CN100419530C - Area light source device and liquid crystal display - Google Patents
Area light source device and liquid crystal display Download PDFInfo
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- CN100419530C CN100419530C CNB2003101118055A CN200310111805A CN100419530C CN 100419530 C CN100419530 C CN 100419530C CN B2003101118055 A CNB2003101118055 A CN B2003101118055A CN 200310111805 A CN200310111805 A CN 200310111805A CN 100419530 C CN100419530 C CN 100419530C
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- grating
- light source
- guide plate
- light guide
- source device
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Abstract
The present invention relates to a surface light source device and a liquid crystal display. The surface light source device comprises a light guide plate, at least one light source and a plurality of diffraction grating units, wherein the light guide plate comprises a light emergent surface, a bottom surface which is opposite to the light emergent surface, and a light incident surface which is connected with the light emergent surface and the bottom surface; the light source is adjacent to the light incident surface; the diffraction grating units are arranged on the bottom surface of the light guide plate, and comprise two grating areas with different arrangement directions.
Description
[technical field]
The present invention relates to a kind of planar light source device and the LCD that adopts this planar light source device, particularly relate to a kind of planar light source device and LCD of bottom surface of light guide plate tool optical grating construction.
[background technology]
Planar light source device in the prior art LCD comprises light source and light guide plate, and light source is the incidence surface setting of relative light guide plate, and the transmission direction that this light-guide plate guides is sent light beam from light source converts line source or pointolite to the area source outgoing.A plurality of sites that distribute, the bottom surface of this light guide plate are in order to the light beam of dispersion light-guiding board internal transmission, to improve the homogeneity of light guide plate outgoing beam.For improving the not good problem of site outgoing light homogeneity, recently, the diffraction grating technology is used to light guide plate to improve the light guide plate outgoing light homogeneity.
A kind of planar light source device that adopts the diffraction grating technology can be consulted and announce in No. the 5th, 703,667, the United States Patent (USP) on Dec 30th, 1997.See also Fig. 1, this planar light source device 1 comprises that the reflecting plate 5, of fluorescent lamp 4, the one contiguous light guide plate 2 bottom surface 2b setting that a light guide plate 2, one contiguous light guide plate 2 incidence surface 2c are provided with is arranged at the diffuser plate 6 and the prism plate 7 of light guide plate 2 exiting surface 2a one side.This light guide plate 2 bottom surface 2b tools, one single arrangement and be parallel to the diffraction grating structure 3 of fluorescent lamp 4, this diffraction grating structure 3 make the light generation diffraction of incident on it, and a part of diffracted ray is from light guide plate 2 exiting surface 2a outgoing.Because from the light of fluorescent lamp 4 outgoing is white light, and because diffraction effect should can be split up into RGB three coloured light line outgoing substantially from the part diffracted ray of exiting surface 2a outgoing.RGB three coloured light lines are mixed into white again through diffuser plate 6 diffusions.Along change away from fluorescent lamp 4 directions grating 3 and non-grating region 3 in the unit length ' ratio, can improve this light guide plate 2 outgoing light homogeneity.But this patented technology exists not enough.
At first, these light guide plate 2 exiting surface 2a outgoing light homogeneity are still not enough.Reason is that the grating of this optical grating construction 3 is single arrangement architecture, and behind the incident ray generation diffraction, its diffracted ray can be arranged from exiting surface 2a outgoing perpendicular to this single grating.That is, this single grating is arranged feasible its direction of light from exiting surface 2a outgoing and mainly is in the plane of arranging perpendicular to this grating, and restriction light guide plate 2 light direction scopes are dwindled its angular field of view when making it to be applied to LCD.
Secondly, 2 bottom surface 2b are to light diffraction efficiency deficiency for this light guide plate, i.e. the non-grating region 3 of light guide plate 2 bottom surface 2b ' can the not make light generation diffraction of incident.For control bright dipping even, light guide plate 2 bottom surface 2b are all covered by optical grating construction 3, but exist non-grating region 3 ', but, this grating region 3 ' can not make light from exiting surface 2a outgoing, therefore, its corresponding exiting surface 2a part is dark than the exiting surface 2a part of optical grating construction 3 correspondences.
[summary of the invention]
In order to overcome the uneven defective of prior art planar light source device bright dipping, the invention provides the high planar light source device of a kind of outgoing light homogeneity.
The present invention also provides a kind of higher LCD of optical property that adopts above-mentioned planar light source device.
The technical scheme that technical solution problem of the present invention is adopted is: a kind of planar light source device is provided, it comprises a light guide plate, at least one light source and a plurality of diffraction grating unit, this light guide plate comprises an exiting surface, one and this exiting surface bottom surface and at least one incidence surface that joins with this exiting surface and this bottom surface that are oppositely arranged, contiguous this incidence surface of this at least one light source is provided with, this a plurality of diffraction grating unit is arranged at this bottom surface of light guide plate, it comprises two kinds of grating regions that orientation is different, this adjacent setting in diffraction grating unit and cover whole bottom surface of light guide plate.
