KR20100112679A - Image display device capable of controlling viewing angle - Google Patents

Abstract

PURPOSE: An image display device capable of controlling viewing angle after controlling optical diffusion angle area is provided to control the viewing angle through a simple structure by forming a plurality of slots on the bottom of the optical diffusion plate. CONSTITUTION: A first backlight unit(110) selectively radiates light. A second backlight unit(120) is arranged on the first backlight unit. The second backlight unit selectively radiates the light. The first backlight unit and the second backlight unit are arranged in order to penetrate the light. A light path restriction plate(130) forms a plurality of slots restricting the route of the light.

Description

IMAGE DISPLAY DEVICE CAPABLE OF CONTROLLING VIEWING ANGLE}

The present invention relates to a video display device capable of adjusting the viewing angle.

In general, various electronic display devices such as TVs, computer monitors, and screens embedded in portable information devices such as mobile phones are designed to have a wide viewing angle in order to be able to read them in as many viewing positions as possible.

However, there may be situations where it is useful to have a display that is visible only in a narrow range of angles. For example, if you are reading confidential or private documents on the display of a mobile device where there is a person around you, it may be necessary to minimize the risk that others around you will see the documents on the display.

The necessity of adjusting the viewing angle has emerged, and various methods for adjusting the viewing angle have been introduced.

For example, a sheet polarizer can be used to surround the screen surface, to use a switchable diffuser, to add a liquid crystal panel or polarizer with a patterned liquid crystal alignment, or to use a hologram. It became.

However, these conventional methods have various problems, such as a complicated structure, which greatly increases manufacturing costs or makes it difficult to adjust a sufficient viewing angle.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an image display device capable of adjusting the viewing angle as needed through a simple structure.

According to an exemplary embodiment of the present invention, an image display apparatus includes a first backlight unit, a second backlight unit, an optical path limiting plate, and an image display panel. The first backlight unit is formed to selectively emit light, and the second backlight unit is disposed on the first backlight unit and is formed to selectively emit light. The light path limiting plate is disposed between the first backlight unit and the second backlight unit to allow light emitted from the first backlight unit to pass therethrough, and the light path restrictor is configured to reduce the diffusion of the light emitted and emitted from the first backlight unit. A plurality of slots is formed to limit the path. The image display panel is disposed on the second backlight unit to display an image so that light emitted from the first backlight unit and the second backlight unit can pass therethrough.

The image display device according to another embodiment of the present invention includes a first backlight unit, a light path limiting plate, a second backlight unit, and an image display panel. The first backlight unit is formed to selectively emit light, and includes a first light guide plate, a first lamp disposed to irradiate light to the first light guide plate, and a first diffuser plate disposed on the first light guide plate. It includes. The light path limiting plate is disposed between the first diffuser plate and the first light guide plate, and a plurality of slots are formed to restrict a path of light emitted from the first light guide plate and introduced into the first diffuser plate. The second backlight unit is disposed on the first backlight unit and is formed to selectively emit light. The image display panel is disposed on the second backlight unit to display an image so that light emitted from the first backlight unit and the second backlight unit can pass therethrough.

An image display apparatus according to another embodiment of the present invention includes a first backlight unit, a second backlight unit, and an image display panel. The first backlight unit is formed to selectively emit light, and the second backlight unit is disposed on the first backlight unit and is formed to selectively emit light. The image display panel is disposed on the second backlight unit to display an image so that light emitted from the first backlight unit and the second backlight unit can pass therethrough. In this case, the second backlight unit includes a light guide plate, a lamp disposed to irradiate light to the light guide plate, and a diffuser plate disposed on the light guide plate, and the bottom surface of the light guide plate is diverged from the first backlight and flows in. A plurality of slots are formed to limit the path of the incoming light so that the diffusion of the light is reduced.

An image display apparatus according to another embodiment of the present invention includes a first backlight unit, a second backlight unit, and an image display panel. The first backlight unit is formed to selectively emit light, and the second backlight unit is disposed on the first backlight unit and is formed to selectively emit light. The image display panel is disposed on the second backlight unit to display an image so that light emitted from the first backlight unit and the second backlight unit can pass therethrough. In this case, the first backlight unit includes a light guide plate, a lamp disposed to irradiate light to the light guide plate, and a diffuser plate disposed on the light guide plate, and the bottom surface of the diffuser plate is diverged from the light guide plate. A plurality of slots are formed to limit the path of the incoming light so that the spread of the light is reduced.

