KR20120045968A - Liquid crystal display device - Google Patents

Abstract

PURPOSE: A liquid crystal display device is provided to increase brightness and a color reproduction rate. CONSTITUTION: A second substrate(102) includes a second electrode and a transparent layer(123c). A blue light blocking filter(200) is formed on an external surface of the second substrate wherein the blue light blocking filter corresponds to an area where a red light emitting material and a green light emitting material are formed. A refractive index of the liquid crystal layer is lower or higher than a refractive index of a first substrate(101) whether an electric field is applied to a liquid crystal layer(130). Therefore, blue light is transmitted or blocked.

Description

[0001] Liquid crystal display device [0002]

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device in which a polarizing plate is eliminated.

In line with the recent information age, the display field has also been rapidly developed, and a liquid crystal display device (FPD) is a flat panel display device (FPD) having advantages of thinning, light weight, and low power consumption. LCD, plasma display panel device (PDP), electroluminescence display device (ELD), field emission display device (FED), etc. : It is rapidly replacing CRT.

Among them, liquid crystal display devices are most actively used in the field of notebooks, monitors, TVs, etc. because of their excellent contrast ratio and high contrast ratio.

A configuration of the liquid crystal display will be described in more detail with reference to FIG. 1, which is a cross-sectional view of a general liquid crystal display.

As shown in the figure, a liquid crystal panel 10 having an array substrate 2 and a color filter substrate 4 facing each other with a liquid crystal layer 3 interposed therebetween is disposed on the liquid crystal panel 10 and a lower portion thereof. It has a configuration of the backlight 40 is disposed, the pixel region (P) is defined on one surface of the first substrate 2, called the dual array substrate, each thin film transistor (T) is provided One-to-one correspondence with the transparent pixel electrode 28 provided in each pixel area P is carried out.

The thin film transistor Tr includes a gate electrode 11, a gate insulating film 13, a semiconductor layer 15, and source and drain electrodes 17 and 19.

A protective layer 16 is formed on the front surface of the array substrate 2 including the thin film transistor Tr, and the pixel electrode 28 is electrically connected to the drain electrode 19 of the thin film transistor Tr. .

In addition, one surface of the second substrate 4 called the color filter substrate, which faces the liquid crystal layer 50 therebetween, covers the non-display elements such as the thin film transistor T of the first substrate 2 while the pixel electrode ( A lattice-like black matrix 32 covering the pixel region P is formed to expose 28.

In addition, as an example, the R, red, G, and B color filters 34 and the transparent common electrode covering all of them are sequentially arranged to correspond to each pixel area P in the lattice. 36) is configured.

At this time, the outer surfaces of the first and second substrates 2 and 4 are attached with polarizing plates 20 and 30 for selectively transmitting only specific polarized light.

In addition, a seal pattern 70 is formed along the edges of both substrates 2 and 4 to prevent leakage of the liquid crystal layer 50 filled therebetween.

Since the liquid crystal display device does not have its own light emitting element, a separate light source is required. To this end, a backlight 40 is provided on the back of the liquid crystal panel 10 to supply light.

The backlight 40 has a structure in which one or a pair of lamps 42 are disposed at one side of the light guide plate 41, and a plurality of optical sheets (not shown) are mounted on the light guide plate 41.

On the other hand, the liquid crystal display device has recently been widely used, such as a desktop computer monitor and a wall-mounted television, as well as a portable computer. It is actively underway.

However, despite efforts to fabricate a liquid crystal display device in a light weight and thin form, there are too many components constituting the liquid crystal display device, which hinders the light weight and thinness of the liquid crystal display device.

The present invention has been made to solve the above problems, and a first object of the present invention is to provide a lightweight and thin liquid crystal display device.

In addition, it is a second object to simplify the structure of the liquid crystal display device.

Another object of the present invention is to provide a liquid crystal display device having improved luminance and color reproducibility.

