Classifications

• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
  • G02F1/1333—Constructional arrangements; Manufacturing methods
  • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
  • G02F1/133524—Light-guides, e.g. fibre-optic bundles, louvered or jalousie light-guides
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
  • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
  • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
  • G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
  • G02B6/0023—Means for improving the coupling-in of light from the light source into the light guide provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
  • G02B6/0025—Diffusing sheet or layer; Prismatic sheet or layer
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
  • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
  • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
  • G02B6/0033—Means for improving the coupling-out of light from the light guide
  • G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
  • G02B6/0036—2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
  • G02F1/1333—Constructional arrangements; Manufacturing methods
  • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
  • G02F1/1336—Illuminating devices
  • G02F1/133615—Edge-illuminating devices, i.e. illuminating from the side

Definitions

• the present invention relates to a light guide plate used for a liquid crystal display (LCD) , and more particularly to a light guide plate that enhances distribution efficiency of light and provides a slim sized back light unit.
• LCD liquid crystal display
• a back light unit is essentially required for a TFT- LCD.
• the back light unit is used as a light unit that uniformly transmits light to a panel of the LCD.
• the LCD controls an amount of transmitted light so that an image is displayed on the panel of the LCD.
• the LCD has non-emitting characteristic. Therefore, it is difficult to use the LCD in a dark region where no light is provided.
• the back light unit is used to enable the LCD in the dark region and uniformly emits light on a data display panel. Since the back light unit is used as a light source for TFT-LCD of laptop computers, it is required to emit bright light with minimum power as much as possible.
• the back light unit serves to provide light emitted from a light source such as a fluorescent lamp on the panel of the LCD at a uniform brightness.
• a back light unit includes a fluorescent lamp, a reflecting plate reflecting light, a light guide plate, and a diffusing plate.
• the light guide plate serves to uniformly emit light, which is emitted from the fluorescent lamp used as a light source at both sides, on the whole surface of the LCD.
• a related art light guide plate 90 shown in FIG. 9 is formed by layering a horizontal plate 93 with a horizontal prism and a vertical plate 96 with a vertical prism.
• FIG. 1 is a perspective view illustrating a light guide plate according to one embodiment of the present invention
• FIG. 2 is a sectional view taken along line A-A' of
• FIG. 1; FIG. 3 is a partially enlarged front view illustrating a light guide plate of FIG. 1;
• FIG. 4 is a partially enlarged front view illustrating a light guide plate according to another embodiment of the present invention;
• FIG. 5 is an exploded perspective view illustrating an LCD provided in a light guide plate of FIG. 1;
• FIGS. 6 and 7 are sectional views illustrating a lamp reflector provided at both sides of a light guide plate;
• FIGS. 8 and 9 are a perspective view and an exploded perspective view illustrating a related art light guide plate .
• the related art light guide plate has a structure that a horizontal plate and a vertical plate are layered, there is limitation in making a slim sized thin film. In other words, it is important that LCD has a thin film. Therefore, the LCD manufacturers have tried to make a thin film.
• the related art light guide plate has a drawback in making a slim sized LCD because it has a double layered structure.
• the present invention is directed to a light guide plate that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
• An object of the present invention is to provide a light guide plate that uniformly distributes light emitted from a light source on a whole surface of an LCD panel after transmitting a reflector and a light guide plate.
• Another object of the present invention is to provide a light guide plate having a slim size.
• the light guide plate according to the present invention has the following advantages. Since light emitted from a light source is refracted in different directions while transmitting inclined sides of horizontal and vertical prisms, the light is uniformly irradiated on the whole surface of an LCD. Also, the light guide plate can be formed with a thin film having one layered structure unlike the related art light guide plate having a double layered structure.