The present invention provides a kind of LCD simultaneously, and this LCD comprises a liquid crystal panel and an above-mentioned planar light source device, and this liquid crystal panel is arranged at this light guide plate exiting surface one side.
Compare with prior art, the present invention has the following advantages: a plurality of diffraction grating unit of the bottom surface of light guide plate of planar light source device of the present invention is owing to have two kinds of different grating regions of orientation, these two kinds of grating regions can make the incident light generation diffraction of different directions, the different luminous flat in these two kinds of diffracted ray offices, thus improve this light guide plate and adopt the outgoing light homogeneity of the planar light source device of this light guide plate.LCD of the present invention is owing to adopting this planar light source device, so its angular field of view is bigger.
[description of drawings]
Fig. 1 is a kind of synoptic diagram of prior art planar light source device.
Fig. 2 is the synoptic diagram of planar light source device of the present invention.
Fig. 3 is the light guide plate sectional view and the light path synoptic diagram of planar light source device of the present invention.
Fig. 4 is the bright dipping synoptic diagram of planar light source device of the present invention.
[embodiment]
See also Fig. 2 and Fig. 3, planar light source device 30 of the present invention comprises a light guide plate 31 and a light source 32.This light guide plate 31 comprises an exiting surface 313, one and the bottom surface 312, that is oppositely arranged of this exiting surface 313 and this exiting surface 313 and this bottom surface 312 incidence surface 311 and a plurality of flank side surface 314 that join.This light source 32 is a line source such as CCFL (Cold CathodeFluorecent Lamp, cold cathode fluorescent lamp), certainly, also can be some light sources such as LED (Light Emitting Diode, light emitting diode), its contiguous these light guide plate 31 incidence surfaces 311 are provided with.In addition, this planar light source device 30 also comprises the reflecting plate (figure does not show) that contiguous these light guide plate 31 bottom surfaces 312 are provided with.
The light that this incidence surface 311 receives from light source 32, and it is imported in this light guide plate 31.This exiting surface 313 is derived this light guide plate 31 with light.This flank side surface 314 is a reflecting surface, its with incident on it light reflected back light guide plate 31 and via these exiting surface 313 outgoing.
This light guide plate 31 bottom surfaces 312 are provided with and light guide plate 31 integrated a plurality of diffraction grating unit 33, its adjacent setting and cover whole light guide plate 31 bottom surfaces 312.Each diffraction grating unit 33 comprises two kinds of grating region A and the B that the grating orientation is different, and the grating section of this diffraction grating unit 33 is a rectangle, and its grating constant P is 2～10 μ m, preferably 3 μ m; Corresponding rectangle width W is 1～5 μ m, preferably 1.5 μ m.
See also regional enlarged drawing I and the II of Fig. 2, A that this is arranged side by side and the mutual homeotropic alignment of its grating of B grating region, the grating of A grating region is arranged and is parallel to the light guide plate incidence surface, and the ratio of area that the A grating region accounts for whole diffraction grating unit 33 is big more away from light source 32 more.These diffraction grating unit 33 effects are to make light L that diffraction take place, and make light guide plate 31 exiting surfaces 313 luminous even.
This light guide plate 31 is with transparent material, makes as acryl resin, polycarbonate, polyvinyl resin or glass etc., and its refractive index is greater than 1, as 1.54.Because light guide plate 31 refractive indexes are greater than 1, after entering light guide plate 31 perpendicular to the light L of incidence surface 311, when the angle of incidence of light that incides diffraction grating unit 33 during greater than the angle of total reflection, because of the B grating region of diffraction grating unit 33 is parallel to light L, so the light L that incides the B grating region is by bottom surface 312 total reflections, in exiting surface 313 total reflection takes place subsequently equally, thus can be from 313 outgoing of light guide plate 31 exiting surfaces; And light L vertical incidence is during to the A grating region, arranges vertically with incident light L because of the grating of A grating region, and light L is in plane (first plane) the generation diffraction perpendicular to the orientation of A grating region grating.The light L that diffraction progression is lower
1Its incident angle θ that incides exiting surface 313 is less than the angle of total reflection, so it is from exiting surface 313 outgoing, and the higher light L of diffraction progression
2With L
3Wait its incident angle that incides exiting surface 313 greater than the angle of total reflection, propagate, until diffraction takes place next time and from exiting surface 313 outgoing so it is continued at by exiting surface 313 total reflections in the light guide plate 31.
