CN101887183B - Liquid crystal indicator - Google Patents

Abstract

The present invention provides a liquid crystal display device capable of colorless FS driving without using a multicolor light source and capable of color display. The liquid crystal display device has: a liquid crystal display element including first and second segment display parts; a backlight unit including at least a first light source and a second light source, and the first light source is arranged below or on the side of the first segment display part The outside emits light of the first color, and the second light source is arranged below the display part of the second segment to emit light of the second color. The backlight unit makes the light of the first and second colors incident on the first and second segments, respectively. a display unit; and a driving device, which divides one frame into two subframes and performs FS driving, and the driving device controls the liquid crystal display element and the backlight unit in the following manner: for every one frame, the first The segment display is brightly displayed and the first light source is turned on, and the second segment display is brightly displayed and the second light source is turned on in another subframe.

Description

Liquid crystal display device

technical field

The present invention relates to a liquid crystal display device for color display.

Background technique

Liquid crystal display devices capable of segment display or both of segment display and dot matrix display are used in vehicle-mounted information display devices and display units of audio-visual (AV) equipment. As one of the liquid crystal display devices capable of realizing color display in the segment display portion, there is a liquid crystal display device that performs field sequential (FS: fields sequential) driving. In an FS-driven liquid crystal display device, for example, a multi-color backlight including a multi-color light-emitting diode (LED) light source capable of emitting red, green, and blue (RGB) light is used, and the lighting colors are sequentially switched in chronological order, thereby for color display.

A specific example of a conventional FS driving method will be described with reference to FIG. 7 . FIG. 7 is a timing chart showing an input signal of each segment and a lighting state of a backlight. As the liquid crystal display element, a normally black (normally black) type liquid crystal display element is assumed.

In one frame, which is a time unit for displaying one image, three subframes SB1 to SB3 in which the backlights are turned on for R, G, and B are set. For example, the length of one frame is 16.7 ms, and the length of each subframe is 5.57 ms obtained by dividing one frame into three at equal intervals.

In addition, generally speaking, the response of the liquid crystal display element to the applied voltage is slower than that of the backlight to the applied voltage. Therefore, a blank time is required before the liquid crystal display element responds to a certain extent without turning on the backlight.

A blank time B is set immediately after switching of each subframe. The backlight lighting time L for turning on the backlight of the color corresponding to the subframe is from the blanking time B to the end time of each subframe.

If the sub-frame operation is driven at a speed that cannot be recognized by the naked eye (for example, about 16.7 ms/frame, that is, about 5.57 ms/frame), it is possible to realize a color display with flicker suppressed in accordance with the target. In the example shown in FIG. 7 , segment 1 is recognized by the naked eye as a mixed color of R and G, that is, yellow, segment 2 is recognized by the naked eye as a display of magenta, which is a mixed color of R and B, and segment n is recognized by the naked eye as Only G's are displayed in green.

However, in the above-mentioned FS driving method (in order to distinguish this FS driving method from the colorless FS driving method described later, this FS driving method is referred to as a normal FS driving method), especially in areas that are relatively dark around the observer. In some cases, when the viewer's line of sight leaves the display element, or when the element itself is vibrated (such as in the environment inside a car), sometimes the images of each sub-frame are separated, which cannot be recognized by the naked eye under normal conditions. The observed phenomenon is called color break. Considering human psychological factors, this phenomenon cannot be said to be an ideal display state. The color break-up phenomenon is clearly displayed especially in the white display part, so the more light colors of mixed colors, the easier the color break-up phenomenon occurs.

The inventors of the present application have proposed an FS driving method (color-break-free FS driving method) capable of eliminating the color break-up phenomenon (refer to Patent Document 1).

The basic idea of this driving method is to brightly display each segment display section and turn on the backlight of the corresponding display color in only one subframe for each frame. Mix colors without color break-up.

A specific example of the colorless FS driving method will be described with reference to FIG. 8 . FIG. 8 is a timing chart showing an input signal of each segment and a lighting state of a backlight. As the liquid crystal display element, a normally black type liquid crystal display element is assumed.

