JP2009511996A - Apparatus and method for optical resizing and backlighting - Google Patents

Abstract

A backlight assembly for providing illumination light to a passive display panel having a plurality of pixel regions each defined by at least two subpixel positions each corresponding to at least two color channels characterizing the pixel region The backlight assembly includes a plurality of waveguides, which are formed and / or embedded in one or more substrates, and wherein the illumination light is illuminated in such a way that each pixel region is illuminated by at least two waveguides. For each sub-pixel location, each waveguide of the at least two waveguides being arranged to illuminate one sub-pixel location of the pixel region by a respective color channel.
[Selection] Figure 7b

Description

  The present invention relates to optics, and more particularly to an apparatus and method for optical resizing or backlighting.

  The miniaturization of electronic devices has always been a permanent goal in the field of electronic equipment. Electronic devices often include some form of display that is visible to the user. As these devices are reduced in size, their displays are also reduced in size. However, beyond a certain size, the display of the electronic device cannot be viewed with the naked eye and the image must be magnified.

  The electronic display can provide a real image whose size is determined by the physical size of the display device, or a virtual image whose size can exceed the dimensions of the display device.

  The magnification of the image produced by the small image display system can be performed by projecting the image onto a larger screen or via a passive optical magnification element that provides the user with a magnified virtual image. A virtual image is defined as an image that cannot be projected onto a display surface because the image and the observer are not connected by light rays.

  However, it is recognized that the above enlargement technique is not ideal. The projected real image has a bulky problem because the image enlargement is achieved by light propagation perpendicular to the display during projection. An apparatus for generating a virtual image has a limited field of view and is often bulky.

  In another magnification technique, the image is not projected but rather guided in a bundle of optical fibers that extend from a small facet to a large facet. Small facets are often referred to as “object planes”, while larger facets are often referred to as “image planes”.

  Referring now to the drawings, FIGS. 1-2 are schematic illustrations of several prior art techniques for manufacturing a fiber-based guidance magnifier.

  FIG. 1a shows an optical image transport apparatus based on the teachings of US Pat. No. 2,825,260. Expansion from a small facet to a large facet is achieved by increasing the separation between the fibers in the bundle. FIG. 1b shows a variation of this method disclosed in US Pat. Nos. 2,992,587 and 3,853,658. In this technique, the fiber is uptapered toward a large facet. However, these techniques were not able to be produced due to technical limitations associated with optical fiber separation and uptapering.

  An attempt to overcome the uptapering problem is disclosed in US Pat. No. 3,909,109, where an additional layer is added to the large facet. The layer thickness is chosen to allow free propagation in the layer until the far field beams of the fibers overlap. However, this technique is subject to great limitations because the Gaussian far-field line makes it difficult to determine the optimum thickness of the additional layer.

  FIG. 1c shows another improvement of the apparatus of FIG. 1a based on the teachings of US Pat. Nos. 3,439,910 and 4,280,096. In this refinement, fiber separation is performed in only one dimension, so that other (substantially perpendicular) dimensions are separated by terraces or bevels. In this configuration, the fibers are separated in one direction and then redirected towards a large facet, where they are cut stepwise or diagonally to separate in a substantially perpendicular direction. A major limitation of this solution is the difficulty of manufacturing.

  FIGS. 2a-b illustrate another technique for producing an optical fiber magnifying element in accordance with the teachings of U.S. Pat. Nos. 3,340,000 and 6,326,939. Referring to FIG. 2a, the one-dimensional magnification element includes a cylindrical optical fiber cut so that a circular cross section is formed on one side and an elliptical cross section is formed on the opposite side. The circular cross section is perpendicular to the longitudinal axis of the cylinder and thus has the same diameter as the cylinder. The elliptical cross section is beveled with respect to the longitudinal axis and thus has a minor axis equal to the diameter of the cylinder and a major axis longer than the diameter of the cylinder. When light passes through the fiber from the circular side to the elliptical side, a one-dimensional expansion is established in the direction of the major axis of the elliptical cross section.

  Referring to FIG. 2b, two such one-dimensional enlargement elements are connected via a redirecting layer so that the output of one element is used as the input of another element. A second redirecting layer is used to couple light from the second magnification element. In order to achieve proper optical coupling between the first and second elements, the cross section of the fiber on the input side of the second element must have the same elliptical cross section as the fiber on the output side of the first element.

  However, since the fiber input cross section must be perpendicular to their longitudinal axis, the elliptical input cross section of the second element fiber cannot be obtained by oblique cutting. On the other hand, there is no fiber bundle of elliptical fibers. Therefore, in order not to reduce the resolution with the second magnification, the number of fibers in the second element must be greater than the number of fibers in the first element by a factor equal to the one-dimensional magnification of the first element. Further disadvantages of this technique are the need for a redirecting layer and the presence of non-stimulated light, which can reduce the aspect ratio of the display.

  U.S. Pat. Nos. 5,511,141 and 5,500,071 disclose a reading magnifier formed by a bundle of juxtaposed and longitudinally tapered optical fibers. The magnifying device is a product of Taper Coag. Ltd .. [E. Peli, W.W. P. Siegmund, “Fiber-optic reading for the implied implied”, J Opt Soc Am A 12 (10): 2274-2285, 1995]. However, TapeMag ™ is bulky (thickness of about 5 cm just double it on a 2 inch screen) because its thickness must be equal to the size of the facet diameter.

  Kawashima et al., U.S. Pat. No. 6,480,345, discloses an enlargement device that utilizes a high index region extending from a small facet to a large facet. Simulations performed by Kawashima et al. Revealed that a 30-inch magnifier has a thickness of less than 4 cm and can perform 10-fold magnification. However, the manufacturing process of Kawashima's expansion device is rather complex. For example, one embodiment of Kawashima et al. Includes an alignment of dozens of laminated sheets produced by a mask with increasing core dimensions. Another embodiment of Kawashima et al. Includes three-dimensional fiber processing. Kawashima et al. Also teach a simpler manufacturing process, but these are limited to a magnification of 2 times or less.

  In addition to enlarging displayed images, efforts have been made over the years to research and develop display technologies to improve image quality while reducing the power consumption and bulk of display devices.

  In general, electronic display devices can be classified into active display devices and passive display devices. The active display device includes a cathode ray tube (CRT), a plasma display panel (PDP), and an electroluminescent display (ELD). Passive display devices include liquid crystal displays (LCD), electrochemical displays (ECD) and electrophoretic image displays (EPID). In an active display device, each pixel emits light independently. On the other hand, passive display devices do not produce light within the pixel, and the pixel can only block light.

  Among the above display technologies, passive display devices, particularly LCD devices, have become advanced technologies due to their proven high quality and small form factor (slimness). LCD devices are currently used in many applications (cell phones, personal acceptance devices, desktop monitors, portable computers, television displays, etc.) and a high quality set of backlights to improve image quality in these applications. Consideration for considering solid objects is increasing.

  In an LCD display, an electric field is applied to the liquid crystal module, and the arrangement of liquid crystal molecules is changed depending on the electric field, thereby changing the optical properties of the liquid crystal such as birefringence, optical rotation, dichroism, and light scattering. Since LCDs are passive, they use light emitted by reflecting external light transmitted through the LCD panel or from a light source (eg, a backlight assembly) located behind the LCD panel. To display the image.

  Backlight assembly to achieve many purposes including high brightness, large area coverage, uniform brightness across the illuminated area, controlled viewing angle, small thickness, low weight, low power consumption and low cost Designed.

  FIG. 42a shows a typical LCD device. The apparatus includes an LCD panel and a backlight assembly. An LCD panel includes an array of LCD pixels, which are typically formed from thin film transistors made on a transparent substrate, with a liquid crystal and a color filter sandwiched between them. A color filter made on another transparent substrate generates color light by transmitting only one third of the light generated by each pixel. Therefore, each LCD pixel is composed of three subpixels. The thin film transistor is addressed by a gate line to perform a display operation by a signal applied through the display signal line. The signal charges the liquid crystal layer near each thin film transistor to effect a local change in the optical properties of the liquid crystal layer.

  In operation, the backlight assembly produces white illumination directed at the liquid crystal pixels. The optical properties of the liquid crystal layer are locally modulated by the thin film transistor, creating a light intensity modulation throughout the area of the display. In particular, static polarizers polarize the light generated by the backlight assembly, and liquid crystal pixels selectively manipulate the polarization of light passing through it. Light intensity modulation is achieved using a static polarizer positioned in front of the liquid crystal pixel that prevents transmission of light of a particular polarization. The color filter colors the intensity modulated light emitted by the pixel and produces a color output. By selective opacity modulation of adjacent pixels of the three color components, the selected intensities of the three component colors are mixed together to selectively control the color light output. A mixture of the three primary colors, such as red, green, and blue (RGB), can generally produce a full range of colors suitable for color display purposes.

  Traditionally, cold cathode fluorescent light (CCFL) has been used for LCD backlighting. The fluorescent lamp and the optical element are arranged to scatter light uniformly over the entire LCD panel, and the color filter is arranged to separate the colors. The diffusing layer and the reflector are respectively used to further homogenize the backlight spectrum and reduce light leakage. In order to ensure sufficient light transmission, a relatively broad spectrum color filter is used. However, this results in crosstalk between RGB pixels, which limits the available color gamut that can be obtained from CCFL backlighting. In addition, CCFL backlighting systems are expensive, bulky, consume power, and contain Hg.

  In more advanced technology, an LCD backlight assembly includes an array of light emitting diodes (LEDs) for emitting white or RGB light, a light guide plate for guiding light toward the LCD panel, and an LCD panel. It includes a diffusion layer positioned between the LEDs for uniformizing the backlight spectrum of the LCD panel. Often, a reflector is placed behind the light guide plate to reflect light leaking from the light guide plate towards the light guide plate. LEDs can improve the overall color gamut of LCDs due to their inherent narrow color spectrum. Furthermore, LEDs do not contain Hg, they give a high brightness to size ratio, have a long lifetime, and can be incorporated into a robust design. A key problem in introducing LEDs is to find an efficient way to spread the LED light uniformly across the backlighting panel. Such types of backlight assemblies are disclosed, for example, in US Pat. Nos. 6,608,614, 6,930,737, and US Patent Application Nos. 20040264911, 20050073495, 20050117320. However, this technique, like CCFL, has an inherent output loss of two-thirds of the total output due to the use of RGB filters in the LCD panel.

  FIG. 42b schematically illustrates another conventional backlighting technique designed to overcome the inherent output loss described above. In this technique, the colors are separated (instead of being filtered) by a prism located behind the LCD subpixel. Such types of backlight assemblies are disclosed, for example, in US Pat. Nos. 5,748,828 and 6,104,446 and references contained therein. However, this technique is subject to bulkiness and low efficiency due to the bulky optical elements involved.

  FIG. 42c schematically illustrates an additional conventional backlighting technique designed to overcome the inherent output loss. In this technique, as opposed to the technique described above, the colors are guided separately into their scheduled columns of subpixels rather than being mixed into white light. The red, green and blue LEDs are coupled to separate optical fibers. The optical fiber illuminates the position of the red, green and blue pixels of the LCD. The LED is always on and there is no color filter.

  Such types of backlight assemblies are disclosed, for example, in US Pat. No. 6,768,525 and in part in US Pat. Nos. 6,104,371 and 6,288,700. However, this technique is difficult to implement. Because it requires some fiber processing, it does not provide a solution to the problem of addressing RGB light transmitted to the color filter array without crosstalk.

  Furthermore, this technique only provides limited uniformity of light distribution. For example, in US Pat. No. 6,104,371 to Wang et al., Optical fibers are coupled to an RGB light source and arranged in a series of parallel rows within the panel. The uniformity of the output light is achieved by placing a vertically reflecting wedge that increases in height along the fiber, implementing increased reflection that compensates for the decrease in optical power along the fiber. However, Wang et al. Cannot provide light uniformity at the subpixel level. In addition, Wang et al. Uses a 3 × N fiber stack (N is a large number) so that all RGB colors are mixed in the output.

  In Mori US Pat. No. 6,288,700, a cylindrical waveguide coupled to an RGB source is divided into small parallel waveguides provided with holes for coupling light. The holes are arranged in an addressable arrangement. However, such a backlighting configuration results in poor performance due to the low efficiency characterized by the coupling of light exiting the waveguide through the hole. In addition, Mori guides all RGB colors in the same waveguide, so there is no color separation at the subpixel level. A further disadvantage of the Mori technique is the lack of light scattering or light distribution uniformity in parallel waveguides.

  In US Pat. No. 6,768,525 to Paolini et al., Fibers coupled to RGB light sources are placed in parallel in a continuous arrangement and scatter light along their length. The spacing between the scattering points along each fiber and the fiber can be matched to the spacing between the subpixels of the LCD panel. However, while coupling each color to a separate waveguide, Paolini et al. Provide no practical technique to achieve a sufficiently accurate placement where different colors reach different subpixels with minimal mixing. It has been recognized that the light coupling out of the waveguide is due to scattering, so crosstalk between adjacent colors cannot be avoided and the light uniformity at the sub-pixel level for each color is limited. ing. Also disclose a configuration in which one layer of parallel fibers is replaced one for each color by three layers of parallel bulky diffusion waveguides. The diffusion waveguide is made of scattering notches. The spacing between the scattering notches can match the space between the pixels, and the space between the bulky waveguides can match the space between the subpixels.

  However, since the parallel diffusion waveguides of Paolini et al. Must have large aspect ratios (narrower than their thickness) and are separated from each other, such a configuration has very poor efficiency and uniformity. The reason is that it is difficult to make such a waveguide with a large aspect ratio, so many diffusion waveguides (one diffusion waveguide for each sub-pixel of the LCD panel) can be used without compromising light separation. It is difficult to make.

  Diffuse optical fibers or waveguides are known for backlighting applications (see, for example, U.S. Pat. No. 6,671,452 and No. 6079838), such diffusers are generally wide and bulky and are coupled to an additional diffuser layer located primarily behind the LCD panel, and the pixels or sub-pixels of the LCD panel. There is no direct coupling between the diffusers.

  Accordingly, there is a widely recognized need for an apparatus and method for optical resizing and / or backlight illumination that does not have the above limitations, and it is highly advantageous to have and provide it.

  The background art does not teach using embedded waveguides to achieve optical resizing, nor does it teach illumination light to one or more passive display panels. Embodiments of the present invention utilize embedded waveguide technology to achieve one-dimensional or two-dimensional optical resizing and / or backlighting.

  Accordingly, in one aspect of the present invention, an optical resizing device is provided. The apparatus includes a first optical resizing element having a plurality of waveguides designed and configured to achieve optical resizing in a first dimension, and to achieve optical resizing in a second dimension. And a second optical resizing element having a plurality of waveguides designed and constructed. The second optical resizing element is coupled to the first optical resizing element such that light exiting the first optical resizing element is incident on the second optical resizing element, and thus both the first and second optical resizing elements. Resizing is done in the dimension. At least one waveguide of the first and second optical resizing elements is at least partially tapered.

  According to further features in preferred embodiments of the invention described below, the plurality of waveguides of the first optical resizing element and the second optical resizing element are longitudinally arranged to achieve optical resizing. Formed and / or embedded in the substrate in an expanding array.

  According to still further features in the described preferred embodiments the longitudinally extending array includes waveguide layers, each layer extending from a first region of the layer to a second region of the layer, Thereby, the circumferential boundary is defined in the layer and the length characterizing the circumferential boundary is smaller in the first region than in the second region in order to achieve optical resizing.

  In another aspect of the invention, an optical resizing element is provided. The optical resizing element comprises a plurality of layers forming a substrate having a first facet and a second facet that is larger than the first facet. Each layer has an array of substantially parallel waveguides formed and / or embedded in the layer and extending from a first region of the layer to a second region of the layer. In this aspect, the layers are arranged in a partially overlapping optical arrangement whereby the second region of each layer is optically exposed at the second facet to achieve one-dimensional optical resizing.

