(54)
`
`(75)
`
`Inventors:
`
`Rick L. Shie, Westlake Village, CA
`(US); Jeffrey A. Laine, Redondo
`Beach, CA (US); Gajendra D. Savant,
`Torrance, CA (US); Tomasz P.
`Jannson, Torrance, CA (US)
`
`(73)
`
`Assignee:
`
`Physical Optics Corporation,
`Torrance, CA (US)
`
`Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`US.C. 154(b) by 0 days.
`
`(21)
`
`(22)
`
`(65)
`
`(62)
`
`(61)
`(52)
`
`Appl. No.:
`Filed:
`
`09/851,815
`
`May9, 2001
`Prior Publication Data
`
`US 2001/0017970 Al Aug. 30, 2001
`
`Related U.S. Application Data
`Division of application No. 09/139,488,filed on Aug. 25,
`1998, now Pat. No. 6,266,476.
`
`Int. Cl.” ..
`US. Cl.
`..
`
`secessssssvecesesssuesessssveessssssetsssaseeecs G02B 6/00
`secesessssesssessseee 385/133; 385/146; 359/566
`
`[4
`
`
`
`a2, United States Patent
`US 6,483,976 B2
`(10) Patent No.:
`Nov. 19, 2002
`(45) Date of Patent:
`Shie et al.
`
`US006483976B2
`
`OPTICAL ELEMENT HAVING AN
`INTEGRAL SURFACE DIFFUSER
`
`(58) Field of Search oo... eee 385/146-147,
`385/133, 141; 359/443, 566, 707, 742
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`8/1994 Rudisill et al... 359/49
`5,339,179 A *
`
`5,854,872 A * 12/1998 Tai oe wo. 385/133
`6,266,476 B1 *
`7/2001 Shie et al. 0... 385/147
`
`* cited by examiner
`
`Primary Examiner—Ellen E. Kim
`(74) Attorney, Agent, or Firm—Nilles & Nilles; Leonard
`Tachner
`
`(57)
`
`ABSTRACT
`
`A monolithic element has a substrate body andat least one
`macro-optical characteristic integral in a first portion of the
`optical element. A plurality of surface micro-structures are
`integral in a portion of the optical element. The micro-
`structures are designed to homogenizelight passing through
`the optical element to produce a predetermined pattern of
`smoothly varying, non-discontinuouslight exiting the opti-
`cal element. Thelight exiting the optical elementis therefore
`altered according to both the macro-optical characteristic of
`the optical element as well as the homogenizing character-
`istics of the micro-structures.
`
`15 Claims, 3 Drawing Sheets
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`

`U.S. Patent
`
`Nov. 19, 2002
`
`Sheet 1 of 3
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`US 6,483,976 B2
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`U.S. Patent
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`Nov. 19, 2002
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`Sheet 2 of 3
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`US 6,483,976 B2
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`U.S. Patent
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`Nov. 19, 2002
`
`Sheet 3 of 3
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`US 6,483,976 B2
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`

`US 6,483,976 B2
`
`1
`OPTICAL ELEMENT HAVING AN
`INTEGRAL SURFACE DIFFUSER
`
`The present application is a divisional application of U.S.
`patent application Ser. No. 09/139,488, filed Aug. 25, 1998,
`now patented with U.S. Pat. No. 6,266,476.
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`
`2
`lens or lenses and the materials utilized to manufacture the
`lens. A Fresnel lens includes a plurality of Fresnel structures
`provided on a surface of the lens which bend orrefract the
`light in order to collimate or focus light passing through the
`lens. Many other optical elements are available which per-
`form a particular optical function on light. These optical
`elements are not capable of smoothing out or “homogeniz-
`ing”the light intensity variations exiting the optical element
`or directing substantially all of the light
`in a particular
`direction and in a particular shape, envelope, or pattern.
`The present invention relates generally to the field of
`Consequently,
`in prior art optical elements, a significant
`optics, and more particularly to various optical elements
`amount of light is lost or wasted.
`incorporating an integral surface diffuser as a portion of the
`Diffusers have been applied as a separate layer to optical
`optical element.
