KR20150035248A - Liquid crystal display apparatus and method of driving the same - Google Patents

Liquid crystal display apparatus and method of driving the same Download PDF

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Publication number
KR20150035248A
KR20150035248A KR20130115577A KR20130115577A KR20150035248A KR 20150035248 A KR20150035248 A KR 20150035248A KR 20130115577 A KR20130115577 A KR 20130115577A KR 20130115577 A KR20130115577 A KR 20130115577A KR 20150035248 A KR20150035248 A KR 20150035248A
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South Korea
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light
liquid crystal
light source
color
pixel
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KR20130115577A
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Korean (ko)
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임현덕
박재병
윤선태
조현민
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삼성디스플레이 주식회사
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Priority to KR20130115577A priority Critical patent/KR20150035248A/en
Publication of KR20150035248A publication Critical patent/KR20150035248A/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133509—Filters, e.g. light shielding masks
    • G02F1/133514—Colour filters
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133528—Polarisers
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133615—Edge-illuminating devices, i.e. illuminating from the side
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133524—Light-guides, e.g. fibre-optic bundles, louvered or jalousie light-guides

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  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • Mathematical Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Liquid Crystal (AREA)
  • Liquid Crystal Display Device Control (AREA)

Abstract

Disclosed are a liquid crystal display apparatus and a method of driving the same. In the liquid crystal display apparatus, a backlight unit, a first polarizing plate, a polarization changing panel, a first liquid crystal panel, and a second polarizing plate are successively arranged. The backlight unit includes a first light source which emits a color beam, and a second light source which emits a different color beam from at least part of the first light source. The first light source and the second light source are operated by time division. The first liquid crystal panel includes a color filter which displays a color image by using a beam emitted from the backlight unit. The polarization changing panel changes the polarization of selectively passing beams.

Description

[0001] The present invention relates to a liquid crystal display apparatus and a driving method thereof,

A liquid crystal display device and a driving method thereof.

The liquid crystal display device is one of the most widely used flat panel display devices, and includes a lower substrate having pixel electrodes, an upper substrate having a common electrode, and a liquid crystal layer interposed between the two substrates.

When a voltage is applied between the pixel electrode and the common electrode, an electric field is formed in the liquid crystal layer. The formed electric field changes the arrangement of the liquid crystal molecules constituting the liquid crystal layer, and thus the polarization of the light passing through the liquid crystal layer changes. The amount of light transmitted through the polarizing plate is changed in accordance with the change in polarization of light passing through the liquid crystal layer. Therefore, since the amount of light passing through the polarizing plate can be changed by adjusting the electric field size formed on the liquid crystal layer, the image can be displayed using the same.

There is a liquid crystal display device in which a plurality of light sources are applied to a liquid crystal display device, and the plurality of light sources are illuminated in a time-division manner and liquid crystal is driven pixel by pixel to display an image. In the liquid crystal display device of this type, color mixing between colors may occur due to slow motion of the liquid crystal during time division driving.

Provided is a liquid crystal display device and a driving method thereof that are capable of preventing color mixing between colors due to slow motion of liquid crystal during time division driving.

A liquid crystal display device according to an embodiment of the present invention includes a first light source that emits one color light and a second light source that emits light including at least a portion of a color different from the first light source, A backlight unit adapted to drive one light source and the second light source in a time division manner; A first liquid crystal panel including a color filter arranged to display a color image using light emitted from the backlight unit; A polarization changing panel adapted to change polarized light of selectively passing light; A first polarizer disposed between the backlight unit and the polarization changing panel; And a second polarizer disposed on the liquid crystal panel.

The first liquid crystal panel may have an electrode structure capable of driving the color filter, the liquid crystal layer, and the pixel unit or the sub pixel unit.

The polarization changing panel may include a second liquid crystal panel having a structure corresponding to the first liquid crystal panel and without a color filter.

