Surface light-emitting device, liquid crystal display device, and television receiver

Abstract

The present invention relates to a surface light-emitting device, a liquid crystal display device, and a television receiver capable of achieving a wide color gamut.　This surface light-emitting device comprises: a light-emitting unit including a first light source that emits light of a first color and a second light source that emits light of a second color; and a light emission control unit for performing control such that the lighting timings of the first light source and the second light source are different from each other. The techniques of the present invention can be applied to, for example, a liquid crystal display device, a television receiver, or the like.

Description

Surface emitting device, liquid crystal display device, and television receiver

[0001] The present disclosure relates to a surface-emitting device, a liquid crystal display device, and a television receiver, and more particularly to a surface-emitting device, a liquid crystal display device, and a television receiver that are capable of achieving a wide color gamut.

[0002] Patent Document 1 discloses a backlight device having an LED module configured with a magenta light emitter having a structure in which a blue LED is covered with a red phosphor, and a green light emitter consisting of a green LED.

[0003] JP 2016-184498 A

[0004] In a surface-emitting device using two-color LED light sources, a blue LED and a green LED, as in Patent Document 1, when the two color LED light sources emit light simultaneously, there are wavelength bands where the spectra of each LED interfere with each other, making it currently impossible to achieve a wide color gamut.

[0005] The present disclosure has been made in light of these circumstances, and makes it possible to realize a wide color gamut.

[0006] A surface emitting device according to a first aspect of the present disclosure includes a light emitting unit including a first light source that emits light of a first color and a second light source that emits light of a second color, and a light emission control unit that controls the first light source and the second light source to be turned on at different timings.

[0007] A liquid crystal display device according to a second aspect of the present disclosure comprises a surface emitting device including: a light emitting unit including a first light source that emits light of a first color and a second light source that emits light of a second color; and a light emission control unit that controls the first light source and the second light source to be turned on at different timings.

[0008] A television receiver according to a third aspect of the present disclosure comprises a surface light-emitting device including: a light-emitting unit including a first light source that emits light of a first color and a second light source that emits light of a second color; and a light-emitting control unit that controls the first light source and the second light source to be turned on at different timings.

[0009] In the first to third aspects of the present disclosure, a light-emitting unit is provided that includes a first light source that emits light of a first color and a second light source that emits light of a second color, and the first light source and the second light source are controlled to have different lighting timings.

[0010] The surface emitting device, the liquid crystal display device, and the television receiver may be independent devices, or may be internal blocks constituting a single device.

[0011] 1 is a block diagram showing an example of the configuration of an embodiment of a liquid crystal display device to which the technology of the present disclosure is applied. FIG. 1 is an exploded perspective view of the liquid crystal display device of FIG. 1. FIG. 1 is a cross-sectional view showing an example of the configuration of a light-emitting section. FIG. 2 is a diagram showing the excitation spectrum and emission spectrum of a phosphor. FIG. 3 is a cross-sectional view showing another example of the configuration of the light-emitting section. FIG. 4 is a block diagram showing an example of a detailed configuration of a circuit board. FIG. 5 is a timing chart of basic control. FIG. 6 is a timing chart of first light-emitting control. FIG. 7 is a timing chart of second light-emitting control. FIG. 8 is a diagram showing the color reproduction range of the liquid crystal display device of FIG. 1. FIG. 9 is a diagram explaining the effect of the liquid crystal display device of FIG. 1. FIG. 10 is a cross-sectional view showing an example of the shape of a lens of the light-emitting section. FIG. 11 is a cross-sectional view showing an example of the shape of a lens of the light-emitting section. FIG. 12 is a cross-sectional view showing an example of the light-emitting section when a package is not used. FIG. 13 is a cross-sectional view showing an example of the light-emitting section when a package is not used. FIG. 14 is a diagram showing another example of the configuration of the light-emitting section when a package is used. FIG. 15 is a diagram showing a second example of the configuration of a surface light-emitting device. FIG. 16 is a first modified example of the surface light-emitting device according to the second example of the configuration. FIG. 17 is a diagram explaining the effect of a reflective sheet. FIG. 18 is a diagram explaining the effect of a reflective sheet. FIG. 19 is a diagram explaining the effect of a reflective sheet. FIG. 19 is a timing chart of third light-emitting control. FIG. 20 is a timing chart of third light-emitting control.

[0012] Hereinafter, with reference to the accompanying drawings, a description will be given of a mode for carrying out the technology of the present disclosure (hereinafter referred to as an embodiment). Note that in this specification and the drawings, components having substantially the same functional configuration are assigned the same reference numerals to avoid redundant description. The description will be given in the following order: 1. Configuration example of a liquid crystal display device 2. Configuration example of a light-emitting section 3. Configuration example of a drive circuit 4. Light-emitting control for suppressing red afterglow 5. Effects of a liquid crystal display device 6. Examples of lens shapes 7. Other configuration examples of a light-emitting section 8. Second configuration example of a surface-emitting device 9. First modified example of a surface-emitting device according to the second configuration example 10. Second modified example of a surface-emitting device according to the second configuration example 11. Effects of a reflective sheet 12. Third light-emitting control 13. Application to an edge-type liquid crystal display device

[0013] 1. Configuration Example of Liquid Crystal Display Device FIG. 1 is a block diagram showing a configuration example of an embodiment of a liquid crystal display device to which the technology of the present disclosure is applied.

[0014] 1 is a television receiver that displays images of received broadcast signals. The liquid crystal display device 1 has an input unit 11, a tuner 12, and a display module 13. The display module 13 has a signal processing unit 21, a surface light-emitting device 22, a liquid crystal control unit 23, and a liquid crystal panel 24. The surface light-emitting device 22 is a so-called backlight device that illuminates the liquid crystal panel 24 from the back side, and has a light-emitting control unit 31 and a light-emitting panel 32.

[0015] The input unit 11 is configured by, for example, an input terminal of an HDMI terminal (HDMI is a registered trademark), acquires a broadcast signal received via an antenna or the like, and outputs it to the tuner 12. The tuner 12 selects the broadcast signal, demodulates it, and extracts a video signal. The extracted video signal is output to the signal processing unit 21.

[0016] Signal processing unit 21 performs predetermined video signal processing based on the input video signal. For example, signal processing unit 21 generates a liquid crystal control signal for driving (the liquid crystal of) liquid crystal panel 24 based on the input video signal, and outputs the signal to liquid crystal control unit 23. Signal processing unit 21 also generates a light-emission control signal for driving light-emitting panel 32 based on the input video signal, and outputs the signal to light-emission control unit 31.