In order to achieve the above object, the present invention provides a light source for emitting blue light; A first substrate on which the light source is located along one side edge, the light emitted from the light source is incident therein, and a first electrode is formed; A second substrate facing the first substrate and having a second electrode, a transparent layer for transmitting the red (R) light emitting material, the green (G) light emitting material, and the blue light as it is for each pixel region; A liquid crystal layer interposed between the first and second substrates; And a blue light blocking filter formed on an outer surface of the second substrate corresponding to the pixel region where the red light emitting material and the green light emitting material are formed, and the refractive index of the liquid crystal layer depends on whether an electric field is applied to the liquid crystal layer. Provided is a liquid crystal display device which is smaller or larger than a refractive index to transmit and block the blue light.

In this case, the blue light blocking filter absorbs light in the wavelength range of 400 ~ 500nm, the blue light blocking filter is made of a mixture of any one material of BiO2, ZnO, Ce2O3 and CaCO3, ZrO2, TiO, Ar2O3 or It consists of a yellow filter.

When the refractive index of the liquid crystal layer is greater than the refractive index of the first substrate, the polarization component incident in parallel with the liquid crystal molecules of the liquid crystal layer among the blue light incident on the first substrate is transmitted to the liquid crystal layer, and the liquid crystal layer When the refractive index of the layer is smaller than the refractive index of the first substrate, blue light incident on the first substrate is totally reflected in the first substrate.

In addition, an incident angle of the blue light emitted from the light source is greater than a critical angle incident to the first substrate, and the first substrate is a plastic material or poly such as polymethylmethacrylate (PMMA), which is an acrylic transparent resin. Manufactured from carbonate (PC) series, glass series, and COP (cyclo-olefin polymer) series.

In this case, a thin film transistor is formed for each pixel region on the first substrate, and a light absorbing plate is provided on the rear surface of the first substrate.

In addition, a reflecting mirror is provided on the other edge opposite to one edge of the first substrate on which the light source is located.

As described above, according to the present invention, a feature of the present invention allows the first substrate to replace the role of a conventional light guide plate, a pixel electrode on the first substrate, and a common electrode on the second substrate, By interposing the liquid crystal layer between the substrate and the second substrate, it is possible to significantly reduce the weight and volume compared to the existing liquid crystal display device, it is possible to provide a lightweight and thin liquid crystal display device.

In addition, by using a difference in refractive index between the first substrate and the liquid crystal layer, only specific polarized light can be selectively transmitted and blocked, thereby eliminating an existing polarizing plate. Therefore, a lighter and thinner liquid crystal display device can be realized, and the process cost can be reduced and the process time can be shortened by simplifying the structure of the liquid crystal display device.

In particular, the liquid crystal display of the present invention further includes a blue light blocking filter, thereby improving luminance and color reproducibility.

1 is a cross-sectional view of a general liquid crystal display device.
2 is a cross-sectional view schematically illustrating a plurality of pixel areas of a liquid crystal display according to an exemplary embodiment of the present invention.
3A to 3B are schematic views showing driving characteristics of a liquid crystal display according to an exemplary embodiment of the present invention.
4a to 4b is a result of measuring the color reproduction with or without the blue light blocking filter.

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

2 is a cross-sectional view schematically illustrating a plurality of pixel areas of a liquid crystal display according to an exemplary embodiment of the present invention.

As shown in the drawing, the liquid crystal display device of the present invention is formed by bonding the first and second substrates 101 and 102 to each other with the liquid crystal layer 130 interposed therebetween, and leakage of the liquid crystal layer 130 filled therebetween. A seal pattern 170 is formed along the edges of both substrates 101 and 102 to prevent damage.

In this case, a plurality of thin film transistors T are formed on the first substrate 101 which is the lower substrate, and the color filter layer 123 is formed on the second substrate 102 which is the upper substrate, and the first and second substrates 101 are formed. , The liquid crystal layer 130 interposed between the layers 102 is a twisted nematic (TN) mode, and in the off state of the voltage, the long axis (ne) direction of the molecules is kept parallel to both substrates 101 and 102. The alignment state twisted at the azimuth angle of 90 degrees from the 1st board | substrate 101 to the 2nd board | substrate 102 is shown.

