TWI599824B - Display device, display device driving method - Google Patents

Description

Display device, display device driving method

The present application is based on and claims the prior Japanese Patent Application No. 2014-247904, filed on Dec. 8, 2014, and the priority of Japanese Patent Application No. 2015-222143, filed on Nov. 12, 2015. The entire content of this application is incorporated herein by reference.

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

In recent years, portable terminals have become increasingly popular. The portable terminal includes a smart phone, a PDA device, or a tablet computer, and its display function is also continuously high performance. The portable terminals can display color images.

As a technique for displaying a color image, there is a Field Sequential Color (FSC) method. Previously, the FSC method used red (R) light-emitting devices, green (G) light-emitting devices, and blue (B) light-emitting devices as illumination devices. The FSC method is divided into three periods of the illumination period of the red (R) light-emitting device, the light-emitting period of the green (G) light-emitting device, and the light-emitting period of the blue (B) light-emitting device. For 3 games). Then, in response to each of the three (R, G, B) fields, a pixel for selecting red (selected R pixels), a pixel for displaying blue (selected B pixels), Used to display green and selected pixels (selected G pixels). Alternatively, a point light source can be used as the light emitting device. More specifically, a light emitting diode (LED) can also be used as the point light source.

The selected R pixel, the selected B pixel, and the selected G pixel are from 2 Dimensions are sequentially arranged among a plurality of pixels of the liquid crystal display panel, and pixels corresponding to the R, G, and B signals are selected. The liquid crystal display images of the selected R pixel, the selected B pixel, and the selected G pixel are displayed during independent periods, and the human eye can recognize the color image by the afterimage effect of the eye. Since the liquid crystal display panel does not require a color filter in the FSC method described above, the light utilization rate is high.

a‧‧‧Yellow (Y) filter width

B‧‧‧Blue

b‧‧‧Blue (Y) filter width

BZ‧‧‧Border

CE1‧‧‧ common electrode

CP‧‧‧Drive IC chip

CS‧‧‧ storage capacity

DA‧‧‧ display area

FPC‧‧‧Flexible Printed Circuit Board

FR‧‧‧ framework

G‧‧‧Green

G1‧‧‧ gate wiring

G2‧‧‧ gate wiring

GD‧‧‧1st drive circuit

Gn‧‧‧ gate wiring

G _n-1 ‧‧‧ gate wiring

H1‧‧‧Blue filter width

H2‧‧‧ yellow filter width

LCD‧‧‧liquid crystal display device

LED‧‧‧Light Emitting Diode

LFPC‧‧‧Flexible circuit board

LG‧‧‧Light guide plate

LGA‧‧‧1st main face

LGB‧‧‧2nd main face

LGC‧‧‧ side

LQ‧‧‧ liquid crystal layer

LS‧‧‧ surface light source device

LU‧‧‧Lighting device

OP‧‧‧ openings

OS‧‧‧ optical sheet

OSA‧‧‧ diffusion sheet

OSB‧‧‧ Picture

OSC‧‧‧稜鏡

OSD‧‧‧ diffusion sheet

PE‧‧‧pixel electrode

PNL‧‧‧LCD panel

PX‧‧‧ subpixel

R‧‧‧Red

RS‧‧·reflector

S1‧‧‧ source wiring

S2‧‧‧ source wiring

S3‧‧‧Source wiring

S4‧‧‧ source wiring

SD‧‧‧2nd drive circuit

Sm‧‧‧ source wiring

SUB1‧‧‧1st substrate

SUB2‧‧‧2nd substrate

SW‧‧‧Switching elements

TP‧‧‧double-sided tape

Vcom‧‧‧Feeding Department

W‧‧‧White

X‧‧‧ coordinates

Y‧‧‧ coordinates

Y‧‧‧Yellow

△y‧‧‧Offset

Fig. 1 is an exploded perspective view schematically showing a configuration example of a liquid crystal display device LCD of the present embodiment.

Fig. 2 is a view schematically showing the configuration of a liquid crystal display panel PNL and an equivalent circuit.

Fig. 3A is a view showing an example of the arrangement of the color filters of the sub-pixels and the color of the illumination device.

Fig. 3B is a view showing the relationship between the cyan field and the magenta field in the 1-frame period of the illumination device, and the illuminating color outputted from the color filter.

Fig. 3C is a view showing an example of the intensity of the luminescent color outputted from the color filter with respect to the cyan field and the magenta field of the illumination device.

4A is a view showing another example of the arrangement of the color filters of the sub-pixels and the color of the illumination device.

Fig. 4B is a view showing the relationship between the illuminating colors output from the color filters with respect to the cyan field, the white field, and the magenta field during the frame period of the illumination device.

Fig. 4C is a view showing an example of the intensity of the luminescent color outputted from the color filter with respect to the cyan field, the white field, and the magenta field of the illumination device.

Fig. 5 is a graph showing the transmittances of the blue field and the yellow field, and the luminescence energy of the blue (B) LED, the green (G) phosphor, and the red (R) phosphor.

Figure 6 is a view showing a sub-pixel having a yellow filter of an embodiment and having a blue color The aperture ratio and transmittance of the sub-pixels of the filter are compared with the aperture ratio and transmittance of the sub-pixels without the filter.

