CN110888256A - Polarization conversion optical system for improving LED backlight illumination efficiency - Google Patents
Polarization conversion optical system for improving LED backlight illumination efficiency Download PDFInfo
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- CN110888256A CN110888256A CN201911158640.4A CN201911158640A CN110888256A CN 110888256 A CN110888256 A CN 110888256A CN 201911158640 A CN201911158640 A CN 201911158640A CN 110888256 A CN110888256 A CN 110888256A
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- prism
- gluing
- polarization
- optical system
- polarization conversion
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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
- G02F1/133528—Polarisers
Abstract
The invention discloses a polarization conversion optical system for improving the LED backlight illumination efficiency, which relates to the technical field of polarization conversion optical systems and comprises a collimating lens module and a polarization converter, wherein the polarization converter comprises a prism I to a prism VII, inclined planes of the prism I to the prism VII are glued into a whole through optical cement, and the prism V, the prism VI and the prism VII are symmetrically distributed relative to a prism IV, a prism III, a prism II and a prism I; the first gluing surface, the third gluing surface, the fourth gluing surface and the sixth gluing surface are plated with polarization beam splitting films; the first outer side face, the second bonding face, the fifth bonding face and the second outer side face are plated with total reflection metal films. The polarization conversion optical system for improving the LED backlight illumination efficiency can convert all emergent non-polarized light beams into polarized light in a single polarization state, can realize homogenization, does not need to be matched with a micro-lens array group, reduces the design size of a lens group, reduces the design difficulty of a light source part, and reduces the cost.
Description
Technical Field
The invention relates to a polarization conversion optical system, in particular to a polarization conversion optical system for improving the LED backlight illumination efficiency.
Background
LED backlight refers to the use of LEDs (light emitting diodes) as the backlight source of an LCD display for illuminating the LCD display. The existing backlight source mostly uses an LED as an illumination light source and adopts a direct illumination mode, the LED is an unpolarized light source, the LCD is a polarization device, only horizontal polarized light illuminates the LCD, and vertical polarized light is absorbed and lost, so that the system has low light energy utilization rate and low display brightness; and because the transmittance of the LCD is low, the absorption is large, and a large amount of vertical polarized light is absorbed, the LCD screen is damaged due to overhigh temperature rise.
In the prior art, a polarization conversion optical system for improving the direct type backlight illumination efficiency is mainly realized by adopting the following technical scheme:
the first technical scheme is as follows: as shown in fig. 1, after being collimated, the LED light source is a polarization conversion device made of two groups of micro-array lenses, a calcite crystal and a half-wave plate. In the structure, each small lens of the first micro array lens forms an image of a light source, the image is imaged on the corresponding second micro array lens, the second micro array lens images the image of the first micro array lens in the space behind the first micro array lens through superposition on an LCD screen, and therefore the purpose of light uniformization is achieved, wherein the unit lens of the first micro array lens is 2 times that of the unit lens of the second micro array lens, the first micro array lens and the second micro array lens are matched, and therefore parallel incident unpolarized light is divided into parallel light beams with equal width and equal intervals to be incident on calcite crystals. Due to the structural characteristics of the calcite crystal, the optical axis of the calcite crystal forms 45 degrees 23' with the cleavage plane, when unpolarized light enters from the vertical cleavage plane, the calcite crystal is divided into vertically polarized light and horizontally polarized light, the vibration direction of the vertically polarized light is vertical to the optical axis (also vertical incidence plane), the propagation direction of the horizontally polarized light forms a certain included angle with the optical axis, the vibration direction is vertical to the vibration direction of the vertically polarized light, the vertically polarized light and the horizontally polarized light are separated from each other on the exit plane of the calcite crystal and do not have an overlapped part, a half-wave plate is pasted on the exit area of the vertically polarized light, the main axis of the half-wave plate forms 45 degrees with the vibration direction of the vertically polarized light, so that after the vertically polarized light passes through the strip-shaped half-wave plate pasted on the crystal, the vibration direction of the vertically polarized light is rotated by 90 degrees and is consistent with the vibration direction of the, thus, linearly polarized light having a uniform polarization direction is obtained. The slit grating is used for blocking light leakage at the edges of the small lenses and preventing stray light from passing through the emergent region of the vertically polarized light so as to improve the extinction ratio of output light.
The defects of the technical scheme are as follows: the light from the light source can be effectively divided into two parts only by using the micro-array lens, and due to the influence of processing design and the parallelism of parallel light, the light emitted after being converted from the polarization converter is not necessarily mixed with unpolarized light or horizontal polarized light to influence the light efficiency, and the size of the collimating lens group is required to be the same as that of the polarization converter, so that the optical design is complex and the cost is high by adopting the scheme.
