KR101335988B1 - Liquid crystal display and control method of the same - Google Patents

Abstract

The present invention relates to a liquid crystal display device and a control method thereof. The liquid crystal display device according to the present invention comprises a liquid crystal shutter glasses; A liquid crystal panel that alternately displays left and right images formed in a predetermined scan direction at predetermined scan periods; A glasses controller for outputting a control signal for opening and closing the liquid crystal shutter glasses in synchronism with the scan period; A light source unit providing light to the liquid crystal panel; And a light source driver configured to supply driving power to the light source unit such that light from the light source unit is emitted to the liquid crystal panel later than the left image and the right image in the scan direction. As a result, a liquid crystal display and a control method thereof, in which image overlap and afterimage are improved, are provided.

LCD shutter glasses, scan drive

Description

Liquid crystal display and its control method {LIQUID CRYSTAL DISPLAY AND CONTROL METHOD OF THE SAME}

The present invention relates to a liquid crystal display device and a control method thereof, and more particularly, to a liquid crystal display device including a liquid crystal shutter glasses and a control method thereof.

Recently, three-dimensional display devices have been developed and used as next-generation display devices following the two-dimensional display devices. The 3D display device alternately displays left and right images using parallax of both eyes, or optically displays left and right images simultaneously.

As a method of simultaneously displaying left and right images, a contact-type method of superimposing a viewing zone forming optical plate on the front of the display panel is mainly used. In the case of alternately forming the left image and the right image, the stereoscopic image is realized by opening and closing the liquid crystal shutter glasses in synchronization with the image while displaying the left image and the right image quickly.

When a liquid crystal panel is used as a display panel among these display devices, there is a problem in that the left image and the right image are overlapped due to the characteristics of the liquid crystal panel which must maintain a voltage for one frame. In the case of the liquid crystal panel, unlike the CRT or other display panels, since the display panel is a hold type display panel, the previous image signal (left image) remains on the display panel before the left image is completely formed after displaying the left image. This causes a problem of failing to provide high quality stereoscopic images because the user is recognized as an image overlap and afterimage.

Accordingly, it is an object of the present invention to provide a liquid crystal display and a control method thereof in which image overlap and afterimage are improved.

The above object is, according to the present invention, a liquid crystal display device comprising: a liquid crystal shutter glasses; A liquid crystal panel that alternately displays left and right images formed in a predetermined scan direction at predetermined scan periods; A glasses controller for outputting a control signal for opening and closing the liquid crystal shutter glasses in synchronism with the scan period; A light source unit providing light to the liquid crystal panel; And a light source driver for supplying driving power to the light source unit such that light from the light source unit is emitted to the liquid crystal panel later than the left image and the right image in the scan direction.

The light source unit may include a plurality of divided areas divided in a direction substantially perpendicular to the scan direction, and the light source driver may supply driving power to the divided areas sequentially in synchronization with the scan period.

In order to prevent image overlap between the frames and afterimages, it is preferable that the light source driving unit block driving power supplied to the light source unit so that light is not emitted to the liquid crystal panel during a predetermined blank period.

In this case, the blank period may be formed between the left image and the right image frame, or the blank period may be formed in the middle of forming one frame.

In order to reduce interference between the divided regions, the light source unit may further include a partition wall formed between the divided regions.

It may further include a light adjusting member provided between the liquid crystal panel and the light source unit to adjust the degree of diffusion of light emitted from the light source unit, the light adjusting member is preferably to reduce the degree of light diffusion to prevent the image overlap. Do.

When the user does not recognize that the left image and the right image are alternately formed, it is preferable that 120 frames are formed per second in the liquid crystal panel so that the user may view the existing 60 Hz image.

On the other hand, the above object is, according to the present invention, in the control method of the liquid crystal display device having a liquid crystal panel for displaying the left image signal and the right image signal alternately every predetermined scan period, and the liquid crystal shutter glasses to open and close the left and right Opening and closing the left and right sides of the liquid crystal shutter glasses in synchronism with the scan period, while displaying an image signal on the liquid crystal panel according to a predetermined scan direction; It may also be achieved by a control method of a liquid crystal display device including supplying light to the liquid crystal panel in the scan direction later than an image signal.