  In yet another aspect of the invention, an optical resizing element is provided. The optical resizing element comprises a substrate formed from at least one layer, each layer being formed and / or embedded in the layer and extending from a first region of the layer to a second region of the layer, whereby the layer Having an array of waveguides defining a circumferential boundary therein. In order to achieve one-dimensional optical resizing, the length characterizing the circumferential boundary is smaller in the first region than in the second region.

  The optical device of this embodiment can also be used to provide illumination light to a passive display (including but not limited to a liquid crystal panel). Thus, according to yet another aspect of the present invention, a backlight assembly is provided. The backlight assembly is a component in a passive display device that includes a passive display panel having a plurality of pixel regions each defined by at least two sub-pixel locations that respectively correspond to at least two color channels that characterize the pixel region. Can act.

  The backlight assembly preferably includes a plurality of waveguides, which are formed and / or embedded in one or more substrates, such that each pixel region is illuminated by at least two waveguides. Each of the at least two waveguides is arranged to illuminate one subpixel position of the pixel region by a respective color channel.

  According to further features in preferred embodiments of the invention described below, the passive display device further includes a light diffuser positioned in front of the passive display panel.

  According to still further features in the described preferred embodiments the passive display device further comprises at least one additional passive display panel positioned in front of the passive display panel. The additional passive display panel is designed and configured to increase the extinction ratio of the passive display device.

  According to yet another aspect of the invention, a backlight assembly is provided, which includes a plurality of waveguides formed and / or embedded in one or more substrates, wherein at least one waveguide comprises (i) at least Demultiplexing light propagating into the waveguide in two color channels, and (ii) in each pixel region in such a way that different sub-pixel positions of the pixel region are illuminated by different color channels of at least two color channels Including an optical demultiplexer designed and configured to couple the light into. According to further features in preferred embodiments of the invention described below, the backlight assembly serves as a component in a passive display device.

  According to further features in preferred embodiments of the invention described below, the backlight assembly includes a plurality of light sources. According to still further features in the described preferred embodiments the at least one light source is a light emitting diode. According to still further features in the described preferred embodiments the at least one light source is a laser light source.

  According to still further features in the described preferred embodiments the light source is arranged such that at least one waveguide is provided by one light source.

  According to still further features in the described preferred embodiments the light source is arranged such that at least one waveguide is provided by at least two light sources.

  According to still further features in the described preferred embodiments at least a few of the plurality of light sources are configured to provide polarization. According to still further features in the described preferred embodiments the backlight assembly further includes a polarizer positioned between the plurality of light sources and the plurality of waveguides to polarize light exiting the light source.

  According to still further features in the described preferred embodiments the at least one light source comprises a monochromatic light source.

  According to still further features in the described preferred embodiments at least one of the plurality of waveguides is in the layer of the backlight assembly from at least one input region of the layer to at least one output region of the layer. Arranged in a row with respect to the passive display panel.

  According to still further features in the described preferred embodiments the waveguide is such that in each layer the waveguide extends from at least one input region of the layer to at least one output region of the layer, thereby defining a peripheral boundary within the layer. In addition, they are arranged in layers on the substrate. According to a preferred embodiment of the present invention, the length characterizing the perimeter boundary is smaller in at least one input region than in at least one output region.

  According to still further features in the described preferred embodiments the backlight assembly includes one or more input substrates and one or more output substrates, each layer in the input substrate being optically coupled to one layer of the output substrate. The

  According to further features in the described preferred embodiments, the separation distance between layers in the output substrate can be matched to the separation distance between sub-pixels along a column of the passive display panel. Furthermore, the separation distance between the waveguides of the output substrate in the output region is preferably compatible with the separation distance between the subpixels along the row of the passive display panel.

  According to still further features in the described preferred embodiments at least one layer of the output substrate is designed and configured to emit light received from each layer of the input substrate in a plurality of directions. According to still further features in the described preferred embodiments at least one layer of the input substrate is designed and configured to emit light in at least two different directions.

  According to still further features in the described preferred embodiments the waveguides are arranged in layers with an optical arrangement partially overlapping in the substrate. In this embodiment, each layer includes a waveguide that extends from at least one input region of the layer to at least one output region of the layer, thereby allowing the output region to emit light that propagates in the waveguide of the layer. It is preferable to be exposed optically.

  According to further features in preferred embodiments of the invention described below, the input region includes a plurality of sublayers, and at least a few waveguides have different sublayers of the at least one input region to form an input facet of the layer. Are stacked to extend from

  According to still further features in the described preferred embodiments the at least one waveguide is tapered.

  According to still further features in the described preferred embodiments the waveguides are such that, for each waveguide, the termination portion of the input region is substantially collinear with at least one optical path characterizing at least one light source. Located in the input area layer.

  According to still further features in the described preferred embodiments the backlight assembly comprises a plurality of redirecting elements formed in at least one waveguide and configured to redirect light out of the at least one waveguide Further included.

  One or more redirecting elements can be mirrors (eg, total internal reflection mirrors, etched mirrors, mirrors coated with highly reflective coatings, planar mirrors, non-planar mirrors), wedge structures (eg, diffractive wedge structures), Bragg It can be a reflector or a holographic optical element.

  According to still further features in the described preferred embodiments the redirecting element is arranged to illuminate a plurality of sub-pixel positions along each column of the passive display panel.

  According to still further features in the described preferred embodiments each redirecting element is arranged in at least one waveguide so as to illuminate one subpixel position along the column.

  According to still further features in the described preferred embodiments at least one turning element is arranged in at least one waveguide so as to illuminate at least two subpixel positions along the column.

  According to still further features in the described preferred embodiments the at least one redirecting element includes light propagating in at least one waveguide such that the beam redirecting of the light beam is higher along the column than perpendicular to the column. Designed and configured to redirect the beam.

  According to still further features in the described preferred embodiments the at least one redirecting element is designed and configured such that the light beam is confined along the column to at least two subpixel locations.

  According to still further features in the described preferred embodiments the redirecting elements are arranged in such a way that at least two rows of sub-pixel positions of the passive display panel are illuminated by waveguides in each layer.

  According to still further features in the described preferred embodiments at least a few waveguides include a core and a cladding, the core having a higher index of refraction than the cladding, such that the light is focused by the cladding following the turn. It is shaped.

  According to still further features in the described preferred embodiments at least a few redirecting elements are designed and configured such that at least one waveguide of at least one layer emits light from at least two spaced locations. The According to still further features in the described preferred embodiments the separation distance between the at least two spaced apart positions is equal to the line separation distance characterizing the passive display panel.

  According to still further features in the described preferred embodiments the at least one redirecting element redirects the first part of the light propagating into the waveguide out of the layer and the second part of the light is partially reflected A partially reflecting element positioned in the waveguide to propagate through the element to the waveguide.

  According to still further features in the described preferred embodiments the substrate of the backlight assembly includes at least one reflective layer. According to still further features in the described preferred embodiments the reflective layer is characterized by a reflectivity gradient along the waveguide.

  According to still further features in the described preferred embodiments each waveguide is designed and configured such that the illumination area of the waveguide is approximately equal to the area of the subpixel location illuminated thereby.

  According to still further features in the described preferred embodiments, each waveguide is designed and configured such that the illumination area of the waveguide is substantially smaller than the area of the subpixel location illuminated thereby.

  According to still further features in the described preferred embodiments the waveguides are arranged such that each subpixel location is illuminated by a plurality of waveguides.

  According to still further features in the described preferred embodiments each layer is designed and configured to allow emission of light propagating in the layer's waveguide to a subpixel location corresponding to a single color channel. The

  According to still further features in the described preferred embodiments each layer is designed and configured to allow the emission of light propagating in the waveguide to subpixel locations corresponding to at least two color channels.

  According to still further features in the described preferred embodiments at least a few layers of the partially overlapping optical arrangement include: (i) a waveguide extending from the first input region of the layer to the first output region of the layer, provided that One output region is optically exposed to allow emission of light to a sub-pixel location corresponding to the first color channel; and (ii) from the second input region of the layer to the second output region of the layer An extending waveguide, except that the second output region is optically exposed to allow emission of light to a subpixel location corresponding to the second color channel.

  According to still further features in the described preferred embodiments the at least one layer of the partially overlapping optical arrangement includes a single input region and a single output region. In particular, this type of layer waveguide extends from the layer input region to the layer output region, the output region being optically exposed to allow emission of light to a sub-pixel location corresponding to the third color channel. Is done.

  According to still further features in the described preferred embodiments the partially overlapping optical arrangement is characterized by an exposure length that can be adapted to the separation distance between the columns characterizing the passive display panel.

  According to still further features in the described preferred embodiments the exposure length is selected to establish optical communication between at least two columns of the passive display panel and the output area. According to further features in the described preferred embodiments, the separation distance between the waveguides along the output region can be adapted to the separation distance between the rows characterizing the passive display panel.

  According to still further features in the described preferred embodiments the backlight assembly or passive display device further comprises a reflective layer positioned to reflect ambient light to illuminate the passive display panel with ambient light.

  According to still further features in the described preferred embodiments the reflective layer is located between the plurality of waveguides and the passive display panel.

  According to still further features in the described preferred embodiments the plurality of waveguides are located between the reflective layer and the passive display panel.

  According to still further features in the described preferred embodiments the input region and the output region are provided on opposite sides of the layer.

  According to still further features in the described preferred embodiments the input region and the output region are parallel.

  According to still further features in the described preferred embodiments the input region and the output region are provided on adjacent sides of the layer.

  According to still further features in the described preferred embodiments the input region and the output region are substantially orthogonal.

  According to still further features in the described preferred embodiments the input region and the output region are provided on the same side of the layer.

  According to still further features in the described preferred embodiments the input region and the output region are substantially collinear.

  According to still further features in the described preferred embodiments the backlight assembly includes a first facet and a second facet that is larger in size than the first facet, whereby the waveguide of the assembly is from the first facet to the second facet. Extends to facet.

  According to further features in preferred embodiments of the invention described below, the first region and the second region are located on opposite sides of the layer.

  According to still further features in the described preferred embodiments the first region and the second region are located on adjacent sides of the layer.

  According to still further features in the described preferred embodiments the first region and the second region are located on the same side of the layer.

  According to still further features in the described preferred embodiments the first region and the second region are substantially parallel.

  According to still further features in the described preferred embodiments the first region and the second region are substantially orthogonal.

  According to still further features in the described preferred embodiments the first region and the second region are substantially collinear.

  According to still further features in the described preferred embodiments at least one of the optical resizing elements includes a graded layer for achieving optical resizing.

  According to still further features in the described preferred embodiments at least one of the optical resizing elements includes a terrace for achieving optical resizing.

  According to still further features in the described preferred embodiments any of the above optical devices, including (but not limited to) an optical resizing element and a backlight assembly (first or second), the light is first Designed and configured to enter the optical device while propagating in the direction and exit the optical device while propagating in the same direction.

  According to still further features in the described preferred embodiments any of the optical devices described above is such that light is incident on the optical device while propagating in the first direction and propagating in a second direction different from the first direction. Designed and configured to exit the optical device.

  According to still further features in the described preferred embodiments the second facet is substantially parallel to the first facet.

  According to still further features in the described preferred embodiments the second facet is substantially orthogonal to the first facet.

  According to still further features in the described preferred embodiments the second facet is inclined with respect to the first facet.

  According to still further features in the described preferred embodiments the second facet and the first facet are substantially coplanar.

  According to still further features in the described preferred embodiments one optical resizing element is configured and designed to receive light from a plurality of light sources and transmit the light to another optical resizing element .

  According to still further features in the described preferred embodiments the apparatus further comprises at least one additional optical resizing element that receives light from at least one additional light source and transmits the light to the second optical resizing element. Prepare.

  According to still further features in the described preferred embodiments the additional light source comprises a monochromatic light source.

  According to still further features in the described preferred embodiments any of the above optical devices comprising (first or second) optical resizing elements and backlight assemblies (but not limited to) Designed and configured to emit in the direction. The light can be emitted from different light sources, where each direction belongs to a different light source. The light can also be emitted from a single light source or another optical resizing element, another substrate of the backlight assembly, in which case the same light is emitted in multiple directions. For example, a single image can be formed on two different facets of the device, and the same backlight assembly can provide illumination light to multiple passive display panels.

  According to still further features in the described preferred embodiments the apparatus is further at least one positioned in one of at least two different directions and configured to receive light from the first optical resizing element. With two additional optical resizing elements.

  According to still further features in the described preferred embodiments at least one of the optical resizing elements comprises a plurality of partial optical resizing elements, each partial optical resizing element performing partial optical resizing in a respective dimension. Designed and configured to achieve.

  According to still further features in the described preferred embodiments the device or optical resizing element further comprises a diffusion layer attached or etched to the second facet.

  According to still further features in the described preferred embodiments the device or optical resizing element further comprises an expansion structure.

  According to still further features in the described preferred embodiments the extension structure includes a holographic optical element.

  According to still further features in the described preferred embodiments the expansion structure comprises a stack of layers in which high and low index regions are alternately patterned.

  According to still further features in the described preferred embodiments the expansion structure comprises a stack of layers patterned with grooves.

  According to still further features in the described preferred embodiments the extension structure comprises a stack of tapered waveguide layers.

  According to still further features in the described preferred embodiments the expansion structure includes a mirror. According to still further features in the described preferred embodiments the mirror comprises a total internal reflection mirror. According to still further features in the described preferred embodiments the mirror is coated with a highly reflective coating.

  According to still further features in the described preferred embodiments the expansion structure includes a Bragg reflector.

  According to still further features in the described preferred embodiments the at least one optical resizing element is designed and configured to polarize light.

  In an additional aspect of the invention, an optical resizing device is provided. The apparatus includes a plurality of layers forming a substrate having a first facet and a second facet, the plurality of layers being arranged in a partially overlapping optical arrangement. Each layer has an array of waveguides formed and / or embedded in the layer and extending from a first region of the layer to a second region of the layer, thereby defining a circumferential boundary within the layer. The length characterizing the circumferential boundary is smaller in the first region than in the second region, and the second region is optically exposed to the second facet.

  According to further features in preferred embodiments of the invention described below, the first facet is defined by the ends of overlapping regions of the plurality of layers.

  According to still further features in the described preferred embodiments each layer is partially exposed to the first facet.

  According to still further features in the described preferred embodiments at least a few layers include mirrors for redirecting light propagating in the plurality of waveguides out of the layers. According to still further features in the described preferred embodiments at least a portion of the mirror is a total internal reflection mirror. According to still further features in the described preferred embodiments at least a portion of the mirror is an etched mirror. According to still further features in the described preferred embodiments at least a portion of the mirror is coated with a highly reflective coating.

  According to still further features in the described preferred embodiments at least a portion of the mirror includes a planar facet.

  According to still further features in the described preferred embodiments at least a portion of the mirror includes non-planar facets.

  According to still further features in the described preferred embodiments at least a few layers include a Bragg reflector for redirecting light propagating in the plurality of waveguides out of the layer.

  According to still further features in the described preferred embodiments at least a few layers include holographic optical elements for diverting light propagating in the plurality of waveguides out of the layers.

  According to still further features in the described preferred embodiments the device is characterized by a field of view selected small enough to substantially maintain the brightness of the light resized by the device.

  In yet an additional aspect of the invention, a method of manufacturing an optical resizing element is provided. The method includes: (a) forming a plurality of extended arrayed waveguides on a substrate extending from a first region of the substrate to a second region of the substrate, thereby providing a layer of the waveguide; ) Repeating step (a) a plurality of times thereby providing a plurality of layers; (c) a first facet defined by ends of the plurality of layers; and an exposed surface of one of the plurality of layers. Laminating a plurality of layers to form a second facet to be defined, thereby manufacturing an optical resizing element.