In this example, one frame is 16.7 ms, and three subframes at equal intervals are set. The backlight emission color is white in the first subframe, orange in the second subframe, and blue in the third subframe. In this driving method, assuming that the number of sub-frames is M, the display colors that can be displayed in one frame are M+1 colors obtained by adding black to the luminous color M. In addition, the interval of each subframe can be changed according to the light emission color of the backlight. That is, subframes may operate at unequal intervals.

In this example, white display is performed in segment 1, orange display is performed in segment n, and segment 2 is in a dark display state (black display). As with the normal FS driving method, a blank time B of about 3 ms is provided to wait for the electro-optical response of the liquid crystal display element after switching subframes for the timing of turning on the backlight. The backlight lighting time L for turning on the backlight of the color corresponding to the subframe is set from the blank time B to the end of the subframe.

By performing such an operation, it is possible to realize a color display without flickering that matches the purpose in appearance without color disturbance.

In the above-mentioned FS drive (normal FS drive and achromatic FS drive), a multi-color light source that changes the lighting color for each subframe is used. A multicolor light source includes light emitting elements that light up, for example, a plurality of primary colors in order to generate a plurality of colors. As a result, for example, the number of light emitting elements used increases and the number of drive IC terminals increases.

[Patent Document 1] Japanese Patent No. 3894323

Contents of the invention

An object of the present invention is to provide a liquid crystal display device capable of field sequential driving without color disturbance and capable of color display without using a multicolor light source.

According to one aspect of the present invention, there is provided a liquid crystal display device comprising: a liquid crystal display element including a first segment display portion and a second segment display portion in a display area; a backlight unit including at least a first segment display portion; A light source and a second light source, the first light source is disposed below the normal direction of the display surface of the first stage display part or laterally outside the first stage display part, and emits light of a first color. 2. The light source is disposed under the second-segment display section but not below the first-segment display section, and emits light of a second color different from the first color, and the backlight unit makes the first light of one color is incident on the first-segment display portion, and light of the second color is incident on the second-segment display portion; Field sequential driving, the driving device controls the liquid crystal display element and the backlight unit in such a way that the first segment display part and the second segment display part use the first color and the The second color is displayed, and the method is as follows: for each frame, the first segment display part is brightly displayed in one subframe, and the first light source is turned on, and the second color is turned on in another subframe. The second-segment display unit performs bright display, and turns on the second light source.

In the display area, a first light source of a first color and a second light source of a second color are used at different positions in the display area, and field sequential driving is performed in which one frame is divided into two sub-frames, and the first segment is used in one sub-frame. The display portion displays with the first color, and in another subframe, the second segment display portion is displayed with the second color, thereby eliminating the need for a multi-color light source, and realizing the possibility of preventing the first color from being mixed with the second color. A liquid crystal display device that operates in color display by mixing colors.

Description of drawings

FIG. 1 is a schematic perspective view of a liquid crystal display device according to first to third embodiments of the present invention.

FIG. 2 is a schematic plan view showing display patterns of the liquid crystal display elements of the first to third examples.

3 is a schematic plan view showing a backlight unit of the liquid crystal display device of the first embodiment.

4A and 4B are timing charts of field sequential driving in the color display mode of the liquid crystal display device of the first embodiment and its modified example, respectively.

5 is a schematic cross-sectional view showing a backlight unit of a liquid crystal display device according to a second embodiment.

6 is a schematic plan view showing a backlight unit of a liquid crystal display device according to a third embodiment.

FIG. 7 is a timing chart showing an example of general field sequential driving.

FIG. 8 is a timing chart showing an example of achromatic random field sequential driving in a comparative example.

Label description

1, 4: polarizing plate; 2: viewing angle compensation plate; 3: liquid crystal unit; 10: liquid crystal display element; 5: backlight unit; 6: driving device; 21-26: segment display unit; 31: diffusion plate; 32W: white Light source; 32Y: yellow light source; 32R: red light source; 33Y: yellow irradiation area; 33R: red irradiation area.

detailed description

First, the common structure of the first to third liquid crystal display devices according to the embodiment of the present invention will be described.

