-side lamp switching circuit 21 works on the upper-side lamp driving unit 6 so as to increase the number of the upper-side edge lamps 8 that are turned on as the period during which the upper-side edge lamp 8 is turned off becomes longer.

  The lower lamp switching circuit 22 reads a period during which the lower edge lamp 9 is turned off from the lower lamp driving waveform generated by the lower duty / phase control unit 5. Thus, the lower lamp switching circuit 22 that is a lamp switching circuit changes the number of lower edge lamps 9 to be turned on according to the period during which the lamp control unit turns off the lower edge lamp 9. Here, the lower-side lamp switching circuit 22 works on the lower-side lamp driving unit 7 so as to increase the number of lower-side edge lamps 9 that are turned on as the period during which the lower-side edge lamp 9 is turned off becomes longer.

  According to the liquid crystal display device configured as described above, the number of lamps to be lit is increased so as to correct the luminance decrease due to the intermittent lighting of the edge lamps, and the luminance decrease when viewed as a whole of the liquid crystal display panel 3 is reduced. The If the number of lamps is increased too much, the temperature around the lamp tends to increase. Therefore, it is desirable to determine the number of lamps in consideration of this temperature increase.

  Next, another example of changing the number of lamps to be lit will be described with reference to FIG. In FIG. 22, a content information determination unit 20 is further added to the configuration of FIG. The content information determination unit 20 determines the content information of the video displayed on the liquid crystal display panel 3 and outputs the content information.

  The upper lamp switching circuit 21 that is a lamp switching circuit changes the number of the upper edge lamps 8 to be lit according to the content information determined by the content information determination unit 20. For example, when the video of the content is greatly affected by turning off, the number of the upper side edge lamps 8 that are turned on is increased to reduce the influence.

  Similarly, the lower lamp switching circuit 22 which is a lamp switching circuit changes the number of lower edge lamps 9 to be lit according to the content information determined by the content information determination unit 20. For example, when the video of the content is greatly affected by turning off, the number of the upper side edge lamps 8 that are turned on is increased to reduce the influence.

  According to the liquid crystal display device configured as described above, it is possible to appropriately correct a decrease in luminance when viewed in the entire liquid crystal display panel 3 in accordance with the type of input content.

1 is a block diagram showing a configuration of a video display device according to Embodiment 1. FIG. FIG. 3 is a timing diagram illustrating intermittent lighting of the video display device according to the first embodiment. 1 is a diagram illustrating a configuration of a video display device according to Embodiment 1. FIG. FIG. 10 is a timing diagram illustrating intermittent lighting of the video display device according to the second embodiment. FIG. 10 is a timing diagram illustrating intermittent lighting of the video display device according to the second embodiment. 6 is a block diagram illustrating a configuration of a video display device according to Embodiment 3. FIG. It is a figure explaining the light-guide plate of the video display apparatus concerning Embodiment 4. FIG. FIG. 10 is a block diagram illustrating a configuration of a video display device according to a fifth embodiment. FIG. 10 is a timing diagram illustrating intermittent lighting of the video display device according to the fifth embodiment. FIG. 10 is a block diagram illustrating a configuration of a video display device according to a fifth embodiment. FIG. 10 is a timing diagram illustrating intermittent lighting of the video display device according to the fifth embodiment. FIG. 10 is a block diagram illustrating a configuration of a video display device according to a fifth embodiment. FIG. 10 is a timing diagram illustrating intermittent lighting of the video display device according to the sixth embodiment. FIG. 10 is a diagram illustrating a problem of a video display device according to a seventh embodiment. FIG. 10 is a block diagram illustrating a configuration of a video display device according to a seventh embodiment. FIG. 10 is a block diagram illustrating a configuration of a video display device according to a seventh embodiment. FIG. 10 is a block diagram illustrating a configuration of a video display device according to a seventh embodiment. FIG. 10 is a block diagram illustrating a configuration of a video display device according to a seventh embodiment. FIG. 10 is a block diagram illustrating a configuration of a video display device according to an eighth embodiment. FIG. 10 is a block diagram illustrating a configuration of a video display device according to an eighth embodiment. FIG. 10 is a block diagram illustrating a configuration of a video display device according to Embodiment 9. FIG. 10 is a block diagram illustrating a configuration of a video display device according to Embodiment 9. FIG. 20 is a diagram for describing a configuration of a video display apparatus according to Embodiment 9; It is a block diagram which shows the structure of the conventional video display apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Signal processing part, 2 Signal output part, 3 Liquid crystal display panel, 3a Upper side liquid crystal display part, 3b Lower side liquid crystal display part, 4 Upper side duty / phase control part, 4a Duty / phase control part, 5 Lower side duty / Phase control unit, 6 Upper side lamp driving unit, 7 Lower side lamp driving unit, 8 Upper side edge lamp, 9 Lower side edge lamp, 10 Upper side light detection unit, 11 Lower side light detection unit, 12 Light guide plate, 12a Upper part Side light transmission region, 12b Lower side light transmission region, 13 Video motion detection unit, 14 Overdrive processing unit, 15 Overdrive control data, 16 Video edge correction processing unit, 17 Edge correction control data, 18 Upper side current control unit, 19 Lower-side current control unit, 20 Content information determination unit, 21 Upper-side lamp switching circuit, 22 Lower-side lamp switching circuit 23 User specific region selection instruction unit.

