Case 6:20-cv-00139-ADA Document 1-8 Filed 02/21/20 Page 1 of 22
`111111111111111111111111111111111111111111111111111111111111111111111111111
`
`(12) United States Patent
`Vasylyev
`
`(10) Patent No.: US 10,439,089 B2
`Oct. 8, 2019
`(45) Date of Patent:
`
`(54) LIGHT CONVERTING SYSTEM
`EMPLOYING PLANAR LIGHT TRAPPING
`AND LIGHT ABSORBING STRUCTURES
`
`(71) Applicant: Sergiy Vasylye飞 Elk Grove, CA (US)
`
`(72)
`
`Inventor: Sergiy Vasylye飞 Elk Grove, CA (US)
`
`(73) Assignee: SVV TECHNOLOGY
`INNOVATIONS, INC., Sacramento,
`CA (US)
`
`( *) Notice:
`
`Subject to any disclaimer, the term ofthis
`patent is extended or a司justed under 35
`U.S.C. 154(b) by 0 days.
`
`(2014.01)
`(2006.01)
`
`HOlL 31/0525
`G02B 19/00
`(52) U.S. Cl.
`CPC ........ HOlL 31/0547 (2014.12); G01J 1/0407
`(2013.01); G01J 5/θ853 (2013.01); G02B
`5/θ231 (2013.01); G02B 5/0294 (2013.01);
`G02B 19/0028 (2013.01); HOlL 31/02327
`(2013.01); HOlL 31/0525 (2013.01); HOlL
`31/0543 (2014.12); Y02E 10/52 (2013.01)
`(58) Field of Classification Search
`CPC ........... HOIL 31/0525; HOIL 31/02327; H01L
`31/0543; HOIL 31/0547
`USPC .......... 250/216, 203.1 , 203.3, 203 .4; 385/33,
`385/36; 136/246, 256, 259
`See application file for complete search history.
`
`(21) Appl. No.: 16/368,272
`
`(22) Filed:
`
`Mar. 28, 2019
`
`(65)
`
`US 2019/0221699 Al
`
`Prior Publication Data
`Jul. 18, 2019
`
`Related U.S. Application Data
`
`(60) Division of application No. 15/442 ， 645 ，自led on Feb
`25, 2017, now Pat. No. 10,269,999, which is a
`continuation of application No. 14/222,588, filed on
`Mar. 22, 2014, now abandoned, which
`is a
`continuation of application No. 13/181 ,482, filed on
`Jul. 12, 2011 , now Pat. No. 8,735,79 1.
`
`(60) Provisional application No. 61/399 ， 552 ，自led on Jul
`13, 2010, provisional application No. 611402,061 ,
`自led on Aug. 21 , 2010.
`
`(51)
`
`Int. Cl.
`HOlL 27/00
`HOlL 31/054
`G01J 1/04
`G01J 5/08
`G02B 5/02
`HOlL 31/0232
`
`(2006.01)
`(2014.01)
`(2006.01)
`(2006.01)
`(2006.01)
`(2014.01)
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCU肌1ENTS
`
`6,274,860 Bl
`6,333 ,458 Bl
`6,440,769 B2
`7,672,549 B2
`
`8/2001 Rosenberg
`12/2001 Forrest et al.
`8/2002 Peumans et al
`3/2010 Ghosh et al
`(Continued)
`
`Primary Examiner - Kevin K Pyo
`
`ABSTRACT
`(57)
`A light converting optical system employing a planar light
`trapping optical structure illuminated by a source of mono(cid:173)
`chromatic light. The light trapping optical structure includes
`a photoresponsive layer including semiconductor quantum
`dots. The photoresponsive layer is configured at a relatively
`low thickness and located between opposing broad-area
`surfaces that confine and redistribute light within the light
`trapping structure and cause multiple transverse propagation
`of light through the photoresponsive layer to er由ance
`absorption. The light trapping optical structure further incor(cid:173)
`porates optical elements configured for injecting light into
`the light trapping structure.
