Source: http://www.google.com/patents/US5543958
Timestamp: 2016-05-31 10:59:39
Document Index: 314842528

Matched Legal Cases: ['arts 47', 'art 47', 'arts 47', 'arts 47', 'arts 47', 'arts 47']

Patent US5543958 - Integrated electro-optic package for reflective spatial light modulators - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inPatentsAn array of reflective liquid crystal spatial light modulator pixels is formed on a substrate with a light polarizing layer positioned in overlying relationship to the array. An optical waveguide is positioned adjacent the polarizing layer and has a light source mounted adjacent an end thereof so that...http://www.google.com/patents/US5543958?utm_source=gb-gplus-sharePatent US5543958 - Integrated electro-optic package for reflective spatial light modulatorsAdvanced Patent SearchPublication numberUS5543958 APublication typeGrantApplication numberUS 08/360,504Publication dateAug 6, 1996Filing dateDec 21, 1994Priority dateDec 21, 1994Fee statusLapsedPublication number08360504, 360504, US 5543958 A, US 5543958A, US-A-5543958, US5543958 A, US5543958AInventorsMichael S. Lebby, George R. Kelly, Karen E. JachimowiczOriginal AssigneeMotorolaExport CitationBiBTeX, EndNote, RefManPatent Citations (4), Referenced by (39), Classifications (11), Legal Events (5) External Links: USPTO, USPTO Assignment, EspacenetIntegrated electro-optic package for reflective spatial light modulators
US 5543958 AAbstract
An array of reflective liquid crystal spatial light modulator pixels is formed on a substrate with a light polarizing layer positioned in overlying relationship to the array. An optical waveguide is positioned adjacent the polarizing layer and has a light source mounted adjacent an end thereof so that light is directed into the optical waveguide and further has a plurality of diffraction gratings formed therein so that deflected light evenly illuminates the array and allows passage of reflected light from the array back through the waveguide. Electrical connections are made from the array, through leads in the waveguide and to external contacts. A diffuser is mounted in overlying and spaced relationship to the waveguide to form an image plane for reflected light from the array.
1. An integrated electro-optic package for reflective spatial light modulators comprising:an array of reflective spatial light modulator pixels formed on a substrate with each pixel including a control circuit formed in the substrate, each control circuit including control terminals adjacent an outer edge of the substrate, a mirror positioned on the substrate in overlying relationship to the control circuit, and a layer of spatial light modulator material positioned in overlying relationship to the mirror so that light passing through the spatial light modulator material is reflected back through the spatial light modulator material; a light polarizing layer positioned in overlying relationship to the array of reflective spatial light modulator pixels; an optical waveguide having a light source mounted adjacent an end of the optical waveguide so that light from the light source is directed into the optical waveguide, the optical waveguide further having a plurality of elements spaced therealong for deflecting portions of the light from the light source out of the optical waveguide, and the optical waveguide being mounted in spaced relation from the array of reflective spatial light modulator pixels so that the deflected portions of the light from the light source substantially evenly illuminates the array of reflective spatial light modulator pixels and allows passage of reflected light from the array of reflective spatial light modulator pixels; and a diffuser mounted in overlying relationship to the optical waveguide to form an image plane for reflected light from the array of reflective spatial light modulators pixels. 2. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 1 wherein the optical waveguide is formed in an optically clear support constructed with a cavity formed to receive the array of reflective spatial light modulator pixels and the light polarizing layer therein and including electrical leads positioned to contact the control terminals adjacent an outer edge of the substrate.
4. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 3 wherein the optically clear support is formed of molded optically clear plastic.
5. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 4 wherein the molded optically clear support includes at least a cladding layer with a first index of refraction, the cladding layer having a groove formed therein filled with an optically clear plastic with an index of refraction at least 0.01 greater than the first index of refraction to define a core of the optical waveguide.
6. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 1 wherein the light source includes a plurality of light emitting diodes.
7. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 6 wherein the plurality of light emitting diodes includes at least two light emitting diodes, each of which emits a different color of light.
8. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 4 wherein the molded optically clear support includes a planar surface opposite the cavity and the planar surface has a plurality of lens fittings molded therein, the diffuser further includes a plurality of matching lens fittings positioned in the lens fittings of the planar surface so as to removeably position the diffuser in substantially parallel abutting engagement with the planar surface.
9. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 1 where, in the array of reflective spatial light modulator pixels, the layer of spatial light modulator material is a continuous layer across the entire array and each control circuit for each pixel formed in the substrate includes one contact, the array further including an optically clear contact positioned on an opposite side of the continuous layer with the one contact and the optically clear contact defining a pixel within the continuous layer.
10. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 9 wherein the optically clear contact for each pixel is formed in a layer if indium-tin-oxide deposited in overlying relationship to the continuous layer of spatial light modulator material.
11. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 9 wherein the mirror positioned on the substrate is a polished pad of metal, one for each pixel, which pad of metal also forms the one contact included in the control circuit.
12. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 11 wherein the polished pad of metal for each pixel is a polished pad of aluminum.
13. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 1 wherein each of the elements of the plurality of elements spaced along the waveguide include a diffraction grating.
14. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 13 wherein each diffraction grating is constructed to deflect out of the optical waveguide different amounts of the light from the light source.
15. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 1 including in addition a housing having leads formed therein so as to be in electrical contact with the control terminals adjacent an outer edge of the substrate of each control circuit and the leads further extend to an external portion of the housing to form external contacts for the control circuits.
16. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 14 wherein the housing is molded and the leads are a leadframe molded into the housing.
17. An integrated electro-optic package for reflective liquid crystal spatial light modulators comprising:a reflective liquid crystal spatial light modulator stack including a substrate with a plurality of control circuits formed therein, each control circuit including control terminals adjacent an outer edge of the substrate and an electrical contact mirror positioned on the substrate, each electrical contact mirror defining a pixel and a first electrical contact for the pixel, a layer of liquid crystal spatial light modulator material positioned in overlying relationship to the electrical contact mirrors so that light passing through the liquid crystal spatial light modulator material is reflected back through the spatial light modulator material, and an electrically conductive optically transparent layer of material positioned on an opposite surface of the liquid crystal spatial light modulator material to form a second electrical contact for each pixel; a light polarizing layer positioned in overlying relationship to the electrically conductive optically transparent layer of material; an optical waveguide having a light source mounted adjacent an end of the optical waveguide so that light from the light source is directed into the optical waveguide, the optical waveguide further having a plurality of diffraction gratings spaced therealong for deflecting portions of the light from the light source out of the optical waveguide, and the optical waveguide being mounted in spaced relation from the array of reflective liquid crystal spatial light modulator pixels so that the deflected portions of the light from the light source substantially evenly illuminates the array of reflective liquid crystal spatial light modulator pixels and allows passage of reflected light from the array of reflective liquid crystal spatial light modulator pixels; and a diffuser mounted in overlying and spaced relationship to the optical waveguide to form an image plane for reflected light from the reflective liquid crystal spatial light modulator stack. 18. An integrated electro-optic package for reflective liquid crystal spatial light modulators as claimed in claim 17 wherein the layer of liquid crystal spatial light modulator material is contained within a closed cavity having internal opposed flat surfaces, the electrical contact mirrors are affixed to one of the internal surfaces and the electrically conductive optically transparent layer is affixed to the other of the internal surfaces.