As described above, according to the present invention, there is provided a liquid crystal display device and a control method thereof in which image overlap and afterimage are improved.

Hereinafter, the present invention will be described with reference to the accompanying drawings.

In the various embodiments, the same reference numerals are given to the same constituent elements, and the same constituent elements are exemplarily described in the first embodiment and may be omitted in other embodiments.

1 is a control block diagram of a liquid crystal display according to a first embodiment of the present invention, and FIG. 2 is a simplified perspective view of the liquid crystal display according to the present embodiment. As shown in the drawing, the liquid crystal display device according to the present exemplary embodiment includes a liquid crystal panel 10, a panel driver 20, a liquid crystal shutter glasses 30, an eyeglass control unit 40, a light source unit 50, and a light source driver 60. Include. In addition, the liquid crystal display further includes a light adjusting member 70 provided between the liquid crystal panel 10 and the light source unit 50.

The liquid crystal panel 10 includes a first substrate 10a on which a thin film transistor is formed, a second substrate 10b facing the first substrate 10a, and a liquid crystal formed between both substrates 10a and 10b. It includes a layer (not shown) and consists of a plurality of pixels including a thin film transistor. In the liquid crystal panel 10, gate lines and data lines for driving pixels are formed. The liquid crystal panel 10 typically has a rectangular shape, and an image is formed on the liquid crystal panel 10 along a scan direction corresponding to the short side extending direction of the liquid crystal panel 10. That is, as shown in the image, the images are sequentially displayed on the liquid crystal panel 10 along the scanning direction, and scanned to the last portion of the liquid crystal panel 10 to complete one frame. The liquid crystal panel 10 alternately displays the left image and the right image in units of frames under the control of the panel driver 20. The left image and the right image are displayed on the liquid crystal panel 10 with the same scan period. According to the present embodiment, since the image signal input at 60 Hz is divided into the left image and the right image, the left image and the right image are displayed on the liquid crystal panel 10. 120 frames are formed in one second. That is, the scan period of the image displayed on the liquid crystal panel 10 is 1/120 seconds. Although 120 frames are formed per second in the liquid crystal panel 10, the user recognizes that 60 frames are formed by combining left and right images. If only 60 frames are formed per second while outputting the 60Hz input image by separating the left and right images, the user recognizes that 30 images are displayed per second. When the frame frequency is decreased, the user may recognize the frame change, and there is a problem that the quality of the image is degraded because the continuity of the frame is reduced.

According to another exemplary embodiment, an interpolation frame for interpolating an input video signal may be formed. In this case, 180 or 240 frames may be formed in the liquid crystal panel 10 per second.

The panel driver 20 receives an image signal input from the outside, converts the image signal into an appropriate image signal for displaying a left image and a right image, and applies it to the liquid crystal panel 10. The panel driver 20 drives and controls the liquid crystal panel 10 including a gate driver and a data driver for applying a gate signal and a data signal to the gate line and the data line, and a timing controller for controlling them. The panel driver 20 outputs information on the scan period in which the left image and the right image are formed to the glasses controller 40 and the light source driver 60.

The glasses controller 40 outputs a control signal to the liquid crystal shutter glasses 30 to open and close the left and right sides of the liquid crystal shutter glasses 30 in synchronization with the scan period of the image input from the panel driver 20. The spectacles control unit 40 may include an infrared light emitting device for emitting infrared rays to the liquid crystal shutter glasses 30, wherein the infrared rays correspond to the control signal.

The liquid crystal shutter glasses 30 alternately open and close the left and right images according to a control signal input from the glasses controller 40 so that the user can recognize the left image and the right image alternately. The liquid crystal shutter glasses 30 includes a receiver configured to detect and receive a control signal, and a liquid crystal unit configured to block and transmit an image for a left or right eye according to the received control signal. Both sides of the liquid crystal shutter glasses 30 are alternately opened and closed according to the scan period, and the user can view the 3D stereoscopic image by alternately viewing the left and right images according to the opening and closing of the liquid crystal shutter glasses 30.

The light source unit 50 is provided on the rear surface of the liquid crystal panel 10 to provide light to the liquid crystal panel 10. The light source unit 50 includes a plurality of light sources 50a, a light source circuit board 50b on which the light source 50a is mounted, and a partition wall 50c partitioning the light source circuit board 50b.