`
`20 Claims, 7 Drawing Sheets
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`2
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`4
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`24
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`16
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`Case 6:20-cv-00139-ADA Document 1-8 Filed 02/21/20 Page 2 of 22
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`US 10,439,089 B2
`Page 2
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`(56)
`
`References Cited
`
`U.S. PATENT DOCU肌1ENTS
`
`7,817,885 Bl
`10,269,999 B2 *
`2004/0103938 Al
`2008/0264483 Al
`2008/0295882 Al
`2009/0067784 Al
`2009/0126792 Al
`2010/0186798 Al
`2010/0278480 Al
`201110226332 Al
`2012/0012741 Al
`2013/0028565 Al *
`
`GO lJ 110407
`
`10/2010 Vloore et al.
`4/2019 Vasylyev
`6/2004 Rider
`10/2008 Keshner et al
`12/2008 Stephens et al
`3/2009 Ghosh et al.
`5/2009 Gruhlke et al.
`7/2010 Tourmen et al.
`11/2010 Vasylyev
`9/2011 Ford et al
`112012 Vasylyev
`112013 Moore ................ HO lL 3110547
`385/129
`
`* cit巳d by examiner
`
`

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`u.s. Patent
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`Oct. 8, 2019
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`Sheet 1 of 7
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`US 10,439,089 B2
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`24
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`16
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`FI 自愿?
`(PRIORART)
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`(PRIORART)
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`14
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`6
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`U.s. Patent
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`Oct. 8, 2019
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`Sheet 2 of 7
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`US 10,439,089 B2
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`10
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`FIG蝠 4
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`FIG.5
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`10
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`FIG帽 6
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`5
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`u.s. Patent
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`Oct. 8, 2019
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`Sheet 3 of 7
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`US 10,439,089 B2
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`u.s. Patent
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`Oct. 8, 2019
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`Sheet 4 of 7
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`US 10,439,089 B2
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`32
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`u.s. Patent
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`Oct. 8, 2019
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`Sheet 5 of 7
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`US 10,439,089 B2
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`Case 6:20-cv-00139-ADA Document 1-8 Filed 02/21/20 Page 8 of 22
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`u.s. Patent
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`Sheet 6 of 7
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`US 10,439,089 B2
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`Case 6:20-cv-00139-ADA Document 1-8 Filed 02/21/20 Page 9 of 22
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`Sheet 7 of 7
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`Case 6:20-cv-00139-ADA Document 1-8 Filed 02/21/20 Page 10 of 22
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`US 10,439,089 B2
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`1
`LIGHT CONVERTING SYSTEM
`EMPLOYING PLANAR LIGHT TRAPPING
`AND LIGHT ABSORBING STRUCTURES
`
`CROSS-REFERENCE TO RELATED
`APPLICATIONS
`
`2
`One exemplary material suitable for converting light into
`electricity is silicon (Si). However, Si is an indirect bandgap
`semiconductor and is poorly absorbing the long wavelength
`light. For the active layer made with crystalline silicon the
`5 minimum thickness is typically between 200 and 400μm
`(micro-meters). While Si is very abundant, stable and well(cid:173)
`suited for solar cell and light detector manufacturing, the
`卫1is application is a division of application ser-No.cost ofthis thick layer of silicon is quite high which results
`15/442，645 ，自led Fd25, 2017, whichis a cOImMiomfm theMd1cost oftlm dwkes
`10
`Some other than crystalline silicon types of photovoltaic
`application Ser. No. 14/222， 588 ，自led Mar. 22, 2014, which
`morphous silicon thin-film cells, for
`tinuation of application Ser. No. 13/181 ，482 ，自led
`巳xample巳， allow for a much s臼mall巳臼r t也hi比ckn曰巳s臼s of t吐he巳 active
`Jul. 12. 201 1. now U.S. Pat. No. 8.735.791. whi比ch cla剖1m丑lS
`p严rMj卢企…山 严阳川O肝川州V札V1SlO臼Oαm删na蚓1a叫al a叩咐pp叫斗卢……nS山1叶S白;卢T. N陆o. 6ω
`552 且le巳d on Ju让1. 1口3 ， 2010 and from U.S. provisional appli-
`cation Ser. No. 611402,061 filed on Aug. 21 , 2010.
