KR20160069469A - Display device, driving method of display device - Google Patents

Abstract

According to the embodiment, power consumption can be suppressed as a whole without significantly lowering the transmission efficiency. According to the embodiment, a plurality of sub-pixels PX arranged in a first direction X and a second direction Y crossing the first direction X and a color filter corresponding to each sub-pixel PX , And a lighting device (LU). At least the blue filter (B) and the yellow filter (Y) are adjacent to each other in the color filter, and the period during which at least cyan light is output and the magenta light is output within one frame period Period.

Description

DISPLAY DEVICE, DRIVING METHOD OF DISPLAY DEVICE,

The present application claims the priority of the prior Japanese Patent Application No. 2014-247904 (filed on December 8, 2014) and Japanese Patent Application No. 2015-222143 (filed November 12, 2015) The entire disclosure is hereby incorporated by reference.

The present embodiment relates to a display device and a driving method of the display device.

Recently, portable terminals have been spreading. 2. Description of the Related Art A portable terminal includes a smart phone, a personal digital assistant device (PDA), a tablet computer, and the like. These portable terminals can display a color image.

As a technique for displaying a color image, there is a field sequential color (FSC) scheme. The FSC method uses a red (R) light emitting device, a green (G) light emitting device and a blue (B) light emitting device as illumination devices in the past. The FSC method is a method in which one frame period is divided into three periods (three periods) as a light emitting period of a red (R) light emitting device, a light emitting period of a green (G) light emitting device, Quot; field "). The selected pixel (selected R pixel) for red display, the pixel selected for blue display (selected B pixel), the pixel selected for green display (selected G Pixel) is driven. A point light source may also be used as the light emitting device. More specifically, a light emitting diode (LED) may be used as the point light source.

The selected R pixel, the selected B pixel, and the selected G pixel are pixels selected from the plurality of pixels arranged two-dimensionally on the liquid crystal display panel, corresponding to the R, G, and B signals. Each liquid crystal display image by the selected R pixel, the selected B pixel, and the selected G pixel is displayed in an independent period, but a color image is visible to a person due to the afterimage effect of the eye. The above-mentioned FSC method does not require a color filter in the liquid crystal display panel, and thus the utilization rate of light is high.

1 is an exploded perspective view schematically showing a configuration example of a liquid crystal display (LCD) in this embodiment.
Fig. 2 schematically shows a configuration of the liquid crystal display panel PNL and an equivalent circuit. Fig.
3A is a diagram showing an example of arrangement of color filters of sub pixels and an example of colors of illumination devices;
Fig. 3B is a diagram showing the relationship between the cyan and magenta fields within one frame period of the illumination apparatus, which are output from the color filters; Fig.
3C is a diagram showing an example of the intensity of the color of light emitted from the color filter with respect to the cyan field and the magenta field of the illumination device;
4A is a diagram showing another example of the arrangement of color filters of sub-pixels and the color of a lighting device.
Fig. 4B is a diagram showing the relationship between the cyan, white, and magenta fields within one frame period of the illumination apparatus, which are output from the color filters; Fig.
4C is a diagram showing an example of the intensity of a luminescent color output from a color filter for a cyan field, a white field and a magenta field of a lighting apparatus;
5 is a graph showing the transmittance of the blue filter and the yellow filter and the luminous energy of the blue (B) LED, the green (G) phosphor and the red (R) phosphor.
FIG. 6 is a diagram showing the aperture ratio and transmittance of sub-pixels having a yellow filter and the sub-pixels having a blue filter in the embodiment and the numerical aperture and transmittance of sub-pixels without a filter.
7A is a graph showing the relationship between luminance and current of LEDs of R, LEDs of G and B, and the result of multiplication of luminance and current as 100. In FIG. 7A, phosphor LEDs (white LEDs Element] and the result of multiplication is defined as an LED effect.
FIG. 7B is a diagram showing the aperture ratio, transmittance, and LED effect of the embodiment of the present invention in comparison with the aperture ratio, the transmittance, and the LED effect in the conventional field sequencing method.
8A is an explanatory diagram showing a distance at which the color changes on the chromaticity diagram when the display color changes in the area including the primary colors R, G,
8B is an explanatory diagram showing a distance at which the color changes on the chromaticity diagram when the display color changes in an area of cyan and magenta;
9A is a time chart showing an operation in the case where the illumination device has a light emission field of white (W) in addition to a light emission field of cyan and a light emission field of magenta.
Fig. 9B is another embodiment, and shows an operation in the case where the illuminating device has a light-emitting field of white (W) in addition to the light-emitting field of cyan and the light-emitting field of magenta, and the filter also has yellow, blue and white Represents a time chart.
10A is a view showing an embodiment in which the filter includes white (W), yellow (Y), and blue (B).
FIG. 10B is a diagram showing an example of a pixel circuit corresponding to the filter of FIG. 10A; FIG.
11A is a diagram showing another embodiment in which the filter includes white (W), yellow (Y), and blue (B).
Fig. 11B is a diagram showing an example of a pixel circuit corresponding to the filter of Fig. 11A; Fig.
11C is a diagram showing another example of the pixel circuit corresponding to the filter of FIG. 11A; FIG.
12A is a diagram showing another embodiment in which the filter includes white (W), yellow (Y), and blue (B).
12B is a diagram showing an example of a pixel circuit corresponding to the filter of Fig. 12A; Fig.
12C is a diagram showing another example of the pixel circuit corresponding to the filter of Fig. 12A; Fig.
13 is a diagram showing an example of a graph of spectral transmittance of a yellow filter and a blue filter.
14 is an explanatory view showing an example of calculation of an area ratio of a yellow filter and a blue filter;
Fig. 15 is a diagram showing an example of characteristics of spectral luminances when the magenta LED and the cyan LED of the illumination device are simultaneously emitted; Fig.
16 is a graph showing the relationship between the transmittance ratio of the blue filter and the yellow filter and the ratio of transmittance of the blue filter and the yellow filter to that of the illuminator of magenta and cyan And a luminance ratio in a graph.

