KR102409640B1 - Backlight unit and display device having the same - Google Patents

Abstract

The present invention relates to a backlight unit and a display device including the same, and more particularly, to a backlight unit and display having a structure capable of preventing or reducing an effect on display performance as a light source is directly recognized on a display unit of a display panel It's about the device. According to embodiments of the present invention, it is possible to provide a backlight unit and a display device having a structure in which a light source is prevented from being directly recognized by a display unit of a display panel to minimize an influence on display performance.

Description

A backlight unit and a display device including the same

Embodiments of the present invention relate to a backlight unit and a display device including the same.

As the information society develops, the demand for a display device for displaying an image is increasing in various forms, and in recent years, various display devices such as a liquid crystal display device, a plasma display device, and an organic light emitting display device are utilized.

Among them, the liquid crystal display displays an image by controlling the electric field applied to the liquid crystal layer of the display panel to transmit light emitted from the backlight unit to the display panel while changing the arrangement of the liquid crystal.

Such a backlight unit is a direct type in which a light source is arranged under the display panel and the light from the light source is directly irradiated to the display panel, and an edge type in which a light guide plate is installed under the display panel and light is irradiated from a light source installed at the edge of the light guide plate There is a method, and the direct type method is frequently used due to the advantages of high light utilization efficiency, simple configuration, and easy enlargement.

In order to improve contrast characteristics, such a liquid crystal display device uses a local dimming method in which a backlight is divided into a plurality of blocks and a dimming value is adjusted for each block.

In order to make the liquid crystal display slim, it is necessary to reduce the thickness of the backlight unit. In this case, when the distance between the light source and the diffusion plate is reduced, the air gap between the light source and the diffusion plate is reduced, so that the light emitted from the light source is not sufficiently spread. , there is a limit to spreading the image of the light source using the diffuser plate.

Due to this, there is a problem that hot-spot mura occurs, in which the image of the light source is visually identified due to the high luminance of the portion where the light source is located, which is higher than in a specific block with higher luminance using the local dimming method. becomes evident.

Accordingly, there has been a limit to the slimming of the backlight unit.

Against this background, an object of the embodiments of the present invention is to provide a slim backlight unit and a display device capable of reducing the overall thickness.

Another object of the embodiments of the present invention is to provide a backlight unit and a display device having a structure capable of preventing or reducing an effect on display performance when a light source is directly recognized on a display unit of a display panel.

Another object of the embodiments of the present invention is to provide a slim backlight unit and a display device capable of improving display performance by individually driving a light source to improve contrast characteristics.

In addition, the object of the embodiments of the present invention is not limited thereto, and other objects not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, embodiments of the present invention provide a backlight unit and a display device in which a base plate having a pattern is positioned between two diffusion plates to prevent direct recognition of a light source.

In addition, a backlight unit and a display device in which a light source is individually driven are provided.

According to embodiments of the present invention, it is possible to provide a slim backlight unit and a display device.

In addition, according to embodiments of the present invention, it is possible to provide a backlight unit and a display device having a structure in which a light source is prevented from being directly recognized by a display unit of a display panel to minimize an effect on display performance.

According to the embodiments of the present invention, it is possible to provide a backlight unit and a display device in which display performance is improved by individually driving a light source to improve contrast characteristics.

1 is a diagram illustrating an internal configuration of a display device according to embodiments of the present invention.
2 is a diagram illustrating a cross-section of a display device according to embodiments of the present invention.
3 is a diagram illustrating an implementation example of some components of a display device according to embodiments of the present invention.
4 is a diagram exemplarily illustrating some components of a display device according to embodiments of the present invention.
5 is a diagram illustrating an operating principle of some components of a display device according to embodiments of the present invention.
6 is a diagram illustrating another operating principle of some components of a display device according to embodiments of the present invention.
7 is a diagram illustrating another operating principle of some components of a display device according to embodiments of the present invention.
8 is a diagram illustrating another operating principle of some components of a display device according to embodiments of the present invention.
9 is a view for explaining some components of a display device according to embodiments of the present invention.
10 is a diagram illustrating a driving principle of a display device according to embodiments of the present invention.
11 is a diagram conceptually illustrating effects due to embodiments of the present invention.