The light source unit 50 may include a lamp as a linear light source, a light emitting diode or a nanotube as a point light source, and may include a surface light source that is widely used and developed recently. The light source 50a according to the present embodiment is a light emitting diode, and the light sources 50a are uniformly arranged on the entire rear surface of the liquid crystal panel 10. The light source unit 50 according to the present exemplary embodiment is divided into a plurality of divided regions 51, 52, 53, and 54 of FIG. 3A in a direction substantially perpendicular to the scan direction, that is, a long side direction of the liquid crystal panel 10. . The divided regions 51 to 54 serve as units for receiving driving power from the light source driver 60. The light sources 50a included in one of the divided regions 51 to 54 simultaneously emit light, and the divided regions 51 to 54 are sequentially driven in the scanning direction individually.

The light source circuit board 50b may have a rectangular shape like the liquid crystal panel 10, and a light source driver 60 may be mounted on the rear surface of the light source circuit board 50b. Since a lot of heat is generated in the light emitting diode, the light source circuit board 50b may be made of aluminum having excellent heat transfer rate as a main material. Although not shown, in order to facilitate heat dissipation, the liquid crystal display may further include a heat pipe, a heat dissipation fin, and a cooling fan.

The partition wall 50c partitions between the divided regions 51 to 54 to prevent interference of light emitted from the divided regions 51 to 54. As the independence of the light emitted from each of the divided regions 51 to 54 is maintained, the efficiency of the scanning driving to be described later is improved, thereby reducing the image overlap phenomenon.

The light source driver 60 supplies driving power to the light source unit 50, and sequentially supplies driving power to the divided regions 51 to 54 in synchronization with the scan period. That is, only one divided area 51 to 54 emits light at a time, and the remaining divided areas 51 to 54 are not driven. As such, when the light source unit 50 is controlled to emit light only at a predetermined portion of the light source unit 50 instead of all regions, the afterimage and image overlap of the liquid crystal panel 10 are improved. There is. That is, a black condition in which light is not provided to the hold type liquid crystal panel 10 is implemented to implement an impulsive type such as CRT. Since the image is not displayed in the portion where the light is not supplied to the liquid crystal panel 10, the image overlapping of the existing image is improved and light is diffused to an unnecessary area.

3A to 3F illustrate a scanning method of the liquid crystal panel 10 and the light source unit 50 according to the present embodiment, and FIG. 4 is a timing diagram for explaining the light emission form of the light source unit. A method of supplying driving power to the light source unit 50 will be described with reference to the drawings. 3A, 3C, and 3E illustrate a process of scanning an image on the liquid crystal panel 10, and FIGS. 3B, 3D, and 3F correspond to the divided regions 51 to 54 of the light source unit 50. It shows the process being scanned. As shown, the light source unit 50 is divided into the first divided regions 51 to the fourth divided regions 54, that is, the four divided regions 51 to 54, and includes a plurality of point light sources 50a. .

First, as shown in FIG. 3A, while the image is scanned to the first image region 11 corresponding to about one quarter of the liquid crystal panel 10, any divided regions 51 to 54 of the light source unit 50 may be removed as shown in FIG. 3B. It is not driven. Then, when the image is scanned to the second image area 12 corresponding to about 1/2 as shown in FIG. 3c, the first divided area 51 is driven as shown in FIG. 3d. The liquid crystal layer of the liquid crystal panel 10 maintains an image signal of an image corresponding to the first image region 11 until one frame is completed, and such an image is generated when the first division region 51 is driven. Will be acknowledged by the user. When the image is scanned up to the third image region 13 as shown in FIG. 3E, the second division region 52 corresponding to the second image region 12 is driven as shown in FIG. 3F.

4, the left image and the right image are alternately displayed on the liquid crystal panel 10 for each scan period T, and each of the divided regions 51 to 54 is formed for T / 4. Are driven sequentially. When the image is scanned for the first time, light is not provided during the first T / 4 because there are no divided regions 51 to 54 driven as shown in FIG. 3B. Then, when the second to fourth image areas are sequentially scanned, the first divided area to the third divided area are sequentially scanned along the scanned image area.