Hereinafter, various embodiments will be described in detail with reference to the accompanying drawings.

First, the introduction of the embodiment to be described below will be described. The FSC method does not require a color filter in the liquid crystal display panel, and thus the utilization rate of light is high. However, the luminous efficiency of the green (G) LED is about 1/3 of the luminous efficiency of the blue (B) LED. When the supply voltage is increased to raise the luminous efficiency of the green (G) LED, the power consumption is increased. In addition, in the case of a red (R) LED, the wavelength associated with chromaticity tends to change over time. In order to maintain the white region on the chromaticity diagram, G) LED, and the blue (B) LED must also be adjusted. However, this adjustment entails technical difficulties.

Further, there is also a problem that color break-up (CBU) is apt to occur and image quality deterioration is accompanied. In this color break-up CBU, for example, a plate having a stripe-shaped window is arranged on the display surface of a liquid crystal display panel displaying the colors of R, G, and B in the form of stripes in a field sequential manner, Refers to a phenomenon in which a stripe of a small width of color is left as a residual image when viewed on the screen from the window side of the plate when the plate is vibrated in the direction crossing the stripe. Originally, it is preferable that the display surface is whitened. For example, when a black and white stripe is displayed in a field sequential manner and a line of sight is rapidly moved, the end of the stripe of black and white refers to a phenomenon in which water is seen.

In order to improve such color break-up (CBU), improvement is seen when one frame period is set to four fields as a whole by adding a field of white (W) to three fields of RGB (also called three subframes) . However, in order to set the frame to four fields, it is necessary to raise the field period of the drive circuit of the LED from three times to four times the frame period. Therefore, the power consumption for driving is increased.

Therefore, it is an object of the present invention to provide a display device and a method of driving the display device which can suppress power consumption as a whole without significantly lowering the transmission efficiency.

Hereinafter, a specific embodiment will be described. According to the embodiment, the display device has a plurality of sub-pixels arranged in a first direction and a second direction crossing the first direction, a color filter corresponding to each sub-pixel, and an illumination device . The color filter has at least a blue filter and a yellow filter adjacent to each other. The illumination device has a light source having at least a period during which cyan light is output and a period during which magenta light is output within one frame period.

It is to be understood that the disclosure is merely illustrative and that those skilled in the art will readily be able to overcome the problem of timely changes while keeping the invention in mind, as a matter of course included in the scope of the present invention. In the drawings, the width, thickness, shape, and the like of each part are schematically shown in order to clarify the explanation, but the interpretation of the present invention is not limited thereto. In the present specification and the drawings, constituent elements which exhibit the same or similar functions as those described above with respect to the drawings already described are denoted by the same reference numerals, and duplicate detailed explanations may be omitted.

Fig. 1 is an exploded perspective view schematically showing a configuration example of a liquid crystal display (LCD) in the present embodiment. A liquid crystal display (LCD) is a liquid crystal display device that includes an active matrix liquid crystal display panel PNL, a double-sided tape TP, an optical sheet OS, a frame FR, a light guide plate LG, a light source unit LU, RS, a bezel BZ, and the like. The surface light source device LS is a lighting device that allows light to enter the liquid crystal display panel PNL. The surface light source device LS is constituted by at least a light guide plate LG and a light source unit LU.

The liquid crystal display panel PNL includes a first substrate SUB1 in the form of a flat plate, a second substrate SUB2 in the form of a flat plate opposed to the first substrate SUB1, a first substrate SUB2, And a liquid crystal layer held between the pixel electrodes SUB1 and SUB2. Since the liquid crystal layer is extremely thin compared to the thickness of the liquid crystal display panel PNL and is located inside the sealing member for bonding the first substrate SUB1 and the second substrate SUB2, the illustration is omitted.

The liquid crystal display panel PNL includes a display area DA for displaying an image in an area where the first substrate SUB1 and the second substrate SUB2 face each other. In the illustrated example, the display area DA is formed in a rectangular shape and may be referred to as an active area. The liquid crystal display panel PNL is a transmissive liquid crystal display panel having a transmissive display function for selectively transmitting light from the surface light source device LS to display an image. The liquid crystal display panel PNL may have a configuration corresponding to a transverse electric field mode using a transversal electric field substantially parallel to the main surface of the substrate as a display mode, It may have a corresponding configuration.

In the illustrated example, the driving IC chip CP and the flexible printed circuit board (FPC) are mounted on the first substrate SUB1 as a signal supply source for supplying signals necessary for driving the liquid crystal display panel PNL.