7A shows the relationship between the luminances and currents of the LEDs of R, the LEDs of G, and the LEDs of B, and the phosphor LED (for white (W) LEDs when the multiplication result of luminance and current is defined as 100). The result of multiplication of the luminance and current of the component coated with the phosphor, and then the multiplication result is defined as the LED effect.

Fig. 7B is a graph showing the aperture ratio, transmittance, and LED effect of the prior art field sequential method in comparison with the aperture ratio, transmittance, and LED effect of the embodiment of the present application.

Fig. 8A is an explanatory view showing the distance at which the color changes on the chromaticity diagram when the display color changes in the region including the primary colors R, G, and B.

Fig. 8B is an explanatory view showing the distance at which the color changes on the chromaticity diagram when the color of the cyan and magenta regions is changed.

Fig. 9A is a timing chart showing an operation of the illumination device in the case of a white (W) light-emitting field in addition to the cyan illumination field and the magenta emission field.

Fig. 9B shows still another embodiment, that is, the illumination device has a white (W) illumination field in addition to the cyan illumination field and the magenta illumination field, and further, the filter also has yellow, blue, and white colors ( W) Timing diagram of the action of the filter.

Fig. 10A is a view showing an embodiment of a case where the filter includes white (W), yellow (Y), and blue (B).

Fig. 10B is a view showing an example of a pixel circuit corresponding to the filter of Fig. 10A.

Fig. 11A is a view showing another embodiment in the case where the filter includes white (W), yellow (Y), and blue (B).

Fig. 11B is a view showing an example of a pixel circuit corresponding to the filter of Fig. 11A.

Fig. 11C is a view showing another example of the pixel circuit corresponding to the filter of Fig. 11A.

Fig. 12A shows a case where the filter contains white (W), yellow (Y), and blue (B). Further drawings of other embodiments.

Fig. 12B is a view showing an example of a pixel circuit corresponding to the filter of Fig. 12A.

Fig. 12C is a view showing another example of the pixel circuit corresponding to the filter of Fig. 12A.

Fig. 13 is a view showing an example of a graph of the spectral transmittance of the yellow filter and the blue filter.

Fig. 14 is an explanatory view showing an example of calculation of an area ratio of a yellow filter to a blue filter.

Fig. 15 is a view showing an example of characteristics of the luminance of the case where the magenta LED and the cyan LED of the illumination device are simultaneously illuminated.

Fig. 16 is a view showing the blue filter and the spectral transmittance of the two filters shown in Fig. 13 and the area ratio of the two filters shown in Fig. 14 and the spectral brightness shown in Fig. 15; The graph of the transmittance of the yellow filter is compared with the ratio of the luminance of the magenta and cyan illumination devices.

Hereinafter, various embodiments will be described with reference to the additional drawings.

First, the introduction of the embodiment to be described will be described. Since the liquid crystal display panel does not require a color filter in the FSC method, the light utilization rate is high. However, the luminous efficiency of the green (G) LED is about 1/3 of that of the blue (B) LED. If the supply voltage is increased to increase the luminosity of the green (G) LED, there is a problem that power consumption increases. Moreover, due to the red (R) LED, the wavelength associated with chromaticity tends to change over time, so it is necessary to compare the red (R) LED in order to maintain a white region on the chromaticity diagram. The chromaticity of the green (G) LED and the blue (B) LED are adjusted to change the chromaticity. However, this adjustment is technically difficult.

Moreover, there is also a problem that color separation (CBU: color breakup) is caused, which is accompanied by deterioration of image quality. The color separation (CBU) is, for example, a plate having a stripe-shaped hole on a display surface of a liquid crystal display panel in which stripe R, G, and B colors are displayed in a field order, and the plate is placed. When vibrating in the direction in which the stripe intersects, a phenomenon in which a small-width color stripe remains visually remains as an afterimage on the screen viewed from the hole side of the panel. Originally, the display surface is better to look whiter. For example, when the black and white stripes are displayed in the field sequential manner, and the line of sight is quickly moved, the end portions of the black and white stripes appear to be colored.

In order to improve such color separation (CBU), an improvement can be obtained by setting the 1-frame period to add a white (W) field for 3 fields of RGB (also referred to as 3 sub-frames) for a total of 4 fields. However, in order to set 4 fields in the frame, it is necessary to increase the field period of the LED driving circuit from 3 times of the frame period to 4 times. Thereby, the power consumption for driving is increased.

Therefore, an object of the embodiment is to provide a display device and a display device driving method that can suppress power consumption as a whole without significantly reducing the transmittance.

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

It is to be understood that the invention is not limited by the scope of the invention, which is obvious to those skilled in the art. Further, in order to explain more clearly, the width, thickness, shape, and the like of each part are schematically shown in the drawings, but the present invention is not limited to the present invention. In the present specification and the drawings, the same reference numerals are attached to the components that have the same or similar functions as those of the above-described drawings, and the detailed description thereof will be omitted.

Fig. 1 is an exploded perspective view schematically showing a configuration example of a liquid crystal display device LCD of the embodiment. The liquid crystal display device LCD 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, a reflection plate RS, a frame BZ, and the like. The surface light source device LS includes at least a light guide plate LG and a light source unit LU.