Claims (18)

A liquid crystal display panel;
A light guide plate disposed on the back surface of the liquid crystal display panel;
A lamp disposed adjacent to the light guide plate at two opposing edges of the liquid crystal display panel;
A lamp control unit that controls the intermittent lighting of the lamp in association with the video writing timing to the liquid crystal display panel and the lighting timing of the lamp;
Liquid crystal display device. The liquid crystal display panel is
Including first and second liquid crystal display parts obtained by dividing one liquid crystal display part,
The lamp is
A first lamp disposed on the first liquid crystal display unit side, and a second lamp disposed on the second liquid crystal display unit side,
The lamp control unit
During the period in which the video is written on the first liquid crystal display unit, the first lamp is turned off, the second lamp is turned on,
Turning off the second lamp and turning on the first lamp during a period in which the video is written to the second liquid crystal display unit;
The liquid crystal display device according to claim 1. The light guide plate is
Having first and second light transmission regions respectively corresponding to the first and second liquid crystal display units;
The light transmission characteristics at the boundary between the first light transmission area and the second light transmission area are lower than the light transmission characteristics of the other areas;
The liquid crystal display device according to claim 2. The light guide plate is
As the boundary is approached from the end, the light transmission characteristics become lower.
The liquid crystal display device according to claim 3. The light guide plate is
Having first and second light transmission regions respectively corresponding to the first and second liquid crystal display units;
It is divided at the boundary between the first light transmission region and the second light transmission region,
The liquid crystal display device according to claim 2. The lamp control unit
The lamp is turned off at a timing that is a predetermined time later than the timing at which the video is written on the liquid crystal display panel.
The liquid crystal display device according to claim 1. A light detector for detecting the intensity of light emitted by the lamp;
The lamp control unit
According to the intensity of light detected by the light detection unit, to change the timing to start turning off the lamp,
The liquid crystal display device according to claim 1. A video motion detection unit for detecting a region in which a video displayed on the liquid crystal display unit of the liquid crystal display panel moves;
The lamp control unit
The lamp is turned off during a period in which the video is written in the area detected by the video motion detector.
The liquid crystal display device according to claim 1. The lamp control unit
In the liquid crystal display portion of the liquid crystal display panel, the lamp is turned off during a period in which video is written in a specific area designated by external input information.
The liquid crystal display device according to claim 1. The length of the period during which video is written on the liquid crystal display panel is shorter than one vertical synchronization period,
The lamp control unit performs control to turn on the lamp in a period other than a period in which the video is written on the liquid crystal display panel in the one vertical synchronization period.
The liquid crystal display device according to claim 1. An overdrive processing unit that performs overdrive processing on each color of the video displayed on the liquid crystal display panel;
The liquid crystal display device according to claim 1. A video motion detection unit for detecting a region in which a video displayed on the liquid crystal display unit of the liquid crystal display panel moves;
The overdrive processing unit
According to the result detected by the video motion detection unit, overdrive processing is performed.
The liquid crystal display device according to claim 11. A video edge correction processing unit that performs video edge correction processing on each color of the video displayed on the liquid crystal display panel;
The liquid crystal display device according to claim 1. A video motion detection unit for detecting a region in which a video displayed on the liquid crystal display unit of the liquid crystal display panel moves;
The video edge correction processing unit
Depending on the result detected by the video motion detection unit, video edge correction processing is performed.
The liquid crystal display device according to claim 13. A current control unit that changes a current value supplied to the lamp according to a period during which the lamp control unit turns off the lamp;
The liquid crystal display device according to claim 1. A content information discriminating unit for discriminating content information of video displayed on the liquid crystal display panel;
A current control unit that changes a current value supplied to the lamp according to the content information determined by the content information determination unit;
The liquid crystal display device according to claim 1. A plurality of the lamps are arranged at each of the edges of the liquid crystal display panel,
A lamp switching circuit that changes the number of the lamps to be turned on according to a period during which the lamp control unit turns off the lamps;
The liquid crystal display device according to claim 1. A plurality of the lamps are arranged at each of the edges of the liquid crystal display panel,
A content information discriminating unit for discriminating content information of video displayed on the liquid crystal display panel;
A lamp switching circuit for changing the number of the lamps to be turned on according to the content information determined by the content information determination unit;
The liquid crystal display device according to claim 1.

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