KR20110040034A - Planar light apparatus - Google Patents

Planar light apparatus Download PDF

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Publication number
KR20110040034A
KR20110040034A KR1020090097159A KR20090097159A KR20110040034A KR 20110040034 A KR20110040034 A KR 20110040034A KR 1020090097159 A KR1020090097159 A KR 1020090097159A KR 20090097159 A KR20090097159 A KR 20090097159A KR 20110040034 A KR20110040034 A KR 20110040034A
Authority
KR
South Korea
Prior art keywords
light
light guide
light source
height
guide plate
Prior art date
Application number
KR1020090097159A
Other languages
Korean (ko)
Inventor
박종진
Original Assignee
삼성엘이디 주식회사
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 삼성엘이디 주식회사 filed Critical 삼성엘이디 주식회사
Priority to KR1020090097159A priority Critical patent/KR20110040034A/en
Publication of KR20110040034A publication Critical patent/KR20110040034A/en

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Classifications

    • 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
    • G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
    • G02B6/0055—Reflecting element, 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
    • G02B6/0058—Means for improving the coupling-out of light from the light guide varying in density, size, shape or depth along the light guide
    • 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
    • G02B6/0066—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 characterised by the light source being coupled to the light guide
    • G02B6/0073—Light emitting diode [LED]
    • 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
    • G02B6/0075—Arrangements of multiple light guides
    • G02B6/0078—Side-by-side arrangements, e.g. for large area displays
    • 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

Abstract

PURPOSE: A planar light apparatus is provided to reduce the occurrence of a dark region by optimizing the shape of a light guide plate. CONSTITUTION: A planar light apparatus comprises: plural light guide plates(103) which includes a light-incident unit to which the light from the light source is incident; and plural light sources(101) which are alternatively arranged with the plural light guide plates to emit light on each lateral side of the light guide plate, wherein a light reception unit has the height higher than the light-incident unit and faces the light-incident unit.

Description

Planar Light Source Device {Planar Light Apparatus}

The present invention relates to a surface light source device, and more particularly, a technique for minimizing a dark portion in a side emission type light source device capable of split driving.

In the case of a surface light source device used for a backlight or an illumination device for a liquid crystal display, a cold cathode fluorescent lamp (CCFL) has been conventionally used. However, since CCFL uses mercury gas, it may cause environmental pollution. It is slow, has low color reproducibility, and has disadvantages that are not suitable for light and thin LCD panels. On the other hand, Light Emitting Diodes (LEDs) are environmentally friendly, have fast response times of several nanoseconds, and are effective in video signal streams, enable impulsive driving, and have more than 100% color reproducibility. It is possible to arbitrarily change the brightness, color temperature, etc. by adjusting the amount of light of the red, green, and blue light emitting diodes, and has advantages that are suitable for light and small size reduction of the LCD panel.

The surface light source device may be divided into a direct type (top view) and a side emission type (side view) according to a method of disposing a light source such as a light emitting diode. In the case of the direct type surface light source device, the light emitted from the light source is directly irradiated upward, and the brightness of each area is easily controlled, that is, the division driving is easy, but there is a problem that it is difficult to reduce the thickness of the surface light source device. In the side emission type light source device, a light source is disposed on a side of the light guide plate and a light of a two-dimensional shape is emitted through an upper portion of the light guide plate, and has advantages and disadvantages opposite to the direct type method. That is, in the case of the side emission type light source device, the number of light sources can be reduced and the thickness thereof can be reduced, but it is difficult to implement the split driving.

An object of the present invention is to provide a surface light source device capable of minimizing the generation of the dark portion while the split driving in the side-emitting surface light source device.

In order to achieve the above object, one embodiment of the present invention,

A plurality of light guide plates and a plurality of light sources disposed alternately with the plurality of light guide plates so as to irradiate light toward each side of the plurality of light guide plates, wherein at least one of the plurality of light guide plates has a mouth into which light emitted from the light source is incident; It provides a surface light source device, characterized in that the height of the light portion located opposite the light incident portion is higher than the height of the light portion.

In an embodiment of the present disclosure, at least one of the plurality of light guide plates may gradually increase in height from the light incident portion toward the light facing portion.

In this case, it is preferable that at least one of the plurality of light guide plates increases in height at a constant ratio from the light incidence portion to the light incidence portion.