Looking at each of these in more detail, the first substrate 101 is a plastic material or polycarbonate, such as polymethylmethacrylate (PMMA), an acrylic transparent resin, which is one of transparent materials capable of transmitting light. (polycarbonate: PC) series, glass series, COP (cyclo-olefin polymer) series.

In this case, for convenience of description, an area in which the thin film transistor T is formed is defined as a switching area TrA, and an area in which an image is realized is defined as a display area AA.

The gate P (not shown) and the data wire (not shown) intersect on the first substrate 101 to define the pixel P. The pixel electrode is formed on the inner surface of the display area AA of each pixel P. 112 is formed.

In addition, a thin film transistor T is provided in the switching region TrA, which is an intersection point between the gate line (not shown) and the data line (not shown). The thin film transistor T includes the gate electrode 111 and the gate insulating layer 113. ), The semiconductor layer 115, and the source and drain electrodes 117 and 119.

A protective layer 116 is formed on the front surface of the first substrate 101 including the thin film transistor T, and the pixel electrode 112 is electrically connected to the drain electrode 119 of the thin film transistor T. do.

In this case, the semiconductor layer 115 is composed of an active layer 115a of pure amorphous silicon and an ohmic contact layer 115b of amorphous silicon including an impurity. In this case, the thin film transistor T is amorphous of pure and impurity in the drawing. A bottom gate type consisting of the silicon silicon 115a and 115b is shown as an example, and may be formed as a top gate type including a polysilicon semiconductor layer as a modification thereof.

The inner surface of the second substrate 102 facing the first substrate 101 is located in a region corresponding to the thin film transistor T, the gate wiring (not shown), and the data wiring (not shown), and the pixel electrode ( A lattice-like black matrix 121 is formed to surround the pixel region P to expose the 112.

The color filter layer 123 is formed in the grid of the black matrix 121 to correspond to each pixel area RP, GP, or BP, and covers the black matrix 121 and the color filter layer 123 and the liquid crystal layer 130. The common electrode 125 is disposed to face the pixel electrode 112 with a gap between the two electrodes.

The LED assembly 140 is positioned along one side edge of the first substrate 101, and the LED assembly 140 has a plurality of LEDs 141 and a plurality of LEDs 141 spaced apart from each other by a predetermined interval. PCB 143 mounted by surface mount technology (SMT).

The plurality of LEDs 141 are connected in parallel through a power wiring (not shown) formed on the PCB 143, respectively, and are supplied with power. In this case, the plurality of LEDs 141 emit blue light, respectively, in this case, the second The color filter layer 123 formed on the substrate 102 includes red (R) and green (G) light emitting materials 123a, 123b and transparent layers 123c including phosphors for each pixel region RP, GP, and BP. Is done.

That is, the red pixel area RP in which the existing red color filter (not shown) is formed is made of a red light emitting material 123a including a red phosphor that converts blue light emitted from the LED 141 into red (R). The green pixel area GP in which the existing green color filter (not shown) is formed is made of a green light emitting material 123b including a green phosphor that converts blue light emitted from the LED 141 into green (G). will be.

In addition, the blue pixel area B-P in which the existing blue color filter is formed is formed of a transparent layer 123c that transmits the blue light emitted from the LED 141 as it is.

At this time, as the red phosphor, one of Y2O2S, La2O2S, (Ca, Sr, Ba) 2Si5N8, Cazen (CaAlSiN3), (La, Eu) 2W3O12, (Ca, Sr, Ba) 3MgSi2O8, Li (Eu, Sm) W2O8 The green phosphor is made of one of (Ca, Sr, Ba) 2 SiO 4, BAM, alpha sialon (α-SiAlON), Ca 3 Sc 2 Si 3 O 12, Tb 3 Al 5 O 12, and LiTbW 2 O 8.

