KR20060112370A - Liquid crystal display device module - Google Patents

Abstract

An LCD is provided to increase a contrast ratio of an image displayed on a screen by inserting a second liquid crystal panel capable of controlling brightness of light and thus controlling brightness of light by each region corresponding to a characteristic of an image displayed on the screen. A support main(127) is formed on a cover bottom(135) and has a quadrangular frame shape. A fluorescent lamp(129) is arranged along a longitudinal direction of the support main, and guides the fluorescent lamp. A backlight unit(120) includes a reflective plate(125) formed sequentially on the support main and a guide plate 123 received on the reflective plate. A second liquid crystal panel(139) is received on the backlight unit, and has fourth and third polarizer(141b,141a) at upper and lower portions, respectively. A first liquid crystal panel(111) is received on the second liquid crystal panel, and includes second and first polarizer(137b,137a) attached to upper and lower portions, respectively. A top cover(113) surrounds edges of the first and second liquid crystal panels, and is assembled and coupled to the support main and the cover bottom.

Description

Liquid crystal display device module

1 is an exploded perspective view of a general liquid crystal display module.

2 is an exploded perspective view of a liquid crystal display module of the edge type backlight unit according to the first embodiment of the present invention.

FIG. 3 is a view schematically illustrating the transmission of light when driving the liquid crystal display module according to the first embodiment of the present invention. FIG.

4 is an exploded perspective view of a liquid crystal display module of the edge type backlight unit according to the second embodiment of the present invention.

5A and 5B are exploded perspective views schematically illustrating a transmission pattern of light of a liquid crystal display according to a second exemplary embodiment of the present invention.

6A to 6C schematically illustrate various pixel sizes and shapes of a second liquid crystal panel.

<Description of the symbols for the main parts of the drawings>

111: first liquid crystal panel 113: top cover

117: printed circuit board 120: backlight unit

121: optical sheet 123: light guide plate

125: reflector 127: support main

129: lamp 131: lamp holder

133: Lamp Guide 135: Cover Bottom

137a and 137b: first polarizing plate and second polarizing plate

139: second liquid crystal panel

141a and 141b: third polarizing plate and fourth polarizing plate

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display, and more particularly, to increasing the contrast ratio of an image quality.

The image realization principle of a general liquid crystal display device uses the optical anisotropy and polarization property of the liquid crystal. The liquid crystal has a thin and long molecular structure and polarization in which the direction of the molecular array changes according to its size when placed in an electric field and an anisotropy having an orientation in the array. It has a nature. The liquid crystal display is an essential component of a liquid crystal panel composed of a pair of transparent insulating substrates, each having a liquid crystal layer interposed therebetween, and having a field generating electrode formed therebetween. By controlling the arrangement direction of the molecules artificially, various images are displayed by using the light transmittance that is changed.

Since the liquid crystal panel does not have a light emitting element, it requires a separate light source. As a result, a backlight unit having a fluorescent lamp is provided on the rear surface to irradiate light toward the front of the liquid crystal panel, thereby realizing an image of identifiable luminance.

1 is an exploded perspective view of a liquid crystal display module of a general edge type backlight unit.

The liquid crystal display module includes a liquid crystal panel 11 and a backlight unit 20 on which a first substrate (not shown) and a second substrate (not shown) are bonded, a support main 27, a cover bottom 35, and a top cover. (13).

That is, as shown in the figure, the backlight unit 20 and the liquid crystal panel 11 are stacked on the upper surface of the support main 27 having a rectangular frame shape, and the shape of the support main 27 is prevented. The cover bottom 35 is coupled along the rear surface of the one open edge of the support main 27, and the top cover 13 bordering the edge of the liquid crystal panel 11 is fixed to the support main 27 to fix all of them. ) And the cover bottom 35 is assembled and fastened.

In this case, a printed circuit board 17 connected through a flexible printed circuit board is connected along at least one side of the liquid crystal panel 11, and the backlight unit 20 supports the backlight unit 20. A lamp 29 including a lamp holder 31 at both ends and arranged along an inner side of an open one edge of the main 27 and a reflecting plate of a white or silver sheet interposed on an upper surface of the support main 27 ( 25, a light guide plate 23 mounted on the reflective plate 25, and a plurality of optical sheets 21 covering the light guide plate 23.

One side of the reflector 25 is provided with a lamp guide 33 for guiding the lamp 29.

At this time, although not shown, the liquid crystal panel 11 is bonded to the first substrate and the second substrate spaced apart by a predetermined interval, and the data wiring and the gate wiring which define a pixel area by crossing each other perpendicularly to one surface of the first substrate. The thin film transistor is configured at the intersection of the two wires.