In order to implement a relatively narrow viewing angle, the first backlight unit is operated to be turned on and the second backlight unit is operated to be turned off so that light emitted from the first backlight unit is transmitted to the plurality of slots. After passing therebetween, the light emitting device may proceed toward the image display panel, and operate to turn on the second backlight unit when the second backlight unit is turned on when a relatively wide viewing angle is desired. The apparatus may proceed toward the image display panel without passing between slots.

The plurality of slots may be formed extending in a direction perpendicular to the direction to narrow the viewing angle.

The plurality of slots may be formed in a grid pattern.

According to the present invention, two backlight units are arranged up and down, and the light path limiting plate having a plurality of slots for limiting the light diffusion path is provided to adjust the light diffusion deployment angle region passing through the image display panel. I can regulate it. Therefore, a video display device capable of adjusting the viewing angle through a simple structure can be realized.

In addition, instead of having a separate light path limiting plate, by forming a plurality of slots on the bottom surface of the light guide plate of the backlight unit disposed above or by forming a plurality of slots on the bottom surface of the diffuser plate of the backlight unit disposed below, The viewing angle can be adjusted through a simple structure.

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

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like parts are designated by like reference numerals throughout the specification. When a part, such as a layer or plate, is said to be "above" or "below" another part, this includes not only the other part "just above" or "just below" but also another part in the middle. . On the contrary, when a part is “just above” or “just below” another part, there is no other part in the middle.

The image display device according to the exemplary embodiment of the present invention includes back light units 110 and 120 that may operate separately. Hereinafter, the backlight unit indicated by reference numeral 110 will be referred to as a first backlight unit, and the backlight unit indicated by reference numeral 120 will be referred to as a second backlight unit.

The first and second backlight units 110 and 120 may be implemented in a similar manner to a backlight unit used as a light source such as a liquid crystal display (LCD), and the description of the same or similar parts will be described. Omit.

As shown in the figure, the first and second backlight units 110 and 120 are arranged side by side in the vertical direction. In detail, the second backlight unit 120 is disposed on the first backlight unit 110. In this case, the vertical direction refers to a direction away from a direction close to the image display panel 140 implementing the image.

The first and second backlight units 110 and 120 are formed to selectively emit light. That is, the first and second backlights 110 and 120 may operate to emit light when in an on state, and may be in a state where no light is emitted when in an off state. The first and second backlights 110 and 120 may be powered on or off to be in an on or off state, and although not shown in the drawings, circuit elements for supplying and controlling such power may be provided.

For example, the first backlight unit 110 may include a light guide plate 111, a lamp 113, and a diffuser plate 115. Similarly, the second backlight unit 120 may also include a light guide plate ( 121, a lamp 123, and a diffusion plate 125 may be provided.

The light guide plates 111 and 121, the lamps 113 and 123, and the diffuser plates 115 and 125 may be formed similarly to the light guide plates, lamps, and diffusion plates of the backlight unit of the conventional liquid crystal display, and have similar functions. To perform. Briefly, the lamps 113 and 123 are light sources that emit light and may be implemented as lamps that emit white light, such as a cold cathode fluorescence lamp (CCFL), and the light guide plates 111 and 121 may be lamps. It functions to more uniformly transmit the light emitted by the (113, 123) over the entire surface and may be formed of a light and high light transmittance material such as acrylic resin, the diffusion plate (115, 125) is a light guide plate (111, The light emitted through 121 may be diffused to have a more uniform luminance to flow into the image display panel 140. In this case, although the lamps 113 and 123 are illustrated as being disposed on one side of the light guide plates 111 and 121, the number and positions of the lamps 113 and 123 are not limited thereto. In addition, the lamps 113 and 123 may be surrounded by lamp covers 117 and 127 that reflect light, so that the light emitted from the lamps 113 and 123 may effectively enter the light guide plates 111 and 121.

The first and second backlight units 110 and 120 may include a frame serving as a case for making the light guide plates 111 and 121, the lamps 113 and 123, and the diffuser plates 115 and 125 into one unit. have.

The reflector 150 is disposed under the light guide plate 111 of the first backlight unit 110 positioned below. The reflective plate 150 reflects light toward the image display panel 140.

Meanwhile, the first and second backlight units 110 and 120 may further include a member such as a prism sheet, a protective sheet, and the like, which will be apparent to those skilled in the art. Description thereof will be omitted.

In the following description, the light guide plate indicated by reference numeral 111 is referred to as a first light guide plate, the light guide plate indicated by reference numeral 121 is referred to as a second light guide plate, and the lamp indicated by reference numeral 113 is referred to as a first lamp. And the lamp indicated by reference numeral 123 is called a second lamp, the diffuser plate indicated by reference numeral 115 is called a first diffuser plate, and the diffuser plate indicated by reference numeral 125 is called a second diffuser plate. do.

