KR100818478B1 - Stick type back light unit and back light unit assembly using the same - Google Patents

Abstract

A stick type back light unit and a back light unit assembly by using the same are provided to form a groove to a frame, thereby enlarging the freedom of space without piling up a light guide panel when designing backlight unit assembly. An LGP(Light Guide Panel)(21) is formed as a rectangular parallelepiped shape with a rectangular section. Both ends of the LGP are used as light receiving surfaces. An LED(Light Emitting Diode) light source(22) is arranged at the light receiving surface of the LGP so that the light beam is irradiated to the inside of the LGP. A housing(23) surrounds the LGP so that a surface of the LGP parallel to the length-direction is used as a light emission surface. A pyramid pattern(24) is formed at the light receiving surfaces(21b,21c). The housing is a metal thin film made of the material selected from materials with the reflection property such as silver or nickel and the like.

Description

Bar-type backlight unit and backlight unit assembly using the same {STICK TYPE BACK LIGHT UNIT AND BACK LIGHT UNIT ASSEMBLY USING THE SAME}

1A and 1B are structural diagrams of a backlight unit according to the prior art.

2A and 2B are a perspective view and a front view of a bar-shaped backlight unit according to a preferred embodiment of the present invention.

3 is a plan view of a backlight unit assembly in which a bar-shaped backlight unit according to an embodiment of the present invention is disposed in a frame.

4 is a plan view of a backlight unit assembly in which a bar-shaped backlight unit and a fluorescent lamp according to another embodiment of the present invention are disposed in a frame.

<Code Description of Main Parts of Drawing>

21: LGP 22: LED light source

23 housing 24 pyramid pattern

36: frame

The present invention relates to a backlight unit, and more particularly, to a backlight unit having a bar-shaped backlight unit disposed on both ends and the backlight unit using the bar-shaped backlight unit.

Since light-receiving flat panel display elements such as liquid crystal displays (LCDs) do not emit light by themselves, an image can be observed only when light is radiated from the outside. Therefore, a back light unit is installed on the rear surface of the light receiving flat panel display to emit light.

In the case of illuminating a flat panel display device such as a liquid crystal display device, the backlight device is a direct light type in which a plurality of lamps provided directly below the flat display device directly irradiate light onto the liquid crystal panel according to the arrangement of the light source. ) And a lamp installed at a side of the light guide plate is classified into an edge light type that irradiates light and transmits the light to the liquid crystal panel.

1A and 1B are structural diagrams of a backlight unit according to the prior art.

1A is a structural diagram of a backlight unit using a fluorescent lamp (CCFL: Cold light source) as a linear light source. In FIG. 1A, two fluorescent lamps 11 are used to improve the efficiency of the brightness of the backlight unit, and are composed of a housing 12 for condensing the light irradiated from the fluorescent lamps in a predetermined direction.

The housing 12 surrounds the fluorescent lamp. Although not shown, an inverter circuit for supplying power to the fluorescent lamp 11 and a light guide panel for supplying light collected by the fluorescent lamp and the housing to the liquid crystal panel are included.

1B is a structural diagram of a backlight unit using an LED as a point light source.

The backlight unit includes an LED 13 in which monochromatic light sources of at least red, green, and blue wavelengths are arranged in a row, and a housing 12 for condensing the light emitted from the LED in a predetermined direction to reduce power consumption. The housing 12 surrounds the LED 13.

Monochromatic light of red, green and blue wavelengths emitted from the LED 13 is collected by the housing 12 and irradiated to the light guide plate 14 for supplying to the liquid crystal panel. In order for the monochromatic light emitted from the LED 13 to be evenly transmitted throughout the liquid crystal panel, it must be uniformly synthesized before reaching the light guide plate 14.

In the case of using such a LED as a light source, a monochromatic light LED of red, green, and blue wavelengths is used in the light source unit to emit white light. In order to obtain a white light with uniform luminance distribution, additional color combination methods such as controlling each LED individually or adjusting the pattern on the light guide plate.

The backlight unit using the fluorescent lamp according to the prior art has a problem of low color reproducibility, especially red color reproducibility and luminance due to the limitation of light emission characteristics and capacity of the light source itself, and the backlight unit using the LED has a brightness due to the current LED capacity. Since a single color of each of red, green, and blue wavelengths is emitted from the LED, color reproducibility is high, but it is difficult to realize uniform white light and has low luminance.

