CN100370338C - Back light system - Google Patents
Back light system Download PDFInfo
- Publication number
- CN100370338C CN100370338C CNB031400868A CN03140086A CN100370338C CN 100370338 C CN100370338 C CN 100370338C CN B031400868 A CNB031400868 A CN B031400868A CN 03140086 A CN03140086 A CN 03140086A CN 100370338 C CN100370338 C CN 100370338C
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- Prior art keywords
- light
- guide plate
- back light
- light system
- crystal
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Abstract
The present invention discloses a back light system which comprises a light guide plate, a plurality of point light sources, and a birefringent crystal group, wherein the light guide plate comprises an incident surface, a light emergent surface which is connected with the incident surface, and a bottom surface which is opposite to the light emergent surface; the point light sources are arranged correspondingly to the incident surface; the birefringent crystal group is arranged between the light guide plate and the point light sources. Light beams emitted by the point light sources pass through the birefringent crystal group, and enter the light guide plate. The back light system has high light emergent uniformity.
Description
[technical field]
The present invention relates to a kind of back light system, refer to a kind of back light system that adopts pointolite especially.
[background technology]
Because advantages such as LCD has gently, approaches, power consumption is little are widely used in modernized information equipments such as notebook computer, mobile phone, personal digital assistant.Because the liquid crystal in the LCD itself is not had a characteristics of luminescence, need provide back light system to realize Presentation Function for it.
The prior art back light system comprises light source and light guide plate, the plane of incidence setting of the relative light guide plate of light source, and this light-guide plate guides light source sends the transmission direction of light beam, converts line source or pointolite to the area source outgoing.A plurality of sites that distribute, the bottom surface of this light guide plate in order to the total reflection condition of broken beam in the light guide plate internal transmission, and make its scattering improving the homogeneity of light guide plate outgoing beam, and then promote the overall performance of back light system.The density of this site, size all can have different designs to adapt to different back light systems.
As everyone knows, the outgoing light homogeneity of back light system will reach predetermined demand, thereby promotes the visible angle of color contrast, full frame regional luminance effect and the complete machine of LCD.
A kind of prior art back light system can be consulted Fig. 1.This back light system 20 comprises a plurality of light emitting diodes 21 and light guide plate 22, this light guide plate 22 is tabulars, comprise the exiting surface 222 that the plane of incidence 221 and the plane of incidence 221 intersect, bottom surface 223 and a plurality of side 224 of relative exiting surface 222, this bottom surface 223 has a plurality of scattering units 23, and these light emitting diode 21 corresponding planes of incidence 221 are provided with.This plane of incidence 221 receives the light beam that light emitting diodes 21 send, and the plane of incidence 221 caves inward over against the surface of light emitting diode 21 respectively and be curved surface, so that fixedly light emitting diode 21 also and its light path good coupling.This exiting surface 222 can be processed as the uneven surface with certain roughness, so that the distribution of the light beam briliancy of outgoing is more even.
Seeing also Fig. 2, is the optical field distribution figure of light emitting diode 21.The light distribution of light emitting diode 21 is normally rotational symmetric, and its exiting surface intensity descends fast with the increase of angle, and the light distribution of horizontal direction and vertical direction all has this specific character.
Please in the lump with reference to the light intensity curve 25 of light emitting diode 21 shown in Figure 3, its light intensity is concentrated and is distributed in certain spread angle range, and the distribution of this scope light intensity also increases with angle and descends, the emergent light that is light emitting diode 21 distributes very inhomogeneous, therefore enter light guide plate 22 and after light guide plate 22 transmission outgoing light homogeneity be difficult to reach pre-provisioning request, and easily cause bigger incident dark space.
[summary of the invention]
In order to overcome the low defective of prior art back light system outgoing light homogeneity, the invention provides the high back light system of a kind of outgoing light homogeneity.
The technical scheme of technical solution problem of the present invention is: a kind of back light system is provided, comprise light guide plate, a plurality of pointolite and birefringece crystal group, this light guide plate comprises the exiting surface that the plane of incidence links to each other with the plane of incidence and the bottom surface of relative exiting surface, these a plurality of pointolites this plane of incidence relatively are provided with, and this birefringece crystal group is between light guide plate and pointolite.