Hereinafter, some embodiments of the embodiments of the present invention will be described in detail with reference to exemplary drawings. In adding reference numerals to components of each drawing, the same components may have the same reference numerals as much as possible even though they are indicated in different drawings. In addition, in describing the embodiments of the present invention, when it is determined that a detailed description of a related known configuration or function may obscure the gist of the embodiments of the present invention, the detailed description may be omitted.

In addition, in describing the components of the embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the elements from other elements, and the essence, order, order, or number of the elements are not limited by the terms. When it is described that a component is “connected”, “coupled” or “connected” to another component, the component may be directly connected or connected to the other component, but other components may be interposed between each component. It should be understood that each component may be “interposed” or “connected”, “coupled” or “connected” through another component.

1 is a view showing an internal configuration of a display device according to embodiments of the present invention, FIG. 2 is a diagram showing a cross-section of a display device according to embodiments of the present invention, and FIG. 3 is an embodiment of the present invention It is a view showing an example of implementation of some components of a display device according to the present invention, FIG. 4 is a view showing some components of a display device according to embodiments of the present invention by way of example, and FIG. 5 is embodiments of the present invention FIG. 6 is a diagram illustrating an operation principle of some components of a display device according to an embodiment of the present invention, FIG. 6 is a diagram illustrating another operating principle of some components of a display device according to embodiments of the present invention 8 is a view showing another operating principle of some components of a display device according to the above-described embodiments, FIG. 8 is a diagram showing another operating principle of some components of a display device according to embodiments of the present invention, and FIG. It is a view for explaining some components of a display device according to embodiments, FIG. 10 is a diagram for showing a driving principle of a display device according to embodiments of the present invention, and FIG. 11 is a view for explaining the embodiments of the present invention It is a diagram conceptually showing the effect caused by

1 is a diagram illustrating an internal configuration of a display device according to embodiments of the present invention.

Referring to FIG. 1 , the display device 100 includes a display panel 110 , a backlight unit irradiating light to the display panel 110 , and a chassis structure.

The display panel 110 includes a liquid crystal display device (LCD), a plasma display panel device (PDP), a field emission display device (FED), and an electroluminescence display. device: ELD) and organic light emitting diodes (OLED).

However, below, for convenience of explanation, the light irradiated from the backlight unit to the display panel 110 is transmitted by controlling the electric field applied to the liquid crystal layer of the display panel 110 to display an image by changing the arrangement of the liquid crystal. A liquid crystal display device will be described as an example.

Meanwhile, the display device 100 mainly protects the case top 180 , which is a chassis structure that covers and protects the front edge and the outside of the side of the display panel 110 , and the backlight unit under the display panel 110 . It may include a cover bottom 170 made of a metal material.

Looking at this structure with reference to FIG. 2 , the case top 180 that covers the front edge and the outside of the side of the display panel 110 is coupled to the case top 180 and supports the lower surface of the display panel 110 . A guide panel 160 and a cover bottom 170 coupled to the guide panel 160 are included as a chassis structure, and a backlight unit structure is included between the display panel 110 and the cover bottom 170 .

Looking at the structure of the backlight unit, the optical sheet 150 is positioned under the display panel 110 .

The optical sheet 150 is provided by stacking a single or a plurality of optical plates or optical films, and a plurality of stacked optical sheets 150 include a diffusion film, a prism film, and a double brightness enhancement film (DBEF), etc. may be included.

Meanwhile, the light source 120 of the backlight unit irradiating light to the display panel 110 may be a plurality of light emitting diodes (LEDs).

The light source 120 may be disposed in any one of an edge-type and a direct-type method according to a display form of the display device 100 .

In the side-type liquid crystal display device, a reflective sheet (not shown) and a light guide plate (not shown) are provided inside the display device 100, the light source 120 is disposed on the side of the light guide plate, and an optical sheet ( 150 is positioned, and the display panel 110 is positioned on the optical sheet 150 .

However, the light source 120 arranged in a direct manner is illustrated in FIG. 1 , and hereinafter, for convenience, the light source 120 arranged in a direct manner will be described as an example. However, the present invention is not limited thereto, and the light source 120 may be disposed in a lateral manner.

The light source 120 disposed in a direct manner may be disposed on the upper surface of the cover bottom 170 , and the substrate 220 and the reflector 210 may be disposed under the light source 120 .

Meanwhile, two or more diffusion plates 140 positioned on the light source 120 and one or more base plates 131 interposed between the two or more diffusion plates 140 may be included in the upper portion of the above-described light source 120 .