The polarization changing panel may be provided so as to be driven in units of pixels or sub-pixels corresponding to the first liquid crystal panel.

The polarization changing panel may be provided so as to change polarization of light passing through in the ON operation state and pass the light passing through in the OFF operation state without polarization change.

The polarization changing panel operates in an on state during the operation time of another light source turned on in a time division manner during image display using light emitted from one light source among the first light source and the second light source in pixel units or sub- The polarization of the light passing through the pixel or sub-pixel can be changed.

The polarization changing panel may operate in an off state for a remaining time to allow light passing through the pixel or sub-pixel to pass through without change in polarization.

The first light source includes a plurality of first light sources, and the second light source includes a plurality of second light sources, wherein the first light source and the second light source may be arranged in an array or in a mixed manner with each other.

The first light source includes a plurality of first light sources, the second light source includes a plurality of second light sources, the first light source includes a blue light emitting element, the second light source includes a yellow light emitting element, One light source and the second light source may be arranged in an array or mixed with each other.

The color filter of the first liquid crystal panel may include a first sub pixel region through which the first color light passes, a second sub pixel region through which the second color light passes, and a transparent third sub pixel region, .

Wherein the first color light and the second color light are obtained from the light emitted from the second light source.

One of the first color light and the second color light may be a red light and the other may be a green light.

According to the method for driving a liquid crystal display device according to the embodiment of the present invention, during the image display using the light emitted from one light source among the first light source and the second light source, during the operation time of another light source turned on in a time- Operating in an ON state on a pixel-by-pixel or sub-pixel basis; And changing the polarization of light passing through the corresponding pixel of the polarization changing panel so that light emitted from the other light source is blocked by the second polarizing plate.

According to the liquid crystal display apparatus and the driving method thereof as described above, when a color image is implemented by sequentially driving a plurality of light sources in a time division manner by arranging the polarization changing panel between the liquid crystal panel and the lower polarizer plate, The problem of color mixing between colors that may occur due to the slowness of the liquid crystal can be improved.

1 schematically shows a liquid crystal display according to an embodiment of the present invention.
2 shows an example of a light source arrangement of a backlight unit that can be applied to the liquid crystal display of FIG.
FIGS. 3A and 3B schematically illustrate an embodiment of a liquid crystal panel that can be applied to a liquid crystal display according to an embodiment of the present invention, and a driving principle thereof.
4 shows an example of a polarization changing panel.
Fig. 5 shows the progress of the light during the OFF operation of the polarization changing panel.
Fig. 6 shows the progress of light during the ON operation of the polarization changing panel.
FIG. 7 shows a driving principle for preventing color mixing of a liquid crystal display according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. The effects and features of the present invention and methods of achieving them will be apparent with reference to the embodiments described in detail below with reference to the drawings. However, the present invention is not limited to the embodiments described below, but may be implemented in various forms.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein like reference numerals refer to like or corresponding components throughout the drawings, and a duplicate description thereof will be omitted .

 In the following embodiments, the terms first, second, and the like are used for the purpose of distinguishing one element from another element, not the limitative meaning.

In the following examples, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise.

In the following embodiments, terms such as inclusive or possessive are intended to mean that a feature, or element, described in the specification is present, and does not preclude the possibility that one or more other features or elements may be added.

In the following embodiments, when a part of a film, an area, a component or the like is on or on another part, not only the case where the part is directly on the other part but also another film, area, And the like.

In the drawings, components may be exaggerated or reduced in size for convenience of explanation. For example, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, and thus the present invention is not necessarily limited to those shown in the drawings.

 If certain embodiments are otherwise feasible, the particular process sequence may be performed differently from the sequence described. For example, two processes that are described in succession may be performed substantially concurrently, and may be performed in the reverse order of the order described.

1 schematically shows a liquid crystal display 10 according to an embodiment of the present invention. 2 shows an example of the light source arrangement of the backlight unit 20 which can be applied to the liquid crystal display 10 of Fig.