  According to still further features in the described preferred embodiments the method further comprises (d) a plurality of substantially parallel waveguides extending from the first region of the substrate to the second region of the substrate on the substrate. Forming and thereby providing a layer of the waveguide; (e) repeating step (d) a plurality of times thereby providing a plurality of layers; (f) forming a first facet and a second facet; Laminating the plurality of layers in a partially overlapping optical array, wherein the second region of each layer is optically exposed, such that the second facet is defined by the optically exposed portions of the plurality of layers; And (g) light can be propagated from the optical resizing element to the second optical resizing element in the first dimension in the optical resizing element. Inside optical resizing element It is to resize the light in the second dimension, and a step of optically coupling the optical resizing element to the second optical resizing element.

  In yet an additional aspect of the invention, a method of manufacturing a plurality of optical resizing elements is provided. The method includes: (a) forming a plurality of waveguides on a substrate extending from a first region of the substrate to a second region of the substrate, thereby providing a layer of the waveguide; and (b) step (a ) A plurality of times thereby providing a plurality of layers, (c) stacking a plurality of layers to provide a stack, and (d) providing at least a stack of optical resizing elements. Performing a single cut.

  In a further aspect of the invention, a method of manufacturing an optical resizing element is provided. The method includes: (a) forming a plurality of parallel waveguides on the substrate extending from the first region of the substrate to the second region of the substrate, thereby providing a layer of the waveguide; and (b) Repeating (a) multiple times thereby providing multiple layers; (c) forming first and second facets, the second facet being defined by the optically exposed portions of the multiple layers And stacking a plurality of layers in a partially overlapping optical arrangement in which the second region of each layer is optically exposed, thereby producing an optical resizing element.

  According to still further features in the described preferred embodiments the method further comprises (d) repeating steps (b)-(c) to form a second optical resizing element; and (e) optical Light can be propagated from the resizing element to the second optical resizing element so that the light is resized in the first dimension in the optical resizing element and in the second dimension in the second optical resizing element. And optically coupling the optical resizing element to the second optical resizing element.

  In yet another aspect of the invention, a method of manufacturing an optical resizing device is provided. The method includes: (a) forming a plurality of waveguides on a substrate extending from a first region of the substrate to a second region of the substrate, whereby the first region is characterized by a length that is smaller than the second region. Defining a circumferential boundary to be formed in the substrate; (b) repeating step (a) a plurality of times thereby providing a plurality of layers; (c) forming a first facet and a second facet; Laminating a plurality of layers in a partially overlapping optical arrangement, wherein a second region of each layer is optically exposed, such that two facets are defined by optically exposed portions of the plurality of layers, thereby Manufacturing an optical resizing device.

  According to still further features in the described preferred embodiments the method further comprises positioning a mirror for redirecting light propagating in the plurality of waveguides out of the substrate.

  According to still further features in the described preferred embodiments the method further comprises the step of cutting the layer after forming the layer to form at least one of the first facet and the second facet. Including.

  According to still further features in the described preferred embodiments the method performs the cutting step such that at least one facet is inclined.

  According to still further features in the described preferred embodiments the method further includes a plurality of layers for forming a layer end exposing each of the plurality of waveguide ends for each layer prior to the step of laminating the layers. Cutting the layer.

  According to still further features in the described preferred embodiments the method further comprises placing a polarizer on at least a portion of the layer prior to laminating the layers.

  According to still further features in the described preferred embodiments the method further comprises coupling at least one facet to a coupler. According to still further features in the described preferred embodiments the coupler includes a microlens array.

  According to still further features in the described preferred embodiments the method further comprises etching at least one facet to form a microlens array on the facet.

  According to still further features in the described preferred embodiments at least a few of the waveguides are tapered or partially tapered.

  According to still further features in the described preferred embodiments the tapering is characterized by a smooth profile.

  According to still further features in the described preferred embodiments the tapering is characterized by a substantially stepped profile.

  According to still further features in the described preferred embodiments the plurality of layers are partially exposed at the second facet.

  According to still further features in the described preferred embodiments at least a few of the plurality of waveguides form a planar optical circuit.

  According to still further features in the described preferred embodiments at least a few of the plurality of waveguides form an optical fiber array.

  According to still further features in the described preferred embodiments at least a few of the plurality of waveguides are single mode waveguides.

  According to still further features in the described preferred embodiments the waveguide is a multimode waveguide.

  According to still further features in the described preferred embodiments the optical resizing device or element further comprises a light absorber introduced between the cores of the waveguide.

  According to still further features in the described preferred embodiments at least a few waveguides include a core and a cladding, the core having a higher refractive index than the cladding.

  According to still further features in the described preferred embodiments at least a few waveguides comprise a photonic bandgap material.

  According to still further features in the described preferred embodiments the optical resizing device or element further includes a microlens array for coupling light to the optical resizing device or optical resizing element.

  According to still further features in the described preferred embodiments the optical resizing device or element further comprises at least one optical fiber bundle for coupling light into the optical resizing device or element.

  According to still further features in the described preferred embodiments the optical resizing device or element is flexible.

  According to still further features in the described preferred embodiments the optical resizing device or element is foldable.

  According to still further features in the described preferred embodiments the optical resizing device or element serves as a component of a display system.

  According to still further features in the described preferred embodiments the optical resizing device or element serves as a component of an autostereoscopic display system.

  In yet another aspect of the invention, there is provided a method for resizing a light spot comprising transmitting light through an optical resizing device of any of the above aspects or features.

  According to still further features in the described preferred embodiments the method further comprises the step of distorting the light spot to provide a brightness gradient and thereby compensate for inhomogeneous light loss.

  According to still further features in the described preferred embodiments the light constitutes an image in the manner.

  According to still further features in the described preferred embodiments the method further comprises distorting the image to provide a brightness gradient and thereby compensate for inhomogeneous light loss.

  The present invention has succeeded in addressing the shortcomings of presently known configurations by providing an optical resizing element, optical resizing device, and method that enjoy properties that far exceed the prior art.

  Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is described herein by way of example only and with reference to the drawings. In particular, with reference to the drawings in detail, the details shown are for the purpose of illustrating the preferred embodiment of the invention by way of example only and are the most useful and easily understood aspects of the principles and concepts of the invention. It is emphasized that it is presented to provide what is believed to be the explanation given. In this regard, details of the structure of the present invention are not shown in more detail than is necessary for a basic understanding of the present invention, but those skilled in the art will understand how to implement several forms of the present invention by way of the description given with reference to the drawings. Will become clear.
1a-2b are schematics of the prior art for manufacturing a fiber-based guidance magnifier.
FIGS. 3a-c illustrate waveguide longitudinally expanding arrays (FIG. 3a), partially tapered waveguides (FIG. 3b), and partially tapered waveguides, according to various exemplary embodiments of the present invention. Fig. 3c is a schematic view of a longitudinally extending array (Fig. 3c).
FIG. 3d is a schematic diagram of the embodiment of FIG. 3c with two or more layers.
4a-i are schematic illustrations of optical resizing elements in various exemplary embodiments of the present invention.
FIG. 5 is a schematic diagram of an optical resizing apparatus having two optical resizing elements in various exemplary embodiments of the present invention.
FIG. 6a is a schematic diagram of small facets of a receiving optical resizing element in various exemplary embodiments of the present invention.
FIG. 6b is a three-dimensional view of the waveguide of the device of FIG. 6a in various exemplary embodiments of the invention.
FIG. 7a is a three-dimensional schematic diagram of an apparatus of an embodiment in which the entrance and exit facets of each optical resizing element are substantially orthogonal to each other.
FIG. 7b is a three-dimensional schematic diagram of the apparatus of FIG. 7a in a preferred embodiment employing two pairs of optical resizing elements.
FIG. 8 is a schematic view of an apparatus in a preferred embodiment in which the facets of one optical resizing element are substantially parallel and the facets of the other optical resizing element are substantially orthogonal.
FIG. 9 is a schematic diagram of an apparatus in a preferred embodiment in which the facets of the optical resizing element are substantially coplanar.
Figures 10a-b are schematic illustrations of a photomask layout for fabricating an array of waveguides in accordance with various exemplary embodiments of the present invention.
FIGS. 11a-b are schematic views of a process for fabricating a waveguide that is tapered in both the vertical and lateral directions.
12a-f are schematic diagrams of an optical resizing device in a preferred embodiment using multiple light sources.
Figures 13a-c are schematic illustrations of the apparatus in a preferred embodiment where there are two or more optical outputs from the apparatus.
Figures 14a-b are schematic illustrations of the apparatus in a preferred embodiment where the apparatus includes one or more additional optical elements.
FIG. 15 is a schematic diagram of layers of an optical resizing element in a preferred embodiment where the layers include polarizers.
Figures 16a-b are schematic views of the coupling between the device and the light source in a preferred embodiment where the light source is an image source.
FIG. 17 is a schematic diagram of a preferred embodiment in which an input image is focused on the device using a lens.
Figures 18a-b are schematic views of the coupling between the device and the light source in a preferred embodiment in which one or more fiber bundles are used.
FIG. 19 is a schematic diagram of one layer of an optical resizing element in a preferred embodiment in which the waveguide is tilted with respect to the edge of the layer.
20-22f are schematic views of an optical resizing device in a preferred embodiment in which the device is manufactured according to the principle of partially overlapping optical arrangements.
FIGS. 23a-b are a schematic side view (FIG. 23a) and a schematic top view (FIG. 23b) of a portion of a facet of a device similar to that of FIGS. 20-22 in a preferred embodiment where the facet has a two-dimensional stepped shape. ).
23c-d are schematic illustrations of mirror shapes according to various exemplary embodiments of the present invention.
Figures 24a-e are schematic side views of an optical resizing element with a two-dimensional stepped or tilted profile according to various exemplary embodiments of the present invention.
FIG. 25 is a schematic view of a bendable optical resizing device according to a preferred embodiment of the present invention.
Figures 26a-b are schematic illustrations of configurations in which light is coupled out of the device via an array of transmissive elements, according to various exemplary embodiments of the present invention.
FIGS. 27a-b are schematic views of a process for manufacturing a tilted optical resizing element in various exemplary embodiments of the invention.
Figures 27c-h are schematic illustrations of expansion structures according to various exemplary embodiments of the present invention.
28a-c are a schematic top view (FIG. 28a-b) and schematic side view (FIG. 28c) of a layer of a device similar to the device of FIGS. 20-22 in a preferred embodiment where the layer is a lightweight layer. .
Figures 29a-e are schematic illustrations of a suitable folding technique for manufacturing an apparatus similar to that of Figures 20-22, according to various exemplary embodiments of the present invention.
Figures 30a-b are schematic illustrations of simultaneous processes for manufacturing multiple optical resizing elements in various exemplary embodiments of the invention.
FIG. 31 is a schematic diagram of an apparatus similar to that of FIGS. 20-22 in a preferred embodiment where the apparatus receives light from a plurality of light sources.
32a-b are a schematic top view (FIG. 32a) and a schematic cross-sectional view (FIG. 32) of a device similar to that of FIGS. 20-22 in a preferred embodiment where the device receives optical input in the form of a plurality of monochromatic light sources. 32b).
FIGS. 33a-c are schematic diagrams of techniques for coupling light out of a device layer similar to that of FIGS. 20-22, according to various exemplary embodiments of the present invention.
Figures 34a-35c are schematic views of an apparatus similar to that of Figures 20-22 in a preferred embodiment where the apparatus is used to provide autostereoscopic images.
FIG. 36 is a schematic diagram of different optical regions in the field of view of a device similar to that of FIGS. 34a-35c.
FIGS. 37a-b are a schematic diagram of one layer (FIG. 37a) and the resulting field of view (FIG. 37b) in a preferred embodiment in which multiple autostereoscopic images are provided.
FIG. 38 is a schematic diagram of an optical resizing device in a preferred embodiment where the input image has non-uniform brightness to compensate for differential waveguide losses.
FIG. 39a is a schematic diagram of layers of an optical resizing element in a preferred embodiment where the layers include a light absorber.
FIG. 39b is a schematic diagram of a waveguide with variable cross section according to a preferred embodiment of the present invention.
FIG. 40 is a schematic diagram of a procedure for improving the brightness of output light in various exemplary embodiments of the invention.
FIG. 41 is a schematic diagram of a procedure for modifying the field of view of an apparatus in various exemplary embodiments of the invention.
FIG. 42a is a schematic diagram of a conventional edge-lit LCD device.
42b-c are schematics of backlight technology designed to overcome the inherent 2/3 output loss.
43a-c are schematic illustrations of a display device using one or more optical elements of this embodiment.
Figures 44a-c are schematic views of a passive display panel (Figures 44a and 44c) and its pixel area (Figure 44b).
FIG. 45 is a schematic illustration of a backlight assembly according to various exemplary embodiments of the present invention.
46a-b are schematic views of the color distribution of backlight illumination provided by a backlight assembly to a passive display panel, according to various exemplary embodiments of the present invention.
47a-b couples light to a backlight assembly, where the waveguides are arranged in each layer such that the termination portion of each waveguide is substantially collinear with at least one optical path characterizing the light source. 1 is a schematic diagram of a preferred technique for
48a-e are schematic diagrams of techniques for redirecting light out of a waveguide, according to various exemplary embodiments of the present invention.
Figures 49a-b are schematic illustrations of suitable layer designs for configurations in which layer waveguides illuminate one (Figure 49a) and two (Figure 49b) subpixels per row.
FIG. 50 schematically shows a side view of a stack of layers of the type shown in FIG. 49b.
FIG. 51 is a schematic diagram of a single layer that includes a first waveguide that branches into a plurality of second waveguides that extend into an input region, in accordance with various exemplary embodiments of the present invention.
52a-b are schematic views of a preferred embodiment for guiding multiple color channels in a single layer, with multiple first waveguides extending from one input region to multiple output regions.
53a-b include waveguides in which the layers extend from multiple input regions to multiple output regions, with each color channel entering the layer at one input region, propagating through the waveguide, and at one output region. FIG. 2 is a schematic diagram of a preferred embodiment for guiding multiple color channels out of a layer into a single layer.
FIG. 54a is a schematic diagram of a single layer according to another preferred embodiment for guiding multiple color channels in a single layer. In this embodiment, the layer includes two input areas and four output areas.
FIG. 54b is a schematic diagram of a side view of an optical device having an alternating arrangement of the layers of FIG. 49a and the layers of FIG. 54a, according to various exemplary embodiments of the present invention.
55a-c are schematic views of the layers of the waveguide in a preferred embodiment where the waveguide extends from the input region to a plurality of output regions.
56a-b are schematic illustrations of a preferred embodiment in which a small number of layers include two input regions and multiple output regions.
FIG. 57a is a schematic diagram of a preferred embodiment LCD device including an in-front light diffuser.
FIG. 57b is a schematic diagram of a preferred embodiment LCD device including two passive displays.
FIG. 58 is a schematic diagram of a preferred embodiment LCD device in which monochromatic light propagates into the waveguide of the backlight assembly.
FIG. 59 is a schematic diagram of a preferred embodiment LCD device operating in transmissive mode.
FIG. 60 is a schematic diagram of a preferred embodiment LCD device operating in continuous color mode.
61a-c and 62a-c are schematics of additional optical coupling techniques (not particularly limited) useful for embodiments with multiple output regions (see, eg, FIGS. 55a-56b).
FIG. 63 is a schematic diagram of a backlight assembly that receives optical input from 12 monochromatic light sources.
64a-b are schematic views of a preferred embodiment backlight assembly including a microlens array.

  Embodiments of the present invention include methods, optical elements, and apparatus that can be used for optical resizing or illumination light. In particular, the present invention can be used to provide optical resizing and / or illumination light in various applications such as display systems and the like, but is not limited thereto.

