KR101673547B1 - Back light unit and stereoscopic display apparatus having thereof - Google Patents

Back light unit and stereoscopic display apparatus having thereof Download PDF

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Publication number
KR101673547B1
KR101673547B1 KR1020150106032A KR20150106032A KR101673547B1 KR 101673547 B1 KR101673547 B1 KR 101673547B1 KR 1020150106032 A KR1020150106032 A KR 1020150106032A KR 20150106032 A KR20150106032 A KR 20150106032A KR 101673547 B1 KR101673547 B1 KR 101673547B1
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KR
South Korea
Prior art keywords
light
light source
guide plate
pixel
emitted
Prior art date
Application number
KR1020150106032A
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Korean (ko)
Inventor
이정민
이기욱
노형래
민지홍
Original Assignee
주식회사 엘엠에스
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    • 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
    • G02B27/22—
    • 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
    • G02B6/0026—Wavelength selective element, sheet or layer, e.g. filter or grating
    • G02F2001/133607—

Abstract

The present invention discloses a backlight unit and a stereoscopic display apparatus. The backlight unit includes: a light guide plate including a first light receiving surface, a second light receiving surface, a light emitting surface, and a bottom surface; a plurality of first light sources disposed along the first light receiving surface; and a plurality of second light sources disposed along the second light receiving surface. The light guide plate includes a plurality of diffraction gratings formed on the light emitting surface, and a light collecting pattern formed on the bottom surface.

Description

BACKLIGHT UNIT AND STEREOSCOPIC DISPLAY APPARATUS HAVING THEREOF BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

The present invention relates to a stereoscopic image display device capable of 2D-3D switching.

2. Description of the Related Art [0002] There has been active research on a stereoscopic image display device that converts a two-dimensional image formed on a display device into a three-dimensional image in accordance with recent technological advances.

In general, three-dimensional stereoscopic images are generally produced using the principle of binocular disparity through two eyes of a human being.

Since the two eyes of the human being are separated by a certain distance, the images observed from different angles with each eye are input to the brain, which enables the observer to perceive the sense of space by recognizing the three-dimensional feeling.

Among the methods of implementing such a three-dimensional image, a non-eyeglass type structure using a lenticular lens is configured to enable 2D-3D switching according to an electric field by injecting a driving liquid crystal after forming an orientation film in a negative lentic pattern.

However, in order to realize a three-dimensional image, a separate sub-panel or a plurality of optical sheets must be provided, which makes it difficult to reduce the thickness and increase the manufacturing cost.

The present invention provides a stereoscopic image display apparatus capable of reducing manufacturing cost and thinning by omitting a plurality of optical sheets.

A backlight unit according to one aspect of the present invention includes: a light guide plate including a first light incidence surface, a second light incidence surface, a light exiting surface, and a bottom surface; A plurality of first light sources disposed along the first light incidence surface; And a plurality of second light sources disposed along the second light incidence surface, wherein the light guiding plate includes a plurality of diffraction gratings formed on the light exiting surface, and a condensing pattern formed on the bottom surface.

The interval between the diffraction gratings may be smaller than a wavelength range of light emitted from the first light source and the second light source.

The interval between the diffraction gratings may be 200 nm to 600 nm.

The ratio of the width to the depth of the diffraction grating may be 1: 1.

The extending direction of the condensing pattern may intersect the extending direction of the diffraction grating.

According to an aspect of the present invention, a stereoscopic image display apparatus includes the backlight unit described above; And a main panel including a color filter that implements an image by light incident on the backlight, wherein the color filter includes a plurality of pixel portions, each pixel portion including a void pixel, a green pixel, and a red pixel can do.

The first light source and the second light source can emit light in the blue wavelength range.

The interval between the diffraction gratings may be smaller than a wavelength range of light emitted from the first light source and the second light source.

The interval between the diffraction gratings may be 200 nm to 600 nm.

The extending direction of the condensing pattern may intersect the extending direction of the diffraction grating.

According to the present invention, a stereoscopic image display apparatus capable of reducing manufacturing cost and thinning by omitting a plurality of optical sheets becomes possible.

1 is a conceptual diagram of a stereoscopic image display apparatus according to an embodiment of the present invention,
2 is a perspective view of a backlight unit according to an embodiment of the present invention,
3 is a conceptual view illustrating a process of emitting light emitted from a light source according to an embodiment of the present invention,
4 is an enlarged view of a diffraction grating according to an embodiment of the present invention,
5 is an enlarged view of a light converging pattern according to an embodiment of the present invention,
6 is a conceptual view of a liquid crystal panel according to an embodiment of the present invention,
7 is a conceptual diagram of a color filter according to an embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail.