FIG. 1 is a schematic perspective view of a liquid crystal display device of these Examples. A vertical alignment type liquid crystal display element 10 is formed by sandwiching a vertical alignment type liquid crystal cell 3 between polarizers 1 and 4 arranged in crossed Nicols. The vertical alignment type liquid crystal cell 3 includes: upper and lower glass substrates having electrode patterns capable of realizing a desired display formed on inner surfaces; and a liquid crystal layer sandwiched between the upper and lower glass substrates.

The liquid crystal molecules in the liquid crystal layer are aligned in a direction approximately perpendicular to the surfaces of the upper and lower glass substrates when no voltage is applied, but the liquid crystal molecules fall from the vertical direction when a voltage is applied. The vertical alignment type liquid crystal display element 10 is a normally black type display element that performs dark display when no voltage is applied and bright display when voltage is applied.

If necessary, a viewing angle compensation plate may be disposed between the vertical alignment liquid crystal cell 3 and at least one of the upper and lower polarizers 1 and 4 . In this example, a viewing angle compensation plate 2 is disposed between the vertical alignment type liquid crystal cell 3 and the upper polarizing plate 1 . A backlight unit 5 (or 5A, 5B) is disposed below the lower polarizing plate 4 .

The driving device 6 synchronously controls the display state of the liquid crystal display element 10 and the lighting state of the backlight unit 5 (5A, 5B), and performs field sequential driving.

As the response characteristics of the liquid crystal cell 3 of the example, the following assumptions are made. The rising response speed of switching from the dark display state to the bright display state in response to the start of voltage application is about 2 ms, and there is a delay time of about 1.4 ms from the time the voltage is applied until the light transmittance starts to rise. Also, the drop response speed for switching from the bright display state to the dark display state in response to the end of the voltage application is about 2.5 ms.

Next, a display pattern of the liquid crystal display element 10 common to the first to third embodiments will be described.

FIG. 2 is a schematic plan view showing a display pattern of the liquid crystal display element 10 of these Examples. For example, assume an information display panel of an in-vehicle device. On the upper stage of the effective display area 100, a one-segment display unit 21 showing characters such as “AM” and a segment display unit 22 for displaying time are arranged. The character display part 21 of "AM" is arranged on the left side of the time display part 22 . The time display unit 22 has a 3-digit 7-segment display unit and a 1-segment display unit showing “:” (colon) located between the first and second digits from the left.

On the lower stage of the effective display area 100, one-segment display units 23 and 24 displaying characters such as “TEMP” and segment display units 25 and 26 for displaying temperature are arranged on the left and right, respectively. The character display parts 23 and 24 of "TEMP" are respectively arranged above the respective temperature display parts 25 and 26 . Each of the temperature display units 25 and 26 has a 2-digit 7-segment display unit.

These segment display portions are mainly displayed in white, but some of the segment display portions are displayed in color, for example, to draw attention to the user.

In this example, the time display part 22, the left and right "TEMP" character display parts 23 and 24, and the temperature display part 26 on the right are displayed in white. On the other hand, the character display part 21 of "AM" is displayed in yellow, and the temperature display part 25 on the left is displayed in red.

Next, the backlight unit 5 of the liquid crystal display device of the first embodiment will be described. In the liquid crystal display device of the first embodiment, the character display part 21 of "AM" and the temperature display part 25 on the left also display in white normally, but these display parts 21 and 25 display in color under certain circumstances.

FIG. 3 is a schematic plan view showing the backlight unit 5 of the liquid crystal display device of the first embodiment. The backlight unit 5 of the first embodiment includes a diffusion plate 31 having a size corresponding to the effective display area 100 , and light sources 32W, 32Y, 32R of respective colors arranged below the diffusion plate 31 (in the normal direction of the display surface). As the light sources 32W, 32Y, and 32R of the respective colors, for example, inorganic light emitting diodes (LEDs) that can basically be treated as point light sources are used.