The light path limiting plate 130 is disposed below the second backlight unit 120. More specifically, the light path limiting plate 130 is disposed between the first backlight unit 110 and the second backlight unit 120. The structure and function of the optical path limiting plate 130 will be described in detail later.

The image display panel 140 is disposed on the second backlight unit 120 to allow light emitted from the first backlight unit 110 and the second backlight unit 120 to pass therethrough.

The image display panel 140 may be implemented as any image display panel capable of displaying a desired image by light passing therethrough. For example, it may be implemented as a backlight projection display panel such as a liquid crystal display panel.

Meanwhile, a frame 141 for fixing the image display panel 140, the first backlight unit 110, the light path limiting plate 130, and the second backlight unit 110 to one unit may be provided. have. 1 schematically shows the structure of the frame 141, and the shape and structure of the frame 141 are not limited to those shown in the drawings.

1 and 2, an optical path diffuser 130 is disposed between the first backlight unit 110 and the second backlight unit 120. That is, the optical path diffuser plate 130 is disposed above the first backlight unit 110 and below the second backlight unit 120. Accordingly, the light from the first backlight unit 110 passes through the light path limiting plate 130 and then enters the image display panel 140, and the light from the second backlight unit 120 passes through the light path limiting plate ( It flows into the image display panel 140 without passing through 130.

The light path limiting plate 130 serves to limit the diffusion of light by limiting the path of the light. Accordingly, when the second backlight unit 120 is turned on (in this case, the first backlight unit may be turned on or turned off), the light emitted from the second backlight unit 120 undergoes a diffusion process to obtain an image. When the display panel 140 passes through the display panel 140 to obtain a relatively wide viewing angle, the first backlight unit 110 is turned on and the second backlight unit 120 is turned off. As the light emitted from the first backlight unit 110 passes through the light path limiting plate 130, the diffusion is limited, and as a result, the development range of the light passing through the image display panel 140 is reduced to obtain a relatively narrow viewing angle. will be. The structure and operation of the optical path limiting plate 130 for implementing the viewing angle adjustment function will be described in detail below.

The light path limiting plate 130 may be formed to have a flat plate shape, may be formed of any material having good light transmittance, and may be formed of, for example, an acrylic material.

2 and 3, the light path limiting plate 130 is provided with a plurality of slots 131 for limiting the light propagation path. At this time, the interval and depth between the slots 131 may be appropriately changed according to the required viewing angle adjustment degree. In the drawing, although the slot 131 is formed on the bottom surface of the optical path limiting plate 130 by way of example, the slot may be formed on the upper surface of the optical path limiting plate 130.

4 and 5 are views for explaining the principle that the viewing angle is changed by the action of the slot 131 of the optical path limiting plate 130. 4 is a diagram illustrating a process of implementing a relatively wide viewing angle, and FIG. 5 is a diagram illustrating a process of implementing a relatively narrow viewing angle.

First, referring to FIG. 4, when a relatively wide viewing angle is to be realized, the second backlight unit 120 operates to be turned on. In this case, the first backlight unit 110 may be in an on state or in an off state.

When the second lamp 123 is turned on and emits light, the emitted light flows into the second light guide plate 121, and the light is uniformized by the second light guide plate 121 to move toward the second diffuser plate 125. . After the light is diffused by the second diffusion plate 125, the light passes through the image display panel 140. At this time, a viewing angle corresponding to the angle region through which the light passes is obtained.

Meanwhile, referring to FIG. 5, when a relatively narrow viewing angle is to be realized, the first backlight unit 110 operates to be turned on and the second backlight unit 120 is turned off. Therefore, the light emitted from the first backlight unit 110 passes through the light path limiting plate 130 and then proceeds toward the image display panel 140.

When the first lamp 113 is turned on to emit light, the emitted light flows into the first LGP 111, and the light is uniformized by the first LGP 111 and then passes through the first diffuser plate 115. Spreads. Then, the light passes through the light path limiting plate 130 and then passes through the second light guide plate 121 and the second diffusion plate 125 and then passes through the image display panel 140.

When light passes through the optical path restrictor 130, it passes through the space between neighboring slots 131. That is, the light introduced into the slot 131 is limited to advancing, so that the slot 131 blocks the optical path. Accordingly, as the light passes through the light path limiting plate 130 where the slot 131 is formed, the light spreading angle region is reduced, and consequently, light diffusion is limited.

As the light emitted from the first backlight unit 110 passes through the light path limiting plate 130 and is emitted while the light deployment angle region is reduced, the deployment angle region of the light passing through the image display panel 140 is reduced. This results in a relatively reduced viewing angle. That is, when operating as shown in FIG. 5, a relatively narrow viewing angle is obtained compared to FIG. 4, and accordingly, the viewing angle can be adjusted.