[0017] The liquid crystal control unit 23 drives the liquid crystal of each pixel of the liquid crystal panel 24 based on a liquid crystal control signal from the signal processing unit 21, generates a liquid crystal drive signal that changes the transmittance, and outputs it to the liquid crystal panel 24. The liquid crystal panel 24 is a panel in which pixels, each including a color filter, a liquid crystal element, and a TFT (Thin Film Transistor) element, are arranged two-dimensionally, and displays an image by changing the transmittance (aperture ratio) according to the liquid crystal drive signal from the liquid crystal control unit 23 and modulating the light emitted from the light-emitting panel 32. The color filter is composed of any one of red (R), green (G), and blue (B), and light that has passed through the liquid crystal element passes through the color filter and is emitted in the color of the color filter.

[0018] Based on the light-emission control signal from the signal processing unit 21, the light-emission control unit 31 generates an LED drive signal for driving an LED arranged on the light-emitting panel 32, and outputs the signal to the light-emitting panel 32. The light-emitting panel 32 is a panel in which a plurality of LEDs (Light Emitting Diodes) are arranged two-dimensionally in correspondence with the image display area of ​​the liquid crystal panel 24. The light-emitting panel 32 causes the LEDs to emit light based on the LED drive signal input from the light-emission control unit 31 corresponding to each LED.

[0019] The liquid crystal display device 1 is configured as described above and displays the video of the received broadcast signal. Note that the liquid crystal display device 1 may not have the tuner 12 and may be a monitor (display) that displays the video corresponding to the video signal input from an external device.

[0020] FIG. 2 is an exploded perspective view of the liquid crystal display device 1 showing the relative positions of the liquid crystal panel 24 and the light-emitting panel 32. As shown in FIG.

[0021] The liquid crystal display device 1 is constructed by stacking, in order from the front side of the device, which is the user side, a bezel 51, a liquid crystal panel 24, multiple optical sheets 52 (52A, 52B), a light-emitting panel 32, a back chassis 53, and a control board 54.

[0022] The bezel 51 is formed in a substantially rectangular frame shape. The plurality of optical sheets 52 is composed of, for example, two optical sheets 52A and 52B. The optical sheets 52A and 52B are composed of, for example, a polarized reflective sheet, a prism sheet, a diffusion sheet, or the like. The plurality of optical sheets 52 may be composed of three or more sheets.

[0023] The light-emitting panel 32 includes multiple circuit boards 61 and a reflecting sheet 62. Each circuit board 61 is equipped with multiple LEDs as light-emitting units 63. An LED driver for driving the LEDs of the light-emitting units 63 is mounted on the circuit board 61. The reflecting sheet 62 has openings formed at the positions of the LEDs, and the reflecting sheet 62 reflects light emitted from the LEDs arranged in the openings forward toward the optical sheet 52. Each of the multiple circuit boards 61 is connected to a control board 54 attached to the rear surface of the back chassis 53. The control board 54 is electrically connected to each of the multiple circuit boards 61 and controls each circuit board 61. For example, one circuit board 61 corresponds to one divided area obtained by dividing the entire display area of ​​the liquid crystal display device 1 into multiple small areas (hereinafter referred to as divided areas). The control board 54 is capable of so-called local dimming control, which controls the light-emitting brightness of each divided area by independently controlling the light-emitting brightness of the light-emitting units 63 of each of the multiple circuit boards 61. The light emission control unit 31 in FIG. 1 corresponds to at least some of the plurality of circuit boards 61 and the control board 54 .

[0024] The liquid crystal display device 1 configured as described above is an LED direct type liquid crystal display device in which the light emitting section 63 (light emitting panel 32 ) is arranged directly below the liquid crystal panel 24 .

[0025] 2, for simplicity, an example in which the light-emitting panel 32 has six circuit boards 61 is shown, but the number of circuit boards 61 is arbitrary. Also, although the example is shown in which each circuit board 61 has one light-emitting unit 63, a configuration in which multiple light-emitting units 63 are arranged on each circuit board 61 and the circuit board 61 causes the multiple light-emitting units 63 to emit light may also be used.

[0026] 2. Configuration Example of Light Emitting Section FIG. 3 is a cross-sectional view showing a configuration example of the light emitting section 63. As shown in FIG.

[0027] The light-emitting unit 63 is configured by arranging a blue LED 101 and a green LED 102 in a package 103. The blue LED 101 and the green LED 102 are each arranged on the bottom surface inside the concave package 103 and are covered with a resin material 104 containing a dispersed phosphor 105. The package 103 is a housing that houses the blue LED 101, the green LED 102, and the resin material 104 containing the phosphor 105, and is configured as a concave shape having four side walls and a bottom. The package 103 is made of, for example, a resin material. A lens 106 that diffuses light emitted from the package 103 is arranged on the top surface of the concave package 103. The outer bottom surface of the package 103 is fixed onto the circuit board 61.

[0028] The blue LED 101 emits blue light (first color) with a wavelength in the range of 430 to 480 nm, for example, and a peak wavelength of 450 to 465 nm. The green LED 102 emits green light (second color) with a wavelength in the range of 500 to 560 nm, for example, and a peak wavelength of 520 to 540 nm. The phosphor 105 is a phosphor that is excited by blue light and emits red light (third color), and is made of, for example, a fluoride phosphor (KSF).

[0029] The light-emission control unit 31 can independently control (drive) the two light sources of color, the blue LED 101 and the green LED 102 of the light-emitting unit 63. When blue light is emitted from the blue LED 101 under the control of the light-emission control unit 31, red light is also emitted by the phosphor 105, and as a result, magenta light is emitted in the direction forward of the liquid crystal panel 24. On the other hand, when green light is emitted from the green LED 102 under the control of the light-emission control unit 31, the phosphor 105 does not react, and so the green light is emitted in the direction forward of the liquid crystal panel 24.

[0030] FIG. 4 shows the excitation spectrum and emission spectrum of the phosphor 105.

[0031] As shown in Figure 4, phosphor 105 has a low excitation spectrum intensity in the green wavelength region of 520 nm or more, so it is not excited by green light and does not emit light. Therefore, even if two light sources, blue LED 101 and green LED 102, are housed in one package 103, the emission brightness of magenta and green can be controlled independently. By housing blue LED 101 and green LED 102 in one package 103, the number of mounted LEDs can be reduced, and manufacturing costs can be suppressed.