The liquid crystal display panel PNL includes a flat first substrate SUB1, a flat second substrate SUB2 disposed opposite the first substrate SUB1, and a liquid crystal layer held between the first substrate SUB1 and the second substrate SUB2. Further, since the liquid crystal layer is extremely thinner than the liquid crystal display panel PNL and is located inside the sealing material to which the first substrate SUB1 and the second substrate SUB2 are attached, the drawings are omitted.

The liquid crystal display panel PNL is a display area DA in which a display image is included in a region where the first substrate SUB1 and the second substrate SUB2 face each other. In the example shown in the figure, there is a case where the display area DA is formed in a rectangular shape and is referred to as an active area. The liquid crystal display panel PNL includes a transmissive liquid crystal display panel having a transmissive display function for displaying an image by selectively transmitting light from the surface light source device LS. The liquid crystal display panel PNL is configured to have a configuration corresponding to a transverse electric field pattern using a transverse electric field substantially parallel to the main surface of the substrate, or a longitudinal electric field using a longitudinal electric field substantially perpendicular to the main surface of the substrate. The composition of the pattern corresponds.

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

The optical sheet OS has light transmittance and is located on the back side of the liquid crystal display panel PNL and at least opposed to the display area DA. The optical sheet OS includes a diffusion sheet OSA, a cymbal OSB, a cymbal OSC, a diffusion sheet OSD, and the like. In the illustrated example, the optical sheets OS are each formed in a rectangular shape. Further, an example of the number of the diffusion sheets or the cymbals included in the optical sheet OS, the laminate, and the like are not limited to the examples shown in FIG. 1 .

The frame FR is located 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 OP that faces the display area DA. The shape of the frame FR is an example and is not limited to the example shown in FIG. Moreover, when the frame FR is not required, it may not be provided.

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

The light guide plate LG is located between the frame FR and the frame BZ. The light guide plate LG is formed in a flat plate shape, and includes a first main surface LGA, a second main surface LGB opposite to the first main surface LGA, and a side surface LGC connecting the first main surface LGA and the second main surface LGB.

The light source unit LU is disposed along the side surface LGC of the light guide plate LG. The light source unit LU includes a plurality of light emitting diode LEDs each functioning as a light source, and a flexible circuit board LFPC or the like for mounting a plurality of light emitting diode LEDs. In the illustrated example, the LEDs are arranged in a row along the side LGC parallel to the short sides of the light guide plate LG. Alternatively, the LEDs may be arranged along the other side (the side crossing the side LGC) parallel to the long sides of the light guide plate LG. That is, in FIG. 1, the light-emitting diode LEDs are arranged in the first direction X, but may be arranged in the second direction Y intersecting therewith. The light-emitting diode LED is driven in a field sequential manner as described in detail later.

The reflector RS is light reflective and is located between the frame BZ and the light guide plate LG. In the illustrated example, the reflector RS is formed in a rectangular shape.

The frame 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, and the reflection plate RS. In the illustrated example, the surface light source device LS is disposed on the back side of the liquid crystal display panel PNL, that is, on the side opposite to the first substrate SUB1, and serves as an illumination device (in this case, a so-called backlight). Play the function.

FIG. 2 is a view schematically showing an example of a configuration of a liquid crystal display panel PNL and an equivalent circuit. The display device includes 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 the first substrate SUB1, and a liquid crystal layer LQ held between the first substrate SUB1 and the second substrate SUB2. Display area The DA system 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 quadrangular shape, for example, and includes a plurality of sub-pixels arranged in a matrix. In this manner, each of the sub-pixels is sequentially arranged in the vicinity of each of the intersections of the gate wiring in the first direction X and the source wiring in the second direction Y, and is provided with a sub-pixel selectively provided for each of the plurality of sub-pixels. Signal drive circuit.

In the present specification, one sub-pixel is referred to as a single pixel circuit and a single color filter. Therefore, in the case of one sub-pixel, one color filter is included and appears as a single color. For a sub-pixel to make a plurality of sets of sub-pixels containing different color filters, the smallest unit that can perform various color representations from the primary color to the intermediate color is simply referred to as a pixel or a composite pixel. As a combination of sub-pixels, there are combinations of sub-pixels including red, green, and blue filters as described later, including a combination of sub-pixels of yellow and blue filters, including yellow, blue, and white filters. A combination of sub-pixels of a light sheet, and the like.

The display area DA of the first substrate SUB1 includes a plurality of gate lines G (G1 to Gn) extending along the first direction X (which may also be referred to as a column direction or a lateral direction) along the first direction X. A plurality of source wirings S (S1 to Sm) extending in the second direction Y (which may also be referred to as a row direction or a vertical direction).

Further, each sub-pixel includes a switching element SW electrically connected to the gate wiring G and the source wiring S, as shown by one on the right side of FIG. 2 (a region surrounded by a chain line). The sub-pixel is electrically connected to the pixel electrode PE of the switching element SW, the common electrode CE1 opposite to the pixel electrode PE, and the like. Although two common electrodes CE1 are shown, they are actually integrated electrodes. The storage capacity CS is formed between, for example, the common electrode CE1 and the pixel electrode PE. The second substrate SUB2 is opposed to the first substrate SUB1 via the liquid crystal layer LQ. In addition, the storage capacity CS may or may not be set as needed. For example, when the liquid crystal display device LCD is in the FFS (Fringe Field Switchig) mode, the pixel electrode PE and the common electrode CE1 and the insulator disposed therebetween or the like function as the storage capacity CS, and thus may not Also set the storage capacity CS.

