JP2012252158A - Liquid crystal display device and liquid crystal television device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device and a liquid crystal television device, capable of providing high luminance stability and preventing electrostrictive vibration from a power supply transformer in a structure that adjusts the luminance of a backlight by blinking light sources.SOLUTION: A liquid crystal television device 100 (liquid crystal display device) comprises: a liquid crystal display panel 111 capable of displaying an image; a backlight 112 having five first LEDs 112a and five second LEDs 112b and illuminating the liquid crystal display panel 111 with light; a power source transformer 14 that transforms the voltage of a primary side into that of a secondary side to be applied to the backlight 111; and a control part 12 that controls the power (current) supplied to the first LEDs 112a and the second LEDs to alternately blink the first and second LEDs 112a and 112b.

Description

  The present invention relates to a liquid crystal display device and a liquid crystal television device, and more particularly to a liquid crystal display device and a liquid crystal television device that include a backlight.

  Conventionally, a liquid crystal display device including a backlight is known (for example, see Patent Document 1).

  In Patent Document 1, a liquid crystal panel (liquid crystal display panel) capable of displaying an image, a backlight including three light emitting elements (light sources) for irradiating light to the liquid crystal panel, and three light emitting elements are repeatedly blinked. A liquid crystal display device including a backlight control device (control unit) that performs control is disclosed. In this liquid crystal display device, the backlight control device turns off any one of the three light emitting elements and simultaneously turns on the other one so that the three light emitting elements blink in order. The light brightness is adjusted.

JP 2006-251533 A

  However, in the liquid crystal display device of Patent Document 1, the three light emitting elements are sequentially blinked so that one of the three light emitting elements (light sources) is turned off and the other one is turned on at the same time. As a result, the luminance of the backlight is adjusted, and it is difficult to precisely match the timing of turning off any one of the three light emitting elements with the timing of lighting one of the other light emitting elements. If the timing of turning off and the timing of turning on are slightly different, both will be turned off or turned on instantaneously, resulting in a luminance that is different from the designed luminance (only one of them is lit), so the luminance stability is low. There is a problem.

  Conventionally, in a configuration that includes a power transformer that converts voltage to supply power to the light source, when the load variation of the power transformer becomes large when the backlight light source blinks, the power transformer makes a sound. There is also a problem that it ends up.

  The present invention has been made to solve the above-described problems, and one object of the present invention is to obtain high luminance stability in a configuration in which the luminance of the backlight is adjusted by blinking the light source. It is possible to provide a liquid crystal display device and a liquid crystal television device that can suppress the sound of a power transformer.

Means for Solving the Problems and Effects of the Invention

  A liquid crystal display device according to a first aspect of the present invention includes a liquid crystal display panel capable of displaying an image, one first light source obtained by dividing a plurality of light sources into two, and the other second light source. The backlight to be irradiated, the power transformer for converting the primary side voltage to the secondary side voltage to be supplied to the backlight, and the power supplied to the first light source and the second light source are controlled and repeatedly flashing alternately. A control unit that controls the first light source and the second light source so that the timing of turning on and off the first light source and the timing of turning on and off the second light source do not overlap each other. It is configured to perform control to blink repeatedly.

  In the liquid crystal display device according to the first aspect, by turning on and off the first light source, the timing of turning on and off the first light source and the timing of turning off and turning on the second light source do not overlap each other. Even when the timing and the timing of turning off and turning on the second light source are slightly shifted, both the first light source and the second light source are not turned off instantaneously or both are turned on, contrary to the design. It is possible to suppress a luminance that is different from the luminance designed instantaneously. Thereby, stability with high luminance can be obtained. In addition, the timing of turning on and off the first light source and the timing of turning on and off the second light source do not overlap each other, thereby distributing the timing of load fluctuation of the power transformer accompanying the blinking of the light source once. Therefore, it is possible to reduce the load fluctuation that occurs in the power transformer. Thereby, high brightness stability can be obtained, and the power transformer can be prevented from making a sound. Also, there is provided a control unit for controlling the power supplied to one first light source obtained by dividing the plurality of light sources into two and the other second light source obtained by dividing the plurality of light sources into two so as to alternately and repeatedly flash. Thus, since the luminance can be adjusted only by the control unit controlling the two light sources, the control by the control unit can be simplified.

