WO2011126123A1 - 光源モジュール、およびそれを備えた電子機器 - Google Patents
光源モジュール、およびそれを備えた電子機器 Download PDFInfo
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- WO2011126123A1 WO2011126123A1 PCT/JP2011/058945 JP2011058945W WO2011126123A1 WO 2011126123 A1 WO2011126123 A1 WO 2011126123A1 JP 2011058945 W JP2011058945 W JP 2011058945W WO 2011126123 A1 WO2011126123 A1 WO 2011126123A1
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- light
- guide plate
- light guide
- light source
- source module
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- 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
- G02B6/0068—Arrangements of plural sources, e.g. multi-colour light sources
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- 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
- G02B6/0038—Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
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- 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]
Definitions
- the present invention relates to a light source module and an electronic apparatus including the same, and more specifically, for example, in a liquid crystal display device, a side edge that emits light from a light source in a planar shape by a light guide plate in order to reduce the thickness.
- the present invention relates to a light source module used for a backlight including a type light guide plate (also referred to as a side light), and an electronic apparatus including the light source module.
- a backlight having a side edge type light guide plate that emits light from a light source in a planar shape by a light guide plate is frequently used.
- FIG. 11 is a diagram showing the planar illumination device of Patent Document 1.
- a prismatic structure is formed on the main surface of the light guide plate 101.
- a plurality of LED light sources 102 are provided in the vicinity of the end surface 111 orthogonal to the main surface.
- the light incident from the end surface 111 of the light guide plate 101 is a prism-like structure provided on the main surface of the light guide plate 101. Due to the action of the body, the light propagates in the left direction in FIG. 11 without substantially spreading in the vertical direction in FIG.
- FIG. 12 is a cross-sectional view showing the configuration of the prismatic structure 110 in the planar illumination device of Patent Document 1.
- a dot-like white reflecting surface or the like is formed on a flat surface and illuminated uniformly.
- Patent Document 2 discloses a configuration in which a V-groove is formed on the surface opposite to the exit surface of the light guide plate.
- Japanese Patent Publication Japanese Unexamined Patent Application Publication No. 2009-283383 (Released on Dec. 3, 2009)” Japanese Patent Publication “JP 2009-31445 A (published February 12, 2009)”
- planar illumination device of Patent Document 1 has the following problems.
- the prismatic structure 110 in the planar illumination device of Patent Document 1 has a very high confinement effect for confining light in the light guide plate for light having a specific angle ⁇ .
- the confinement effect is not exerted on the light C incident at a shallow angle (the angle ⁇ with the flat surface is small).
- the light C incident at a shallow angle has a large spread in the straight direction (longitudinal direction of the light guide plate) and the vertical direction (short direction of the light guide plate). For this reason, as shown in FIG. 12, the component of the light C that reflects in the direction directly below the prism surface outside the illumination area 103 increases.
- the component reflected in the direction directly below the prism surface is scattered on the flat surface and emitted from the prismatic structure 110.
- the light C incident at a shallow angle (the angle ⁇ with the flat surface is small) may be emitted from a position shifted from the illumination region 103.
- the illumination area 103 extends in a direction (short direction) perpendicular to the straight light traveling direction (longitudinal direction).
- the present invention has been made in view of the above-described conventional problems, and an object thereof is a light source module capable of suppressing the spread of light in a direction (longitudinal direction) perpendicular to a straight traveling direction (longitudinal direction). And providing an electronic apparatus including the same.
- the light source module of the present invention includes a light guide plate, a plurality of light sources that allow light to enter from at least one end face in the longitudinal direction of the light guide plate, and a light emission surface of the light guide plate.
- a light source module including a plurality of optical path conversion units for extracting light guided inside the light guide plate on a surface opposite to the light guide plate, and in a longitudinal direction on a light exit surface of the light guide plate It is characterized by having a plurality of curved surface structure parts composed of curved surfaces having ridge lines.
- the light exit surface of the light guide plate has a plurality of curved surface structure portions formed of curved surfaces having ridge lines in the longitudinal direction. That is, the plurality of curved surface structure portions are formed along the longitudinal direction.
- a plurality of optical path conversion units for taking out light guided inside the light guide plate is formed on the surface opposite to the light exit surface of the light guide plate. In the optical path conversion unit, the angle component of the light beam guided through the light guide is converted, and the light beam that breaks the total reflection condition in the longitudinal direction and the short direction can be emitted from the light guide.
- the curved surface structure portion has a curved surface whose surface shape is continuously changed with respect to the short side direction.