`
`STATEMENT REGARDING FEDERALLY
`SPONS-ÕRED-iESEARCHOR DEVEiü-PMiNT
`
`Not Applicable
`
`INCORPORATION-B￥二REFERENCE OF
`鸟也气TERIAL SUB肌1ITTED ON A CO肌1PACT
`DISC
`
`Not Applicable
`
`NOTICE OF 鸟也气TERIAL SUBJECT TO
`COPYRIGHT PROTECTION
`
`15 light trapping that would cause the incident light to pass
`through the active layer multiple times thus improving the
`absorption. The light trapping is usually implemented in the
`prior artby texturing one or more surfaces comprisill_g the
`solar cell in order to scatter the incident light at different
`20 angles thus resulting in a longer average light path through
`the active layer. In case of a monocrystalline silicon cell,
`li悼t scattering and trapping is conventionally provided by
`microstructures such as periodic or random pyramids on the
`front surface and a reflective or light scattering surface at the
`25 rear of the cell. In case of an amorphous thin-film Si cell
`consisting of several layers, a transparent top conductor
`layer is often textured to scatter light and hence increase the
`light path through the active layer.
`During light trapping, some scattered light can be trapped
`30 in the active layer ofthe solar photovoltaic device by means
`of TIR which can even allow for the multiple passage of a
`A portion of the material in this patent document is su均巳:ct
`to c~pyright protection under the copyright laws of the
`portion of solar rays through the active layer thus resulting
`in a better absorption and sunlight conversion. However, the
`United States- and of other countries~ The owner of the
`existing approaches for. light trapping in the photovoltaic
`copyright rights has no obj 巳:ction to the facsimile reproduc-
`tion by anyone of the patent docum巳nt or the patent- disclo- 35 devices camlOt prevent for a substantial portion of incident
`sure, ~s it ~ppears in th~ United States Patent aiid Trademark
`light to escape from the device without being absorbed. For
`Oflice pub-licly available file or records, but otherwise
`example, in case of the front surface employing random
`pyramidal microstructures, a large portion of the escaping
`reserves all copyright rights whatsoever. The copyri悼t
`owner does not hereby waive any of its rights to have this
`light is usually lost through this front surface due to the
`patent document mai~tained in ~ecrecy， iIÎcluding without 40 random nature ofthe secondary interactions ofthe light rays
`limitation its rights pursuant to 37 C.F.R. S 1.1 4.
`'Nith the pyramids. Furthermore, up to 10 percent or more
`light can be lost in conventional photovoltaic systems due to
`the reflection from front contacts or absorption by layers or
`surfaces which produce no photovoltaic effect
`An additional problem encountered in photovoltaic
`devices is that most photovoltaic materials have a relatively
`The present invention relates to a device and method for
`large refractive index which results in poor light coupling
`efliciency due to the high reflection losses from the light
`harvesting radiant energy emanated by a distant radiant
`r，巳ceiving surface. The bulk crystalline Si, for example, has
`energy source, particularly, to collecting the sunlight and
`absorbing it by a light sensitive material, medium or device. 50 the refractive index of 3.57 at 1,000 mn (nanometers) and
`More particularly, the present invention relates to photovol-
`5.59 at 400 m丑 which results in the Fresnel reflection of 32%
`taic devices, solar cells and light detectors having light
`to 49% of the incident light at 1,000 mn and 400 mn,
`respectively. Typically, these problems can be addressed by
`trapping microstructures or layers to improve absorption of
`light within the light sensitive layer, and to a method for
`adding an antireflective layer to the light receiving surface
`55 and/or surface microstructuring. However, the antireflective
`generating electricity from sunlight ther，巳of.