It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

In the present invention, the terms "comprising" or "having ", and the like, specify that the presence of a feature, a number, a step, an operation, an element, a component, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

It is to be understood that the drawings are to be construed as illustrative and not restrictive.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the drawings, wherein like or corresponding elements are denoted by the same reference numerals, and redundant description thereof will be omitted.

1 is a conceptual diagram of a stereoscopic image display apparatus according to an embodiment of the present invention.

The stereoscopic image display apparatus according to the present invention mainly includes a liquid crystal panel 200 and a backlight unit 100 for supplying light to the liquid crystal panel 200.

In the backlight unit 100, the first light source 110 is disposed on one side of the light guide plate 130, and the second light source 120 is disposed on the other side. Accordingly, the light P1 emitted from the first light source 110 is guided by the light guide plate 130, refracted at a specific point in the direction of the liquid crystal panel 200, and incident on the observer's right or left eye.

The light P2 emitted from the second light source 120 is guided by the light guide plate 130 and refracted toward the main panel at a specific point so as to be incident on the observer's right eye or left eye. Therefore, the viewer feels a three-dimensional effect by the video signal inputted alternately. When the first light source 110 and the second light source 120 are simultaneously turned on / off, the observer perceives the planar image.

FIG. 2 is a perspective view of a backlight unit according to an embodiment of the present invention, FIG. 3 is a conceptual view illustrating a process of emitting light emitted from a light source according to an embodiment of the present invention, and FIG. 5 is an enlarged view of a light converging pattern according to an embodiment of the present invention.

Referring to FIG. 2, the backlight unit 100 includes a light guide plate 130, light sources 110 and 120 disposed on both sides of the light guide plate 130, and a reflection plate 140.

The light guide plate 130 includes a first light incidence surface 130a, a second light incidence surface 130b, a light exit surface 130c, and a bottom surface (not shown) on which light is incident. The first light incidence surface 130a and the second light incidence surface 130b are opposite to each other and are not limited to the long axis surface or the short axis surface of the light guide plate 130. [ The light exiting surface 130c may be a surface on which the light incident from the light source is emitted, and the bottom surface may be a surface facing the light exiting surface 130c.

A plurality of diffraction gratings 131 are disposed on the light exit surface 130c of the light guide plate 130. [ The diffraction grating 131 can control the outgoing angle of light. The diffraction grating 131 may be integrally formed by processing the light output surface 130c of the light guide plate 130, but is not limited thereto. For example, the diffraction grating 131 may be separately manufactured and attached to the light exiting surface 130c. The diffraction grating 131 may extend in a direction perpendicular to the direction in which the incident light advances. That is, the diffraction grating 131 may extend in the plane direction of the first light incidence surface 130a or the second light incidence surface 130b.

Referring to FIG. 3, the distance d1 between the diffraction gratings 131 may be 200 nm to 600 nm. Specifically, the distance d1 between the diffraction gratings 131 may be smaller than the wavelength of the light emitted from the light source. The interval and the shape of the diffraction grating 131 can be variously modified.

For example, when the wavelength of the light emitted from the light source is 450 nm, the interval d1 of the diffraction grating may be about 340 nm.

If the peak angle at which the light incident from the first light source 110 is emitted and the peak angle at which the light emitted from the second light source 120 is emitted satisfies 1 degree to 7 degrees, the interval and shape of the diffraction grating 131 And may not be particularly limited. As an example, the peak angle may be between 4 degrees and 6 degrees.

The peak angle can be defined as an angle formed by the normal V and the light L2 emitted from the light guide plate 130. [ The ratio of the width w1 to the depth d2 of the diffraction grating 131 may be 1: 1.

4, when the refractive index of the light guide plate 130 is about 1.50 and the refractive index of the air is 1.0, the light propagating toward the diffraction grating 131 of the light guide plate 130 has a difference in refractive index at the side face 131a of the diffraction grating Refracted. At this time, the ratio of the thickness of the light guide plate to the depth of the diffraction grating may be 150 or more and 3000 or less.

Referring to FIGS. 2 and 5, a light collecting pattern 132 is formed on the lower surface of the light guide plate 130. The light condensing pattern 132 may be formed in various shapes. For example, the light collecting pattern 132 may be formed in a semi-cylindrical shape.