Backlight arrangement of the present invention further improves and is: the number of described birefringece crystal group and the number of pointolite equate.
Wherein, this birefringece crystal group comprises two birefringent wedge crystal.
Wherein, the shape of described two birefringent wedge crystal is identical.
Wherein, this birefringent wedge crystal is a lithium columbate crystal.
Wherein, this birefringent wedge crystal is a yttrium vanadate crystal.
Wherein, described birefringece crystal group is a parallelepipedon, its two side faces parallelogram.
Wherein, described pointolite is a light emitting diode.
Wherein, this bottom surface is coated with reflectance coating.
Compare prior art, the invention has the beneficial effects as follows: because back light system of the present invention adopts the birefringece crystal group that is arranged between pointolite and the light guide plate, the light beam that pointolite sends is stack again after this birefringece crystal component is opened, reenter the plane of incidence that is incident upon light guide plate, thereby obtain the optical field distribution of a distribution uniform, increase the back light system outgoing light homogeneity with this.
[description of drawings]
Fig. 1 is a kind of three-dimensional exploded view of prior art back light system.
Fig. 2 is the optical field distribution figure of light emitting diode shown in Figure 1.
Fig. 3 is the another kind of optical field distribution figure of light emitting diode shown in Figure 1.
Fig. 4 is the stereographic map of back light system first embodiment of the present invention.
Fig. 5 is the stereographic map of birefringece crystal shown in Figure 4.
Fig. 6 is the optical axis synoptic diagram of birefringece crystal shown in Figure 4.
Fig. 7 to Fig. 9 is the light path principle figure of birefringece crystal shown in Figure 4.
Figure 10 is the angular distribution figure of light beam from birefringece crystal group output shown in Figure 4.
Figure 11 is that light beam enters light guide plate time field pattern.
Figure 12 is the stereographic map of back light system second embodiment of the present invention.
[embodiment]
Seeing also Fig. 4, is back light system first embodiment of the present invention, and this back light system 100 comprises a plurality of pointolites 110, a plurality of birefringece crystal group 120 and a light guide plate 130.This pointolite 110 sends light beam, overlaps after the light beam generation birefringence that these a plurality of birefringece crystal groups 120 are sent this pointolite 110, and the transmission direction of 130 lead beams of this light guide plate is converted into the area source outgoing.
In the present embodiment, this pointolite 110 can be a light emitting diode, and light emitting diode that can be by disposing a plurality of different colours is to allocate required light source colour and briliancy.Certainly, the similar pointolite of the optical field distribution of other emergent light and light emitting diode all can be used.
This light guide plate 130 is plate shaped light guide plate, adopts transparent materials such as acryl, glass or polycarbonate to make, it comprise exiting surface 132 that a plane of incidence 131 links to each other with the plane of incidence 131 and with exiting surface 132 opposed bottom surface 133.These plane of incidence 131 acceptance point light sources 110 send and through the light beam of birefringece crystal group 120 transmission.This exiting surface 132 can be processed as the uneven surface of tool certain roughness.The bottom surface 133 of light guide plate 130 is provided with a plurality of sites 134, and this site 134 can be distributed in the bottom surface 133 of light guide plate 130 by modes such as printing or ejection formations, and it is a spherical shape.Certainly, for improving the briliancy and the homogeneity of light guide plate 130 outgoing beams, the size of this site 134 also can increase progressively along the direction away from the plane of incidence 131.This site 134 also can be cylindric, square, pyramid or other suitable shape.In addition, also can be 133 a plurality of V-type grooves (figure does not show) be set to substitute these a plurality of sites 134 in the bottom surface.
Please in the lump with reference to figure 5 to Fig. 6, this birefringece crystal group 120 is parallelepipedons, its two sides parallelogram.It comprises the birefringent wedge crystal 121 and 122 that two shapes are identical, and this birefringece crystal 121 and 122 can be a yttrium vanadate crystal.This birefringece crystal 121 comprises first surface 1211 and second surface 1212, and the angle of its optical axis A and Z-axis is 45 degree, and lies low on the MNOP of plane.The angle of the optical axis B of this birefringece crystal 122 and the optical axis A of birefringece crystal 121 is 90 degree.