[0032] Considering cost and other factors, it is desirable to provide two light sources of colors, the blue LED 101 and the green LED 102, in the same package as described above. However, as shown in FIG. 5 , the blue LED 101 and the green LED 102 may be provided in separate packages 103. In the example of FIG. 5 , one package 103 includes either the blue LED 101 or the green LED 102. The package 103 (first package 103) in which the blue LED 101 is disposed is filled with a resin material 104 containing a phosphor 105. The package 103 (second package 103) in which the green LED 102 is disposed is filled with a resin material 104 that does not include the phosphor 105. Although the resin material 104 in the package 103 in which the blue LED 101 is disposed and the resin material 104 in the package 103 in which the green LED 102 is disposed are made of the same material, they may be made of different materials.

[0033] In the above example, the phosphor 105, which is made of a fluoride phosphor or the like, is blended into the resin material 104 as a wavelength conversion material that emits red light in response to the blue light emitted by the blue LED 101. However, other wavelength conversion materials that emit red light in response to blue light may also be blended into the resin material 104. For example, instead of the phosphor 105, quantum dots that convert blue light into red light may be blended into the resin material 104. Alternatively, both the phosphor 105 and the quantum dots may be incorporated into the resin material 104.

[0034] 3. Example of Drive Circuit Configuration FIG. 6 is a block diagram showing an example of the detailed configuration of the circuit board 61 as a drive circuit for driving the two color light sources, the blue LED 101 and the green LED 102. As shown in FIG.

[0035] The circuit board 61 includes a controller 121 , a blue LED driver 122 , a blue LED anode voltage generating circuit 123 , a green LED driver 124 , and a green LED anode voltage generating circuit 125 .

[0036] The control board 54 determines the light emission brightness for each divided area based on the light emission control signal supplied from the signal processing unit 21, and outputs a light emission control signal according to the light emission brightness to the controller 121 of the circuit board 61 corresponding to each divided area.

[0037] The controller 121 determines the magenta light emission luminance according to the light emission luminance determined by the control board 54, and determines the current value to be passed through the blue LED 101 and the frequency and duty ratio of the PWM signal. The controller 121 outputs the determined current value, frequency and duty ratio of the PWM signal to the blue LED driver 122.

[0038] The controller 121 also determines the green light emission luminance according to the light emission luminance determined by the control board 54, and determines the current value to be passed through the green LED 102, as well as the frequency and duty ratio of the PWM signal. The controller 121 outputs the determined current value, frequency and duty ratio of the PWM signal to the green LED driver 124.

[0039] Blue LED driver 122 lights up blue LED 101 at the current value, frequency of the PWM signal, and duty ratio determined by controller 121. Blue LED driver 122 lights up blue LED 101 by supplying a PWM signal to the cathode terminal of blue LED 101.

[0040] Blue LED anode voltage generating circuit 123 is connected to the anode of blue LED 101 , and supplies an anode voltage to the anode of blue LED 101 under the control of blue LED driver 122 .

[0041] The green LED driver 124 lights up the green LED 102 at the current value, frequency and duty ratio of the PWM signal determined by the controller 121. The green LED driver 124 lights up the green LED 102 by supplying a PWM signal to the cathode terminal of the green LED 102.

[0042] Green LED anode voltage generating circuit 125 is connected to the anode of green LED 102 and supplies an anode voltage to the anode of green LED 102 under the control of green LED driver 124 .

[0043] When the light source is configured with a plurality of blue LEDs 101 and a plurality of green LEDs 102, the plurality of blue LEDs 101 are connected in series, and the plurality of green LEDs 102 are also connected in series.

[0044] 4. Light Emission Control to Suppress Red Afterglow By using phosphor 105 instead of a red LED, high light emission efficiency and a long life can be achieved. However, if the driving of blue LED 101 is synchronized with the driving of liquid crystal panel 24 to improve video response, there is a concern that red afterglow may be visible due to a delay in the light emission response of phosphor 105. Therefore, when the blue LED 101 and green LED 102 are caused to emit light in synchronization with the driving of liquid crystal panel 24, controller 121 controls the timing of lighting blue LED 101 and green LED 102 to be different from each other, thereby suppressing afterglow.

[0045] 7 to 9, the light emission control that can be performed by the controller 121 to suppress red afterglow will be described.

[0046] First, with reference to the timing chart in Fig. 7, we will explain light emission control in which the lighting timing of the blue LED 101 and the green LED 102 is perfectly synchronized with the driving of the liquid crystal panel 24. The light emission control explained in Fig. 7 is the control that serves as the basis for the light emission control explained later in Fig. 8 and Fig. 9, and is called basic control.

[0047] The timing chart in Figure 7 shows the driving of the liquid crystal of the liquid crystal panel 24 of a specific pixel of the liquid crystal display device 1 and the light emission states of blue, green, and red in response to the driving of the blue LED 101 and green LED 102.

[0048] In Figure 7, the liquid crystal drive signal in the first row from the top represents the liquid crystal drive signal that drives the liquid crystal of a specific pixel of the liquid crystal panel 24, with Hi (High) representing an open shutter and Lo (Low) representing a closed shutter. LC in the second row from the top represents the actual open / close state of the liquid crystal according to the liquid crystal drive signal, with the maximum value representing a 100% aperture ratio and the minimum value representing a 0% aperture ratio. The blue and green waveforms represent the light emission brightness according to the PWM signals supplied to the blue LED 101 and green LED 102, with Hi (High) representing on and Lo (Low) representing off. The red waveform represents the light emission brightness of the phosphor 105. The Hi period of the PWM signal supplied to the blue LED 101 and green LED 102 is L time, and a current value H is supplied to the blue LED 101 during the Hi period of the PWM signal.

[0049] 7, the blue LED 101 and green LED 102 are driven to turn on and off in perfect agreement with the Hi (shutter open) and Lo (shutter closed) liquid crystal drive signal, i.e., at the same timing as the liquid crystal drive signal. Because the liquid crystal open / closed state LC responds slowly to the input voltage due to material properties, there is a delay, as shown in FIG. 7, before the liquid crystal drive signal changes to the shutter open or closed state.

[0050] In the red waveform, a hatched area 151 indicates a state in which red afterglow is generated even though the blue LED 101 is turned off.

[0051] FIG. 8 shows a timing chart of the first light emission control, which controls the basic control of FIG. 7 so as to suppress red afterglow.

[0052] In the first light emission control, the timing at which the blue LED 101 starts to light is advanced by a predetermined time d1 from the timing at which the liquid crystal shutter opens, and the current value H' of the blue LED 101 is controlled so that the light emission brightness of the blue LED 101 is higher by h1 than in basic control. Because the lighting time (Hi period) of the blue LED 101 remains the same as in basic control, the timing at which the blue LED 101 stops lighting is also advanced by the predetermined time d1 from the basic control. Comparing the lighting start timings of the blue LED 101 and the green LED 102, the blue LED 101 lights up first and the green LED 102 lights up after a delay, so the lighting start timings of the blue LED 101 and the green LED 102 are different.