The diffuser plate 140 is positioned on the light source 120 , and being positioned on the light source 120 means that the diffuser plate 140 is positioned on the path of the light irradiated from the light source 120 comprehensively. It can be used in a broad sense.

The diffusion plate 140 may be made of a transparent material or a material having a haze characteristic including particles or patterns. That is, the diffusion plate 140 is a component for supplying a surface light source as a whole by refracting and diffusing the light irradiated from the light source 120, and may include a light diffusing agent or a pattern, etc., and when haze characteristics are given, It is possible to uniformly spread the light irradiated from the light source 120 and supply it to the display panel 110 .

Two or more diffuser plates 140 may be provided, and in this case, one diffuser plate 140 and the other diffuser plate 140 among the two or more diffuser plates 140 may have the same optical characteristics, It could be something else.

For example, both of the two or more diffusion plates 140 may be made of a transparent material, or only one of the two or more diffusion plates 140 may have a haze characteristic, and both of the two or more diffusion plates 140 may be provided with a haze characteristic. A haze characteristic is given to the , but the degree of the haze characteristic may be different from each other.

Meanwhile, one or more base plates 131 may be interposed between two or more diffusion plates 140 .

The base plate 131 may be in the form of a plate or a film, and may be made of a transparent material or a material having a haze characteristic including particles or patterns.

When the base plate 131 has a haze characteristic including a light diffusing agent or pattern, it is possible to uniformly spread the light irradiated from the light source 120 together with the diffuser plate 140 and supply it to the display panel 110 . do.

In addition, one or more base plates 131 may be provided.

When the base plate 131 is positioned between two or more diffuser plates 140 , the light irradiated from the light source 120 is first diffused from the diffuser plate 140 located close to the light source 120 and then the base Since it is incident on the plate 131 , the reflective effect of the light irradiated by the base plate 131 may be improved.

A plurality of patterns 133 having optical characteristics different from those of the base plate 131 may be disposed on the base plate 131 at positions corresponding to positions of the plurality of light sources 120 .

Referring to FIG. 3 , the base plate 131 includes a pattern 133 . This pattern 133 may also be implemented in the base plate 131 of FIG. 2, but is omitted for convenience.

The shape of the pattern 133 may be implemented in various ways.

That is, as shown in FIG. 3 , it may be a convex lens shape forming a spherical shape on the base plate 131 , a rectangular shape, or a concave lens shape or polygonal shape. It can have a shape to transform the properties as desired.

Meanwhile, referring to FIGS. 3 and 4 , the pattern 133 is positioned on the base plate 131 .

However, the pattern 133 may be located inside the base plate 131 or may be located under the base plate 131 .

The pattern 133 can be formed on the base plate 131 through various methods such as application, printing, coating, and adhesion.

The pattern 133 may have a reflectance greater than that of the base plate 131 . More specifically, when the irradiation light of the light source 120 is incident on the pattern 133 having a higher reflectivity than the base plate 131 , more light is reflected in the region where the pattern 133 is located, so the amount of transmitted light this becomes less

Therefore, when the pattern 133 is positioned to correspond to the region where the light source 120 is located, the amount of light transmitted directly from the light source 120 to the display panel 110 can be reduced in the region where the pattern 133 is located. It is possible to improve the phenomenon that the light source 120 is recognized by the display unit of the display device 100 .

The pattern 133 may be formed of a material including a plurality of beads 410 as shown in FIG. 4A .

When the pattern 133 includes the bead 410 , a part of the light incident on the pattern 133 is transmitted and a part is reflected, and the reflected light may be mainly diffusely reflected.

Referring to FIG. 5 , the light irradiated from the light source 120 to the base plate 131 is partially reflected at the interface between the base plate 131 and the pattern 133 , and the pattern ( Due to the plurality of beads 410 included in 133 ), the irradiation light is diffusely reflected in the direction of the light source 120 while colliding with the beads 410 .

Meanwhile, the plurality of beads 410 included in the pattern 133 may have various materials, shapes, sizes, and refractive indices as needed. That is, in order for the light irradiated from the light source 120 to be easily diffusely reflected, it may be implemented in various forms depending on the wavelength characteristics of the light irradiated from the light source 120 .