- the light whose light path has been converted by the light path conversion unit can efficiently extract for light whose total reflection conditions are broken in the longitudinal direction of the exit surface. become. That is, the light whose total reflection condition is broken in the longitudinal direction of the emission surface is emitted from the light guide plate without being totally reflected by the emission surface even when incident at various angles in the short direction of the emission surface.
- the light whose optical path has been converted by the optical path converter the light whose total reflection condition is not broken in the longitudinal direction of the exit surface does not exit from the light guide plate, but spreads the light component in the short direction.
- the inside of the light guide plate is guided in a suppressed state. Therefore, according to said structure, the light source module which can suppress the spreading to the direction (short side direction) perpendicular
- the schematic structure of the light source module of this invention is shown, (a) is a top view, (b) is a side view. It is a disassembled perspective view which shows the structure of the liquid crystal display device provided with the said light source module. It is sectional drawing which shows a part of structure in a liquid crystal display device provided with the said light source module.
- (A) shows a diffusion image of one microlens in the microlens group, the left side is a schematic diagram showing scattering characteristics in the xz plane, and the right side shows scattering characteristics in the yz plane.
- FIG. 4B is a schematic diagram showing a diffusion image of a diffusing material (scatterer), the left side is a schematic diagram showing scattering characteristics on the xz plane, and the right side is scattering characteristics on the yz plane. It is a schematic diagram which shows.
- (A) is sectional drawing which shows the structure of the light-guide plate in which the curved-surface structure and the microlens group were formed
- (b) is sectional drawing which shows the structure of the light-guide plate in which the curved-surface structure and the scatterer were formed. It is. The relationship between the presence or absence of a curved structure in the light guide plate and the illuminance distribution on the exit surface is shown.
- (A) shows the two-dimensional illumination distribution on the exit surface when the light guide plate has a curved structure
- (B) shows a two-dimensional illuminance distribution on the exit surface when the light guide plate has no curved surface structure
- (c) shows the configurations of (a) and (b) at the center of the light guide plate.
- FIG. 1 Shows a case where a prism with an apex angle of 90 ° is formed on the exit surface (conventional example 1), and (c) shows a case where a prism with an apex angle of 5 ° is formed on the exit surface of the light guide plate (conventional example 2).
- (D) shows another structure of the curved-surface structure 20a shown to (a). It is a side view which shows the side shape of the X direction in a light-guide plate, (a) shows the case where the height of a curved-surface structure is small, (b) shows the case where the height of a curved-surface structure is large.
- (a) is the light-guide plate (C) which formed the curved-surface structure on condition that height H / space
- It is sectional drawing which shows schematic structure of the structure I
- (b) is a schematic structure of the light-guide plate (structure II) which made the space
- (c) is a graph showing that when the ratio of height H / interval P is the same, the effect of light confinement does not change when the interval P is halved.
- FIG. It is a schematic diagram for demonstrating the backlight blinking in a light source module. It is a graph which shows the correlation with aspect ratio H / P of the height H and the space
- FIG. 2 is an exploded perspective view of a liquid crystal display device (electronic device) including the light source module of the present embodiment.
- a liquid crystal display device 1 as an electronic apparatus including the light source module 10 according to the present embodiment includes a chassis 2, a light source module 10, a liquid crystal panel 3, and a bezel 4 in order from the bottom as shown in FIG.
- the light source module 10 includes a reflection sheet 11 as a reflection plate, an LED (Light-Emitting Diode) 12 and LED substrate 13 as a light source, a reflector 14, a light guide plate 20, a diffusion plate 15, and an optical sheet group 16. It is composed of Note that the diffusion plate 15 and the optical sheet group 16 may not exist in the present invention.
- FIG. 3 is a cross-sectional view showing a part of the configuration of the liquid crystal display device 1 including the light source module 10.
- the LED 12, the LED substrate 13, and the reflector 14 are provided at the end portion of the light guide plate 20, so that light from the LED 12 is incident on one end surface 21 a of the light guide plate 20 and guided.
- the liquid crystal panel 3 is irradiated with light from the exit surface 20 d of the light plate 20 through the diffusion plate 15 and the optical sheet group 16. Therefore, the light source module 10 of the present embodiment employs a side edge (also referred to as side light) method. Light is emitted from the light guide plate 20 from other surfaces than the exit surface 21d.
- the reflective sheet 11 is disposed on the light guide plate 20 on the surfaces other than the exit surface 20d and the LED 12 and is guided again. Since the light enters the optical plate 20, most of the light is emitted from the exit surface 21d.