The present invention, using the red, green, blue LED as a light source in order to solve the problem of color reproduction and brightness of the fluorescent lamp as described above and the uniform white light of the LED and the brightness problem, the characteristics of high color reproduction and high brightness is possible It is an object to provide a backlight unit.

According to the present invention, a light guide plate having a rod shape having a length in one direction longer than a length in the other direction and having both rod-shaped cross-sections provided as light incidence surfaces, and disposed on the light incidence surface of the light guide plate to irradiate light into the light guide plate, respectively. Provided is a bar-shaped backlight unit including an LED light source, and a housing formed to expose one surface of the light guide plate surface to provide one surface of the light guide plate as a light emitting surface.

The light guide plate may have a rectangular cross section in the longitudinal direction, and may have one shape selected from a polygonal shape including a circular, semicircular, or triangular cross section in the longitudinal direction.

In the light incident surface of the light guide plate, a serration may be formed in a region where the LED light source is disposed, and the serration may have a pyramid pattern.

The LED light source may be one monochromatic LED or an array of a plurality of LEDs, and in the case of monochromatic light, it is preferable to use a white light LED, and in the case of a plurality of LED arrays, red (R), green (G), and blue ( B) It is preferable to use a combination of LEDs.

In the housing, it is preferable to use a metal film made of one material selected from materials having excellent reflectivity such as silver (Ag) or nickel (Ni) so that light is focused on the light exit surface of the light guide plate.

In addition, the present invention is a light guide plate having a rod shape having a length in one direction is longer than the length in the other direction, the both ends of the bar shape is provided as a light incident surface, and the light incident surface of the light guide plate to irradiate light into the light guide plate A plurality of bar backlight units including a LED light source disposed respectively, and a housing exposing one surface of the light guide plate surface to provide one surface of the light guide plate as a light exit surface; and a frame in which the plurality of bar backlight units are disposed. It provides a backlight unit assembly comprising.

It is preferable that the plurality of bar-shaped backlight units are arranged so that a part of each light guide plate overlaps.

The backlight unit assembly may further include at least one fluorescent lamp disposed between the plurality of bar-shaped backlight units.

In order to adjust the uniformity of the light, the frame is preferably formed with a groove that can accommodate a portion of the bar-shaped backlight unit disposed on the edge of the frame.

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

2A and 2B are a perspective view and a plan view of a bar backlight unit according to a preferred embodiment of the present invention.

2A and 2B, the backlight unit 20 according to the present invention includes a light guide plate 21 having a rod shape, an LED light source 22, and a housing 23 surrounding the light guide plate.

The light guide plate 21 is manufactured in the form of a rectangular parallelepiped having a rectangular cross section in the longitudinal direction. The shape of the light guide plate 21 may be variously implemented according to the purpose and shape to be implemented. That is, the cross section with respect to the longitudinal direction can be manufactured to have a circular or triangular form.

When the cross section along the longitudinal direction is the cause, the uniformity of the light emitted through the light guide plate increases, whereas when the cross section along the longitudinal direction is a triangle or a square, the efficiency of the emitted light increases. A separate housing may be used to concentrate the light emitted by the light guide plate in one direction.

In addition, in this embodiment, the light guide plate 21 is in the form of a rod having a length in the longitudinal direction longer than that in the other directions. Preferably, the length ratio in the direction different from the length direction may be 5: 1 or more.

Both side surfaces 21b and 21c of the light guide plate 21 serve as light incident surfaces through which light is irradiated from a light source.

Pyramid patterns 24 are formed on the light incident surfaces 21b and 21c. The vertex angle of the pyramid pattern 24 is preferably at least 90 degrees, the pitch of the pyramid pattern may be 10 ~ 100㎛. Such a serration may be implemented in various forms such as a prism pattern.

The upper surface 21a of the light guide plate serves as a light exit surface of light incident from the light entrance surfaces 21b and 21c.

In order for the light to be emitted to the light exiting surface 21a, an angle (hereinafter referred to as "incident angle") formed by the light incident on the light exiting surface with a normal perpendicular to the light exiting surface must be smaller than the critical angle. Therefore, light having an incident angle smaller than the critical angle among the light incident on the light guide plate is emitted through the light exit surface, and the rest is totally reflected and propagated into the light guide plate. Of the light incident on the light guide plate, the light once totally reflected cannot exit the light guide plate unless the incident angle is changed.