As an example of the beads 410, when the plurality of beads 410 have an average particle diameter of 10 to 1000 nm and a refractive index of 1.2 to 2.5, the diffuse reflectance of the visible light wavelength band can be maximized. As described above, the diffuse reflection characteristic can be maximized by adjusting the size and refractive index of the bead 410 according to the characteristics of the light irradiated from the light source 120 .

Also, the bead 410 may be included in the pattern 133 in an amount of 10 to 50 wt% based on the weight of the pattern 133 . When the bead 410 is 10 parts by weight or more based on the weight of the pattern 133 , the diffusion rate of light irradiated from the light source 120 can be improved, and the bead 410 is 50 parts by weight or less relative to the weight of the pattern 133 . An excessive decrease in transmittance of light irradiated from the back light source 120 may be prevented.

The bead 410 may be made of PMMA (Poly (methyl methacrylate)), PS (Polystyrene), Si, PBMA (Poly (n-butyl methacrylate)), TiO, Nylon, etc. In addition, light can be diffused or refracted. It can be composed of various types of plastic or ceramic materials.

The reflected light is reflected again from the reflector 210 under the light source 120 and is incident on the base plate 131 area except for the area where the pattern 133 is located, so that it may be incident in the direction of the display panel 110 . .

Accordingly, the light source 120 is placed in the display area of the display device 100 by reflecting the light directly irradiated from the light source 120 to the pattern 133 while maximizing the use of the irradiated light from the light source 120 to reduce the amount of light. Direct recognition can be prevented.

Meanwhile, the pattern 133 may include an optical filter 420 as shown in FIG. 4B .

When the pattern 133 includes the optical filter 420 , a part of the light incident to the pattern 133 is transmitted and a part is reflected, and the reflected light may be mainly specularly reflected.

Looking at this with reference to FIG. 6 , the light irradiated from the light source 120 to the base plate 131 is partially reflected at the interface between the base plate 131 and the pattern 133 , and the pattern ( 133) is mirror-reflected in the direction of the light source 120 due to the optical filter 420 included.

The optical filter 420 included in the pattern 133 may have various materials, refractive indexes, and thicknesses as needed.

As an example of such an optical filter 420, a multi-layer filter in which a plurality of optical films or optical plates having a thickness and refractive index having a specular reflection characteristic for a specific wavelength or a plurality of optical plates are laminated is applied to continuously emit the irradiated light from the light source 120 It may be to reduce the amount of light irradiated by the light source 120 that has passed through the pattern 133 in the entire wavelength region while mirror-reflecting the pattern 133 .

In other words, in the white light irradiated from the light source 120 , the optical film or optical plate having the thickness d and the refractive index n at which blue light having a wavelength range of about 420 to 490 μm is reflected is the first of the optical filter 420 . The light source 120 that is located in the layer, and has passed through the optical filter 420, such that an optical film or optical plate having a thickness and refractive index that reflects red light and green light is located in the second and third layers, respectively. The amount of irradiated light may be decreased in the entire wavelength region. Alternatively, such an optical film or optical plate may be implemented in more than three layers.

The reflected light is reflected again from the reflector 210 under the light source 120 and is incident on the base plate 131 area except for the area where the pattern 133 is located, so that it may be incident in the direction of the display panel 110 . .

Accordingly, since light directly irradiated from the light source 120 to the pattern 133 is mirror-reflected to minimize the amount of light, the light source 120 can be prevented from being directly recognized in the display area of the display device 100 .

Meanwhile, the optical filter 420 included in the pattern 133 may absorb a specific wavelength region of light incident on the pattern 133 and transmit the remaining wavelength region.

Referring to FIG. 7 , the light irradiated to the optical filter 420 having a characteristic of absorbing light in the specific wavelength region may be absorbed in the specific wavelength region while passing through the optical filter 420 .

As a result, the transmission characteristics of the optical filter 420 are derived in a form in which only light transmittance in a specific wavelength region is reduced as shown in FIG. 7 .

Therefore, when the optical filter 420 having a characteristic of absorbing a specific wavelength region corresponding to the wavelength of the light irradiated from the light source 120 is applied, the light directly irradiated from the light source 120 to the pattern 133 is absorbed and the amount of light By lowering the light source 120 as much as possible, it is possible to prevent the light source 120 from being directly recognized in the display area of the display device 100 .

Meanwhile, a plurality of phosphors 430 may be included in the pattern 133 as shown in FIG. 4C .