- the longitudinal direction of the light guide plate 20 is the X direction
- the normal direction of the light guide plate 20 is the Z direction
- the direction perpendicular to the X direction and the Z direction is the Y direction.
- the Y direction can also be said to be a short direction with respect to the longitudinal direction (X direction) of the light guide plate 20.
- FIG. 1 shows a schematic configuration of a light source module 10 according to the present embodiment.
- FIG. 1 (a) is a top view
- FIG. 1 (b) is a side view.
- LEDs L1 to L5 and LEDs R1 to R5 are arranged as LEDs 12 that allow light to enter from both ends in the longitudinal direction of the light guide plate 20, respectively.
- the LEDs L1 to L5 are arranged so as to face the LEDs R1 to R5 in the longitudinal direction, respectively.
- the light source module 10 includes a light source controller that selectively lights (selectively lights) LEDs L1 to L5 and LEDs R1 to R5.
- the light source control unit can also control to turn on all the light sources of LEDs L1 to L5 and LEDs R1 to R5.
- a curved surface structure 20 a formed of a curved surface is formed on the light exit surface (upper surface) 20 d of the light guide plate 20.
- the curved surface structures 20 a are formed as a streak pattern along the longitudinal direction (X direction) of the light guide plate 20.
- the light guide plate 21 includes a plurality of curved surface structures (curved surface structure portions) 20a each having a curved surface having a ridge line 20e in the longitudinal direction on the light exit surface 20d.
- the curved structure 20a is a structure formed on the light exit surface 20d itself of the light guide plate 20 (a structure formed on the light guide plate 20 itself), and the light guide plate 20 is a member different from the light guide plate 20. A curved structure member is not provided.
- the curved structure 20a formed on the light guide plate 20 has a height in the direction perpendicular to the light exit surface of the light guide plate 20 as H, and an interval between the curved structures 20a as P. ,
- the aspect ratio H / P in the range of 0.2 to 0.5, fluctuations in the amount of crosstalk with respect to the aspect ratio (value indicating superiority or inferiority of light straightness) can be reduced, and the characteristics of the light source module Variation can be suppressed.
- FIG. 14 is a graph showing the correlation between the aspect ratio H / P of the height H and the interval P, and the light straightness.
- the amount of crosstalk (%) of the emitted light between the LEDs adjacent to each other is adopted as a parameter indicating the superiority or inferiority of the light straightness. The smaller the amount of crosstalk, the higher the light straightness.
- the graph shown in FIG. 14 is a result of using the light guide plate 20 having a length of 60 inches in the longitudinal direction and a thickness of 3 mm.
- the crosstalk amount increases as the aspect ratio decreases. That is, the light straightness decreases as the aspect ratio decreases.
- the aspect ratio H / P ⁇ 0.2 the crosstalk amount varies greatly with respect to the aspect ratio, and the crosstalk amount itself is relatively large.
- the variation of the crosstalk amount (light straightness) with respect to the aspect ratio is relatively small, and the crosstalk amount itself is small.
- the aspect ratio H / P in the curved structure 20a is 0.2 ⁇ H / P ⁇ 0.5 It can be seen that it is preferable that the configuration satisfies the above. If the aspect ratio is in the range of 0.2 to 0.5, the variation in light straightness can be reduced. Further, even when there is a deviation in the shape of the curved structure 20a, the light straightness does not vary greatly.
- the aspect ratio H / P 0.5, the shape of the curved structure 20a corresponds to a semi-cylindrical shape.
- a microlens group is provided on the lower surface 20c of the light guide plate 20 opposite to the curved structure 20a (surface opposite to the exit surface 20d; back surface) as an optical path conversion unit. 20b is formed.
- the micro lens group 20 b is a lens group that extracts light guided by the light guide plate 20. That is, the microlens group 20b converts the optical path of the light guided inside the light guide plate 20 and extracts it to the exit surface 20d side.
- the microlens group 20b is formed so that the light emitted from the emission surface 20d of the light guide plate 20 is uniform.
- the microlenses constituting the microlens group 20b are arranged at the same interval. The interval between the microlenses is smaller than the interval P between the curved surface structures 20a, specifically, 85 ⁇ m.
- the optical path conversion unit is the microlens group 20b.
- the present invention is not limited to this configuration, and any optical path conversion unit may be used as long as it converts the optical path of the light guided inside the light guide plate 20.
- the optical path conversion unit may be a scatterer that scatters (diffuses) light guided inside the light guide plate 20.