The optical sheet OS has optical transparency and is located on the back side of the liquid crystal display panel PNL and faces at least the display area DA. The optical sheet OS includes a diffusion sheet OSA, a prism sheet OSB, a prism sheet OSC, a diffusion sheet OSD, and the like. In the illustrated example, all of these optical sheets OS are formed in a rectangular shape. Further, the number of diffusion sheets or prism sheets included in the optical sheet OS, the configuration of lamination, and the like are merely examples, and the present invention is not limited to the example shown in Fig.

The frame FR is positioned between the liquid crystal display panel PNL and the bezel BZ. In the illustrated example, the frame FR is formed in a rectangular frame shape and has a rectangular opening portion OP opposed to the display area DA. The shape of the frame FR is an example, and is not limited to the example shown in Fig. If the frame FR is not required, it is not necessary to install the frame FR.

The double-sided tape TP is positioned between the liquid crystal display panel PNL and the frame FR outside the display area DA. The double-sided tape TP has, for example, light shielding property and is formed in a rectangular frame shape. Further, if the display panel PNL and the frame FR can be fixed without using the double-sided tape TP, the double-sided tape TP may not be provided.

The light guide plate LG is positioned between the frame FR and the bezel BZ. The light guide plate LG is formed in a flat plate shape and has a first major surface LGA, a second major surface LGB on the opposite side to the first major surface LGA, and a first major surface LGA and a second major surface LGB, (LGC) that connects the light sources.

The light source unit LU is disposed along the side LGC of the light guide plate LG. The light source unit LU includes a plurality of light emitting diodes (LEDs) each functioning as a light source, a flexible circuit board (LFPC) on which a plurality of light emitting diodes (LEDs) are mounted, and the like. In the illustrated example, these light emitting diodes (LEDs) are arranged in a line along a side LGC parallel to short sides of the light guide plate LG. The light emitting diodes (LEDs) may be arranged along the other side (the side intersecting the side LGC) parallel to the long side of the light guide plate LG. That is, although the light emitting diodes (LEDs) are arranged in the first direction X in Fig. 1, they may be arranged in the second direction Y intersecting with them. The light emitting diodes (LEDs) are driven in a field sequential manner as will be described later in detail.

The reflective sheet RS has light reflectivity and is located between the bezel BZ and the light guide plate LG. In the illustrated example, the reflection sheet RS is formed in a rectangular shape.

The bezel BZ accommodates the liquid crystal display panel PNL, the double-sided tape TP, the optical sheet OS, the frame FR, the light guide plate LG, the light source unit LU, . In the illustrated example, the surface light source device LS is disposed on the rear surface side of the liquid crystal display panel PNL, that is, on the side facing the first substrate SUB1, and the illuminating device (so-called backlight in this case) .

2 schematically shows an example of the configuration of the liquid crystal display panel (PNL) and an equivalent circuit. The display device is provided with an active matrix type liquid crystal display panel (PNL). The liquid crystal display panel PNL includes a first substrate SUB1, a second substrate SUB2 disposed opposite to the first substrate SUB1, and a second substrate SUB2 disposed between the first substrate SUB1 and the second substrate SUB2. And a supported liquid crystal layer LQ. The display area DA corresponds to a region in which the liquid crystal layer LQ is held between the first substrate SUB1 and the second substrate SUB2 and has a rectangular shape and a plurality of Sub-pixel. Thus, each sub-pixel is arranged in the vicinity of each intersection where the gate wiring in the first direction X intersects with the source wiring in the second direction Y, and the sub-pixel signal is selectively supplied to each of the plurality of sub- A driving circuit is provided.

In this specification, one sub-pixel means a structure in which one pixel circuit and one color filter are integrated. Therefore, in the case of one sub-pixel, one color filter is provided to express a single color. A minimum unit in which a plurality of sub-pixels having different color filters are aggregated for a sub-pixel and in which various colors of primary colors to intermediate colors can be expressed is simply referred to as a pixel or a composite pixel. As a combination of sub-pixels, a combination of sub-pixels having red, green and blue filters, a combination of sub-pixels having yellow and blue filters, and a combination of sub-pixels having yellow, blue and white filters A combination of sub-pixels, and the like.

The first substrate SUB1 includes a plurality of gate lines G (G1 to Gn) extending along a first direction X (also referred to as a row direction or a horizontal direction) in the display area DA, And a plurality of source wirings S (S1 to Sm) extending along a second direction Y (also referred to as a column direction or a longitudinal direction) intersecting the direction X.

Each of the sub-pixels includes a switching element SW electrically connected to the gate wiring G and the source wiring S as shown on the right side of FIG. 2 A pixel electrode PE electrically connected to the switching element SW in the sub-pixel, a common electrode CE1 opposed to the pixel electrode PE, and the like. Although two common electrodes CE1 are shown, they are actually integrated electrodes. The storage capacitor CS is formed, for example, between the common electrode CE1 and the pixel electrode PE. The second substrate SUB2 faces the first substrate SUB1 through the liquid crystal layer LQ. The storage capacitor CS may or may not be formed as needed. For example, when the liquid crystal display (LCD) is in the FFS (Fringe Field Switching) mode, the pixel electrode PE, the common electrode CE1, and the insulating material disposed therebetween function as the storage capacitor CS , It is not necessary to separately form the storage capacitor CS.