Referring to FIG. 8 , the light irradiated from the light source 120 to the base plate 131 is reflected or scattered by the phosphor 430 included in the pattern 133 , and a color corresponding to the wavelength of the incident light. In (C1), it is converted into a color (C2) corresponding to the converted wavelength while being reflected or scattered.

The phosphor 430 included in the pattern 133 refers to particles formed to absorb light of a predetermined wavelength and to emit light having the same wavelength as or different from the absorbed light. The size of the phosphor 430 may be, for example, an average particle diameter of about 15 nm to 100 nm, and the size of the particles may be different depending on light having a wavelength to be emitted. The shape of the phosphor 430 is not particularly limited, and may include a spherical shape, an ellipsoid, a polygonal shape, or an amorphous shape.

The phosphor 430 is, for example, a particle (green phosphor) capable of absorbing light of any one wavelength within the range of 420 nm to 490 nm and emitting light of any one wavelength within the range of 490 nm to 580 nm or 420 nm to 490 nm. It may be a particle (red phosphor) capable of absorbing light of any one wavelength within the range and emitting light of any one wavelength within the range of 580 nm to 780 nm.

In addition, the phosphor 430 includes particles capable of emitting light of any one wavelength within the range of 490 nm to 580 nm (green phosphor) and particles capable of emitting light of any one wavelength within the range of 580 nm to 780 nm (red). Phosphor) may be a composite phosphor to which a compound is applied.

At this time, the green phosphor is (Sr,Ba,Mg) ₂ SiO ₄ :Eu, Al ₅ Lu ₃ O ₁₂ :Ce, Y ₃ Al ₅ O ₁₂ :Ce, La ₃ Si ₆ N ₁₁ :Ce, (Sr,Ba, Eu) ₂ SiO ₄ :Eu, β-SiAlON: Si _6-z Al _z O _z N _8-z :EU, Lu ₃ Al ₅ O ₁₂ :Ce, (Lu,Gd) ₃ Al ₅ O ₁₂ :Ce It may include one or more, or any one or more of materials having a composition such as other types of garnets, silicates, sulfides, and oxynitrides.

In addition, the red phosphor is (Sr,Ba,Mg) ₃ SiO ₅ :Eu, (Sr,Ca)AlSiN ₃ :Eu, CaAlSiN ₃ :Eu, MSi _1-z Al _z O _z N _2-z :Eu, α-Sialon : Ca _x Eu _y (Si,Al) ₁₂ (O,N) ₁₆ , CaAlSiN, (Sr,Ca)AlSiN ₃ :Eu, K ₂ Si _1-x F ₆ :Mn _x containing any one or more, In addition, it may include any one or more of materials having a composition such as other types of garnets, silicates, sulfides, oxynitrides, and nitrides.

In the above case, the blue (C1)-based irradiation light of the light source 120 provided by the blue LED emitting blue light is reflected or scattered due to the pattern 133 to which the red and green phosphors 430 are applied, while being red and green. It can be converted to a white (C2) series containing this.

Alternatively, when the light source 120 itself is implemented in the form of an LED package including a fluorescent material, or the light source 120 is implemented as a red or green LED emitting light of a color other than blue, the pattern 133 can be implemented in various forms of converting an arbitrary color (C1) emitted from the light source 120 into white (C2).

The above pattern 133 may also be implemented in various modified examples. For example, a plurality of beads 410 are included in the pattern 133 and a phosphor 430 is included together, so that part of the light emitted from the light source 120 is diffusely reflected and transmitted due to the plurality of beads 410 . The light is reflected or scattered by the phosphor 430 , and the color is converted to be irradiated to the display panel 110 .

Alternatively, the optical filter 420 is included in the pattern 133 and the phosphor 430 is included together, so that a part of the irradiated light from the light source 120 is mirror-reflected due to the optical filter 420, and the transmitted light is the phosphor ( The color may be converted while being reflected or scattered by the 430 , and may be irradiated to the display panel 110 .

In addition to this, a plurality of beads 410 and an optical filter 420 may be applied to the pattern 133 together, or a phosphor 430 may be further applied to the pattern 133 .

As described above, when the pattern 133 converts the optical characteristics of the irradiated light into various forms and irradiates the display panel 110 , the light source 120 is prevented from being directly recognized in the display area of the display device 100 . ) is possible to convert the color of the irradiated light, so additional components such as a fluorescent film may be omitted from the backlight unit.