- the optical path conversion unit has a configuration in which white pattern scatterers are scattered on the lower surface 20 c of the light guide plate 20.
- the shape of the scatterer is not limited to a point shape, and may be formed from a linear white pattern, a prism, or the like.
- the white pattern scatterer can be formed by, for example, screen printing.
- the prism-shaped scatterer can be formed by extrusion molding, injection molding, press working, or the like.
- the optical path conversion unit is preferably the microlens group 20b in order to ensure the directivity of light extracted toward the exit surface 20d.
- the microlens is a structure formed on the light guide plate 20 by a resin having substantially the same refractive index as that of the light guide plate 20.
- the microlens shown in the present embodiment can be formed by coating the light guide plate 20 with an ink jet device and performing UV curing. By applying with an inkjet apparatus, high positional accuracy and fine application are possible, and uniform pattern printing is possible regardless of wide and narrow relations.
- the diameter of a single microlens is controlled in the range of 0 ⁇ m (corresponding to the case without microlens coating) and about 30 to 70 ⁇ m, and the pitch is 85 ⁇ m.
- the refractive index of the microlens is the same as the refractive index of the light guide plate material, but there is no problem in securing the directivity of the light extracted within the range of the refractive index of the light guide plate material ⁇ 10%. It is confirmed that good results with almost no unnecessary scattering can be obtained with a refractive index of ⁇ 3% of the light guide plate material.
- an optical path changing part in the light guide plate 20 there is also an ink path containing a diffusing material (scatterer).
- the scatterer can be formed by screen printing using a mask, but each pattern cannot be made very small to the same extent as a microlens.
- FIG. 4A shows a diffusion image of one microlens 20b1 in the microlens group 20b, the left side is a schematic diagram showing the scattering characteristics in the xz plane, and the right side is in the yz plane. It is a schematic diagram which shows the scattering characteristic.
- 4B shows a diffusion image of the diffusing material (scattering body), the left side is a schematic diagram showing the scattering characteristics in the xz plane, and the right side is the scattering characteristics in the yz plane. It is a schematic diagram which shows.
- the microlens 20b1 serving as the optical path changing unit has the same refractive index as that of the light guide plate 20, the optical path is changed by refraction and reflection on the microlens surface. Therefore, as shown in FIG. 4A, the light whose path has been changed by the microlens 20b1 is the traveling direction of the light beam (X direction in the figure) and the direction perpendicular to the traveling direction (Y direction in the figure). The optical path conversion by angle conversion in the z direction is mainly performed. Therefore, the microlens 20b1 as the optical path conversion unit maintains the directivity of the light beam, and can improve the straightness of the light beam in the light guide plate 20.
- the light beam after the optical path conversion is scattered at a wide range of angles compared to the microlens 20b1 due to the optical path conversion by the irregular reflection of the light beam by the diffusing material.
- the probability that the effect of confining light in the short direction due to the effect of the curved structure 20a formed on the light emitting surface of the light guide plate 20 is not inferior to that of the microlens.
- FIG. 5A is a cross-sectional view showing the configuration of the light guide plate 20 on which the curved surface structure 20a and the microlens group 20b are formed.
- FIG. 5B is a cross-sectional view showing a configuration of the light guide plate 20 on which the curved structure 20a and the scatterer 20f are formed.
- the scatterer 20f cannot make each pattern so small as the microlens 20b1. Therefore, as shown in FIG. 5B, when the scatterer 20f is formed as an optical path changing unit, the scatterer 20f is larger than the curved structure 20a depending on the size of the curved structure 20a. There is.
- the light guide plate 20 has the lower surface 20c formed with the microlens group 20b for extracting light toward the exit surface 20d, and the exit surface 20d formed with the curved structure 20a. It is a configuration. According to this configuration, the spread of light in the short direction (Y direction) is suppressed by the curved structure 20a while ensuring the directivity of the light extracted toward the exit surface 20d of the light guide plate 20 by the microlens group 20b. Can do. Therefore, light straightness in the light guide plate 20 can be improved.
- FIG. 6 is a graph showing the relationship between the presence or absence of the curved structure 20a in the light guide plate 20 and the illuminance distribution on the exit surface.
- 6A shows a two-dimensional illuminance distribution on the exit surface 20d (XY plane) when the light guide plate 20 has the curved structure 20a
- FIG. 6C shows a two-dimensional illuminance distribution on the exit surface 20d (XY plane) when there is no curved structure 20a
- FIG. 6C shows the configuration of FIG. 6A and FIG. 6B.