The second technical scheme is as follows: as shown in fig. 2 and 3, a plurality of prisms are linearly arranged and combined together, a half-wave plate is attached to every other prism on the emergent surface of the polarization converter, the incident surface of the polarization converter is divided into a transparent region and a non-transparent region to form interval arrangement, the structure adopts prism bonding, but the structure is matched with a micro-array lens to ensure that light beams can only be incident through the transparent region, so that light emitted by a light source can be fully used, and the non-polarized light incident into the polarization converter is completely converted into polarized light in the vertical direction.
The defects of the technical scheme are as follows: the light-transmitting and non-light-transmitting treatment needs to be carried out on the cemented prism, the micro-array lens group needs to be adopted and is a non-single lens array, the processing difficulty is high, non-polarized light or horizontal polarized light is mixed with light which is easy to be converted from the polarization converter, the light effect is influenced, the size of the collimating lens group needs to be the same as that of the polarization converter, and therefore the optical design is complex and the cost is high by adopting the scheme.
Disclosure of Invention
The invention aims to overcome the defects and provide a polarization conversion optical system for improving the LED backlight illumination efficiency, and solves the problems of complex optical design and high cost of the polarization conversion optical system in the prior art.
The technical scheme adopted by the invention is as follows:
a polarization conversion optical system for improving the LED backlight illumination efficiency comprises a collimating lens module and a polarization converter, wherein the polarization converter comprises a first prism, a second prism, a third prism, a fourth prism, a fifth prism, a sixth prism and a seventh prism, inclined planes of the first prism, the second prism, the third prism, the fourth prism, the fifth prism, the sixth prism and the seventh prism are glued into a whole through optical glue, the outer side surface of the first prism forms a first outer side surface, the outer side surface of the seventh prism forms a second outer side surface, the glued surfaces of the first prism and the second prism form a first glued surface, the glued surfaces of the second prism and the third prism form a second glued surface, the glued surfaces of the third prism and the fourth prism form a third glued surface, the glued surfaces of the fourth prism and the fifth prism form a fourth glued surface, and the glued surfaces of the fifth prism and the sixth prism form a fifth glued surface, the bonding surfaces of the sixth prism and the seventh prism form a sixth bonding surface, wherein,
the fourth prism is an equilateral right-angled triangle prism, and the first prism, the second prism, the third prism, the fifth prism, the sixth prism and the seventh prism are all parallelogram prisms with equal sizes;
the prism five, the prism six and the prism seven are symmetrically distributed with the prism three, the prism two and the prism one relative to the prism four;
half-wave plates are attached to the emergent surfaces of the first prism, the fourth prism and the seventh prism;
the first gluing surface, the third gluing surface, the fourth gluing surface and the sixth gluing surface are plated with polarization beam splitting films;
and the first outer side surface, the second bonding surface, the fifth bonding surface and the second outer side surface are plated with total reflection metal films.
Furthermore, the incidence surfaces of the second prism, the third prism, the fifth prism and the sixth prism are plated with AR antireflection films.
Furthermore, the emergent surfaces of the first prism, the second prism, the third prism, the fourth prism, the fifth prism, the sixth prism and the seventh prism are all plated with AR antireflection films.
Preferably, the polarization beam splitting film is made of MgF 2/ZnS.
Furthermore, the size of the incidence plane from the second prism to the sixth prism is the size of the light emitting source of the LED light source.
In the invention, the LED divergent light source is collimated after the LED light source passes through the collimating lens group, the size of the light emitting source is from the second prism to the six incident surfaces of the prism, the collimated light enters from the second prism, the third prism, the fifth prism and the six incident surfaces of the prism, the use efficiency can be improved due to the AR antireflection film, and the light is unpolarized light at the moment:
the unpolarized light is divided into horizontal polarized light and vertical polarized light through a third bonding surface, the horizontal polarized light is emitted from a fourth emergent surface of the prism through the third bonding surface, and is converted into vertical polarized light after passing through a half-wave plate, the vertical polarized light is reflected by the third bonding surface, and is still vertical polarized light after being emitted from a third emergent surface of the prism through total reflection of the second bonding surface;
the unpolarized light is totally reflected by the second gluing surface, after passing through the first gluing surface, the polarized light in the vertical direction is reflected by the first gluing surface and is still vertically polarized after being emitted through the second emergent surface of the prism, the polarized light in the horizontal direction is reflected by the first outer side surface after passing through the second gluing surface and is emitted through the first emergent surface of the prism, the surface is plated with an AR anti-reflection film, the transmission utilization rate can be enhanced, and at the moment, the polarized light in the vertical direction is converted into the polarized light in the vertical direction after passing through a half-wave plate.