`coating works efliciently only in a limited bandwidth and
`adds system cost and processing time, while the microstruc(cid:173)
`tures are still somewhat ineflicient for light coupling or
`Conventionally, photovoltaic solar cells or light detectors
`otherwise are quite expensive to be used for mass produc-
`employ an active photoresponsive layer that absorbs at least 60 tion, considering that the entire area of the photovoltaic
`device must be processed to cover it with these microstruc-
`a portion of the electromagnetic spectrum of the light and
`generates charge carriers due to the photovoltaic effect.
`tures.
`Since most photovoltaic materials absorb much more
`These drawbacks of the prior art approaches and the loss
`weakly in certain wavelengths than in the others, the active
`of usefullight are hampering the utility of the photovoltaic
`layer has to have at least a minimum thickness to be able to 65 devices. None of the previous efforts provides an eflicient
`solution for coupling and trapping essentially all of the
`absorb most of the light to which the photovoltaic material
`incident li悼t and allowing it to pass through the suflicient
`is responsive.
`
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`
`45
`
`2. Description of Background Art
`
`

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`BRIEF SUMMARY OF THE INVENTION
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`4
`3
`In at least one implementation, the light harvesting system
`effective depth of photosensitive material or allow the light
`further comprises at least one electrical contact associated
`to interact with the active layer as many times as necessary
`with the photoresponsive layer. In at least one further
`to cause the efficient light absorption in a controlled manner.
`implementation, the electrical contact associated with the
`It is therefore an object of this invention to provide an
`improved light harvesting system employing a novel pho- 5 photoresponsive layer is made from an optically transparent
`material. In at least one implementation, the electrical con-
`tovoltaic structure with efficient light coupling and trapping
`thus minimizing energy loss.
`tact associated with the photoresponsive layer comprises a
`卫le present invention solves the above problems by
`reflωtive metallic material and is made in the form of a grid.
`In at least oneimplementation, theelectrical contact comE
`providing a layered structure having cozelated surface relief
`f四阳res or 1111crostruculms that allow forenhandng theliS1t loprises a rekdivemetallic material and is madein thefom
`COUPIIngemcimcy, 111cream1g thelight path through theof a tl11n sheet or aal111.In at least one1mpleIIMMathAthe
`photosensitive material and for trapping the incident light
`electrical contact comprises a plurality of electrical contact
`within the device by means of at least TIR. The light
`trapping causes multiple passage of the trapp巳dlist1tthroughangers disposed m spaces between a司jacent pairs of light
`the photoresponsive (activ的 layer thus improving thelight 15input poMs and away from the light paths of thefocused
`absorption and energy conversion efficiency. Other 0均~~t~
`beams formed by the light coll巳:cting elements. In at least
`?ne implen:entati~n， .the ~~otoresponsive layer comprises at
`and advantages of this invention will be apparent to tÎlOse
`lea_st o_ne photovoltaic cell.
`skilled in th; art from the following disclo~s~re.
`In altemative implementations, the planar focusing array
`20 and its light collecting elements can be con且gured in dif-
`ferent ways. In at least one implementation, the focusing
`array comprises a lenticular lens array. In at least one
`卫le present invention solves a number of light harvesting
`implementation, the focusing array comprises a point-focus
`problems within a compact system utilizing efficient light
`lens array. In at least one implementation, the focusing array
`coupling and trapping mechanisms. Light is injected into a
`photoresponsive layer through light input ports using a 25 comprises point focus lenses which have a shape selected
`from the group consisting of round, rectangular, square, and
`focusing array and trapped within the layer so that the useful
`hexagonal. In at least one implementation, each of the light
`light absorption is substantially er由anced.