[0053] By activating the blue LED 101 a predetermined time d1 earlier than the liquid crystal shutter opening timing and turning off the blue LED 101 earlier than the liquid crystal shutter closing timing, the amount of red afterglow can be reduced compared to the basic control in Figure 7, as shown in area 152. Because the period during which blue is visible is the period during which the liquid crystal open / close state LC is in the open state, the emission brightness of the blue LED 101 is increased by h1 by the amount of the predetermined time d1 shift, thereby maintaining the emission brightness and emission time of RGB. However, turning on the blue LED 101 too early increases power loss, so the predetermined time d1 is adjusted to maintain the total intensity of RGB (white balance).

[0054] As in the example of FIG. 8, by adjusting the timing at which the blue LED 101 starts to light up and the light emission brightness (current value), the amount of red afterglow can be reduced.

[0055] FIG. 9 shows a timing chart of the second light emission control, which controls the basic control of FIG. 7 so as to suppress red afterglow.

[0056] In the second light-emission control, the timing at which the blue LED 101 starts to light up is the same as the timing at which the liquid crystal shutter opens, but the timing at which the light ends is earlier than the timing at which the liquid crystal shutter closes by a predetermined time d2. The lighting time (Hi period) of one pulse of the blue LED 101 is time L', which is shorter than that of the basic control by the predetermined time d2. As in the first light-emission control, the current value H" of the blue LED 101 is controlled so that the light emission brightness of the blue LED 101 is higher by h2. Comparing the lighting timings of the blue LED 101 and the green LED 102, the blue LED 101 and the green LED 102 start to light up at the same time and the green LED 102 turns off with a delay after the blue LED 101 turns off, so the lighting end timings are different. Comparing the lighting times of one pulse of the blue LED 101 and the green LED 102, the lighting time of the blue LED 101 is shorter than the lighting time of the green LED 102.

[0057] By advancing the timing of the blue LED 101's end of illumination by a predetermined time d2 relative to the timing of the liquid crystal shutter opening, the amount of red afterglow can be reduced compared to the basic control in Figure 7, as shown in area 153. Because the period during which blue is visible is the period during which the liquid crystal open / close state LC is open, the emission brightness of the blue LED 101 is increased by h2 by the amount of time d2 that the end of illumination is advanced, thereby maintaining the emission brightness and emission time of RGB. However, because turning off the blue LED 101 too early increases power loss, the predetermined time d2 is adjusted to maintain the total intensity of RGB (white balance).

[0058] As in the example of FIG. 9, by adjusting the lighting period and light emission brightness (current value) of the blue LED 101, the amount of red afterglow can be reduced.

[0059] It is also possible to perform light emission control by combining both the lighting start timing of the blue LED 101 shown in the example of Fig. 8 and the lighting period of the blue LED 101 shown in the example of Fig. 9. That is, the lighting start timing of the blue LED 101 may be advanced by a predetermined time d1 from the timing of closing the liquid crystal shutter, and the lighting period (Hi period) of the blue LED 101 may be set to L', which is shorter by a predetermined time d2 than in basic control.

[0060] As described above, the controller 121 can suppress red afterglow by differentiating the timing of turning on the blue LED 101, specifically at least one of the timing of starting or ending the lighting, from the timing of opening and closing the liquid crystal shutter, and by adjusting the light emission brightness. Because the timing of opening and closing the liquid crystal shutter and the timing of turning on the green LED 102 are the same, the controller 121 controls the timing of turning on the blue LED 101 and the green LED 102 so that the timings are different.

[0061] 8 and 9 are examples of control of the light-emitting unit 63 corresponding to one divided area. The predetermined times d1 and d2 and the increase amounts h1 and h2 in light emission brightness differ for each divided area of ​​the liquid crystal display device 1 according to the input video signal.

[0062] 5. Effects of the Liquid Crystal Display Device FIG. 10 is a diagram showing the color reproduction range of the liquid crystal display device 1 shown on the CIE1979 (u',v') chromaticity diagram.

[0063] 10, a solid line 201 indicates the color reproduction range of the liquid crystal display device 1. A dashed line 202 indicates the color reproduction range of the digital cinema standard established by the industry group Digital Cinema Initiatives (DCI). A dotted line 203 indicates the color reproduction range of ITU-R Recommendation BT.2020, a broadcasting standard. The gray dots on the chromaticity diagram represent pointer colors.

[0064] The color reproduction range of the liquid crystal display device 1 can cover the color reproduction range of DCI and BT.2020. In addition, the color reproduction range of the pointer color distribution can be realized, and a wide color gamut can be reproduced.

[0065] The liquid crystal display device 1 can independently control the current value and duty ratio of the blue LED 101 and the green LED 102, which are the two color light sources that make up the light-emitting unit 63. This allows for a boost in brightness by concentrating power on pixels that are close to the pure colors of blue, green, and red, and allows for a clearer image to be displayed compared to other methods using the same power. For example, for pixels that display a green image that is close to the pure color, a bright green image can be output by reducing the current of the blue LED 101 and diverting the remaining current to the green LED 102 to increase the current.

[0066] Generally, in a backlight using three color LEDs (blue, green, and red), the red LED has different lifespan characteristics and electrical characteristics from the blue and green LEDs, so individual control of the red LED, such as correction control to maintain white balance, is required, resulting in problems such as increased costs and rapid performance degradation.The liquid crystal display device 1 does not use a red LED, but instead outputs red light using a wavelength conversion material such as phosphor 105 or quantum dots, thereby achieving a long lifespan.

[0067] Since the liquid crystal display device 1 can independently drive two colors, blue LED 101 and green LED 102, it can achieve high light-emitting efficiency by controlling the liquid crystal of the liquid crystal panel 24 to an open shutter state in response to a video signal and reproducing an image close to the color of the video signal using the surface-emitting device 22 on the backlight side.

[0068] Therefore, the liquid crystal display device 1 can achieve a wide color gamut, high luminous efficiency, and a long lifespan.

[0069] The blue LED 101 of the surface light emitting device 22 is configured to emit blue light with a peak wavelength of 450 nm or more. By setting the peak wavelength of the light emitted by the blue LED 101 to 450 nm or more, the relative energy received by the user (viewer) watching the video can be reduced, making it possible to reduce eye fatigue.

[0070] Figure 11 shows a comparison of the relative energy received by a viewer at the same luminance when the wavelength of the blue LED is changed.