The light condensing pattern 132 may extend to a lower portion of the light guide plate 130 and intersect the extending direction of the diffraction grating 131 described above. If the grating pattern and the light condensing pattern are crossed, various effects can be obtained. The condensing pattern 132 condenses and emits the diffused light, and thus can provide light of high luminance. At this time, the radius of curvature of the condensing pattern may be 1 to 50 mu m. If it is not satisfied, the peak angle to be emitted may not satisfy 1 to 7 degrees.

Further, when there is no condensing pattern, there is a problem that a viewing angle of light provided by the backlight is widened to cause crosstalk during generation of a stereoscopic image. However, according to the present invention, since the viewing angle is narrowed by the condensing pattern, can do.

In addition, the light collecting pattern 132 minimizes the contact surface with the reflective sheet 140 to minimize the occurrence of wet-out, and by forming the pattern on the lower side, the shielding force is increased to improve the appearance.

The condensing pattern 132 can increase the condensing effect as the vertical cross-sectional shape in the longitudinal direction is closer to hemispherical shape, and the pitch of the condensing pattern 132 can be formed within a range in which no moire occurs. The pitch of the condensing pattern 132 may be equal to or larger than the pitch of the diffraction grating.

The diffraction grating 131 formed on the upper surface of the light guide plate 130 and the light converging pattern 132 formed on the lower surface may be formed by a known pattern forming method. For example, a pattern may be formed using a stamp after the light guide plate 130 is manufactured, or a pattern may be formed on the mold to perform injection molding.

Referring to FIG. 2, the first light sources 110 are disposed along the first incident surface 130a of the light guide plate 130 in a plurality of directions. Accordingly, the light emitted from the first light source 110 is incident on the first incident surface 130a of the light guide plate 130 and proceeds toward the second incident surface 130b. At this time, most of the light is emitted to the outside at an angle of 1 degree to 7 degrees with respect to the normal line (V) by the condensing pattern 132 and the diffraction grating 131 during the progression toward the second incident surface 130b do.

Similar to the first light source 110, the second light sources 120 are disposed along the second incident surface 130b of the light guide plate 130 in a plurality of directions. Accordingly, the light emitted from the first light source 110 is incident on the second incident surface 130b of the light guide plate 130 and proceeds toward the first incident surface 130a. At this time, most of the light is emitted to the outside at an angle of 1 degree to 7 degrees with respect to the normal V by the condensing pattern 132 and the diffraction grating 131 during the progress toward the first incident surface.

The light provided by the backlight unit may be any one of blue, green, and red wavelength light instead of white light.

According to the present invention, it is possible to have a sufficient condensing effect even if a separate optical sheet is not further provided.

At this time, a controller (not shown) for supplying power to the first light source 110 and the second light source 120 may alternately supply power to the first light source 110 and the second light source 120 according to a predetermined period. For example, the first light source 110 and the second light source 120 can be turned on / off by switching at a cycle of 60 Hz. The period when the first light source 110 is turned on is synchronized with the period when the first image is outputted and the period when the second light source 120 is turned on is synchronized with the period during which the second image is outputted have.

If the first image is a video that is incident on the left eye of an observer and the second video is a video that is incident on an observer's right eye, the observer perceives perspective by binocular parallax. To this end, the control unit may include a timing circuit.

A reflection plate 140 may be formed under the light guide plate 130. The reflection plate 140 is disposed below the light condensing pattern 132 of the light guide plate 130 and reflects light passing through the light condensing pattern 132 of the light guide plate 130 toward the panel direction. 2, the reflector 140 may be integrally formed on the lower surface of the light guide plate 130. The reflector 140 may be integrally formed on the lower surface of the light guide plate 130. FIG.

FIG. 6 is a conceptual diagram of a liquid crystal panel according to an embodiment of the present invention, and FIG. 7 is a conceptual diagram of a color filter according to an embodiment of the present invention.

6, the liquid crystal panel 200 includes a TFT substrate 220, a color filter 230, and a liquid crystal layer 210 filled between the TFT substrate 220 and the color filter 230 .

The liquid crystal panel 200 may further include a polarizer 240 or 250 for adjusting the amount of light on the upper and lower surfaces of the liquid crystal panel 200. The liquid crystal panel 200 may change the alignment direction of the liquid crystal by controlling the voltage, It is possible to control the amount of light emitted through the light source.

Referring to FIG. 7, a plurality of RGB pixel portions 231 are formed in a region defined by a black matrix (not shown) on a substrate. Each pixel portion 231 includes a blue pixel 231a, a green pixel 231b, and a red pixel 231c.