1 and 2, a liquid crystal display 10 according to an embodiment of the present invention includes a backlight unit 20, a liquid crystal panel 50, a polarization changing panel 40, a first polarizing plate A lower polarizing plate 30, and a second polarizing plate, for example, an upper polarizing plate 60. The lower polarizer 30 may be positioned between the backlight unit 20 and the polarization changing panel 40 and the upper polarizing plate 60 may be positioned on the liquid crystal panel 50.

2, the backlight unit 20 includes first light sources 21a and 23a that emit one color light and second light sources 21a and 23b that emit light including colors different from the first light sources 21a and 23a at least in part The first light sources 21a and 23a and the second light sources 21b and 23b may be provided to drive the first light sources 21a and 23b and the second light sources 21b and 23b in a time division manner. The first light sources 21a and 23a include a plurality of first light sources and the second light sources 21b and 23b include a plurality of second light sources. The first light sources 21a and 23a and the second light sources 21b, and 23b may each be an array or may have a mixed arrangement. FIG. 2 shows an example in which the first light sources 21a and 23a and the second light sources 21b and 23b are mixed with each other. The backlight unit 20 may include a light guide plate 25 that guides light incident from the first light sources 21a and 23a and the second light sources 21b and 23b and outputs the light in a plane direction.

For example, the backlight unit 20 includes a light guide plate 25 and light source arrays 21 and 23 on both sides of the light guide plate 25. The light source array 21 includes first light sources 21a and 21b, The light source array 23 may have an arrangement in which the first light source 23a and the second light source 23b are alternately arranged to be mixed with each other.

The plurality of first light sources 21a and 23a of the light source arrays 21 and 23 may include a plurality of first light emitting devices, for example, a plurality of blue light emitting devices. The plurality of second light sources 21b and 23b of the light source arrays 21 and 23 may include a plurality of second light emitting devices such as a plurality of yellow light emitting devices. Herein, the case where the first light sources 21a and 23a are provided with the blue light emitting element and the second light sources 21b and 23b are provided with the yellow light emitting element will be exemplarily described. However, the first light sources 21a and 23a, The liquid crystal display devices 21b and 23b may be composed of various color light source combinations or a combination of a one-color light source and a white light source within a range in which the liquid crystal display device 10 according to the embodiment of the present invention can implement a color image.

The one light source array 21 may be arranged such that the plurality of first light sources 21a constitute an array and the other light source array 23 may constitute an array of the plurality of second light sources 21b. Also, the light source array in which the first and second light sources 21a and 21b are alternately arranged may be located only on one side or the other side of the light guide plate 25.

1, the backlight unit 20 includes a diffusion sheet 29 and a prism sheet 27 that are positioned on the light guide plate 25 and allow the light to diffuse toward the liquid crystal panel 50, And a reflective sheet 26 provided under the light guide plate 25. Here, the backlight unit 20 shown in FIG. 1 is shown as an example, and the configuration of the backlight unit 20 can be variously modified. 1 and 2 show a case in which the backlight unit 20 is provided in an edge structure in which the first and second light sources 21a and 23a and 21b and 23b are disposed on the light guide plate 25, It may have a direct-under-structure positioned below.

The first light sources 21a and 23a and the second light sources 21b and 23b are driven by time division. That is, the first light sources 21a and 23a and the second light sources 21b and 23b may be alternately turned on for a predetermined time interval at a predetermined time interval. 6, which will be described later, the first light sources 21a and 23a are driven and turned on for a predetermined time, the backlight unit 20 is maintained in the off state, and then the second light sources 21b And 23b, respectively. In this manner, the backlight unit 20 can drive the first light sources 21a and 23a and the second light sources 21b and 23b to output light alternately for a predetermined period of time, at predetermined time intervals.

