KR102526486B1 - Liquid crystal display device and LED assembly - Google Patents

Abstract

In the present invention, a warm white LED that emits yellowish white, that is, the first LED, and a cool white LED that emits blueish white that emits a higher color temperature, that is, a second LED, are used. to operate in the off state. Accordingly, it is possible to maximize the reduction in total LED power consumption during normal mode driving and reader mode driving.
Furthermore, a yellow phosphor pattern corresponding to the second LED is formed under the light receiving part of the light guide plate on a reflector or a PCB on which the LED is mounted, or an opening exposing the polyimide substrate of the PCB having similar light characteristics in place of the yellow phosphor pattern. A pattern can be formed on the coverlay film of the PCB. Accordingly, the white color deviation in the light entrance portion of the light guide plate in front of the second LED can be minimized, thereby improving the Mura phenomenon and implementing a narrow bezel.

Description

Liquid crystal display device and LED assembly

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device capable of reducing power consumption of an LED.

As the information society develops, the demand for display devices for displaying images is increasing in various forms. Recently, liquid crystal display devices (LCDs), plasma display devices (PDPs), organic Various flat display devices such as organic light emitting diodes (OLEDs) are being utilized.

Among these flat panel display devices, liquid crystal display devices are widely used because of their advantages of miniaturization, light weight, thinness, and low power consumption.

A light emitting diode (LED) is widely used as a light source of a liquid crystal display device, and a white LED emitting white light is generally used.

Meanwhile, a liquid crystal display device operating in a so-called reader mode, which is an image display mode capable of displaying a screen having a paper texture, in addition to a normal mode, which is a general image display mode, is being used. To this end, a warm white LED having a yellowish characteristic is used as a white LED.

1 is a plan view schematically showing a warm white LED and a light guide plate of a conventional liquid crystal display device, and FIG. 2 is a diagram showing an example of a normal mode screen and a reader mode screen of a conventional liquid crystal display device.

Referring to FIG. 1 , a plurality of warm white LEDs 26 are disposed along the light incident surface of the light guide plate 23 . At this time, by turning on all the warm white LEDs 26 and adjusting the R (red), G (green), and B (blue) colors on the liquid crystal panel, the normal mode and the reader mode are implemented. A normal mode screen and a reader mode screen as shown in FIG. 2 may be displayed.

However, the warm white LED 26 has a high driving voltage due to its characteristics, so power consumption is very high. Therefore, in the conventional liquid crystal display device using the warm white LED 26, power consumption increases.

An object of the present invention is to provide a method for reducing power consumption of LEDs in a liquid crystal display device driven in a normal mode and a reader mode.

In order to achieve the above object, the present invention provides a liquid crystal panel, a light guide plate under the liquid crystal panel, and disposed along a light incident surface of the light guide plate, and emits yellow white and blue white light, respectively. Provided is a liquid crystal display device including first and second LEDs, and a yellow phosphor pattern located under the light input portion of the light guide plate to correspond to the second LED.

Here, a reflector under the light guide plate may be further included, and the yellow phosphor pattern may be provided on the reflector.

The first and second LEDs may further include a PCB mounted on a side surface positioned on one side of the light emitting surface, and the yellow phosphor pattern may be provided on a portion of the PCB located below the light guide plate.

The PCB includes a substrate and a coverlay film covering an upper surface of the substrate, and the yellow phosphor pattern may be provided on the coverlay film or in an opening pattern of the coverlay film.

The coverlay layer may have a white color.

In another aspect, the present invention provides a liquid crystal panel, a light guide plate under the liquid crystal panel, and first and second LEDs disposed along the light incident surface of the light guide plate and emitting yellowish white and blueish white light, respectively. , The first and second LEDs include a PCB mounted on a side surface positioned on one side of a light emitting surface, the PCB includes a substrate made of polyimide and a coverlay film covering an upper surface of the substrate, and the mouth of the light guide plate A liquid crystal display device having an opening pattern positioned corresponding to the second LED is provided in the cover layer under the miner.

The coverlay layer may have a white color.

In another aspect, the present invention provides first and second LEDs respectively emitting yellowish white and bluish white, and a PCB mounted on the side where the first and second LEDs are located on one side of the light emitting surface Including, the PCB portion located in front of the second LED, provided with a yellow phosphor pattern or provided with an opening pattern for exposing a substrate made of polyimide of the PCB to the outside provides an LED assembly.