Each of the gate wirings G (G1 to Gn) is led out to the outside of the display area DA, and is connected to the first drive circuit GD. Each of the source lines S (S1 to Sm) is led out to the outside of the display area DA, and is connected to the second drive circuit SD. For example, at least a part of the first drive circuit GD and the second drive circuit SD are formed on the first substrate SUB1 and connected to the drive IC chip (also referred to as a liquid crystal driver or a drive circuit control unit) CP.

In order to realize the column inversion driving method, the second driving circuit SD can output pixel signals of different polarities when outputting pixel signals with respect to adjacent source lines. The drive IC chip CP has a controller that controls the first drive circuit GD and the second drive circuit SD, and functions as a signal supply source for supplying signals necessary for driving the liquid crystal display panel PNL. In the illustrated example, the driving IC chip CP is mounted on the first substrate SUB1 on the outer side of the display area DA of the liquid crystal display panel PNL.

The common electrode CE1 extends over the entire area of the display area DA and is formed in common with respect to a plurality of sub-pixels. The common electrode CE1 is led out to the outside of the display area DA and connected to the power feeding unit Vcom. The power feeding unit Vcom is formed on, for example, the first substrate SUB1 on the outer side of the display area DA, and is electrically connected to the common electrode CE1. The power feeding unit Vcom is supplied with a fixed common voltage.

Among the plurality of sub-pixels, the color filters are arranged in a specific regular order. The color filter sandwiches the liquid crystal layer LQ and is formed on the second substrate SUB2 opposite to the pixel electrode.

The plurality of sub-pixels described above form, for example, the first row, the second row, the third row, and the ‧ ‧ ‧ the color filter of the first row is blue (B), and the color filter of the second row is yellow (Y), the color is repeated in the first direction X. Further, when the width H1 of the blue color filter is compared with the width H2 of the yellow color filter, the width of the yellow color filter is formed to be wider than the width of the blue color filter.

Fig. 3A shows an example of the arrangement of color filters of each sub-pixel and the color of the illumination device. In order to facilitate understanding of the arrangement of the color filters in FIG. 3A, the configuration of the source wirings S (S1 to Sm) on the first substrate SUB1 side is omitted.

The blue filter (width H1) and the yellow filter (width H2) are arranged in a repeating order in the first direction X (the horizontal direction of the drawing). The color filter is formed on the second substrate SUB2. In the 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 diode LEDs of the illumination device include light-emitting diodes in which the light-emitting colors are cyan and magenta. The plurality of light emitting diode LEDs are mounted on the flexible circuit board LFPC.

The cyan light-emitting diode system can be realized, for example, by laminating a green phosphor with respect to a blue light-emitting diode. The magenta light-emitting diode system can be realized, for example, by laminating a red phosphor with respect to a blue light-emitting diode. The cyan light-emitting diode system is turned on (lighted), for example, during 1/2 of the first half of the frame, and turned off (extinguished) during 1/2 of the second half. On the other hand, the magenta light-emitting diode is turned off (off) during the first half of the first half of the frame, and is turned on (lighted) during the second half of the second half.

The LED array is arranged in a row in parallel with the short sides of the light guide plate. The light emitted from the self-luminous diode LED is incident on the light guide plate. Thereby, the surface light emitted from the light guide plate (the cyan and magenta periodically repeating light) is transmitted through the pixel of the light transmitting state. Here, since the surface illumination z is a field sequential method, the cyan and magenta are periodically repeated light.

Fig. 3B shows the relationship between the illuminating color of the illuminating device, i.e., the cyan, magenta field, and the color of the light emitted from the color filter. The lighting device has a cyan field (1/2 frame) and a magenta field (1/2 frame) during the 1 frame. In the cyan field (1/2 frame), the color displayed on the display surface of the display device is blue (B) and green (G). In contrast, the magenta field (1/2 frame) can be displayed on the display surface of the display device in blue (B) and red (R) colors.

As can be seen from Fig. 3B, blue (B) can be displayed in any of the cyan field and the magenta field. In contrast, green (G) can only be displayed in the cyan field, and red (R) can only be displayed in the magenta field. As a result, there is a tendency that the output level (light emission intensity) of blue (B) is larger than green (G) and red (R).

In order to solve such an imbalance phenomenon, in the present apparatus, for example, as shown in FIG. 3A and FIG. 3C, measures are taken to obtain the luminous intensity of the blue (B), green (G), and red (R) illuminating color balances. Shi.

That is, in order to make the area of the blue filter smaller than the area of the yellow filter, the width H1 of the blue filter is set to be smaller than the width H2 of the yellow filter. Thereby, as shown in FIG. 3C, measures are taken such that the luminous intensity of the blue (B), the luminous intensity of the green (G), and the luminous intensity of the red (R) are substantially equal during the 1-frame period.