Each of the gate wirings G (G1 to Gn) is drawn out of the display area DA and connected to the first drive circuit GD. Each of the source wirings S (S1 to Sm) is drawn out of the display area DA and connected to the second drive circuit SD. The first driving circuit GD and the second driving circuit SD are formed at least partially on the first substrate SUB1 and are connected to the driving IC chip (liquid crystal driver, (CP).

In order to realize the column inversion driving method, the second driving circuit SD can output pixel signals having different polarities when outputting the pixel signal to the source wiring of the adjacent column. The driving IC chip CP includes a controller for controlling the first driving circuit GD and the second driving circuit SD and functions as a signal supply source for supplying signals necessary for driving the liquid crystal display panel PNL do. In the illustrated example, the driving IC chip CP is mounted on the first substrate SUB1 outside the display area DA of the liquid crystal display panel LPN.

The common electrode CE1 extends all over the display area DA and is formed in common to a plurality of sub-pixels. The common electrode CE1 is drawn out to the outside of the display area DA and connected to the power feeding part Vcom. The power supply portion Vcom is formed on the first substrate SUB1 outside the display area DA, for example, and is electrically connected to the common electrode CE1. A constant common voltage is supplied to the power feeding portion Vcom.

In the plurality of sub-pixels, color filters are arranged in a predetermined rule. The color filter is formed on the second substrate SUB2, facing the pixel electrode with the liquid crystal layer LQ therebetween.

The plurality of sub-pixels may include, for example, a first column, a second column, a third column, And the color filter in the first column is blue (B) and the color filter in the second column is yellow (Y), and this color is repeated in the first direction X. When the width H1 of the blue filter and the width H2 of the yellow filter are compared, the width of the yellow filter is formed wider than the blue filter.

3A shows an example of arrangement of color filters of each sub pixel and an example of colors of the illumination device. 3A, the structure of the source wiring S (S1 to Sm) on the first substrate SUB1 side is omitted for easy understanding of the arrangement of the color filters.

A blue filter (width H1) and a yellow filter (width H2) are repeatedly arranged in the first direction X (the horizontal direction in the figure). The color filter is formed on the second substrate SUB2. In this display device, the surface light source device, that is, the illumination device is driven in a field sequential manner. Here, the plurality of light emitting diodes (LEDs) of the lighting apparatus include light emitting diodes of cyan and magenta. The plurality of light emitting diodes (LEDs) are mounted on a flexible circuit board (LFPC).

The cyan light-emitting diode can be realized by, for example, laminating a green phosphor to a blue light-emitting diode. The magenta light emitting diode can be realized by, for example, laminating a red phosphor to a blue light emitting diode. The cyan light emitting diode is turned on (turned on) in the half period of the first half of one frame, for example, and turned off (turned off) in the half period of the latter half. On the other hand, the magenta light emitting diode is driven so as to be turned off (turned off) in the first half period of one frame and turned on (lit) in the second half period.

The light emitting diodes (LEDs) are arranged in a line parallel to the short sides of the light guide plate. The light emitted from the light emitting diode (LED) is incident on the light guide plate. As a result, the surface light emission (the light periodically repeating cyan and magenta) emitted from the light guide plate passes through the pixels in the light transmitting state. Here, since the driving method is the field sequential method, the surface light emission becomes light in which cyan and magenta are periodically repeated.

FIG. 3B shows the relationship between the fields of cyan and magenta, which are luminescent colors of the illumination device, and the colors of light emitted from the color filters. The illumination apparatus has a cyan field (1/2 frame) and a magenta field (1/2 frame) in one frame period. The colors that can be displayed on the display surface of the display device in the cyan field (1/2 frame) are blue (B) and green (G). On the other hand, the colors that can be displayed on the display surface of the display device in the magenta field (1/2 frame) are blue (B) and red (R).

As can be seen from FIG. 3B, the blue (B) can be displayed in either a cyan field or a magenta field. On the other hand, green (G) can be displayed only in the cyan field, and red (R) can be displayed only in the magenta field. As a result, the output level (light emission intensity) of blue (B) tends to become stronger than that of green (G) and red (R).

In order to solve such unbalance, in this apparatus, as shown in, for example, Figs. 3A and 3C, a device is designed so as to obtain a light emission intensity balanced with the light emission colors of blue (B), green (G), and red .

That is, the width H1 of the blue filter is made smaller than the width H2 of the yellow filter so that the area of the blue filter becomes smaller than the area of the yellow filter. 3C, the light emission intensity of blue (B), the light emission intensity of green (G), and the light emission intensity of red (R) are designed to be substantially equal in one frame period.

In order to obtain white balance, the emission intensity of blue (B), the emission intensity of green (G), and the emission intensity of red (R) are not necessarily equal. It is preferable that the light emission intensities of blue (B), green (G) and red (R) are set after taking into consideration the characteristics (transmittance and the like) of each color filter in order to obtain the position of white on the chromaticity diagram.

In the above-described embodiment, one frame includes two fields of a cyan field and a magenta field, but the present invention is not limited thereto.

In Figs. 4A, 4B and 4C, one frame includes three fields of a cyan field, a magenta field and a white field. Therefore, as shown in FIG. 4A, the plurality of light emitting diodes (LEDs) constituting the lighting apparatus include light emitting diodes of cyan, white and magenta.