Accordingly, the liquid crystal display of the present invention emits R, G, and B colors for each pixel region R-P, G-P, and B-P, thereby realizing full color through mixing of light.

In particular, the liquid crystal display of the present invention corresponds to the outer surface of the second substrate 102 and corresponds to the red pixel area RP on which the red light emitting material 123a is formed and the green pixel area GP on which the green light emitting material 123b is formed. As a result, the blue light blocking filter 200 is further positioned.

Through this, brightness and color reproduction rate are improved. We will discuss this in more detail later.

At this time, the blue light emitted from the plurality of LEDs 141 is incident to the inside of the first substrate 101, and the inside of the first substrate 101 is advanced by several total reflections inside the first substrate 101.

That is, in the liquid crystal display of the present invention, the first substrate 101 replaces the role of the light guide plate (41 in FIG. 1) of the conventional backlight unit (40 in FIG. 1).

As a result, the weight and volume of the liquid crystal display device can be significantly reduced, thereby providing a lightweight and thin liquid crystal display device.

In particular, the liquid crystal display of the present invention can delete the existing polarizing plates (20, 30 of Figure 1).

In more detail, in the liquid crystal display of the present invention, the S polarization component of the blue light may be selectively transmitted and the P polarization component may be totally reflected by the refractive index difference at the boundary between the first substrate 101 and the liquid crystal layer 130. have.

Here, the principle that the polarization is separated at the boundary between the first substrate 101 and the liquid crystal layer 130 is as follows.

The liquid crystal layer 130 extends from the first substrate 101 to the second substrate 102 with the long axis ne of the liquid crystal molecules in parallel with both substrates 101 and 102 in a voltage off state. It shows twisted alignment at 90 ° azimuth angle.

Accordingly, the liquid crystal layer 130 has a refractive index in the long axis direction of the liquid crystal molecules, and if the refractive index of the first substrate 101 is defined as ni, ne> ni when no electric field is applied to the liquid crystal layer 130. To satisfy the relationship.

When an electric field is applied to the liquid crystal layer 130, the liquid crystal molecules are arranged perpendicular to the substrates 101 and 102, so that the liquid crystal layer 130 exhibits a refractive index in the short axis (no) direction of the liquid crystal molecules, where no < The relationship of ni is satisfied.

That is, the refractive index of the liquid crystal layer 130 may vary depending on whether the liquid crystal layer 130 is applied to an electric field.

Therefore, the refractive index of the liquid crystal layer 130 satisfies the above relationship with the refractive index of the first substrate 101.

Accordingly, when no electric field is applied to the liquid crystal layer 130, when blue light incident on the first substrate 101 from the plurality of LEDs 141 reaches a boundary between the first substrate 101 and the liquid crystal layer 130, The S polarized light component and the P polarized light component of the blue light feel either component of ne or no of the liquid crystal layer 130.

In particular, the S polarization component, which is a component incident in parallel with the liquid crystal molecules among the S polarization component and the P polarization component, feels ne of the liquid crystal layer 130 to which an electric field is not applied.

As a result, ne of the liquid crystal layer 130 expressing a larger refractive index than the refractive index of the first substrate 101 causes the S-polarized component to pass through the boundary between the first substrate 101 and the liquid crystal layer 130.

That is, only the S-polarized component parallel to the liquid crystal molecules of the liquid crystal layer 130 passes through the liquid crystal layer 130, thus displaying white.

On the contrary, the P-polarized component which is incident perpendicularly to the liquid crystal molecules is blocked at the boundary between the first substrate 101 and the liquid crystal layer 130. In this case, the P-polarized component feels no of the liquid crystal layer 130. 101 is totally reflected at the boundary between the liquid crystal layer 130 and the liquid crystal layer 130.

In this case, the totally reflected P-polarized component continues to proceed inside the first substrate 101, where the total reflection is transmitted to the second medium through some of the light at the boundary where the two mediums are in contact with the other part of the boundary. It is common to reflect light from the light source. Especially, when light is transmitted from dense medium to small medium, the light does not progress at the boundary between two media when the incident angle is more than the critical angle represented by θc. It is a phenomenon that all is reflected.