Please one opening with reference to figure 7 to Fig. 9, is the part index path of this back light system 100.This birefringece crystal 121 and 122 wedge angle are θ
ω, from a branch of light of pointolite 110 with θ
ωBe incident to first surface 1211, because the characteristic of birefringece crystal, this light beam is split up into ordinary light o light and extraordinary ray e light, is that example illustrates its light path traveling process with o light.
With reference to figure 7, light beam reflects at first surface 1211 places, can know according to refraction law: sin θ
ω=n
oSin θ
O1, wherein, n
oRepresent the refractive index of o light.And θ
O2=θ
ω-θ
O1
With reference to figure 8,,, promptly have: n at first surface 1221 places of birefringece crystal 122 so when light beam enters into birefringece crystal 122, the situation that refractive index is exchanged takes place because the angle of the optical axis A of the optical axis B of birefringece crystal 122 and birefringece crystal 121 is 90 degree
oSin θ
O2=n
eSin θ
O1, wherein, n
eRepresent the refractive index of o light in birefringece crystal 122.
With reference to figure 9, light beam when second surface 1222 outgoing of birefringece crystal 122, θ
O4=θ
ω-θ
O3According to refraction law, have: n
eSin θ
O4=sin θ
O5So the incident light of a branch of parallel, horizontal axle is after the effect of birefringece crystal group, during the outgoing of o light and the angle theta of transverse axis
O6=θ
ω-θ
O5
The above is the index path of o light, and is same, and e light is through birefringece crystal group 120 refraction backs and the angled outgoing of transverse axis.Please refer to Figure 10, wherein horizontal ordinate is represented the wedge angle of birefringece crystal 121 and 122, and ordinate is represented the angle of o light and e light and horizontal direction.
Please refer to Figure 11, the light beam that pointolite 110 sends is split up into the two light beams outgoing after 120 effects of birefringece crystal group, and wherein the light intensity curve of this two light beams is respectively 141 and 142, and the light intensity curve after the two overlaps is shown in 143.Promptly utilize this birefringece crystal group 120, can be so that the optical field distribution of the light beam that pointolite 110 sends be comparatively even, thus promote the outgoing light homogeneity of back light system 100.
Certainly, this two-fold crystal group 120 also can adopt lithium columbate crystal, and the birefringence effect of birefringece crystal is bigger, and the light field that is produced changes bigger.
Seeing also Figure 12, is back light system second embodiment of the present invention.This back light system 300 comprises a plurality of pointolites 310, two birefringece crystal groups 320 and a light guide plate 330.
This light guide plate 330 is plate shaped light guide plate, and it comprises bottom surfaces 333 that two planes of incidence 331, vertically link to each other with the plane of incidence 331 and an exiting surface 332 relative with bottom surface 333.Certainly this light guide plate 330 also can be sought tabula rasa for wedge shape.This bottom surface 333 has a plurality of equally distributed sites 334 to improve the whole optical property of back light system 300.Certainly, this bottom surface 333 also can be provided with vaporific flower or the texture (figure do not show) of picking to substitute these a plurality of sites 334.These bottom surface 333 plating reflectance coatings (figure do not show) are with reflection projection light beam thereon, also can reflecting plate (figure does not show) be set in contiguous these bottom surface 333 1 sides and 333 overflow from the bottom surface to prevent light beam, thereby increase the bright dipping briliancy of back light system 300.
310 pairs of this pointolites should be laid by two planes of incidence 331, this two birefringece crystals group 320 is between pointolite 310 and light guide plate 330, overlap after the light beam generation birefringence that this pointolite 310 is sent, the transmission direction of 330 lead beams of this light guide plate is converted into the area source outgoing.
Claims (10)
1. back light system, comprise light guide plate and pointolite, this light guide plate comprises the exiting surface that the plane of incidence links to each other with the plane of incidence and the bottom surface of exiting surface relatively, this pointolite is arranged near the plane of incidence place of this light guide plate and towards the plane of incidence of this light guide plate, it is characterized in that: this back light system also comprises the birefringece crystal group between light guide plate and pointolite.
2. back light system as claimed in claim 1 is characterized in that: the number of described birefringece crystal group and the number of pointolite equate.