The light source unit (LU) having a plurality of light emitting diodes (LEDs) shown in Figs. 3A and 4A is disposed on the end face side of the light guide plate in the first direction X. However, the arrangement position of the light source unit (LU) is not limited. The light source unit (LU) may be disposed on the end face of the light guide plate in the second direction Y. The light source unit (LU) shown in FIG. 4A can provide a cyan field, a white field, and a magenta field. Although FIG. 4A shows a white light emitting diode, the light source unit LU does not necessarily have a white light emitting diode. This is because the white field can be provided by simultaneously lighting the cyan and magenta light emitting diodes as shown in Figs. 9A and 9B which will be described later.

4B shows a time sequence in which one frame period is divided into a cyan field, a white field, and a magenta field. The relationship between the fields of cyan, white and magenta, which are luminescent colors of the illumination device, and the color of light emitted from the color filter are shown. The illumination device has a cyan field (1/3 frame), a white field (1/3 frame) and a magenta field (1/3 frame) in one frame period. The colors that can be displayed on the display surface of the display device in the cyan field (1/3 frame) are blue (B) and green (G). The colors that can be displayed on the display surface of the display device in the white field (1/3 frame) are blue (B), green (G), and red (R), and eventually white (W) can be displayed. The colors that can be displayed on the display surface of the display device in the magenta field (1/3 frame) are blue (B) and red (R).

FIG. 4C shows a state in which the light emission fields of white (W = R, G, B) are increased in addition to the cyan field and the magenta field in one frame period shown in FIG. 3C. In this embodiment, since one frame is divided into three fields, the switching frequency of the lighting apparatus is increased as compared with the case where one frame of the above-described embodiment is divided into two fields. However, in the case of the conventional device having the W field, there are four fields of R, G, B and W fields, and the field of this embodiment is smaller than that of the conventional device by one field. Therefore, even if the W field is increased, the power consumption amount of the present embodiment does not increase as compared with the conventional device.

5 shows the transmittance of the blue filter and the yellow filter according to wavelengths. And the emission curves of the blue (B) LED, the green (G) phosphor, and the red (R) phosphor change depending on the wavelength. The characteristic curve showing the transmittance of the blue filter and the characteristic curve of the light emission energy of the LED of blue (B) almost coincide with each other. The green light in the vicinity of 540 nm to 550 nm passes through the yellow filter as the luminous energy of the phosphor of green (G). The light emission energy of the red (R) phosphor is such that red light in the vicinity of 630 nm to 650 nm passes through the yellow filter.

FIG. 6 is a diagram showing the aperture ratio and transmittance of a pixel having a yellow filter and the sub-pixel having a blue filter in the embodiment, and the aperture ratio and transmittance of sub-pixels without a filter. The aperture ratio of the sub-pixel without filter is 78.8% and the transmittance is 25.3%. On the contrary, the aperture ratio of the sub pixel having the yellow filter of the embodiment is 67.0%, the transmittance is 13.0%, the aperture ratio of the sub pixel having blue filter is 57.8%, and the transmittance is 0.34%.

Figure 7A shows the elements that are referenced to obtain LED effects. 7A shows the respective luminances (1.7 candelas) and current (30 mA) of the red (R) LED, the green (G) LED and the blue (B) LED. This figure shows that the LED requires a current of 30 mA to obtain light emission of 1.7 candelas. The LED effect is obtained from this value. That is, the LED effect is the luminance level for the current. For example, {(1.7) / 30} = 0.056 is obtained. The LED effect 0.056 is defined as 100.

7A shows a luminance (2.7 candela) and a current (20 mA) of a phosphor LED (a device in which a phosphor is stacked on a light emitting LED of a predetermined color to output cyan or magenta light). This figure shows that the phosphor LED requires 20 mA current to obtain 2.7 candelas. From this value, the LED effect {(2.7) / 20} = 0.135 can be obtained. Then, the relative value 251 from the above LED effect 0.056 = 100 is obtained.

Cyan light emission can be obtained by combining a green (G) light emitting phosphor with an LED that emits blue (B) light. Further, magenta light emission can be obtained by combining red (R) light emission phosphors with LEDs that emit blue (B) light.

In Fig. 7A, a value including a duty loss is also shown. The duty loss is a value derived from an experimental result that when the field sequential driving is performed, the LED effect is reduced by about 10%.

Therefore, the LED effect 100 becomes the LED effect 90 in consideration of the duty loss, and the LED effect 251 becomes the LED effect 226 in consideration of the duty loss.

FIG. 7B is a diagram showing the aperture ratio, transmittance, and LED effect in the conventional field sequencing system in comparison with the aperture ratio, transmittance, and LED effect of the embodiment of the present invention. The RGB field sequential method realized by the time-division light emission of R LED, G LED and B LED without filter is 78.8% in aperture ratio, 25.3% in transmittance and 90% in LED effect.

On the contrary, in the first field sequential system realized by the blue filter and the yellow filter and the backlight with the luminescent color of cyan and magenta, the aperture ratio (B = 57.8%, Y = 67.8%), the transmittance 13.3%, and the LED effect 226 , And the area ratio of the B filter and the Y filter is 1: 2). (B = 49.9%, Y = 73.0%), a transmittance of 16.1%, and an LED effect of 226 in the second field sequential system in which the light emission colors of the blue filter and the yellow filter and the illumination device are realized by cyan and magenta , And the area ratio of the B filter and the Y filter is 1: 3).