In one embodiment of the present invention, the height of the light portion may be higher than the height of the light source adjacent thereto.

In one embodiment of the present invention, the light source is disposed on the side of the light guide portion of the plurality of light guide plates may have a height of the light guide portion that is opposite to the light incident portion than the height of the light incident portion.

In one embodiment of the present invention, the light source may further include a circuit board mounted and electrically connected to the light source.

In this case, it is preferable that the light emitting surface of the light source is disposed perpendicularly to the substrate.

In one embodiment of the present invention, at least one of the plurality of light guide plates may include a reflector formed in the light guide portion.

In this case, it is preferable that the reflecting portion is formed at the same height as the light source disposed on the light receiving portion side.

In one embodiment of the present invention, it may further include a reflective layer disposed below the light guide plate.

In one embodiment of the present invention, the light guide plate may further include an optical sheet arranged to change the path of the light incident from the light guide plate.

In one embodiment of the present invention, each of the plurality of light sources may be a light emitting diode array structure.

According to the present invention, by dividing a plurality of light guide plates and a plurality of light sources alternately to implement a split drive in the side-emitting surface light source device, and further, by optimizing the shape of the light guide plate, it is possible to reduce the occurrence of the dark portion.

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

However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. In addition, the embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. Accordingly, the shape and size of elements in the drawings may be exaggerated for clarity, and the elements denoted by the same reference numerals in the drawings are the same elements.

1 is a plan view schematically illustrating a surface light source device according to an exemplary embodiment of the present invention, and FIG. 2 schematically illustrates a cross-sectional view of a line AA ′ in FIG. 1. Referring to FIG. 1, the surface light source device 100 according to the present embodiment has a structure in which the light source 101 is disposed on one side of the light guide plate 103, and in particular, includes a plurality of light guide plates 103. . The light guide plate 103 is separated into a plurality of light guide plates 103 instead of one in order to implement split driving by separately arranging light sources 101 irradiating light to each light guide plate 103. Here, the division driving means that the different current signals can be applied to the different light sources 101 to adjust the brightness separately.

The light source 101 may employ any light emitting device capable of emitting light. However, it is preferable to employ a light emitting diode in terms of light and small size of the surface light source device 101. For example, as an example of the light source 101, as shown in FIG. 2, a package structure in which the light emitting diode 101b is mounted in the package body 101a may be used. In this case, as shown in FIG. 1, the light source 101 may be mounted on the substrate 102 and arranged to form an array. The light source 101 array may be alternately arranged on the side surface of one light guide plate 103, and the light source 101 array may be adjusted in brightness separately from the other arrays for split driving. In addition, even within one light source array 101 it may be possible to adjust the brightness between the light source (101).

As described above, in the case of the surface light source device 100 of the present embodiment, a split drive is implemented along with the inherent advantages of the side-emitting type which realizes a thin thickness of the device. Meanwhile, in the present exemplary embodiment, the light source 101 array and the light guide plate 103 are alternately arranged with each other, but the number of the light sources 101 and the light guide plate 103 are alternately arranged. A structure in which the light source 101 array and the light guide plate 103 are additionally arranged on the right side may also be employed. However, when the split driving is implemented in the side emission type light source device 100, a dark part having a relatively low luminance of light when viewed from the top of the light guide plate 103 is likely to occur. Specifically, the luminance of light may be relatively low in an area where the light guide plate 103 does not exist, that is, an area where the light source 101 is disposed between the two light guide plates 103.

In this embodiment, the shape of the light guide plate is optimized to reduce the occurrence of such a problem. Specifically, referring to FIG. 2, when the light guide plate 103 looks at the arrangement structure in the surface light source device 100, the incident portion I to which light is incident from the light source 101 and the opposing light portion O opposite to the light guide plate 103. It can have Here, the incident part I and the light guide part O are not limited to mean only the longitudinal section of the light guide plate 103, but may be understood to include the longitudinal section and the region adjacent thereto.