[0071] The peak wavelength of around 430 to 440 nm used in general television sets has high relative energy and low luminosity, causing high stress on the viewer's eyes.By using blue LEDs 101 with a peak wavelength of 450 nm or more, the liquid crystal display device 1 suppresses the relative energy and reduces stress on the eyes, realizing a display that is gentle on the eyes.

[0072] FIG. 12 is a diagram showing the color reproduction range of a backlight that is not independently driven on the chromaticity diagram shown in FIG.

[0073] The solid line 205 indicates the color reproduction range of a backlight that emits white light using, for example, a blue LED and red and green phosphors. In a backlight that emits white light using a blue LED and red and green phosphors, the peak wavelength of the blue LED is set to approximately 430 to 440 nm to achieve both relative energy suppression and a wide color reproduction range. If the peak wavelength of the blue LED were set to approximately 450 nm to suppress the relative energy, the pure blue color portion of DCI and BT.2020 would not be covered, as shown by the solid line 205. In contrast, the surface-emitting device 22 of the liquid crystal display device 1 independently drives the blue LED 101 and green LED 102, enabling reproduction of shorter wavelengths as indicated by the arrows, even when the peak wavelength is set to 450 nm or longer, thereby achieving the color reproduction range indicated by the solid line 201.

[0074] 13 is a cross-sectional view showing an example of the shape of the lens 106 formed on the top surface of the concave package 103. In Fig. 13, the example of Fig. 5 in which one blue LED 101 is arranged in one package 103 will be described, but the same applies to the case in which a green LED 102 is arranged, or the case in which the blue LED 101 and the green LED 102 are provided in the same package as in Fig. 3.

[0075] Fig. 13A is a diagram showing the shape of the lens 106 shown in Fig. 5. In Fig. 13A, the light exit surface of the lens 106 that emits light from the blue LED 101 is formed in a convex shape.

[0076] Fig. 13B is a diagram showing a first modified example showing another example shape of lens 106. The light exit surface of lens 106 in Fig. 13B has a concave shape. For example, the light exit surface of lens 106 in Fig. 13B has an inverted pyramid shape in plan view, with the central part of a rectangle in which blue LED 101 is arranged being the flat surface that is most recessed toward blue LED 101. The light exit surface of lens 106 may be formed of a curved surface instead of a combination of flat surfaces.

[0077] Fig. 13C is a diagram showing a second modified example showing another example shape of lens 106. The shape of the light exit surface of lens 106 in Fig. 13B has a shape that combines a convex shape and a concave shape. In the light exit surface of lens 106 in Fig. 13C, the rectangular central portion where blue LED 101 is arranged is formed as a concave shape in plan view, and the portion between the rectangular central portion and the rectangular outer periphery is formed as a convex shape in plan view.

[0078] As described above, the lens 106 is formed in a shape that has at least a protrusion in the light output direction, which is the side on which the light emitting panel 32 is disposed.

[0079] FIG. 14 is a cross-sectional view showing another example of the shape of the lens 106. In FIG.

[0080] 13 shows an example in which the lens 106 is formed only on the top surface of the package 103, but the lens 106 may be formed so as to also cover the side surfaces of the package 103, as shown in A to C of Figures 14. The lenses 106 in Figures 14A to 14C show examples in which the lenses 106 in Figures 13A to 13C are modified so as to also cover the side surfaces of the package 103.

[0081] FIG. 14 shows an example in which one blue LED 101 is arranged in one package 103, but the same formation can also be achieved in the case in which a green LED 102 is arranged, or in the case in which a blue LED 101 and a green LED 102 are provided in the same package as in FIG. 3.

[0082] 15 and 16 are cross-sectional views showing examples of the light-emitting section 63 when the package 103 is not used.

[0083] The package 103 is not essential, and the light-emitting unit 63 can be configured without using the package 103. When the package 103 is not used, a resin material 104 containing a phosphor 105 is formed so as to cover the top and side surfaces of the blue LED 101, and a lens 106 is formed outside the resin material 104, as shown in FIG.

[0084] When the light source is a green LED 102 and does not need to include phosphor 105, a lens 106 is formed to cover the top and side surfaces of the green LED 102, as shown in FIGS.

[0085] When two color light sources, a blue LED 101 and a green LED 102, are arranged without using a package 103, as in the example of Figure 15, a resin material 104 containing a phosphor 105 is formed on the top and side surfaces of the blue LED 101 and the green LED 102, and a lens 106 is formed outside the resin material 104.

[0086] The material of the lens 106 may be any transparent resin material, such as epoxy resin. Other organic materials such as styrene resin, acrylic resin, styrene-acrylic copolymer resin, and silosane resin may also be used as the material of the lens 106. Silicon may also be used as the material of the lens 106. Silicon includes amorphous silicon and polycrystalline silicon. The material of the lens 106 may also contain diffusion beads with different refractive indices to provide a color mixing effect.

[0087] The lens 106 can be manufactured by, for example, dropping the material of the lens 106 into a mold and molding it. The lens shape may be formed by adjusting the pressure and amount when dropping the material of the lens 106.

[0088] 17 is a diagram showing another example of the configuration of the light emitting unit 63 when using the package 103. A of Fig. 17 is a plan view of the light emitting unit 63, and B of Fig. 17 is a cross-sectional view of the light emitting unit 63.

[0089] The light-emitting unit 63 shown in FIG. 17 has a configuration in which two light sources, a blue LED 101 and a green LED 102, are provided in the same package. This configuration differs from the configuration shown in FIG. 3 in that a single package 103 has two housing sections, a first housing section and a second housing section, each of which is recessed and separated by a wall. One of the first housing section and the second housing section houses a blue LED 101 and a resin material 104 containing phosphor 105, while the other houses a green LED 102 and a resin material 104 not containing phosphor 105. As with the above-described example, quantum dots may be provided instead of or together with phosphor 105. The top surfaces of the resin material 104 filled in the first housing section and the second housing section are flush with the top surface of the package 103. In this way, the light emitting section 63 may be configured such that the blue LED 101 and the green LED 102 are disposed in separate housing sections of a single package 103 .

[0090] 18 is a diagram showing a second configuration example of the surface light emitting device 22, which is another form of the surface light emitting device 22. Fig. 18 corresponds to a cross-sectional view of the plate-shaped surface light emitting device 22 as viewed from the side.