The critical angle is determined by the refractive indices of the two media, which can be defined by Equation 1 below according to Snell's law.

........식(1)

Expression (1)

Therefore, when the angle of incidence of the light is greater than or equal to the critical angle, the light does not penetrate from the first substrate 101 of ni, which is a dense medium, to the liquid crystal layer 130 of no, which is a small medium, and is totally reflected in the first substrate 101. will be.

When an electric field is applied to the liquid crystal layer 130, the blue light incident on the first substrate 101 from the plurality of LEDs 141 reaches the boundary between the first substrate 101 and the liquid crystal layer 130. As for the S polarization component and the P polarization component, either component of n _e or n _o of the liquid crystal layer 130 is felt.

In this case, since the liquid crystal molecules of the liquid crystal layer 130 are arranged perpendicular to the substrates 101 and 102, the P polarization component is incident in parallel with the liquid crystal molecules of the liquid crystal layer 130, so that the liquid crystal layer 130 feels no. , The S-polarized component feels ne of the liquid crystal layer 130.

Therefore, although the P-polarized component incident in parallel with the liquid crystal molecules of the liquid crystal layer 130 must pass through the liquid crystal layer 130, no, which is a refractive index of the liquid crystal layer 130 to which an electric field is applied, is determined by the first substrate 101. Since it is smaller than the refractive index, the P polarization component does not pass through the boundary between the first substrate 101 and the liquid crystal layer 130, and totally reflects within the first substrate 101.

In addition, since the S polarization component feels ne of the liquid crystal layer 130 larger than the refractive index of the first substrate 101, the S polarization component may pass through the boundary between the first substrate 101 and the liquid crystal layer 130, but the liquid crystal molecules It is blocked by being perpendicular to the arrangement direction of.

That is, when an electric field is applied to the liquid crystal layer 130, both the S polarization component and the P polarization component of the blue light do not pass through the boundary between the first substrate 101 and the liquid crystal layer 130.

Therefore, the blue light does not proceed to the liquid crystal layer 130 to display black.

At this time, both the S-polarized component and the P-polarized component which did not proceed to the liquid crystal layer 130 are totally reflected in the first substrate 101.

Meanwhile, the present invention is based on the premise that blue light emitted from the plurality of LEDs 141 has an angle of incidence within a predetermined range and is incident on the first substrate 101. We will discuss this in more detail later.

At this time, it is preferable to form the absorbing plate 150 on the back of the first substrate 101, the absorbing plate 150 is emitted to the back of the first substrate 101 without being totally reflected in the first substrate 101. The light absorbed is prevented from leaking to the rear surface of the first substrate 101.

In particular, the absorption plate 150 serves to block and absorb external light incident from the outside.

In more detail, in the display device, in addition to the light emitted from the LED 141, a specific light is incident from the outside into the display device, and the external light thus reflected is reflected by the first substrate 101 to contrast the display device. This greatly reduces the contrast.

Therefore, in order to prevent the external light from being reflected by the first substrate 101, the absorption plate 150 is further provided on the rear surface of the first substrate 101, thereby absorbing the external light to block the reflection itself. .

In addition, a reflector (not shown) may be provided at the other side edge of the first substrate 101 opposite to one edge where the LED assembly 140 is positioned, and the first substrate 101 may be provided through the reflector (not shown). The total reflection of the light within the X) is prevented from escaping to the other edge of the first substrate 101.

In particular, it is reflected by a reflector (not shown), thereby improving the brightness of light.