The pixel region includes a pixel electrode in contact with the thin film transistor.

On the other hand, one surface of the second substrate facing the first substrate is formed of a lattice-like black matrix and a color filter in a region corresponding to the pixel region, and on the front surface of the second substrate including the color filter and the black matrix. A transparent common electrode is constructed.

A liquid crystal layer is formed in the spaced space between the first substrate and the second substrate, a first polarizer 37b is attached to the lower portion of the first substrate, and a second polarizer 37a is disposed on the upper portion of the second substrate. Attached.

In the above-described configuration, when light (not shown) is emitted from the lamp 29 of the backlight unit 20, light is spread widely inside the light guide plate 23 through the light incident part of the light guide plate 23, and thus, a plurality of optical sheets ( A surface light source is provided to the liquid crystal panel 11 through 21. Light (not shown) emitted from the liquid crystal panel 11 is colored in red, green, and blue formed on the second substrate of the liquid crystal panel 11. Filters produce images of different colors.

However, in the conventional liquid crystal display device, although the characteristics of each screen displayed through the liquid crystal panel 11 are different, once the current is applied to the lamp 29 of the backlight unit 20, the same luminance is applied. Will continue.

That is, the backlight unit 20 rapidly changes the screen as in the same image, and irradiates light of the same brightness to the entire screen despite the continuous change in the brightness of each screen area, resulting in an overall contrast ratio of the screen. ) Has a problem of deterioration.

The present invention is to solve the above problems, after separating the area of light incident on the liquid crystal panel through the backlight unit, by selectively adjusting the brightness of the light to enter different brightness to the liquid crystal panel, It is a 1st objective to raise contrast ratio.

Moreover, it is a 2nd objective to acquire clear image quality.

In order to achieve the object as described above, the present invention is covered covertum; A support main formed on the cover bottom and having a rectangular frame shape; A fluorescent lamp arranged along the longitudinal direction of the support main, and a lamp guide for guiding the fluorescent lamp; A backlight unit including a reflection plate sequentially formed on the support main and a light guide plate seated on the reflection plate; A second liquid crystal panel mounted on the backlight unit and having fourth and third polarizers attached to upper and lower portions, respectively; A first liquid crystal panel in which second and first polarizers are respectively attached to upper and lower portions of the second liquid crystal panel; Provided is a liquid crystal display module including a top cover which is edged to the first and second liquid crystal panels and is assembled to the support main and the cover bottom.

Covertum; A support main formed on the cover bottom and having a rectangular frame shape; A fluorescent lamp arranged along the longitudinal direction of the support main, and a lamp guide for guiding the fluorescent lamp; A backlight unit including a reflection plate sequentially formed on the support main and a light guide plate seated on the reflection plate; A second liquid crystal panel mounted on the backlight unit and having a third polarizer attached thereto; A first liquid crystal panel in which second and first polarizers are respectively attached to upper and lower portions of the second liquid crystal panel; Provided is a liquid crystal display module including a top cover which is edged to the first and second liquid crystal panels and is assembled to the support main and the cover bottom.

The backlight unit may further include a plurality of optical sheets mounted on an upper portion of the reflective plate, and one side of the first and second liquid crystal panels may be connected to a printed circuit board through a flexible circuit board. do.

The first and second liquid crystal panels are bonded to each other with the first substrate and the second substrate spaced apart from each other with the liquid crystal interposed therebetween. The first and second liquid crystal panels include data wirings, gate wirings, thin film transistors, and pixel electrodes. And a black matrix, a color filter, and a common electrode on the second substrate of the first liquid crystal panel, wherein light emitted from the backlight unit is first incident on the second liquid crystal panel, and the second liquid crystal The panel may selectively adjust the luminance of light incident from the backlight unit.

The light controlled by the second liquid crystal panel may be incident on the first liquid crystal panel secondly, and the pixel area of the second liquid crystal panel may be the same as or larger than the pixel area of the first liquid crystal panel. And, it can be formed in any shape.

The polarization axes of the first and fourth polarizing plates are in the same direction, and the polarization axes of the second and third polarizing plates are also in the same direction, and the polarization axes of the first and fourth polarizing plates and the second and third polarizing plates are the same. The polarization axes of the polarizing plates are characterized in that they are perpendicular to each other.

In addition, the second and the third polarizing plate is in the same direction, and the first polarizing plate is characterized in that the vertical polarizing plate, the backlight unit is a direct type backlight unit using a cold cathode fluorescent lamp, an external electrode fluorescent lamp and a light emitting diode It characterized in that it further comprises.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

First Embodiment

2 is an exploded perspective view of a liquid crystal display module of the edge type backlight unit according to the first embodiment of the present invention.

