Patent Grant
10229640
The present invention relates to a liquid crystal display device and a driving method thereof, and more specifically to a technique of suppressing occurrence of color shift in a liquid crystal display device employing a field sequential system.
In general, in a liquid crystal display device that performs color display, one pixel is divided into three sub pixels of a red pixel, a green pixel, and a blue pixel, the red pixel being provided with a color filter that transmits red light, the green pixel being provided with a color filter that transmits green light, the blue pixel being provided with a color filter that transmits blue light. While color display is possible by use of the color filters provided in the three sub pixels, about two-thirds of backlight light applied to a liquid crystal panel is absorbed in the color filters. Hence a liquid crystal display device employing a color filter system has a problem of low efficiency in light utilization. Attention has thus been focused on a liquid crystal display device employing the field sequential system which performs color display without using color filters.
In a typical liquid crystal display device employing the field sequential system, one frame period, which is a display period for one screen, is divided into three fields. Although field is also referred to as sub frame, the term “field” will be used throughout the following description. For example, one frame period is divided into: a field (red field) that displays a red screen based on a red component of an input image signal; a field (green field) that displays a green screen based on a green component of the input image signal; and a field (blue field) that displays a blue screen based on a blue component of the input image signal. By displaying the primary colors one by one as described above, a color image is displayed on the liquid crystal panel. Since the color image is displayed in this manner, the color filters are not required in the liquid crystal display device employing the field sequential system. Accordingly, the efficiency in light utilization of the liquid crystal display device employing the field sequential system is about three times as high as that of the liquid crystal display device employing the color filter system. The liquid crystal display device employing the field sequential system is thus suited for high luminance and lower power consumption.
It should be noted that, in this specification, a color specified by a combination of a data value of a red component, a data value of a green component, and a data value of a blue component (a combination of a data value of a red component, a data value of a green component, a data value of a blue component, and a data value of a white component in a case in which a field that displays a white is provided) while considering display order of colors in a frame is referred to as “order color” for the sake of convenience. For example, a color specified by “first field: R=128, second field: G=32, third field: B=255” is one order color. In this example, colors are displayed in the order of “red, green, blue” in each frame. A data value of a red component is 128, a data value of a green component is 32, and a data value of a blue component is 255. A data value is typically a gradation value.
Meanwhile, in the liquid crystal display device, an image is displayed by controlling a transmittance of each pixel with a voltage (liquid crystal application voltage). In this regard, it takes several milliseconds for the transmittance at a pixel to attain a target transmittance from the start of writing data (applying a voltage) into the pixel, as shown in
Further, in the liquid crystal display device, a sufficient image quality may not be obtained, for example at the time of displaying a moving image, due to a low response speed of the liquid crystal. Then, as one of measures against the low response speed of the liquid crystal, a drive system called overdrive (overshooting drive) has conventionally been adopted. The overdrive is a drive system in which the liquid crystal panel is supplied with a drive voltage higher than a predetermined gradation voltage corresponding to a data value of an input image signal in the current frame or a drive voltage lower than a predetermined gradation voltage corresponding to a data value of an input image signal in the current frame in accordance with a combination of a data value of an input image signal in the preceding frame and a data value of an input image signal in the current frame. That is, the overdrive leads to correction of an input image signal that emphasizes (not a spatial change but) a temporal change in a data value. By adopting such an overdrive, in the liquid crystal display device employing the color filter system, the liquid crystal makes a response such that the transmittance at a pixel attains the target transmittance in each field.
It should be noted that, regarding the present invention, WO 2010/084619 A discloses an invention in which the overdrive is applied to the liquid crystal display device employing the field sequential system.
[Patent Document 1] WO 2010/084619 A
In the liquid crystal display device employing the field sequential system described above, since one frame period is typically divided into three fields, a length of a period for writing data to each pixel is one-third of that in the liquid crystal display device employing the color filter system. Therefore, even in a case in which the overdrive is adopted, depending on the magnitude of the change in a data value of the input image signal from a preceding field, a transmittance at a pixel may not reach a target transmittance within one field as shown in
Moreover, also in terms of “step response of the liquid crystal”, it is difficult for the transmittance at the pixel to reach the target transmittance within one field. Here, “step response of liquid crystal” will be described. When data is written to the pixel, turning on and turning off of the TFT (pixel TFT) is performed in the pixel formation portion, when the TFT is turned off, a charge accumulated in a pixel electrode is held. However, since the response of the liquid crystal is not completed in a very short time, the liquid crystal continues to respond by the electric field even after the TFT changes from an on state to an off state. Here, the relationship “Q=CV” is established between an electric charge Q, a capacitance C, and a voltage V. When the liquid crystal responds after the TFT is turned off, the capacitance C between the electrodes changes, and the voltage V also changes such that the relationship “Q=CV” is satisfied. Therefore, liquid crystal does not respond to the extent that the target transmittance is obtained by writing to the pixel only once. Accordingly, in the liquid crystal display device employing the color filter system, the liquid crystal appears to respond over several frames. The phenomenon that the liquid crystal responds over several frames in such a manner is referred to as “step response of liquid crystal”.
Meanwhile, when a still image is displayed on the liquid crystal display device employing the color filter system, once an image is displayed, the liquid crystal is maintained in a constant state throughout the period until another image is displayed (the liquid crystal does not move). Therefore, an influence of the response characteristics of the liquid crystal on the display quality is relatively small. On the other hand, in the liquid crystal display device employing the field sequential system, a gradation value changes for each field, except when colorless display is performed. Thus, normally, a state of the liquid crystal changes for each field. Further, as described above, in the liquid crystal display device employing the field sequential system, due to the fact that one frame period is divided into a plurality of fields (for example, three fields) and due to the step response of liquid crystal, in each field, the transmittance at the pixel often does not reach the target transmittance until the field makes a transition to a next field. In view of the above, in the liquid crystal display device employing the field sequential system, color shift frequently occurs when color display is performed.
Here, with reference to
As described above, in the liquid crystal display device employing the field sequential system, color shift occurs when an image including an order color (for example, a color specified by “first field: R=255, second field: G=0, third field: B=0” as shown in
Accordingly, an object of the present invention is to realize a liquid crystal display device employing the field sequential system and capable of suppressing occurrence of color shift.