Here, by multiplying the transmittance a by the LED effect b, and setting the power efficiency of the lighting apparatus,

The RGB field sequential method described above ... 22.8

The first field sequential scheme described above ... 30.1

The second field sequential scheme described above ... 36.4

. As a result, it can be seen that the lighting apparatus of the embodiment of the present invention has excellent power efficiency.

Fig. 8A shows the distance where the color changes on the chromaticity diagram when the display color changes in the area including the primary colors R, G, and B by the arrows. Fig. 8B shows the distance where the color changes on the chromaticity diagram when the display color changes in the cyan and magenta areas. As can be seen from the comparison of the two, the display color is shorter than the distance when the display color changes in the areas of cyan and magenta in the area including the primary colors R, G and B. This means that the difference in chromaticity is small when the display color is changed. Thereby, the color break-up (CBU) is reduced.

9A is a time chart showing an operation in the case where the illumination device has a light emission field of white (W) in addition to a light emission field of cyan and a light emission field of magenta. To obtain a light emission field of white (W), a cyan phosphor LED and a magenta phosphor LED are simultaneously lit. Therefore, a white (W) light emitting diode as shown in Fig. 4A is not required. This lighting control is executed by a lighting device control circuit (also referred to as a backlight control circuit) in a driving IC chip CP (shown in Fig. 2) that drives the LCD, though it is not shown.

As a result, in the cyan light-emitting field, a color representation of a color intermediate between green and blue and between green and blue is possible, and in the magenta light emission field, a color representation of red and blue and a color intermediate between red and blue is possible . In the light emission field of white (W), a color representation of red, green, and blue (that is, white (W)) is possible.

Fig. 9B is another embodiment. In the embodiment of Fig. 9A, a yellow filter and a blue filter are used as the color filters. However, in the embodiment of Fig. 9B, a yellow filter, a blue filter, and a white (W) filter are used as the color filters. The light emission procedure of the lighting apparatus is the same as that in Fig. 9A. That is, the illumination device has a light emission field of white (W) in addition to a light emission field of cyan and a light emission field of magenta.

In the cyan light emitting field, blue, green, and intermediate colors can be expressed. In the magenta light emitting field, blue, red, and intermediate colors can be expressed. In the light emission field of white (W), red, green, and blue (that is, white (W)) can be expressed.

10A is a diagram showing an embodiment in which the filter includes white (W), yellow (Y), and blue (B). In this embodiment, the areas of the filters of white (W), yellow (Y), and blue (B) are formed equally. Sub-pixels correspond to filters of white (W), yellow (Y), and blue (B), respectively. The integration of the filters of white (W), yellow (Y), and blue (B) and each sub-pixel can be referred to as one pixel (or unit pixel). Any color of RGB can be expressed by this pixel, and the sub-pixel is for forming a pixel. The shape of this pixel (synthesis filter of white (W), yellow (Y), and blue (B)) is, for example, square in the plan view.

10B is a diagram showing an example of a pixel circuit corresponding to the filter of FIG. 10A. Each of the pixel circuits forming each sub-pixel has been described with reference to Fig. That is, each pixel circuit of each sub-pixel has a switch element. The switch element is composed of, for example, a thin film transistor (TFT), a gate is connected to the gate line G, And the drain is connected to the pixel electrode for driving the liquid crystal of the liquid crystal layer.

11A is a view showing another embodiment in which the filter includes white (W), yellow (Y), and blue (B). In this embodiment, each of the areas of the yellow (Y) filter and the white (W) filter is formed larger than the area of the blue (B) filter.

Fig. 11B is a diagram showing an example of the pixel circuit corresponding to the filter of Fig. 11A. Each of the pixel circuits forming each sub-pixel has been described with reference to Fig. When viewed in the column direction (second direction Y), the blue (B) sub-pixels are arranged continuously. However, when the sub-pixels of yellow (Y) and the sub-pixels of white (W) are viewed in the column direction (second direction Y), they are alternately arranged. Further, the sub-pixels of yellow (Y) and the sub-pixels of white (W) are arranged alternately even when viewed in the row direction (first direction X). Also in this embodiment, the plane shape of the pixel (unit pixel) is square. In the configuration of Fig. 11B, one blue (B) filter is assigned to each of the filters of one yellow (Y) filter and one white (W) filter. That is, in the configuration of Fig. 11B, one blue (B) filter is arranged in one pixel.

11C is a diagram showing another example of the pixel circuit corresponding to the filter of FIG. 11A. The difference between the pixel circuit shown in Fig. 11B and the pixel circuit shown in Fig. 11C is that blue (B) sub-pixels are formed over two rows. That is, the source and gate of the switching element of the blue (B) sub-pixel are connected to the gate wiring G1 and the source wiring S1, respectively, and the pixel electrode including the sub-pixel and the blue ) Are formed extending from the first row to the second row. Thus, one blue (B) filter is shared for one yellow (Y) filter and one white (W) filter. That is, in the configuration of Fig. 1C, one blue (B) filter is arranged over a plurality of pixels.