- the illuminance distribution of the Y direction in the center part of a light-guide plate is shown.
- 6A to 6C the LEDs L3 and LEDR3 in FIGS. 1A and 1B are selectively lit.
- the curved surface structure 20a when the curved surface structure 20a is formed on the exit surface 20d of the light guide plate 20, the light emitted from the LEDs L3 and LEDR3 is the effect of the curved surface structure 20a.
- the light which has guided the inside of the light-guide plate 20 is taken out to the output surface 20d side by the micro lens group 20b. That is, light is emitted from a specific irradiation region (region corresponding to LEDL3 and LEDR3) on the emission surface 20d of the light guide plate 20 by selectively lighting the LEDs L3 and LEDR3.
- the accuracy can be determined from the region corresponding to the selected LED on the exit surface 20d of the light guide plate 20.
- Light can be emitted (extracted) well. That is, by selecting the LED to be lit, the light irradiation area on the light exit surface 20d of the light guide plate 20 can be controlled.
- the liquid crystal display device 1 has a problem of blurring of moving images as compared with a CRT (Cathode-Ray Tube) display device. That is, in the CRT display device, since there is a non-light emission period in which this pixel does not emit light between the light emission period of the pixel in a certain frame and the light emission period of this pixel in the next frame, there is little afterimage feeling. On the other hand, since the display method of the liquid crystal display device 1 is a “hold type” that does not have such a non-light emitting period, an afterimage feeling is generated, and this afterimage feeling is recognized by the user as blurring of a moving image.
- a CRT Cathode-Ray Tube
- the light source module 10 that is a backlight is divided and sequentially turned off in synchronization with the timing of applying the video signal to the liquid crystal panel 3.
- Backlight blinking which is a technique for inserting a black display between them, has been proposed. Thereby, pseudo-impulse type display can be realized, the afterimage feeling can be suppressed, and the power consumption can be reduced.
- FIG. 13 is a schematic diagram for explaining backlight blinking in the light source module 10.
- the light source module 10 includes a light source control unit 23.
- the liquid crystal display device 1 including such a light source module 10 is selectively selected by the light source control unit 23 so that an area corresponding to the video signal is illuminated in synchronization with vertical scanning within one frame of the video signal.
- the LED can be lit for a certain time. Therefore, only a specific portion of the light guide plate 20 can be appropriately blinked to improve moving image characteristics.
- the LEDs 12 positioned at both ends in the longitudinal direction of the light guide plate 20 are also divided into five blocks corresponding to the scan frames 22a to 22e.
- Each of the five blocks in the LED 12 includes an LED arranged on the left side in the longitudinal direction of the corresponding scan frame among L1 to L5 and an LED arranged on the right side in the longitudinal direction of the corresponding scan frame among R1 to R5. Yes.
- the block of the LED 12 corresponding to the scan frame 22d is composed of L3 and L4.
- each frame can be selectively lit in synchronization with the vertical scanning in one frame of the video signal, and the moving image characteristics can be improved.
- FIG. 7 is a cross-sectional view showing a short direction path of light guided inside the light guide plate.
- FIG. 7A shows a case where the curved surface structure 20a is formed on the exit surface of the light guide plate 20 (implementation).
- 7 (b) shows a case where a prism having an apex angle of 90 ° is formed on the exit surface of the light guide plate 20 (conventional example 1)
- FIG. 7 (c) shows the light guide plate 20
- FIG. 7 (d) shows another configuration of the curved surface structure 20a shown in FIG. 7 (a). Show.
- the ratio H / P between the height H and the interval P is 0.4.
- the X direction component is an angle at which the total reflection condition is broken.
- the surface shape of the curved structure 20a shown in FIG. 7A continuously changes (relative to the short direction), it is effective for extracting light incident on the exit surface at various angles. It is working. Therefore, as shown in FIG. 7A, light is efficiently emitted for various incident angles from vertical light A rising perpendicular to the short direction to light C guided at a shallow angle. The light can be taken out and emitted from the emission surface. In addition, the light C guided at a shallow angle is likely to be totally reflected when it is incident on a surface near horizontal (it is difficult to break the total reflection condition). However, in the shape shown in FIG.
- the nearly horizontal surface is formed in the upper part of the semi-cylinder, and is located in a portion where the light C is not easily irradiated. Therefore, the light C guided at a shallow angle is irradiated onto a surface inclined with respect to the short-side direction, so that the total reflection condition is easily broken.