  As used herein, the term “optical resizing” refers to the expansion or contraction of a light wavefront, which can be, for example, a planar light spot. In other words, optical resizing refers to the change (expansion or contraction) of the area occupied by the light wavefront. For example, when light constitutes an image there, optical resizing refers to the enlargement or reduction of the image, which can be achieved by a separation or size change of the image elements (eg, pixels) of the image. . The size of the area occupied by the light wavefront is here interchangeably referred to as the cross-sectional area of the light beam.

  The term “illumination light” refers to monochromatic light or chromatic light. Typically, although not required, the illumination light does not constitute an image and is used to illuminate a predetermined area. For example, the illumination light can be used as a backlight for a passive display panel.

  As used herein, the term “passive display panel” refers to a pixelated panel where the pixels do not produce light and require a backlight for operation. Representative examples of passive display panels include, but are not limited to, liquid crystal panels and electrophoretic panels. In various embodiments of the present invention, the passive display panel is a liquid crystal panel.

  The illumination light can also undergo optical resizing as described above. For example, the illumination light can come from one or more light sources of relatively small dimensions and can be expanded to illuminate a large area.

  The principles and operation of an apparatus and method according to the present invention may be better understood with reference to the drawings and accompanying descriptions.

  Before describing at least one embodiment of the present invention in detail, the present invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated by the drawings. Must understand. The invention is capable of other embodiments or of being practiced or carried out in various ways. Also, it should be understood that the terminology and terminology used herein is for the purpose of description and should not be considered limiting.

  Embodiments of the present invention utilize embedded waveguide technology to achieve optical resizing or illumination light. The buried waveguide can be of any type known in the art, such as a planar optical circuit (PLC) waveguide or other array. Further, the waveguide can be a single mode or a multimode waveguide. The cross section of the waveguide can be substantially circular, substantially rectangular, or other geometric shape.

  It is preferred, but not essential, that the buried waveguides be arranged in one or more layers so that they can be manufactured in layers. However, depending on the application, optical resizing need not necessarily be so, as it can be achieved by an optical resizing element made from a bulk material as described in more detail below.

  In embodiments in which the embedded waveguides are arranged in layers, light may enter or exit the layers through their surfaces or through their ends, as described in further detail below. it can. Optical resizing and / or backlighting of embodiments of the present invention can be achieved by a longitudinally extending arrangement of any type and any shape of waveguide. In particular, the longitudinally extending array can include a tapered waveguide, a partially tapered waveguide, an untapered waveguide, or any combination thereof.

  In general, a longitudinally extending waveguide refers to an array of waveguides that increases along another direction when the distance between the different waveguides is measured in one direction.

  Referring now to the drawings, FIGS. 3a-c illustrate longitudinally expanding arrays of non-tapered waveguides (FIG. 3a), partially tapered waveguides (FIG. 3), according to various exemplary embodiments of the present invention. 3b) and a longitudinally extending array of partially tapered waveguides (FIG. 3c). As shown, the distance between the different waveguides increases along the longitudinal direction 19 when measured along the transverse direction 17. FIG. 3d illustrates the embodiment of FIG. 3c with multiple layers.

  Before presenting a more detailed description of embodiments of the present invention, attention is given to the advantages and potential applications provided by them. The use of a buried waveguide allows planar path selection and the production of tapered elements. Further, when using PLC technology, each or some of the waveguides can include several portions that are interconnected via mirror corners. Such a design can be used to reduce or eliminate waveguide bending and thus reduce the thickness of the final product.

  Another advantage of embodiments of the present invention is that PLC technology allows the manufacture of waveguides with a rectangular core cross section, thereby increasing the fill factor and reducing coupling losses.

  A special feature of embodiments of the present invention is that when a waveguide is used in a backlight assembly for a passive display panel, a passive display device such as an LCD device can be manufactured without the use of a color filter. is there. It is recognized that color filters are expensive and they cause more than 2/3 of the output loss because they transfer only one color. Therefore, embodiments of the present invention are advantageous over conventional LCD devices in terms of cost and optical transparency.

  The use of embedded waveguides allows the production of flexible elements that can be easily assembled. For example, an optical device can be assembled with partially overlapping flexible layers so that the entire layer can be bent instead of or in addition to bending individual waveguides. In addition, the layered production process facilitates the production of foldable optical devices, whereby different layers are only partially deposited between them.

  4a-b, in one aspect of the invention, an optical element, generally referred to herein as element 10, is provided. The optical element 10 can serve as an optical resizing element or as an element for providing illumination light to, for example, a passive display panel, as will be described in further detail below. Device 10 includes a substrate 12 formed from one or more layers 14. Each layer of element 10 has an array of waveguides formed and / or embedded therein. The separation distance between adjacent layers is denoted by t. In a preferred embodiment of the present invention, the array of waveguides in each layer is an array that extends in the longitudinal direction. FIG. 4 b is a schematic diagram of the layer 14 of the device 10. Layer 14 preferably includes a plurality of waveguides 16 that extend from a first region 18 to a second region 20 of layer 14, thereby defining a circumferential boundary 22 within layer 14. The boundary 22 is illustrated as a dashed line in FIG. 4b. The first region 18 can be an input region where light enters the waveguide, and the second region 20 can be an output region where light exits the waveguide. In the illustrated configuration shown in FIG. 4 b, the first region 18 and the second region 20 are substantially parallel and located on the opposite side of the layer 14. However, it may not be necessary to make the regions parallel to each other, depending on the application. Thus, regions 18 and 20 can have any geometric relationship between them. For example, as further illustrated below (see, eg, FIGS. 4e-f), regions 18 and 20 can be on adjacent sides of layer 14 (eg, in a substantially orthogonal relationship) or on the same side of layer 14 (eg, substantially In a collinear or substantially parallel displacement relationship).

  As used herein, “substantially parallel” refers to a relative orientation of less than 20 °, more preferably less than 10 °, most preferably less than 5 °, for example about 0 °. As used herein, the term “parallel” should be understood to be substantially parallel.

  As used herein, “substantially orthogonal” means from about 70 ° to about 110 °, more preferably from about 80 ° to about 100 °, most preferably from about 85 ° to about 95 °, such as about 90 °. Refers to relative orientation.

  As used herein, “substantially collinear” refers to a relative orientation of less than 20 °, more preferably less than 10 °, most preferably less than 5 °, for example about 0 °. Further, as used herein, “substantially parallel excursion” means that the facets are substantially parallel, but less than 50 mm, more preferably less than 1 mm, most preferably less than 0.1 mm, for example about 0. It also refers to a case where the displacement is substantially 01 mm.

  Further, although the waveguide is shown as having a substantially linear shape, it may not be necessary to do so because in some applications it may be desirable to have a non-linear (ie, curved) shape. In addition, the waveguide can be formed from non-contiguous sections that are interconnected by corner mirrors, as described in further detail below.

In either case, the length characterizing the boundary 22 is shorter in the first region 18 than in the second region 20. Accordingly, the distance S _x between adjacent waveguides along the region 18 is smaller than the distance Δx between adjacent waveguides along the region 20.

  One of ordinary skill in the art will appreciate that such an arrangement achieves a one-dimensional optical resizing defined by layer regions 18 and 20. For example, when region 18 acts as an input region and region 20 acts as an output region, the light beam enters the layer 14 from the first region 18, propagates through the waveguide 16, and exits from the second region 20. In this configuration, the light cross-sectional area is expanded in a direction substantially parallel to regions 18 and 20. Conversely, when the region 20 acts as an input region and the region 18 acts as an output region, the light beam enters the layer 14 from the second region 20 and exits from the first region 18. In this configuration, the light cross-sectional area is reduced in a direction parallel to regions 18 and 20.

  4c-d are schematic representations of the facets of element 10 in the preferred embodiment in which the layers are stacked such that smaller areas of the layer form smaller facets 24 and larger areas of the layer form larger facets 26. FIG. FIG.

  The waveguide can be tapered, as described, such that resizing is achieved by both the longitudinally extending array and the tapering of the individual waveguides. FIG. 4 e is a schematic diagram of a preferred embodiment using a tapered waveguide in a configuration where the first region 18 is substantially orthogonal to the second region 20. Still, the length characterizing the boundary 22 is preferably less in the first region 18 than in the second region 20 to ensure optical resizing. FIG. 4 f is a schematic diagram of a preferred embodiment using a tapered waveguide in a configuration where the first region 18 is collinear with the second region 20.

  Depending on the structure of the regions 18 and 20 of the layers of the element 10, the small facets 24 and the large facets 26 can have any geometric relationship between them. 4g-i schematically illustrate some geometric relationships between facets 24 and 26, according to various exemplary embodiments of the present invention. Thus, if the layer regions 18 and 20 are parallel and located on the opposite side of the layer (see, eg, FIG. 4b), the small facet 24 is parallel and opposite the large facet 26 (FIG. 4g). When regions 18 and 20 are aligned at an angle to each other (eg, substantially orthogonal, see eg, FIG. 4e), facets 24 and 26 are also aligned at the same angle (FIG. 4h). When regions 18 and 20 are located on the same side of the layer (eg, are substantially collinear, see eg, FIG. 4f), facets 24 and 26 are coplanar (FIG. 4i). It should be understood that the more detailed reference to the geometric relationships shown in FIGS. 4g-i is not intended to limit the scope of embodiments of the present invention to a particular angle between facets 24 and 26. . Thus, embodiments of the present invention assume any value for the angle between facets 24 and 26.

  Waveguides suitable for embodiments of the invention can have a high index core and a low index cladding, or can include a photonic bandgap material. Thus, a waveguide layer suitable for embodiments of the present invention is to etch a groove into a layer of low refractive index material that acts as, for example, a waveguide cladding, and a high refractive index material that acts as a waveguide core into the groove. It can be manufactured by depositing. The waveguide core can then be covered by a low refractive index additional layer that acts as an upper cladding layer.

  A waveguide of photonic bandgap material is manufactured by forming (eg, etching) an optical periodic structure on a substrate of dielectric material, leaving a stripe that does not have a periodic structure and acts as a core waveguide Can do. An optical periodic structure is characterized by a spatial periodic variation in the refractive index of a cycle in the sub-micrometer to micrometer range that defines a wavelength band (photonic band gap) in which no light propagation occurs. The optical periodic structure can then be covered by a cladding layer. An advantage of using a photonic band gap material is that there is no radiation loss in the photonic band gap, even in highly curved waveguide sections.

  Although not required, it is preferable to use PLC polymer lithography techniques (see, eg, Eldada et al., “Advanceds integrated polymers”, IEEE J. Selected Topics in QE, vol. 6, 54-68, 2000). ). Photobleaching processes [Gallo et al., “High-density interconnects for 2-dimensional VCSEL array sustained for mass scale production”, ITCom 321, 2001, 451-2001, 45, 2001, as an expected process for fabricating waveguide layers. ], Casting / molding process [Kopetz et al., "Polysiloxane optic waveguide integrated in printed circuit board", Elec. Lett. Vol. 40, 668-669, 2004], and soft lithography processes [Huang et al., “Bottom-up soft fabrication of three-dimensional multi-layer integrated optical microchips,” Phys. Lett. vol. 85, 3005 to 3007, 2004], but is not limited thereto.

  The waveguide of embodiments of the present invention may also be an array of optical fibers embedded in a layer using an adhesive material, preferably without an outer frame, as known in the art (for this purpose, for example, See U.S. Pat. Nos. 5,381,506, 6,597,845 and 6,885,800).

  The optical element according to the embodiment of the present invention preferably includes many waveguide layers. Typically, the number of layers is from several hundred layers (for example, about 500 layers) to several thousand layers (for example, about 5000 layers). When the optical element acts to provide backlight illumination to the passive display panel, the number of layers has an order of the square root of the number of pixels or subpixels on the passive display panel. For example, the number of layers can be the number of pixels or subpixels in a row of a passive display panel, or the number of pixels or subpixels in a column of the passive display panel, as described in further detail below.

  As used herein, when a quantity X is referred to as being on the order of another quantity Y, the quantity X can have any value from 0.1Y to 10Y.

  The layers can be stacked by processing the polymer wafer layers one after another or by stacking the stacked layers. Layers can also be stacked using a combination of these techniques. Once the wafer layers are stacked, the wafer is scored and the necessary facets are polished. Alternatively, the streaks can be sawed before stacking. It will be appreciated that because such optical elements are wide and short, many such elements can be assembled in a parallel process.

  The optical elements of embodiments of the present invention can be used for illumination and / or to achieve optical resizing as described. Thus, the optical element can be incorporated into many applications, including but not limited to display devices. In a display device, the optical element is the display unit of the device (in this case the optical element displays image information on one or more of its facets) or the backlight unit of the device (in this case the optical element transmits illumination light to the display unit). It can act as any component of

  43a-c are schematic views of the use of the optical element of the embodiment of the present invention. In FIG. 43a, the optical element is or acts as a component of the display unit 63 of the display device 60, and in FIGS. 43b-c, the optical element is a component of the backlight assembly 62 of the display device 60. Or act like that. As will be appreciated by those skilled in the art, in the exemplary configuration of FIG. 43a, the optical element transmits light 68 encoded by the image data, whereas in the configuration of FIGS. 43b-c, the optical element is preferably not encoded. The illumination light 66 is transmitted. The display device of FIGS. 43b-c is preferably a passive display device (eg, an LCD device), which further includes a passive display panel 64 and optionally a front polarizer 540. As shown in FIGS. 43 b-c, the panel 64 is supplied by illumination light 66 provided by a backlight assembly 62. When the electric field modulated by the image data is supplied to the liquid crystal module of the panel 64, the optical characteristics of the liquid crystal are changed, and the illumination light passing through the panel 64 is encoded by the image data.

  A schematic diagram of the passive display panel 64 is shown in FIG. 44a. Panel 64 has a plurality of pixel regions 52, each defined by two or more subpixel locations 54. The sub-pixel position of each pixel region corresponds to a color channel that characterizes the pixel region. Thus, the two color channel pixel regions have two pixel locations and the three color channel pixel regions have three pixel locations.

  A single pixel region of three color channels (eg, red channel, green channel and blue channel) is shown schematically in FIG. 44b. The three subpixel positions are indicated by 54a, 54b and 54c. When an optical element of an embodiment of the present invention is used to illuminate panel 64, it may illuminate each subpixel location with light characterized by a subspectrum corresponding to the respective color channel of the subpixel location. preferable.

  In one embodiment shown in FIG. 43b, monochromatic light propagates into the waveguide and illuminates the subpixel location. In particular, the pixel region 52 is illuminated by at least two waveguides, each arranged to illuminate one of the sub-pixel locations of the pixel region 52 by a respective color channel. Thus, in this embodiment, the waveguides guiding the different color channels specify different subpixel positions of the panel 64. However, one or more waveguides can be aligned such that one waveguide illuminates several subpixel locations associated with a particular color channel. Alternatively, each subpixel location can be illuminated by a different waveguide.

  In another embodiment shown in FIG. 43c, polychromatic light (eg, white light) propagates into the waveguide and is demultiplexed to different subpixel locations near the pixel area. Illumination of each sub-pixel location by the respective color channel allows the use of a passive display panel without a color filter known to transmit 1/3 of the light produced by each pixel. This is advantageous because it increases light efficiency and significantly reduces the cost of the display device.

In general, the pixel areas and sub-pixel positions of the panel 64 are arranged in a grid. In the representative example shown in FIG. 44a, the grid is rectangular and has sub-pixel resolution along the rows of the rectangular grid and pixel resolution along the columns of the rectangular grid. Thus, the column width is approximately equal to the width of the sub-pixel position, and the row height is approximately equal to the pixel region height. The distance between adjacent sub-pixel positions in the same row are herein is the column distance between panel 64, indicated by W _c. The distance between adjacent sub-pixel positions in the column are herein a line spacing of the panel 64, indicated by H _r. It should be understood that the rectangular grid of FIG. 44a is presented for illustrative purposes only and is not intended to limit the scope of the invention to any particular geometric shape. For example, in another preferred embodiment, a triangular grid is used.