`elements in order to add both light diffusing and directing
`2. Description of the Related Art
`characteristics. In such a construction, a laminate is formed
`There are many types of optical elements useful for an
`including a sheet or a layer of diffuser material applied or
`endless number of current and new applications. These
`adhered to a surface of an optical element, such as for
`optical elements are placed in a beam orpath of light to
`example, a Fresnel lens. One problem with such a construc-
`change the characteristics of the light passing through the
`tion is that the sheet material is not very durable andis easily
`optical elements. Such optical elements may be as simple as
`damaged, scratched or otherwise deformed during use.
`a conventional cylindrical
`lens where a beam of light
`Another problem is that the diffuser sheet metal may simply
`entering the lens remains unaffected in its width and is
`peel away from the optical element over time or under
`spread by the cylindrical lens contour in a direction perpen-
`certain conditions. Another even morecritical problem with
`dicular to its width. An example of another optical element
`such a laminate construction is that the mating surfaces
`25
`is a transparent medium havingaflat surface on one side and
`between the two portions of the laminate create an interface
`a concaveor convexsurface on the other side which changes
`which refracts or reflects a portion of light entering the
`the characteristics of light passing through the lens. Such
`optical element. This Fresnel reflection causes a minimum
`lenses are commonly used for eyeglasses, magnifying
`loss of 4% ofthe incidentlight at each mating surface which
`glasses, film projectors and similar objects.
`therefore does not pass through the diffuser and optical
`elementoris otherwise altered in an undesirable manner. A
`Other types of optical elements are known and may
`include Fresnel structures, grating structures, filters, Total
`internal reflection (TIR) structures, nonlinear optical ele-
`ments such as GRINlenses, prismatic structures, polarizers,
`pillow optic formations,fiber optic cables and other types of
`optical wave guides. All of these structures receive a light
`input from a light source and transmit or reflect the light
`through the structure or element and then permitthe light to
`exit from the structure or element in a somewhat altered
`state. All of these types of optical elements either transmit,
`reflect, diffract, refract, or filter out certain wavelengths of
`the light as it exits the structure or element.
`Eachof these optical elements receives light from a light
`source having particular characteristics defined by the prop-
`erties of the light source and thenalter the light propagating
`through the optical element. However, none of these optical
`elements is capable of improving the optical qualities of the
`light in a manner which evens or smoothes out the light by
`eliminating high-intensity spots and low-intensity spots
`within the source. By evenly diffusing the light traveling in
`or through the optical element the output is made smooth
`and non-discontinuous. Additionally, none of these types of
`optical elements is capable of substantially reducing or
`eliminating scatter of light and directing substantially all or
`most of the light photons in a particular desired direction,
`pattern, or envelope. Virtually all of these knownoptical
`elements merely perform a particular optical function as
`light passes throughorreflects off of the element.
`For example, a fiber optic cable is designedto takein light
`energy at one end andvia the predeterminedrefractive index
`of the fiber materials (core and cladding) continually and
`internally reflects the light as it passes through the fiber so
`that essentially all the light exits the fiber optic cable in
`substantially the same form in which it was received
`(ignoring modal variations). Convex lenses used in such
`objects as eyeglasses and projector lenses (which use mul-
`tiple lenses) slightly bend the lightas it enters one side of the
`lens according to the amount of curvature or shape of the
`
`further problem with such a construction is that an index
`matching optical grade epoxy or adhesive must be used in
`order to adhere the two parts of the laminate together. The
`optical grade epoxy permits passage of light through itself
`but creates an additional layer or refractive surface at each
`contact point, and hence additional Fresnel
`losses, both
`between the diffuser layer and the epoxy and between the
`optical element and the epoxy. The epoxy layer also adds
`cost to the laminate construction as well as manufacturing
`complexity. Another problem with the epoxy is that there
`may be instances where the epoxyis not in complete contact
`with one surface of the laminate or has air bubbles between
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`the epoxy and oneof the laminate layers or within the epoxy
`itself. Such irregularities cause further problems (ie.,
`scattering) with light passing within the laminate optical
`element. All the above problems greatly reduce the perfor-
`manceand desirability of laminated optical elements.
`The assignee of the present invention has invented several
`ways of forming a plurality of surface micro-structures in
`various materials to form a surface diffuser on such mate-
`rials. These methods are described in a numberof issued
`
`patents and co-pending patent applications listed below.