The white light sources 32W are arranged at regular intervals throughout the entire effective display region 100 so that the white light transmitted through the diffusion plate 31 illuminates the entire effective display region 100 substantially uniformly. In addition, a white light source is indicated by a crosshatch.

A range larger than the character display portion 21 of “AM” to be displayed in yellow and including the character display portion 21 is the yellow irradiation region 33Y where yellow light is desired to be irradiated. The yellow light source 32Y is selectively arranged below the yellow irradiation region 33Y (under the character display portion 21 of “AM”) so that the yellow light transmitted through the diffusion plate 31 irradiates the yellow irradiation region 33Y substantially uniformly. In addition, the yellow light source is shown with a left slash.

A range larger than the temperature display portion 25 to be displayed in red and including the temperature display portion 25 is the red irradiation region 33R where red light is desired to be irradiated. The red light source 32R is selectively arranged below the red irradiation region 33R (below the temperature display unit 25 ) so that the red light transmitted through the diffusion plate 31 irradiates the red irradiation region 33R substantially uniformly. In addition, the red light source is shown with a right slash.

Through the configuration of the white light source, yellow light source and red light source, the character display part 21 of "AM" can be displayed with white as the main display color and yellow as the secondary display color, and the temperature display part 25 can be displayed with white as the main display color. and red as the secondary display color.

By selectively arranging the light sources of the respective display colors (particularly the sub-display colors) below the corresponding segment display portions, mixing of the display colors is suppressed.

An operation mode in which all the display units display white is called a white display mode. Furthermore, an operation mode in which the character display portion 21 and the temperature display portion 25 display in color in a secondary color other than white, and the remaining display portions display in white as the main color is called a color display mode.

Next, a driving method in the color display mode of the liquid crystal display device of the first embodiment will be described. In the display pattern shown in FIG. 2 , the one-segment display portion of “TEMP” on the right side that displays white is referred to as segment S1, the temperature display portion 25 on the left side that displays red is represented, and the right side Among the 7-segment display parts of digits, the segment display part on the lower right side is called a segment S2, and the one-segment display part of "AM" which displays yellow is called a segment S3.

4A is a timing chart of field sequential driving in the color display mode of the liquid crystal display device of the first embodiment. The voltage application state and light transmittance of each of the segments S1 to S3 , and the lighting state of each color light source are shown.

A drive sequence in which a frame is used as a unit of display time is repeatedly performed. For example, if the frame frequency is 50Hz, 1 frame is 20ms. The figure shows the amount of 2 frames (frames F1 and F2). One frame is divided into two subframes SB1 and SB2. In this example, the frame is equally divided, and one subframe is 10 ms.

First, the voltage application state and light transmittance of each of the segments S1 to S3 will be described. At the beginning of the subframe SB1, voltage application to the segment S1 starts. However, due to the response characteristics of the liquid crystal cell, it takes about 2.0ms to rise the response time from the voltage application to the light transmittance of bright display, and it takes about 1.4ms delay from the voltage application to the light transmittance starts to increase. time. After reaching the light transmittance for bright display until the end of subframe SB1, the bright display state is maintained.

At the end of the subframe SB1 , that is, at the start of the subframe SB2 that follows it, the voltage application to the segment S1 ends. However, due to the response characteristics of the liquid crystal cell, it takes about 2.5 ms to drop the response time from the end of the voltage application to the light transmittance of the dark display.

On the other hand, segments S2 and S3 are voltage-applied in subframe SB2. Segments S2, S3 also exhibit the same change in light transmittance as segment S1 due to the response characteristics of the liquid crystal cell.

Next, the lighting state of each color light source will be described. In the subframe SB2 preceding the subframe SB1, the segment S2 displayed in red and the segment S3 displayed in yellow are in a bright display state. At the end of subframe SB2, that is, at the start of subframe SB1, the voltage application to segments S2 and S3 ends, but a fall response time of approximately 2.5 ms is required before segments S2 and S3 become dark display states .