The backlight unit 120, the first liquid crystal panel 111, and the second liquid crystal panel 139 are sequentially stacked on the rectangular main frame support main 127 having one edge open, and then the support main 127 is stacked. The cover bottom 135 is coupled along the rear surface of the one open edge of the support main 127 to prevent deformation of the shape, and the edges of the first and second liquid crystal panels 111 and 139 may be fixed to fix the both. The top cover 113 to the frame is assembled and fastened to the support main 127 and the cover bottom 135.

At this time, a printed circuit board 117 connected through a flexible printed circuit board is connected along at least one side of the first and second liquid crystal panels 111 and 139.

The backlight unit 120 is arranged along the length direction inside the opened one edge of the support main 127, and interposed between the lamp 129 including the lamp holder 131 at both ends and the upper surface of the support main 127. It includes a reflector plate 125 of the white or silver sheet, the light guide plate 123 is mounted on the reflector plate 125 and a plurality of optical sheets 121 covering them.

One side of the reflective plate 125 is provided with a lamp guide 133 for guiding the lamp 129.

Although not shown, the first and second liquid crystal panels 111 and 139 are bonded to the first substrate and the second substrate at predetermined intervals, and the first substrates of the first and second liquid crystal panels 111 and 139 are separated from each other. One surface of the data line and the gate line define a pixel area by crossing perpendicularly to each other, and a thin film transistor is formed at the intersection of the two lines. The pixel region constitutes a pixel electrode in contact with the thin film transistor.

On the other hand, one surface of the second substrate facing the first substrate of the first liquid crystal panel 111 is composed of a lattice-like black matrix and a color filter in a region corresponding to the pixel region, and the color filter and the black matrix are formed. A transparent common electrode is formed on the front surface of the second substrate, but the common electrode, the black matrix, and the color filter are not formed on the second substrate facing the first substrate of the second liquid crystal panel 139.

First and second liquid crystal layers are formed in spaced spaces between the first and second substrates of the first and second liquid crystal panels 111 and 139.

In addition, first and third polarizing plates 137b and 141b are attached to the lower portions of the first substrates of the first and second liquid crystal panels 111 and 139, and second and fourth portions are disposed on the upper portions of the second substrates. The polarizing plates 137a and 141a are attached.

The polarizing plate configures polarization axes of the first polarizing plate 137b and the fourth polarizing plate 141a in the same direction, and configures the polarization axes of the second polarizing plate 137a and the third polarizing plate 141b in the same direction. In this case, the polarization axes of the first and fourth polarizing plates 137b and 141a and the polarization axes of the second and third polarizing plates 137a and 141b are formed to be 90 kHz to each other.

3 is a diagram schematically illustrating a state in which light emitted from a backlight unit is incident on the liquid crystal panel when the liquid crystal display module according to the first embodiment of the present invention is driven.

As illustrated, light F emitted from the backlight unit 120 is first incident on the second liquid crystal panel 139, and then secondly incident on the first liquid crystal panel 111.

The light F incident on the second liquid crystal panel 139 is divided by each pixel by each thin film transistor configured for each pixel, so that the brightness and the amount of light F are selectively controlled.

At this time, the light F generated by the backlight unit 120 by the second substrate of the second liquid crystal panel 139 which is not configured to pass through the second liquid crystal panel 139, and has no color ( F) only permeate selectively.

Accordingly, the second luminance is incident on the first liquid crystal panel 111 differently for each pixel, and passes through the second substrate of the first liquid crystal panel 111 having the color filter layer. It will have a wavelength of the color corresponding to the filter.

The light F passing through the color filter layer proceeds to the second polarizing plate 137a of FIG. 2 and appears as an image.

For this reason, the images represented on the screen are expressed with different contrasts.

That is, since the amount of light and luminance of the incident light F are different on the screen even with the same red-based color, they are expressed with different contrasts and have a clearer picture quality. In this case, the pixel formed on the second liquid crystal panel 139 is formed to have a size equal to or larger than a pixel formed on the first liquid crystal panel 111 in order to increase the aperture ratio of the light source.

Second Embodiment

4 is an exploded perspective view of a liquid crystal display module of the edge type backlight unit according to the second embodiment of the present invention.

The backlight unit 220, the first liquid crystal panel 211, and the second liquid crystal panel 239 are sequentially stacked on the top surface of the rectangular main frame support 227 having one edge open, and then the support main 227 is stacked. The cover bottom 235 is coupled along the rear surface of the open edge of the support main 227 to prevent the deformation of the shape of the support main 227, and the edges of the first and second liquid crystal panels 211 and 239 are fixed to fix the both. The top cover 213 to be framed is assembled and fastened to the support main 227 and the cover bottom 235.