  Typically, although not required, the subpixel positions of each pixel region are in a predetermined fixed order (eg, the leftmost position for the red channel, the center position for the green channel, and the blue channel). In the rightmost position). In such an arrangement, two adjacent subpixel positions in the same row correspond to different color channels, while two adjacent subpixel positions in the same column correspond to the same color channel. It should be understood that the terms “row” and “column” are introduced for clarity of explanation and should not be construed as a reference to any particular direction in space.

  In general, a “row” or “column” of pixels or subpixels refers to any one-dimensional array of pixels or subpixels. Thus, a pair of adjacent pixels or subpixels along such a one-dimensional array can share sides, vertices, or have any tangent relationship. The distinction between “row” and “column” is due to the color channel associated with two adjacent sub-pixels. Thus, a “column” of subpixel positions refers to a one-dimensional array of subpixel positions where all subpixel positions are associated with the same color channel, and a “row” of subpixel positions is two along the one-dimensional array. Refers to a one-dimensional array of sub-pixel locations associated with color channels where every other adjacent sub-pixel location is different.

  In the representative example of FIG. 44a, columns are shown along line 552 and rows are shown along line 554. As shown, every second adjacent subpixel location along line 552 or 554 shares an edge. Another example of a column and row of subpixel locations is shown in FIG. 44 c where again the column is shown along line 552 and the row is shown along line 554. In this example, every second adjacent subpixel location along line 552 or 554 shares a vertex. FIG. 44c further shows the color association at each sub-pixel location. As shown, all subpixel locations along line 552 are associated with the same color channel (green in this example), and adjacent subpixel locations along line 554 are associated with different color channels.

  In any of the applications illustrated above, one or more optical elements can be used. For example, several optical elements that are similar in principle and operation (size is not essential) to element 10 can be assembled together to achieve an optical device used in any of the applications illustrated above. In various exemplary embodiments of the present invention, the optical elements can be used alone or in combination with other elements to achieve optical resizing in two dimensions, preferably two orthogonal dimensions. .

  The following is a description of a preferred embodiment in which several optical resizing elements are assembled for two dimensional optical resizing or to illuminate a passive display panel. A description of other preferred embodiments in which two-dimensional optical resizing or backlight illumination is achieved without such assembly is given below.

  Reference is now made to FIG. 5, which is a schematic illustration of an optical device 30 according to various exemplary embodiments of the present invention. The apparatus 30 preferably comprises a first optical resizing element 32 that achieves an optical resizing of a first dimension 36 and a second optical resizing element 34 that achieves an optical resizing of a second dimension 38. Elements 32 and 34 can each operate independently of element 10 described above. Alternatively, one of elements 32 and 34 can be manufactured similarly to element 10 and the other can be manufactured by conventional techniques.

  To achieve optical resizing in both the first dimension 36 and the second dimension 38, the element 34 is coupled to the element 32 such that light exiting the element 32 is incident on the element 34. Thus, element 34 acts as a light receiving element, while element 32 acts as a transmissive element within device 30. The coupling between elements 32 and 34 can be done in any manner known in the art, such as through direct contact, fiber bundles, or any other optical coupling arrangement. The optical resizing element is advantageously manufactured so that the small facets of one element coincide with the large facets of the other element. When manufactured in such a manner, one of the optical resizing elements is larger than the other. In particular, when the device 30 is used to expand a light beam (ie, the light beam has a cross-sectional area that is larger at the output than at the input), the first element is smaller than the second element and the device 30 contracts the light. The first element is larger than the second element.

  For example, in the embodiment shown in FIG. 5, elements 32 and 34 have light incident on a small facet 40 of element 32 and expanded along dimension 36 and exit element 32 through facet 42, preferably of element 32. Manufactured to enter element 34 through facet 44 having the size of facet 42. The light then propagates through the element 34 and is expanded along the dimension 38 and exits from the large facet 46 in an expanded state in both dimensions.

  If elements 32 and 34 are both manufactured in the same manner as element 10, they use the same photomask layout (eg, the photomasks shown in FIGS. 3a, 3c, 4e, and 4f), but use different layer thicknesses. Can be processed. Thus, for example, element 32 can be formed from a thinner layer that defines the large facets shown above in FIG. 4d (see also the three-dimensional view of FIG. 3d), while element 34 is It can be formed from a thicker layer that defines the small facets shown in 6a. A three-dimensional view of the waveguide of element 34 according to a preferred embodiment of the present invention is shown in FIG. 6b.

  Device 30 acts either as a display unit of the display device or as a backlight assembly. In the former case, element 32 preferably receives multicolor light (eg, white light) or monochromatic light encoded by the image data, while in the latter case, element 32 preferably receives uncoded light. When device 30 is used as a backlight assembly for a passive display panel, each subpixel location is preferably illuminated by light corresponding to the respective color channel of the subpixel location. When multicolor light enters element 32, the light is preferably demultiplexed near the pixel area, as will be described in further detail below.

  Reference is now made to FIG. 7a, which is a three-dimensional schematic view of apparatus 30 in an embodiment in which the inlet and outlet facets of each optical resizing element are substantially orthogonal to each other. In particular, at element 32, the small facet 40 is substantially orthogonal to the large facet 42, and at element 34, the small facet 44 is substantially orthogonal to the large facet 46. Facet 42 and facet 44 are preferably parallel and contact to allow optical coupling between element 32 and element 34. It should be understood that when transmitting an image using this embodiment (i.e., where the encoded light is incident on element 32), the image emanating from device 30 is a mirror image of the original image. The advantage of the embodiment shown in FIG. 7a is that there is less waveguide bending 48 and no scattered light from the beam propagating towards the large facets.

  The resizing technique of this embodiment can be repeated. In particular, the apparatus 30 can comprise two or more pairs of optical resizing elements, each pair functioning according to the above description. That is, one element of the pair achieves one-dimensional optical resizing, and the other element of the pair achieves other dimensions of optical resizing. This embodiment is particularly useful when high magnification or reduction is required, or to avoid handling high aspect ratio waveguides during the manufacturing process. For example, a magnification of 30 times can be achieved with two pairs of optical resizing elements, where the first pair provides a magnification of 3 times (two dimensions) and the second pair provides a magnification of 10 times (two dimensions). .

  A representative example of a preferred embodiment of the present invention is shown in FIG. 7b for the case where two pairs of optical resizing elements 32, 33, 34 and 35 are used. As shown in FIG. 7b, element 33 expands light beam 72 in one dimension (eg, along the x direction) to provide an expanded light beam 74, and element 35 extends light beam 74 in another dimension (eg, y). (In the direction) to provide an expanded light beam 76. In addition, element 32 expands light beam 76 in one dimension (eg, along the x direction) to provide extended light beam 78, and element 34 extends light beam 78 in another dimension (eg, along the y direction). ) Expand to provide an expanded light beam 80. Thus, the original light beam 72 is expanded twice along the x direction and twice along the y direction.

  The waveguide of each layer of the optical resizing element of the embodiment of the present invention can be formed using a photomask similar to the photomask shown above in FIG. 4e. The waveguide bend 48 shown in FIGS. 7a-b can be replaced with a corner mirror 50 (see FIG. 4e) to further reduce the thickness of the optical resizing element.

  Reference is now made to FIG. 8, which is a schematic illustration of the apparatus 30 of the preferred embodiment, wherein the facets of one optical resizing element are parallel and the facets of the other optical resizing element are substantially orthogonal. is there. With particular reference to the exemplary embodiment, in element 32 (a transmissive element in this example), the small facet 40 is parallel to the large facet 42 and in element 34 (a light receiving element in this example), the small facet 44 becomes a large facet 46 Substantially orthogonal. Facet 42 and facet 44 are parallel and preferably contact so that optical coupling between element 32 and element 34 is possible. The advantage of this embodiment is that the waveguide length of element 32 is short (about half compared to the embodiment shown in FIG. 7), thus reducing the overall optical loss of the device. Nevertheless, since the input / output facets of the large element (element 34) are substantially orthogonal, the device enjoys the above advantages of reduced thickness and scattered light.

  Reference is now made to FIG. 9, which is a schematic illustration of a preferred embodiment apparatus 30 in which the facets of optical resizing elements (facets 40, 42, 44, and 46) are coplanar. The waveguides of each layer of the optical resizing element can be formed using a photomask similar to the photomask shown above in FIG. 4f where the regions 18 and 20 are collinear. Thus, the light beam 92 enters the small facet 40 of the element 32, propagates through the element 32, experiences a 180 ° turn, and exits from the facet 42 in an expanded state along the first dimension 36. The light beam exiting (expanded) from facet 42 is indicated by numeral 94 in FIG. The expanded light beam 94 is incident on a small facet 44 of element 34, propagates through element 34, undergoes additional expansion along dimension 38 and an additional turn of 180 °, along both dimensions 36 and 38. In the expanded state, the light is emitted from the facet 46. The light beam emanating from facet 46 is indicated by numeral 96. Thus, light passing through the device 30 experiences two expansions and two propagation direction changes, once in each dimension. To this effect, light propagates along its original direction, is expanded in two dimensions, and exits from the device 30.

  It should be understood that a more detailed reference to the above description for a particular propagation direction of an outgoing light beam is not intended to limit the scope of the invention to any incident-exit angular relationship. In various exemplary embodiments of the present invention, light exits device 30 at any predetermined angle relative to its angle of incidence. Thus, the angle between the incident and outgoing propagation directions of light can be 0 °, 90 °, 180 °, or any other angle. The incident-exit angle relationship depends on the orientation of the waveguide relative to the facet of the optical resizing element. For example, as will be described in more detail below, light can be incident on any of the optical resizing elements of device 30 at a right angle to the surface of the input facet and emitted non-perpendicularly from the output facet. As will be appreciated by those of ordinary skill in the art, in the case of parallel or substantially orthogonal facets, such a configuration corresponds to an incident-exit angle other than 0 °, 90 °, or 180 °.

  In general, since device 30 typically includes small and large elements, most or all of the area of device 30 has a large element thickness. As will be appreciated by those skilled in the art, the thickness of each optical resizing element can be rather small due to the extended arrangement of waveguides. This thickness can be further reduced by down-tapering the waveguide in a predetermined section of each layer. Representative examples of the thickness of the optical resizing element of embodiments of the present invention include, but are not limited to, a thickness of about 0.1 mm to about 100 mm, more preferably about 1 mm to about 10 mm.

  Reference is now made to FIGS. 10 a-b, which are schematic illustrations of a photomask layout for fabricating an array of waveguides according to various exemplary embodiments of the present invention. Figures 10a-b show a preferred embodiment in which regions 18 and 20 are parallel and located on the opposite side of the layer. Those of ordinary skill in the art provided with the details described herein will know how the photomask layout of this embodiment should be adjusted for other cases.

  As shown in FIG. 10a, the waveguide is down-tapered and squeezed before being up-tapered and expanded toward region 20. FIG. Down-tapering can firstly reduce the thickness of each optical resizing element, and secondly allows separation between parallel waveguides to reduce or eliminate crosstalk. Is advantageous.

In embodiments where regions 18 and 20 are parallel and located on opposite sides of the layer, the thickness of device 30 is primarily determined by the waveguide separation distance S _y . See FIG. 10b. The thickness can be approximated by the formula 0.5S _y (N ₁ + N ₂ ). Where N ₁ × N ₂ is the number of waveguides (eg, if device 30 is used for image resizing, N ₁ × N ₂ may be the number of pixels in the image).

  In embodiments where regions 18 and 20 are located on adjacent sides of the layer (eg, substantially orthogonal, see FIG. 4e above), the thickness of the optical resizing element is determined by the input pixel array size. If waveguide bend 48 (not corner mirror 50) is used, the bend radius needs to be added to the overall thickness of the element. However, as described in more detail below, it is preferable to add parasitic losses to the short waveguide by reducing the bend radius. Thus, the thickness of the device 30 can be determined by the bend radius regardless of the number of pixels / waveguides.

  Also to increase the separation distance of the waveguide along the vertical direction (to eliminate crosstalk), the waveguide can be tapered at the input and output facets in the vertical direction. Due to PLC technology, vertical tapering is a well-known technology (see, for example, T. Bakke et al., “Polymeric optical spot-size transverter and lateral tapes”, J. Light. Tech., Vol. (See 2002). The process for fabricating both vertically and laterally tapered waveguides is illustrated in FIGS. 11a-b for the single waveguide case (FIG. 11a) and for the waveguide stack case (FIG. 11b). Show. Other methods for generating a vertical taper are described by Moerman et al., “A review on fabrications technologies for the monolithic integration of tapes with III-V semiconductor devices. Sel. Topics Quantum Electron. Vol 3, 1308-1320, 1997. Thus, the separation distance of the waveguides in the facets is much smaller than in the entire device, allowing optical coupling to the waveguides (in the facets) and improved efficiency in reducing or eliminating crosstalk between waveguides in the device. Become.

  In a preferred embodiment of the present invention, device 30 receives light from a plurality of light sources. This embodiment has several advantages. First, the thickness of the device 30 can be reduced by using a larger number of light sources. Since the number of parallel waveguides from the input facet to the output facet is reduced, the thickness can be reduced. The thickness reduction rate is equal to the number of input light sources used. For example, in the case of two light sources, the thickness can be halved. Another advantage is that each individual light source can have a lower resolution (fewer pixels) while maintaining the desired brightness. An additional advantage is that the use of multiple light sources can facilitate the generation of a three-dimensional image, as will be described in further detail below. The use of multiple light sources is particularly advantageous when the device 30 is used as a backlight assembly. Thus, the monochromatic light source can be selected according to the desired color channel so that the generated monochromatic light source can propagate into the waveguide to directly illuminate the subpixel positions.

  Light reception from multiple light sources can be accomplished in multiple ways. Thus, in one embodiment illustrated in FIG. 12a, the two light rays 122 and 124 are incident on the first optical resizing element 32 from two different light sources (not shown). A configuration with more than two light sources is also conceivable. In the exemplary description shown in FIG. 12a, element 32 is manufactured in accordance with an embodiment in which regions 18 and 20 (not shown) are collinear, but others will be understood by those of ordinary skill in the art. In this case, several light beams can be input to the element 32, and it is not always necessary to do so. Thus, in the preferred embodiment of the present invention, element 32 includes two input facets designated 40a and 40b, and one output facet 42. If more than two light sources are used, the number of input facets of element 32 is preferably adjusted accordingly (ie three input facets for three light sources, etc.).

  Both light beams exit from element 32 through facet 42 in an expanded state in one dimension and enter element 34 through facet 44, where they are expanded in other dimensions as detailed above. .

  In another embodiment illustrated in FIGS. 12b-c, device 30 is designated 32a and 32b, both designated as two optical resizing elements, and 34, acting as transmissive elements within device 30, and device 30 Including an optical resizing element that functions as a light receiving element. Four rays 122a, b and 124a, b enter elements 32a and 32b and exit from element 34 in conjunction with each other as detailed above. The illustration of FIG. 12b is for an embodiment in which each of the optical resizing elements 32a and 32b is manufactured according to an embodiment in which regions 18 and 20 (not shown) are collinear, and the illustration of FIG. In the embodiment in which each of the optical resizing elements 32a and 32b is manufactured according to an embodiment in which regions 18 and 20 are located on adjacent sides of the layer. All combinations between the above embodiments are also conceivable.

  In the additional embodiment illustrated in FIGS. 12d-f, apparatus 30 receives optical input in the form of a plurality of monochromatic light sources and uses the optical input to generate a resized monochromatic light beam. For example, a plurality of single color images can be enlarged and combined by the device 30 to generate an enlarged single color image.