[0091] The surface light-emitting device 22 shown in Fig. 18 includes a circuit board 61, blue LEDs 101 and green LEDs 102 provided on the circuit board 61, and multiple optical sheets 52 arranged in front of the circuit board 61 in the light emission direction. For ease of explanation, the multiple optical sheets 52 are shown spaced apart at a predetermined distance in Fig. 18 , but in reality, the multiple optical sheets 52 are stacked in close contact. There is a predetermined gap between the blue LEDs 101 and green LEDs 102 and the multiple optical sheets 52, forming an air layer. The multiple optical sheets 52 are composed of, from the LED light source side, a diffusion plate 52P, a fluorescent sheet 52Q, and another optical sheet 52R, for example.

[0092] Of the multiple optical sheets 52, the lowest diffusion plate 52P closest to the LED light source is an optical sheet that serves as a support substrate when laminating the fluorescent light-emitting sheet 52Q and other optical sheets 52R, and because it has a predetermined thickness (e.g., 2 mm), it is called the diffusion plate 52P rather than a diffusion sheet, but is actually a type of optical sheet 52. The diffusion plate 52P diffuses light from the blue LEDs 101 and green LEDs 102 over the expanse of its surface.

[0093] Fluorescent sheet 52Q is a sheet containing phosphor 105 that is excited by blue light and emits red light. When blue LED 101 provided on circuit board 61 emits blue light, red light is also emitted by phosphor 105, resulting in magenta light being emitted forward toward liquid crystal panel 24. As described with reference to Fig. 4, phosphor 105 has a low excitation spectrum intensity in the green wavelength region of 520 nm or more, and therefore is not excited by the green light of green LED 102 to emit light.

[0094] More specifically, as shown on the right side of FIG. 18 , the fluorescent sheet 52Q has a laminated structure in which a resin sheet 212 is sandwiched between two substrates 211 such as PET (polyethylene terephthalate). The resin sheet 212 is formed by diffusing phosphor 105, such as a fluoride phosphor, in a resin material 213. The two substrates 211 on either side also function to protect the resin sheet 212 from moisture and the like. Similar to the resin material 104 in the package 103 described above, quantum dots that convert blue light to red light may be blended in place of the phosphor 105, and both the phosphor 105 and the quantum dots may be incorporated into the resin material 213.

[0095] The other optical sheet 52R is configured by, for example, the polarizing reflective sheet and prism sheet described with reference to FIG.

[0096] The circuit board 61 in Figure 18 and the blue LED 101 and green LED 102 provided thereon correspond to a specific one of the circuit boards 61 and light-emitting units 63 arranged in the light-emitting panel 32 in Figure 2.

[0097] 3, 5, 15, 17, etc., resin material 104 containing phosphor 105 is formed so as to cover the top and side surfaces of blue LED 101 or green LED 102, but light-emitting section 63 in Fig. 18 is composed of blue LED 101 and green LED 102 provided on circuit board 61 and fluorescent light-emitting sheet 52Q out of multiple optical sheets 52. Surface light-emitting device 22 according to the second configuration example is composed of light-emitting panel 32 and multiple optical sheets 52.

[0098] By providing the fluorescent light-emitting sheet 52Q, which includes the phosphor 105 made of a fluoride phosphor or the like, as part of the multiple optical sheets 52, the fluorescent light-emitting sheet 52Q can be easily replaced even if it deteriorates. LED light sources generally have a long lifespan, and by separating the fluorescent light source from the phosphor 105, a new, environmentally friendly device can be provided. Furthermore, since the fluorescent light-emitting sheet 52Q is positioned at a predetermined distance from the LED light sources (blue LEDs 101 and green LEDs 102), which are heat-generating elements, the fluorescent light-emitting sheet 52Q can have a longer lifespan and higher efficiency.

[0099] 9. First Modification of Surface Light Emitting Device According to Second Configuration Example FIG. 19 is a diagram showing a first modification of the surface light emitting device 22 according to the second configuration example.

[0100] In the first modified example shown in Fig. 19, the diffusion plate 52P and the fluorescent-emitting sheet 52Q in Fig. 18 are replaced with a single diffusion plate 52P'. In the basic configuration in Fig. 18, the fluorescent-emitting sheet 52Q containing the phosphor 105 is provided separately from the diffusion plate 52P, but in the first modified example in Fig. 19, the phosphor 105 is contained in the diffusion plate 52P'. More specifically, as shown on the right side of Fig. 19, the diffusion plate 52P' has a structure in which the phosphor 105 is dispersed in a plastic material 221 such as PS (polystyrene).

[0101] The configuration is the same as that of the surface light emitting device 22 of FIG. 18, except that the diffusion plate 52P and the fluorescent light emitting sheet 52Q of FIG. 18 are replaced with a single diffusion plate 52P'.

[0102] 10. Second Modification of Surface Light Emitting Device According to Second Configuration Example FIG. 20 is a diagram showing a second modification of the surface light emitting device 22 according to the second configuration example.

[0103] The second modification shown in FIG. 20 further includes a reflective sheet 52X between the diffuser plate 52P and fluorescent sheet 52Q shown in FIG. 18, which can control the reflectance of each wavelength with respect to the incident angle. The reflective sheet 52X is composed of a multilayer laminated film made up of multiple films with different refractive indices. The laminated films can be made of materials such as SiO2, titanium oxide (TiO2), and STO (strontium titanium oxide). The reflective sheet 52X can be designed to reflect light of any target wavelength by changing the type and thickness of the films. In the example shown in FIG. 20, the reflective sheet 52X is disposed below (on the light source side of) the fluorescent sheet 52Q. However, the reflective sheet 52X may also be disposed above the fluorescent sheet 52Q.

[0104] In the first and second modifications, the wavelength conversion material that converts blue light to red light is formed into a sheet and provided as part of the plurality of optical sheets 52, thereby enabling easy replacement and providing a new, environmentally friendly device. Furthermore, since the phosphor 105 is disposed at a predetermined distance from the LED light source, which is a heat source, the phosphor 105 can have a long life and be highly efficient.

[0105] 11. Effects of Reflective Sheet The effects of the reflective sheet 52X will be described with reference to FIGS.

[0106] FIG. 21 is a diagram illustrating light emission when there is no reflective sheet 52X.

[0107] When blue light is output by the blue LED 101, red light is also emitted by the fluorescent light-emitting sheet 52Q, resulting in magenta light being emitted forward (upward in FIG. 21 ). Comparing the magenta directly above the blue LED 101 with the magenta around the blue LED 101 in a plan view, in the area around the blue LED 101, as shown in FIG. 21 , blue light that is reflected by the fluorescent light-emitting sheet 52Q and the like and then reflected again by the circuit board 61 also enters the fluorescent light-emitting sheet 52Q. Light that is obliquely incident on the fluorescent light-emitting sheet 52Q takes a longer time (optical path length) to travel through the fluorescent light-emitting sheet 52Q than light that is incident directly above the blue LED 101, and therefore the red color around the blue LED 101 is stronger than that directly above the blue LED 101. Therefore, in plan view, the magenta color around the blue LED 101 is reddish compared to the magenta color directly above the blue LED 101 .