In this case, a printed circuit board 217 connected through a flexible printed circuit board is connected along at least one side of the first and second liquid crystal panels 211 and 239.

The backlight unit 220 is arranged along an inner longitudinal direction of one opened edge of the support main 227, and interposes a lamp 229 including a lamp holder 231 at both ends and an upper surface of the support main 227. It includes a reflecting plate 225 of the white or silver sheet, the light guide plate 223 mounted on the reflecting plate 225 and a plurality of optical sheets 221 covering them.

One side of the reflecting plate 225 is provided with a lamp guide 233 for guiding the lamp 229.

In this case, although not illustrated, the first and second liquid crystal panels 211 and 239 are bonded to the first substrate and the second substrate at predetermined intervals, and the first and second liquid crystal panels 211 and 239 may be connected to each other. On one surface of the substrate, a data line and a gate line are defined to cross each other perpendicularly to define a pixel area, and a thin film transistor is formed at an intersection point of the two lines. The pixel region constitutes a pixel electrode in contact with the thin film transistor.

On the other hand, one surface of the second substrate facing the first substrate of the first liquid crystal panel 211 includes a lattice-like black matrix and a color filter in a region corresponding to the pixel region, and the color filter and the black matrix are formed. A transparent common electrode is formed on the front surface of the second substrate, but the common electrode, the black matrix, and the color filter are not formed on the second substrate facing the first substrate of the second liquid crystal panel 239.

First and second liquid crystal layers are formed in spaced spaces between the first and second substrates of the first and second liquid crystal panels 211 and 239.

In addition, the first and second polarizing plates 237a and 237b are attached to the upper and lower portions of the first liquid crystal panel 211, respectively, but the third polarizing plate 241 is attached only to the lower liquid crystal panel 239. do.

The polarizing plate is configured to have the same polarization axis of the second polarizing plate 237a and the third polarizing plate 241, and the polarizing axes of the first and second polarizing plates 237b are 90 °.

5a to 5b schematically illustrate an exploded perspective view of light transmission of the liquid crystal display device.

Although there are various operating modes of the liquid crystal molecules, the present invention will be described using a TN mode (TN) liquid crystal display as an example.

As shown, a first polarizing plate 237b and a second polarizing plate 237a are attached to a lower portion of the first substrate 211b and the upper portion of the second substrate 211a of the first liquid crystal panel 211, respectively. The third polarizer 241 is attached to the lower portion of the first substrate 239b of the second liquid crystal panel 239, and the polarizer is not attached to the upper portion of the second substrate 239a.

The second polarizing plate 237a and the third polarizing plate 241 are configured such that the polarization axes are parallel to each other, and the polarization axes are configured to be 90 kHz to each other.

 As shown in FIG. 5A, when no voltage is applied to the liquid crystal display, the light F that enters the first substrate 239b of the second liquid crystal panel 239 from the outside is the polarization axis of the third polarizer 241. Only light F parallel to the second light passes through the second polarizer 241 and passes through the second liquid crystal layer 250b.

At this time, while passing through the second liquid crystal layer 250b, the light F becomes linearly polarized light in a 90 ° twisted direction with respect to the polarization axis of the third polarizing plate 241. The light F passing through the second liquid crystal layer 250b passes through the second substrate 239a of the second liquid crystal panel 239 as it is.

At this time, the light F selectively transmits only the light F itself, which is not realized by the second liquid crystal panel 239, and the light F incident on the second liquid crystal panel 239 is each pixel. Each of the thin film transistors is divided into regions for each pixel, and the light F having the brightness and the amount of light selectively controlled is incident on the first liquid crystal panel 211.

The light F incident on the first liquid crystal panel 211 passes through the first polarizing plate 237b having the same polarization axis as the second liquid crystal layer 250b and passes through the first liquid crystal layer 250a. Done.

At this time, the light F again has a direction twisted 90 ° with respect to the polarization axis of the first polarizing plate 237b by the first liquid crystal layer 250a. The light F passing through the first liquid crystal layer 250a passes through the second substrate 211a of the first liquid crystal panel 211 as it is, and then passes through the second polarizing plate 237a to obtain a white state ( White state).

That is, the light F has a wavelength of a color corresponding to each color filter while passing through the color filter layer of the second substrate 237a of the first liquid crystal panel 211. Light F formed of a predetermined color by the color filter layer proceeds to the second polarizing plate 237a and is displayed as an image.