The PCB may include a coverlay film covering an upper surface of the substrate, and the yellow phosphor pattern may be positioned on the coverlay film or within an opening pattern of the coverlay film.

The PCB may include a coverlay film covering an upper surface of the substrate, and an opening pattern exposing the substrate to the outside may be provided on the coverlay film.

The coverlay layer may have a white color.

In the present invention, a warm white LED that emits yellowish white, that is, the first LED, and a cool white LED that emits blueish white that emits a higher color temperature, that is, a second LED, are used. operate in the off state. Accordingly, it is possible to maximize the reduction in total LED power consumption during normal mode driving and reader mode driving.

Furthermore, a yellow phosphor pattern corresponding to the second LED is formed under the light receiving part of the light guide plate on a reflector or a PCB on which the LED is mounted, or an opening exposing the polyimide substrate of the PCB having similar light characteristics in place of the yellow phosphor pattern. A pattern can be formed on the coverlay film of the PCB. Accordingly, the white color deviation in the light entrance portion of the light guide plate in front of the second LED can be minimized, thereby improving the Mura phenomenon and implementing a narrow bezel.

1 is a plan view schematically showing a warm white LED and a light guide plate of a conventional liquid crystal display device.
2 is a diagram showing an example of a normal mode screen and a reader mode screen of a conventional liquid crystal display device;
3 and 4 are exploded perspective views and cross-sectional views schematically showing a liquid crystal display device according to a first embodiment of the present invention, respectively.
5 and 6 are diagrams schematically illustrating light emitting states of first and second LEDs in normal mode and reader mode operation of the liquid crystal display according to the first embodiment of the present invention, respectively.
7 is a plan view schematically illustrating an LED of a liquid crystal display device according to a second embodiment of the present invention and a reflector on which a yellow phosphor pattern is formed.
8 and 9 are diagrams schematically illustrating light emitting states of first and second LEDs in normal mode and reader mode operation of the liquid crystal display according to the second embodiment of the present invention, respectively.
10 is a plan view schematically showing an LED assembly of a liquid crystal display according to a third embodiment of the present invention.
11 is a cross-sectional view schematically showing a cross-sectional structure of a PCB on which an LED according to a third embodiment of the present invention is mounted.
12 is a schematic cross-sectional view of a backlight unit of a liquid crystal display according to a third embodiment of the present invention.
13 and 14 are a plan view and a cross-sectional view schematically illustrating an LED assembly of a liquid crystal display device according to a fourth embodiment of the present invention, respectively.

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

<First Embodiment>

3 and 4 are exploded perspective views and cross-sectional views schematically showing a liquid crystal display device according to a first embodiment of the present invention, respectively.

As shown, the liquid crystal display device 100 according to the embodiment of the present invention includes a liquid crystal panel 110, a backlight unit 120, a guide panel 130, a top case 140, and a bottom cover 150. It may include, these components are combined and fixed to each other to constitute a modular liquid crystal display device (100).

Here, for convenience of description, directions in the drawings may be defined. The direction of the display surface of the liquid crystal panel 110 is referred to as forward or upward (or upward), and the opposite direction is referred to as backward or downward (or downward). .

The liquid crystal panel 110 is configured to display an image, and includes first and second substrates 112 and 114 bonded together when facing each other and a liquid crystal layer (not shown) interposed between the two substrates 112 and 114.

Although not specifically shown, on the inner surface of the first substrate 112, which is called a lower substrate or an array substrate, pixels are defined by crossing a plurality of gate wires and data wires, and each pixel has a thin film transistor connected to a corresponding gate wire and data wire. and a pixel electrode connected to the thin film transistor may be formed.

And, on the inner surface of the second substrate 114, which is called an upper substrate or a color filter substrate as a counter substrate facing the first substrate 112, a color filter pattern corresponding to each pixel and a color filter pattern are wrapped around the gate wiring and A black matrix may be formed to cover non-display elements such as data wires and thin film transistors.

At this time, all types of liquid crystal panels may be used as the liquid crystal panel 110, for example, all types of liquid crystal panels such as IPS type, AH-IPS type, TN type, VA type, and ECB type may be used. Here, when the IPS method or the AH-IPS method is used, a common electrode forming a lateral electric field together with the pixel electrode may be formed on the first substrate 112 .