A first aspect of the present invention is directed to a liquid crystal display device employing a field sequential system, the liquid crystal display device having a backlight including light sources of a plurality of colors and configured to perform color display by switching a lighting pattern representing a combination of a lighted state and an unlighted state of the light sources of the plurality of colors in every field, the liquid crystal display device including:
a liquid crystal panel configured to display an image;
a color correction unit configured to perform a color correction processing that changes a saturation of input pixel data representing a color of a pixel without changing a hue thereof and configured to output pixel data obtained by the color correction processing as digital gradation data which are data corresponding to each field;
a digital gradation data correction unit configured to perform correction that enhances a temporal change of data values of digital gradation data outputted from the color correction unit; and
a liquid crystal panel driving unit configured to drive the liquid crystal panel based on digital gradation data after correction by the digital gradation data correction unit; and
the color correction unit performs the color correction processing on the input pixel data such that a color based on pixel data obtained by the color correction processing is a color that can be displayable in the liquid crystal panel by the field sequential system.
According to a second aspect of the present invention, in the first aspect of the present invention,
the color correction unit includes
According to a third aspect of the present invention, in the first aspect of the present invention,
when the color indicated by the input pixel data is a color outside a displayable range in the field sequential system, the color correcting unit performs the color correction processing on the input pixel data such that a color based on pixel data obtained by the color correction processing is a color corresponding to a part, among a region representing the displayable range, that is in contact with a region outside the displayable range, on the color space.
According to a fourth aspect of the present invention, in the third aspect of the present invention,
when, on the color space, a color indicated by the input pixel data is represented by a point C, an intersection of the plane including the point C and having an achromatic axis as a normal and the achromatic axis is represented by a point P, and a point corresponding to a color based on pixel data after correction is represented by D, the color correction unit decides on a distance from the point P to the point D based on coordinates of the point P and an angle between a line segment PC and a straight line obtained by projecting one axis forming the color space on the plane having the achromatic axis as a normal.
According to a fifth aspect of the present invention, in the third aspect of the present invention,
when, on the color space, a color indicated by the input pixel data is represented by a point C, an intersection of the plane including the point C and having an achromatic axis as a normal and the achromatic axis is represented by a point P, and a point corresponding to a color based on pixel data after correction is represented by D, the color correction unit decides on a distance from the point P to the point D based on coordinates of the point P.
According to a sixth aspect of the present invention, in the first aspect of the present invention,
when, on the color space, a color indicated by the input pixel data is represented by a point C, an intersection of the plane including the point C and having an achromatic axis as a normal and the achromatic axis is represented by a point P, a point corresponding to a color based on pixel data after correction is represented by D, a distance from a part, among a region representing a displayable range, that is in contact with a region outside the displayable range to the point P is represented by La, and a maximum value that can be taken as a distance from the point P to a point corresponding to a color indicated by the input pixel data is represented by Lmax, the color correction unit decides on a distance from the point P to the point D such that a ratio of a length of a line segment PC to Lmax is equal to a ratio of a length of a line segment PD to La.
According to a seventh aspect of the present invention, in the first aspect of the present invention,
one frame period is divided into a plurality of fields, the number of the fields is larger than the number of lighting patterns, and
a cycle in which a same lighting pattern appears is shorter than a cycle in which input pixel data for one frame period are inputted.
According to an eighth aspect of the present invention, in the first aspect of the present invention,
one frame period includes a field in which light sources of two or more colors among the light sources of the plurality of colors are turned on.
According to a ninth aspect of the present invention, in the eighth aspect of the present invention,
the light sources of the plurality of colors include red light sources, green light sources, and blue light sources, and
one frame period is divided into four or more fields including a red field in which only the red light sources are turned on, a green field in which only the green light sources are turned on, a blue field in which only the blue light sources are turned on, and a white field in which the red light sources, the green light sources, and the blue light sources are turned on, the four or more fields including at least one field as the red field, at least one field as the green field, at least one field as the blue field, and at least one field as the white field.
According to a tenth aspect of the present invention, in the ninth aspect of the present invention,
when, on the color space, a color indicated by the input pixel data is represented by a point C, and an intersection of the plane including the point C and having an achromatic axis as a normal and the achromatic axis is represented by a point P, the color correction unit sets points on a line segment CP as target processing points one by one from the point C to the point P, determines whether or not each of the target processing points is a point corresponding to a color inside a displayable range, and decides on, based on the determination result, coordinates of a point corresponding to a color based on pixel data after correction.
According to an eleventh aspect of the present invention. In the tenth aspect of the present invention,
the color correction unit allocates data corresponding to each lighting pattern to the four or more fields, the data corresponding to each lighting pattern being obtained by performing a processing that separates a white component from data of each of the target processing points, and
when response is possible in all of the four or more fields, the color correction unit makes a determination that a target processing point is a point corresponding to a color inside the displayable range.
According to a twelfth aspect of the present invention, in the first aspect of the present invention,
when any field among fields included in each frame period is defined as a focused field, a data value of digital gradation data corresponding to the focused field is defined as a display field value, and a data value of digital gradation data corresponding to a preceding field of the focused field is defined as a preceding field value, the digital gradation data correction unit corrects the display field value obtained by the color correction unit depending on the preceding field value obtained by the color correction unit.
According to a thirteenth aspect of the present invention, in the twelfth aspect of the present invention,
the liquid crystal display device further includes a field memory that can hold digital gradation data, for one screen, corresponding to a last field of each frame period among digital gradation data obtained by the color correction unit.
According to a fourteenth aspect of the present invention, in the first aspect of the present invention,
the liquid crystal panel includes
According to a fifteenth aspect of the present invention, in the fourteenth aspect of the present invention,
main components of the oxide semiconductor include an indium, a gallium, a zinc, and an oxygen.
A sixteenth aspect of the present invention is directed to a method of driving a liquid crystal display device employing a field sequential system, the liquid crystal display device having a liquid crystal panel configured to display an image and a backlight including light sources of a plurality of colors and configured to perform color display by switching a lighting pattern representing a combination of a lighted state and an unlighted state of the light sources of the plurality of colors in every field, the method including:
a color correction step of performing a color correction processing that changes a saturation of input pixel data representing a color of a pixel without changing a hue thereof and outputting pixel data obtained by the color correction processing as digital gradation data which are data corresponding to each field;
a digital gradation data correction step of performing correction that enhances a temporal change of data values of digital gradation data outputted by the color correction step; and
a liquid crystal panel driving step of driving the liquid crystal panel based on digital gradation data after correction by the digital gradation data correction step; and
in the color correction step, the color correction processing is performed on the input pixel data such that a color based on pixel data obtained by the color correction processing is a color that can be displayable in the liquid crystal panel by the field sequential system.