  In the liquid crystal display device according to the first aspect, preferably, the control unit causes the first light source and the second light source to blink at predetermined intervals, and the timing to turn on the first light source and the timing to turn on the second light source. Are controlled so as to deviate from each other by a predetermined time, so that the timing of turning on and off the first light source and the timing of turning on and off the second light source do not overlap each other. It is configured to blink alternately and repeatedly. If comprised in this way, the timing of lighting and extinguishing of a 1st light source and the timing of lighting and extinguishing of a 2nd light source can be made not to mutually overlap easily.

  In this case, preferably, the control unit alternately turns the first light source and the second light source so that the timing for turning on the first light source and the timing for turning on the second light source are shifted from each other by a half cycle of a predetermined cycle. It is configured to perform control to blink repeatedly. With this configuration, it is possible to ensure that the timing of turning on and off the first light source and the timing of turning on and off the second light source do not overlap each other.

  In the liquid crystal display device according to the first aspect, preferably, the control unit alternately switches the first light source and the second light source so that the frequency at which the first light source and the second light source blink is the frequency within the audible range of the sound. And the control is performed so that the frequency of the power change caused by blinking the first light source and the second light source becomes a frequency outside the audible range of the sound. If comprised in this way, even if a sound generate | occur | produces from a power transformer by the load fluctuation | variation of a power transformer, the sound generated from a power transformer can be prevented from being heard substantially.

  In the liquid crystal display device according to the first aspect, preferably, the first light source and the second light source each include a plurality of first light emitting elements and a plurality of second light emitting elements, and the control unit includes the plurality of first light emitting elements. Control that causes the plurality of first light-emitting elements and the plurality of second light-emitting elements to alternately flash repeatedly so that the timing of lighting and extinguishing of the light-emitting elements and the timing of lighting and extinguishing of the plurality of second light-emitting elements do not overlap each other. Configured to do. With such a configuration, a power change caused by blinking the first light source and the second light source can be further reduced by using a light emitting element that consumes less power than a cold cathode fluorescent lamp or the like. The load fluctuation of the transformer can be further reduced.

  A liquid crystal television apparatus according to a second aspect of the present invention includes a liquid crystal display panel capable of displaying an image, a tuner for receiving a television signal, one first light source obtained by dividing a plurality of light sources into two, and the other second. A backlight including a light source and irradiating the liquid crystal display panel with light; a power transformer for converting a primary side voltage to a secondary side voltage supplied to the backlight; and a first light source and a second light source. And a control unit that controls power to repeatedly and alternately blink so that the timing of turning on and off the first light source and the timing of turning on and off the second light source do not overlap each other. The first light source and the second light source are configured to perform control of repeatedly blinking alternately.

  In the liquid crystal television apparatus according to the second aspect, the first light source is turned on and off by preventing the timing of turning on and off the first light source and the timing of turning off and lighting the second light source from each other. Even if there is a slight difference between the timing of the second light source and the timing of turning off and turning on the second light source, both the first light source and the second light source will not be turned off or both turned on instantaneously, contrary to the design. Thus, it is possible to suppress the luminance from being different from the luminance designed instantaneously. Thereby, stability with high luminance can be obtained. In addition, the timing of turning on and off the first light source and the timing of turning on and off the second light source do not overlap each other, thereby distributing the timing of load fluctuation of the power transformer accompanying the blinking of the light source once. Therefore, it is possible to reduce the load fluctuation that occurs in the power transformer. Thereby, high brightness stability can be obtained, and the power transformer can be prevented from making a sound. Such an effect is particularly effective in a liquid crystal television device that is desired to be quiet. Also, there is provided a control unit for controlling the power supplied to one first light source obtained by dividing the plurality of light sources into two and the other second light source obtained by dividing the plurality of light sources into two so as to alternately and repeatedly flash. Thus, since the luminance can be adjusted only by the control unit controlling the two light sources, the control by the control unit can be simplified.