In addition, an alignment film may be formed at the interface between the first and second substrates 112 and 114 and the liquid crystal layer to determine the initial molecular alignment direction of the liquid crystal, and to prevent leakage of the liquid crystal layer filled between the first and second substrates 112 and 114. For this purpose, seal patterns may be formed along the edges of the two substrates 112 and 114 .

In addition, a polarizing plate selectively transmitting a specific polarized light may be attached to the outer surface of each of the first and second substrates 112 and 114 .

In addition, along at least one edge of the liquid crystal panel 110, a printed circuit board is connected via a connecting member such as a flexible circuit board or a tape carrier package, so that it is bent to the rear surface of the bottom cover 150 in the modularization process so as to be in close contact with it. can

A backlight unit 120 is disposed behind the liquid crystal panel 110 configured as described above.

The backlight unit 120 may include an LED assembly 126, a white or silver reflector 125, a light guide plate 123 seated on the reflector 125, and an optical sheet 121 on the light guide plate 123. can

The LED assembly 126 functions as a light source of the backlight unit 120 and includes a plurality of LEDs 127 facing the light incident surface of the light guide plate 123 and a PCB on which the plurality of LEDs 127 are mounted spaced apart at regular intervals ( 128) may be included.

A plurality of LEDs 127 correspond to LEDs 127 emitting white light. The light emitting surface of the plurality of LEDs 127 faces the light incident surface of the light guide plate 123 . In addition, the light emission range of the LEDs 127 based on the plane of the light guide plate 123 is spread on both sides, so that the light emission ranges of the adjacent LEDs 127 overlap inside the light guide plate 123 .

In particular, the plurality of LEDs 127 may include first and second LEDs 127a and 127b emitting light of first and second white, which are different white colors, respectively.

Here, the first LED 127a is a warm white LED 127a emitting light of a relatively low color temperature, that is, yellowish white, and the second LED 127b is a relatively high color temperature white LED 127a. It is a cool white LED 127b that emits cool white, that is, bluish white.

The first and second LEDs 127a and 127b may be alternately arranged. In this regard, for example, it may be alternately arranged one by one, but is not limited thereto, and other types of alternating arrangement structures are possible. As an example of another arrangement structure, two or more first LEDs 127a (or two or more second LEDs 127b) and one or more second LEDs 127b (or one or more first LEDs 127a) are alternately arranged. It may have a layout structure of the form.

As such, in the present embodiment, the first LED 127a emitting warm white first white and the second LED 127b emitting cool white second white having a higher color temperature are used together, thereby reducing total consumption of LED 127. power can be reduced.

In this regard, since the driving voltage of the second LED 127b is lower than that of the first LED 127a and the power consumption is also smaller than that of the first LED 127a, both the first and second LEDs 127a and 127b are turned on and driven. The power consumption of all LEDs 127 can be reduced during normal mode driving.

Furthermore, since the second LED 127b operates to be in an off state and not to emit light when driven in reader mode, power consumption of all LEDs 127 can be reduced even when driven in reader mode.

As such, since the first LED 127a emitting warm white and the second LED 127b emitting cool white are used, the effect of reducing power consumption can be maximized.

The light guide plate 123 into which the light emitted from the plurality of LEDs 127 described above is incident is transmitted to a wide area of the light guide plate 123 while the light incident from the LEDs 127 travels through the light guide plate 123 by multiple total reflections. It is possible to provide a uniform surface light to the liquid crystal panel 110 by spreading it evenly.

The reflector 125 is positioned behind the light guide plate 123 and serves to reflect the light passing through the rear surface of the light guide plate 123 toward the liquid crystal panel 110 to improve luminance.

The optical sheet 121 positioned on the light guide plate 123 may include, for example, a diffusion sheet and a light collecting sheet, and diffuses and collects the light emitted from the light guide plate 123 to be processed into the liquid crystal panel 110 with high quality. It can act to make more uniform surface light incident.

The liquid crystal panel 110 and the backlight unit 120 configured as above can be modularized through the guide panel 130, the bottom cover 150, and the top case 140.