On the other hand, a gate insulating film 113, a protective layer 116, and a pixel electrode 112 are formed on the first substrate 101 of the display area AA where an image is substantially formed, thereby forming the first substrate 101. The gate insulating layer 113, the protective layer 116, and the pixel electrode 112 are positioned between the liquid crystal layer 130, but the refractive indexes of the gate insulating layer 113, the protective layer 116, and the pixel electrode 112 are zero. Compared to the refractive indices of the first substrate 101 and the liquid crystal layer 130, it is very insignificant and does not affect the difference in refractive index between the first substrate 101 and the liquid crystal layer 130.

As described above, the liquid crystal display of the present invention allows the first substrate 101 to replace the existing light guide plate 41 of FIG. 1, and the thin film transistor T and the pixel on the first substrate 101. After forming the electrode 112 and forming the color filter layer 123 and the common electrode 125 on the second substrate 102 facing the first substrate 101, the first substrate 101 and the second substrate are formed. By interposing the liquid crystal layer 130 between the substrates 102, the weight and volume can be significantly reduced compared to the existing liquid crystal display device, thereby providing a lightweight and thin liquid crystal display device.

In addition, by using the refractive index difference between the first substrate 101 and the liquid crystal layer 130, the existing polarizing plates 20 and 30 of FIG. 1 may be deleted.

Therefore, a lighter and thinner liquid crystal display device can be realized, and the process cost can be reduced and the process time can be shortened by simplifying the structure of the liquid crystal display device.

In particular, the liquid crystal display of the present invention improves the luminance and color reproduction. This will be described in more detail with reference to FIGS. 3A to 3B below.

3A to 3B are schematic views showing driving characteristics of the liquid crystal display according to the exemplary embodiment of the present invention.

As shown in the drawing, the LED assembly 140 is positioned along one edge of the first substrate 101, and the thin film transistor (T in FIG. 2) and the pixel electrode (FIG. 2) are disposed on the first substrate 101. 112 is formed, the color filter layer 123 and the common electrode (125 in FIG. 2) are formed on the second substrate 102, and the liquid crystal layer (between the first and second substrates 101 and 102). 130).

In this case, the LED 141 of the LED assembly 140 emits blue light, and the color filter layer 123 has a red light emitting material 123a, a green light emitting material 123b, and a transparent layer for each pixel area RP, GP, and BP. 123c.

The blue light blocking filter 200 is formed to correspond to the red pixel area R-P and the green pixel area G-P on the outer surface of the second substrate 102.

The blue light blocking filter 200 may be formed by mixing any one of BiO 2, ZnO, Ce 2 O 3, and any one of CaCO 3, ZrO 2, TiO, Ar 2 O 3, or a yellow filter.

Since the blue light blocking filter 200 absorbs light in the wavelength band of 400 to 500 nm, only the blue light having the wavelength band is blocked. In this case, the transmittance of the blue light blocking filter 200 is 5% or less at a wavelength of 450 nm, 80% or more at 535 nm, and 90% or more at 650 nm.

That is, the blue light blocking filter 200 mixes colors in a process in which blue light emitted from the LED 141 passes through the red and green light emitting materials 123a and 123b to realize the colors of red (R) and green (G). It serves to prevent this from happening.

That is, although blue light passes through the red and green light emitting materials 123a and 123b to realize the colors of red (R) and green (G), the blue light is mixed with the color.

Accordingly, in the process of emitting the red (R) and green (G) colors to the outside of the second substrate 102, the red and green pixels through the blue light blocking filter 200 to prevent the blue light from being mixed with the colors thereof. The blue light is prevented from being emitted to the outside of the second substrate 102 in the regions RP and GP.

Here, when the green pixel area GP is taken as an example, as shown in FIG. 3A, the thin film transistor T (in FIG. 2) of the green pixel area GP is selectively controlled to be a pixel electrode (112 in FIG. 2). When a signal voltage is applied, an electric field having a specific intensity is formed between the pixel electrode 112 of FIG. 2 and the common electrode 125 of FIG. 2, and the liquid crystal layer of the green pixel region GP is formed by the electric field having the specific intensity. The liquid crystal molecules 130 are arranged perpendicular to the substrates 101 and 102 so that the refractive index of the liquid crystal molecules in the short axis direction is expressed.