20. An integrated electro-optic package for reflective liquid crystal spatial light modulators comprising:a reflective liquid crystal spatial light modulator stack includinga substrate with a plurality of control circuits formed therein, each control circuit including control terminals adjacent an outer edge of the substrate and an electrical contact mirror positioned on the substrate, each electrical contact mirror defining a pixel and a first electrical contact for the pixel, a layer of liquid crystal spatial light modulator material positioned in overlying relationship to the electrical contact mirrors so that light passing through the liquid crystal spatial light modulator material is reflected back through the liquid crystal spatial light modulator material, an electrically conductive optically transparent layer of material positioned on an opposite surface of the liquid crystal spatial light modulator material to form a second electrical contact for each pixel, and the layer of liquid crystal spatial light modulator material being contained within a closed cavity having internal opposed flat surfaces and defined by a surface of the substrate, a spacer affixed to the surface of the substrate and a glass plate affixed over the spacer with the electrical contact mirrors affixed to one of the internal surfaces and the electrically conductive optically transparent layer affixed to the other of the internal surfaces; an optically clear support having defined therein a cavity formed to receive the reflective liquid crystal spatial light modulator stack in nesting engagement, the optically clear support further including a plurality of electrical leads each formed therein so as to provide a first contact in the cavity and a second contact at an external surface of the optically clear support; the optically clear support further including an optical waveguide formed therein and having a light source mounted adjacent an end of the optical waveguide so that light from the light source is directed into the optical waveguide, the optical waveguide further having a plurality of diffraction gratings spaced therealong for deflecting portions of the light from the light source out of the optical waveguide, and the optical waveguide being positioned in the optically clear support in spaced relation from the array of reflective liquid crystal spatial light modulator pixels so that the deflected portions of the light from the light source substantially evenly illuminates the array of reflective liquid crystal spatial light modulator pixels and allows passage of reflected light from the array of reflective liquid crystal spatial light modulator pixels through the optically clear support; and a light polarizing layer positioned in the cavity of the optically clear support; the reflective liquid crystal spatial light modulator stack being nestingly positioned in the cavity so that the polarizing layer is positioned in overlying relationship to the electrically conductive optically transparent layer of material and so that the deflected portions of the light from the light source and reflected light from the array of reflective liquid crystal spatial light modulator pixels pass through the polarizing layer, the reflective liquid crystal spatial light modulator stack being further positioned in the cavity so that the control terminals adjacent an outer edge of the substrate are in contact with the plurality of electrical leads formed in the optically clear support; and a diffuser mounted in overlying relationship to the optically clear support to receive reflected light from the reflective liquid crystal spatial light modulator stack. 21. A method of fabricating an integrated electro-optic package for reflective liquid crystal spatial light modulator comprising the steps of:providing a stack including a plurality of reflective liquid crystal spatial light modulators formed in a two dimensional array on a semiconductor substrate with drive electronics formed in the substrate for each liquid crystal spatial light modulator of the array of liquid crystal spatial light modulators and control terminals for the drive electronics positioned adjacent outer edges of the substrate, the stack further including a light transparent surface defining a light input and light output for each of the liquid crystal spatial light modulators in the two dimensional array of reflective liquid crystal spatial light modulators; forming an optically clear support having an optical waveguide formed therein and mounting a light source adjacent an end of the optical waveguide so that light from the light source is directed into the optical waveguide, the optical waveguide further being formed with a plurality of diffraction gratings spaced therealong for deflecting portions of the light from the light source out of the optical waveguide, and the optical waveguide being positioned in the optically clear support in spaced relation from the array of reflective liquid crystal spatial light modulator pixels so that the deflected portions of the light from the light source substantially evenly illuminates the array of reflective liquid crystal spatial light modulator pixels and allows passage of reflected light from the array of reflective liquid crystal spatial light modulator pixels through the optically clear support, the optically clear support being further formed to define therein a cavity formed to receive the reflective liquid crystal spatial light modulator stack in nesting engagement therein with a lower surface of the cavity substantially parallel with and adjacent to the light transparent surface of the stack, and the optically clear support further being formed to include a plurality of electrical leads each positioned therein so as to provide a first contact in the cavity and a second, electrically coupled contact at an external surface of the optically clear support; providing a light polarizing layer and positioning the polarizing layer in the cavity of the optically clear support; positioning the stack nestingly in the cavity so that the polarizing layer is positioned in overlying relationship and adjacent to the light transparent surface of the stack so that deflected light from the optical waveguide passes through the polarizing layer, substantially evenly illuminating the light transparent surface of the stack, and reflected light from the light transparent surface of the stack passes through the polarizing layer and the optically clear support; and diffusing light reflected from the stack to form an image. 22. A method of fabricating an integrated electro-optic package for reflective liquid crystal spatial light modulators as claimed in claim 21 wherein the step of forming an optically clear support includes molding the optically clear support and the optical waveguide from plastic.
23. A method of fabricating an integrated electro-optic package for reflective liquid crystal spatial light modulators as claimed in claim 22 wherein the step of molding the optically clear support and the optical waveguide from plastic includes a step of molding a leadframe into the plastic to form the plurality of electrical leads.