Because the prism five, the prism six and the prism seven are symmetrically distributed relative to the prism four, the prism three and the prism two, the light direction and the polarization conversion principle are completely the same.
The invention has the beneficial effects that:
the polarization conversion optical system for improving the LED backlight illumination efficiency can convert all emergent non-polarized light beams into polarized light in a single polarization state, can realize homogenization, does not need to be matched with a micro-lens array group, reduces the design size of a lens group, reduces the design difficulty of a light source part, and reduces the cost;
the non-polarized light emitted by the LED in the backlight illumination system is converted into uniform polarized light in a single direction, so that the light energy utilization rate of an image source unit LCD in backlight illumination can be effectively improved, the temperature rise of the LCD can be reduced, and the front-end optical design size can be reduced.
The present invention is described in further detail below with reference to the attached drawing figures.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a first structural diagram of a polarization conversion optical system for improving the efficiency of direct-type backlight illumination in the prior art.
Fig. 2 is a schematic structural diagram of a polarization conversion optical system for improving the efficiency of direct-type backlight illumination in the prior art.
Fig. 3 is a schematic structural diagram of a polarization conversion optical system for improving the efficiency of direct-type backlight illumination in the prior art.
FIG. 4 is a schematic diagram of a polarization conversion optical system for improving the efficiency of LED backlight illumination according to the present invention.
In the figure, 1-collimating lens module 2-polarization converter
21-first prism 22-second prism 23-third prism 24-fourth prism 25-fifth prism 26-sixth prism 27-seventh prism 28-half-wave plate
201-first glue face 202-second glue face 203-third glue face 204-fourth glue face 205-fifth glue face 206-sixth glue face 207-first lateral face 208-second lateral face.
Detailed Description
For the purpose of enhancing an understanding of the present invention, the present invention will be described in further detail with reference to the accompanying drawings and examples. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.
As shown in fig. 4, the polarization conversion optical system for improving the efficiency of LED backlight according to the present invention includes a collimating lens module 1 and a polarization converter 2, the polarization converter includes a first prism 21, a second prism 22, a third prism 23, a fourth prism 24, a fifth prism 25, a sixth prism 26 and a seventh prism 27, the inclined surfaces of the first prism 21, the second prism 22, the third prism 23, the fourth prism 24, the fifth prism 25, the sixth prism 26 and the seventh prism 27 are bonded together by optical glue, the outer side surface of the first prism 21 forms a first outer side surface 207, the outer side surface of the seventh prism 27 forms a second outer side surface 208, the bonded surfaces of the first prism 21 and the second prism 22 form a first bonded surface 201, the bonded surfaces of the second prism 22 and the third prism 23 form a second bonded surface 202, the bonded surfaces of the third prism 23 and the fourth prism 24 form a third bonded surface 203, the bonded surfaces of the fourth prism 24 and the fifth prism 25 form a fourth bonded surface 204, the bonded surfaces of the five prism 25 and the six prism 26 form a fifth bonded surface 205, and the bonded surfaces of the six prism 26 and the seven prism 27 form a sixth bonded surface 206, wherein,
the fourth prism 24 is an equilateral right-angled triangle prism, and the first prism 21, the second prism 22, the third prism 23, the fifth prism 25, the sixth prism 26 and the seventh prism 27 are all parallelogram prisms with equal size;
the prism five 25, the prism six 26 and the prism seven 27 are symmetrically distributed with the prism three 23, the prism two 22 and the prism one 21 relative to the prism four 24;
half-wave plates 28 are attached to the emergent surfaces of the first prism 21, the fourth prism 24 and the seventh prism 27;
the first gluing surface 201, the third gluing surface 203, the fourth gluing surface 204 and the sixth gluing surface 206 are all plated with polarization beam splitting films;
the first outer side surface 207, the second bonding surface 202, the fifth bonding surface 205 and the second outer side surface 208 are all plated with total reflection metal films.
In the invention, the incidence surfaces of the second prism 22, the third prism 23, the fifth prism 25 and the sixth prism 26 are all plated with AR antireflection films, so that the transmission utilization rate can be enhanced.
In the invention, the emergent surfaces of the first prism 21, the second prism 22, the third prism 23, the fourth prism 24, the fifth prism 25, the sixth prism 26 and the seventh prism 27 are all plated with AR antireflection films, so that the transmission utilization rate can be enhanced.
In the invention, the polarization beam splitting film is made of MgF 2/ZnS.
In the invention, the size of the incidence surface from the second prism 22 to the sixth prism 26 is the size of the light-emitting source of the LED light source.