It is the block diagram which showed the structure of the liquid crystal television apparatus by 1st and 2nd embodiment of this invention. It is the block diagram which showed the structure of the backlight of the liquid crystal television apparatus by 1st and 2nd embodiment of this invention. It is the figure which showed the change of the electric current for blinking 1st LED of the liquid crystal television apparatus by 1st Embodiment of this invention. It is the figure which showed the change of the electric current for blinking 2nd LED of the liquid crystal television apparatus by 1st Embodiment of this invention. It is the figure which showed the change of the total electric current at the time of blinking 1st LED and 2nd LED of the liquid crystal television apparatus by 1st Embodiment of this invention. It is the figure which showed the change of the electric current for blinking 1st LED of the liquid crystal television apparatus by 2nd Embodiment of this invention. It is the figure which showed the change of the electric current for blinking 2nd LED of the liquid crystal television apparatus by 2nd Embodiment of this invention. It is the figure which showed the change of the total electric current at the time of blinking 1st LED and 2nd LED of the liquid crystal television apparatus by 2nd Embodiment of this invention. It is the block diagram which showed the structure of the backlight of the liquid crystal television apparatus by the modification of 1st and 2nd embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
First, the configuration of the liquid crystal television device 100 according to the first embodiment of the present invention will be described with reference to FIG. 1 and FIG. The liquid crystal television device 100 is an example of the “liquid crystal display device” in the present invention.

  As shown in FIG. 1, the liquid crystal television device 100 according to the first embodiment of the present invention includes a liquid crystal display unit 11, a control unit 12, a power source 13, a power transformer 14, a driver 15, a tuner 16, And a decoder 17.

  The liquid crystal display unit 11 includes a liquid crystal display panel 111 and a backlight 112. The liquid crystal display panel 111 is configured to be able to display an image processed by the decoder 17 based on a television signal received via the tuner 16.

  The backlight 112 is configured to irradiate light toward the liquid crystal display panel 111. Specifically, as shown in FIG. 2, the backlight 112 includes five first LEDs (light emitting diodes) 112a and five second LEDs 112b, and displays light output from the first LEDs 112a and the second LEDs 112b in a liquid crystal display. The panel 111 is configured to irradiate. Accordingly, the liquid crystal display panel 111 is configured to be able to display a bright and clear image. The first LED 112a is an example of the “first light source” and the “first light emitting element” in the present invention, and the second LED 112b is an example of the “second light source” and the “second light emitting element” in the present invention.

  The first LED 112 a and the second LED 112 b are each connected to the control unit 12 via the driver 15. Further, the first LED 112a and the second LED 112b are configured to be blinkable depending on the presence or absence of current supplied from the driver 15. The backlight 112 is configured such that the luminance can be adjusted by the ratio of the time during which the first LED 112a and the second LED 112b are turned on and the time when the first LED 112a is turned off. Specifically, the backlight 112 is configured such that the luminance increases when the proportion of the time during which the first LED 112a and the second LED 112b are lit increases, and the luminance decreases when the proportion of the lighting time decreases. Yes.

  The control unit 12 is configured to control each unit of the liquid crystal television device 100. The control unit 12 is configured to be supplied with power from the power supply 13 via the power transformer 14. Further, the control unit 12 is configured to control the current supplied to the first LED 112a and the second LED 112b via the driver 15 so as to cause the first LED 112a and the second LED 112b to blink.

  The power source 13 is arranged on the primary side and configured to be able to supply a voltage of 100 V supplied from the outside to the power transformer 14. The power transformer 14 is configured to be able to convert a 100V voltage output from the power supply 13 into a 5V voltage input to the control unit 12 disposed on the secondary side. The power transformer 14 is configured to operate in accordance with the power (current) output to the control unit 12. Specifically, when the current supplied to the backlight 112 via the control unit 12 and the driver 15 increases, the load on the power transformer 14 increases, and when the current supplied to the backlight 112 decreases, the load on the power transformer 14 increases. Is configured to be small. That is, the load variation of the power transformer 14 increases as the change in the current supplied to the backlight 112 increases.

  The driver 15 is configured to supply current to the first LED 112 a and the second LED 112 b of the backlight 112 under the control of the control unit 12. The tuner 16 is configured to be able to receive a television signal. The decoder 17 is configured to process the television signal received by the tuner 16 to obtain an image that can be displayed on the liquid crystal display panel 111.