Accordingly, when blue light emitted from the plurality of LEDs 141 enters the first substrate 101 and reaches the boundary between the first substrate 101 and the liquid crystal layer 130, the S-polarized component and the P-polarized component of the blue light are Both do not pass through the boundary between the first substrate 101 and the liquid crystal layer 130, and totally reflect inside the first substrate 101.

Therefore, the green pixel area G-P displays black.

As shown in 3b, when no voltage is applied to the pixel electrode 112 of FIG. 2 to maintain the off state, the blue light emitted from the plurality of LEDs 141 is applied to the first substrate 101. When the light is incident into the first substrate 101 and reaches the boundary between the first substrate 101 and the liquid crystal layer 130, the S-polarized component and the P-polarized component of the blue light proceed to the liquid crystal layer 130.

At this time, only the S polarization component of blue light parallel to the liquid crystal molecules of the liquid crystal layer 130 passes through the mode liquid crystal layer 130, and the P polarization component is totally reflected in the first substrate 101.

Therefore, the S-polarized component passed through the liquid crystal layer 130 passes through the green light emitting material 123b.

At this time, the S polarization component of the blue light to implement the color of the green (G) in the process of passing through the green light emitting material (123b), the color of the green (G) to be implemented is implemented by mixing the blue light color.

However, since the blue light blocking filter 200 is formed on the outer surface of the second substrate 102 corresponding to the green pixel area GP of the liquid crystal display device of the present invention, the color of the green color G is substantially mixed. The blue light is blocked by the blue light blocking filter 200 so that only the vivid green (G) color is implemented in the image of the green pixel area GP.

Similarly, in implementing the red (R) color of the red pixel area RP, blue light is mixed in the red (R) color passing through the red light emitting material 123a, but the red color of the red pixel area RP is substantially the same. Only the vivid red (R) color is implemented in the image.

Here, the luminance of the liquid crystal display according to the exemplary embodiment of the present invention when the blue light blocking filter 200 is provided is 147.5 nit, but when the blue light blocking filter 200 is not provided, the luminance is 130.8 nit and the blue light blocking is performed. Compared with the case where the filter 200 is not provided, the luminance when the blue light blocking filter 200 is provided is improved by about 42%.

As described above, the blue light blocking filter 200 is further provided on the outer surface of the second substrate 102 corresponding to the red and green pixel areas R-P and G-P, thereby improving luminance and color reproducibility.

The color reproducibility can be confirmed with reference to FIGS. 4A to 4B, which is illustrated below. FIG. 4A is a color coordinate system of the liquid crystal display according to an exemplary embodiment of the present invention, in which a blue light blocking filter 200 is provided. 200 is a color coordinate system of the liquid crystal display device which is not provided.

Referring to FIG. 4A, it can be seen that the liquid crystal display of the present invention having the blue light blocking filter 200 satisfies 99.4% of the standards of the National Television System Committee (NTSC) in color reproduction rate. Referring to FIG. 4B, when the blue light blocking filter 200 is not provided, the color reproduction rate is 91.9%, and the color reproduction rate when the blue light blocking filter is provided is improved.

Meanwhile, the present invention is based on the premise that the blue light emitted from the plurality of LEDs 141 has an incidence angle within a predetermined range and is incident on the first substrate 101. The incidence angle of the blue light emitted from the plurality of LEDs 141 is It must be greater than the critical angle.

Therefore, the incident angle of the blue light emitted from the plurality of LEDs 141 must satisfy the condition of θwg = 90 ° -θiso, so that total reflection occurs at the boundary between the first substrate 101 and the liquid crystal layer 130.

At this time, the incident angle of the blue light emitted from the LED 141 and incident into the first substrate 101 is preferably 33.6 ° (± 6.8 to ± 23.6).