  In the representative example shown in FIG. 12d, three monochromatic images (eg, a red image, a green image, and a blue image) are transmitted from three monochromatic image sources (not shown), and three optical resizing elements 32a, 32b, And 32c. Each of the elements 32a, 32b, and 32c enlarges the respective monochromatic image in one dimension and transmits it to the element 34. Element 34 enlarges the monochromatic image and combines them in other dimensions to provide an enlarged color image.

  In order to combine monochrome images into a color image, the element 34 is preferably made from an alternating arrangement of layers in which the waveguides of each layer are preferably optimized according to the average wavelength of one monochrome image. Shown in FIG. 12d are three types of layers designated by the numbers 37a, 37b and 37c. Layers 37a, 37b, and 37c can each be optimized for typical average wavelengths of, for example, red, green, and blue monochromatic images. The length of the waveguide is selected depending on the position of elements 32a, 32b, and 32c relative to element 34. FIG. 12e is a schematic view of the alternating layers 37a, 37b, and 37c for red, green, and blue images. This embodiment is advantageous because it reduces or eliminates possible dispersion through the use of wavelength specific waveguides. An additional advantage of this embodiment is that the number of optical elements such as lenses and multiplexers of the image source can be reduced. Thus, instead of incorporating a multiplexer and lens in the input source, the image source is multiplexed with element 34.

  As described above, the elements 32a, 32b, and 32c that receive and transmit a monochromatic image can all be manufactured using similar or identical photomasks. For example, see the photomask shown in FIG.

  As stated, embodiments of the present invention are suitable for non-image optical data as well as image optical data. Therefore, it should be understood that the above reference to image data should not be construed as limiting the scope of the invention in any way. Thus, for example, embodiments of the present invention provide a color for an LCD panel having a stripe matrix of red-green-blue (RGB) light from another display device, eg, three filtered light sources, LEDs, or laser sources. It can be used to provide image or color backlighting.

  Reference is now made to FIG. 45, which is a schematic illustration of a backlight assembly 62 according to various exemplary embodiments of the present invention. The backlight assembly 62 preferably includes a plurality of waveguides 16 formed and / or embedded in one or more substrates. The waveguide supplies illumination light to each subpixel position of the passive display panel 64 (not shown, see FIGS. 43b, 44a and 44b) in such a way that each pixel region 52 is illuminated by two or more waveguides. Arranged to do. In particular, for each pixel region 52 (not shown in FIG. 45, see FIGS. 43b and 44a-b), each waveguide and a portion thereof is one sub-pixel region 52 by a respective color channel at sub-pixel location 54. It is arranged to illuminate pixel location 54 (not shown in FIG. 45).

  An exemplary color distribution of backlight illumination to the panel 64 provided by the assembly 62 is shown schematically in FIGS. In FIG. 46a, the illumination area of each waveguide is approximately equal to the area of the subpixel location illuminated thereby. In FIG. 46b, the illumination area of each waveguide is substantially smaller than the area of the respective subpixel location, thus allowing each subpixel 54 of the panel to be illuminated by multiple waveguides.

The backlight assembly 62 can include any number of substrates. Four such boards are shown in FIG. 45: three input boards 502a, 502b and 502c, and one output board 504. The principles and operation of the waveguides of the substrates 502a, 502b and 502c are similar to the principles and operation of the elements 32a-c described above, and the principles and operation of the waveguides of the substrate 504 are similar to the principles and operation of the element 34. In various exemplary embodiments of the invention, the separation distance t between the layers of the output substrate 504 is adapted to the separation distance between adjacent subpixels associated with the same color channel (along the columns of the passive display panel 64) ( The separation distance Δx between the waveguides of the output substrate 504 in the output region (eg, region 20 in FIG. 4e or 4f) is the separation distance between adjacent subpixels associated with different color channels (along the rows of the passive display panel 64). Fits. Typically, although not required, t = W _c and Δx = H _r , where W _c and H _r are the column-to-column and row-to-row separation distances that characterize the panel 64, respectively.

  Reference is now made to FIGS. 13a-c, which are schematic illustrations of a preferred embodiment device 30 in which there are two or more optical outputs from the device.

  In one embodiment schematically illustrated in FIG. 13a, the optical element 32 transmits light in more than one direction. Shown in FIG. 13a are three optical elements 32, 34a, and 34b, which transmit light to both elements 34a and 34b. Thus, in a preferred embodiment of the present invention, element 32 acts as a transmissive element in device 30 and elements 34a and 34b both act as light receiving elements in device 30. In particular, the light beam 132 is incident on the element 32 and is thereby transmitted in the form of two light beams 134a and 134b. It should be understood that element 32 can transmit more than two (eg, three, four) light beams.

  At least one of the light beams 134a and 134b, more preferably both, are independently resized (eg, expanded) in one dimension relative to the light beam 132. For example, when the beam 132 constitutes an image, the beams 134a and 134b may be a three times magnified image and a two times magnified image of the original image, respectively. Alternatively, if desired, one beam may be a magnified image of the original image and the other beam may be a reduction thereof. Elements 34a and 34b receive light beams 134a and 134b, respectively, from element 32 and resize them in other dimensions, preferably to the same extent as the resizing performed by element 32 to maintain the aspect ratio. Thus, device 30 provides two output light beams 136a (generated by element 34a) and 136b (generated by element 34b), each resized in two dimensions relative to the input light beam 132. .

  In another embodiment schematically illustrated in FIG. 13b, the optical resizing element 34 receives a (expanded) light beam 134 from the element 32 and transmits it in more than one direction. In the representative example of FIG. 13b, element 34 splits the light into two and produces two light beams 136a and 136b that propagate in two opposite directions.

  The embodiment shown in FIGS. 13a-b is such that two optical outputs (beams 136a and 136b) are generated by the same optical element, and both light beams 134a and 134b (see FIG. 13a) are transmitted to element 34. Can be combined.

  In addition, the element 34 can be optically supplied by a plurality of optical elements, each transmitting a different light beam emanating from a different light source to the element 34. A representative example of this embodiment is shown schematically in FIG. 13c. There, there are two light sources (138a and 138b) that transmit light beams 132a and 132b to two optical elements 32a and 32b, which resize the beam in one dimension to generate light beams 134a and 134b, respectively. To do. Element 34 receives light beams 134a and 134b from elements 32a and 32b and expands them in another dimension to produce light beams 136a and 136b, which are in two different directions (opposite directions in this example). introduce.

  14a-b, in a preferred embodiment of the present invention, the apparatus 30 performs one or more additional operations to perform various optical operations and / or facilitate the manufacturing process. An optical element 142 is included. Additional optical elements can be formed from a plurality of waveguides in an expanded or non-expanded arrangement depending on their desired function. In the representative example shown in FIG. 14 b, the additional element 142 is an image rotation element 144. In use, a light beam 146 that constitutes an image is incident on element 144, where the image is rotated, for example, 90 °, and exits element 144 as a rotated light beam 148. Thereafter, light beam 148 is incident on elements 32 and 34, where it is first expanded in one dimension (light beam 150) and then expanded in another dimension (light beam 152), as detailed above. . Image rotation element 144 is particularly useful in embodiments where the optical resizing elements are configured to make their small and large facets substantially orthogonal to each other.

  FIG. 15 is a schematic diagram of a layer (eg, layer 14) of a preferred embodiment optical element, where the layer includes a polarizer 154. The polarizer 154 can be formed, for example, by depositing a metal or alloy (eg, Cr, Au, Al, etc.) in the gap 156 between the waveguides 16 to attenuate the transverse polarization mode. Preferably, the waveguide is made narrow in the region of the polarizer in order to efficiently strip the transverse polarization mode. Using an optical element with a polarizer 154 allows the use of an input light source that produces unpolarized light, or this configuration can improve the polarization state when the light source produces polarized light.

  Polarization is particularly useful when the optical element is used in a backlight assembly for a passive display panel where it is desirable to illuminate the liquid crystal module with the polarization. For such applications, the backlight assembly preferably includes a polarizer 154 that can be incorporated into the layer of the optical element as described above, or it can be located between the light source 172 and the waveguide 16. (See FIG. 43b). The advantage of positioning the polarizer 154 between the light source and the waveguide is to replace the traditionally costly large panel polarizer with a small polarizer sheet. Alternatively or additionally, the light source can be configured to provide polarization, as described above.

  The coupling between the device 30 and the light source can be made by direct contact or alternatively via one or more additional optical elements, such as but not limited to an array of microlenses or diffractive optical elements. it can.

  When the device 30 operates in the display unit of the display device, the optical element receives the light encoded by the image data, and the optical coupling between the device 30 and the light source holds the image constituted by the input light beam. It is preferable to do so. On the other hand, when the device 30 is used as a backlight assembly, the backlight assembly is preferably coupled to a light source that produces uncoded light. In this case, the waveguide can be input in a non-imaged manner. The optical coupling of the device 30 to the image source is presented below, and the optical coupling of non-image light is presented below.

  16a-b are schematic views of the coupling between the device 30 and the light source. Shown in FIG. 16 a are several waveguides 16 of the device 30, an image source 160, and a coupler 162 for providing optical coupling between the device 30 and the image source 160. In this example, the image source 160 is an LCD microdisplay. Coupler 162 preferably includes a microlens array 164 and a polarizer 166. The use of the microlens array 164 is advantageous because the LCD panel typically includes a polarizer and LCD protective glass on the output side, and the microlens array provides better coupling efficiency. The microlens array can be manufactured using any method known in the art, such as the methods disclosed in US Pat. No. 5,508,834 and US Patent Application No. 20040100700.

  With reference to FIG. 16b, the microlens array 164 can also be placed on the input optical element so that each waveguide core is covered with one microlens. For example, see core 161 and microlens 168 in FIG. 16b. This can be done by etching the input facet of the optical resizing element with an etcher that etches the clad 163 of the waveguide 16 at a higher speed than the core 161.

  Alternatively, if the LCD microdisplay includes a sufficiently thin polarizer and protective glass layer, the bonding can be performed without a microlens array, for example by direct contact. For example, when the total thickness of the polarizer and the protective glass is about 20 μm or less and the waveguide of the optical resizing element coupled to the LCD microdisplay has a sufficiently small numerical aperture (for example, about 0.25 or less) It is. Such a configuration can minimize crosstalk between adjacent pixels that may blur the image.

  FIG. 17 is a schematic diagram of a preferred embodiment in which an input image is focused on device 30 using lens 176. With this arrangement, pre-expansion can also be obtained, thus reducing the required aspect ratio of the waveguide or eliminating the need for two-stage expansion, as described in further detail below. This configuration is particularly useful for other input panels such as, but not limited to, a reflective liquid crystal microdisplay such as LCD on silicon (LCOS) or a digital light processor (DLP). Shown in FIG. 17 are a reflective liquid crystal microdisplay 170, an external light source 172, and a device 30. Light 174 from light source 172 is focused on microdisplay 170 by lens 175, which reflects the light. The reflected light constitutes an image therein and is focused on device 30 by another lens 176.

  Pre-expansion can also be performed in only one dimension. By combining the distorted input (enlarged in one dimension) with an optical resizing element, the device 30 in this case does not require two optical resizing elements and is a pre-magnifying element (this should be a lens) However, it is possible to obtain a small thin device.

Reference is now made to FIGS. 18a-b, which are schematic views of the coupling between the device 30 and the light source in a preferred embodiment in which the coupling is performed by fiber bundles. According to a preferred embodiment of the present invention, one (FIG. 18 a) or more (FIG. 18 b) fiber bundle 180 directs light directly to the receiving optical resizing element of the device 30. In embodiments where the device 30 is used to resize an image, the fiber bundle is preferably composed of many fibers with a small core to allow transmission of high resolution images. Expressing the number of rows and columns of the fiber bundle as X ₁ and X ₂ respectively, the total number of fibers in the fiber is X ₁ × X ₂ . Representative examples of X ₁ and X ₂ include, but are not limited to, about 500 to about 2000. X ₁ = X ₂ is preferred but not essential. The diameter of the fiber core is preferably less than 20 μm, more preferably less than 15 μm, for example about 10 μm.

  When the device 30 receives optical input from multiple light sources (see FIG. 18b), each bundle communicates to one optical channel. In the example shown in FIG. 18b, the input fiber bundle 180 feeds four input facets (182a, 182b, 182c, and 182d) of the device 30, respectively, and four fiber bundles (180a, 180b, 180c, and 180d). Separated.

  The apparatus 30 can also receive optical input in the form of a focused light beam, such as a laser beam. Color images can be formed from a plurality (eg, two or more) of monochromatic laser devices, eg, red, green, and blue laser devices that are scanned to form an image. Such an image can be projected onto the input facet of device 30 having a small cross-section. The advantage of using laser light is the high brightness and the ability to calibrate the intensity and position of the laser light spot depending on the transparency and position of the waveguide in the device 30. Suitable transparency optimization procedures according to various exemplary embodiments of the present invention are presented in the Examples section below.

  When device 30 is used as a backlight assembly, there is no or minimal alignment between layers as an input area. In particular, there is no restriction on the gap between layers. Thus, waveguides in different layers can have different thickness clads.

  47a-b are schematic views of a suitable technique for coupling light to the device 30 when the device 30 is used as a backlight assembly. According to a preferred embodiment of the present invention, the waveguides 16 are arranged in each layer such that at the input region 18 the termination portion of each waveguide is substantially collinear with at least one optical path 506 characterizing the light source 172. Is done. This embodiment is particularly useful when a light source with a wide field of view, such as an LED, is used. Collinearity between the optical path and the waveguide can be achieved, for example, by placing the input region according to the characteristic wavefront light of the light source. In the representative example shown in FIG. 47 a, the light source emits light that expands elliptically, so that the input region 18 has an elliptical shape so that the waveguide is collinear with the optical path 506. In another embodiment shown in FIG. 47b, the input region can have a linear shape and each waveguide is shaped and / or oriented differently to achieve the collinearity described above. The waveguides are preferably up-tapered towards the input region 18, and the individual widths of waveguides that are shaped and / or oriented differently can be different to compensate for different power distributions at different angles. preferable.

  As described above in this document, light can be emitted from device 30 at any predetermined angle relative to the emission facet. The predetermined angle may be about 90 °, in which case the waveguide may be formed in a substantially orthogonal relationship to the output facet, or any other angle, in which case The waveguide is tilted with respect to the output facet.

  Reference is now made to FIG. 19, which is a schematic diagram of one layer of one optical resizing element of the device 30 in a preferred embodiment in which the waveguide 16 is inclined relative to the end of the layer. The resulting optical resizing element emits light 194 at an angle θ (designated by numeral 190 in FIG. 19) relative to the output facet.

  In a preferred embodiment of the present invention, device 30 is designed and configured to provide a three-dimensional image. A three-dimensional image can be obtained by generating two different images of two different polarizations or two different colors. The user can then view the image using binocular devices with different polarizations or different colors for each eye, thus mimicking the three-dimensional perception of the image.

  Alternatively, the device 30 can function as an autostereoscopic display, thereby eliminating the need for the observer to wear a dedicated viewing tool to keep the two images separated. Autostereoscopic vision is provided to the user in the form of two different images directed at the left and right eyes of the user. Representative examples of autostereoscopic displays according to various exemplary embodiments of the invention are provided below (see FIGS. 34a-35c and the accompanying description).

  Display devices are typically manufactured under the constraints of “pixel-to-pixel” alignment between photocoupled display panels. In particular, in order for the display device to function properly, the pixels of the light-coupled panel need to be aligned with micron or sub-micron tolerances. It has been recognized that this requirement complicates the manufacturing process and often completely disables the manufacturability of the product. In embodiments of the invention, there is no need for pixel-to-pixel alignment between the input picture image and element 32 or between element 32 and element 34.