Further, in order to obtain white balance, it is not necessary to make the luminous intensity of blue (B), the luminous intensity of green (G), and the luminous intensity of red (R) equal. In order to obtain the position of the white color on the chromaticity diagram, it is preferable to set the luminous intensity of blue (B), green (G), and red (R) after considering the characteristics (transmittance, etc.) of each color filter. .

In the above embodiment, the first 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, it is shown that the 1-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 diode LEDs constituting the illumination device include light-emitting diodes in which the light-emitting colors are cyan, white, and magenta.

Further, the light source unit LU having a plurality of light-emitting diode LEDs shown in FIGS. 3A and 4A is disposed on the end surface 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 an end surface 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 a white light-emitting diode is shown in FIG. 4A, the light source unit LU does not necessarily have a white light-emitting diode. The reason is that the white field system can be provided by simultaneously lighting the cyan and magenta light-emitting diodes as shown in FIG. 9A and FIG. 9B which will be described later.

Fig. 4B is a timing chart showing the division into a cyan field, a white field, and a magenta field during the 1-frame period. Further, the relationship between the illuminating color of the illuminating device, that is, the color of the cyan, white, and magenta fields and the color of the light emitted from the color filter is shown. The lighting device has a cyan field (1/3 frame), a white field (1/3 frame), and a magenta field (1/3 frame) during the 1 frame. In the cyan field (1/3 frame), the colors displayed on the display surface of the display device are blue (B) and green (G). In the white field (1/3 frame), the colors displayed on the display surface of the display device are blue (B), green (G), and red (R). At this time, the result can display white (W). The magenta field (1/3 frame) can be displayed on the display surface of the display device in blue (B) and red (R) colors.

Fig. 4C shows the state in which the illuminating field of white (W = R, G, B) is added except for the cyan field and the magenta field during the frame period shown in Fig. 3C. In this embodiment, since the 1-frame is divided into three fields, the replacement frequency of the illumination device is increased as compared with the case where the first frame of the first embodiment is divided into two fields. However, in the case of a prior device having a W field, there are 4 fields of R, G, B, and W fields, i.e., one less field in this embodiment than the previous device. Therefore, even if the W field is increased, the power consumption amount of the present embodiment does not increase to the extent of the previous device.

Fig. 5 shows the transmittances of the blue filter and the yellow filter corresponding to the wavelength. Further, it indicates a characteristic curve in which the luminous energy of the blue (B) LED, the green (G) phosphor, and the red (R) phosphor changes depending on the wavelength. The characteristic curve indicating the transmittance of the blue filter substantially coincides with the characteristic curve of the luminous energy of the blue (B) LED. The green (G) phosphor's luminescence energy is near the green light of 540 nm to 550 nm through the yellow filter. The red (R) phosphor's luminescence energy is near the red light of 630 nm to 650 nm through the yellow filter.

6 is a view showing comparison between an aperture ratio and a transmittance of a sub-pixel having a yellow filter and a sub-pixel having a blue filter in an embodiment, and an aperture ratio and a transmittance of a sub-pixel having no filter; . The aperture ratio of the sub-pixel without a filter was 78.8%, and the transmittance was 25.3%. On the other hand, in the embodiment, the aperture ratio of the sub-pixel having the yellow filter is 67.0%, the transmittance is 13.0%, and the aperture ratio of the sub-pixel having the blue filter is 57.8%, and the transmittance is 0.34%.

Fig. 7A shows the requirements for reference in order to achieve the LED effect. In FIG. 7A, the luminance (1.7 candela) and current (30 mA) of the red (R) LED, the green (G) LED, and the blue (B) LED are shown. This value indicates that the LED requires a current of 30 mA to obtain 1.7 candle light. The LED effect can be obtained from this value. That is, the LED effect is relative to the luminance level of the current. example For example, find {(1.7)/30}=0.056. Further, the LED effect 0.056 is defined as 100.

On the other hand, Fig. 7A shows the luminance (2.7 candela) and current of a phosphor LED (an element formed by laminating a light-emitting LED of a specific color and applying a phosphor to output a cyan or magenta light). (20mA). This value indicates that a phosphor LED requires a current of 20 mA to obtain 2.7 candelas. According to this value, the LED effect {(2.7)/20}=0.135 can be found. Further, a relative value 251 of 0.056 = 100 according to the previous LED effect was found.

Alternatively, the cyan illumination can be obtained by combining a green (G) luminescent phosphor with an LED emitting blue (B) light. Further, the magenta luminescence can be obtained by combining a red (R) luminescent phosphor with an LED emitting blue (B) light.

The value including the duty cycle loss is further shown in FIG. 7A. The duty ratio is a value derived from a test result in which the LED effect is reduced by about 10% by driving the field sequence.

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 view showing an aperture ratio, a transmittance, and an LED effect of an embodiment of the present application, with respect to an aperture ratio, a transmittance, and an LED effect of the prior field sequential method. The RGB field sequential mode aperture ratio of the LED of R, the LED of G, and the LED of B is 78.8%, the transmittance is 25.3%, and the LED effect is 90.