24. A method of fabricating an integrated electro-optic package for reflective liquid crystal spatial light modulators as claimed in claim 23 wherein the step of molding the optically clear support and the optical waveguide from plastic includes forming the optically clear support with opposed edge surfaces and forming the optical waveguide to extend from one edge surface to the opposed edge surface, and the step of mounting a light source adjacent an end of the optical waveguide includes positioning the light source on the edge surfaces.
The above described problems and others are at least partially solved and the above purposes and others are realized in an integrated electro-optic package for reflective spatial light modulators including an array of reflective spatial light modulator pixels formed on a substrate with a light polarizing layer positioned in overlying relationship to the array and an optical waveguide positioned adjacent the polarizing layer and having a light source mounted adjacent an end thereof so that light is directed into the optical waveguide and further having a plurality of diffraction gratings formed therein so that deflected light substantially evenly illuminates the array and allows passage of reflected light from the array back through the waveguide. The package further includes a light polarizing layer positioned in overlying relationship to the array of reflective spatial light modulator pixels so that deflected light from the optical waveguide passes through the polarizing layer and reflected light from the array passes through the polarizing layer. Electrical connections are made from the array, through leads in the waveguide and to external contacts. A diffuser is mounted in overlying relationship to the waveguide to form an image plane for reflected light from the array.
The above described problems and others are at least partially solved and the above purposes and others are further realized in a method of fabricating an integrated electro-optic package for reflective spatial light modulators including providing an optically clear support by some convenient method, such as molding or the like. The optically clear support includes the optical waveguide with a light source mounted adjacent an end thereof. The polarizing layer is positioned on one side of the optically clear support and the diffuser is positioned on an opposed side of the optically clear support to provide an image. Also, electrical leads are positioned in the optically clear support to connect to the reflective spatial light modulators and provide an external electrical connection thereto.
FIG. 4 is a perspective view of the reflective liquid crystal spatial light modulator stack illustrated in FIG. 3, mounted on a driver board;
FIG. 5 is a simplified schematic view generally illustrating dual image manifestation apparatus utilizing two of the integrated electro-optic packages illustrated in FIG. 4;
FIG. 6 is a perspective view of the dual image manifestation apparatus illustrated in FIG. 5; and
FIGS. 7, 8 and 9 illustrate a front view, side elevational view, and top plan, respectively, of image manifestation apparatus utilizing the integrated electro-optic package illustrated in FIGS. 3 and 4; and
FIG. 10 is a 4� magnified view in side elevation of the apparatus of FIG. 9.
A two dimensional array of reflective metal pads 15 are formed on the upper surface of substrate 11, which metal pads 15 each define a reflective LCSLM pixel. In the present embodiment, metal pads 15 are made of aluminum or any metal that can be conveniently patterned on the surface of substrate 11 and which will reflect light impinging thereon. Each metal pad of the plurality of metal pads 15 is electrically connected to a driver circuit and addressing and switching circuitry so as to form one contact for activating the liquid crystal material in the space above metal pad 15, forming a pixel.
Glass window 25 completes reflective LCSLM stack 10 which includes a two dimensional array of reflective liquid crystal pixel elements, each of which are individually addressable through bond pads 12. To turn a pixel ON a potential must be applied between the upper and lower contacts for that specific pixel. With no potential applied, the pixel is normally in an OFF condition. Glass plate 25 defines a light input and light output for each of the pixels in the two dimensional array of reflective LCSLM pixels. While the present embodiment is explained using liquid crystal material in the pixels, it should be understood that other types of spatial light modulators might be utilized in the pixels, including, for example, other types of light modulating liquid or solid material, mirrors or other reflective material, etc.
Referring now to FIG. 3, an enlarged sectional view of an integrated electro-optic package 40 embodying the present invention is illustrated. Package 40 includes reflective spatial light modulator stack 10, which is illustrated in an even more simplified form for convenience. An optically clear support 41 having a cavity 42 formed therein is fabricated by any convenient means, such as molding, etching, or the like. As an example of a preferred embodiment, support 41 is molded using any convenient optically clear plastic, such as optically clear liquid epoxy available under a Tradename EPO-TEK 301-2 from EPOXY TECHNOLOGY INC. or a clear epoxy molding compound available under the Tradename HYSOL MG18 from Dexter Corporation. In the preferred embodiment, support 41 is formed of plastic with a relatively low coefficient of expansion (e.g. 20 ppm or less) so that support 41, substrate 11, glass spacer 20 and glass window 25 all have a temperature coefficient of expansion within a range that allows reasonable temperature cycling of the structure without causing critical or damaging stresses.