According to the first aspect of the present invention, in a liquid crystal display device employing the field sequential system, correction processing that changes the saturation without changing the hue is performed on the input pixel data so that the color after correction is a color that can be displayable by the field sequential system. Since the impression received by a person with respect to the displayed image changes more significantly when the hue changes than when the lightness or the saturation changes, occurrence of color shift is suppressed by performing color correction without changing the hue in this way. From the above, a liquid crystal display device employing the field sequential system and capable of suppressing occurrence of color shift is realized.
According to the second aspect of the present invention, before the color correction processing is performed, processing of allocating data of a plurality of colors to fields is performed in accordance with display order of colors in the frame. Then, in the correction calculation unit, calculation processing is performed based on order data obtained by this allocation. That is, in the correction calculation unit, calculation processing is performed without considering colors in the frame. Since such a configuration is adopted, it is possible to simplify the calculation circuit in the correction calculation unit. Thus, an effect of cost reduction due to reduction in circuit scale can be obtained.
According to the third aspect of the present invention, regarding data of a color that can not be displayed, correction is performed so that the hue does not change and the variation amount for the saturation is as small as possible. Accordingly, occurrence of large color shift is suppressed when a color image is displayed.
According to the fourth aspect of the present invention, similarly to the third aspect of the present invention, occurrence of large color shift is suppressed when a color image is displayed.
According to the fifth aspect of the present invention, the same effect as in the third aspect of the present invention can be obtained with a relatively small memory capacity.
According to the sixth aspect of the present invention, correction is performed on the input pixel data so that data of all colors are data of colors that can be displayed and gradation display can be performed also regarding high saturation colors. Thus, a liquid crystal display device employing the field sequential system, capable of suppressing occurrence of color shift, and capable of performing gradation display also regarding high saturation colors is realized.
According to the seventh aspect of the present invention, one frame period is divided into a plurality of fields, the number of fields is larger than the number of prepared lighting patterns. Then, the cycle in which the same lighting pattern appears is shorter than the cycle in which input pixel data for one frame is inputted. Thus, the frequency of luminance change based on each lighting pattern is increased more than before. As a result, occurrence of flicker is suppressed. From the above, a liquid crystal display device employing the field sequential system and capable of suppressing occurrence of color shift and occurrence of flicker is realized.
According to the eighth aspect of the present invention, one frame period includes a field in which displaying of the mixed color component is performed. Accordingly, occurrence of color breakup is suppressed. From the above, a liquid crystal display device employing the field sequential system and capable of suppressing occurrence of color shift while suppressing occurrence of color breakup is realized.
According to the ninth aspect of the present invention, one frame period includes a field in which displaying of the mixed color components of the three primary colors is performed, in addition to three fields in which monochromatic display of each of the three primary colors is performed. Accordingly, occurrence of color breakup is suppressed more effectively. From the above, a liquid crystal display device employing the field sequential system and capable of suppressing occurrence of color shift while suppressing occurrence of color breakup effectively is realized.
According to the tenth aspect of the present invention, regarding data of a color that can not be displayed, correction is performed so that the hue does not change and the variation amount for the saturation is as small as possible. Accordingly, occurrence of large color shift is suppressed when a color image is displayed. From the above, a liquid crystal display device employing the field sequential system and capable of effectively suppressing occurrence of color breakup and occurrence of color shift is realized.
According to the eleventh aspect of the present invention, the same effect as in the tenth aspect of the present invention can be obtained.
According to the twelfth aspect of the present invention, since the correction amount of the data value when performing overdrive (a difference between a data value before correction and a data value after correction) is determined depending on data value of the preceding field, it is possible to cause the transmittance at each pixel to reach the target transmittance within each field more accurately. Thus, occurrence of color shift is more effectively suppressed.
According to the thirteenth aspect of the present invention, when the correction for overdrive is performed on data of the first field of each frame, it is possible to compare the data value of the first field of the target frame with the data value of the last field of the preceding frame. Thus, when displaying of moving image is performed, correction for overdrive can be effectively performed on data of the first field of each frame. Accordingly, in the liquid crystal display device employing the field sequential system, occurrence of color shift is suppressed even when displaying of moving image is performed.
According to the fourteenth aspect of the present invention, in a liquid crystal display device employing the field sequential system, a thin film transistor in which a channel layer is formed of an oxide semiconductor is used as a thin film transistor provided in a liquid crystal panel. Therefore, in addition to obtaining the effect of high definition and low power consumption, writing speed can be increased as compared with the conventional case. Accordingly, occurrence of color shift is more effectively suppressed.
According to the fifteenth aspect of the present invention, it is possible to surely obtain the same effect as in the fourteenth aspect of the present invention by using indium gallium zinc oxide as the oxide semiconductor forming the channel layer.
According to the sixteenth aspect of the present invention, it is possible to obtain the same effect as in the first aspect of the present invention in a method of driving a liquid crystal display device employing the field sequential system.
Before explaining embodiments, the outline of the present invention will be described with reference to
In the liquid crystal display device employing the color filter system, it is possible to take gradation values from 0 to 255 regarding all of R, G, and B. On the other hand, in the liquid crystal display device employing the field sequential system, since there is “a combination of the preceding gradation value and the current gradation value” in which the transmittance at the pixel can not reach the target transmittance within one field as described above, there are order colors that can not be displayed. Therefore, the order colors that can be displayed in the liquid crystal display device employing the field sequential system are limited to the order colors inside an area indicated by the bold solid line in
From the above, in the liquid crystal display device employing the field sequential system, color shift may occur when a color image is displayed. Therefore, in the present invention, a correction of the data value is performed on the image data so as not to cause color shift as much as possible. It should be noted that, in this specification, data that is the source of the image displayed on the display unit of the liquid crystal display device is collectively referred to as “image data”. That is, the image data includes an input image signal, an input gradation data, a digital gradation data, and the like which will be described later.