In order to prevent white light from being mixed into the red display segment S2 and the yellow display segment S3 that were in the bright display state in the previous sub-frame SB2, in the sub-frame SB1, wait for a blank time equivalent to the falling response time (in this example 2.5ms), and then start to light up white. The white lighting will continue until the end of the subframe SB1.

On the other hand, in the subframe SB2, in order to prevent red light and yellow light from being mixed into the white display segment S1 that was in the bright display state in the previous subframe SB1, wait for a blank time from the start time of the subframe, and then start again. Red lights up and yellow lights up. The red lighting and yellow lighting continue until the end moment of the sub-frame SB2.

For each frame, the lighting time of each color is 7.5ms (subframe time 10ms minus blank time 2.5ms).

In this way, in the liquid crystal display device of the first embodiment, the achromatic random field sequential driving is performed for each segment display portion, that is, bright display is performed only in one subframe for each frame.

The achromatic random field sequential driving described with reference to FIG. 8 is taken as a comparative example. The usual colorless random field sequential driving of the comparative example uses a multi-color light source, and by changing the emission color of the multi-color light source for each sub-frame, a desired display color is obtained in each sub-frame.

On the other hand, in the liquid crystal display device of the first embodiment, the monochromatic light sources of the respective display colors (in particular, the sub-display colors) are selectively arranged below the corresponding segment display portions, thereby making it possible to use In the case of multi-color light sources, the field sequential drive without color disturbance is carried out.

By selectively arranging the light sources of the respective display colors (particularly the sub-display colors) below the corresponding segment display portions, color mixing of the display colors is suppressed.

Also, in colorless random field sequential driving, white as the main display color and red and yellow as sub-display colors are displayed in different subframes, thereby preventing color mixture.

However, since red and yellow as secondary display colors are displayed in the same subframe, there is still the possibility of color mixing. In the display pattern of the first embodiment, the temperature display part 25 displayed in red is interposed between the character display part 23 of "TEMP" on the left side which is displayed in white in a subframe different from the subframes displayed in red and yellow. It is separated from the character display part 21 of "AM" displayed in yellow.

In this way, when there are two or more sub-display colors, these display portions are separated from each other via the main white display portion, thereby enhancing the effect of suppressing color mixture between the sub-display colors.

In addition, when the secondary display colors are two or more colors, setting the shortest distance between these display parts (within the display surface) to be 10 mm or more, preferably 20 mm or more, will improve the suppression of color mixing between these display colors. The effect is very ideal.

Also, although the sub-frames for the main white display and the sub-color display have the same time, the sub-frames for the white display may be set to be longer in order to brighten the main white display.

In addition, when all display units are operated in the white display mode for displaying white, the field sequential drive is stopped, the white light source is always turned on on the entire surface, and the liquid crystal display element and the backlight unit are driven asynchronously.

Next, a driving method in the color display mode of a modified example of the first embodiment will be described.

4B is a timing chart of field sequential driving in a color display mode according to a modified example of the first embodiment. The voltage application state and light transmittance of each of the segments S1 to S3 , and the lighting state of each color light source are shown.

As described for the color display mode of the first embodiment, for example, at the end of the subframe SB1, that is, at the start of the subframe SB2, the voltage application to the segment S1 ends, and the segment S1 drops by approximately 2.5 ms. Response speed switches to dim display state.

On the other hand, at the start timing of the subframe SB2, voltage application to the segments S2 and S3 starts, but the segments S2 and S3 remain in the dark display state during a delay time of about 1.4 ms until the light transmittance starts to increase.

Therefore, during a delay time of about 1.4 ms from the start of subframe SB2, segments S2 and S3 remain in the dark display state, while segment S1 remains in a light-transmitting state to some extent.

When the white light source turned on in subframe SB1 is turned on for the delay time at the beginning of subframe SB2, white color mixing can be prevented from occurring in segments S2 and S3, and the display brightness of segment S1 can be increased.