- the microlens group 20a as the optical path conversion unit converts the optical path of the light guided inside the light guide plate 20 and extracts it to the emission surface 20d side. Since the microlens group 20a efficiently induces the vertical light A shown in FIG. 7A, the effect of the curved structure 20a is further improved. On the other hand, when a prism is formed on the exit surface of the light guide plate 20 as shown in FIGS. 7B and 7C, the effect is reversed and light cannot be efficiently emitted from the light guide plate.
- the curved structure 20a shown in FIG. 7A is a structure having a convex cylinder surface protruding from the light exit surface of the light guide plate 20.
- the curved surface structure 20a shown in FIG. 7D is a structure having a concave cylinder surface that is recessed with respect to the exit surface of the light guide plate 20.
- the vertical light A does not become return light due to total reflection.
- the curved surface structure 20a shown in FIG. 7D efficiently emits light from the light guide plate as compared with the configuration shown in FIGS. 7B and 7C. Is possible.
- the shape shown in FIG. 7A is easier to secure the cross-sectional area than the prism shape. Therefore, in the configuration in which the curved structure 20a is formed on the exit surface of the light guide plate 20, the light coupling efficiency at the light incident surface from the LED is high, and light leakage hardly occurs.
- the light source module 10 of the present embodiment when used as a planar illumination such as a backlight, it is general that various optical sheets are arranged directly above the light guide plate 20. Therefore, if the exit surface of the light guide plate 20 has a sharp shape like a prism, the optical sheet may be damaged by rubbing or the like. On the other hand, when the curved structure 20a is formed on the exit surface of the light guide plate 20, there is no possibility that the optical sheet is damaged by rubbing or the like.
- the shape of the curved structure 20a will be described in more detail. So far, the case where the shape of the curved structure 20a is a convex cylinder shape has been described. However, the shape of the curved structure 20a only needs to include a circular arc in a cross-sectional shape perpendicular to the longitudinal direction (X direction). A part of the shape may be a straight line. Such a shape can be formed by pressing the light guide plate 20.
- FIG. 8 is a side view showing a side shape of the light guide plate 20 in the X direction.
- FIG. 8A shows a case where the height H of the curved structure 20a is small, and FIG. The case where the height H of the curved surface structure 20a is large is shown.
- 8A and 8B the interval P between the curved structures 20a and the thickness T of the light guide plate 20 are the same.
- the light from the LED is incident on the side surface of the light guide plate 20 in the longitudinal direction.
- the incident area becomes small. Light leaks from the shaded area in FIG. 8B, and the optical coupling efficiency decreases.
- FIG. 8A when the height H of the curved structure 20a is small in the light incident surface shape (side surface shape in the X direction of the light guide plate 20), the incident area becomes large and the gap Light leakage can be reduced and the optical coupling efficiency can be improved.
- the optical coupling efficiency and light leakage at the light incident surface decrease as the height H of the curved structure 20a increases. Approximately, when the height H of the curved structure 20a is doubled, the amount of light leakage is doubled and the loss of optical coupling efficiency is also doubled.
- the height H of the curved structure 20a is preferably 10% or less of the thickness T of the light guide plate 20.
- the coupling efficiency is greatly reduced (light leakage is about 5% of incident light), which is not preferable.
- the curved structure 20a may not be manufactured unless the height H is 5% or more of the thickness T. That is, when the light guide plate 20 is thin, it is difficult to produce the curved structure 20a when the range of the height H of the curved structure 20a is 5% or less of the thickness T.
- the height H of the curved structure 20a is more preferably 5% or more and 10% or less of the thickness T of the light guide plate 20.
- the thickness T of the light guide plate 20 is 4.2 mm
- the height H of the surface structure 20a is 0.2 mm.
- the confinement effect of confining light in the light guide plate 20 is reduced when the interval P is made constant and the height H is reduced in the curved structure 20a.
- FIG. 9A shows a schematic configuration of the light guide plate 20 (configuration I) in which the curved structure 20a is formed under the condition that the height H / interval P is 0.4 with respect to the thickness T of the light guide plate 20.
- FIG. 9B is a cross-sectional view of the light guide plate 20 (Configuration II) in which the pitch is P / 2 and the height is H / 2 in the curved structure 20a of FIG. 9A. It is sectional drawing which shows schematic structure. As shown in FIGS.
- FIG. 9C is a graph showing that when the ratio of height H / interval P is the same, the effect of light confinement does not change when the interval P is halved.