At this time, the blue pixel 231a is composed of a void, and the incident light can transmit the light without changing the wavelength. When the first light source 110 and the second light source 120 are light of the blue wavelength range of 420 to 480 nm, the light of the blue wavelength range provided by the backlight unit can be used as it is, so that the fluorescent material corresponding to the blue pixel 231a is unnecessary. Therefore, there is an advantage that the manufacturing cost is reduced.

However, the present invention is not limited thereto, and the void pixel may be variously modified depending on the wavelength band of the light source. For example, if the light provided by the backlight unit is light in the red wavelength range, the red pixel may be a void pixel.

Green pixels and red pixels can be filled with quantum dots (QDs). The quantum dot has a size of about 2 to 15 nm and is composed of a core consisting of a core and ZnS (zinc sulfide). At least one of CdSe (cadmium selenide), CdTe (cadmium telluride), and CdS (cadmium sulfide) may be selected as the central body of the quantum dots.

These quantum dots generate strong fluorescence in a narrow wavelength range. The light emitted by the quantum dots is generated as electrons in an unstable (excited) state from a conduction band to a valence band.

Fluorescence generated at this time generates light with a shorter wavelength as the particles of the quantum dots become smaller, and light of longer wavelengths as the particles become larger.

Therefore, the wavelength band can be adjusted by disposing quantum dots capable of emitting light in the green wavelength band and light in the red wavelength band, respectively, in each pixel. At this time, since the quantum dots are susceptible to moisture, they can be formed in a film form or filled in a transparent tube.

100: Backlight unit
110: first light source
120: second light source
130: light guide plate
140: Reflector
200: liquid crystal panel
230: Color filter

Claims (11)

A light guide plate including a first light incidence surface, a second light incidence surface, a light exiting surface, and a bottom surface;
A plurality of first light sources disposed along the first light incidence surface; And
And a plurality of second light sources disposed along the second light incidence surface,
Wherein the light guide plate includes a plurality of diffraction gratings formed on a light emitting surface, and a light collecting pattern formed on the bottom surface,
Wherein a distance between the diffraction gratings is smaller than a wavelength range of light emitted from the first light source and the second light source,
A peak angle at which light incident from the first light source is emitted and a peak angle at which light incident from the second light source is emitted is 1 degree to 7 degrees and the peak angle is determined by the light emitted from the light guide plate and the thickness direction of the light guide plate, The angle formed by the parallel normal line,
Wherein the plurality of first light sources and the plurality of second light sources are alternately turned on / off.
delete The method according to claim 1,
And the interval between the diffraction gratings is 200 nm to 600 nm.
The method according to claim 1,
Wherein a ratio of a width to a depth of the diffraction grating is 1: 1.
The method according to claim 1,
And the extending direction of the condensing pattern crosses the extending direction of the diffraction grating.
A backlight unit according to claim 1;
And a main panel including a color filter that implements an image by light incident on the backlight,
Wherein the color filter includes a plurality of pixel portions, each pixel portion including a void pixel, a green pixel, and a red pixel.
The method according to claim 6,
Wherein the first light source and the second light source emit light of a blue wavelength band.
The method according to claim 6,
Wherein the light emitted from the first light source and the second light source has a wavelength before passing through the void pixel and the same wavelength after passing through the void pixel.
The method according to claim 6,
And the interval between the diffraction gratings is 200 nm to 600 nm.
The method according to claim 6,
Wherein the ratio of the width to the depth of the diffraction grating is 1: 1.
The method according to claim 6,
And the extending direction of the condensing pattern intersects the extending direction of the diffraction grating.
KR1020150106032A 2015-07-27 2015-07-27 Back light unit and stereoscopic display apparatus having thereof KR101673547B1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024032057A1 (en) * 2022-08-12 2024-02-15 华为技术有限公司 Three-dimensional display apparatus, three-dimensional display device and three-dimensional display method

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20120045603A (en) * 2010-10-29 2012-05-09 엘지디스플레이 주식회사 Backlgiht unit and liquid crystal display device the same
KR20150053656A (en) * 2013-11-08 2015-05-18 삼성디스플레이 주식회사 Backlight assembly and display apparatus having the same

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20120045603A (en) * 2010-10-29 2012-05-09 엘지디스플레이 주식회사 Backlgiht unit and liquid crystal display device the same
KR20150053656A (en) * 2013-11-08 2015-05-18 삼성디스플레이 주식회사 Backlight assembly and display apparatus having the same

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024032057A1 (en) * 2022-08-12 2024-02-15 华为技术有限公司 Three-dimensional display apparatus, three-dimensional display device and three-dimensional display method

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