On the other hand, the plurality of slots 131 may be formed to extend in a direction perpendicular to the direction to narrow the viewing angle. That is, when the plurality of slots 131 are formed extending in any direction, the diffusion of light in the direction perpendicular to the direction is limited, so that the viewing angle in the direction perpendicular to the direction of the slot is narrowed.

For example, in the drawing, a case in which the plurality of slots 131 extend in the X-axis direction is exemplarily illustrated, but in this case, the viewing angle in the Y-axis direction is narrowed. On the other hand, the slot 131 may be formed to extend in the Y-axis direction, in this case it can be adjusted to narrow the viewing angle in the X-axis direction. Meanwhile, slots extending in the X-axis direction and slots extending in the Y-axis direction may be provided at the same time, so that the slots may be formed in a lattice pattern. Done.

6 to 9 are diagrams for describing an image display device according to another exemplary embodiment.

6 and 7, the light path limiting plate 230 is disposed between the first light guide plate 111 and the first diffuser plate 115 of the first backlight unit 110. Since the remaining elements are the same as in the above-described embodiment, description thereof will be omitted.

A plurality of slots 231 are formed on the bottom surface of the light path limiting plate 230. Since the structure and function of the optical path limiting plate 230 are the same as in the above-described embodiment, description thereof will be omitted.

FIG. 8 is a diagram illustrating a case where a relatively wide viewing angle is implemented, and FIG. 9 is a diagram illustrating a case where a relatively narrow viewing angle is implemented.

Referring to FIG. 8, when the second lamp 123 of the second backlight unit 120 is turned on, a relatively wide viewing angle is realized. At this time, the first lamp 113 of the first backlight unit 110 may be turned on or off.

On the other hand, referring to FIG. 9, in order to obtain a relatively narrow viewing angle, the second backlight unit 120 is turned off and the first backlight unit 110 is turned on. After the light emitted from the first lamp 113 of the first backlight unit 110 passes through the light path limiting plate 230 after passing through the first light guide plate 111, the first diffuser plate 115 and the second light guide plate ( 121 and the second diffusion plate 125, the light is reduced by the action of the slot 231 of the optical path limiting plate 230, the light development angle region is reduced as a result of which the diffusion is limited and accordingly the image display panel The unfolding angle area of the light passing through 140 is reduced. As a result, a relatively narrow viewing angle is obtained as compared with FIG. 8.

10 and 11 are views for explaining still another embodiment of the present invention.

According to the present exemplary embodiment, the second backlight unit 320 may include a light guide plate 321, a lamp 323, and a diffusion plate 325, and focus light emitted from the lamp 323 to the light guide plate 321. The lamp cover 327 may be provided.

10 and 11, a plurality of slots 322 are formed on the bottom surface of the light guide plate 321. Since the shape and function of the slot 323 is the same as the slot of the optical path limiting plate in the above-described embodiment, a description thereof will be omitted.

When the lamp 323 of the second backlight unit 320 is turned on, the light from the lamp 323 passes through the light guide plate 321 and the diffusion plate 325 and then passes through the image display panel 140. The light spreading angle region by diffusion is formed to obtain a predetermined viewing angle.

On the other hand, when the lamp 323 of the second backlight unit 320 is turned off and the first lamp 113 of the first backlight unit 110 is turned on, the light from the first lamp 113 is turned on. After passing through the first light guide plate 111 and the first diffuser plate 115, a space between the plurality of slots 322 formed on the bottom surface of the light guide plate 321 of the second backlight unit 320 passes. In this process, the light diffusion path is limited, and as a result, the spread angle region of the light diffused by the diffusion plate 325 and passing through the image display panel 140 is reduced, thereby obtaining a relatively narrow viewing angle.

12 and 13 are views for explaining still another embodiment of the present invention.

According to the present exemplary embodiment, the first backlight unit 210 may include a light guide plate 211, a lamp 213, and a diffusion plate 215, and focus light emitted from the lamp 213 to the light guide plate 211. The lamp cover 217 may be provided.

11 and 12, a plurality of slots 212 are formed on the bottom surface of the diffusion plate 211. Since the shape and function of the slot 212 is the same as the slot of the optical path limiter in the above-described embodiment, a description thereof will be omitted.

When the lamp 123 of the second backlight unit 120 is turned on, light from the lamp 123 passes through the light guide plate 121 and the diffusion plate 125 and then passes through the image display panel 140. As a result, a light development angle region due to light diffusion is formed to obtain a predetermined viewing angle.