- the interval P between the curved structures 20a is 0.4 mm
- the height H of the curved structures 20a is 0.16 mm
- the thickness T of the light guide plate 20 is 4.2 mm. The light guide plate is used.
- a light guide plate is used in which the interval P of the curved structure 20a is 0.2 mm, the height h of the curved structure 20a is 0.08 mm, and the thickness T of the light guide plate 20 is 4.2 mm.
- the semi-cylindrical shape of the curved surface structure 20a is similarly halved.
- the configuration including the single light guide plate 20 has been described.
- the light source module 10 of the present embodiment is not limited to this configuration.
- the light guide plate 20 is divided into a plurality of light guides 21... And the plurality of light guides 21.
- a configuration in which gaps 22 are provided in parallel may be employed.
- the LED 12 allows light to enter from one end face 21 a in the longitudinal direction of each light guide 21.
- it is not necessarily limited to one end surface 21a, but may be incident from the other end surface in the longitudinal direction, and light may be incident from both one end surface 21a and the other end surface. That is, in the present invention, it is sufficient that light is incident from at least one end face 21a.
- the light source module according to the present invention has a configuration in which a plurality of curved surface structures each having a curved surface having a ridge line in the longitudinal direction are provided on the light exit surface of the light guide plate.
- the electronic device of this invention is the structure provided with the said light source module as mentioned above.
- the height of the curved surface structure portion is H and the interval between the curved surface structure portions is P
- the height H and the interval P are: 0.2 ⁇ H / P ⁇ 0.5 It is preferable to satisfy.
- the curved surface structure portion has its tangent slope continuously changing. Therefore, it works effectively in terms of the effect of extracting light incident on the exit surface at various angles and the effect of suppressing the spread of light in the short direction.
- the height H and the interval P are set so as to satisfy 0.2 ⁇ H / P ⁇ 0.5. Therefore, when the light guide plate having the curved structure portion is mass-produced, As a result, the efficiency can be improved, and the variation of the characteristics with respect to the shape shift can be suppressed.
- H / P the aspect ratio of the height H and the interval P
- the crosstalk amount with respect to the aspect ratio the superiority or inferiority of light straightness is shown (Value) Value
- the interval between the optical path changing portions is smaller than the interval between the ridge lines.
- the interval between the optical path changing portions is smaller than the interval between the ridge lines, it is possible to further suppress the spread of light in the direction perpendicular to the straight direction (longitudinal direction).
- a light source control unit for selectively lighting the plurality of light sources is provided.
- the light source control unit that selectively turns on the plurality of light sources. Therefore, for example, when applied to a liquid crystal display device as an electronic device, the light source control unit selectively fixes the light source so that an area corresponding to the video signal is illuminated in synchronization with vertical scanning within one frame in the video signal.
- the light is turned on for a long time, only a specific part of the light guide plate can be appropriately blinked to improve the moving image characteristics.
- the optical path conversion unit is preferably a microlens.
- the electronic device of the present invention is characterized by including the above-described light source module in order to solve the above-described problems.
- the height of the curved structure portion is H and the thickness of the light guide plate is T
- the height H of the curved structure portion is 10% of the thickness T of the light guide plate. The following is preferable.
- the height H of the said curved-surface structure part is 10% or less of the thickness T of the said light-guide plate, the light leakage from the clearance gap between curved-surface structure parts can be reduced, and optical coupling efficiency is improved. Can be improved.
- the electronic apparatus of the present invention is characterized by including the above-described light source module.
- the present invention relates to a light source module including a side edge (also referred to as sidelight) type light guide plate that emits light from a light source in a planar shape by a light guide plate, and an electronic device including the same, for example, a backlight. It can be applied to electronic devices such as light source modules and liquid crystal display devices.