On the other hand, in the first field sequential mode realized by the blue filter and the yellow filter and the illuminating color of the backlight is cyan or magenta, the aperture ratio is (B=57.8%, Y=67.8). %), the transmittance is 13.3%, and the LED effect is 226 (wherein the ratio of the area ratio of the B filter to the Y filter is 1:2). Or, in the second field sequential mode realized by the blue filter and the yellow filter and the illuminating color of the illuminating device is cyan or magenta, the aperture ratio is (B=49.9%, Y=73.0%). The transmittance is 16.1%, and the LED effect is 226 (wherein the ratio of the area ratio of the B filter to the Y filter is 1:3).

Here, if the transmittance a is multiplied by the LED effect b and the power efficiency of the illumination device is set, the above-described RGB field sequential method is ‧ ‧ ‧ 22.8

The first field of the above mentioned method ‧‧30.1

The second field of the above mentioned method ‧‧36.4

It can be seen that the lighting device of the embodiment of the present application is excellent in electric power efficiency.

Fig. 8A is an arrow symbol indicating the distance at which the color changes on the chromaticity diagram when the display color changes in a region including the primary colors R, G, and B. Further, Fig. 8B is an arrow symbol indicating the distance at which the color changes on the chromaticity diagram when the display color changes in the areas of cyan and magenta. Comparing the two, it can be known that the distance between the display color and the area where the cyan and magenta are changed is shorter than the distance at which the display color changes in the region including the primary colors R, G, and B. This situation means that the chromaticity difference is small when the display color changes. Thereby, the color separation (CBU) phenomenon can be reduced.

Fig. 9A is a timing chart showing the operation of the illumination device in the case of a white (W) light-emitting field in addition to the cyan luminescence field and the magenta luminescence field. In order to obtain a white (W) illuminating field, both the cyan phosphor LED and the magenta phosphor LED are illuminated. Therefore, there is no need for a white (W) light emitting diode as shown in Fig. 4A. Although not shown, the lighting control is performed by an illumination device control circuit (also referred to as a backlight control circuit) in the drive IC chip CP (shown in FIG. 2) for driving the LCD.

Thereby, in the cyan illuminating field, colors of green and blue and green and blue can be displayed, and in the magenta illuminating field, colors of red and blue and red and blue can be displayed. In the white (W) illuminating field, colors of red, green, and blue (ie, white (W)) can be displayed.

Fig. 9B is still another embodiment. In the embodiment of Fig. 9A, the color filter uses a yellow filter and a blue filter. However, in the embodiment of Fig. 9B, the color filter uses a yellow filter, a blue filter, and a white (W) filter. Lighting equipment The order of illumination is the same as in the case of FIG. 9A. That is, the illumination device has a white (W) illumination field in addition to the cyan illumination field and the magenta illumination field.

In the cyan illuminating field, colors such as blue, green, and the like can be displayed. In the magenta illuminating field, colors such as blue, red, and the like can be displayed. Moreover, in the white (W) illuminating field, colors of red, green, and blue (i.e., white (W)) can be displayed.

Fig. 10A is a view showing an embodiment in which the filter includes white (W), yellow (Y), and blue (B). In this embodiment, the areas of the respective filters of white (W), yellow (Y), and blue (B) are formed to be equal. Such white (W), yellow (Y), and blue (B) filters respectively correspond to sub-pixels. The white (W), yellow (Y), and blue (B) filters and the respective sub-pixels can be collectively referred to as one pixel (or unit pixel). Any color of RGB can be displayed by the pixel, and the sub-pixel is used to form a pixel. The shape of the pixel (synthesis filter of white (W), yellow (Y), and blue (B)) is, for example, a square when viewed in a plan view.

Fig. 10B is a view showing an example of a pixel circuit corresponding to the filter of Fig. 10A. Each of the pixel circuits forming each sub-pixel is illustrated in FIG. That is, the pixel circuits of the respective pixels respectively have a switching element including, for example, a thin film transistor (TFT), the gate is connected to the gate line G, the source is connected to the signal line S, and the drain is connected to the driving liquid crystal layer. The pixel electrode of the liquid crystal.

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

Fig. 11B is a view showing an example of a pixel circuit corresponding to the filter of Fig. 11A. Each of the pixel circuits forming each sub-pixel is illustrated in FIG. When viewed in the row direction (the second direction Y), the blue (B) sub-pixels are continuously arranged. However, when the yellow (Y) sub-pixel and the white (W) sub-pixel are observed in the self direction (the second direction Y), they are alternately arranged. Moreover, the yellow (Y) sub-pixel and the white (W) sub-pixel are also observed in the self-column direction (the first direction X). Alternately configured. In this embodiment, the planar shape of the pixel (unit pixel) is also square. Further, in the configuration of FIG. 11B, one blue (B) filter is assigned to each of one yellow (Y) filter and one white (W) filter. That is, in the configuration of FIG. 11B, one blue (B) filter is disposed in one pixel.

Fig. 11C is a view showing another example of the pixel circuit corresponding to the filter of Fig. 11A. The pixel circuit shown in FIG. 11B is different from the pixel circuit shown in FIG. 11C in that blue (B) sub-pixels are formed across two columns. That is, the source and the gate of the switching element of the blue (B) sub-pixel are respectively connected to the gate wiring G1 and the source wiring S1, the switching element and the pixel electrode including the sub-pixel and the blue (B) filter. Expanded from the first column to the second column. Thus, one blue (B) filter is common to one white (W) filter and one white (W) filter. That is, in the configuration of FIG. 11C, one blue (B) filter is disposed across a plurality of pixels.