`Manyof these methods involve creating a master diffuser by
`exposing a photoresist material to a source of light and then
`replicating this master diffuser into one or more submasters
`of a more durable nature. There are also other methods of
`
`making replicas of a master diffuser which contain the
`optical features in the master. With some of these methods,
`the master diffuser is initially created optically. With others,
`it is created mechanically. Submasters are created from these
`master diffusers utilizing a number of methods whereby the
`master diffuser surface is replicated into a submaster surface.
`These other methods are described in one or more pending
`US. applications, referenced below, which are assigned to
`the assignee of the present invention.
`Other commonly assigned U.S. patents and pending
`applications disclose related methods for making and
`
`5
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`

`

`US 6,483,976 B2
`
`3
`recording optical products and replicating those products so
`that they may be mass produced. For example, U.S. Pat. No.
`5,365,354 entitled “Grin Type Diffuser Based on Volume
`Holographic Material,” U.S. Pat. No. 5,534,386 entitled
`“Homogenizer Formed Using Coherent Light and a Holo-
`graphic Diffuser,” and U.S. Pat. No. 5,609,939 entitled
`“Viewing Screen Formed Using Coherent Light,” all owned
`by the present assignee relate to methods for recording and
`replicating optical products. Each of these U.S. patents is
`incorporated herein by reference for purposesincluding, but
`not limited to,
`indicating the background of the present
`invention and illustrating the state of the art.
`Related U.S. patent applications include Ser. No. 08/782,
`962 entitled “Apparatus for LCD Backlighting,” now US.
`Pat. No. 6,072,551, Ser. No. 09/052,586 entitled “Method of
`Making Replicas While Preserving Master,” now U.S. Pat.
`No. 6,159,398, Ser. No. 08/595,307 entitled “LCD With
`Light Source Destructuring and Shaping Device,” now U.S.
`Pat. No. 5,956,106 Ser. No. 08/601,133 entitled “Liquid
`Crystal Display System with Collimated Backlighting and
`Non-Lambertian Diffusing,” now U.S. Pat. No. 5,838,403,
`Ser. No. 08/618,539 entitled “Method of Making Liquid
`Crystal Display System,” now U-S. Pat. No. 5,735,988, Ser.
`No. 08/800,872 entitled “Method of Making Replicas and
`Compositions for Use Therewith,” now U.S. Pat. No. 5,922,
`238, and Ser. No. 09/075,023 entitled “Method and Appa-
`ratus for Making Optical Masters Using Incoherent Light,”
`“Non-Lambertian Glass Diffuser and Method of Making,”
`filed Aug. 20, 1998, “Diffuser Master and Method of
`Manufacture,” filed Aug. 20, 1998, “High Efficiency Mono-
`lithic Glass Light Shaping Diffuser and Method of Making,”
`filed Aug. 25, 1998, “Vehicle Light Assembly Including a
`Diffuser Surface Structure,” filed Aug. 25, 1998, “Apparatus
`Having a Light Source and a Sol-Gel Monolithic Diffuser,”
`filed Aug. 25, 1998, “Passive Matrix Liquid Crystal
`Display,” filed Aug. 25, 1998, and “Device Including an
`Optical Element With a Diffuser,” filed Aug. 25, 1998. All
`the above applications are owned by the present assignee
`and are hereby incorporated by reference for purposes
`including, but not limited to, indicating the background of
`the present invention andillustrating the state of the art.
`SUMMARYOF THE INVENTION
`
`A monolithic optical element constructed in accordance
`with the present invention has a substrate body with at least
`one macro-optical characteristic integral in a first portion of
`the optical element. The monolithic optical element also
`includesa plurality of surface micro-structures integral in a
`portion of the optical element wherein the micro-structures
`homogenize light passing through the optical element to
`produce a predetermined pattern of smoothly varying, non-
`discontinuous light which exits the optical element.
`It is an object of the present invention to provide an
`optical element which both has at least one macro-optical
`characteristic as well as a light diffusing and shaping surface
`structure provided by the surface micro-surface structures
`integral in a portion of the optical element. It is a further
`object of the present invention to provide such a monolithic
`optical element which is formed of one single body of
`material and is not a laminate construction. It is a further
`object of the present
`invention to provide a monolithic
`optical element which eliminates the lossy reflective abut-
`ting surface between two components of a laminate which
`would otherwise create unwanted Fresnel reflection losses of
`
`4% at each surface, and thus which substantially increases
`transmission efficiency over the prior art. It is a still further
`object of the present
`invention to provide a monolithic
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`optical element wherein the surface micro-structures of the
`diffuser surface are formed integral from the same material
`as the remainder of the optical element to provide a more
`durable and substantially more useful element and one
`which is less expensive to manufacture.