The liquid crystal panel 50 is provided to display a color image using light emitted from the backlight unit 50 and may include a color filter and a liquid crystal layer. The liquid crystal panel 50 may have an electrode structure for driving the liquid crystal array of the liquid crystal layer on a pixel-by-pixel or sub-pixel basis.

For example, as the liquid crystal panel 50, a liquid crystal panel 130 having a structure as shown in FIGS. 3A and 3B can be applied.

3A and 3B schematically illustrate an embodiment of a liquid crystal panel 50 that can be applied to the liquid crystal display 10 according to the embodiment of the present invention and its driving principle. 3A and 3B show only a backlight unit and a liquid crystal panel 130 in a simplified excerpt. The backlight unit includes a first light source 110, a second light source 115, and a light guide plate 120. FIG.

Referring to FIGS. 3A and 3B, the liquid crystal panel 130 may include a color filter and a liquid crystal layer 135. The liquid crystal panel 130 may include an electrode structure for driving the liquid crystal array of the liquid crystal layer 135 on a pixel-by-pixel or sub-pixel basis.

For example, the liquid crystal panel 130 includes first and second substrates 131 and 139, a driving unit 133 including a thin film transistor (TFT) on the first substrate 131, A liquid crystal layer 135 positioned between the first and second substrates 131 and 139, a common electrode 136 provided inside the second substrate 139, and a second substrate 131, which are electrically connected to the thin film transistor, And a color filter provided in the color filter 139.

The pixel electrode may be composed of three sub-pixel electrodes 134A, 134B and 134C, and TFTs may be arranged correspondingly. That is, three TFTs and three sub-pixel electrodes 134A, 134B, and 134C may be included in one pixel. The color filter includes a first sub pixel region 137A for passing first color light A in correspondence with three sub pixel electrodes 134A, 134B and 134C in a region corresponding to one pixel, A second sub pixel region 137B through which the color light B passes, and a transparent third sub pixel region 137C.

The yellow light emitted from the second light source 110 is guided to the liquid crystal panel 130 via the light guide plate 25 and the yellow light emitted from the second light source 110, The first color light A transmitted through the first sub pixel area 137A of the color filter is incident on the second color pixel area 137B of the color filter through the red color light R, The light B may be green light G and the light C transmitted through the third sub pixel region 137C may be yellow light. As described above, the first color light A transmitted through the first sub pixel region 137A of the color filter and the second color light B transmitted through the second sub pixel region 137B of the color filter are transmitted through the second light source Can be obtained from the light emitted from the light source 110. At this time, one of the first color light A and the second color light B may be red light, for example, and the other may be green light, for example.

When the backlight unit includes a blue light emitting element that emits blue light, for example, as the first light source 115, the blue light emitted from the first light source 115 passes through the first sub pixel region 137A of the color filter, The second sub pixel region 137B can not transmit, and only the transparent third sub pixel region 137C is transparent. In this case, the light D passing through the third sub pixel region 137C becomes blue light.

Therefore, when the first and second light sources 115 and 110 are provided in the backlight unit and the first light source 115 and the second light source 110 are alternately driven by time division, It becomes possible to realize a red (R), green (G), and blue (B) color image.

Here, the blue light emitting device and the white light emitting device may be provided as the first light source 115 and the second light source 110 in the backlight unit. In this case, when the second light source 110 is driven, The first color light A transmitting through the pixel region 137A may be red light R and the second color light B transmitting through the second sub pixel region 137B may be green light G, The light C transmitted through the sub pixel region 137C may be white light. When the first light source 115 is driven, the blue light emitted from the first light source 115 can not pass through the first sub pixel region 137A and the second sub pixel region 137B of the color filter, Only the sub pixel region 137C is transmitted. In this case, the light D passing through the third sub pixel region 137C becomes blue light. Therefore, even when the backlight unit includes the blue light emitting element and the white light emitting element as the first and second light sources 115 and 110 and the first light source 115 and the second light source 110 are alternately driven by time division, , Red (R), green (G), and blue (B) color images.