When the scan period T of the left image is finished and the first image region of the right image is continuously scanned, the fourth divided region 54 is driven.

In summary, the light source driver 60 supplies driving power to the light source unit 50 so that light is scanned later than an image displayed on the liquid crystal panel 10. Therefore, a problem such as an image overlapping with the left image remaining in the liquid crystal panel 10 while the right image is scanned after the left image is conventionally generated does not occur. Since the light from the light source unit 50 is scanned later than the image and the image is partially displayed instead of the entirety, the left image and the right image cannot be viewed simultaneously.

The light adjusting member 70 is provided between the liquid crystal panel 10 and the light source unit 50 and includes a protective film 71, a prism film 73, and a diffusion control plate 75.

The protection film 71 located at the top protects the prism film 73 which is weak to scratches.

The prism film 73 is formed in a triangular prism-shaped prism on the upper surface with a constant arrangement. The prism film 73 collects light passing through the diffusion control plate 75 in a direction perpendicular to the arrangement plane of the upper liquid crystal panel 10. Two prism films 73 are usually used, and the micro prisms formed on each prism film 73 have a predetermined angle. The light passing through the prism film 73 proceeds almost vertically to provide a uniform luminance distribution. If necessary, a reflective polarizing film may be used together with the prism film 73, and only the reflective polarizing film may be used without the prism film 73.

The diffusion control plate 75 is made of a coating layer comprising a bead-shaped beads formed on the base plate and the base plate. The diffusion control plate 75 controls the degree of diffusion of the light supplied from the light source 50a, and in the present embodiment reduces the diffusion of light. That is, the light emitted from the specific partitions 51 to 54 prevents excessive diffusion of light so that the light does not affect the other partitions 51 to 54. The diffusion control plate 75 may be designed to diffuse the light emitted from one of the divided regions 51 to 54 to make the luminance uniform.

5 is a timing diagram for describing a light emission form of a light source unit according to a second embodiment of the present invention, and FIG. 6 is a control flowchart illustrating a control method of the liquid crystal display device according to the present embodiment.

As shown, the light source unit 50 according to the present embodiment does not emit light to the liquid crystal panel 10 between the frame in which the left image and the right image are displayed. The left image and the right image are typically scanned by the liquid crystal panel 10 for 4T / 5, which is shorter than the scan period T in which one frame is formed, and maintains the formed image for the remaining T / 5. The partitions 51 to 54 are sequentially driven for T / 5 in synchronization with the scanning of the image, and are not driven during the last T / 5.

That is, the liquid crystal display according to the present exemplary embodiment has a blank section B in which an image is not displayed on the liquid crystal panel 10 for a predetermined time after one frame in which an image is displayed and before a continuous frame is formed. The blank section B is implemented through the light source unit 50. The light source driver 50 does not supply driving power to the light source unit 60 during the blank period B. FIG. Through the blank period B, afterimages occurring in the liquid crystal panel 10 may be prevented, and problems caused by light diffused into unnecessary areas may be reduced.

In the present embodiment, light is provided from the divided regions 51 to 54 corresponding to the scanned image. However, light may be provided after the scanned image as in the above-described embodiment. Alternatively, the blank period B may be formed at the beginning of one frame rather than after all of the images are formed. The time at which the blank section B is formed, the time at which the blank section B is maintained, and the scanning scheme of the divided regions 51 to 54 may be freely set by those skilled in the art.

Referring to FIG. 6, the control method of the liquid crystal display according to the present embodiment is summarized as follows. First, the left image signal and the right image signal are alternately displayed on the liquid crystal panel 10 in every scan period along the scanning direction, and the left and right sides of the liquid crystal shutter glasses 40 are opened and closed (S10).

At this time, the liquid crystal shutter glasses 40 are opened and closed in synchronization with the scan period, and when the left image signal is displayed, the left side of the liquid crystal shutter glasses 40 is opened, and when the right image signal is displayed, the liquid crystal shutter glasses 40 ) Is opened to the right. 120 or more frames may be formed in the liquid crystal panel 10 per second.

Subsequently, the scan direction is sequentially supplied to the image regions 11 to 14 of the liquid crystal panel 10 sequentially after the image signal (S20). The light source unit 50 is divided into divided regions 51 to 54 corresponding to the image regions 11 to 14, and is scanned by the liquid crystal panel 10 by controlling driving power supplied to the divided regions 51 to 54. Provide light.