The specific implementation process of the invention is as follows:
the LED light source passes through the collimating lens group and then collimates the LED divergent light source, and the size of the light emitting source is from the second prism to the six incident planes of the prism, the collimated light is entered from the second prism, the third prism, the fifth prism and the six incident planes of the prism, and due to the reason of the AR antireflection film, the use efficiency can be improved, and the light is unpolarized light at the moment:
the unpolarized light is divided into horizontal polarized light and vertical polarized light through a third bonding surface (plated with a polarization beam splitting film), the horizontal polarized light is emitted from a fourth emergent surface of the prism through the third bonding surface, and is converted into vertical polarized light after passing through a half-wave plate, the vertical polarized light is reflected by the third bonding surface, and is still vertical polarized light after being emitted from the third emergent surface of the prism through the total reflection of a second bonding surface (plated with a total reflection metal film);
the unpolarized light is totally reflected by the second adhesive surface (plated with a total reflection metal film), passes through the first adhesive surface (polarized beam splitting film), is vertically polarized after being reflected by the first adhesive surface and then emitted out through the second emergent surface of the prism, is horizontally polarized after being transmitted through the second adhesive surface and then reflected by the first outer side surface (plated with the total reflection metal film) and then emitted out through the first emergent surface of the prism, and the surface is plated with an anti-reflection film, so that the transmission utilization rate can be enhanced, and at the moment, the horizontally polarized light passes through a half-wave plate and then is converted into vertically polarized light.
The prism five, the prism six and the prism seven are symmetrically distributed with respect to the prism four, the prism three, the prism two and the prism one. The light direction is exactly the same as the polarization conversion principle.
It should be noted that the above-mentioned embodiments illustrate rather than limit the technical solutions of the present invention, and that equivalent substitutions or other modifications made by those skilled in the art according to the prior art are intended to be included within the scope of the claims of the present invention without departing from the spirit and scope of the technical solutions of the present invention.
Claims (5)
1. A polarization conversion optical system for improving the efficiency of LED backlighting, comprising: the device comprises a collimating lens module and a polarization converter, wherein the polarization converter comprises a first prism, a second prism, a third prism, a fourth prism, a fifth prism, a sixth prism and a seventh prism, inclined planes of the first prism, the second prism, the third prism, the fourth prism, the fifth prism, the sixth prism and the seventh prism are glued into a whole through optical glue, the outer side surface of the first prism forms a first outer side surface, the outer side surface of the seventh prism forms a second outer side surface, the gluing surfaces of the first prism and the second prism form a first gluing surface, the gluing surfaces of the second prism and the third prism form a second gluing surface, the gluing surfaces of the third prism and the fourth prism form a third gluing surface, the gluing surfaces of the fourth prism and the fifth prism form a fourth gluing surface, the gluing surfaces of the fifth prism and the sixth prism form a fifth gluing surface, and the gluing surfaces of the sixth prism and the seventh prism form a sixth gluing surface, wherein,
the fourth prism is an equilateral right-angled triangle prism, and the first prism, the second prism, the third prism, the fifth prism, the sixth prism and the seventh prism are all parallelogram prisms with equal sizes;
the prism five, the prism six and the prism seven are symmetrically distributed with the prism three, the prism two and the prism one relative to the prism four;
half-wave plates are attached to the emergent surfaces of the first prism, the fourth prism and the seventh prism;
the first gluing surface, the third gluing surface, the fourth gluing surface and the sixth gluing surface are plated with polarization beam splitting films;
and the first outer side surface, the second bonding surface, the fifth bonding surface and the second outer side surface are plated with total reflection metal films.
2. The polarization conversion optical system according to claim 1, wherein: and the incidence surfaces of the second prism, the third prism, the fifth prism and the sixth prism are all plated with AR antireflection films.
3. The polarization conversion optical system according to claim 1, wherein: and the emergent surfaces of the first prism, the second prism, the third prism, the fourth prism, the fifth prism, the sixth prism and the seventh prism are all plated with AR antireflection films.
4. The polarization conversion optical system according to claim 1, wherein: the polarization beam splitting film is made of MgF 2/ZnS.
5. The polarization conversion optical system according to claim 1, wherein: and the size of the incidence plane from the second prism to the sixth prism is the size of the light emitting source of the LED light source.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911158640.4A CN110888256A (en) | 2019-11-22 | 2019-11-22 | Polarization conversion optical system for improving LED backlight illumination efficiency |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911158640.4A CN110888256A (en) | 2019-11-22 | 2019-11-22 | Polarization conversion optical system for improving LED backlight illumination efficiency |
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| CN110888256A true CN110888256A (en) | 2020-03-17 |
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| CN201911158640.4A Pending CN110888256A (en) | 2019-11-22 | 2019-11-22 | Polarization conversion optical system for improving LED backlight illumination efficiency |
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