`In one embodiment,
`the substrate body of the optical
`element is a Fresnel lens wherein the at least one macro-
`optical characteristic is a plurality of Fresnel optics. In
`another embodiment, the substrate body is an elongate fiber
`optic cable or optical waveguide and the at
`least one
`macro-optical characteristic is a refractive index or indices
`of the cable. In other embodiments of the invention, the
`monolithic optical element is any type of optical lens such
`as a concaveor convexlens, an aspheric lens, a polarizer, a
`prismatic structure, a filter, a grating structure, or a total
`internal reflection lens wedge (“light pipe”), or retroreflec-
`tor. In yet another embodiment the monolithic optical ele-
`ment is a lightpipe such as for use in a laptop computer
`display. In any of these embodiments, the particular lens
`characteristic or structure is formed integral as a portion of
`the substrate body and the micro-structures which provide
`the diffusing and light shaping characteristics are also
`formed integral in a portion of the substrate body. In one
`embodiment, the micro-structures are formed integral in a
`portion of the substrate body separate from the macro-
`optical characteristic.
`In an alternative embodiment,
`the
`micro-structures are formed integral in the same surface of
`the optical element as the macro-optical characteristic.
`These and other aspects and objects of the present inven-
`tion will be better appreciated and understood when con-
`sidered in conjunction with the following description and
`accompanying drawings. It should be understood, however,
`that the following description, while indicating preferred
`embodiments of the present invention as given by way of
`illustration and not of limitation. Many changes and modi-
`fications may be made within the scope of the present
`invention without departing from the spirit thereof and the
`invention includes all such modifications.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`A clear conception of the advantages and features of the
`present invention, and of the construction and operation of
`the typical mechanismsprovided with the present invention,
`will become more readily apparent by referring to the
`exemplary and therefore nonlimiting embodiments illus-
`trated in the drawings accompanying informinga partofthis
`specification, and in which:
`FIG. 1a illustrates an elevational perspective view of a
`Fresnel lens optical element;
`FIG. 1b illustrates a cross-sectional view taken along line
`1b—1bof the Fresnel lens of FIG. 1a;
`FIG. 2a illustrates an elevational perspective view of a
`cylindrical lens optical element;
`FIG. 25 illustrates a cross-sectional view of the cylindri-
`cal lens taken along line 2b—2b of FIG. 2a;
`FIGS. 2c and 2d illustrate a cross-sectional view of
`alternative cylindrical lens optical elements;
`FIG. 3a illustrates an elevational perspective view of a
`parabolic convex lens optical elements;
`FIG. 35 illustrates a cross-sectional view taken along line
`3b—3bof the convex lens of FIG. 3a;
`FIG. 4a illustrates an elevational perspective view of a
`fiber optic cable optical element;
`FIG. 4billustrates a cross-sectional view taken along line
`4b—4b ofthe fiber optic cable of FIG. 4a;
`
`6
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`

`

`US 6,483,976 B2
`
`5
`FIG. 5a illustrates an elevational perspective view of a
`prismatic optical element;
`FIG. 5b illustrates a cross-sectional view taken along line
`5b—5b of the prismatic optical element of FIG. 5a;
`FIG. 6a illustrates an elevational perspective view of a
`polarizer optical element;
`FIG. 6b illustrates a cross-sectional view taken along line
`6b—6b of the polarizer optical element of FIG. 6a;
`FIG. 7a illustrates a wave guide filter grating optical
`element;
`FIG. 7b illustrates a cross-sectional view of the wave
`guide filter grating taken along line 7)—7b of FIG. 7a;
`FIG. 8a illustrates an elevational perspective view of a
`parabolic concave lens optical element;
`FIG. 8b illustrates a cross-sectional view taken along line
`8b—8bof the concave lens of FIG. 8a;
`FIG. 9 illustrates a simple schematic view oftotal internal
`reflection optical element;
`FIGS. 10a and 10b illustrate a cross-sectional view of
`
`alternative embodiments of an optical element of the inven-
`tion; and
`FIG. 11 illustrates a light pipe alternative embodiment
`according to the invention.