On the other hand, when the lamp 123 of the second backlight unit 120 is turned off and the lamp 213 of the first backlight unit 210 is turned on, the light from the lamp 213 is light guide plate 211. Pass through the diffusion plate 215 and then pass through the second backlight unit 120 and the image display panel 140 in order. At this time, since the plurality of slots 212 are formed on the bottom surface of the diffuser plate 211, the light passes through the space between the plurality of slots 212 of the diffuser plate 211 and in this process the light diffusion path Is limited, and as a result, the diffusion development angle region of the light diffused by the second diffusion plate 125 of the second backlight unit 120 and passing through the image display panel 140 is reduced. As a result, a relatively narrow viewing angle is obtained.

Although the embodiments of the present invention have been described above, the scope of the present invention is not limited thereto, and it is recognized that the present invention is easily changed and equivalent by those skilled in the art to which the present invention pertains. Includes all changes and modifications to the scope of the matter.

1 is a schematic exploded perspective view of a video display device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1.

3 is a perspective view illustrating a bottom surface of a light path limiting plate of an image display device according to an exemplary embodiment of the present invention.

4 and 5 are views for explaining a viewing angle adjustment function of the image display device according to an embodiment of the present invention.

6 is a schematic exploded perspective view of a video display device according to another embodiment of the present invention.

7 is a cross-sectional view taken along the line VII-VII of FIG. 6.

8 and 9 are views for explaining a viewing angle adjustment function of the image display device according to an exemplary embodiment of the present invention.

10 is a schematic exploded perspective view of a video display device according to another embodiment of the present invention.

FIG. 11 is a cross-sectional view taken along the line?-? Of FIG.

12 is a schematic exploded perspective view of a video display device according to another embodiment of the present invention.

FIG. 13 is a cross-sectional view taken along the line XIII-XIII of FIG. 12.

Claims (7)

A first backlight unit configured to selectively emit light, A second backlight unit disposed on the first backlight unit and formed to selectively emit light; A plurality of rays disposed between the first backlight unit and the second backlight unit to allow light emitted from the first backlight unit to pass therethrough, and restricting a path of the incoming light so as to reduce diffusion of the light emitted and emitted from the first backlight unit; Slotted optical path limiter, and And an image display panel disposed on the second backlight unit to display an image to allow light emitted from the first backlight unit and the second backlight unit to pass therethrough. A first backlight including a first light guide plate, a first lamp disposed to irradiate light to the first light guide plate, and a first diffuser plate disposed on the first light guide plate unit, An optical path limiting plate disposed between the first diffuser plate and the first light guide plate and having a plurality of slots configured to restrict a path of light emitted from the first light guide plate and introduced into the first diffuser plate; A second backlight unit disposed on the first backlight unit and formed to selectively emit light; and And an image display panel disposed on the second backlight unit to display an image to allow light emitted from the first backlight unit and the second backlight unit to pass therethrough. A first backlight unit configured to selectively emit light, A second backlight unit disposed on the first backlight unit and formed to selectively emit light; and An image display panel disposed on the second backlight unit to display an image to allow light emitted from the first backlight unit and the second backlight unit to pass therethrough; The second backlight unit may include a light guide plate, a lamp disposed to irradiate light to the light guide plate, and a diffuser plate disposed on the light guide plate, and the bottom surface of the light guide plate may diffuse diffusion of the light emitted from the first backlight. And a plurality of slots for restricting a path of the introduced light so as to be reduced. A first backlight unit configured to selectively emit light, A second backlight unit disposed on the first backlight unit and formed to selectively emit light; and An image display panel disposed on the second backlight unit to display an image to allow light emitted from the first backlight unit and the second backlight unit to pass therethrough; The first backlight unit may include a light guide plate, a lamp disposed to irradiate light to the light guide plate, and a diffuser plate disposed on the light guide plate, and the diffusion of light emitted and emitted from the light guide plate may be provided on the bottom surface of the diffuser plate. And a plurality of slots for restricting a path of the introduced light so as to be reduced. The method according to any one of claims 1 to 4, In order to implement a relatively narrow viewing angle, the first backlight unit is operated to be turned on and the second backlight unit is operated to be turned off so that light emitted from the first backlight unit is transmitted to the plurality of slots. After passing through and proceeding toward the image display panel, In order to realize a relatively wide viewing angle, the second backlight unit is turned on so that light emitted from the second backlight unit passes toward the image display panel without passing between the plurality of slots. Display device. The method according to any one of claims 1 to 4, And the plurality of slots extend in a direction perpendicular to a direction for narrowing a viewing angle. In claim 6, The plurality of slots are formed in a grid pattern form.

Images