The light L that diffraction progression is lower
1Account for the most energy of light L, it is from the light tool certain orientation of light guide plate 31 exiting surfaces 313 outgoing, and the grating parameter of control B grating region, as grating constant P, and the diffraction efficiency of may command light L.So there are better light utilization and light direction in diffraction grating unit 33 than the prior art lattice point structure, and the resolution of diffraction grating unit 33 is higher, adopts light guide plate 31 outgoing light homogeneity of this technology higher.
Equally, the B grating region also makes the incident ray perpendicular to its orientation in the plane (second plane) perpendicular to the orientation of B grating region grating diffraction take place, and a part of diffracted ray can be from exiting surface 313 outgoing.See also Fig. 4, different luminous flat (first and second plane, diffracted ray office that A and B grating region produce, promptly be respectively X-axis and Z plane that axle defines and Y-axis and Z plane that axle defines), so from the light intensity of light guide plate 31 exiting surfaces 313 all directions outgoing than balance, be that light guide plate 31 outgoing light homogeneity are higher, and light guide plate 31 bottom surfaces 312 are covered by continuous diffraction grating unit 33, so improve light utilization.In addition, for cooperating since light guide plate 31 each several parts apart from the light source 32 far and near different or limited situations that cause bottom surface 312 reception light inequalities of light source 32 lighting angles, the ratio of area that the A grating region accounts for whole diffraction grating unit 33 is big more away from light source 32 more, or the area ratio of light guide plate 31 bottom surfaces 312 at corresponding light source 32 two ends is bigger, so that the bright dipping ability of the exiting surface 313 of corresponding A grating region is inversely proportional to the light intensity that is incident to the A grating region, further improve light guide plate 31 outgoing light homogeneity.So planar light source device 30 of the present invention has better outgoing light homogeneity and light utilization than prior art.
In addition, also can change the grating constant P of each diffraction grating unit 33, thereby the diffraction efficiency that changes each diffraction grating unit 33 makes it more little away from light source 32 more to reach the purpose of even bright dipping as changing grating constant.
According to the present invention, this diffraction grating unit 33 can also be shown in the regional enlarged drawing III and IV of Fig. 2, and its grating slope is in light guide plate 31 incidence surfaces 311, and A is nested setting with the B grating region.For the situation of grating slope in light guide plate 31 incidence surfaces 311, scalable A and B grating region grating slope angle, the grating that A and B grating region be set are non-perpendicular arrangement and design A and the area ratio of B grating region, and diffraction grating unit 33 is inversely proportional to the area ratio of other parts and the intensity of incident ray L perpendicular to the part of light L incident.According to the present invention, also can with this a plurality of diffraction grating unit 33 separately make it be distributed in light guide plate 31 bottom surfaces 312 according to certain rules; The grating section of this diffraction grating unit 33 also can be arc or V-arrangement, and its grating constant is 2～10 μ m; These light guide plate 31 incidence surfaces 311 can be for a plurality of, and promptly flank side surface 314 also can be incidence surface 311, and a plurality of light sources 32 are provided with corresponding to these a plurality of incidence surfaces 311.
This a plurality of diffraction grating unit 33 is to adopt die casting technology and this light guide plate 31 one-body molded, the making employing electron beam lithography or the employing nanometer processing procedure of the pattern on the die surface that it is corresponding with diffraction grating unit 33.This diffraction grating unit 33 also can adopt printing process to be printed in this light guide plate 31 bottom surfaces 312, or adopt an optical thin film with a plurality of diffraction grating unit 33 structures to be attached at this light guide plate 31 bottom surfaces 312 except that aforesaid and light guide plate 31 are one-body molded.
The present invention also provides a LCD (figure does not show), and it comprises a liquid crystal panel and aforesaid planar light source device 30, and this liquid crystal panel is arranged at this light guide plate 31 exiting surfaces 313 1 sides.
Claims (12)
1. planar light source device, it comprises a light guide plate, at least one light source and a plurality of diffraction grating unit, this light guide plate comprises an exiting surface, one and the incidence surface that joins with this exiting surface and this bottom surface of the bottom surface that is oppositely arranged of this exiting surface and, contiguous this incidence surface of this at least one light source is provided with, this a plurality of diffraction grating unit is arranged at this bottom surface of light guide plate, it is characterized in that: this diffraction grating unit comprises two kinds of grating regions that orientation is different, this adjacent setting in diffraction grating unit and cover whole bottom surface of light guide plate.
2. planar light source device as claimed in claim 1 is characterized in that: the mutual homeotropic alignment of the grating of these two kinds of grating regions.
3. planar light source device as claimed in claim 2 is characterized in that: its grating of the grating region in these two kinds of grating regions is arranged and is parallel to the light guide plate incidence surface.
4. planar light source device as claimed in claim 3 is characterized in that: this area of grating region that is parallel to the light guide plate incidence surface is big more away from light source more.
5. planar light source device as claimed in claim 3 is characterized in that: this grating constant of grating region that is parallel to the light guide plate incidence surface is more little away from light source more.