[0108] 22, by disposing a reflective sheet 52X between a diffuser plate 52P and a fluorescent sheet 52Q and reflecting obliquely incident blue light, the magenta (red) color unevenness described above can be suppressed. Similarly, for the green light output from the green LED 102, a configuration can be adopted that controls the reflection of obliquely incident green light. By controlling the blue and green light, it is possible to suppress the ring-shaped color unevenness that occurs around the LED light source during local dimming.

[0109] FIG. 23 is a diagram illustrating the difference in effect depending on the arrangement of the reflective sheet 52X.

[0110] 23A shows a case where a reflective sheet 52X is placed below a fluorescent light-emitting sheet 52Q. When the reflective sheet 52X is placed below a fluorescent light-emitting sheet 52Q, as described above, it is possible to suppress color unevenness in red by reflecting obliquely incident blue light.

[0111] 23B shows a case where a reflective sheet 52X is placed on top of the fluorescent light-emitting sheet 52Q. When the reflective sheet 52X is placed on top of the fluorescent light-emitting sheet 52Q, it is possible to suppress uneven red color in the peripheral area of ​​the blue LED 101 in a planar view by reflecting obliquely incident red light. In other words, the fluorescent light-emitting sheet 52Q suppresses the transmission of obliquely incident red light in the peripheral area of ​​the blue LED 101, thereby adjusting the balance between obliquely incident blue light and red light.

[0112] The liquid crystal panel 24 has an angular characteristic due to its structure. As shown in FIG. 24 , the liquid crystal panel 24 controls the liquid crystal molecules 242 by controlling the voltage applied to two light distribution films 241. By controlling the liquid crystal molecules 242, the aperture ratio changes from 0% in the closed state shown in FIG. 24 A to 100% in the open state shown in FIG. 24 C, passing through the intermediate state shown in FIG. 24 B. In the intermediate state shown in FIG. 24 B, some light from the liquid crystal panel 24 leaks and is visible when the viewing angle is oblique. When a reflective sheet 52X is placed above a fluorescent sheet 52Q as shown in FIG. 23 B, it is possible to correct color unevenness visible at oblique viewing angles.

[0113] 12. Third Light Emission Control FIG. 25 shows a timing chart of the third light emission control by the controller 121. In FIG.

[0114] In the first light-emitting control described in Fig. 8 and the second light-emitting control described in Fig. 9, the controller 121 controls the blue LED 101 and the green LED 102 so that their lighting periods partially overlap. For example, in the first light-emitting control shown in Fig. 8, the blue LED 101 lights up first by a predetermined time d1, and the green LED 102 lights up after a delay, so that the blue LED 101 and the green LED 102 are simultaneously lit for a predetermined period. In the second light-emitting control shown in Fig. 9, the blue LED 101 and the green LED 102 start lighting up simultaneously, and the lighting of the blue LED 101 ends earlier than the green LED 102 by a predetermined time d2.

[0115] In contrast, in the third light emission control shown in FIG. 25 , the controller 121 controls the blue LED 101 and the green LED 102 so that their lighting periods do not overlap in a time-division manner. Specifically, the controller 121 lights the blue LED 101 for the BT time, then provides a first waiting time Ta, and after the first waiting time Ta has elapsed, lights the green LED 102 for the GT time. A second waiting time Tb is provided after the lighting period (GT time) of the green LED 102 ends, and after the second waiting time Tb has elapsed since the lighting of the green LED 102 ended, the blue LED 101 starts lighting again. A cycle of lighting the blue LED 101 for the BT time, the first waiting time Ta, lighting the green LED 102 for the GT time, and the second waiting time Tb is repeated. The first waiting time Ta and the second waiting time Tb are times during which neither the blue LED 101 nor the green LED 102 is lit.

[0116] It does not matter whether the blue LED 101 or the green LED 102 is turned on first, but there is a first waiting time Ta between the end of lighting of the blue LED 101 and the start of lighting of the green LED 102. The second waiting time Tb is shorter than the first waiting time Ta (Ta > Tb) and may be zero (Tb = 0). Figure 26 shows an example of the third light-emission control in which the second waiting time Tb is set to zero and the green LED 102 is turned on.

[0117] In the third light-emission control shown in Figures 25 and 26, the sum of the BT time during which the blue LED 101 emits light, the first waiting time Ta, the GT time during which the green LED 102 emits light, and the second waiting time Tb (Tb = 0) corresponds to one frame period of the video, and the liquid crystal of the liquid crystal panel 24 is driven in tandem for each frame. The R, G, and B colors of one frame period are combined and perceived by the user (viewer) as an image. The first waiting time Ta is the period during which red is emitted in response to the emission of the blue LED 101. By providing the first waiting time Ta and shifting the emission period of magenta (blue + red) and the emission period of green, and thereby suppressing interference between the R, G, and B colors, a wide color gamut can be achieved. Therefore, the third light-emission control allows a wide color gamut to be achieved.

[0118] 13. Application to Edge-Type Liquid Crystal Display Devices In the above-described embodiment, a direct-type surface light-emitting device 22 has been described in which the blue LEDs 101 and the green LEDs 102 are arranged directly below the liquid crystal panel 24. The light emission control by the light-emission control unit 31 described above can be applied not only to direct-type surface light-emitting devices but also to edge-type surface light-emitting devices 22.

[0119] The embodiments of the present disclosure are not limited to the above-described embodiments, and various modifications are possible within the scope of the gist of the technology of the present disclosure.

[0120] The effects described in this specification are merely examples and are not intended to be limiting, and there may be effects other than those described in this specification.