`collecting elements is selected from the group of optical
`A light harvesting system employing microstructures for
`elements consisting of imaging lenses, non-imaging lenses,
`efficient light trapping and comprising a focusing array and
`a photoresponsive layer is described. The focusing array 30 spherical lenses, aspherical lenses, lens arrays, Fresnel
`lenses, TIR lenses, gradient index lenses, diffraction lenses,
`comprises a plurality oflight collecting elements distributed
`mirrors, Fresnel mirrors, spherical mirrors, parabolic mir-
`over a planar surface of the array. Each light collωting
`rors, mirror arrays, and trough mirrors
`element is configured to collωt light from a larger ar四 and
`In different implementations, the plurality of light input
`focus the incident light onto a substantially smaller focal
`area. The photoresponsive layer comprises light input ports 35 ports can be differently configured. In at least one imple-
`mentation, each of the plurality of light input ports is
`formed in its light receiving surface. Each light input port is
`dispos巳d in a predeterr丑ined aligument with the plurality of
`disposed in energy receiving relationship with respect to at
`light collecting elements. In at least one implementation, the
`least one light collecting element ofthe focusing array. More
`particularly, each light input port is disposed in a vicinity of
`oblique propagation angle within the photoresponsive layer
`the respective light collecting element and aligned (cen- 40 is so selected as to result in the propagation of at least a
`substantial portion of light rays at sufficiently high angles,
`tered) with respect to its optical axis. Each light input port
`is configured to receive a focused light beam and commu-
`above the predetermined critical angle for total intemal
`refl巳:ction (TIR), with respect to a surface normal to at least
`nicate it into the photoresponsive layer a sufficiently oblique
`angle so as to result in an improved light coupling and
`one surface of said photoresponsive layer. In at least one
`generally increased light path and absorption in said layer 45 implementation, each of the plurality of light input ports
`compared to the case when light enters the photoresponsive
`comprises a refractive or reflective face inclined at an angle
`with respect to the prevailing plane of the photoresponsive
`layer elsewhere through its light receiving surface.
`layer. In at least one implementation, the plurality of light
`The invention is amenable to being embodied in a number
`ofways, including but not limited to the following descrip-
`input ports comprises a parallel array of elongated grooves.
`50 In at least one implementation, each ofthe plurality of light
`tions.
`At least one embodiment ofthe invention is con且gured as
`input ports comprises at least one cavity. In at least one
`implementation, the cavity has a sufficiently high aspect
`a light har飞咄ting system comprising: (a) a photoresponsive
`ratio. In at least one implementation, each ofthe light input
`layer configured to internally absorb at least a portion ofthe
`light propagating through its body; (b) a plurality of light
`ports comprises at least one surface relief feature selected
`input ports associated with a light receiving surface of said 55 from the group of elements consisting of cavities, holes,
`extensions, bulges, prisms, prismatic grooves, cones, conical
`photoresponsive layer; and (c) a plurality of light collecting
`cavities, furmel-shaped cavities, surface texture, reflective
`elements within a planar focusing array con且gured for
`surfaces, refractive surfaces, diffraction gratings, holograms,
`focusing received light onto said light input ports. Each of
`light scattering elements, and so forth.
`the plurality of light input ports is configured to communi-
`In further implementations, the light harvesting system
`cate the incident light into the photoresponsive layer at a 60
`can be configured in various ways to enhance the light
`sufficiently oblique angle so as to increase the optical path
`of the light rays through the designated layer. The device
`trapping in the photoresponsive layer. In at least one imple-
`mentation, the light harvesting system further comprises an
`operates in response to the light received on the aperture of
`the focusing array being injected into the photoresponsive
`optical interface dispos巳d between the photoresponsive
`layer and angularly redirected at generally oblique angles 65 layer and the focusing array and characterized by a drop in
`re企active index in the direction of light propagation from
`with respect to the prevailing plane of the light har飞咄ting
`system.