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`
`According to the above listed patents and co-pending
`patent applications assigned to the assignee of the present
`invention, methods have been developed by the assignee for
`optically or mechanically creating micro-sculpted surface
`structures or micro-structures in a substrate which are ran-
`dom in nature and produce a light output with a smooth
`consistent and continuous intensity. These micro-structures
`can also be created in such a mannerso as to control the
`direction of light output from a light source so as to shape
`the light output into a desired distribution pattern or enve-
`lope. The issued patents are directed to forming these
`surface structures by various meansin photoresist materials
`and replicating theses structures in sub-masters. These sub-
`masters are utilized to further replicate the micro-structures
`in sheets of material which may be laminated or otherwise
`applied to objects in order
`to provide the light
`homogenizing, shaping and directing characteristics. The
`co-pending applications disclose the further developed tech-
`niques for novelly forming these micro-structures in mate-
`rials other than in epoxy and sheets of soft plastic.
`The present inventionis not to be limited to forming these
`micro-structures in any particular material and therefore the
`optical elements described herein may be formed from such
`materials as sol-gel glass, quartz glass, polycarbonate and
`acrylic plastics, epoxies, and any other suitable plastic, glass
`or other moldable materials. The present
`invention is
`directed to optical elements having integrally formed micro-
`structures to produce a monolithic structure having both the
`macro-optical characteristic associated with a particular
`optical element as well as the diffuser micro-structures to
`improve the characteristics of the light propagating
`therethrough,
`to minimize unwanted Fresnel reflection
`losses and thereby actually increase transmission efficiency,
`and to decrease cost of manufacture.
`
`Referring now to the drawings, the figures illustrate a
`number of possible embodiments of particular optical ele-
`ments which incorporate the micro-structure integrally into
`the optical element
`to form a monolithic structure with
`improved and defined light propagation characteristics. The
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`embodiments shownare not intended to exhaust thelist of
`possible optical elements but merely to illustrate some of the
`possibilities. FIGS. 1a and 1b illustrate an optical element in
`the form of a Fresnel lens 20. A Fresnel lens is typically
`utilized in many applications for taking light from a light
`source and spreading, collimating, or focusing the light
`accordingto the structural characteristics of the Fresnellens.
`For example, a Fresnel lens is typically utilized in many
`automotive applications for objects as simple as interior
`dome lights, simple trailer lights and in various vehicle
`taillamp construction.
`A Fresnel lens 20 constructed in accordance with the
`present invention includesa substrate body 22 which may be
`formed of any numberof materials but in many applications
`is molded from a plastic material. Additionally, the substrate
`body 22 may be formed in any numberof shapes, configu-
`rations and contours without departing from the scopeof the
`present invention although the lens 20 is simply shown as a
`planar structure. A conventional Fresnel lens 20 has on one
`surface thereof a plurality of Fresnel optics 24. These
`structures are typically in the form of a plurality of circular
`or oval shaped continuousor discontinuousridges disposed
`radially outward from a centeraxis relative to one another on
`the surface of the substrate body 22. The particular size,
`cross-sectional shape and contour of the Fresnel optics as
`well as the size, curvature, and frequency of the continuous
`rings determine the macro-optical characteristic of a par-
`ticular Fresnel lens 20. The Fresnel lens 20 constructed in
`accordance with the invention however also includes a
`plurality of surface micro-structures 26 molded into the
`opposite side of the substrate body 22 according to one of
`the several methods disclosed in the above noted pending
`applications. These micro-structures can be molded or
`embossed directly into this substrate body 22 during forma-
`tion of the Fresnel lens 20 from a master substrate. The
`
`master substrate can be formed from a multi-step optical
`recording process or form one of several novel mechanical
`means such as brushing, etching or shot blasting of the
`substrate as described in one or more of the above incorpo-
`rated patents and patent applications. The result is a mono-
`lithic body 22 including both the macro-optical character-
`istic Fresnel optics 24 on one surface and the micro-
`structures 26 on another surface of the body.