Meanwhile, while the pattern 133 is positioned at a position corresponding to the position of the light source 120 , the size W2 of the pattern 133 may be provided to have a size corresponding to the size W1 of the light source 120 .

That is, as shown in FIG. 5 , the size W2 of the pattern 133 is the same as or larger than the size W1 of the light source 120 .

Alternatively, the size W2 of the pattern 133 may be determined based on the distance h between the light source 120 and the base plate 131 .

That is, when the distance h between the light source 120 and the base plate 131 is relatively wide and the air gap between the light source 120 and the diffusion plate 140 is greater than 10 mm, the light source 120 Since the irradiated light can be sufficiently spread, the size W2 of the pattern 133 may be the same as the size W1 of the light source 120 .

In addition, when the distance h between the light source 120 and the base plate 131 is small, the air gap between the light source 120 and the diffusion plate 140 is small, so that the irradiated light of the light source 120 cannot be sufficiently spread. , the size W2 of the pattern 133 is greater than the size W1 of the light source 120 . In addition, when the distance h between the light source 120 and the base plate 131 becomes narrower, the size W2 of the pattern 133 may be made larger.

Meanwhile, a binder 910 may be included in all or part of at least one of the upper and lower surfaces of the base plate 131 to be adhered to the two or more diffusion plates 140 .

The binder 910 may be a thermosetting resin or a photocurable resin, and the refractive index of the binder 910 may be the same as that of the base plate 131 .

More specifically, referring to FIG. 9 , an embodiment in which the binder 910 is included in all or part of an upper surface or a lower surface of the base plate 131 can be confirmed.

FIG. 9A shows the base plate 131 including the binder 910 in a partial area of the upper surface of the pattern 133 including the binder 910 .

That is, the binder 910 and the above-described plurality of beads 410, optical filter 420 or phosphor 430 are mixed together in the pattern 133 and coated on the base plate 131, and then the base plate 131 is applied. It may be adhered to the upper diffusion plate 140 .

Alternatively, as shown in FIG. 9B , after the binder 910 is applied to the area between the two patterns 133 on the upper surface of the base plate 131 , the base plate 131 may be adhered to the upper diffusion plate 140 .

Also, as shown in FIG. 9C , after the binder 910 is applied to all or a part of the lower surface of the base plate 131 , it may be adhered to the diffusion plate 140 under the base plate 131 .

Through this, the lower portion of the base plate 131 is adhered to and supported by the lower diffusion plate 140 , and the upper portion of the base plate 131 is adhered to and fixed to the upper diffusion plate 140 , while being fixed between the two diffusion plates 140 . It may have a structure in which the base plate 131 is fixed and laminated.

The above-described implementation examples of FIGS. 9A to 9C may be implemented with various modifications such as any two implementation examples or all implementation examples being applied.

Meanwhile, referring to FIG. 10 , the display device 100 includes a light source driving circuit 1010 for driving a light source 120 , and the light source driving circuit 1010 may individually drive a plurality of light sources 120 . .

The light source driving circuit 1010 controls a driving voltage and a driving current according to the current flowing through each of the plurality of light source 120 blocks.

In addition, the light source driving circuit 1010 generates a control signal having a duty ratio between 0 and 100% according to a plurality of dimming signals from a timing controller (not shown), and the light source 120 using the generated control signal. Blocks can be driven individually.

The plurality of light sources 120 may be composed of a light source 120 block (not shown) in which the light sources 120 are bundled. Such blocks of the light source 120 may be driven for each block by the control signal generated by the light source driving circuit 1010 .

Here, the control signal is a signal for adjusting the on/off times of the plurality of light sources 120 constituting the light source 120 block. The control signal may be a PWM signal, and the duty ratio of the control signal. ), the light emission time of the plurality of light sources 120 and the amount of current flowing to the plurality of light sources 120 may be adjusted.

For example, the light emission time of the plurality of light sources 120 driven by the control signal having a large duty ratio may be long, and the light emission time of the plurality of light sources 120 driven by the control signal having the large duty ratio may be short.

The duty ratio of the control signal may be determined by the dimming signal received from the timing controller.

The effects of the above-described display device 100 will be conceptually reviewed with reference to FIG. 11 .