One or more optical waveguides 46 are formed in optically clear support 41 by any convenient method. As an example, support 41 (or only the portion thereof defining waveguide 46) can be formed by molding two mating parts 47 and 48 with a groove defining the core 49 of waveguide 46 molded in one part 47 or 48 so as to be positioned between the two mating parts 47 and 48. In this specific example parts 47 and 48 are molded from the clear epoxy molding compound available under the Tradename HYSOL MG18 from Dexter Corporation. Parts 47 and 48 are then bonded together and, simultaneously, the groove is filled, to form core 49 of waveguide 46, with an optically clear adhesive liquid, such as the optically clear liquid epoxy available under the Tradename EPO-TEK 301-2 from EPOXY TECHNOLOGY INC. Parts 47 and 48 form cladding layers surrounding core 49 of waveguide 46 and generally have an index of refraction which is approximately and at least 0.01 less than the index of refraction of the core material.
Additional information for methods of constructing optical waveguides in this fashion is available in U.S. Pat. No. 5,345,530, issued Sep. 6, 1994, and entitled "Molded Waveguide and Method for Making Same". Other optical waveguides, which might be utilized in integrated electro-optic package 40, and methods of fabrication are disclosed in U.S. Pat. No. 5,313,545, issued May 17, 1994, and entitled "Molded Waveguide with a Unitary Cladding Region and Method of Making".
In the specific embodiment illustrated in FIG. 3, optical waveguide 46 extends from one side of optically clear support 41 to an opposing side. The exposed ends are polished or otherwise adapted for the introduction of light thereto. A light source 52 is mounted at each end of core 49 of waveguide 46 so that light from light source 52 is directed into core 49. While a light source 52 is illustrated at each end of core 49 in this embodiment, it will be understood that only one end could extend to an edge of optically clear support 41 and a single light source could be used to direct light thereinto. Also, it should be understood that a plurality of either the double or single light source types of waveguides can be utilized in optically clear support 41 to ensure substantially even illumination of the array of reflective spatial light modulator pixels, as will be explained in more detail presently.
Optical waveguide 46 includes a plurality of elements 50 spaced therealong for deflecting portions of the light from light sources 52 out of optical waveguide 46, generally upwardly in FIG. 3, and onto polarized 45. Elements 50 are any optical element that will deflect or redirect a portion of the light emanating from light sources 52, such as diffraction gratings, two way mirrors, or partial reflectors positioned in core 49, or diffraction gratings positioned adjacent core 49. Optical waveguide 46 is formed in optically clear support 41 in spaced relation from the array of reflective spatial light modulator pixels in stack 10 so that the deflected portions of the light from light sources 52 substantially evenly illuminate the array of reflective spatial light modulator pixels and allow passage of reflected light from the array of reflective spatial light modulator pixels.
An example of I/O nodes formed with optical waveguides by using holographic gratings is disclosed in U.S. Pat. No. 5,335,300, issued Aug. 2, 1994 and entitled "Method of Manufacturing I/O Nodes in an Optical Channel Waveguide and Apparatus for Utilizing". The I/O nodes described in this patent deflect a portion of light passing through the optical waveguide out of the waveguide and could be utilized in conjunction with core 49. It should be understood that each element 50 is generally constructed to deflect or redirect a larger percentage of the light out of core 49 the farther into core 49 the light travels. This is generally required to provide uniform illumination of stack 10, because as light progresses down core 49 each element 50 deflects a portion of the light so that there is less light in core 49 subsequent to each element 50.
Each light source 52 can include a single light emitting diode (LED) or several diodes positioned to operate as a single source. For example, currently known GaN LEDs are capable of producing output power of approximately 40 mA and 2 mW, which translates into an output power of approximately 11 lumens/watt. Also, three LEDs (a red, a green and a blue LED) can be provided as a single light source 52 at the end or ends of waveguide 46 or at the ends of three different but adjacent waveguides 46. In such an embodiment the three different colored LEDs are alternately activated to form three different light sources 52, each of which fully and uniformly illuminates stack 10 at different times. By activating each LCD in stack 10 in accordance with the amount of each color (red, green, or blue) required in each pixel during the time that that color LED is activated, a complete and full color image is produced for each cycle of the three LEDs. It will of course be understood that more than one LED of each color can be utilized if more than one is required to provide full and uniform illumination.