12A is a diagram showing another embodiment in which the filter includes white (W), yellow (Y), and blue (B). In this embodiment, a sub-pixel of yellow (Y) and a sub-pixel of white (W) are repeatedly arranged in the row direction (first direction X) of the first row, Sub pixels of blue (B) and blue (B) have a length of two sub pixels of white (W) and yellow (Y). For example, in Fig. 12B showing an example of the pixel circuit corresponding to the filter of Fig. 12A, the source and gate of the switching element of the blue (B) sub-pixel with respect to the gate wiring G2 and the source wiring S1 are A pixel electrode including a sub pixel and a blue (B) filter are formed extending from the first column to the second column together with the switching element. Also in this embodiment, the plane shape of the pixel (unit pixel) is square.

12C is a diagram showing another example of the pixel circuit corresponding to the filter of FIG. 12A. The difference between the pixel circuit shown in Fig. 12B and the pixel circuit shown in Fig. 12C will be described. The sub-pixels of blue (B) in FIG. 12B are formed over two columns, but sub-pixels of blue (B) shown in FIG. 12C are formed in each column.

13 is a diagram showing an example of a curve of spectral transmittance of a blue (B) filter and a yellow (Y) filter. The blue (B) filter is easy to transmit light having a wavelength in the vicinity of 450 nm (this transmittance is, for example, Tb). The filter of yellow (Y) is likely to transmit wavelength light in the vicinity of 580 nm (this transmittance is, for example, Ty).

Fig. 14 is an explanatory view showing an example of calculation of the area ratio of the blue (B) filter to the yellow (Y) filter for the pixel. For example, the width a of the filter of yellow (Y) and the width b of the filter of blue (B), and the lengths of both filters are assumed to be the same. then,

The area ratio of the blue (B) filter = b / (a + b)

Area ratio of filter of yellow (Y) = a / (a + b)

Can be described.

Since the spectral transmittances Tb and Ty of the blue (B) filter and the yellow (Y) filter are known as described above, the filter spectral transmittances Tb and Ty and the filter of the blue (B) The transmittance ratio of the color filter can be obtained from the area ratio (b / (a + b)) and (a / (a + b)).

The transmittance ratio of the color filter is, for example,

(Tb x b / (a + b)) / (Ty x a / (a + b)).

Fig. 15 is a diagram showing an example of characteristics of spectral luminance when the magenta LED and the cyan LED of the illumination device are simultaneously emitted. Fig. The characteristic of the spectral luminance shows that the energy of light of a wavelength near 450 nm and a wavelength of around 580 nm is high. However, the energy of light having a wavelength near 450 nm is stronger than the energy of light having a wavelength around 580 nm. From this characteristic, the luminance ratio of magenta and cyan can be obtained. The luminance ratio of the so-called illumination device can be obtained, for example, by (450 nm luminance / 580 nm luminance).

16 is a graph showing the relationship between the transmittance ratio (Tb x b / (a + b)) / (Ty x a / (a + b)) of the color filter and the luminance ratio (450 nm luminance / On the basis of the chromaticity shift amount? Y from the chromaticity point of white as the reference of the chromaticity.

In Fig. 16, the transmittance ratio of the color filter is shown on the horizontal axis, and the vertical axis is the luminance ratio of the illuminating device.

Here, the luminance ratio of the illuminating device is calculated (luminance of 450 nm / luminance of 580 nm) in the spectral luminance characteristics (shown in Fig. 15) when the magenta and cyan of the illumination device are simultaneously turned on.

? Y = -0.02 or less

? Y = -0.02 to 0.00

Y = 0.00 to 0.02

? Y = 0.02? 0.04

? Y = 0.04 to 0.06

? Y = 0.06 or more

As shown in this graph. The characteristic line of the shift amount? Y = 0.00 from the chromaticity point of white is indicated by a thick dotted line. If the shift amount? Y is 0.00 or less, a white color which is a reference of chromaticity can be obtained satisfactorily.

Therefore, when either the luminance ratio of the illumination device or the transmittance ratio of the color filter is determined in the designing step, the transmittance ratio or the luminance ratio of the other can be determined using the characteristics of the graph.

As described above, the correlation between the filter transmittance ratio determined from the area ratio of the blue filter and the yellow filter and the spectral luminance ratio of the light of magenta and cyan is such that the characteristic including the maintenance of the white point position on the chromaticity diagram to be. Therefore, the above-described correlation can be set to the characteristic of maintaining the white point position on the chromaticity diagram.

The equation representing the characteristic line of the above graph is, for example,

265 - 0.41 × (transmittance ratio of color filter)

-0.041 x luminance ratio of the lighting apparatus =? Y. When the shift amount? Y is 0.00 or less,? Y? 0 can be represented.

According to the above-described embodiment, it is possible to provide a display device and a display method which can suppress power consumption as a whole without significantly lowering the transmission efficiency.

That is, since the apparatus of the embodiment has a color filter, the power efficiency (LED effect) of the lighting apparatus is higher than that of the apparatus of the field sequential system without a filter.

One embodiment of the disclosed invention is as follows.