By the way, although the order color displayable range varies depending on display order of colors in the frame, the order color displayable range does not vary in the color space in which allocation of colors to each field is performed. In this specification, a color space considering display order of colors in a frame is referred to as “display order color space”. In addition, the three axes forming the display order color space are referred to as “c1 axis”, “c2 axis”, and “c3 axis”, respectively. The c1 axis is the axis associated with a color displayed in the first field, the c2 axis is the axis associated with a color displayed in the second field, and the c3 axis is the axis associated with a color displayed in the third field. For example, when the display order of colors in the frame is “red, green, blue”, the display order color space is formed by the c1 axis associated with red, the c2 axis associated with green, and the c3 axis associated with blue, as shown in
Next, a concept common to all embodiments (including modifications) will be described. Generally, it is known that there are elements “hue”, “lightness”, and “saturation” which are called three psychological attributes in color. Hue is a color shade such as “red . . . yellow . . . green . . . blue . . . purple”. Lightness is the degree of brightness of color. Saturation is the degree of color vividness. These three psychological attributes are generally shown in
Here, with reference to
With reference to
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that, in the following description, a combination of a lighted state and an unlighted state of light sources (LEDs) of a plurality of colors prepared as a backlight is referred to as “lighting pattern”. For example, a pattern such as “red LED: lighted state, green LED: unlighted state, blue LED: unlighted state” (only the red LED is lit) is one lighting pattern.
<1.1 Overall Configuration and Operation Outline>
The liquid crystal display device according to the present embodiment employs the field sequential system.
Regarding
Meanwhile, for example, an oxide TFT (a thin film transistor using oxide semiconductor as a channel layer) may be adopted as the TFT 40 in the display unit 410. More specifically, a TFT whose channel layer is formed of In—Ga—Zn—O (indium gallium zinc oxide) that is oxide semiconductor whose main components include indium (In), gallium (Ga), zinc (Zn), and oxygen (O) (such a TFT is hereinafter referred to as “In—Ga—Zn—O-TFT”) may be adopted as the TFT 40. By adopting such In—Ga—Zn—O-TFT, in addition to obtaining effects of high definition and low power consumption, writing speed can be increased as compared with the conventional case. Alternatively, a transistor using oxide semiconductor other than In—Ga—Zn—O (indium gallium zinc oxide) as the channel layer may be adopted. The same effects are obtained also when a transistor using oxide semiconductor containing, for example, at least one of indium, gallium, zinc, copper (Cu), silicon (Si), tin (Sn), aluminum (Al), calcium (Ca), germanium (Ge), and lead (Pb) as the channel layer is adopted. It should be noted that use of a TFT other than the oxide TFT is not eliminated in the present invention.
Next, the operation of the components shown in
The data correction circuit 120 in the preprocessing unit 100 receives input gradation data (red input gradation data R, green input gradation data G, and blue input gradation data B) outputted from the signal separation circuit 110 and a color order signal SC outputted from the timing controller 200, and performs processing for correcting the data of the order color outside the order color displayable range to the data of the order color inside the order color displayable range so as not to change the hue (color correction processing). Within the data correction circuit 120, first to third digital gradation data, which are digital gradation data for the first to third fields, are generated by this color correction processing. The data correction circuit 120 further performs correction for overdrive on the first to third digital gradation data. Then, the data correction circuit 120 outputs the data obtained as described above as applied gradation data (applied gradation data d(1) to d(3) for the first to third fields). It should be noted that the data correction circuit 120 will be described in more detail later.
In the first to third field memories 130(1) to 130(3), the applied gradation data d(1) to d(3) for the first to third fields outputted from the data correction circuit 120 are stored respectively.
The timing controller 200 reads the applied gradation data d(1) to d(3) for the first to third fields from the first to third field memories 130(1) to 130(3) respectively, and outputs a digital video signal DV; a gate start pulse signal GSP and a gate clock signal GCK which are for controlling the operation of the gate driver 310; a source start pulse signal SSP, a source clock signal SCK, and a latch strobe signal LS which are for controlling the operation of the source driver 320; and an LCD driver control signal S1 which is for controlling the operation of the LED driver 330.
The gate driver 310 repeats application of the active scanning signal to each gate bus line GL with one vertical scanning period as a cycle based on the gate start pulse signal GSP and the gate clock signal GCK which are sent from the timing controller 200.
The source driver 320 receives the digital video signal DV, the source start pulse signal SSP, the source clock signal SCK, and the latch strobe signal LS which are sent from the timing controller 200, and applies the driving video signal to each source bus line SL. At this time, in the source driver 320, the digital video signal DV indicating the voltage to be applied to each source bus line SL is sequentially held at the timing when the pulse of the source clock signal SCK is generated. Then, at the timing when the pulse of the latch strobe signal LS is generated, the held digital video signals DV are converted into analog voltages. The converted analog voltages are simultaneously applied to all source bus lines SL1 to SLn as driving video signals.
The LED driver 330 outputs a light source control signal S2 for controlling the state of each LED constituting the backlight 490 based on the LED driver control signal S1 sent from the timing controller 200. In the backlight 490, switching of the state of each LED (switching between the lighted state and the unlighted state) is performed as appropriate based on the light source control signal S2.
An image corresponding to the input image signal DIN is displayed on the display unit 410 of the liquid crystal panel 400 by applying the scanning signals to the gate bus lines GL1 to GLm, applying the driving video signals to the source bus lines SL1 to SLn, and switching the state of each LED as appropriate, as described above.
<1.2 Data Correction Circuit>
Next, the configuration and operation of the data correction circuit 120 will be described in detail.
<1.2.1 Color Correction Unit>
To the data allocating unit 1222 in the color correction unit 122, the color order signal SC outputted from the timing controller 200 and the input gradation data (red input gradation data R, green input gradation data G, and blue input gradation data B) are inputted. The color order signal SC is a signal indicating the display order of colors in the frame. In the present embodiment, the color order signal SC indicates that the display order of the colors in the frame is “red, green, blue”. The data allocating unit 1222 allocates the input gradation data (red input gradation data R, green input gradation data G, and blue input gradation data B) to three fields according to the color order signal SC. In the present embodiment, the red input gradation data R is allocated to the first field, the green input gradation data G is allocated to the second field, and the blue input gradation data R is allocated to the third field. That is, from the data allocating unit 1222, the data value of the red input gradation data R is outputted as the first field value C1, the data value of the green input gradation data G is outputted as the second field value C2, and the data value of the blue input gradation data B is outputted as the third field value C3.
The correction calculation unit 1224 in the color correction unit 122 includes a calculation circuit. The correction calculation unit 1224 performs color correction processing (calculation processing using the calculation circuit) on the first to third field values C1 to C3 outputted from the data allocating unit 1222, and outputs data after correction as first to third digital gradation data D1 to D3. By the way, in the data allocating unit 1222, allocation of the input gradation data to the fields is performed according to the display order of colors in the frame. Then, the correction calculation unit 1224 performs calculation processing based on the data of order that is data obtained by allocating the input gradation data (data of a plurality of colors) to the fields without considering colors in the frame.