As shown in FIG. 5B, when a voltage is applied to the liquid crystal display, an electric field is formed by the voltage. The liquid crystal layer has an optical axis parallel to the polarization axis of the first polarizing plate 237b, but the second and third polarizing plates ( 237a and 241 are formed in a direction perpendicular to the polarization axes.

Therefore, the light F enters the first substrate 239b of the second liquid crystal panel 239 from the outside, passes through the third polarizing plate 241, and then passes through the second liquid crystal layer 250b as it is. The light F passing through the second liquid crystal layer 250b passes through the second substrate 239a of the second liquid crystal panel 239 and then enters the first liquid crystal panel, wherein the polarization axis is the second liquid crystal layer. Since the first polarizing plate 237b twisted by 90 ° on the optical axis of 250b does not pass through, it becomes a black state.

6A through 6C schematically illustrate various pixel sizes and shapes of the second liquid crystal panel 139 according to the first and second exemplary embodiments of the present invention, as shown in FIGS. 6A and 6B. The size of the pixel 140 is larger than or equal to the size of the pixel formed on the first liquid crystal panel 111 of FIG. 2 in order to increase the aperture ratio of the light source.

In addition, as shown in FIG. 6C, the pixel 140 of the second liquid crystal panel 139 may be formed in any shape.

In addition to the liquid crystal display module of the edge type backlight unit according to the first and second embodiments of the present invention, it is also applicable to the liquid crystal display module of the direct type backlight unit using CCFL, EEFL, LED.

The present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

As described above, by inserting a second liquid crystal panel that can adjust the brightness of the light according to the present invention, by adjusting the brightness of the light for each area according to the characteristics of the image to be displayed on the screen, the image expressed on the screen The contrast ratio of the camera is increased, so that a clear picture quality can be obtained.

Claims (12)

Covertum; A support main formed on the cover bottom and having a rectangular frame shape; A fluorescent lamp arranged along the longitudinal direction of the support main, and a lamp guide for guiding the fluorescent lamp; A backlight unit including a reflection plate sequentially formed on the support main and a light guide plate seated on the reflection plate; A second liquid crystal panel mounted on the backlight unit and having fourth and third polarizers attached to upper and lower portions, respectively; A first liquid crystal panel in which second and first polarizers are respectively attached to upper and lower portions of the second liquid crystal panel; Top cover which is bounded by the edge of the first and second liquid crystal panel and assembled to the support main and cover bottom Liquid crystal display module comprising a. Covertum; A support main formed on the cover bottom and having a rectangular frame shape; A fluorescent lamp arranged along the longitudinal direction of the support main, and a lamp guide for guiding the fluorescent lamp; A backlight unit including a reflection plate sequentially formed on the support main and a light guide plate seated on the reflection plate; A second liquid crystal panel mounted on the backlight unit and having a third polarizer attached thereto; A first liquid crystal panel in which second and first polarizers are respectively attached to upper and lower portions of the second liquid crystal panel; Top cover which is bounded by the edge of the first and second liquid crystal panel and assembled to the support main and cover bottom Liquid crystal display module comprising a. The method according to claim 1 and 2, The backlight unit further comprises a plurality of optical sheets mounted on the reflector plate. The method according to claim 1 and 2, And a printed circuit board connected to one side of the first and second liquid crystal panels via a flexible printed circuit board. The method according to claim 1 and 2, The first and second liquid crystal panels are bonded to each other with the first substrate and the second substrate spaced apart from each other with the liquid crystal interposed therebetween. The first and second liquid crystal panels include data wirings, gate wirings, thin film transistors, and pixel electrodes. And a black matrix, a color filter, and a common electrode on the second substrate of the first liquid crystal panel. The method according to claim 1 and 2, The light emitted from the backlight unit is incident to the second liquid crystal panel first, and the second liquid crystal panel may selectively adjust the brightness of the light incident from the backlight unit. The method according to claim 1 and 2, And the light adjusted by the second liquid crystal panel is incident on the first liquid crystal panel. The method according to claim 1 and 2, The pixel area of the second liquid crystal panel may be the same as or larger than the pixel area of the first liquid crystal panel, and may be formed in any shape. The method of claim 1, And the polarization axes of the first and fourth polarizers are in the same direction, and the polarization axes of the second and third polarizers are in the same direction. The method of claim 9, And a polarization axis of the first and fourth polarizing plates and a polarization axis of the second and third polarizing plates are perpendicular to each other. The method of claim 2, And the second and third polarizers are in the same direction and perpendicular to the first polarizer. The method according to claim 1 and 2, The backlight unit further comprises a direct type backlight unit using a cold cathode fluorescent lamp, an external electrode fluorescent lamp and a light emitting diode.

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