  Next, with reference to FIGS. 3 to 5, a change in current when the first LED 112 a and the second LED 112 b of the backlight 112 of the liquid crystal television apparatus 100 are blinked will be described.

  As shown in FIG. 3, the first LED 112 a is controlled by the current supplied by the control unit 12. Specifically, the five first LEDs 112a are supplied with the current I during the time t1 to t4 and stopped during the time t4 to t5 at the time t1 to t5. In addition, the five first LEDs 112a are repeatedly supplied and stopped in the same manner with the time t1 to t5 as one cycle. Accordingly, the five first LEDs 112a are repeatedly turned on and off at a predetermined frequency (for example, 10 kHz within the audible range of the sound). Further, here, the duty ratio indicating the ratio of the time during which the first LED 112a is lit in one cycle is 3/4.

  As shown in FIG. 4, the second LED 112 b is controlled in current supplied by the control unit 12. The second LED 112b is supplied with a current so that the timing of turning on and off the second LED 112b does not overlap with the timing of turning on and off the first LED 112a. Specifically, at the time t3 to t7, the five second LEDs 112b are supplied with the current I during the time t3 to t6, and are stopped from supplying current during the time t6 to t7. The five second LEDs 112b are repeatedly supplied and stopped in the same manner with the period from time t3 to t7 as one cycle. As a result, the five second LEDs 112b are repeatedly turned on and off at the same predetermined frequency as the first LED 112a (for example, 10 kHz within the audible range of the sound) with a half-cycle shift from the first LED 112a. In addition, here, the duty ratio indicating the ratio of the time during which the second LED 112b is lit in one cycle is 3/4.

  Here, in the first embodiment, as shown in FIG. 5, current is supplied from the driver 15 to the backlight 112. Specifically, the backlight 112 is supplied with the total current of the current supplied to the first LED 112a and the current supplied to the second LED 112b. From time t1 to t2, the same current I is supplied to both the first LED 112a and the second LED 112b. From time t2 to t3, the current I is supplied only to the first LED 112a. Thereafter, the case where the current I is supplied to both the first LED 112a and the second LED 112b and the case where the current I is supplied to only one of them are repeated. That is, the change in the current supplied to the backlight 112 is repeated between the period in which the current 2I is supplied and the period in which the current I is supplied, with the time t1 to t3 as one cycle. Thereby, the change in the current supplied to the backlight 112 can be halved compared to the case where current is supplied (stopped) to both the first LED 112a and the second LED 112b simultaneously.

  Further, the frequency of change in power (current) supplied to the backlight 112 (for example, 20 kHz outside the sound audible range) is twice the frequency of blinking of the first LED 112a and the second LED 112b (for example, 10 kHz within the sound audible range). Become. Thereby, the control unit 12 causes the first LED 112a and the second LED 112b to blink at a frequency (for example, 10 kHz) within the audible range of the sound, and changes the power (current) supplied to the backlight to a frequency (for example, the frequency outside the audible range of the sound) , 20 kHz).

  In the first embodiment, as described above, the timing of turning on and off the first LED 112a and the timing of turning on and off the first LED 112a and the timing of turning off and lighting the second LED 112b do not overlap each other. Even when the timing of turning off and turning on the 2LEDs 112b is slightly shifted, both the first LED 112a and the second LED 112b are not turned off instantaneously or both are turned on contrary to the design. It can suppress that it becomes the brightness | luminance different from. Thereby, stability with high luminance can be obtained. In addition, the timing of turning on and off the first LED 112a and the timing of turning on and off the second LED 112b do not overlap each other, thereby distributing the timing of load fluctuation of the power transformer 14 caused by the blinking of the first LED 112a and the second LED 112b. As a result, it is possible to reduce the load fluctuation that occurs at one time, so that the power transformer 14 can be prevented from making a sound. Thereby, stability with high brightness | luminance can be obtained and it can suppress that the power transformer 14 makes a sound. Such an effect is particularly effective in the liquid crystal television device 100 in which silence is desired. Further, by providing a control unit 12 that controls the power supplied to one first LED 112a obtained by dividing the plurality of light sources into two and the other second LED 112b obtained by dividing the plurality of light sources into two parts, and performs control to alternately and repeatedly flash each. Since the brightness can be adjusted only by the control unit 12 controlling the two light sources, the control by the control unit 12 can be simplified.