In order to achieve the purpose of reducing the dark portion, as shown in FIG. 2, the light guide plate 103 is formed so that the height of the light portion O is higher than that of the light incident portion I. FIG. 3 is an enlarged view of a light guide region of the light guide plate of FIG. 2. Referring to FIG. 3, the light projecting portion O of the light guide plate 103 is formed higher than the light incident portion I and the light source 101, so that light emitted through the upper end of the light projecting portion O may be formed in the light source 101. It can be mixed in the upper portion, thereby increasing the luminance in the region where the conventional dark portion is formed, that is, the upper portion of the light source 101. As another structure for obtaining such an effect, a structure in which the height of the light incident portion I is the same as that of the light incident portion O, that is, a structure in which the height of the light incident portion I and the light facing portion O is higher than that of the light source 101 is obtained. Although it may be considered, in this case, diffuse reflection or the like may occur due to the top of the beach light incident part I emitted from the upper part of the light-receiving part O, and thus the luminance may be further increased in the upper part of the light source 101. have. Therefore, in order to reduce the dark portion and to ensure the uniformity of the overall luminance, the light incident portion I is preferably formed lower than the light facing portion O as in the present embodiment.

In the present embodiment, the height of the light guide plate 103 is increased at a constant rate from the light incidence portion I to the light portion O, which is a structure suitable for obtaining a uniform luminance distribution. However, the present invention is not limited only to the shape of the light guide plate illustrated in FIG. 2, and may be variously changed. 8 shows examples of various shapes of the light guide plate that may be employed in the present invention. Although there may be some disadvantages in terms of uniformity of the luminance distribution, the aspect in which the height of the light guide plate increases from the light incident part I to the light guide part O is increased stepwise as necessary, as shown in FIG. 8. In the case of (a), only a part of which has a constant inclination (c), and a case in which it is increased without having a constant inclination (c) or the like, a structure can also be employed.

Meanwhile, referring back to FIG. 2, the substrate 102 is a circuit board on which a circuit pattern is formed, and the light source 101 is preferably arranged such that the light emitting surface is perpendicular to the substrate 102 in view of the heat radiation effect. Do. Specifically, the substrate 102 may be disposed between the light guide portion O of the light guide plate 103 and the light source 101. However, as in the present embodiment, the substrate 102 is disposed below, and the light source (on the light source (101) is disposed thereon. If the light emitting surface is disposed so that the light emitting surface is perpendicular to the substrate 102, the substrate 102 may be in direct contact with the bottom frame (not shown), so that the heat emitted from the light source 101 may be easily diffused to the outside. will be.

4 is a cross-sectional view schematically showing a surface light source device according to another embodiment of the present invention. Referring to FIG. 4, the surface light source device 200 according to the present embodiment has a structure in which the light source 201 is disposed on one side of the light guide plate 203 as in the previous embodiment, and the plurality of light guide plates 203 are provided. ) And the array of light sources 201 may be alternately arranged to implement split driving. The light guide plate 203 has a shape in which the height of the light guide portion O is higher than that of the light incident portion I, thereby reducing the occurrence of dark portions on the light source 201 disposed between the light guide plates 203. have. The difference from the previous embodiment is that the light guide plate 203 and the light source 201 are closely arranged. That is, as shown in FIG. 4, in the surface light source device 200, the substrate 202 is disposed under the light guide plate 203, and the light guide portion O and the light source 201 of the light guide plate 203 are in close contact with each other. Formed. This close contact structure is advantageous in reducing the size of the surface light source device 200 and lowering the possibility of dark areas.

In the above-described embodiment, the efficiency of the surface light source device can be improved by applying various reflective materials to the periphery of the light guide plate. 5 to 7 are cross-sectional views schematically illustrating the surface light source device according to the modified embodiment of FIG. 4. First, the surface light source device 200 ′ according to the embodiment of FIG. 5 has a structure in which the reflective layer 204 is further employed in the embodiment of FIG. 4. That is, by forming the reflective layer 204 made of a material having Ag, Al, etc. having high light reflecting performance under the light guide plate 203, the intensity of light emitted upward can be further increased. In addition, the light guide plate 203 The release of heat generated at can also be easier. Next, FIG. 6 is a structure in which the reflecting portion 205 is formed in the light portion of the light guide plate 203. By forming the reflector 203 in the light projecting portion, it is possible to minimize the amount of light absorbed or scattered by the light source 201 and lost. In this case, in view of reducing the dark portion on the light source 201, it may be possible to form the reflector 205 ′ at the same height as the height of the light source 201, as shown in FIG. 7.