  Further, the number of pixels in the picture image may be different from the number of pixels in element 32, which may also be different from the number of pixels in element 34. To do so, it is preferred that the number of pixels (waveguides) of the receiving element is k times larger than the number of pixels (waveguides) of the transmissive element, without reducing the resolution. Here, k is a number greater than 1, for example, about 2, more preferably about 3. For further details, see US Pat. No. 6,326,939, the contents of which are incorporated herein by reference. Thus, there is no need for correlation between the input image pixels and the pixels of device 30, and there is no need to align the waveguides of the two optical resizing elements.

  With respect to misalignment between layers of the same optical element, x micron misalignment between layers is x (M-1) when the large and small facets are opposite and parallel, and xM when the large and small facets are substantially orthogonal. , And if the large and small facets are in the same plane, they are converted to an effective misalignment (in the output) of x (M + 1). Thus, for an output tolerance of about 0.2 mm and a magnification of about 10 times, the layers can be stacked with an accuracy of about 20 microns in the input waveguide region. The need for alignment is not limited to one dimension. In embodiments where the large and small facets are parallel (opposite or in the same plane), there is no need for alignment in the lateral direction. On the other hand, in embodiments where the large and small facets are substantially orthogonal, the lateral tolerance is about x microns.

  A x micron misalignment due to the lack of polarization in the transmissive optical resizing element (eg, element 32) is converted to a xM micron misalignment in the output, where M is the magnification of the light receiving element. The rotational misalignment between the two optical resizing elements is preferably minimized to reduce image distortion.

  Variations in waveguide thickness and width that lead to differences in waveguide transparency can add to the total loss budget of the waveguide. In order to suppress the moire fringe effect, it is preferable that some width and thickness variations can be introduced.

  Reference is now made to FIG. 20, which is a schematic illustration of an optical resizing device 200 in accordance with various exemplary embodiments of the present invention. Similar to the device 30 described above, the device 200 can act as a display unit of a display device or as a backlight assembly. The apparatus 200 includes a plurality of layers 202 that form a substrate 204 having a first facet 206 and a second facet 208. Layers 202 are arranged in a partially overlapping optical arrangement.

As used herein, a “partially overlapping optical arrangement” of layers refers to an arrangement that includes at least one region in which each layer is optically exposed to the surface of the layer. As used herein, an optically exposed area refers to an area that can establish optical communication with the environment. Thus, there is a substantially free optical path between the environment and each layer of device 200, which passes through the surface of the layer and the optically exposed area. Thus, the optically exposed region can emit light directed out of the surface of the layer without being substantially absorbed, reflected, or scattered from adjacent layers. The optically exposed area emits light directed outward from the surface of the layer or is inward toward the surface of the layer without being substantially absorbed, reflected, or scattered from adjacent layers Can receive light. Parameters that can be used to characterize the sequence of layers, for example, FIG. 21a, 21b, 21d, Ni will be shown in 22c and 22f, the exposure is the length _{L e.}

  Figures 21a-b schematically show side views of two partially overlapping optical arrangements according to various exemplary embodiments of the present invention. Shown in FIGS. 21 a-b are layers 202 each having a surface 290 and an end 292. The waveguide 16 is embedded in the layer 202 and extends within each layer from the first region 293 to the second region 294 of the layer, where the first region 293 is preferably the input region, and the second region 294 is the output region. A region is preferred. The waveguides of one or more layers of the device 200 can be arranged such that there are multiple input regions and multiple output regions. This embodiment is particularly useful when it is desirable to reduce the number of layers in device 200. A more detailed description of such an arrangement is given below.

  The second region 294 is optically exposed. Thus, there is a substantially free optical path 296 that passes through the surface 290 and connects the environment 298 with the optically exposed region 294, regardless of the position of the layer in the stack. Accordingly, light 291 propagating in the layer 202 (in the waveguide 16) can exit the layer 202 to the environment 298 via the surface 290.

  In the embodiment shown in FIG. 21 a, region 294 is physically exposed to the environment and thus establishes optical path 296. In the embodiment shown in FIG. 21b, there is an overlap between adjacent layers in region 294 so that optical path 296 passes through the layers. In this embodiment, layer 202 (or at least a portion of each layer) is fabricated from a material that can transmit visible light therethrough so as to retain optical path 296.

  Light is coupled out of the layer through surface 290 regardless of whether the layer terminates in an optically exposed region (as illustrated in FIG. 21a) or extends beyond it (FIG. 21b). Those skilled in the art will understand that this is possible. Suitable configurations for coupling light out of layers according to various exemplary embodiments of the present invention are given below.

When the device 200 is used as a backlight assembly, the exposed length L _e preferably matches the inter-column separation distance W _c and the separation distance Δx between adjacent waveguides of the same layer along the output region 20 is Preferably, the line separation distance H _r characterizing the passive display panel 64 is met. In particular, L _e = nW _c and Δx = mH _r . Where n is an integer and m is any number from about 0.1 to about 10. In various exemplary embodiments of the present invention, for each layer, ensure that the waveguide illuminates all subpixels in each column of panel 64 (and thus illuminates one subpixel per row). Therefore, n = m = 1. Alternatively, the integer n is equal to 2 or more so as to achieve that each layer illuminates light in more than one column (and thus in each row illuminates two or more adjacent sub-pixels in the row). be able to. Different configurations for various choices of integers n and m are given below.

  In a preferred embodiment of the present invention, facet 208 of device 200 is defined by an optically exposed area of the layer. Facet 208 can be inclined or it can have a two-dimensional stepped shape (terrace). Each layer has an extended array of waveguides defined by circumferential boundaries, as detailed above. See, for example, the circumferential boundary 22 in FIGS. 4b, 4e, 4f, and 10a. Similar to element 10 and device 30 described above, a portion, or all, of the waveguides 16 of each layer can be tapered or partially tapered as desired. In addition, an extended array of waveguides 16 can be achieved by waveguide bending and / or corner mirrors, as detailed above, waveguide bending is advantageous in terms of optical loss and corners. The mirror is advantageous in terms of the thickness of the device.

  As will be appreciated by those of ordinary skill in the art, the extended arrangement of waveguides in each layer of device 200 results in a one-dimensional optical resizing as indicated by arrow 210 in FIG. An optical arrangement that overlaps results in another dimension of optical resizing as indicated by arrow 212.

  As shown in the representative example of FIG. 20, the first facet 206 is defined by the end 216 of the overlap region 218 of the layer 202. Figures 21c-d schematically show one (Figure 21c) and several (Figure 21d) layers of the device 200, better showing the end 216 of the unexposed region 218. The exposed area of the layer 202 that forms the facet 208 is indicated by the numeral 220 in FIGS.

  In the alternative embodiment shown in FIGS. 22 a-c, layer 202 is partially exposed at both first facet 206 and second facet 208. In particular, facet 206 (FIGS. 22a-b) is defined by exposed area 222 (FIG. 22c) and facet 208 is defined by exposed area 220. The difference between the above embodiments is that if the facet 206 is defined by the edge of the overlapping region, light exits the device 200 in a direction perpendicular to its incident direction, but the facet 206 is defined by the exposed region. In this case, the light is emitted from the device 200 in parallel (FIG. 22b) or in the opposite direction (FIG. 22a) to its incident direction.

  Referring now to FIG. 22d, it shows that the apparatus 200 includes two optical elements 232 and 234, which provides optical resizing of one dimension (indicated by arrow 212), with element 234 partially FIG. 6 is a schematic diagram of an apparatus 200 in a preferred embodiment that receives a resized light and resizes it in another dimension (arrow 210). Although element 232 is preferably smaller than element 234, it is not essential.

  Elements 232 and 234 can be manufactured in separate manufacturing processes and then optically coupled, or more preferably they can be integrated elements, in which case their optical coupling is performed during the manufacturing process. Can be achieved. In the latter embodiment, each layer of device 200 has two portions 432 and 434 (not shown; see FIGS. 22e-f), where portion 432 is designated for element 232 and portion 434 is designated for element 234. Is done. This embodiment is illustrated more clearly in FIGS. 22e-f, which show a top view of one layer (FIG. 22e) and several layers (FIG. 22f) stacked on top of each other in a partially overlapping optical arrangement. ing. In the layer shown in FIG. 22e, the waveguide extends from the first region 18 to the second region 20, thereby forming a longitudinally expanded array, as detailed above. Also shown in FIG. 22e is a first portion 432 and a second portion 434 designated for elements 232 and 234, respectively, as described. Once the layers are stacked, element 232 is formed from portion 432 and element 234 is formed from portion 434.

  In embodiments where the optical elements are manufactured in a separate manufacturing process, each of the elements 232 and 234 can be manufactured independently for each layer or as a mass, as described in further detail below (FIG. 26-27h and accompanying description). In a preferred embodiment of the present invention, element 232 acts as a transmissive element in apparatus 200 so that light incident on element 232 through facet 236 passes through element 232 through facet 238 located at the interface between elements 232 and 234. Communicated by In this embodiment, the element 234 acts as a light receiving element in the device 200 and light transmitted by the element 232 is received by the element 234 via the facet 240 that is also located at the interface between the devices. After being resized in dimension 210, the light exits element 234 through facet 242.

  In the exemplary configuration shown in FIG. 22d, the optical element 234 is manufactured according to the principle of partially overlapping optical arrangements as detailed above, with the exposed portions of the layers forming facets 242. Similar to facet 208 above, facet 242 can be tilted or can have a terrace shape. Also shown in FIG. 22d is an expansion structure 224 that is optically coupled to facet 242 in a preferred embodiment of the present invention. The expansion structure 224 serves to expand light rays passing therethrough, as will be described in further detail below.

  As will be appreciated by those of ordinary skill in the art, the extended array of waveguides in element 232 results in an optical resizing of dimension 212, and the terrace or slanted facet 242 of element 234 results in a dimension 210. Provides optical resizing. The cladding layer of device 200 can be made from an absorbing material or a non-absorbing material, as desired. The advantage of using an absorbing material is that the contrast is improved, and the advantage of using a transparent material is that it makes it possible to produce a transparent display that does not block the scene behind. In addition, a polarizer can be added between the cores of the waveguide as detailed above (see FIG. 15).

  The coupling of light out of the partially overlapping optical arrangement of the present invention can be accomplished in a number of ways. Roughly speaking, an optical redirecting element is used to redirect light out of the waveguide. The redirecting element can be operated on any optical principle including reflection, refraction, diffraction and any combination thereof.

  Thus, in one preferred embodiment, light is coupled out of facet 208 using an array of reflective elements. In this embodiment, the light propagates in the waveguide substantially parallel to the surface of the layer until it strikes the reflective element and the light is redirected out of the surface. In another embodiment, light is coupled out of facet 208 using an array of transmissive elements (eg, waveguides, transmissive diffractive elements, etc.). A combination of a reflective element and a transmissive element is also possible. Representative examples of optical redirecting elements suitable for embodiments of the present invention include, but are not limited to, mirrors (eg, total internal reflection mirrors, etched mirrors, coated mirrors, planar facet mirrors, non-planar facet mirrors) , Wedge structures (for example, diffractive wedge structures), Bragg reflectors, holographic optical elements, and the like.

The number of redirecting elements can vary from one to multiple redirecting elements per waveguide. When the layers of device 200 have one redirecting element per waveguide, each such waveguide emits light from a single location along the waveguide in the optically exposed region of the layer. In this embodiment, when the device 200 is used as a backlight assembly, the light emitted by each such waveguide illuminates a single subpixel location of the passive display panel. When a layer of the device 200 has more than one redirecting element per waveguide, each such waveguide emits light from two or more spaced locations along the waveguide in the optically exposed region of the layer. discharge. In this embodiment, when the device 200 is used as a backlight assembly, the light emitted by each such waveguide illuminates a plurality of sub-pixel locations along a row of passive display panels. Thus, according to a preferred embodiment of the present invention, the separation distance between the spaced light emitting positions is substantially equal to the inter-row separation distance H _r characterizing the passive display panel. The use of multiple redirecting elements per waveguide is also useful when multicolor (eg, white) light propagates in the waveguide of the backlight assembly. In this embodiment, the light emitted by each such waveguide illuminates a plurality of sub-pixel locations or pixel areas along the columns or rows of the passive display.

  The following is a more detailed description of a suitable technique for coupling light out of the waveguide. Embodiments in which light is coupled out through reflective, diffractive and / or refractive elements are first described, and embodiments in which light is coupled through an array of transmissive elements and various combinations of reflective and transmissive elements. It describes after that (refer FIGS. 26-27h).

  Referring now to FIGS. 23a-b, they are a side view (FIG. 23a) and top view of a portion of facet 208 of apparatus 200 in a preferred embodiment where facet 208 has a two-dimensional stepped shape (terrace). It is the schematic of (FIG. 23b). Reference is also made to FIGS. 23c-d, which are schematic views of mirrors 282 disposed in the layers of apparatus 200, according to a preferred embodiment of the present invention.

  As shown in FIGS. 23a-b, a small number of mirrors 282 (eg, total internal reflection mirrors) with different reflectivities are preferably placed in the reflective region 283 of each layer 202 of the device 200. Mirror 282 collects the light propagating in the layer and redirects it to couple the light out of facet 208. Propagating light and redirected light are designated by numerals 284 and 286, respectively, in FIGS. The mirror 282 is preferably wide in order to optimize light collection and coupling. By providing mirrors with different heights, mirrors 282 with different reflectivities can be realized.

  Alternatively, the mirror 282 can be narrowed without variations in reflectivity so that light impinging on the mirror is completely reflected. In order to facilitate efficient collection of light 284, the mirror 282 is preferably disposed substantially uniformly throughout the reflective region 283. Such a configuration results in a substantially uniform reflection of light out of facet 208. As shown in the top view of facet 208 (FIG. 23b), redirected light 286 can be further expanded in two dimensions when impinging on the boundary between facet 284 and the external medium. Such expansion generally occurs when facets 284 are coated with a protective coating such as but not limited to glass or polymer, or when light is coupled downward as shown in FIG. 33b. . The redirected light before and after being expanded on the protective coating is shown in FIG. 23b by rectangle 286 and circle 288, respectively.

  Further alternatively, both methods can be combined, for example by placing a narrow partially reflecting mirror over the entire terrace surface. The mirror can be made in the polymer waveguide, for example by a molding or ablation process.

  In connection with FIGS. 23c-d, the mirror 282 can have a planar (FIG. 23c) or non-planar (FIG. 23d) shape. For applications where a narrow or moderate field is required, a plane mirror is preferred and can be obtained, for example, using a series of laser ablation pulses. For applications where the required field of view is wide, non-planar mirrors are preferred and can be obtained, for example, using a small number (eg, one) of laser ablation pulses.

  Reference is now made to FIGS. 48a-d, which are schematic views of an optical redirecting element 508 of a preferred embodiment of the present invention, in which the optical redirecting element 508 is a partially reflective element. The light 284 propagating into the waveguide 16 branches in two at the element 508 so that the first portion 286 is redirected out of the waveguide 16 while the second portion 287 continues to propagate in the waveguide 16. To do.

  In the schematic of FIG. 48a, element 508 is a non-limiting reflective or diffractive element such as a wedge structure or a Bragg grating, which only partially occupies the cross section of waveguide 16. In this embodiment, the redirecting portion 286 reflects from the element 508 and the non-directing portion 287 passes through the gap between the element 508 and the waveguide 16. The relative amount of reflected and transmitted light depends on the size of the gap between element 508 and waveguide 16. In general, small gaps correspond to high reflection and low transmission, and vice versa.