The guide panel 130 may be formed in a square frame shape surrounding side surfaces of the liquid crystal panel 110 and the backlight unit 120 . The liquid crystal panel 110 may be seated on the guide panel 130 . In this case, the liquid crystal panel 110 may be attached to the upper surface of the guide panel 130 through an adhesive member such as double-sided adhesive tape.

The bottom cover 150 protects and supports the rear surface of the backlight unit 120 surrounded by the guide panel 130 . The bottom cover 150 may include a plate-shaped base on which the backlight unit 120 is seated and a sidewall portion vertically bent upward from a corner of the base, and an internal accommodation space defined by the base and the sidewall. To accommodate the backlight unit 120.

The top case 140 may have a square frame shape covering the edge of the liquid crystal panel 110 .

The above guide panel 130 , bottom cover 150 , and top case 140 are assembled and fastened so that they can be modularized together with the liquid crystal panel 110 and the backlight unit 120 .

Hereinafter, operations in the normal mode and the reader mode of the liquid crystal display device 100 having the configuration described above will be described in detail with further reference to FIGS. 5 and 6 .

5 and 6 are diagrams schematically showing light emitting states of first and second LEDs in normal mode and reader mode operation of the liquid crystal display device according to the first embodiment of the present invention, respectively. 5 and 6 mainly show the first and second LEDs and the light guide plate positioned in front thereof for convenience of description.

Referring to FIG. 5 in relation to the normal mode, in the normal mode, both the first LED 127a, which is a warm white LED, and the second LED 127b, which is a cool white LED, are turned on and emit light.

Accordingly, the first white light emitted from the first LED 127a and the second white light emitted from the second LED 127b are incident into the light guide plate 123 through the incident surface of the light guide plate 123, and the light guide plate 123 ), color mixing of the first and second whites occurs inside, so that white suitable for general mode display can be generated. That is, in the light guide plate 123, the first white, which is yellowish white, and the second white, which is blueish white, are rotted so that white suitable for normal mode display can be generated.

The white generated by the color mixing of the first and second whites is transmitted to the liquid crystal panel 110 above the light guide plate 123 so that an image display in a normal mode can be preferably performed.

Meanwhile, referring to FIG. 6 in relation to the reader mode, in the reader mode, the first LED 127a, which is a warm white LED, is turned on and emits light, and the second LED 127b, which is a cool white LED, is turned off. and become non-luminous.

Accordingly, the first white light emitted from the first LED 127a is incident into the light guide plate 123 through the incident surface of the light guide plate 123, and the second white light from the second LED 127b penetrates the light guide plate 123. don't get hired That is, only first white, which is yellowish white suitable for reader mode display, is incident on the inside of the light guide plate 123 .

This first white is transferred to the liquid crystal panel 110 above the light guide plate 123 so that the image display in the reader mode can be preferably performed.

As described above, according to the present embodiment, the first LED 127a that emits warm white first white light and the second LED 127b that emits cool white second white light having a higher color temperature are mixed and configured LED 127 is used, and the second LED 127b having low power consumption is operated in an off state in the reader mode.

Accordingly, when driving in the normal mode, power consumption of all LEDs 127 can be reduced as the second LED 127b consuming low power together with the first LED 127a emits light, and when driving in reader mode, the second LED ( 127b) is in a non-emission state, so that power consumption of all LEDs 127 can be minimized, and as a result, the effect of reducing power consumption can be maximized.

<Second Embodiment>

The liquid crystal display device according to the second embodiment of the present invention has a yellow phosphor pattern formed on the reflector in the liquid crystal display device of the first embodiment, and will be described in detail below. On the other hand, for convenience of description, detailed descriptions of components identical and similar to those of the first embodiment may be omitted below.

7 is a plan view schematically illustrating an LED of a liquid crystal display device according to a second embodiment of the present invention and a reflector on which a yellow phosphor pattern is formed, and FIGS. 8 and 9 are respectively a liquid crystal display device according to a second embodiment of the present invention. It is a diagram schematically showing the light emitting states of the first and second LEDs during normal mode and reader mode operation of .