Similarly, if the red light source and the yellow light source turned on in the subframe SB2 are turned on to the initial stage of the subframe SB1, the color mixture of red and yellow in the segment S1 can be prevented, and the display brightness of the segments S2 and S3 can be improved. .

In the color display mode of the modified example of the first embodiment, such extended lighting of the backlight is performed. The lighting extension time in the next subframe is, for example, about 1 ms. Other points are the same as the driving method of the first embodiment.

Next, the liquid crystal display device of the second embodiment will be described. The display pattern of the second embodiment is the same as that of the first embodiment (see FIG. 2 ), but the structure of the backlight unit is different. The second embodiment is also the same as the first embodiment, mainly displaying white, and the character display part 21 of "AM" and the temperature display part 25 on the left are also normally displayed in white, and these display parts 21, 25 for color display.

The backlight unit of the first embodiment has a direct type structure in which light sources of all colors are arranged below the segment display portion. The backlight unit of the second embodiment adopts a side-light structure for the light source of white as the main display color, and a positive light source for the color display colors (red, yellow) as the sub-display color, as explained below. Downside structure.

FIG. 5 is a schematic cross-sectional view showing a backlight unit 5A of a liquid crystal display device according to a second embodiment. A cross section along a dotted line AB crossing the left temperature display portion 25 displayed in red and the right temperature display portion 26 displayed in white in the display pattern shown in FIG. 2 is shown.

The backlight unit 5A of the second embodiment includes a light guide plate 41 having a size corresponding to the effective display area, and a white light source 42W arranged on an end surface of the light guide plate 41 . That is, the white light source 42W is arranged not below the segment display portion for displaying white, but outside on the side, thereby forming an edge-light type backlight structure for white light. The light guide plate 41 irradiates the light emitted from the white light source 42W substantially uniformly above the entire effective display area.

The red light source 42R is selectively arranged below the red irradiation region 43R where red light is desired to be irradiated. The red light reflecting member 44 having a reflective surface that reflects the light from the red light source 42R upward in a manner that defines a range for the in-plane direction guides the light from the red light source 42R to the red irradiation region 43R. .

Similarly, the yellow light source is selectively arranged below the yellow irradiation area where yellow light is desired to be irradiated, and the yellow light reflecting part having a reflective surface guides the light of the yellow light source to the yellow irradiation area, wherein the yellow light reflecting part is defined to The light from the yellow light source is reflected upwards in the manner of a range of in-plane directions. For red light and yellow light, a direct backlight structure is formed.

Also regarding the driving method in the color display mode or the white display mode, the liquid crystal display device of the second embodiment is the same as that of the first embodiment or its modified example.

In the color display mode, the liquid crystal display device of the second embodiment is also for the monochromatic light source in each display color of the color that is the sub-display color, by selectively disposing it below the corresponding segment display portion, Accordingly, field sequential driving without color disturbance can be performed without using a multicolor light source.

Next, the liquid crystal display device of the third embodiment will be described. The display pattern shape of the third embodiment is the same as that of the first embodiment (refer to FIG. 2 ), but the character display part 21 of "AM" and the temperature display part 25 on the left only perform red and yellow color display. That is, the color display unit does not switch to white display, but always performs color display of a predetermined color.

FIG. 6 is a schematic plan view showing a backlight unit 5B of a liquid crystal display device according to a third embodiment. The backlight unit 5B of the third embodiment has a structure in which the white light for irradiating the yellow irradiation region 33Y (53Y) and the red irradiation region 33R (53R) is removed from the backlight unit 5 (see FIG. 3 ) of the first embodiment. Light source 32W (52W).

That is, since the character display part 21 and the temperature display part 25 of "AM" only display yellow and red, respectively, only yellow light sources 53Y and 53R are disposed below these display parts, and white light source 52W is not disposed. The white light source 52W is disposed only below the other display section that performs white display.