In addition, the color combination of the first light source 115 and the second light source 110 applied to the backlight unit can be variously modified within a range in which a color image can be realized.

In the above description, the pixel electrode is composed of three sub-pixel electrodes 134A, 134B and 134C, and three sub-pixel regions 137A, 137B and 137C (corresponding to 137C ), But the embodiment of the present invention is not limited thereto. For example, a region corresponding to one pixel of the pixel electrode and the color filter is provided so as to have four sub-pixel arrays such as red (R), green (G), blue (B), and white And the driving method of the liquid crystal display device 10 may be changed accordingly.

Referring again to Fig. 1, the polarization changing panel 40 may be provided to change the polarization of the selectively passing light. The polarization changing panel 40 may be provided so as to be capable of driving in units of pixels or sub-pixels corresponding to the liquid crystal panel 50. In the ON operation state, the polarization changing panel 40 changes the polarization of light passing therethrough, It can be provided to pass light without changing polarized light.

The polarization changing panel 40 is turned on in time division during video display using light emitted from one light source among the first light sources 21a and 23a and the second light sources 21b and 23b in pixel units or sub pixel units May operate in an on state during the operation time of another light source to change the polarization of light passing through the pixel or sub-pixel. In addition, the polarization changing panel 40 can operate in the off state for the remaining time, and can pass the light passing through the pixel or the sub-pixel without changing polarization.

For example, the polarization changing panel 40 may include a liquid crystal panel having a structure corresponding to the liquid crystal panel 50 and having no color filter. For example, the polarization changing panel 40 may have a structure in which the color filter is excluded from the liquid crystal panel 130 of FIGS. 3A and 3B.

Fig. 4 shows an example of the polarization changing panel 40. Fig. Components substantially the same as those in Figs. 3A and 3B are denoted by the same reference numerals and repetitive descriptions are omitted.

4, the polarization changing panel 40 includes first and second substrates 131 and 139, a driving unit 133 including a thin film transistor (TFT) on the first substrate 131, a driving unit 133 A liquid crystal layer 135 positioned between the first and second substrates 131 and 139 and a common electrode 136 provided inside the second substrate 139. The pixel electrode electrically connected to the thin film transistor Configuration.

The pixel electrode may be composed of three sub-pixel electrodes 134A, 134B, and 134C, and corresponding TFTs of the driver 133 may be arranged. That is, it may be included in three TFTs and three sub-pixel electrodes 134A, 134B and 134C in one pixel.

The polarization changing panel 40 can change the polarized light by changing the liquid crystal arrangement of the liquid crystal layer in units of sub-pixels.

The liquid crystal display 10 according to the embodiment of the present invention as described above may be applied to the backlight unit 20, the lower polarizer 30, the polarization changing panel 40, the liquid crystal panel 50 and the upper polarizer 60 .

According to the liquid crystal display 10 according to the embodiment of the present invention, even when a predetermined pixel of the liquid crystal panel 50 is driven so that light passes through the upper polarizer 60, as shown in Figs. 5 and 6, The light may not pass through the upper polarizer plate 60 or pass through the upper polarizer plate 60 depending on whether the corresponding pixel of the polarization changing panel 40 is in the OFF operation state or the ON operation state.

Fig. 5 shows the progress of light in the OFF operation of the polarization changing panel 40. Fig. Fig. 6 shows the progress of the light during the ON operation of the polarization changing panel 40. Fig. 5 and 6 are views showing a state in which the lower polarizing plate 30 and the upper polarizing plate 60 are provided so as to allow light of the same polarization to pass therethrough and the liquid crystal panel 50 is provided with a polarization changing panel 40 in accordance with the driving of the vehicle.

Referring to FIG. 5, only the light of the first polarized light of the arbitrary polarized light provided from the backlight unit 20 passes through the lower polarizer 30. The light of the first polarized light passes through the polarization changing panel 40 in an off state as it is without changing polarized light and enters the liquid crystal panel 50. The first polarized light passes through the liquid crystal panel 50 without changing polarization and passes through the upper polarizer 60.