`FIGS. 2a and 25illustrate an optical element in the form
`of a cylindrical
`lens 30. The cylindrical
`lens 30 has a
`substrate body 32 which on oneside includes an elongate
`cylindrical surface 34 defining the macro-optical character-
`istic of the lens. The opposite side of the substrate body 32
`includes a plurality of the micro-structures 36 which define
`the diffuser surface formed by the several methods disclosed
`in the above noted co-pending United States patent and
`patent applications. FIGS. 2c and 2d illustrate alternative
`embodiments of cylindrical lens structures 37 and 41. FIG.
`2c illustrates a substrate body 38 having thereon a plurality
`of cylindrical lenses 40 on one side and a plurality of the
`micro-structures 36 formed on the other side of the substrate
`
`38. FIG. 2d illustrates an alternative substrate body 42
`having thereon a plurality of inverted or reverse cylindrical
`lenses 44 formed thereon. The micro-structures 36 are
`
`formed on the opposite side of the substrate 42.
`In each of the embodiments of FIGS. 2a—2d, the curvature
`and contour of the cylindrical lens surfaces 34, 40 and 44
`define the macro-optical characteristic of the lens 30 or
`alternative lenses 37 and 41. The micro-structures 36 pro-
`vide the novel diffusing characteristics and are again molded
`or formed integral into a surface of the substrate bodies 32,
`38 and 42 along with the micro-optical characteristics for
`
`7
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`
`

`

`US 6,483,976 B2
`
`7
`each particular embodiment. Therefore, each of the lenses
`30, 37 or 41 are again monolithic structures. Importantly, the
`monolithic nature of the optical elements yields the highly
`desirable light diffusing and shaping advantages without the
`attendant Fresnel losses in prior art laminated structures. In
`fact, the monolithic optical elements of the present invention
`actually and unexpectedly increase light transmission.
`FIGS. 3a and 36 illustrate an optical element in the form
`of a parabolic convex lens 50. The lens 50 includes a
`substrate body 52 having on one side a curved or parabolic
`convex lens surface 54 and the plurality of micro-structures
`56 formed on the opposite side of the substrate body 52. The
`parabolic convexlens surface 54 produces the macro-optical
`characteristic of the lens 50 and the micro-structures 56
`provide the diffusing characteristics according to the present
`invention. Again,
`transmission efficiency is actually
`increased over laminated structures because the lens 50 is
`
`formed as a monolithic structure wherein the parabolic
`convex surface 54 and the micro-structures 56 are formed
`
`integral as a part of the substrate body material.
`Microstructures 56 may also be made nonuniform across
`the lens 50 to minimize certain lens aberrations. For
`example, as indicated by the arrows in FIG. 3 the micro-
`structures 56 at the outer edges of the lens may be designed
`to shape the light
`into a narrow distribution while the
`microstructures 56 in the middle may provide a broader light
`distribution pattern.
`FIGS. 4a and 4b illustrate an optical element in the form
`of a fiber optic cable 60 in an enlarged form. The cable 60
`includes a longitudinal substrate body 62, a core 62 and an
`external cladding 64 surrounding the core. The fiber optic
`element or cable 60 also has a distal end 66 at which the
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`cable terminates. The refractive index ofthe fiber optic cable
`partially defines the macro-optical light propagating char-
`acteristics of the cable.
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`8
`whereby the polarizers are embeddedin a substrate body 82.
`The substrate body 82 has the micro-structures 84 on one
`surface of the substrate. The opposite surface of the substrate
`is essentially flat in this embodiment because the polarizing
`capability of the substrate 82 is within the monolithic body
`itself. The optical element in the form of a polarizer 80 has
`formed in one surface a plurality of light diffusing or
`homogenizing micro-structures which provide the enhanced
`transmission and diffusing capabilities of the element.
`FIGS. 7a and 7b illustrate an optical element in the form
`of an opticalfilter grating structure 90. The grating structure
`90 includes a substrate body 92 and plurality of gratings 94
`formed therein by one of many known means. The grating
`structures are spaced apart periodic lines formed in the
`substrate material 92 which filter out certain wavelengths
`from the light source asit passes throughorreflects off of the
`structure 90. A plurality of the micro-structures 96 are
`formed into a surface of the grating structure 90 in the
`substrate body 92 during manufacture of the grating struc-
`ture. The optical element
`is a monolithic construction
`wherein the macro-optical gratings 94 and the micro-
`structures 96 are integral in the material of the substrate
`body 92.