Light path converting means may be used to convert such light paths. For example, a scattering pattern for scattering light, a hologram pattern for diffracting light, or the like can be used. The light path converting means may be formed on the light exit surface or the bottom surface opposite thereto.

The light guide plate 21 is made of a light transmitting material capable of transmitting light. Preferably, a transparent resin having a refractive index of 1.49 and a specific gravity of about 1.19 may be used. That is, acrylic, polycarbonate, or the like can be used.

In the case of this embodiment, the light guide plate 21 is made of acrylic. The light guide plate 21 may have a thickness of about 1 to 3 mm, and a wedge shape having a thinner thickness may be used as the light is moved away from a side from which light is incident. The size of the light guide plate depends on the size of the planar image display device, for example, the LCD. In the present embodiment, a light guide plate in the form of a rod having a long length in one direction is used instead of a flat plate.

In this embodiment, the LED light source 22 is used as a light source.

The LED light source 22 may be one LED that emits white light. It can also be a combination of red (R), green (G), and blue (B) light LEDs.

The reason why the LED light source is composed of a plurality of LEDs emitting R, G, and B monochromatic light is that the mixing of R, G, and B colors to produce white light is applied to the liquid crystal display device rather than the case where the LED device emits white light. This is because it is advantageous to implement accurate color reproduction.

In order to optimize color reproducibility and color temperature, the emission spectrum of the backlight must be changed, and correspondingly, the transmission spectrum of the color filter must be adjusted to maximize the emission efficiency.

When using the LEDs of R, G, B to realize the white light at the same time, because the different colors from each LED must be collected, each of the LEDs of R, G, B is required to emit more than a certain intensity.

Therefore, the monochromatic light of each of R, G, and B emitted from the LED is synthesized as white light in the light guide plate 21 before being incident on the liquid crystal display panel to display an image having an accurate color reproducibility.

In this embodiment, a combination of LEDs emitting R, G, and B colors, respectively, can be arranged at both ends of the light guide plate 21 to produce a backlight unit that emits white light.

A housing 23 is formed to cover the remaining area of the light guide plate 21 except for the light exit surface 21a.

The housing 23 is for condensing the light incident from the light input surfaces 21b and 21c onto the light output surface 21a. In this embodiment, except for the upper surface 21a of the light guide plate 21 which is a hexahedron, the housing 23 is formed in the lower surface and front and back surfaces. In addition, the housing 23 is formed in an area of the left and right sides of the light guide plate 21 except for an area facing the LED 22.

The housing 23 may be formed of a metal material capable of reflecting light. Preferably, silver (Ag) foil can be used.

3 is a structural diagram in which a bar-shaped backlight unit according to an embodiment of the present invention is disposed in a frame.

Referring to FIG. 3, the backlight unit assembly 30 according to the present embodiment includes a frame in which a plurality of rod-shaped backlight units are disposed.

The bar backlight unit may have difficulty in arranging a plurality of bar backlights due to poor chromaticity of the end of the bar where the LED light source is disposed when a single backlight unit is used.

In the present embodiment, the plurality of bar-shaped backlight units 31 overlap the ends of the light guide plate with each other so as to increase the uniformity of the entire backlight. The degree of overlap may be adjusted for uniformity, and the distance between the light guide plates on both sides may be properly positioned in consideration of the uniformity of the entire backlight. Although not shown in the drawing, an LED driver for driving the LED is further provided, and the color reproducibility and the brightness may be adjusted by adjusting the driving voltage.

As such, the arrangement of the bar-shaped backlight units in the frame 36 may be implemented in various forms.

In the frame 36 in which the bar backlight unit 31 is disposed, a groove 36a in which a part of the bar backlight unit 31 is inserted is formed at a corner thereof.

When the luminance of the light guide plate itself of the bar-shaped backlight unit 31 is not obtained, the luminance may be obtained by overlapping the light guide plates or adjusting the distance between the light guide plates at a portion other than the edge of the frame 36. have. However, since the corner portion of the frame 36 does not have such a space, a groove is formed in the corner portion to make this space. A part of the bar backlight unit 31 may be disposed in the groove 36a, and the bar backlight unit 31 may be moved along the free space of the groove 36a. The uniformity of light may be controlled by controlling the depth and width according to the degree of uniformity of light emitted from the light guide plate of the bar-shaped backlight unit 31 to secure a space and moving the light guide plate.