  In the first embodiment, the control unit 12 causes the first LED 112a and the second LED 112b to blink at a predetermined cycle, and the timing for lighting the first LED 112a and the timing for lighting the second LED 112b are shifted from each other by a half cycle. In this configuration, the first LED 112a and the second LED 112b are alternately and repeatedly controlled to blink alternately, so that the timing of turning on and off the first LED 112a and the timing of turning on and off the second LED 112b are surely not overlapped with each other. be able to.

  In the first embodiment, the control unit 12 causes the first LED 112a and the second LED 112b to blink alternately and repeatedly so that the frequency for blinking the first LED 112a and the second LED 112b becomes a frequency within the audible range of sound (for example, 10 kHz). In addition, the load of the power transformer 14 is controlled by controlling the frequency of the power (current) change caused by blinking the first LED 112a and the second LED 112b to be a frequency outside the audible range of sound (for example, 20 kHz). Even if the sound is generated from the power transformer 14 due to the fluctuation, it is possible to substantially prevent the sound generated from the power transformer 14 due to the load fluctuation of the power transformer 14 from being heard.

  In the first embodiment, by providing five first LEDs 112a and five second LEDs 112b as light sources, by using LEDs that consume less power than a cold cathode fluorescent lamp or the like, the light source is caused to blink. Since the power change can be made smaller, the load fluctuation of the power transformer 14 can be made smaller.

(Second Embodiment)
Next, with reference to FIG. 1, FIG. 2, and FIGS. 6-8, the liquid crystal television apparatus 100 by 2nd Embodiment of this invention is demonstrated. In the second embodiment, unlike the first embodiment, a liquid crystal television apparatus 100 having a duty ratio of 1/2 indicating the proportion of time during which the first LED 112a and the second LED 112b are lit in one cycle will be described. .

  As shown in FIGS. 1 and 2, the liquid crystal television apparatus 100 according to the second embodiment has the same configuration as that of the first embodiment. The liquid crystal television device 100 is an example of the “liquid crystal display device” in the present invention.

  With reference to FIGS. 6-8, the change of the electric current at the time of blinking 1st LED112a and 2nd LED112b of the backlight 112 of the liquid crystal television apparatus 100 is demonstrated.

  Here, in the second embodiment, as shown in FIG. 6, the current supplied by the control unit 12 is controlled in the first LED 112a. Specifically, the five first LEDs 112a are supplied with the current I during the time t1 to t3 and stopped during the time t3 to t5 at the time t1 to t5. In addition, the five first LEDs 112a are repeatedly supplied and stopped in the same manner with the time t1 to t5 as one cycle. Thus, the five first LEDs 112a are repeatedly turned on and off at a predetermined frequency (for example, 100 Hz). Further, here, the duty ratio representing the ratio of the time during which the first LED 112a is lit in one cycle is ½.

  As shown in FIG. 7, the current supplied from the control unit 12 is controlled in the second LED 112b. The second LED 112b is supplied with a current so that the timing of turning on and off the second LED 112b does not overlap with the timing of turning on and off the first LED 112a. Specifically, at the time t2 to t6, the five second LEDs 112b are supplied with the current I during the time t2 to t4 and are stopped from supplying current during the time t4 to t6. The five second LEDs 112b are repeatedly supplied and stopped in the same manner with the period from time t2 to t6 as one cycle. As a result, the five second LEDs 112b are repeatedly turned on and off at a predetermined frequency (for example, 100 Hz) as the first LEDs 112a with a predetermined time shift from the first LED 112a (in this case, delayed by a quarter cycle). It is. Further, here, the duty ratio indicating the ratio of the time during which the second LED 112b is lit in one cycle is ½.