7 to 9, in the liquid crystal display according to the present embodiment, as a portion of the reflector 125 near the LED 127, a yellow phosphor is placed on the upper surface of the reflector portion below the light entrance portion 123a of the light guide plate 123. A pattern 210 may be formed. In particular, the yellow fluorescent paint pattern 210 may be formed in a corresponding position facing the second LED 127b in front of the second LED 127b emitting bluish white. Here, the light entrance portion 123a of the light guide plate 123 may correspond to a portion located within a bezel, which is a non-display area of the liquid crystal display device, that is, on the side of the light guide plate 123 where the LED 127 is located. It may be a part defined even to the display area of the liquid crystal display device.

The yellow phosphor pattern 210 may be formed to have various shapes. In this embodiment, a case having a substantially rectangular shape in plan view is illustrated as an example, and other shapes may be optimized as needed.

When the yellow phosphor pattern 210 is disposed on the reflector 125 corresponding to the front of the second LED 127b, the light entrance portion 123a of the light guide plate in front of the second LED 127b and the yellow phosphor pattern 210 around it As a result, yellowish white comes into existence. In this case, white color deviation occurs around the light guide plate 123a along the arrangement direction of the LEDs 127 (ie, the light guide plate 123 lengthwise direction), causing mura. can be improved.

In this regard, referring again to FIG. 5 of the first embodiment, when driving in the normal mode, yellowish white emitted from the first LED 127a and emitted from the second LED 127b in the vicinity of the light guide plate 123a Therefore, a white color deviation occurs between blueish white and yellowish white along the arrangement direction of the LEDs 127 around the light input portion 123a.

Accordingly, when the bezel width of the liquid crystal display device is narrow, a white color deviation is observed from the outside and is recognized as a Mura phenomenon. In order to solve this mura vision problem, it is necessary to increase the width of the bezel to cover the area where the white color deviation occurs. In this way, a narrow bezel cannot be implemented.

On the other hand, in the second embodiment, the yellow phosphor pattern 210 is formed at a position corresponding to the second LED 127b of the reflector 125 .

Accordingly, yellowish white by the yellow phosphor pattern 210 is incident on and near the light guide plate 125a in front of the second LED 127b, thereby minimizing the white color deviation in the arrangement direction of the LEDs 127. do.

Therefore, it is possible to improve the Mura phenomenon due to the white color deviation, and furthermore, it is possible to effectively implement a narrow bezel.

Hereinafter, operations in the normal mode and the reader mode of the liquid crystal display having the above configuration will be described in detail with reference to FIGS. 8 and 9 .

Referring to FIG. 8 , in the normal mode, both the first LED 127a, which is a warm white LED, and the second LED 127b, which is a cool white LED, are turned on and emit light.

Accordingly, the first white light emitted from the first LED 127a and the second white light emitted from the second LED 127b are incident into the light guide plate 123 through the incident surface of the light guide plate 123, and the light guide plate 123 ), color mixing of the first and second whites occurs inside, so that white suitable for general mode display can be generated. That is, in the light guide plate 123, the first white, which is yellowish white, and the second white, which is blueish white, are rotted so that white suitable for normal mode display can be generated.

The white generated by the color mixing of the first and second whites is transmitted to the liquid crystal panel 110 above the light guide plate 123 so that an image display in a normal mode can be preferably performed.

Furthermore, as the yellow phosphor pattern 210 is formed on the reflector 125 in front of the second LED 127b, it is possible to improve white color deviation in the light input portion.

Meanwhile, referring to FIG. 9 , in the reader mode, the first LED 127a, which is a warm white LED, is turned on and emits light, and the second LED 127b, which is a cool white LED, is turned off and does not emit light.

Accordingly, the first white light emitted from the first LED 127a is incident into the light guide plate 123 through the incident surface of the light guide plate 123, and the second white light from the second LED 127b penetrates the light guide plate 123. don't get hired That is, only first white, which is yellowish white suitable for reader mode display, is incident on the inside of the light guide plate 123 .

This first white is transferred to the liquid crystal panel 110 above the light guide plate 123 so that the image display in the reader mode can be preferably performed.

<Third Embodiment>

In the liquid crystal display device according to the third embodiment of the present invention, the yellow phosphor pattern is formed on the PCB on which the LED is mounted in the liquid crystal display device of the first embodiment, and the yellow phosphor pattern is formed on the PCB instead of the reflector of the second embodiment. , which will be described in more detail below. Meanwhile, for convenience of description, detailed descriptions of the same or similar components to those of the first embodiment or the second embodiment may be omitted below.