`the photoresponsive layer toward the focusing array. In at
`
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`5
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`least one implementation, the light harvesting system further
`Another element of the invention is the use of contact
`fingers associated with the light receiving surface of the
`comprises means for promoting a total intemal reflection in
`photovoltaic layer and disposed in the spaces between the
`the photoresponsive layer.
`In at least one implementation, the focusing array and the
`pairs of a司jacent light input ports and away from the light
`photoresponsive layer are adapted for being retained in a 5 paths of the focused beams formed by the light collecting
`translated, a reversed and/or a rotated orientation relative to
`elements.
`Another element of the invention is the use of linear
`each other toward a司justing the acceptance angle or for
`tracking thesourceof light.In at least onetbrther imPIe-aITays of light collectingelements and/or light input poMs
`which span tlmsurface of thedevice, or a portion thereof.
`meIHathAtlmlIdH harvesting system can compnseat least
`one tracking m四ns for tracking a light source.
`10 Alternatively, another element of the invention is the use of
`At least one embodiment ofthe invention is configured as
`point-focus arrays of light collectmgelementsmdor lIght
`a light harvesting system having a layered structureand
`comprising:(a)a photovoltaic layer disposed between a ant
`Input ports as well as portIons and combmatIons of linear
`a~d-ra- ~~~~nd ~efi~~tive sllrfa~e~; ~nd \b) a light focusing
`and point击cus arrays thereof.
`layer havmg surface relIef featureseach conasured to focus 15Another element of theInvent1on is the useof a pmdeE
`th~ incident lillht. At least one of the first and second
`termined alignment for disposing the light collecting ele-
`reflective surfa~es comprises light input ports disposed in
`ments with respect to the light input ports and/or the
`energy receiving relati~nship t~ the iurf~ce relie{ features
`electrical contacts
`Another element of the invention is the use of light input
`and configured to inject incident light into the space be阳en
`the first and sωond reflective surfaces so as to cause 20 ports in the form of caviti郎， holes or other microstructures
`multiple passage of light through the photovoltaic layer.
`having a sufliciently high aspect ratio.
`In at least one implementation, at least one of the first and
`Another element of the invention is the use of light input
`S巳:cond reflective surfaces is configured for reflecting light
`ports each comprising a refractive or refl巳'ctive face inclined
`by means of at least TIR. In at least one implementation, the
`at an angle to the light recei飞ring surface ofthe photorespon-
`light harvesting system is further comprising at least one 25 sive layer for ir可 ecting at least a substantial part of the
`incident light into the layer at an oblique angle.
`cladding layer associated with at least one of the first and
`S巳cond renedivesurfaces.In at least om implementation, at
`Anotherelement of theinvention is theuseof tracking
`least one of the 曲st and second reflective sur丰ces lS
`means for tracking a light source
`assOCIatd WIth a mirror layer comprisms a metall1c mate-A stillaIrtherelement oftheinvent101118 a light harvestmg
`rial.In at least oneimplementation, at least oneof tlmarst30system wl11ch can beut1lindm a wide rangeof lIght
`and second reflective surfaces is associated with a mirror
`collecting or light sensing applications
`layer comprising a Bragg reflector. In at least one imple-
`Further elements of the invention will be brought out in
`mentation, the light focusing layer comprises a lens array. In
`at least oneImplementation, thephotoVoltaIC layer comEthefollowing portions of thespeciacation, wherein the
`prises at least onephotovoltaic cell-In at least oneimPIe-35detailed description is for thepuIposeof tblly disclosing
`~entation， the photovoltaic layer is associated with at I~ast
`?re~err巳d embodiments of the invention without placing
`one light detect~r. In at least or{e implementation, each ofthe
`limitations thereon.
`light input ports is formed by a microstructured area in at
`least one of the first and second reflective surfaces
`卫le present invention provides a number of beneficial 40
`elements which can be implemented either separately or in
`The invention will be more fully understood by reference
`any desired combination without departing from the present
`to the following drawings which are for illustrative purposes
`teachings.