The liquid crystal display device of the third embodiment can be said to have removed the operation function in the white display mode from the liquid crystal display device of the first embodiment or its modification, and it is the same as the first embodiment or its modification in the color display mode. Driven accordingly, the same operations as those in the embodiments and modifications are performed.

When the liquid crystal display devices performing the color display operation of the first embodiment and its modifications, the second embodiment, and the third embodiment described above were produced and observed, a good display state was obtained.

As described above, by adopting the backlight structure in which the monochromatic light sources of each color are selectively arranged so that the monochromatic light sources of each color illuminate the corresponding segment display portion, it is possible to perform Color display driven by colorless random field sequence.

In addition, in the above-mentioned embodiment, the liquid crystal display device was exemplified in which two colors (in the embodiment, white) were displayed as color display colors other than the basic display color (white in the embodiment). red and yellow in this example). However, as the color display color to be displayed other than the basic display color, one color or three or more colors may be used as necessary.

In addition, the display pattern of the liquid crystal display device may include a matrix display section in addition to the segment display section for performing color display operations as described in the above-mentioned embodiments.

As products to which the techniques of the above embodiments can be applied, various information display devices can be cited. For example, information display devices for vehicles, display units of audio-visual equipment such as car stereos, and operation panel display units of office equipment such as copiers, etc.

Although the present invention has been described based on the above embodiments, the present invention is not limited thereto. It is obvious to those skilled in the art that various changes, improvements, combinations, and the like are possible, for example.

Claims (5)

1. A liquid crystal display device, the liquid crystal display device has: A liquid crystal display element including a first-segment display portion and a second-segment display portion within a display area; A backlight unit comprising a first light source and a second light source, the first light source emits light of a first color, and the second light source emits light of a second color different from the first color, wherein the first light source illuminating the entire effective display area including the first-segment display unit and the second-segment display unit, the second light source not illuminating the first-segment display unit but illuminating the second the segment display section is illuminated; and a driving device that controls the liquid crystal display element and the backlight unit, divides one frame as a display time unit into two subframes, and performs field-sequential driving; brightly displaying the first segment display portion and turning on the first light source, and brightly displaying the second segment display portion and turning on the second light source in another subframe, so that The first-segment display unit and the second-segment display unit display in the first color and the second color, respectively. 2. The liquid crystal display device according to claim 1, wherein, The liquid crystal display element further includes a third-segment display section separated from the second-segment display section via the first-segment display section, The backlight unit further includes a third light source that is disposed under the third-segment display but not below the first-segment display and the second-segment display and emits light. light of a third color different from the first color and the second color, the backlight unit causing the light of the third color to enter the third-segment display portion, The driving device controls the liquid crystal display element and the backlight unit so that the third-segment display portion is also brightly displayed and the third light source is turned on in the other sub-frame, In addition, in the other sub-frame, the driving device displays the third color on the third-segment display portion while displaying the second color on the second-segment display portion. 3. The liquid crystal display device according to claim 1, wherein, The liquid crystal display element further includes a third-segment display part separated from the second-segment display part by 10 mm or more, The backlight unit further includes a third light source that is disposed under the third-segment display but not below the first-segment display and the second-segment display and emits light. light of a third color different from the first color and the second color, the backlight unit causing the light of the third color to enter the third-segment display portion, The driving device controls the liquid crystal display element and the backlight unit so that the third-segment display portion is also brightly displayed and the third light source is turned on in the other sub-frame, In addition, in the other sub-frame, the driving device displays the third color on the third-segment display portion while displaying the second color on the second-segment display portion. 4. The liquid crystal display device according to any one of claims 1 to 3, wherein: The first color is white. 5. The liquid crystal display device according to any one of claims 1 to 3, wherein: The backlight unit includes a light guide plate extending in a planar shape including the first-segment display portion and the second-segment display portion, the first light source is arranged laterally outside the light guide plate, and The second light source is arranged below the light guide plate below the second segment display part, and the second segment display part can display any one of the first color and the second color.