  As shown in FIG. 8, current is supplied to the backlight 112 from the driver 15. Specifically, the backlight 112 is supplied with the total current of the current supplied to the first LED 112a and the current supplied to the second LED 112b. Specifically, in the backlight 112, the same current I is supplied to both the first LED 112a and the second LED 112b at the time t2 to t3 at the time t2 to t6, and the current I is supplied only to the second LED 112b at the time t3 to t4. The current is supplied to both the first LED 112a and the second LED 112b from time t4 to t5, and the current I is supplied only to the first LED 112a from time t5 to t6. The change in current supplied to the backlight 112 is repeated in the same manner with the period from time t2 to t6 as one cycle. Thereby, the instantaneous change of the current supplied to the backlight 112 can be halved compared to the case where the current is supplied (stopped) to both the first LED 112a and the second LED 112b simultaneously. Moreover, the frequency (for example, 100 Hz) of the electric power (current) supplied to the backlight 112 is equal to the blinking frequency (for example, 100 Hz) of the first LED 112a and the second LED 112b.

  In addition, the other structure of 2nd Embodiment is the same as that of the said 1st Embodiment.

  As described above, also in the configuration of the second embodiment, as in the first embodiment, the timing of turning on and off the first LED 112a and the timing of turning on and off the second LED 112b do not overlap each other. Therefore, it is possible to obtain a high luminance stability and to suppress the sound of the power transformer 14.

  Further, in the second embodiment, as described above, the control unit 12 causes the first LED 112a and the second LED 112b to blink at predetermined intervals, and the timing for lighting the first LED 112a and the timing for lighting the second LED 112b are predetermined. The first LED 112a and the second LED 112b are alternately and repeatedly flashed so that the timing of lighting and extinguishing of the first LED 112a and the timing of lighting and extinguishing of the second LED 112b do not overlap each other by controlling so as to be shifted from each other by time. By doing so, it is possible to easily prevent the timing of lighting and extinguishing of the first LED 112a from timing of lighting and extinguishing of the second LED 112b.

  The remaining effects of the second embodiment are similar to those of the aforementioned first embodiment.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the first and second embodiments, the example in which the liquid crystal television device is applied as an example of the liquid crystal display device of the present invention is shown, but the present invention is not limited to this. The present invention may be applied to a liquid crystal display device other than the liquid crystal television device. For example, the liquid crystal display device of the present invention may be applied to a liquid crystal display for a personal computer (PC), a liquid crystal monitor mounted in a car navigation system, or the like.

  Moreover, in the said 1st Embodiment, the duty ratio showing the ratio of the time which 1st LED as a 1st light source and 2nd LED as a 2nd light source are lit among 1 period is shown to 3/4, In the second embodiment, an example in which the duty ratio is 1/2 has been described. However, the present invention is not limited to this. In the present invention, the duty ratio may be other than 3/4 and 1/2.

  In the first embodiment, the example in which the first LED as the first light source and the second LED as the second light source are blinked at a predetermined frequency (for example, 10 kHz) is shown, but the present invention is not limited to this. . In the present invention, the first light source and the second light source may blink at a frequency other than 10 kHz.

  In the second embodiment, the example in which the first LED as the first light source and the second LED as the second light source are blinked at a predetermined frequency (for example, 100 Hz) is shown, but the present invention is not limited to this. . In the present invention, the first light source and the second light source may be blinked at a frequency other than 100 Hz.

  Moreover, in the said 1st Embodiment, the frequency of the electric power change by blinking the 1st LED as a 1st light source and the 2nd LED as a 2nd light source turns into a frequency (for example, 20 kHz) outside a sound audible range is shown. However, the present invention is not limited to this. In the present invention, the frequency of the power change caused by blinking the first light source and the second light source may be a frequency outside the audible range other than 20 kHz.

  In the first embodiment, the timing at which the first LED as the first light source is turned on and the timing at which the second LED as the second light source is turned on are only a half cycle of the period when the first light source and the second light source flash. Although the example which has shifted | deviated mutually was shown, this invention is not limited to this. In the present invention, if the timing of turning on and off the first light source and the timing of turning on and off the second light source do not overlap with each other, the timing for turning on the first light source and the timing for turning on the second light source are the first. The light source and the second light source may be shifted from each other by a predetermined time other than the half cycle of the cycle in which the light source and the second light source flash.