`An element of the invention is a light har飞咄ting system
`only:
`collecting light over a given area and communicating the 45
`FIG. 1 and FIG. 2 are schematic diagrams and ray tracing
`incident light into a photoresponsive layer, such as a pho-
`for conventional photovoltaic systems.
`tovoltaic layer, with an 巳nhanced light coupling efliciency
`FIG. 3 is a schematic view and ray tracing of a light
`harvesting system in accordance with at least one embodi-
`and with increasing the light path through the photorespon-
`ment of the present invention.
`sive layer.
`Another element of the invention is a plurality of light 50
`FIG. 4 is a perspective view of a focusing array according
`collecting elements within a focusing array which collωto at least one embodiment of the present invention, showing
`the use of a planar lenticular lens array
`tively collect the incident light over a broad area and focus
`it into a plurality of small-aperture focal areas.
`FIG. 5 is a perspective top view a focusing array accord-
`ing to at least one embodiment of the present invention,
`Another element of the invention is the inclusion of
`distributed light input ports, such as areas having surface 55 showing the use of a planar lens array employing point focus
`relief features, microstructures or texture, associated with a
`lenses.
`light receiving surface or the interior of photoresponsive
`FIG. 6 is a perspective top view of a focusing array
`according to at least one embodiment of the present inven-
`layer and disposing them in a light receiving relationship to
`tion, showing a different arrangement and shapes of point
`the light collecting elements of the focusing array.
`Another element of the invention is the inclusion of one 60 focus lenses than were shown in FIG. 5.
`or more cladding layers or mirrored surfaces to er由ance
`FIG. 7 is a schematic view of a photovoltaic layer portion
`comprising an elongated V-shape groove, according to at
`respectively the total intemal reflection or the specular
`reflection of light within the photoresponsive layer.
`least one embodiment of the present invention.
`Another element of the invention is the use of electrical
`FIG. 8 is a schematic view of a photovoltaic layer portion
`contacts which can additionally be provided with enhanced 65 comprising a V-shape groove which has a shorter length than
`the elongated grove shown in FIG. 7, according to at least
`reflective properties to promote retaining the light within the
`one embodiment of the present invention
`photoresponsive layer.
`
`BRIEF DESCRIPTION OF THE SEVERAL
`VIEWS OF THE DRAWING(S)
`
`

`

`Case 6:20-cv-00139-ADA Document 1-8 Filed 02/21/20 Page 13 of 22
`
`US 10,439,089 B2
`
`8
`7
`crystalline silicon (Si) solar cell typically employing a
`FIG. 9 is a schematic view of a photovoltaic layer portion
`comprising a cavity having a pyramidal shape, according to
`photovoltaic layer 4 of mono- or polycrystalline silicon with
`at least one embodiment of the present invention.
`a p-n junction formed by joining n-type and p-type Si.
`Individual rays interacting with the photovoltaic structure
`FIG. 10 is a schematic view of a photovoltaic layer
`5 are illustrated by line segments that, by way of example and
`portion comprising a cavity having a conical shape, accord-
`not limitation, can represent the paths of individual photons
`ing to at least one embodiment of the present invention.
`of the incident light beam or otherwise represent possible
`FIG. 11 is a schematic view of a portion of light harvest-
`li悼t paths. In FIG. 1, a front contact is formed by contact
`ing system according to at least one embodiment of the
`fingers 24 attached to a front surface 32 of photovoltaic layer
`present invention.
`FIG. 12 is a ray tracing of an incident ray being injected 10 4 and a back contact 16 is formed by a metallic layer
`attached to a back surface 34 of photovoltaic layer 4
`into a photovoltaic layer at oblique angles by a V-shaped
`cavity formed in a photovoltaic layer surface, according to
`Referring further to FIG. 1, an incident light ray 100
`at least one embodiment of the present invention.