Referring to FIG. 6, only the light of the first polarized light of the arbitrary polarized light provided from the backlight unit 20 passes through the lower polarizer 30. The light of the first polarized light is converted into the light of the second polarized light orthogonally passing through the polarized light changing panel 40 which is in an on state, and is incident on the liquid crystal panel 50. The light of the second polarized light passes through the liquid crystal panel 50 without changing the polarization, but is blocked, for example, by the upper polarizer 60.

5 and 6, when the lower polarizer 30 and the upper polarizer 60 are arranged so as to pass the light of the same polarization, the image display is performed such that the liquid crystal panel 50 is incident without change in polarization Which is obtained when light is passed through.

In such a liquid crystal display device 10, when the polarized light of the passing light is changed to another polarized light which is orthogonal to the polarized light changing panel 40, even if the light passes through the liquid crystal panel 50 without changing polarization, The light can be blocked by the light source 60.

7 shows a driving principle for preventing color mixing of the liquid crystal display device 10 according to the embodiment of the present invention. 7, the liquid crystal panel 50 and the polarization changing panel 40 in a state of displaying a color image using the light emitted from the second light sources 21b and 23b (light source 2) ).

7, the backlight unit 20 is time-divisionally driven such that the first light sources 21a and 23a (light source 1) and the second light sources 21b and 23b (light source 2) are regularly turned on and off.

The liquid crystal panel 50 includes the first light sources 21a and 23a and the second light sources 21b and 23b while the first light sources 21a and 23a and the second light sources 21b and 23b are driven in a time- The liquid crystal array is changed in units of sub-pixels to drive an image of a desired color to be displayed. The first light sources 21a and 23a and the second light sources 21b and 23b are turned on for a predetermined time in a time division manner in accordance with the liquid crystal arrangement at the moment when the amount of light passing through the upper polarizer 60 reaches a maximum, for example. The first light sources 21a and 23a and the second light sources 21b and 23b are kept in the off state for the rest of the time to suppress color mixing.

The second light sources 21b and 23b are driven during the driving of the backlight 20 (BLU driving) due to the slow motion of the liquid crystal when driven by the high frequency, After the color image is displayed using the light emitted from the light source 2, the first light sources 21a and 23a (light source 1) can not be completely turned off before being turned on. Therefore, color mixing in which the colors of the light emitted from the first light sources 21a and 23a are displayed may occur. For example, when a blue light emitting element is provided as the first light sources 21a and 23a (light source 1) and a yellow light emitting element is provided as the second light sources 21b and 23b (light source 2) Can be incorporated.

However, if the polarization of the light is changed by the polarization changing panel 40 so that the polarized light incident on the liquid crystal panel 50 becomes orthogonal polarized light at the moment when the first light sources 21a and 23a (light source 1) are turned on, 21a, 23a: the light emitted from the light source 1) can be almost blocked by the upper polarizer 60, so that color mixing can be prevented. In Fig. 7, "M" represents a section in which the color mixing prevention operation is performed by the operation of the polarization changing panel 40. [

According to the liquid crystal display device 10 according to the embodiment of the present invention as described above, when a color image is implemented while sequentially driving a plurality of light sources in a time-division manner, a problem of color mixing between colors, Can be improved.