`FIGS. 8a and 8billustrate an optical element in the form
`of a concave lens 100. The concave lens 100 includes a
`
`substrate body 102 having a concave surface 104 on oneside
`and the plurality of micro-structures 106 carried on the other
`side of the substrate. The curvature of the surface 104 and
`
`the refractive index defines the macro-optical characteristic
`of the lens 100 and the micro-structures 106 provide the
`diffusing or homogenizing characteristics of the lens 100.
`The curved surface 104 and the structures 106 are each
`
`integral into opposite sides of the materials of the substrate
`body 102.
`FIG. 9 illustrates a simple schematic view of another type
`of optical element in the form ofa total internal reflection or
`TIR lens assembly 110. The lens assembly 110 includes a
`TIR lens 112 which has on oneside a reflector surface 114
`for reflecting light entering the lens 112 back toward the
`direction from which it came at a predetermined angle. In
`this embodiment, the TIR lens 112 also includes a curved
`entrance surface 116 which permits light to pass initially
`therethrough into the lens but then reflects light back toward
`the interior of the lens once the light is inside of the lens
`itself as illustrated in FIG. 9. The curvature of the surface
`
`116 is determined by the angle of light entering the lens 112
`and the characteristics of the material from which the lens
`
`In this embodiment, the plurality of micro-structures 68
`are integrally formed on the end 66 of the cable 60 during
`formation of the cable. For example, during conventional
`manufacturing of a fiber optic cable, the cable substrate 62
`is formed in continuous lengths which are eventually cut to
`size. Once cut, the end may already be heated or can then be
`heated after separation from the continuous cable whereby
`the micro-structures 68 are then molded, embossed, or
`otherwise replicated in the end of the fiber optic cable 60. In
`this embodiment, the end of the fiber optic cable may be
`heated by any suitable meansas long as the materials of the
`core 62 and cladding 64 are elevated to a sufficient tem-
`perature in order that the micro-structures 68 are replicated
`into the material of the core 62. A monolithic structure is
`thus formed including the micro-structures 68 and the core
`62.
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`FIGS. 5a and 5b illustrate an optical element in the form
`of a prismatic structure 70. The structure 70 includes a
`substrate body 72 and a plurality of prism structures 74 on
`one side. The prism structures 74 may be in any configu-
`ration or construction including individual prismatic
`structures, a plurality of prism arrays, or merely a plurality
`of elongate prism structures formed on the substrate 72. A
`plurality of the micro-structures 76 are formed on the
`opposite side of the substrate 72. The substrate body 72, the
`macro-optical prism structures 74 and the diffuser micro-
`structures 76 are all formed integral
`in the monolithic
`prismatic structure 70.
`FIGS. 6a and 6b illustrate an optical element in the form
`of a polarizer 80 wherein the macro-optical characteristic is
`the filtering or polarizing property of the element and
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`112 is made as well as the reflector surface 114. A light
`source 118 is placed adjacent the lens 112 to direct light
`toward and into thelens.
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`50
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`In the embodiment illustrated in FIG. 9, the light source
`is a standard filament type incandescent light bulb which
`projects light
`in generally all directions and therefore
`requires a back reflector 120 for reflecting some of the light
`back towardsthe lens 112as illustrated in FIG. 9. The travel
`path of the light is indicated by the lines 122. A portion of
`the lens 112 is intended to permit the light to exit from the
`interior of the lens. In the present exemplary embodiment,
`light exits the opposed ends 124 of the lens 112. The
`microstructures 126 are formed on the surfaces 124 where
`the light exits the TIR lens 112 and is thus diffused and
`directed according to the design characteristics of the micro-
`structures 126. Such a TIR lens may take on any numberof
`configurations and constructions and is utilized in many
`different applications. Thus, the exit surfaces of the lens may
`vary greatly from the simple schematic illustrated in FIG. 9.
`However, the diffuser micro-structures 126 are formed inte-
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`US 6,483,976 B2
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`9
`gral with the material of the TIR lens 112 on each intended
`exit surface as desired.
`
`Such a TIR lens assembly 110 is found in many types of
`applications. These may include automotive lighting sys-
`tems including taillight assemblies, global positioning
`systems(G