`emanated by a distant source and entering photovoltaic layer
`FIG. 13 is a ray tracing of an incident ray being injected
`4 is absorbed within this layer with the generation of an
`into a photovoltaic layer by a funnel-shaped cavity or groove 15 electron-hole pair 50 due to the photo effect. The front and
`having cur飞rilinear walls, according to at least one embodi-
`back contacts of the cell collect the charge carriers thus
`ment of the present invention.
`generating useful photocurrent in an extemal circuit (not
`FIG. 14 is a ray tracing of an incident ray being injected
`shown). Aray 102 strikes a contact finger 24 and is absorbed
`into a photovoltaic layer through a blind hole form巳，d in a
`or scattered without photocurrent generation. A ray 104
`photovoltaic layer surface, according to at least one embodi- 20 entering photovoltaic layer 4 is reflected from back contact
`ment of the present invention.
`16 and exits back into the environment without being
`FIG. 15 is a ray tracing of an incident ray being injected
`absorbed and thus without producing the photocurrent.
`into a photovoltaic layer via a through hole, according to at
`Finally, a ray 106 striking front surface 32 of photovoltaic
`least one embodiment of the present invention.
`layer 4 is reflect巳d from the surface without penetration into
`FIG. 16 is a schematic ray tracing diagram of light 25 the photoactive layer and without useful absorption. Thus,
`trapping in a photovoltaic layer, according to at least one
`ray 100 represents a useful, absorbed photon or photons
`while rays 102, 104 and 106 represent photons that are lost
`embodiment of the present invention.
`due to various optical loss mechanisms. It should be noted
`FIG. 17 is a schematic view and ray tracing of a light
`harvesting system portion further incorporating a layer of
`that the light rays shown in FIG. 1 do not necessarily
`transparent material between a focusing array and a photo- 30 represent all possible light paths or absorption and loss
`voltaic layer, according to at least one embodiment of the
`scenarios and are merely provided for the purpose of illus-
`trating some of the most common loss m巳'chanisms.
`present invention.
`In FIG. 2, a conventional pyramid microstructure of the
`FIG. 18 is a schematic perspωtive view and raytracing of
`a light har飞咄ting system portion in which light input ports
`photovoltaic cells is illustrated along with the typical light
`are formed by textures areas in a photovoltaic layer, accord- 35 trapping mechanism (the front contacts, p-n structure and
`other layers customary to photovoltaic devices, such as
`ing to at least one embodiment of the present invention.
`passivation, diffusion, antireflective layers, etc., are not
`FIG. 19 is a schematic perspective view of a photovoltaic
`layer portion incorporating a plurality of prismatic surface
`shown here for clarity). When a ray 108 strikes the surface
`relief features, according to at least one embodiment of the
`of a pyr缸口id formed in the front surface of photovoltaic
`40 layer 4 and if it is reflected from the pyramid surface, it has
`present invention.
`another chance to enter layer 4 through the surface of an
`a句 acent pyramid. Thus, the overall surface reflectivity is
`somewhat reduced compared to the flat surface having no
`microstructures. Furthermore, since ray 108 now enters
`Referring more specifically to the drawings, for illustra- 45 layer 4 at a greater angle with respect to the surface normal,
`tive purposes the present invention is embodied in the
`its effective path through the photoresponsive material is
`apparatus generally shown in the preceding figures. It will be
`increased which can result in better light absorption
`However, ray 108 bouncing from back contact 16 exits
`appreciated that the apparatus may vary as to configuration
`layer 4 the next time it interacts with the front surface. It will
`and as to details of the parts without departing from the basic
`concepts as disclosed herein. Furthermore, elements repre- 50 be appreciated by those skilled in the art, that if the chance
`of light reflection from the front surface of layer 4 is further
`sented in one embodiment as taught herein are applicable
`without limitation to other embodiments taught herein, and
`reduced and if the effective light path in layer 4 is 旬出er
`extended, the useful light absorption will increase thus
`in combination with those embodiments and what is known
`in the art.
`resul