9 is a sectional views schematically showing a surface light source device according to still another embodiment of the present invention. Referring to FIG. 9, the surface light source device 300 according to the present embodiment has a structure in which the light source 301 is disposed on one side of the light guide plate 303, as in the previous embodiment, and the plurality of light guide plates 303 is used. ) And the array of light sources 301 may be alternately arranged to implement split driving. The light guide plate 303 has a shape in which the height of the light guide portion O is higher than that of the light incident portion I, thereby reducing the occurrence of the dark portion on the light source 301 disposed between the light guide plates 303. have. The difference from the previous embodiment is that the optical sheet 306 is added on top of the light guide plate 303. The optical sheet 306 may have a structure in which a single sheet or a plurality of sheets are stacked, and various kinds of sheets known in the art, such as a diffusion sheet or a prism sheet, may be used. By additionally employing such an optical sheet 306, the luminance of light can be uniform when viewed from the top of the light guide plate 303, so that it can be more advantageously used for a backlight unit or lighting device for a liquid crystal display device.

The present invention is not limited by the above-described embodiment and the accompanying drawings, but is intended to be limited by the appended claims. It will be apparent to those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. something to do.

1 is a plan view schematically illustrating a surface light source device according to an exemplary embodiment of the present invention, and FIG. 2 schematically illustrates a cross-sectional view of a line AA ′ in FIG. 1.

FIG. 3 is an enlarged view of a light guide region of the light guide plate of FIG. 2.

4 is a cross-sectional view schematically showing a surface light source device according to another embodiment of the present invention.

5 to 7 are cross-sectional views schematically illustrating the surface light source device according to the modified embodiment of FIG. 4.

8 shows examples of various shapes of the light guide plate that may be employed in the present invention.

9 is a sectional views schematically showing a surface light source device according to still another embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

101: light source 102: substrate

103: light guide plate 204: reflective layer

205 and 205`: reflecting portion 306: optical sheet

Claims (12)

A plurality of light guide plates; And And a plurality of light sources disposed alternately with the plurality of light guide plates to irradiate light to side surfaces of the plurality of light guide plates, At least one of the plurality of light guide plates is a surface light source device characterized in that the height of the light portion located opposite the light incident portion is higher than the height of the light incident portion incident light emitted from the light source. The method of claim 1, At least one of the plurality of light guide plates is a surface light source device, characterized in that the height of the upper surface gradually increases from the light incident portion toward the light guide portion. The method of claim 2, At least one of the plurality of light guide plate is a surface light source device, characterized in that the height of the upper surface is increased at a constant ratio from the light incident portion toward the light guide portion. The method of claim 1, And the height of the light source is higher than the height of the light source adjacent thereto. The method of claim 1, The light source device of the plurality of light guide plates on which the light source is disposed on the side of the light guide part has a height of the light guide part located opposite to the light guide part than the height of the light guide part. The method of claim 1, And a circuit board on which the light source is mounted and electrically connected to the light source. The method of claim 6, The light source is a plane light source device, characterized in that the light emitting surface is disposed perpendicular to the substrate. The method of claim 1, At least one of the plurality of light guide plates includes a reflector formed in the light guide portion. The method of claim 8, And the reflecting unit is formed at the same height as the light source disposed on the side of the light projecting unit. The method of claim 1, And a reflective layer disposed under the light guide plate. The method of claim 1, And an optical sheet disposed on the light guide plate to change a path of light incident from the light guide plate. The method of claim 1, The plurality of light sources are surface light source device, characterized in that each of the light emitting diode array structure.
KR1020090097159A 2009-10-13 2009-10-13 Planar light apparatus KR20110040034A (en)

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KR1020090097159A KR20110040034A (en) 2009-10-13 2009-10-13 Planar light apparatus

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Application Number Priority Date Filing Date Title
KR1020090097159A KR20110040034A (en) 2009-10-13 2009-10-13 Planar light apparatus

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KR20110040034A true KR20110040034A (en) 2011-04-20

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20170133616A (en) * 2016-05-26 2017-12-06 이명분 Illuminated signboad

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20170133616A (en) * 2016-05-26 2017-12-06 이명분 Illuminated signboad

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