As shown in FIG. 11 , when the base plate 131 to which the pattern 133 is applied is not positioned between the light source 120 and the display panel 110 , the light source 120 is displayed on the display panel 110 as shown in FIG. 11A . ), a hot-spot mura that is directly recognized in the display area occurs.

To improve this, when the base plate 131 to which the pattern 133 is applied is applied to the backlight unit, particularly, when it is applied between two or more diffusion plates 140 , the display panel 110 as shown in FIG. 11B . Since it is possible to prevent the light source 120 from being recognized in the display, it is possible to improve display performance, and it is also possible to implement a slim backlight unit and display device 100 .

As described above, according to the embodiments of the present invention, it is possible to provide a slim backlight unit and a display device.

In addition, according to embodiments of the present invention, it is possible to provide a backlight unit and a display device having a structure in which a light source is prevented from being directly recognized by a display unit of a display panel to minimize an effect on display performance.

According to the embodiments of the present invention, it is possible to provide a backlight unit and a display device in which display performance is improved by individually driving a light source to improve contrast characteristics.

In the above, even though all the components constituting the embodiment of the present invention are described as being combined or operated in combination, the present invention is not necessarily limited to this embodiment. That is, within the scope of the object of the present invention, all the components may operate by selectively combining one or more.

In addition, terms such as "comprises", "comprises" or "have" described above mean that the corresponding component may be embedded, unless otherwise specified, excluding other components. Rather, it should be construed as being able to further include other components. All terms, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs, unless otherwise defined. Terms commonly used, such as those defined in the dictionary, should be interpreted as being consistent with the meaning of the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present invention.

The above description is merely illustrative of the technical spirit of the present invention, and various modifications and variations will be possible without departing from the essential characteristics of the present invention by those skilled in the art to which the present invention pertains. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

100: display device 110: display panel
120: light source 131: base plate
133: pattern 140: diffuser plate
160: guide panel 170: cover bottom
180: case top 410: bead
420: optical filter 430: phosphor
910: binder 1010: light source driving circuit

Claims (19)

multiple light sources;
two or more diffusion plates positioned on the light source; and
At least one base plate interposed between the two or more diffuser plates,
In the base plate,
A backlight unit in which a plurality of patterns having optical characteristics different from those of the base plate are disposed at positions corresponding to positions of the light source. According to claim 1,
The reflectance of the pattern is greater than the reflectance of the base plate backlight unit. According to claim 2, wherein the pattern,
A backlight unit including a plurality of beads that diffusely reflect the light incident on the pattern. According to claim 2, wherein the pattern,
A backlight unit including an optical filter for mirror-reflecting light incident to the pattern. According to claim 2, wherein the pattern,
and an optical filter absorbing light of a specific wavelength region of the light incident to the pattern. According to claim 2, wherein the pattern,
A backlight unit including a plurality of phosphors for converting colors of light incident to the pattern. The backlight unit of claim 1 , wherein the base plate has a haze characteristic. According to claim 1, wherein the pattern,
A backlight unit having a size corresponding to the size of the light source. According to claim 1, wherein the size of the pattern,
A backlight unit determined based on a distance between the light source and the base plate. According to claim 1,
A backlight unit including a binder in all or a part of at least one of an upper surface and a lower surface of the base plate. 11. The method of claim 10,
The binder is a backlight unit included in the pattern. display panel; and
a backlight unit irradiating light to the display panel;
The backlight unit is
multiple light sources;
two or more diffusion plates positioned on the light source; and
At least one base plate interposed between the two or more diffuser plates,
In the base plate,
A display device in which a plurality of patterns having optical characteristics different from those of the base plate are disposed at positions corresponding to positions of the light source. 13. The method of claim 12,
The reflectance of the pattern is greater than that of the base plate. The method of claim 13, wherein the pattern,
A display device including a plurality of beads that diffusely reflect the light incident to the pattern. The method of claim 13, wherein the pattern,
and an optical filter for mirror-reflecting light incident to the pattern. The method of claim 13, wherein the pattern,
and an optical filter absorbing light in a specific wavelength region of the light incident to the pattern. The method of claim 13, wherein the pattern,
A display device comprising a plurality of phosphors for converting colors of light incident to the pattern. According to claim 12, wherein the pattern,
A display device having a size corresponding to the size of the light source. 13. The method of claim 12,
Further comprising a light source driving circuit for driving the light source,
The light sources are individually driven display devices.

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