Fig. 12A is a view showing another embodiment in which the filter includes white (W), yellow (Y), and blue (B). In this embodiment, the yellow (Y) sub-pixel and the white (W) sub-pixel are repeatedly arranged in the column direction (first direction X) of the first column, and blue is arranged in the column direction (first direction X) of the second column. (B) Sub-pixel, one blue (B) sub-pixel has a length of two sub-pixels of white (W) and yellow (Y). In FIG. 12B, which is an example of a pixel circuit corresponding to the filter of FIG. 12A, the source and the gate of the switching element of the blue (B) sub-pixel are respectively connected to the gate wiring G2 and the source wiring S1. The switching element is expanded from the first row to the second row together with the image electrode including the sub-pixel and the blue (B) filter. In this embodiment, the planar shape of the pixel (unit pixel) is also square.

Fig. 12C is a view 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 blue (B) sub-pixel of Fig. 12B is formed across two rows, and the blue (B) sub-pixels shown in Fig. 12C are formed in each row.

Figure 13 is a graph showing the spectral transmittance of a blue (B) filter and a yellow (Y) filter. A diagram of the example. The blue (B) filter easily transmits light of a wavelength near 450 nm (this transmittance is set, for example, to Tb). The yellow (Y) filter easily transmits light of a wavelength near 580 nm (this transmittance is set, for example, to Ty).

Fig. 14 is an explanatory view showing an example of calculation of an area ratio of a blue (B) filter and a yellow (Y) filter with respect to a pixel. For example, the width of the yellow (Y) filter is set to a, the width of the blue (B) filter is set to b, and the lengths of the two filters are the same. It can be recorded that the area ratio of the blue (B) filter = b / (a + b)

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

As described above, since the spectral transmittances Tb and Ty of the blue (B) filter and the yellow (Y) filter are known, the spectral transmittances Tb, Ty, and blue (B) can be used according to the filter. The area ratio (b/(a+b)) and (a/(a+b)) of the filter to the yellow (Y) filter to obtain a transmittance ratio of the color filter.

The transmittance ratio of the color filter can be expressed, for example, as (Tb × b / (a + b)) / (Ty × a / (a + b)).

Fig. 15 is a view showing an example of the characteristics of the spectral brightness when the magenta LED and the cyan LED of the illumination device are simultaneously illuminated. The characteristic of the spectral brightness is that the energy of the light near the wavelength of 450 nm and the wavelength near 580 nm is higher. However, the energy of light near the wavelength of 450 nm is stronger than the energy of light near the wavelength of 580 nm. The luminance ratio of magenta to cyan can be obtained from this characteristic. The luminance ratio of the illumination device can be obtained, for example, (luminance of 450 nm / luminance of 580 nm).

Fig. 16 is a graph showing the transmittance ratio (Tb × b / (a + b)) / (Ty) of the color filter based on the chromaticity shift amount Δy of the white chromaticity point which is the reference of the chromaticity. ×a/(a+b)), a graph showing the relationship between the luminance ratio (450 nm luminance / 580 nm luminance) of the illumination device.

Further, in Fig. 16, the transmittance ratio of the color filter is displayed on the horizontal axis, and the luminance ratio of the illumination device is displayed on the vertical axis.

Here, the luminance ratio of the illumination device simultaneously illuminates the magenta and cyan of the illumination device When the characteristics of the luminance (as shown in Fig. 15) are divided, the result is obtained (luminance of 450 nm luminance / luminance of 580 nm).

△y=-0.02 or less

△y=-0.02~0.00

△y=0.00~0.02

△y=0.02~0.04

△y=0.04~0.06

△y=0.06 or more

The above is shown in the chart. The characteristic line from the white chromaticity point offset Δy=0.00 is indicated by a thick broken line. When the shift amount Δy is 0.00 or less, white which is the basis of chromaticity can be favorably obtained.

Therefore, in the design stage, as long as the luminance ratio of the illumination device or the transmittance ratio of the color filter is determined, the transmittance ratio or the luminance ratio of the other can be determined by the characteristics of the graph.

As described above, the relationship between the transmittance of the filter and the ratio of the luminance of the magenta and cyan light according to the area ratio of the blue filter to the yellow filter maintains the whiteness on the chromaticity diagram. The characteristics of the location of the point. Therefore, the above relationship can be fixed to the characteristic of maintaining the position of the white point on the chromaticity diagram.

The expression indicating the characteristic line of the above chart is, for example, 265-0.419 × (transmission ratio of color filter)

-0.041 × luminance ratio of the illumination device = Δy. When the offset Δy is less than 0.00, it can be expressed as Δy 0.

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 reducing the transmittance.

That is, according to the device of the embodiment, since the color filter is provided, the power efficiency (LED effect) is higher than that of the device illumination device without the field sequential mode of the filter. High, so the overall power efficiency is good.

One aspect of the invention disclosed is as follows.

(1) A display device having a plurality of sub-pixels arranged in a first direction and a second direction intersecting the first direction, a color filter corresponding to each sub-pixel, and an illumination device, and the illumination device The color filter includes at least an adjacent blue filter and a yellow filter; and a display device, wherein the illumination device comprises a light source, and the period of the light output from the light source has at least a period of cyan light output. During the period of output with magenta light.