In this specific embodiment, electrical traces or leads 55 are provided on the surface of the edges of optically clear support 41 during the molding process and extend upwardly into electrical contact with a plurality of upwardly extending mounting pins 60. Light sources 52 are bump bonded to traces or leads 55 during the assembly process and, therefore, some of pins 60 are utilized to supply an activating voltage to light sources 52. Also, a plurality of generally L-shaped leads 61 are formed in support 41 so as to electrically engage bond pads 12 of substrate 11 at one end thereof and so that the other end engages some of pins 60 and forms external electrical terminals for the contacts formed in transparent electrically conductive material 24 and the driver circuits formed in substrate 11.
Optically clear support 41 has a generally planar lower surface 65 opposite cavity 42. Surface 65 has a plurality of lens fittings 71 formed therein, which in this specific embodiment are generally dovetailed openings or grooves. A diffuser 72, which in this embodiment is a generally disk-shaped lens, is formed with matching lens fittings 73 positioned on an upper surface thereof. Generally, for convenience lens fittings 71 are molded simultaneously with optically clear support 41 or they may be formed later by cutting, etching, etc. Also, diffuser 72 may be formed by molding optical quality plastic and matching lens fittings 73 can be molded therein simultaneously. Diffuser 72 is then mounted on optically clear support 41 by simply engaging matching lens fittings 73 in lens fittings 71 and sliding diffuser 72 into overlying relationship with planar surface 65 of optically clear support 41. Thus, diffuser 72 is removeably positioned in substantially parallel abutting engagement with planar surface 65 and forms an image plane for light emitted from stack 10.
It will be understood that diffuser 72 can be mounted adjacent surface 65 by any of a variety of other apparatus including, for example, forming diffuser 72 as an optical lens which is removeably and/or adjustably mounted in a cavity formed in the lower surface of optically clear support 41 (not shown). In such an embodiment, diffuser 72 can be formed in the shape of a disk with external threads on the outer periphery thereof, which threads are threadidly engaged in internal threads on the inner surface of the cavity. Thus, diffuser 72 can be easily and quickly moved axially relative to stack 10 to provide focusing of the image formed on diffuser 72. It should be understood that the diffusion required to produce a real image from the light reflected by the array of LCSLMs can be provided by a diffusion element (not shown) positioned between polarizing plate 45 and core 49, or, in some applications, by a diffusion material positioned on the surfaces of metal plates 15, or some combination of the above.
If a cavity is provided in surface 65 of optically clear support 41, the cavity may be further formed to receive, before or after receiving the diffuser, single or multiple optical elements therein, such as refractive or diffractive lenses, diffusers, filters, etc. Also, such optical elements can be added to diffuser 72 in FIG. 3. The additional optical elements can be formed separately from diffuser 72 or as a single unit with diffuser 72. Also, it will be understood that diffuser 72 and/or extra optical elements can be mounted in a cavity in surface 65 by threaded engagement (as illustrated) or by any other convenient means, such as "snap-in" or frictional engagement.
To complete integrated electro-optic package 40, any encapsulation that is required and/or desirable can now be performed. For example, light sources 52 are encapsulated or glob-topped with a plastic material 90 (see especially FIG. 3) and, similarly, integrated circuits 82 are encapsulated or glob topped. Also, in some instances it may be desirable to place a layer of insulating plastic over substrate 11 to ensure complete separation from other leads and the like.
Referring specifically to FIG. 4, a perspective view of integrated electro-optic package 40, mounted on a driver board 80, is illustrated. A plurality of driver and switching circuits and data processing circuits are fabricated in integrated circuits 82 and mounted on the upper surface of driver board 80 by any convenient method, such as bump bonding, wire bonding, direct mounting, etc. Electrical traces or wires are formed in driver board 80 and extend from the various pins or terminals of integrated circuits 82 into electrical contact with pins 60 of integrated electro-optic package 40. Driver board 80 can be constructed of any convenient material, such as printed circuit board, FR4, glass, ceramic, etc. Again, integrated electro-optic package 40 can be mounted on driver board 80 by any convenient method, such as simply plugging pins 60 into a matching receptacle, bump bonding, etc.