Here, the color correction processing in the present embodiment will be described in detail. As described above, in the liquid crystal display device according to the present invention, by changing the saturation while maintaining the hue, the processing of correcting the image data outside the order color displayable range to the image data inside the order color displayable range is performed. As a method of performing such a processing, a method is considered in which a conversion table associating data before correction (data corresponding to the first to third field values C1 to C3) with data after correction (data corresponding to first to third digital gradation data D1 to D3) is prepared for each display order and data is corrected using the conversion table (see
After starting the color correction processing, first, a plane including the point C and having the pseudo achromatic axis 52 as a normal is assumed, and the coordinates of the point P representing the achromatic color on the plane are obtained (step S110). Since the point P is a point representing the achromatic color, the values of the c1 axis, the c2 axis, and the c3 axis are all equal. That is, the coordinates of the point P are represented by (m, m, m) (m is an integer from 0 to 255 in the present embodiment). Further, the point P is a point which has the shortest distance from the point C, among the points on the pseudo achromatic axis 52. From the above, the value of m is calculated by the following equation (1).
Next, the distance L between the point C and the point P is calculated (step S120). When assuming that the distance between the original point O and the point P is represented by M, and the distance between the original point O and the point C is represented by N, the following equation (2) is established from the Pythagorean theorem.
[Expression 2]
L=√{square root over (N2−M2)} (2)
Also, since the coordinates of the original point O are (0, 0, 0), the distance M between the original point O and the point P is represented by the following equation (3), and the distance N between the original point O and the point C is represented by the following equation (4).
[Expression 3]
M=√{square root over (m2+m2+m2)} (3)
[Expression 4]
N=√{square root over (C12C22+C32)} (4)
Based on the above equations (1) to (4), the distance L between the point C and the point P is represented by the following equation (5).
Next, cos θ is calculated where θ is an angle between the straight line obtained by projecting the c1 axis on the plane having the pseudo achromatic axis 52 as a normal (the line indicated by reference character 53 in
The vector b is represented by (1, 0, 0). Further, since the following equation (7) is established, cos θ is represented by the following equation (8).
In step S130, cos θ is calculated as described above.
In the present embodiment, the maximum distances (the maximum distances from the achromatic point) La (see
Thereafter, it is determined whether or not the value of L is larger than the value of La (step S150). As a result, when the value of L is less than or equal to the value of La, data correction (correction of order color) is not performed. That is, the first to third field values C1 to C3 are outputted as they are as the first to third digital gradation data D1 to D3 from the correction calculation unit 1224. On the other hand, when the value of L is larger than the value of La, the color corresponding to the point D located at the distance La from the point P toward the point C in the display order color space is set as the order color after correction (step S160). That is, the coordinates (D1, D2, D3) of the point D are calculated, and the calculated data values are outputted from the correction calculation unit 1224 as the first to third digital gradation data D1 to D3. It should be noted that the coordinates (D1, D2, D3) of the point D are represented by the following equation (9) by using vectors.
The coordinates (D1, D2, D3) of the point D are calculated by substituting values on the right side of the above equation (9).
As described above, correcting image data outside the order color displayable range to image data inside the order color displayable range is performed so as not to change the hue.
<1.2.2 Digital Gradation Data Correction Unit>
Next, the digital gradation data correction unit will be described in detail. The first field digital gradation data correction unit 124(1) receives the third digital gradation data D3 and the first digital gradation data D1, and performs correction for overdrive on the first digital gradation data D1 depending on the data value (gradation value) of the third digital gradation data D3. The second field digital gradation data correction unit 124(2) receives the first digital gradation data D1 and the second digital gradation data D2, and performs correction for overdrive on the second digital gradation data D2 depending on the data value (gradation value) of the first digital gradation data D1. The third field digital gradation data correction unit 124(3) receives the second digital gradation data D2 and the third digital gradation data D3, and performs correction for overdrive on the third digital gradation data D3 depending on the data value (gradation value) of the second digital gradation data D2. Hereinafter, how to perform correction for overdrive will be described in detail focusing on any one order color.
Incidentally, in the gradation value conversion look-up table 125 shown in
It should be noted that, if an increase in memory capacity is permitted, then the configuration may be such that ail of the gradation values that can be expressed by the liquid crystal panel 400 are stored in the gradation value conversion look-up table 125 as preceding field values and display field values. According to this configuration, although the capacity of the memory to be mounted on the liquid crystal display device increases, occurrence of color shift is more effectively suppressed since error due to the interpolation calculation does not occur.
<1.3 Effects>
According to the present embodiment, in the liquid crystal display device employing the field sequential system, data of a color that can not be displayed is corrected to data of a displayable color by lowering the saturation without changing the hue. At that time, the color in which the variation amount for the saturation is the smallest among the displayable colors is taken as the color after correction. In this manner, since the correction is performed so that the hue does not change and the variation amount for the saturation is as small as possible, occurrence of a large color shift is suppressed when the color image is displayed. It should be noted that, by adopting an oxide TFT as the TFT 40 in the display unit 410, in addition to obtaining effects of high definition and low power consumption, writing speed can be increased as compared with the conventional case. As a result, occurrence of color shift is more effectively suppressed. Further, in the present embodiment, since the overdrive is performed, the displayable range is wider than when the overdrive is not performed. Accordingly, it is possible to make the color after correction closer to the color before correction.
From the above, schematically, for example, in a case in which displaying of a color indicated by reference character 80 in
Further, according to the present embodiment, before performing the color correction processing, allocating data of three colors (red input gradation data R, green input gradation data G, and blue input gradation data B) to three fields (first to third fields) is performed. Then, in the correction calculation unit 1224 (see
<1.4 Modifications>
<1.4.1 First Modification>
In the first embodiment, correction for overdrive is performed based on gradation values of two fields included in the same frame in the digital gradation data correction unit 124. Therefore, as for the gradation value of the red field which is the first field of the frame, correction for overdrive is performed depending on the gradation value of the blue field which is the third field of the current frame. When the still image display is performed, there is no problem even with such a configuration. However, when the moving image display is performed, since the gradation value of each field varies frame by frame, the desired effect due to the overdrive can not be obtained in a case in which the above configuration is adopted. This is because, in order to perform correction for the overdrive on the gradation value of the first field of a certain frame (the Nth frame in
According to the present modification, when correction for the overdrive is performed on the data of the first field of each frame, it is possible to compare the gradation value of the first field of the target frame and the gradation value of the last field of the preceding frame. Thus, when moving image display is performed, correction for overdrive can be effectively performed also on the data of the first field of each frame. As a result, occurrence of color shift is suppressed even when moving image display is performed in the liquid crystal display device employing the field sequential system.