3. back light system as claimed in claim 2 is characterized in that: each birefringece crystal group includes two birefringent wedge crystal.
4. back light system as claimed in claim 3 is characterized in that: the shape of described two birefringent wedge crystal is identical.
5. back light system as claimed in claim 3 is characterized in that: this birefringent wedge crystal is a lithium columbate crystal.
6. back light system as claimed in claim 3 is characterized in that: this birefringent wedge crystal is a yttrium vanadate crystal.
7. back light system as claimed in claim 1 is characterized in that: described birefringece crystal group comprises two birefringent wedge crystal.
8. back light system as claimed in claim 1 is characterized in that: described birefringece crystal group is a parallelepipedon.
9. back light system as claimed in claim 1 is characterized in that: described pointolite is a light emitting diode.
10. back light system as claimed in claim 1 is characterized in that: this bottom surface is coated with reflectance coating.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB031400868A CN100370338C (en) | 2003-08-03 | 2003-08-03 | Back light system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB031400868A CN100370338C (en) | 2003-08-03 | 2003-08-03 | Back light system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1580897A CN1580897A (en) | 2005-02-16 |
| CN100370338C true CN100370338C (en) | 2008-02-20 |
Family
ID=34579229
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB031400868A Expired - Fee Related CN100370338C (en) | 2003-08-03 | 2003-08-03 | Back light system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN100370338C (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9223080B2 (en) * | 2012-04-24 | 2015-12-29 | Qualcomm Mems Technologies, Inc. | Light guide with narrow angle light output and methods |
| CN110095904A (en) * | 2019-05-27 | 2019-08-06 | 惠州市华星光电技术有限公司 | Down straight aphototropism mode set and liquid crystal display device |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0992886A (en) * | 1995-09-26 | 1997-04-04 | Nichia Chem Ind Ltd | Led surface light source |
| CN1195120A (en) * | 1997-03-28 | 1998-10-07 | 夏普株式会社 | Front illumination device and reflection-type liquid crystal display device incorporating same |
| JP2000222924A (en) * | 1999-01-28 | 2000-08-11 | Hitachi Chem Co Ltd | Surface light source element having narrow angle of visibility |
| JP2002237211A (en) * | 2001-02-08 | 2002-08-23 | Nitto Denko Corp | Polarization plane light source and liquid crystal display provided with the same |
| US6497492B1 (en) * | 1997-10-03 | 2002-12-24 | Thomson Licensing Sa | Back-lighting system for a transmissive electrooptic modulator using the light polarization effect |
| JP2002373519A (en) * | 2001-06-18 | 2002-12-26 | Fujitsu Ltd | Illumination equipment and liquid crystal display equipment |
| JP2003172932A (en) * | 2001-09-28 | 2003-06-20 | Seiko Epson Corp | Liquid crystal display device and electronic appliance |
-
2003
- 2003-08-03 CN CNB031400868A patent/CN100370338C/en not_active Expired - Fee Related
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0992886A (en) * | 1995-09-26 | 1997-04-04 | Nichia Chem Ind Ltd | Led surface light source |
| CN1195120A (en) * | 1997-03-28 | 1998-10-07 | 夏普株式会社 | Front illumination device and reflection-type liquid crystal display device incorporating same |
| US6497492B1 (en) * | 1997-10-03 | 2002-12-24 | Thomson Licensing Sa | Back-lighting system for a transmissive electrooptic modulator using the light polarization effect |
| JP2000222924A (en) * | 1999-01-28 | 2000-08-11 | Hitachi Chem Co Ltd | Surface light source element having narrow angle of visibility |
| JP2002237211A (en) * | 2001-02-08 | 2002-08-23 | Nitto Denko Corp | Polarization plane light source and liquid crystal display provided with the same |
| JP2002373519A (en) * | 2001-06-18 | 2002-12-26 | Fujitsu Ltd | Illumination equipment and liquid crystal display equipment |
| JP2003172932A (en) * | 2001-09-28 | 2003-06-20 | Seiko Epson Corp | Liquid crystal display device and electronic appliance |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1580897A (en) | 2005-02-16 |
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| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
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Granted publication date: 20080220 Termination date: 20170803 |