10 ... liquid crystal display device 20 ... backlight unit
21, 23 ... light source arrays 21a, 23a, 115 ... first light source
21b, 23b, 110 ... second light source 25 ... light-
30 ... Lower polarizing plate 40 ... Polarization changing panel
50,130 ... liquid crystal panel 60 ... upper polarizer plate
135 ... liquid crystal layer
137A, 137B, 137C, ...,

Claims (17)

A first light source that emits one color light, and a second light source that emits light including at least a part of the color including a color different from the first light source, wherein the first light source and the second light source are configured to drive the first light source and the second light source in a time- A backlight unit;
A first liquid crystal panel including a color filter arranged to display a color image using light emitted from the backlight unit;
A polarization changing panel adapted to change polarized light of selectively passing light;
A first polarizer disposed between the backlight unit and the polarization changing panel;
And a second polarizer disposed on the liquid crystal panel. The liquid crystal display according to claim 1,
A liquid crystal layer, and an electrode structure that can be driven on a pixel-by-pixel or sub-pixel basis. 3. The polarization-changing panel according to claim 2,
And a second liquid crystal panel having a structure corresponding to the first liquid crystal panel and without a color filter. 2. The polarization-changing panel according to claim 1,
And a second liquid crystal panel having a structure corresponding to the first liquid crystal panel and without a color filter. The liquid crystal display device according to claim 4, wherein the polarization changing panel is provided so as to be driven in units of pixels or sub-pixels corresponding to the first liquid crystal panel. 6. The liquid crystal display according to claim 5, wherein the polarization changing panel changes the polarization of light passing through in the ON operation state, and allows the light passing through in the OFF operation state to pass without changing polarization. 6. The image display apparatus according to claim 5, wherein the polarization changing panel is configured such that, during image display using light emitted from one light source among the first light source and the second light source in pixel units or sub-pixel units, during the operation time of another light source turned on in a time- And turns the polarized light of the light passing through the corresponding pixel or sub-pixel. The liquid crystal display of claim 7, wherein the polarization changing panel operates in an off state for a remaining time so that light passing through the pixel or sub-pixel passes through without change in polarization. 9. The apparatus according to any one of claims 1 to 8, wherein the first light source comprises a plurality of first light sources and the second light source comprises a plurality of second light sources, And the liquid crystal display device is arranged in an array or mixed with each other. 10. The color filter of claim 9, wherein the color filter of the first liquid crystal panel comprises a first sub pixel region for passing the first color light, a second sub pixel region for passing the second color light, The liquid crystal display device comprising: a liquid crystal layer; The liquid crystal display of claim 10, wherein the first color light and the second color light are obtained from light emitted from the second light source. 9. The light-emitting device according to any one of claims 1 to 8, wherein the first light source includes a plurality of first light sources, and the second light source includes a plurality of second light sources, The two light sources include a yellow light emitting element, and the first light source and the second light source are respectively arranged in an array or mixed with each other. 13. The color filter of claim 12, wherein the color filter of the first liquid crystal panel comprises a first sub pixel region for passing first color light, a second sub pixel region for passing a second color light, The liquid crystal display device comprising: a liquid crystal layer; 14. The liquid crystal display of claim 13, wherein the first color light and the second color light are obtained from light emitted from the second light source. 15. The liquid crystal display of claim 14, wherein one of the first color light and the second color light is red light and the other is green light. In order to drive the liquid crystal display device of any one of claims 1 to 6,
Operating the polarization changing panel in an on-state for each pixel or sub-pixel during an operation time of another light source turned on in a time-division manner during image display using light emitted from one light source of the first light source and the second light source;
And changing the polarization of light passing through the corresponding pixel of the polarization changing panel so that light emitted from the other light source is blocked by the second polarizing plate. 17. The method of claim 16, wherein the polarization changing panel operates in an off state for a remaining time to allow light passing through the pixel to pass through without any polarization change.
KR20130115577A 2013-09-27 2013-09-27 Liquid crystal display apparatus and method of driving the same KR20150035248A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107807472A (en) * 2016-09-08 2018-03-16 扬升照明股份有限公司 Light source module group and display device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107807472A (en) * 2016-09-08 2018-03-16 扬升照明股份有限公司 Light source module group and display device
CN107807472B (en) * 2016-09-08 2020-06-16 台湾扬昕股份有限公司 Light source module and display device

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