<1.4.2 Second Modification>
In the liquid crystal display device employing the field sequential system, one frame period is typically divided into three fields, as described above. Then, images of different colors are displayed in the three fields. The images of the three fields are superimposed on the observer's retina by the image lag phenomenon, whereby the image for one frame is perceived by the observer. In such a liquid crystal display device employing the field sequential system, lighting state of the light source (backlight) varies every field. In the case of the first embodiment, only the red LEDs are turned on in the first field, only the green LEDs are turned on in the second field, and only the blue LEDs are turned on in the third field. Since the lighting state of the light source varies every field in this manner, the drive frequency of the entire light source is 180 Hz when the frame frequency is 60 Hz in the liquid crystal display device in which one frame period is divided into three fields. However, when paying attention to the light source of only one color, the drive frequency of the light source of the target color is 60 Hz. Generally, it is known that a change in the lighting state is perceived by the observer as flicker when the lighting state of the light source is controlled with a driving frequency of less than 70 Hz. Although the luminance of the light source is constant in the liquid crystal display device employing the color filter system, the luminance change depending on the driving frequency of the light source of each color (monochromatic light source) occurs in the liquid crystal display device employing the field sequential system. Since luminance change occurs at a frequency of 60 Hz for each color in this manner, flicker is perceived by human eyes. Therefore, in the liquid crystal display device according to the present modification, the occurrence of flicker is suppressed by increasing the frequency of luminance change by the configuration described below.
In the present modification, the applied gradation data d(1)′ generated based on the red input gradation data R is outputted from the first displaying color digital gradation data correction unit 128(1), the applied gradation data d(2)′ generated based on the green input gradation data G is outputted from the second displaying color digital gradation data correction unit 128(2), and the applied gradation data d(3)′ generated based on the blue input gradation data B is outputted from the third displaying color digital gradation data correction unit 128(3).
The field allocating unit 129 allocates the applied gradation data d(1)′ to d(3)′ to the four fields depending on the frame count signal Fcnt. It should be noted that “0”, “1”, and “2” are sequentially repeated for the data value of the frame count signal Fcnt. The data value of the frame count signal Fcnt changes at the timing when the frame is switched. Specifically, the data value of the frame count signal Fcnt is 0 in the frame in which lighting patterns appear in the order of “the third lighting pattern, the second lighting pattern, the first lighting pattern, the third lighting pattern”, the data value of the frame count signal Fcnt is 1 in the frame in which lighting patterns appear in the order of “the second lighting pattern, the first lighting pattern, the third lighting pattern, the second lighting pattern”, and the data value of the frame count signal Fcnt is 2 in the frame in which lighting patterns appear in the order of “the first lighting pattern, the third lighting pattern, the second lighting pattern, the first lighting pattern”.
With reference to
When the data value of the frame count signal Fcnt is 0, the field allocating unit 129 allocates the applied gradation data d(1)′ to d(3)′ to the four fields (first to fourth fields F1 to F4) as follows.
First field F1: the applied gradation data d(3)′, namely data based on the blue input gradation data B
Second field F2: the applied gradation data d(2)′, namely data based on the green input gradation data G
Third field F3: the applied gradation data d(1)′, namely data based on the red input gradation data R
Fourth field F4: the applied gradation data d(3)′, namely data based on the blue input gradation data B
When the data value of the frame count signal Fcnt is 1, the field allocating unit 129 allocates the applied gradation data d(1)′ to d(3)′ to the four fields (first to fourth fields F1 to F4) as follows.
First field F1: the applied gradation data d(2)′, namely data based on the green input gradation data G
Second field F2: the applied gradation data d(1)′, namely data based on the red input gradation data R
Third field F3: the applied gradation data d(3)′, namely data based on the blue input gradation data B
Fourth field F4: the applied gradation data d(2)′, namely data based on the green input gradation data G
When the data value of the frame count signal Fcnt is 2, the field allocating unit 129 allocates the applied gradation data d(1)′ to d(3)′ to the four fields (first to fourth fields F1 to F4) as follows.
First field F1: the applied gradation data d(1)′, namely data based on the red input gradation data R
Second field F2: the applied gradation data d(3)′, namely data based on the blue input gradation data B
Third field F3: the applied gradation data d(2)′, namely data based on the green input gradation data G
Fourth field F4: the applied gradation data d(1)′, namely data based on the red input gradation data R
In the present modification, the allocation of data as described above is repeated with three frames as a cycle. Here, since the frame frequency in the present modification is 60 Hz and one frame period is divided into four fields, the drive frequency of the entire light source is 240 Hz. Further, although one frame period is divided into four fields, screens of the same color are displayed every three fields since allocation of data is performed as described above. Thus, the frequency of the luminance change is 80 Hz.
From the above, according to the present modification, the display is performed at the refresh rate (update frequency) of 80 Hz, apparently. As a result, occurrence of flicker is suppressed. Accordingly, a liquid crystal display device employing the field sequential system and capable of suppressing occurrence of color shift and occurrence of flicker is realized.
<2.1 Configuration and the like>
The overall configuration, the configuration of the data correction circuit, and the configuration of one frame period are the same as those in the first embodiment, and therefore the description thereof is omitted (see
<2.2 Color Correction Processing>
Meanwhile, in the first embodiment, in the displayable range table, the maximum distances La are held so as to correspond to the combination of m and cos θ (see
Thereafter, it is determined whether or not the value of L is larger than the value of Lm (step S240). As a result, when the value of L is less than or equal to the value of Lm, data correction (correction of order color) is not performed. That is, the first to third field values C1 to C3 are outputted as they are as the first to third digital gradation data D1 to D3 from the correction calculation unit 1224. On the other hand, when the value of L is larger than the value of Lm, the color corresponding to the point D located at the distance Lm from the point P toward the point C in the display order color space is set as the order color after correction (step S250) (see
As described above, correcting image data outside the order color displayable range to image data inside the order color displayable range is performed so as not to change the hue.
<2.3 Effects>
According to the present embodiment, a liquid crystal display device employing the field sequential system and capable of suppressing the occurrence of color shift can be realized with a smaller memory capacity than the first embodiment.