• a light guide plate which is wholly formed with a horizontal prism and a vertical prism and enhances distribution efficiency of light on the whole surface by refracting light includes a horizontal prism member horizontally formed at one side of the light guide plate, and a vertical prism member vertically formed, the horizontal and vertical prism members being repeatedly formed in turn.
• the horizontal- prism member includes two or three horizontal prisms and vertical prisms, each having a triangle shaped section.
• the triangle shape of the horizontal and vertical prisms has an angle between 40° and 60°.
• a light guide plate in another aspect of the present invention, includes a light source at both sides, and a lamp reflector having a semi-circle shaped section outside the light source to allow light emitted from the light source to be reflected thereon and to be emitted into the light guide plate.
• FIG. 1 is a perspective view illustrating a light guide plate according to one embodiment of the present invention
• FIG. 2 is a sectional view taken along line A-A' of FIG. 1.
• a light guide plate 10 according to the present invention is made of a transparent material transmitting light.
• a horizontal prism member 110 and a vertical prism member 120 are repeatedly formed in turn at one side of the light guide plate 10.
• the horizontal prism member 110 and the vertical prism member 120 are formed in a single body.
• the horizontal and vertical prism members 110 and 120 shown in FIG. 3 include respectively two prisms refracting light.
• the horizontal prism member 110 is provided with two adjacent horizontal prisms 115.
• the vertical prism member 120 is also provided with two adjacent vertical prisms 125.
• the horizontal and vertical prism members 110 and 120 have a square shape when viewed from the front side so that they are closely connected to each other. If they have a rectangular shape not the square shape, a void may be formed because they are not closely connected to each other.
• the light guide plate 10 fails to exert its own function. It is preferable that the sides of the prisms 115 and 125 are inwardly inclined to move upwardly. In other words, the triangle shaped sides of the prisms 115 and 125 are inclined to refract light in different directions, so that the light is uniformly transmitted on the whole surface (see FIG. 3) .
• the triangle shape of the prisms 115 and 125 has an isosceles triangle and an angle between 40° and 60° to uniformly irradiate light on the whole surface .
• the horizontal and vertical prism members 110 and 120 have a square shape when viewed from the front side. FIG.
• FIG. 5 illustrates the state that the light guide plate 10 is provided in the LCD.
• a light source 20 emitting light is provided at both sides of the light guide plate 10.
• a lamp reflector 25 is also provided at both sides of the light guide plate 10.
• the lamp reflector 25 collects light reflected from the light source 20 and reflects the light on the light guide plate.
• the lamp reflector 25 has a semi-circle shape that encircles the light source 20, and has a mirror face thereon .
• the light emitted from the light source 20 is entranced into the light guide plate 10 by the lamp reflector 25.
• a reflecting plate 30 reflecting light is provided to prevent the incident light of the light guide plate 10 from being transmitted to the back side .
• a diffusing plate 40 diffusing light, an LCD 50, and a shielding sheet 60 are sequentially provided at the front of the light guide plate 10.
• the light reflected from the side of the light guide plate 10 and the reflecting plate 30 is reflected by the horizontal prism 115 and the vertical prism 125 so that the light emitted from the light source 20 is uniformly irradiated on the whole surface of the LCD 50 (see FIGS. 6 and 7) .
• the light guide plate 10 is applicable for a sign board used by reflecting light in addition to the LCD.
• FIG. 4 illustrates a light guide plate according to another embodiment of the present invention.
• the light guide plate shown in FIG. 4 includes a horizontal prism member 110 and a vertical prism member 120 each having three prisms.
• a plurality of prisms can be formed in the horizontal and vertical prism members 110 and 120 of the light guide plate 10.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Nonlinear Science (AREA)
• Mathematical Physics (AREA)
• Chemical & Material Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Planar Illumination Modules (AREA)
• Light Guides In General And Applications Therefor (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=34431694

Family Applications (1)

Country Status (2)

Cited By (3)

Families Citing this family (1)

Citations (3)

• 2003
  • 2003-10-13 KR KR1020030071003A patent/KR20050035582A/ko not_active Application Discontinuation
• 2004
  • 2004-09-14 WO PCT/KR2004/002324 patent/WO2005036245A1/en active Application Filing

Patent Citations (3)

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