[0121] The technology disclosed herein may employ the following configurations. (1) A surface emitting device comprising: a light-emitting unit including a first light source that emits a first color and a second light source that emits a second color; and a light-emitting control unit that controls the first light source and the second light source to have different lighting timings. (2) The surface emitting device described in (1), wherein the first color and the second color are blue, green, or red, and a third color among the blue, green, and red colors other than the first color and the second color is emitted in response to light from the first light source. (3) The surface emitting device described in any of (1) to (2), wherein the light-emitting unit includes the first light source that emits blue light, which is the first color, the second light source that emits green light, which is the second color, and a wavelength converting material that emits red light, which is a third color, in response to light of the first color. (4) The surface emitting device described in (3), wherein the light-emitting unit includes the first light source, the second light source, and a sheet containing the wavelength converting material. (5) The surface emitting device according to (4), wherein the light emitting section has a reflective sheet below or above the sheet containing the wavelength converting material. (6) The surface emitting device according to (3), wherein the light emitting section has a housing section that houses the first light source, the second light source, and a resin material containing the wavelength converting material. (7) The surface emitting device according to (3), wherein the light emitting section has a first housing section that houses the first light source and a first resin material, and a second housing section that houses the second light source and a second resin material, wherein the first resin material contains the wavelength converting material, and the second resin material does not contain the wavelength converting material. (8) The surface emitting device according to any of (1) to (3), (6), and (7), wherein the light emitting section has a lens having a protruding shape. (9) The surface emitting device according to any of (3) to (8), wherein the wavelength converting material contains at least one of a fluoride phosphor and a quantum dot. (10) The surface emitting device according to any one of (3) to (9), wherein the blue light emitted by the first light source has a peak wavelength of 450 nm or more. (11) The surface emitting device according to any one of (1) to (10), wherein the light emission control unit controls the first light source and the second light source so that the light emission periods of the first light source and the second light source do not overlap.(12) The surface emitting device according to any one of (1) to (11), wherein the light emission control unit provides a first waiting time between the end of lighting of the first light source and the start of lighting of the second light source, and the second waiting time between the end of lighting of the second light source and the start of lighting of the first light source is shorter than the first waiting time. (13) The surface emitting device according to any one of (1) to (12), wherein the light emission control unit controls the first light source and the second light source to have different lighting start timings. (14) The surface emitting device according to any one of (1) to (13), wherein the light emission control unit controls the first light source and the second light source to have different lighting times per pulse. (15) The surface emitting device according to any one of (1) to (14), wherein the light emission control unit controls the first light source and the second light source to have different lighting end timings. (16) The surface emitting device according to any one of (1) to (15), wherein the light-emission control unit controls the current values ​​supplied to the first light source and the second light source to be different. (17) The surface emitting device according to any one of (1) to (16), wherein the light-emitting area is composed of a plurality of divided areas, and the light-emission control unit controls the light-emission brightness of the light-emitting unit for each divided area. (18) The surface emitting device according to any one of (1) to (17), wherein the surface emitting device is an edge type. (19) A liquid crystal display device comprising: a surface emitting device comprising: a light-emitting unit including a first light source that emits a first color and a second light source that emits a second color; and a light-emission control unit that controls the lighting timings of the first light source and the second light source to be different. (20) A television receiver comprising: a surface emitting device comprising: a light-emitting unit including a first light source that emits a first color and a second light source that emits a second color; and a light-emission control unit that controls the lighting timings of the first light source and the second light source to be different.

[0122] REFERENCE SIGNS LIST 1 Liquid crystal display device, 11 Input unit, 12 Tuner, 13 Display module, 21 Signal processing unit, 22 Surface light emitting device, 23 Liquid crystal control unit, 24 Liquid crystal panel, 31 Light emission control unit, 32 Light emitting panel, 51 Bezel, 52 (52A, 52B) Optical sheet, 52P, 52P' Diffuser, 52Q Fluorescent light emitting sheet, 52X Reflective sheet, 53 Back chassis, 54 Control board, 61 Circuit board, 62 Reflective sheet, 63 Light emitting unit, 101 Blue LED, 102 Green LED, 103 Package, 104 Resin material, 105 Phosphor, 106 Lens

Claims

1. A surface light emitting device comprising: a light emitting unit including a first light source that emits light of a first color and a second light source that emits light of a second color; and a light emission control unit that controls the lighting timing of the first light source and the second light source to be different.

2. The surface emitting device according to claim 1, wherein the first color and the second color are either blue, green, or red, and a third color among blue, green, and red other than the first color and the second color is emitted in response to light from the first light source.

3. The surface emitting device according to claim 1, wherein the light emitting section includes the first light source that emits blue light, which is the first color, the second light source that emits green light, which is the second color, and a wavelength conversion material that emits red light, which is a third color, in response to light of the first color.

4. The surface emitting device according to claim 3, wherein the light emitting section comprises the first light source, the second light source, and a sheet containing the wavelength conversion material.

5. The surface emitting device according to claim 4, wherein the light emitting section has a reflective sheet below or above the sheet containing the wavelength conversion material.

6. The surface emitting device according to claim 3, wherein the light emitting section has a housing section that houses the first light source, the second light source, and a resin material containing the wavelength conversion substance.

7. The surface emitting device according to claim 3, wherein the light emitting section has a first housing section that houses the first light source and a first resin material, and a second housing section that houses the second light source and a second resin material, the first resin material contains the wavelength conversion substance, and the second resin material does not contain the wavelength conversion substance.

8. The surface emitting device according to claim 1, wherein the light emitting section has a lens having a protruding shape.

9. The surface emitting device according to claim 3, wherein the wavelength conversion material includes at least one of a fluoride phosphor and a quantum dot.

10. The surface emitting device according to claim 3, wherein the blue light emitted by the first light source has a peak wavelength of 450 nm or more.

11. The surface light emitting device according to claim 1, wherein the light emission control unit controls the first light source and the second light source so that the light emission periods do not overlap.

12. The surface emitting device according to claim 1, wherein the light emission control unit provides a first waiting time between the end of lighting of the first light source and the start of lighting of the second light source, and a second waiting time between the end of lighting of the second light source and the start of lighting of the first light source is shorter than the first waiting time.

13. The surface light emitting device according to claim 1, wherein the light emission control unit controls the first light source and the second light source so that their lighting start timings differ.

14. The surface light emitting device according to claim 1, wherein the light emission control section controls the first light source and the second light source so that the lighting times of one pulse are different from each other.

15. The surface light emitting device according to claim 1, wherein the light emission control unit controls the first light source and the second light source so that their lighting end timings differ.

16. The surface light emitting device according to claim 1, wherein the light emission control unit controls the current values ​​supplied to the first light source and the second light source to be different from each other.

17. The surface light emitting device according to claim 1, wherein the light emitting area is composed of a plurality of divided areas, and the light emission control unit controls the light emission brightness of the light emitting unit for each divided area.

18. The surface emitting device according to claim 1, which is an edge type.

19. A liquid crystal display device comprising a surface emitting device comprising: a light emitting unit including a first light source that emits light of a first color and a second light source that emits light of a second color; and a light emission control unit that controls the first light source and the second light source so that their lighting timings differ.

20. A television receiver comprising a surface light-emitting device comprising: a light-emitting unit including a first light source that emits light of a first color and a second light source that emits light of a second color; and a light-emitting control unit that controls the first light source and the second light source so that their lighting timings differ.

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