<3.1 Configuration and the like>
The overall configuration, the configuration of the data correction circuit, and the configuration of one frame period are the same as those in the first embodiment, and therefore the description thereof is omitted (see
<3.2 Color Correction Processing>
In the first embodiment, when the value of L is larger than the value of La, the color corresponding to the point D located at the distance La from the point P toward the point C in the display order color space is set as the order color after correction (see
When assuming that the point representing any focused order color is represented by C, first, the values of m, L, and cos θ are obtained in the same manner as in the first embodiment. A displayable range table similar to that of the first embodiment is provided in the present embodiment, and the value of La is obtained based on the value of m and the value of cos θ. A point corresponding to the order color where the distance from the pseudo achromatic axis 52 is Lmax in the display order color space is one of a point on the plane formed by the c1 axis and the c2 axis, a point on the plane formed by the c2 axis and the c3 axis, and a point on the plane formed by the c3 axis and the c1 axis. Here, when assuming that a point corresponding to the order color after correction is D and a distance between the point P and the point D is Lo, the coordinates of the point D are determined such that “Lmax:L=La:Lo” is established. From the above, in the present embodiment, the correction is performed also on the data of the order color inside the order color displayable range such that the gradation display is performed also regarding the color having the high saturation.
Next, the distance Lo (see
Then, the color corresponding to the point D located at the distance Lo from the point P toward the point C in the display order color space is set as the order color after correction (step S360). That is, the coordinates (D1, D2, D3) of the point D are calculated, and the calculated values are outputted as the first to third digital gradation data D1 to D3 from the correction calculation unit 1224. It should be noted that the coordinates (D1, D2, D3) of the point D are represented by the following equation (12) by using vectors.
As described above, the correction on the image data is performed such that all of the order colors after correction become order colors inside the order color displayable range without changing the hue and that gradation display is performed regarding the color having the high saturation.
<3.3 Effects>
According to the present embodiment, regarding any order color, the coordinates of the point D corresponding to the order color after correction are determined such that “Lmax:L=La:Lo” is established, in the above-described display order color space (see
<3.4 Modification>
In the third embodiment, as in the first embodiment, the distance from the achromatic point P to the point corresponding to the order color after correction is obtained based on the value of m and the value of cos θ. However, instead of this, the distance from the achromatic point P to the point corresponding to the order color after correction may be obtained depending on only the value of m without depending on the value of cos θ, as in the second embodiment.
<4.1 Outline and Overall Configuration>
As for the liquid crystal display device employing the field sequential system, there is conventionally known a problem of occurrence of color breakup.
<4.2 Data Correction Circuit>
<4.2.1 Color Correction Unit>
To the correction calculation unit 1224 in the color correction unit 122, the color order signal SC outputted from the timing controller 200 and the input gradation data (red input gradation data R, green input gradation data G, and blue input gradation data B) outputted from the signal separation circuit 110 are inputted. The color order signal SC is a signal indicating the display order of colors in the frame. In the present embodiment, the color order signal SC indicates that the display order of the colors in the frame is “red, green, blue, white”. The correction calculation unit 1224 performs the color correction processing described below on the input gradation data and outputs data after correction as the first to third digital gradation data D1 to D3.
In the present embodiment, in order to display a white screen in the fourth field, a processing for separating white data from RGB data (hereinafter referred to as “white color separation processing”) is performed at the time of color correction processing. The data conversion by this white color separation processing will be described. For example, it is assumed that components of each color before conversion are as shown by reference character 86 in
From the above, when assuming that the magnitude of the red component, the magnitude of the green component, and the magnitude of the blue component before the white color separation processing are represented by R1, G1, and B1, respectively, and the magnitude of the white component, the magnitude of the red component, the magnitude of the green component, and the magnitude of the blue component after the white color separation processing are represented by W2, R2, G2, and B2, respectively, W2, R2, G2, and B2 are obtained by the following equations (13), (14), (15), and (16), respectively.
W2=Z (13)
R2=R1−Z (14)
G2=G1−Z (15)
B2=B1−Z (16)
Here, when assuming that the function representing the minimum value among x, y, and z is defined as min (x, y, z), Z=min (R1, G1, B1) holds true in the above equation (13).
It should be noted that the calculus equation for the component of each color is not limited to the above equations (13) to (16). For example, the magnitude W2 of the white component, the magnitude R2 of the red component, the magnitude G2 of the green component, and the magnitude B2 of the blue component after white color separation processing may be obtained by the following equations (17), (18), (19), and (20), respectively, using a separation coefficient k which is an integer from 0 to 1.
W2=kZ (17)
R2=R1−kZ (18)
G2=G1−kZ (19)
B2=B1−kZ (20)
Next, the color correction processing in the present embodiment will be described in detail. The order color displayable range can be estimated by the response characteristics of the liquid crystal in each liquid crystal display device. Regarding the liquid crystal display device that sequentially displays four colors as in the present embodiment, the order color displayable range is estimated as a range of the four dimensional space. Thus, it is possible to prepare a conversion table that associates data before correction and data after correction for each display order, and correct data using the conversion table. However, in order to store the data of the four dimensional space in the conversion table, a huge memory capacity is required. Therefore, in the present embodiment, occurrence of color breakup and occurrence of color shift are suppressed without providing a huge memory capacity by performing the color correction processing as described below.
Next, the coordinates (RGB values) of C(0) to C(255) when assuming that 256 points dividing a line segment connecting the point C and the point P into 255 equal parts are represented by C(0) to C(255) are obtained (step S420). It should be noted that the point C(0) is the point C and the point C(255) is the point P.
Thereafter, it is determined whether or not the order color corresponding to each point is a color inside the displayable range until the point corresponding to the order colors inside the displayable range is specified, in the order of “point C(0), point C(1), point C(2), . . . , point C(255)” (step S430 to step S480). Thus, the displayable range for the color having the same hue as the color corresponding to the point C is estimated, and the data value of the color after correction is determined based on the estimation result.
As described above, the processings of step S430 to step S480 are performed one point by one point in the order of “point C(0), point C(1), point C(2), . . . , point C(255)” until the point corresponding to the order colors inside the displayable range is specified. Here, the point being processed out of the points C(0) to C(255) is referred to as “target processing point”. Hereinafter, the processings of step S430 to step S480 will be described.
First, the above-described white color separation processing is performed on the data of the target processing point (step S430). By this white color separation processing, four data values Wa, Ba, Ga, and Ba are calculated. Then, allocating four data values (Wa, Ra, Ga, and Ba) to the four fields (first to fourth fields) is performed (step S440).