- Liquid crystal display device (electronic equipment) 10
- Light source module 12
- LED light source
- Light guide plate 20a Curved surface structure (curved surface structure)
- Micro lens group optical path conversion unit
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Planar Illumination Modules (AREA)
- Light Guides In General And Applications Therefor (AREA)
- Liquid Crystal (AREA)
Abstract
Description
0.2<H/P<0.5
を満たす構成になっていることが好ましい。すなわち、H/P(高さH及び間隔Pのアスペクト比)は、0.2~0.5の範囲であることが好ましい。より好ましくは、アスペクト比H/Pは、0.3~0.4の範囲である。アスペクト比H/Pを0.2~0.5の範囲に設定することにより、アスペクト比に対するクロストーク量(光直進性の優劣を示す値)の変動を小さくすることができ、光源モジュールの特性変動を抑えることができる。
0.2<H/P<0.5
を満たす構成になっていることが好ましいことがわかる。アスペクト比が0.2~0.5の範囲内であれば、光直進性の変動を小さくすることができる。また、曲面構造体20aの形状にずれがあった場合でも、光直進性が大きく変動することがない。なお、アスペクト比H/P=0.5である場合、曲面構造体20aの形状は半円筒形状に相当する。
0.2<H/P<0.5
を満たすことが好ましい。
10 光源モジュール
12 LED(光源)
20 導光板
20a 曲面構造体(曲面構造部)
20b マイクロレンズ群(光路変換部)
20c 下面
20d 出射面
20e 稜線
21a 端面
22a~22e スキャンフレーム
23 光源制御部
Claims (7)
- 導光板と、
上記導光板における長手方向の少なくとも一方の端面から光をそれぞれ入射させる複数の光源と、
上記導光板における光の出射面と反対の面に、上記導光板の内部にて導光される光を取り出すための複数の光路変換部とを備えた光源モジュールであって、
上記導光板における光の出射面に、長手方向に稜線を有する曲面で構成された曲面構造部を複数有することを特徴とする光源モジュール。 - 上記曲面構造部の高さをHとし、上記曲面構造部同士の間隔をPとしたとき、高さH及び間隔Pは、
0.2<H/P<0.5
を満たすことを特徴とする請求項1に記載の光源モジュール。 - 上記光路変換部の間隔は、上記稜線の間隔よりも小さくなっていることを特徴とする請求項1または2に記載の光源モジュール。
- 上記複数の光源を選択的に点灯する光源制御部を備えたことを特徴とする請求項1~3の何れか1項に記載の光源モジュール。
- 上記光路変換部は、マイクロレンズであることを特徴とする請求項1~4の何れか1項に記載の光源モジュール。
- 上記曲面構造部の高さをHとし、上記導光板の厚さをTとしたとき、
上記曲面構造部の高さHは、上記導光板の厚さTの10%以下であることを特徴とする請求項1~5の何れか1項に記載の光源モジュール。 - 請求項1~6の何れか1項に記載の光源モジュールを備えたことを特徴とする電子機器。
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
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US13/520,688 US20120275188A1 (en) | 2010-04-09 | 2011-04-08 | Light source module and electronic apparatus provided with same |
CN201180010312.5A CN102782395B (zh) | 2010-04-09 | 2011-04-08 | 光源组件及具备该光源组件的电子设备 |
EP11766023A EP2557354A1 (en) | 2010-04-09 | 2011-04-08 | Light source module and electronic apparatus provided with same |
Applications Claiming Priority (4)
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JP2010090955 | 2010-04-09 | ||
JP2010-090955 | 2010-04-09 | ||
JP2011-037572 | 2011-02-23 | ||
JP2011037572A JP5068865B2 (ja) | 2010-04-09 | 2011-02-23 | 光源モジュール、およびそれを備えた電子機器 |
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WO2011126123A1 true WO2011126123A1 (ja) | 2011-10-13 |
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PCT/JP2011/058945 WO2011126123A1 (ja) | 2010-04-09 | 2011-04-08 | 光源モジュール、およびそれを備えた電子機器 |
Country Status (5)
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US (1) | US20120275188A1 (ja) |
EP (1) | EP2557354A1 (ja) |
JP (1) | JP5068865B2 (ja) |
CN (1) | CN102782395B (ja) |
WO (1) | WO2011126123A1 (ja) |
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KR101664507B1 (ko) * | 2011-12-08 | 2016-10-10 | 엘지이노텍 주식회사 | 표시장치 |
JP2016171423A (ja) * | 2015-03-12 | 2016-09-23 | キヤノン株式会社 | 画像読取装置 |
CN108027130B (zh) * | 2015-08-28 | 2021-08-10 | 科勒克斯有限责任公司 | 大面积光源和大面积照明器 |
US10830405B2 (en) | 2017-02-28 | 2020-11-10 | Coelux S.R.L. | Sunlight-based large area light source and large area luminaire |
CN110462286A (zh) | 2017-03-31 | 2019-11-15 | 3M创新有限公司 | 光导 |
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US20120275188A1 (en) | 2012-11-01 |
CN102782395A (zh) | 2012-11-14 |
JP5068865B2 (ja) | 2012-11-07 |
JP2011233508A (ja) | 2011-11-17 |
CN102782395B (zh) | 2015-01-28 |
EP2557354A1 (en) | 2013-02-13 |
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