As described above, the liquid crystal display of the present invention allows the first substrate 101 to replace the role of the conventional light guide plate (41 in FIG. 1), and the thin film transistor (T in FIG. 2) on the first substrate 101. ) And a pixel electrode (112 in FIG. 2), a color filter layer 123 and a common electrode (125 in FIG. 2) are formed on the second substrate 102 facing the first substrate 101. By interposing the liquid crystal layer 130 between the first substrate 101 and the second substrate 102, it is possible to significantly reduce the weight and volume compared to the existing liquid crystal display device, to provide a lightweight and thin liquid crystal display device Can be.

In addition, by using the difference in refractive index between the first substrate 101 and the liquid crystal layer 130, only specific polarized light can be selectively transmitted and blocked, so that the existing polarizing plates 20 and 30 of FIG. 1 can be deleted. Therefore, a lighter and thinner liquid crystal display device can be realized, and the process cost can be reduced and the process time can be shortened by simplifying the structure of the liquid crystal display device.

In particular, the liquid crystal display of the present invention further includes a blue light blocking filter 200, thereby improving luminance and color reproducibility.

Meanwhile, in the above description, the TN mode liquid crystal layer 130 is taken as an example. However, the liquid crystal layer 130 may include in-plane switching (IPS), vertical alignment (VA), and electrically controllable birefrengence (ECB) applied to the liquid crystal display. OCB (Optically Compensated Birefringence) mode is also applicable.

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.

101: first substrate, 102: second substrate, 111: gate electrode, 112: pixel electrode
113: gate insulating film, 114: common electrode, 115: semiconductor layer, 116: protective layer
117: source electrode, 119: drain electrode
123: color filter layer (123a: red color filter, 123b: green color filter, 123c: transparent layer)
130: liquid crystal layer, 140: LED assembly (141: LED, 143: PCB)
150: absorber plate, 170: seal pattern, 200: blue light blocking filter
T: thin film transistor, TrA: switching area, AA: display area
RP, GP, BP: Red, Green, Blue Pixel Area

Claims (10)

A light source emitting blue light;
A first substrate on which the light source is located along one side edge, the light emitted from the light source is incident therein, and a first electrode is formed;
A second substrate facing the first substrate and having a second electrode, a transparent layer for transmitting the red (R) light emitting material, the green (G) light emitting material, and the blue light as it is for each pixel region;
A liquid crystal layer interposed between the first and second substrates;
A blue light blocking filter formed on an outer surface of the second substrate corresponding to the pixel region in which the red light emitting material and the green light emitting material are formed.
And a refractive index of the liquid crystal layer is smaller or larger than the refractive index of the first substrate, depending on whether an electric field is applied to the liquid crystal layer to transmit and block the blue light.
The method of claim 1,
The blue light blocking filter absorbs light in the wavelength range of 400 to 500 nm.
The method of claim 2,
The blue light blocking filter may be formed by mixing any one of BiO 2, ZnO, Ce 2 O 3, and any one of CaCO 3, ZrO 2, TiO, Ar 2 O 3, or a yellow filter.
The method of claim 1,
When the refractive index of the liquid crystal layer is greater than the refractive index of the first substrate, the polarization component incident in parallel with the liquid crystal molecules of the liquid crystal layer of the blue light incident on the first substrate is transmitted to the liquid crystal layer.
The method of claim 1,
And a blue light incident on the first substrate is totally reflected in the first substrate when the refractive index of the liquid crystal layer is smaller than the refractive index of the first substrate.
The method of claim 1,
And an incident angle of the blue light emitted from the light source is greater than a critical angle incident to the first substrate.
The method of claim 1,
The first substrate may be a plastic material such as polymethyl methacrylate (PMMA), an acrylic transparent resin, or polycarbonate (PC), glass, or cyclo-olefin polymer (COP). Liquid crystal display device manufactured.
The method of claim 1,
And a thin film transistor formed on each of the pixel regions on the first substrate.
The method of claim 1,
And a light absorbing plate disposed on a rear surface of the first substrate.
The method of claim 1,
And a reflecting mirror at the other edge of the first substrate on which the light source is located.

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