The backlight unit assembly according to another embodiment of the present invention may include a plurality of rod-shaped backlight units, a plurality of fluorescent lamps, and a frame in which the backlight unit and the fluorescent lamps are disposed.

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In this embodiment, the fluorescent lamps may be arranged between the bar-shaped backlight units arranged to overlap.

In this embodiment, in order to compensate for the disadvantage of the luminance of the red wavelength of the fluorescent lamp in the conventional backlight unit using only the fluorescent lamp, the light supplied from such a light source can be increased in color reproducibility and luminance.

In this arrangement, the fluorescent lamp and the LED are each provided with an inverter and an LED driver of the fluorescent lamp, so that the color reproduction and luminance can be adjusted by adjusting the respective driving voltages.

As such, the present invention is not limited by the above-described embodiment and the accompanying drawings. That is, the shape of the light guide plate, the arrangement of the LEDs and the arrangement of the bar-shaped backlight units may be variously implemented. It is intended that the scope of the invention be defined by the appended claims, and that various forms of substitution, modification, and alteration are possible without departing from the spirit of the invention as set forth in the claims. Will be self-explanatory.

According to the present invention, it is possible to obtain a backlight unit having a bar light guide plate that is easy to use in addition to the conventional backlight, and high color reproducibility and high brightness can be realized through various arrangements of the bar backlight unit.

In addition, when designing the backlight unit assembly, grooves may be formed in the frame so as to overlap the light guide plates or to overcome the limitation of space, thereby increasing the degree of freedom of space utilization.

Claims (14)

A light guide plate having a rod shape having a length in one direction longer than a length in the other direction and having opposite ends of the bar shape provided as light incidence surfaces, respectively; LED light sources respectively disposed on the light incident surface of the light guide plate to irradiate light into the light guide plate; And A housing formed to expose the one surface to provide one surface parallel to the longitudinal direction of the light guide plate as the light exit surface, The housing, And a metal film made of a material selected from a material having a reflective property such as silver (Ag) or nickel (Ni) so that light is focused onto the light exiting surface of the light guide plate. The method of claim 1, The light guide plate is a bar-shaped backlight unit, characterized in that the cross section with respect to the longitudinal direction. The method of claim 1, The light guide plate is a bar-shaped backlight unit, characterized in that the cross-section in the longitudinal direction is selected from a polygonal shape including a circle, a semi-circle, or a triangle. The method of claim 1, The light incident surface of the light guide plate is Bar-shaped backlight unit, characterized in that the serration is formed in the area where the LED light source is disposed. The method of claim 4, wherein The serration form is a bar-shaped backlight unit, characterized in that the pyramid pattern. The method of claim 1, The LED light source, Bar-shaped backlight unit, characterized in that one monochromatic LED. The method of claim 6, The LED light source, Bar-shaped backlight unit, characterized in that the white light LED. The method of claim 1, The LED light source, Bar-shaped backlight unit, characterized in that the array of a plurality of LEDs. The method of claim 8, The LED array, Bar-shaped backlight unit, characterized in that a combination of red (R), green (G), and blue (B) LED. delete A light guide plate having a rod shape having a length in one direction longer than a length in the other direction, the LED light sources disposed on the light receiving surface of the light guide plate so as to irradiate light into the light guide plate; And a housing configured to expose the one surface to provide one surface parallel to the longitudinal direction of the light guide plate to the light exit surface, wherein the housing includes silver or nickel so as to focus light onto the light exit surface of the light guide plate. A plurality of bar-shaped backlight units, characterized in that the metal film is made of one material selected from reflective materials such as (Ni); And And a frame in which the plurality of bar-shaped backlight units are disposed. The method of claim 11, The plurality of bar-shaped backlight unit, And a portion of each light guide plate is overlapped. The method of claim 11, The backlight unit assembly further comprises at least one fluorescent lamp disposed between the plurality of bar-shaped backlight unit. The method of claim 11, The frame, In order to adjust the uniformity of light, a backlight unit assembly, characterized in that a groove is formed to accommodate a portion of the bar-shaped backlight unit disposed on the edge of the frame.

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