10 is a plan view schematically showing an LED assembly of a liquid crystal display device according to a third embodiment of the present invention, and FIG. 11 is a schematic cross-sectional structure of a PCB on which an LED according to a third embodiment of the present invention is mounted. 12 is a cross-sectional view schematically illustrating a backlight unit of a liquid crystal display device according to a third embodiment of the present invention.

10 to 12, in the liquid crystal display device according to the present embodiment, a yellow phosphor pattern 210 is formed on the upper surface of the PCB 128 on which the LED 127 is mounted. In particular, the yellow phosphor pattern 210 It is located on the upper surface of the PCB 128 in front of the second LED 127b emitting blueish white.

Here, the PCB 128 is configured such that the side of the LED 127 is mounted on its upper surface. That is, the LED 127 is mounted on the upper surface of the PCB 128 on the side located on one side of the light emitting surface of the LED 127 facing the light incident surface of the light guide plate 123 . As shown in FIG. 12 , such a PCB 128 is disposed so that the portion where the yellow phosphor pattern 210 is formed is located below the light entrance portion of the light guide plate 123 .

Meanwhile, as in this embodiment, a structure in which the LED 127 is mounted on the PCB 128 from its side may be referred to as a so-called side view structure. On the other hand, as shown in the first embodiment above, a structure in which the LED 127 is mounted on the PCB 128 from its rear surface may be referred to as a so-called top view structure.

Here, in the side view structure of the present embodiment, since the PCB 128 is disposed in a direction parallel to the plane of the liquid crystal display device, an advantage of reducing the thickness of the liquid crystal display device compared to the top view structure can be implemented. Meanwhile, in the first and second embodiments, both a top-view structure and a side-view structure may be adopted.

Referring to FIG. 11 in relation to the cross-sectional structure of the PCB 128 of this embodiment, the PCB 128 includes a substrate 128a and a coverlay film 128b covering the top surface of the substrate 128a. and a yellow phosphor pattern 210 may be formed on the coverlay film 128b to correspond to the second LED 127b. Meanwhile, as another example, an opening pattern may be formed in the coverlay film 128b to correspond to the yellow phosphor pattern 210, and the yellow phosphor pattern 210 may be positioned in the opening pattern.

Here, the substrate 128a may be made of, for example, polyimide (PI), but is not limited thereto.

The coverlay film 128b may be formed to have a white color for reflective properties, and when it has reflective properties, light emitted downward from the LED 127 may be reflected to improve light efficiency. Also, the coverlay film 128b is removed from the region where the LED 127 is mounted, and the LED 127 can be mounted on the substrate 128a of the PCB 128 in this region.

As described above, in this embodiment, the yellow phosphor pattern 210 is formed on the upper surface of the PCB 128 in front of the second LED 127b. Accordingly, as in the above second embodiment, yellow white generated by the yellow phosphor pattern 210 is incident on the light entrance portion of the light guide plate 123 in front of the second LED 127b and the vicinity thereof, and the LEDs 127 are arranged in the direction of the arrangement. White color deviation in can be minimized. Therefore, it is possible to improve the Mura phenomenon due to the white color deviation and to implement a narrow bezel.

<The fourth embodiment>

The liquid crystal display device according to the fourth embodiment of the present invention has a configuration similar to that of the liquid crystal display device of the third embodiment. Explain in more detail. Meanwhile, for convenience of description, detailed descriptions of the same or similar components to those of the first embodiment, the second embodiment, or the third embodiment may be omitted below.

13 and 14 are a plan view and a cross-sectional view schematically showing an LED assembly of a liquid crystal display device according to a fourth embodiment of the present invention, respectively.

13 and 14, in the liquid crystal display according to the present embodiment, instead of the yellow fluorescent pattern 210 in the third embodiment, a second LED ( 127b) A surface of the lower substrate 128a may be exposed through the opening pattern 220 by forming an opening pattern 220 corresponding to the front side.

At this time, the base material 128a of the PCB 128 is preferably made of polyimide having a fluorescence characteristic similar to that of the yellow phosphor.

Accordingly, the portion of the substrate 128a made of polyimide exposed through the opening pattern 220 functions similarly to the yellow phosphor.