6. planar light source device as claimed in claim 2 is characterized in that: the grating in these two kinds of grating regions is arranged and is favoured the light guide plate incidence surface.
7. planar light source device as claimed in claim 1 is characterized in that: these two kinds of grating regions are inversely proportional to perpendicular to the part of light incident area ratio and the intensity of incident light with other parts.
8. planar light source device as claimed in claim 1 is characterized in that: this a plurality of diffraction grating unit is one-body molded or adopt printing process to be printed in this bottom surface of light guide plate or be that an optical thin film is attached at this bottom surface of light guide plate with this light guide plate.
9. planar light source device as claimed in claim 1 is characterized in that: two kinds of grating regions in this diffraction grating unit are for being set up in parallel or nested setting.
10. planar light source device as claimed in claim 1 is characterized in that: the grating section of this diffraction grating unit is rectangle or arc, and its grating constant is 2～10 μ m, and section is that the rectangle width of the grating of rectangle is 1～5 μ m.
11. planar light source device as claimed in claim 1 is characterized in that: the grating section of this diffraction grating unit is rectangle or arc, and its grating constant is 3 μ m, and section is that the rectangle width of the grating of rectangle is 1.5 μ m.
12. a LCD, it comprises a liquid crystal panel, it is characterized in that: this LCD at least also comprises one as each described planar light source device in the claim 1 to 8, and this liquid crystal panel is arranged at this light guide plate exiting surface one side.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2003101118055A CN100419530C (en) | 2003-10-11 | 2003-10-11 | Area light source device and liquid crystal display |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2003101118055A CN100419530C (en) | 2003-10-11 | 2003-10-11 | Area light source device and liquid crystal display |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1605913A CN1605913A (en) | 2005-04-13 |
| CN100419530C true CN100419530C (en) | 2008-09-17 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2003101118055A Expired - Fee Related CN100419530C (en) | 2003-10-11 | 2003-10-11 | Area light source device and liquid crystal display |
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| Country | Link |
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| CN (1) | CN100419530C (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102009027288A1 (en) * | 2009-06-29 | 2010-12-30 | Evonik Röhm Gmbh | Light guide plate with embedded light-scattering impurities and method for its production |
| TWI476483B (en) * | 2011-03-31 | 2015-03-11 | Chi Mei Materials Technology Corp | Display apparatus and a liquid crystal display device |
| TWI477823B (en) * | 2012-05-28 | 2015-03-21 | E Ink Holdings Inc | Light guide and electrophoretic display apparatus switchable between black-white mode and color mode |
| CN103454714B (en) | 2012-05-28 | 2016-08-24 | 元太科技工业股份有限公司 | Light guide plate and electrophoretic display device capable of switching between color mode and black-and-white mode |
| CN113934056B (en) * | 2021-10-28 | 2023-10-10 | 京东方科技集团股份有限公司 | Light source assembly, display device and surface light source device |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08297204A (en) * | 1995-04-26 | 1996-11-12 | Dainippon Printing Co Ltd | Color filter and color liquid crystal display device |
| JPH10332916A (en) * | 1997-05-30 | 1998-12-18 | Toppan Printing Co Ltd | Diffraction grating pattern |
| JP2000266914A (en) * | 1999-03-12 | 2000-09-29 | Toppan Printing Co Ltd | Light diffuser and display device using it |
| JP2001183529A (en) * | 1999-12-22 | 2001-07-06 | Victor Co Of Japan Ltd | Master hologram |
| CN1352786A (en) * | 1999-05-28 | 2002-06-05 | 智能控制系统有限公司 | Light indicator |
| JP2003045217A (en) * | 2001-08-03 | 2003-02-14 | West Electric Co Ltd | Illumination device |
-
2003
- 2003-10-11 CN CNB2003101118055A patent/CN100419530C/en not_active Expired - Fee Related
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08297204A (en) * | 1995-04-26 | 1996-11-12 | Dainippon Printing Co Ltd | Color filter and color liquid crystal display device |
| JPH10332916A (en) * | 1997-05-30 | 1998-12-18 | Toppan Printing Co Ltd | Diffraction grating pattern |
| JP2000266914A (en) * | 1999-03-12 | 2000-09-29 | Toppan Printing Co Ltd | Light diffuser and display device using it |
| CN1352786A (en) * | 1999-05-28 | 2002-06-05 | 智能控制系统有限公司 | Light indicator |
| JP2001183529A (en) * | 1999-12-22 | 2001-07-06 | Victor Co Of Japan Ltd | Master hologram |
| JP2003045217A (en) * | 2001-08-03 | 2003-02-14 | West Electric Co Ltd | Illumination device |
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| Publication number | Publication date |
|---|---|
| CN1605913A (en) | 2005-04-13 |
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Granted publication date: 20080917 Termination date: 20171011 |