Image generator 115 includes, for example, integrated electro-optic package 40 (as illustrated in FIG. 4) mounted on a printed circuit board 80 and driven by data processing circuits 82, also mounted on printed circuit board 80. Data processing circuits 82 include, for example, logic and switching circuit arrays for controlling each pixel in the SLM array of image generator 115. Data processing circuits 82 include, in addition to or instead of the logic and switching arrays, a microprocessor or similar circuitry for processing input signals to produce a desired real image on the diffuser of image generator 115.
In this specific embodiment the pixels are formed in a regular, addressable pattern of rows and columns and, by addressing specific pixels by row and column in a well known manner, the specific pixels are activated to produce a real image on the diffuser. Digital or analog data is received at an input terminal and converted by data processing circuits 82 into signals capable of activating selected pixels to generate the predetermined real image.
Here it should be understood that the virtual image viewed by the operator through lens system 117 is relatively large (e.g. 8.5"�11") and appears to the operator to be several feet behind dual image manifestation apparatus 100. Because of the size of the virtual image produced by image manifestation apparatus 112, a large variety of alpha-numeric and/or graphic images can be easily and conveniently viewed. Further, image manifestation apparatus 112 is very small and compact so that it can easily be incorporated into portable electronic devices, such as pagers, two-way radios, cellular telephones, data banks, etc., without substantially effecting the size or power requirements.
Second image manifestation apparatus 114 constructed to provide a direct view image includes an image generator 120, which includes integrated electro-optic package 40 (as illustrated in FIG. 3) similar to image generator 115, an optical waveguide 122 an optical element 124 and a direct view screen 125. Image generator 120 is mounted in overlying relationship on an optical input to optical waveguide 122. The image from image generator 120 is reflected and/or otherwise directed by an optical element 121 onto optical element 124. While element 124 is illustrated as a separate element, it will be understood that it could be incorporated as a portion of optical waveguide 122. Optical element 124 can also include a Fresnel lens, or the like, for focusing and/or magnification if desired. The image from optical element 124 is directed onto screen 125 where it can be directly viewed by the operator.
FIGS. 7, 8 and 9 illustrate a front view, side elevational view, and top plan, respectively, of another miniature virtual image display 150 in accordance with the present invention. FIGS. 7, 8 and 9 illustrate miniature virtual image display approximately the actual size to provide some indication as to the extent of the reduction in size achieved by the present invention. Display 150 includes an integrated electro-optic package 155 which includes, in this specific embodiment, 144 pixels by 240 pixels. Each pixel is fabricated approximately 20 microns on a side with a center-to-center spacing between adjacent diodes of no more than 20 microns. In a preferred embodiment, integrated electro-optic package 155 produces a luminance less than approximately 15 fL. This very low luminance is possible because display 150 produces a virtual image. Further, because a very low luminance is required, LEDs and the like may be utilized as the light source for the SLM stack, which greatly reduces the size and power requirements. Integrated electro-optic package 155 is mounted on the surface of a driver board 158. An optical system 165 is also mounted on driver board 158 and magnifies the image approximately 20� to produce a virtual image approximately the size of an 8.5"�11" sheet of paper.
Referring specifically to FIG. 10, a 4� magnified view in side elevation of miniature virtual image display 150 of FIG. 8 is illustrated for clarity. From this view it can be seen that a first optical lens 167 is affixed directly to the upper surface of integrated electro-optical package 155. An optical prism 170 is mounted to reflect the image from a surface 171 and from there through a refractive surface 172. The image is then directed to an optical lens 175 having a refractive inlet surface 176 and a refractive outlet surface 177. From lens 175 the image is directed to an optical lens 180 having an inlet refractive surface 181 and an outlet refractive surface 182. Also, in this embodiment at least one diffractive optical element is provided on one of the surfaces, e.g. surface 171 and/or surface 176, to correct for aberration and the like. The operator looks into surface 182 of lens 180 and sees a large, easily discernible virtual image which appears to be behind display 150.
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