(1) A liquid crystal display device having a plurality of sub-pixels arranged in a first direction and a second direction crossing the first direction, a color filter corresponding to each sub-pixel, and a lighting device,

Wherein the color filter includes at least an adjacent blue filter and a yellow filter,

The illumination device has a light source, and one frame period of light output from the light source is a display device having at least a period during which cyan light is output and a period during which magenta light is output.

(2) A display device according to (1), further comprising a sub-pixel having a white filter.

(3) The display device according to (1), wherein the light source further includes a period for outputting white light within the one frame period.

(4) The one-frame period of the light output from the light source further includes a period for outputting white light, and the period for outputting the white light is a period during which the cyan light and the magenta light are simultaneously lighted (1).

(5) The display device described in (1), wherein the area of the blue filter is smaller than the area of the yellow filter.

(6) a pixel having the blue filter and the yellow filter and having a substantially square planar shape,

or,

The display device according to (1), wherein the blue filter, the yellow filter, the white filter, and the pixel having a substantially planar shape are included.

(7) The blue filter is arranged in the first direction,

(1) wherein the yellow filter and the white filter are alternately arranged in the first direction.

(8) The blue filter is arranged in the second direction,

(1) wherein the yellow filter and the white filter are arranged alternately in the second direction.

(9) The display device according to (7), wherein one blue filter is assigned to each of one yellow filter and one white filter.

(10) The display device according to (8), wherein one blue filter is assigned to each of one yellow filter and one white filter.

(11) The display device according to (7), wherein one blue filter is shared by one yellow filter and one white filter.

(12) The display device according to (8), wherein one blue filter is shared by one yellow filter and one white filter.

(13) The light source according to (1), wherein the light source is controlled based on a backlight control circuit.

(14) The correlation between the filter transmittance ratio determined from the area ratio of the blue filter and the yellow filter, and the spectral luminance ratio of the magenta to cyan light is a characteristic that maintains the white point position on the chromaticity diagram Display device.

(15) A method of driving a display device having a plurality of sub-pixels arranged in a first direction and a second direction crossing the first direction, a color filter corresponding to each sub-pixel, and a lighting device ,

Wherein the color filter includes at least an adjacent blue filter and a yellow filter,

The lighting device is a driving method of a display device that outputs at least cyan light and magenta light within one frame period.

(16) The lighting device according to (15), wherein the lighting device outputs white light within the one frame period.

(17) The display device according to (15), wherein the illuminating device simultaneously illuminates the cyan light and the magenta light in a field for outputting white light within the one frame period and outputting white light, Driving method.

While specific embodiments of the invention have been described above, these embodiments are presented by way of illustration only and are not intended to limit the scope of the invention. The novel methods and systems described herein may be implemented in a variety of different forms, and further, omission, substitution, and alteration of some of the elements in the form of the methods and systems described herein may be deviated from the spirit of the present invention . Accordingly, the appended claims and their equivalents are intended to cover the above-described embodiments and modifications that fall within the spirit and scope of the invention.

Claims (17)

A plurality of sub-pixels arranged along a first direction and a second direction crossing the first direction,
A color filter corresponding to each sub pixel,
Lighting device
Lt; / RTI &
Wherein the color filter includes at least an adjacent blue filter and a yellow filter,
Wherein the illumination device has a light source and one frame period of light output from the light source has at least a period during which cyan light is output and a period during which magenta light is output. The method according to claim 1,
A display device having a sub-pixel having a white filter. The method according to claim 1,
Wherein the light source further has a period of outputting white light within the one frame period. The method according to claim 1,
Wherein the one frame period of the light output from the light source has a period for outputting white light and the period for outputting the white light is a period in which the cyan light and the magenta light are simultaneously lighted. The method according to claim 1,
And the area of the blue filter is smaller than the area of the yellow filter. The method according to claim 1,
A pixel having the blue filter and the yellow filter and having a substantially square planar shape,
Wherein the display device includes the blue filter, the yellow filter, and the white filter, and has a substantially square planar shape. The method according to claim 1,
The blue filter is arranged in the first direction,
And the yellow filter and the white filter are alternately arranged in the first direction. The method according to claim 1,
The blue filter is arranged in the second direction,
And the yellow filter and the white filter are alternately arranged in the second direction. 8. The method of claim 7,
Wherein one blue filter is assigned to each of one yellow filter and one white filter. 9. The method of claim 8,
Wherein one blue filter is assigned to each of one yellow filter and one white filter. 8. The method of claim 7,
A display device in which one blue filter is shared by one yellow filter and one white filter. 9. The method of claim 8,
A display device in which one blue filter is shared by one yellow filter and one white filter. The method according to claim 1,
Wherein the light source is controlled based on a backlight control circuit. The method according to claim 1,
The correlation between the filter transmittance ratio determined from the area ratio of the blue filter and the yellow filter and the spectral luminance ratio of the magenta and cyan light is determined by the relationship Device. A plurality of sub-pixels arranged in a first direction and a second direction crossing the first direction, a color filter corresponding to each sub-pixel,
A method of driving a display device,
Wherein the color filter includes at least an adjacent blue filter and a yellow filter,
Wherein the illumination device outputs at least cyan light and magenta light within one frame period. 16. The method of claim 15,
Wherein the illumination device outputs white light within the one frame period. 16. The method of claim 15,
The illumination device outputs white light within the one frame period,
And in the field for outputting white light, the cyan light and the magenta light are simultaneously lighted.

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