The light source driver 60 blocks the light emitted to the liquid crystal panel 10 during the blank period B between the left image signal and the right image signal frame (S30). An afterimage of the liquid crystal panel 10 is prevented due to the blank period B in which light is not provided.

7 is a timing diagram of a liquid crystal display according to a third embodiment of the present invention. As shown, the light source driver 60 according to the present embodiment forms a blank section (B) in the middle of the frame is formed. The image signal is displayed in units of frames according to the scan period T, and light is blocked for a predetermined time during the scan period T while scanning the liquid crystal panel 10 after the image signal. That is, the time when the blank section B is formed is not limited to a specific time, and it is also possible that the blank section B is present more than once while one frame is formed.

The number of the divided regions 51 to 54 is not limited to the above four, and may be variously changed in consideration of the size of the liquid crystal panel 10, the scan speed of the light source driver 60, the contrast ratio, and the luminance.

In addition, the left image and the right image are used to name consecutive adjacent images, and do not refer to an image in a specific direction.

The present invention scans and drives the light source unit 50 and inserts a blank section B in order to prevent image overlap and afterimage in a liquid crystal display including a liquid crystal shutter glasses.

Although some embodiments of the invention have been shown and described, it will be apparent to those skilled in the art that the embodiments may be modified without departing from the spirit or spirit of the invention. . The scope of the invention will be determined by the appended claims and their equivalents.

1 is a control block diagram of a liquid crystal display according to a first embodiment of the present invention,

2 is a simplified perspective view of a liquid crystal display according to a first embodiment of the present invention;

3A to 3F are views for explaining a scanning method of a liquid crystal panel and a light source unit according to the first embodiment of the present invention;

4 is a timing diagram of a light source unit according to a first embodiment of the present invention;

5 is a timing diagram of a light source unit according to a second embodiment of the present invention;

6 is a control flowchart for explaining a control method of a liquid crystal display according to a second exemplary embodiment of the present invention.

7 is a timing diagram of a light source unit according to a third embodiment of the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

10: liquid crystal panel 20: panel driver

30: liquid crystal shutter glasses 40: glasses control unit

50: light source unit 60: light source driving unit

70: light control member

Claims (12)

In the liquid crystal display device, Liquid crystal shutter glasses; A liquid crystal panel that alternately displays left and right images formed in a predetermined scan direction at predetermined scan periods; A glasses controller for outputting a control signal for opening and closing the liquid crystal shutter glasses in synchronism with the scan period; A light source unit providing light to the liquid crystal panel and including a plurality of divided regions; A light source that sequentially supplies driving power to the plurality of divided regions sequentially so that light from the light source unit is emitted to the liquid crystal panel later than the left image and the right image with respect to the plurality of divided regions along the scanning direction Liquid crystal display device comprising a drive unit. delete The method of claim 1, And the light source driver blocks driving power supplied to the light source unit such that light is not emitted to the liquid crystal panel during a predetermined blank period. The method of claim 3, And the blank period is formed between the left image frame and the right image frame. The method of claim 3, And the blank period is formed in the middle of forming one frame. The method of claim 1, And the light source unit further comprises a partition formed between the divided regions. The method of claim 1, And a light adjusting member disposed between the liquid crystal panel and the light source unit to adjust a degree of diffusion of light emitted from the light source unit. The method of claim 1, And 120 frames are formed per second on the liquid crystal panel. In a control method of a liquid crystal display device having a liquid crystal panel divided into predetermined image regions by displaying a left image signal and a right image signal alternately at predetermined scan periods, and a liquid crystal shutter eyeglasses that are opened and closed at right and left, Opening and closing the left and right sides of the liquid crystal shutter glasses in synchronism with the scan period, while displaying an image signal on the liquid crystal panel in a predetermined scan direction; And sequentially supplying light sequentially to the predetermined image area along the scan direction subsequent to the image signal. delete 10. The method of claim 9, And blocking light emitted to the liquid crystal panel during a predetermined blank period. 10. The method of claim 9, And 120 frames are formed per second on the liquid crystal panel.

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