(2) The display device of (1), which further has a sub-pixel including a white filter.

(3) The display device according to (1), wherein the light source is in a period of the first frame period and further has a period in which white light is output.

(4) The display device according to (1), wherein the period of the first frame period of the light output from the light source further includes a period during which the white light is output, and the period during which the white light is output is simultaneously illuminated by the cyan light and the magenta light. .

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

(6) The display device according to (1), comprising a pixel having the above-described blue filter and yellow filter and having a substantially square shape in plan view, or comprising the above-described blue filter and said yellow filter A sheet and a white filter, and the planar shape is approximately a square pixel.

(7) The display device according to (1), wherein the blue filter is sequentially arranged in the first direction, and the yellow filter and the white filter are alternately arranged in the first direction.

(8) The display device according to (1), wherein the blue filter is sequentially arranged in the second direction, The yellow filter and the white filter are alternately arranged in the second direction.

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

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

(11) The display device according to (7), wherein one yellow filter shares one blue filter with one white filter.

(12) The display device of (8), wherein one yellow filter shares one blue filter with one white filter.

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

(14) The display device according to (1), wherein the relationship between the transmittance of the filter and the luminance of the magenta and cyan light is obtained according to the area ratio of the blue filter and the yellow filter, and the color is maintained. The characteristic of the position of the white point on the graph.

(15) A method of driving a display device, comprising: a plurality of sub-pixels arranged in sequence along a first direction and a second direction crossing the first direction, and each of a color filter corresponding to the sub-pixel, and an illumination device; and the color filter includes at least an adjacent blue filter and a yellow filter; and the illumination device outputs at least cyan light during the frame period With magenta light.

(16) The method of driving a display device according to (15), wherein the illumination device outputs white light during the first frame period.

(17) The driving method of the display device according to (15), wherein the illumination device outputs white light during the first frame period, and simultaneously lights the cyan light and the magenta light in a field of outputting white light.

Although certain embodiments of the invention have been described, such embodiments are by way of example only This is not intended to limit the scope of the invention. In fact, the novel methods and systems described herein may be embodied in a variety of other manners. In addition, various omissions, substitutions and changes can be made in the methods and systems described herein without departing from the spirit of the invention. The scope of the invention and its equivalents are intended to cover the forms and modifications within the scope and spirit of the invention.

H1‧‧‧Blue filter width

H2‧‧‧ yellow filter width

LU‧‧‧Lighting device

LFPC‧‧‧Flexible circuit board

LED‧‧‧Light Emitting Diode

SUB1‧‧‧1st substrate

SUB2‧‧‧2nd substrate

Claims (17)

A display device comprising: a plurality of sub-pixels arranged in sequence along 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 includes at least an adjacent blue filter and a yellow filter; the illumination device has a light source, and the light output from the light source has at least a period of cyan light output and a magenta light output during a frame period of the light output from the light source During the period. The display device of claim 1, further comprising a sub-pixel having a white filter. The display device of claim 1, wherein the light source is in a period of the first frame and further has a period during which white light is output. The display device according to claim 1, wherein the one frame period of the light output from the light source further has a period in which white light is output, and the period in which the white light is output is a period in which the cyan light and the magenta light are simultaneously lit. The display device of claim 1, wherein the area of the blue filter is smaller than the area of the yellow filter. The display device of claim 1, comprising: the blue filter having the blue filter and the yellow filter, and having a substantially square shape; or the blue filter, the yellow filter, and the white A filter, and the planar shape is roughly a square pixel. The display device of claim 1, wherein the blue filter is sequentially arranged in the first direction, The yellow filter and the white filter are alternately arranged in the first direction. The display device according to claim 1, wherein the blue filter is sequentially arranged in the second direction, and the yellow filter and the white filter are alternately arranged in the second direction. A display device according to claim 7, wherein one blue filter is assigned to each of one of the yellow filter and the one of the white filters. The display device of claim 8, wherein one blue filter is assigned to each of the one yellow filter and the one white filter. The display device of claim 7, wherein one of the yellow filters shares one of the blue filters with one of the white filters. The display device of claim 8, wherein one yellow filter shares one blue filter with one white filter. A display device according to claim 1, wherein said light source is controlled based on a backlight control circuit. The display device according to claim 1, wherein the relationship between the ratio of the transmittance of the filter and the ratio of the luminance of the magenta and the cyan light is obtained according to the ratio of the area ratio of the blue filter to the yellow filter. Maintain the characteristics of the white point position on the chromaticity diagram. A driving method of a display device, comprising: a plurality of sub-pixels arranged in a sequence along a first direction and a second direction intersecting the first direction, and corresponding to each sub-pixel a color filter and an illumination device, wherein the color filter includes at least an adjacent blue filter and a yellow filter, and the illumination device outputs at least cyan and magenta light during a frame period . The driving method of the display device of claim 15, wherein the lighting device is as described above White light is output during the frame. The driving method of the display device of claim 15, wherein the illumination device outputs white light during the first frame period and simultaneously illuminates the cyan light and the magenta light in a field for outputting white light.