Accordingly, as in the foregoing second and third embodiments, yellow white is incident to the light entrance portion of the light guide plate 123 in front of the second LED 127b and the portion of the base material 129a exposed through the opening pattern 220 in the vicinity thereof. Thus, the white color deviation in the arrangement direction of the LEDs 127 can be minimized. Therefore, it is possible to improve the Mura phenomenon due to the white color deviation and to implement a narrow bezel.

As described above, in the present invention, a warm white LED that emits yellowish white, that is, the first LED, and a cool white LED that emits blueish white that is higher than this, that is, a second LED that emits a mixture of LEDs are used. 2LEDs are operated in off state in reader mode. Accordingly, it is possible to maximize the reduction in total LED power consumption during normal mode driving and reader mode driving.

Furthermore, a yellow phosphor pattern positioned corresponding to the second LED under the light receiving portion of the light guide plate is formed on the reflector or PCB on which the LED is mounted, or an opening exposing the polyimide base material of the PCB having similar optical properties in place of the yellow phosphor pattern. A pattern can be formed on the coverlay film of the PCB. Accordingly, the white color deviation in the light entrance portion of the light guide plate in front of the second LED can be minimized, thereby improving the Mura phenomenon and implementing a narrow bezel.

The above-described embodiment of the present invention is an example of the present invention, and free modification is possible within the scope included in the spirit of the present invention. Accordingly, this invention covers the modifications and variations of this invention within the scope of the appended claims and their equivalents.

100: liquid crystal display device 110: liquid crystal panel
112: first substrate 114: second substrate
120: backlight unit 121: optical sheet
123: light guide plate 125: reflector
126: LED assembly
127, 127a, 127b: LED, first LED, second LED
128: PCB 128a: substrate
128b: cover film 130: guide panel
140: top case 150: bottom cover
210: yellow phosphor pattern 220: aperture pattern

Claims (12)

a liquid crystal panel;
a light guide plate under the liquid crystal panel;
first and second LEDs disposed along the light incident surface of the light guide plate and emitting yellowish white and bluish white light, respectively;
A yellow phosphor pattern positioned under the light entrance portion of the light guide plate to correspond to the second LED.
A liquid crystal display device comprising a.
According to claim 1,
Further comprising a reflector under the light guide plate,
The yellow phosphor pattern is provided on the reflector
liquid crystal display.
According to claim 1,
Further comprising a PCB mounted on a side where the first and second LEDs are located on one side of the light emitting surface,
The yellow phosphor pattern is provided on the PCB portion located below the light guide plate
liquid crystal display.
According to claim 3,
The PCB includes a substrate and a coverlay film covering an upper surface of the substrate,
The yellow phosphor pattern is provided on the coverlay film or provided in the opening pattern of the coverlay film
liquid crystal display.
According to claim 4,
The coverlay film is a liquid crystal display device having a white color.
a liquid crystal panel;
a light guide plate under the liquid crystal panel;
first and second LEDs disposed along the light incident surface of the light guide plate and emitting yellowish white and bluish white light, respectively;
The first and second LEDs include a PCB mounted on a side located on one side of the light emitting surface,
The PCB includes a substrate made of polyimide and a coverlay film covering an upper surface of the substrate,
An opening pattern positioned corresponding to the second LED is provided in the cover layer under the light entrance part of the light guide plate.
liquid crystal display.
According to claim 6,
The coverlay film is a liquid crystal display device having a white color.
first and second LEDs respectively emitting yellowish white and blueish white light;
The first and second LEDs include a PCB mounted on a side located on one side of the light emitting surface,
The PCB portion located in front of the second LED is provided with a yellow phosphor pattern or an opening pattern exposing the substrate made of polyimide of the PCB to the outside.
LED assembly.
According to claim 8,
The PCB includes a coverlay film covering an upper surface of the substrate,
The yellow phosphor pattern is located on the coverlay film or located in the opening pattern of the coverlay film
LED assembly.
According to claim 8,
The PCB includes a coverlay film covering an upper surface of the substrate,
An opening pattern exposing the substrate to the outside is provided in the coverlay film
LED assembly.
According to claim 9 or 10,
The coverlay film has a white color
LED assembly. According to claim 1,
The yellow phosphor pattern overlaps the light guide plate.

Images