Next, regarding each field, it is determined whether or not response is possible, based on the data value (display field value) of the display field (field to be judged) and the data value (preceding field value) of the field preceding the display field (step S450 to step S480). It should be noted that the term “response is possible” here means that the liquid crystal responds so that a target transmittance can be obtained within a predetermined time when a voltage corresponding to the data value allocated to each field is applied to the liquid crystal.
Incidentally, in the present embodiment, a response capability table 1228 as shown in
Specifically, first, it is determined whether or not response is possible with respect to the first field, based on the data value of the first field and the data value of the fourth field of the preceding frame (step S450). As a result of the determination, when it is determined that response is possible, the processing proceeds to step S460, and when it is determined that response is impossible, the processing returns to step S430. When the processing returns to step S430, the next point becomes the target processing point.
In step S460, it is determined whether or not response is possible with respect to the second field, based on the data value of the second field and the data value of the first field. As a result of the determination, when it is determined that response is possible, the processing proceeds to step S470, and when it is determined that response is impossible, the processing returns to step S430.
In step S470, it is determined whether or not response is possible with respect to the third field, based on the data value of the third field and the data value of the second field. As a result of the determination, when it is determined that response is possible, the processing proceeds to step S480, and when it is determined that response is impossible, the processing returns to step S430.
In step S480, it is determined whether or not response is possible with respect to the fourth field, based on the data value of the fourth field and the data value of the third field. As a result of the determination, when it is determined that response is impossible, the processing returns to step S430. On the other hand, when it is determined that response is possible, the data value of the target processing point at the time, that is obtained after performing allocation to each field in step S440, is set as the corrected data value of the point C. The data values obtained as described above are outputted as the first to fourth digital gradation data D1 to D4 from the correction calculation unit 1224.
For example, in a case in which it is determined that response is possible in the above step S480 when the target processing point is point C(10), the data value obtained based on the data value of the point C(10) is set as the corrected data value of the color corresponding to the point C. More specifically, in this case, data values obtained by allocating the four data values (Wa, Ra, Ga, and Ba) that are obtained by performing the white color separation processing on the data value (RGB value) of the point C(10) to four fields (first to fourth fields) are set as the corrected data values of the color corresponding to the point C.
<4.2.2 Digital Gradation Data Correction Unit>
Next, the digital gradation data correction unit will be described. The first field digital gradation data correction unit 124(1) receives the first digital gradation data D1 and the fourth digital gradation data D4 stored in the delaying field memory 126 (namely, the fourth digital gradation data D4 of the preceding frame), and performs correction for overdrive on the first digital gradation data D1 depending on the data value (gradation value) of the fourth digital gradation data D4. The second field digital gradation data correction unit 124(2) receives the first digital gradation data D1 and the second digital gradation data D2, and performs correction for overdrive on the second digital gradation data D2 depending on the data value (gradation value) of the first digital gradation data D1. The third field digital gradation data correction unit 124(3) receives the second digital gradation data D2 and the third digital gradation data D3, and performs correction for overdrive on the third digital gradation data D3 depending on the data value (gradation value) of the second digital gradation data D2. The fourth field digital gradation data correction unit 124(4) receives the third digital gradation data D3 and the fourth digital gradation data D4, and performs correction for overdrive on the fourth digital gradation data D4 depending on the data value (gradation value) of the third digital gradation data D3. It should be noted that the method of correcting the gradation value in each digital gradation data correction unit 124 is the same as that in the first embodiment.
<4.3 Effects>
According to the present embodiment, in the liquid crystal display device employing the field sequential system, data of a color that can not be displayed is corrected to data of a displayable color by lowering the saturation without changing the hue, similarly to the first embodiment. Further, in the present embodiment, one frame period includes the first field displaying the red screen, the second field displaying the green screen, the third field displaying the blue screen, and the fourth field displaying the white screen. That is, one frame period includes a field in which displaying of the mixed color components of the three primary colors is performed, in addition to three fields in which monochromatic display of each of the three primary colors is performed. Accordingly, occurrence of color breakup is suppressed. From the above, a liquid crystal display device employing the field sequential system and capable of suppressing occurrence of color shift while suppressing occurrence of color breakup is realized.
<4.4 Modification>
In the fourth embodiment, one frame period is divided into four fields, and each of the first to fourth lighting patterns appears once in each frame. However, the present invention is not limited to this. The configuration in which the number of fields included in one frame period is larger than the number of lighting patterns (configuration in the present modification) may be adopted.
First frame FR1
Second frame FR2
Third frame FR3
Fourth frame FR4
Since display order of colors (order in which lighting patterns appear) differs depending on the frame as described above, the value of the color order signal SC given from the timing controller 200 to the correction calculation unit 1224 changes for each frame.
According to the present modification, as in the fourth embodiment, in the liquid crystal display device employing the field sequential system, it is possible to suppress the occurrence of color shift while suppressing occurrence of color breakup. Further, similar to the second modification of the first embodiment, the occurrence of flicker is suppressed since the apparent refresh rate (frequency of change in luminance) is increased.
The present invention is not limited to each of the above-described embodiments (including modifications), and various modifications can be made without departing from the scope of the present invention.
100: preprocessing unit
110: signal separation circuit
120: data correction circuit
122: color correction unit
124(1) to 124(5): first to fifth field digital gradation data correction unit
125: gradation value conversion look-up table
126: delaying field memory
128(1) to 128(3): first to third displaying color digital gradation data correction unit
130(1) to 130(5): first to fifth field memory
200: timing controller
310: gate driver
320: source driver
330: LED driver
400: liquid crystal panel
410: display unit
490: backlight
1222: data allocating unit
1224: correction calculation unit
1226: white color separation unit
1228: response capability table
| Number | Date | Country | Kind |
|---|---|---|---|
| 2015-039869 | Mar 2015 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2016/055360 | 2/24/2016 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2016/140119 | 9/9/2016 | WO | A |
| Number | Name | Date | Kind |
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| 20050041047 | Miyata | Feb 2005 | A1 |
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| 20130010017 | Kobayashi et al. | Jan 2013 | A1 |
| 20160071449 | Miyata et al. | Mar 2016 | A1 |
| 20160104444 | Miyata | Apr 2016 | A1 |
| Number | Date | Country |
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| 2010084619 | Jul 2010 | WO |
| 2011132455 | Oct 2011 | WO |
| 2014185109 | Nov 2014 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 20180053474 A1 | Feb 2018 | US |