  In the second embodiment, the timing at which the first LED as the first light source is turned on and the timing at which the second LED as the second light source is turned on are ¼ cycles of the cycle at which the first light source and the second light source flash. Although the example which shifted | deviated from each other was shown, this invention is not limited to this. In the present invention, if the timing of turning on and off the first light source and the timing of turning on and off the second light source do not overlap with each other, the timing for turning on the first light source and the timing for turning on the second light source are the first. The light source and the second light source may be shifted from each other by a predetermined time other than a quarter cycle of the cycle of blinking. However, when the duty ratio is 1/2 as in the second embodiment, in order to prevent the timing of turning on and off the first light source and the timing of turning on and off the second light source from overlapping each other, It is necessary to make the timing for turning on one light source and the timing for turning on the second light source deviate from each other by a predetermined time other than a half cycle of the cycle in which the first light source and the second light source blink.

  Moreover, in the said embodiment, although the example of a structure which uses LED as a 1st light source and a 2nd light source was shown, this invention is not limited to this. In this invention, the structure which uses light sources other than LED as a 1st light source and a 2nd light source, respectively may be sufficient. For example, as shown in FIG. 9, a CCFL (cold cathode fluorescent lamp) or the like may be used as the light source as the first light source and the second light source, respectively.

12 Control Unit 14 Power Transformer 16 Tuner 100 Liquid Crystal Television Device (Liquid Crystal Display Device)
111 Liquid crystal display panel 112 Back light 112a 1st LED (1st light source, 1st light emitting element)
112b 2nd LED (2nd light source, 2nd light emitting element)

Claims (6)

A liquid crystal display panel capable of displaying images;
A backlight including one first light source obtained by dividing the plurality of light sources into two and the other second light source, and irradiating the liquid crystal display panel with light;
A power transformer for converting a primary side voltage to a secondary side voltage supplied to the backlight;
A control unit that controls power supplied to the first light source and the second light source, and performs control to alternately and repeatedly flash,
The control section controls the first light source and the second light source to alternately and repeatedly blink so that the timing of turning on and off the first light source and the timing of turning on and off the second light source do not overlap each other. A liquid crystal display device configured to perform   The control unit causes the first light source and the second light source to blink at predetermined intervals, and the timing for turning on the first light source and the timing for turning on the second light source are shifted from each other by a predetermined time. The first light source and the second light source are alternately blinked repeatedly so that the timing of turning on and off the first light source and the timing of turning on and off the second light source do not overlap each other. The liquid crystal display device according to claim 1, configured as described above.   The controller alternately turns the first light source and the second light source so that the timing for turning on the first light source and the timing for turning on the second light source are shifted from each other by a half period of the predetermined period. The liquid crystal display device according to claim 2, wherein the liquid crystal display device is configured to perform control of blinking repeatedly.   The control unit alternately and repeatedly blinks the first light source and the second light source so that the frequency at which the first light source and the second light source blink is a frequency within the audible range of sound. The liquid crystal according to any one of claims 1 to 3, wherein the liquid crystal is configured to perform control so that a frequency of a power change caused by blinking the light source and the second light source is a frequency outside a sound audible range. Display device. The first light source and the second light source each have a plurality of first light emitting elements and a plurality of second light emitting elements,
The control unit includes the plurality of first light-emitting elements and the plurality of first light-emitting elements and the plurality of first light-emitting elements and the plurality of second light-emitting elements so that the timings of turning on and off of the plurality of second light-emitting elements do not overlap each other. 5. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is configured to perform control to alternately and repeatedly blink the second light emitting elements. A liquid crystal display panel capable of displaying images;
A tuner for receiving a television signal;
A backlight including one first light source obtained by dividing the plurality of light sources into two and the other second light source, and irradiating the liquid crystal display panel with light;
A power transformer for converting a primary side voltage to a secondary side voltage supplied to the backlight;
A control unit that controls power supplied to the first light source and the second light source, and performs control to alternately and repeatedly flash,
The control section controls the first light source and the second light source to alternately and repeatedly blink so that the timing of turning on and off the first light source and the timing of turning on and off the second light source do not overlap each other. A liquid crystal television device configured to perform

Images