  In the schematic of FIG. 48b, element 508 includes a region characterized by a refractive index that is different from the refractive index of the core. In this embodiment, the redirecting portion 286 is reflected by the element 508 while the non-reflecting portion 287 is refracted through the element 508. The relative amount of reflected light and transmitted light depends on the difference in refractive index. In general, small differences correspond to low reflection and high transmission, and vice versa. The tilt pattern of element 508 can be achieved, for example, by shaping the waveguide with a wedge pattern, depositing a thin layer of material of different refractive index into the recess, and refilling the recess with a core index material. The tilt angle of element 508 relative to the waveguide axis is not limited and can be any acute angle.

  In the schematic of FIG. 48 c, the element 508 is located in the cladding 266 of the waveguide 16. In this embodiment, the turning portion includes a turning evanescent wave (perpendicular to the plane of FIG. 48c) and the non-turning portion 287 includes a main propagating beam guided into the core. The relative amount of redirected light and transmitted light depends on the width of the waveguide and the distance of the reflective element from the core. FIG. 48 d schematically illustrates an embodiment in which the element 508 includes a translucent wedge structure that is angled relative to the waveguide 16 so that there are two redirecting portions of light. One part designated by 286a is reflected in one direction and the other part designated by 286b is refracted in another direction. In this embodiment, the substrate 12 is preferably coated with a reflective coating 548 so that one of the redirecting portions is reflected and exits the waveguide from the same side as the other redirecting portion. The relative amount of redirected light and transmitted light depends in particular on the reflectivity of the coating 548. When the waveguide has multiple elements 508, the inventive coating 548 preferably has a gradually increasing reflectivity to achieve a substantially uniform optical output.

  The advantage of a partially reflecting element is that the redirecting part can be polarized. This is useful when the device 200 is used as a backlight assembly where it is desirable to illuminate a liquid crystal module with polarized light. Thus, a partially reflective element can be used in place of the back polarizer. For example, for a refractive index difference of 0.05 between the core and the redirecting element (see, eg, FIG. 48b), the reflective portion from a slot located at 45 ° is polarized to a ratio of 30 dB.

  FIG. 48e schematically illustrates an embodiment in which the cladding 266 of the waveguide 16 is shaped such that light is focused by the cladding 266 following its turning. This embodiment can be used for any type of redirecting element. The cladding 266 can be shaped by etching or molding to achieve the desired scattering or focused shape.

  Reference is now made to FIGS. 24a-e, which are schematic side views of an optical element 234, according to various exemplary embodiments of the present invention. The layer 202 of the element 234 serves to facilitate two purposes: (i) coupling light out of the element 234 and (ii) optical resizing (extension in this example) of dimension 210. Propagating light and outgoing light are designated by numerals 246 and 247, respectively, in FIGS. Also shown in FIGS. 24a-e are typical pixel or sub-pixel sizes that characterize the outgoing light 247. FIG. In FIGS. 24 a-e, the pixel size is specified by the number 249.

  The coupling of light out of element 234 can be accomplished in a number of ways. In one embodiment shown in FIGS. 24a-b, layer 202 includes a mirror 248 positioned at the end of the waveguide to redirect light 246 propagating through the waveguide. The mirror 248 may be a 45 ° mirror, a total internal reflection (TIR) mirror, a total reflection or a partial reflection mirror, and as detailed above, they can have a planar or non-planar shape. In addition, the mirror can be coated with a highly reflective material. FIG. 24a shows a preferred embodiment using a 45 ° mirror and FIG. 24b shows a preferred embodiment using a TIR mirror.

  In another embodiment, shown in FIG. 24c, a groove 250 is formed in the layer 202 to force total internal reflection, and thus the redirection of light out of the layer. In an alternative embodiment shown in FIG. 24 d, element 234 includes a Bragg reflector 261 that redirects the light beam out of element 234. In yet another embodiment, the element 234 includes a holographic optical element 263 that is designed and configured to redirect light rays out of the element 234.

  Element 234 can be manufactured as part of element 232, in which case the layers forming the element are made from a single substrate, for example using a photomask of the type shown above in FIG. 21c. More preferably, each layer can be processed with a different mask to reduce potential vertical coupling. Such a manufacturing process also reduces the length of the waveguide that can utilize a single inclined path (not two vertical paths). The layers can be made to their exact length and then laminated to form facets 242, or they can be first laminated to form facets 242, and then polished or ground to form facets 236. Can be formed.

  The element 234 also forms a partially overlapping optical arrangement where the facets 242 have an inclined or terrace shape, for example by laminating layers with waveguides substantially parallel to each other up and down. It can also be manufactured as a separate unit.

  In a preferred embodiment of the present invention, the layers of device 200 are made from a polymeric material, more preferably from a flexible polymeric material, to facilitate the flexibility of device 200. Further, the layers of the device 200 can be bonded to each other on one side (eg, the input side) while being separated on their opposite side (eg, the output side). In such a configuration, the device 200 can be made foldable. A representative example of a foldable device is shown in FIG. 25, showing the device 200 with layers 202 bonded on their input side 251 and separated on their output side 255. In a preferred embodiment where the device 200 is manufactured as two separate elements 232 and 234, which are subsequently bonded, by fully bonding the layers of element 232 and partially bonding the layers of element 234 Can make it bendable.

  Reference is now made to FIGS. 26a-b, which are a simplified side view (FIG. 26a) and a simplified assembly exploded view (FIG. 26b) of a preferred embodiment in which light is coupled out through an array of transmissive elements. . With reference to FIG. 26 a, the optical element 110 has a first facet 112 and a second facet 114 that is inclined at an angle β and is therefore larger than the facet 112. Element 110 has a plurality of waveguides 16 extending from facet 112 and bent toward facet 114, thus providing optical resizing along direction 115.

In the exemplary configuration shown in FIG. 26 a, the waveguide 16 reaches the facet 114 at an angle ψ that is convenient to define relative to the facet normal 116. ψ can have any value that allows optical communication between the element 110 and the environment and provides optical resizing. In general, optical communication and optical resizing can be achieved at any time in an environment where ψ is any value below an angle ψ _C. Preferably, ψ is approximately zero, in which case the waveguide 16 reaches the facet 114 approximately perpendicularly.

  A bent waveguide can be manufactured, for example, according to the principle of the element 10 described above. For example, referring to the exploded view of FIG. 26b, trapezoidal or similarly shaped layers are stacked one above the other so that their surfaces 117 substantially overlap and their ends 119 form inclined facets 114. Can be done. Thus, light propagates in the layer (in the waveguide) and exits the layer through the end 119.

  Element 110 can be optically coupled with any of the above optical elements so as to provide two-dimensional optical resizing. For example, element 110 can be replaced with element 34 of device 30 or element 234 of device 200.

  FIGS. 27 a-b schematically illustrate another suitable manufacturing process for the element 234. In this embodiment, element 234 is processed by alternately stacking sheets of high and low index materials to form stack 231 prior to forming waveguide 233 therein. Thereafter, the stack 231 is obliquely cut to form the inclined facet 242. Once facets 242 are created, individual waveguides 233 are formed in stack 231 by etching grooves 235 therein. In order to prevent etching that is too deep, the process can be performed in batches of, for example, tens or hundreds of layers, and the grooves can be etched in batches. Therefore, the manufacturing process preferably includes four steps, creating a batch of layers stacked in the first step, etching the batch in the second step to form grooves therein, and interconnecting the batches in the third step. In a fourth step, the stack of batches is cut along diagonal lines to form inclined facets 242.

  The groove 235 that separates the waveguides of each layer can be filled with a filler whose refractive index is lower than that of the waveguide (high refractive index material). If desired, the difference between the refractive index of the filler and the waveguide is preferably large (eg, about 0.1 or greater) to provide a wide field of view on the output side of the element 234. In order to reduce scattered light, the filler preferably has enhanced light absorption properties. A typical example of such a material is a low refractive index polymer with a black tone added thereto, but is not limited thereto. Alternatively, the groove 235 can be left untreated, in which case the waveguides are separated by air.

  Additional manufacturing processes for the device 200 will be described later (see FIGS. 29a-e below).

  Reference is made to FIGS. 27c-h, which are schematic illustrations of an expansion structure 224, according to various exemplary embodiments of the present invention.

  As described above, the structure 224 serves to expand the light beam passing therethrough in addition to or as an alternative to the optical resizing provided by the element 232. Thus, in a preferred embodiment using structure 224, apparatus 200 may or may not include optical element 232.

  In connection with FIGS. 27c-e, in the preferred embodiment shown in FIG. 27c, structure 224 includes a stack of patterned layers, and in the preferred embodiment shown in FIG. In the preferred embodiment shown in FIGS. 27e-f, which includes a formed and grooved bulk waveguide material, the structure 224 is striped in an expanded array, similar to the configuration and operation of the optical element 10 (see FIG. banded) including a stack of layers of waveguides. An anti-reflective coating or index matching material 254 can be added between the facet 242 and the structure 224 to reduce reflection at the interface between the element 234 and the structure 224.

  In the latter embodiment (FIGS. 27e-f), the shape and material of the element 234 and structure 224 causes the guided light to bend toward the inside 275 of the facet 242 while the scattered non-guided light propagates in its original direction. Subsequently, it is preferably selected to strike the inside 275 of facet 242 at an angle that is higher than the critical angle of total internal reflection. As will be appreciated by those of ordinary skill in the art, if non-guided light is not emitted from facet 242, device 200 is less sensitive to contrast degradation due to non-guided light.

  Thus, in a preferred embodiment of the present invention, scattered light is not emitted from facet 242. In another embodiment, the waveguide of structure 224 has a higher refractive index compared to the waveguide of element 234. By this method, the aspect ratio (clad layer width to thickness) of the element 224 can be relaxed. The element 234 shown in FIG. 27f is composed of a layer of core material and a layer of cladding material. By depositing but not etching, a cladding layer can be made that can be made much thinner than the core layer. In the embodiment shown in FIG. 27e, the structure 224 is composed of a thick layer with a wide core and a relatively wide cladding barrier. Since it is difficult to produce a clad barrier that is too narrow in a thick layer, it is preferable to increase the width of the waveguide (and the barrier).

In the preferred embodiment of the present invention, the spatial and optical parameters of element 234 and structure 224 are selected to satisfy Snell's law. Specifically, N ₁ sin θ ₁ = N ₂ sin θ ₂ and W ₁ / W ₂ = sin φ ₁ / sin φ ₂ , where N ₁ and N ₂ are the refractive indices of the waveguides of element 234 and structure 224, respectively. , W ₁ , W ₂ are the layer thickness of the element 234 and the layer width of the structure 224, φ ₁ is the tilt angle φ ₁ of the facet 242, and φ ₂ is the band angle of the waveguide of the structure 224 ( banding angle), θ ₁ = 90 ° −φ ₁ , and θ ₂ = 90 ° −φ ₂ . As a numerical example, if N ₁ = 1.50, φ ₁ = 5.7 °, N ₂ = 1.7, the ratio between W ₂ and W ₁ is W ₂ / W ₁ = 4.8. .

  If the waveguides of element 234 are separated by grooves (not formed in individual layers; see FIGS. 27a-b and accompanying description), structure 224 is manufactured using the same technique. Is preferred. An advantage of this embodiment is that light loss at the interface between element 234 and structure 224 can be reduced. In addition, by using an etching technique, a high refractive index contrast is maintained. Thus, in a preferred embodiment of the present invention, structure 224 is fabricated and attached to stack 231 prior to etching (see FIGS. 27a-b). Thereafter, the stack 231 and the structure 224 are etched to form grooves. Within structure 224, low spatial modes (perpendicular to the grooves) are induced between the cladding layers, and high spatial modes are induced between the grooves.

  In the embodiment shown in FIGS. 27g-h, the structure 224 includes a stack 256 of layers 258 having a high index region 252 and a low index region 253. The region may be a rectangular parallelepiped or may have any other geometric shape. Light propagates through region 252 substantially perpendicular to layer 258. The lower layer of structure 224 (designated as layer 258a) is a high index cuboid terminated by a mirror 260 (eg, a TIR mirror) that is preferably not curved to enhance beam divergence by structure 224, but is preferably curved. It is an array. In order to reduce alignment tolerance requirements, regions 252 of other layers 258 of structure 224 are preferably larger than regions 252 of layer 258a. If the mirror is made of metal or coated with metal, the space between element 234 and structure 224 should be filled with a low refractive index filler to reduce back reflection and beam divergence. Is preferred. Within the layer of structure 224, the space between regions 252 can be filled with an absorptive black material to reduce scattered light and improve display contrast. Optical coupling between element 234 and structure 224 can also be achieved by providing a waveguide with a sloping end in element 234 (see FIG. 27h).

  Referring now to FIGS. 28a-c, they are a schematic top view (FIG. 28a-b) and a schematic side view (FIG. 28c) of the layers of the device 200 in a preferred embodiment where the layers are lightweight layers. ). FIG. 28a is a top view of layer 202 of one optical element (element 232, element 234, or both elements 232 and 234 in embodiments where they have a common layer). As shown in FIG. 28a, the waveguides 16 are only partially tapered at their ends 262, and the cross-section does not change substantially along most of their length. In the preferred embodiment of the present invention, the waveguide 16 is coated with a thin layer 264 (not shown; see FIG. 28c) of a low refractive index cladding material, leaving the remaining space substantially empty. Can do. Such a configuration can also reduce the weight of each layer and thus the weight of the device 200. For the purpose of construction, it is preferable to place a support member 260 between the waveguides 16 in order to maintain the planar shape of each layer and prevent layer collapse. The support member 260 can be made of a short section waveguide that is made parallel to the entire waveguide. The member 260 can have any geometric shape (eg, a cuboid).

  FIG. 28 b is a top view of the layer 258 of the expansion structure 224. Similar to the layer 202, the high refractive index regions 252 of the structure 224 can be spaced apart to reduce the weight of each layer of the structure 224. In order to maintain the planar shape of each layer of the structure 224 and prevent collapse, a support member 260 can be disposed between the regions 252.

  FIG. 28c is a side view of layer 202 or 258 showing member 260 positioned between adjacent light transmissive elements (waveguide 16 or high index region 252). FIG. 28 c also shows a preferred configuration for each individual layer in which the light transmissive element is formed on the lower cladding layer 266 and covered by the upper cladding layer 264.

  Another way to reduce the overall weight of the device 200 is to minimize the free space in each layer by manufacturing the layers in the shape of the circumferential boundary 22, as shown above in FIG. 21c.

  Reference is now made to FIGS. 29a-e, which are schematic illustrations of suitable folding techniques for manufacturing an apparatus 200 according to various exemplary embodiments of the present invention. The folding technique is advantageous for applications where it is preferred to produce rectangular layers, for example to facilitate mass production of layers. The folding technique can also be used to manufacture any part of the device 200. In particular, folding techniques can be used to produce devices that provide one-dimensional or two-dimensional optical resizing. In the representative example shown in FIGS. 29a-e, the folding technique is such that an extended array of waveguides in each layer provides a first dimension of optical resizing and partially overlapping optical arrays provide a second dimension of optical resizing. Used to fabricate an optical element configured to provide two-dimensional optical resizing.

  As described herein above, the layers of device 200 are preferably formed from a flexible polymer. In addition, the layers are preferably made thin enough so that they can be folded. Once the rectangular layer is formed, it is folded (with a radius of curvature possible with the polymer waveguide so as not to increase bending loss) to form a predetermined angle of about 90 °. Thus, the folded layer includes an extended array of waveguides where the input region is smaller than the output region. A representative example of a folded layer 270 having an input region 273 and an output region 271 is shown in FIG. 29a, and selected steps of the manufacturing process are shown in FIGS.

  Shown in FIGS. 29 a-d are a folded layer 270 (FIG. 29 a) having an input waveguide 280 and an output waveguide 276, and the output waveguide 274 of layer 272 aligned with the output waveguide 276 of layer 270. (FIG. 29 c) is an additional layer 272 (FIG. 29 b) added to the folded layer 270. Layer 272 is then folded so that the input waveguide 278 of layer 272 is aligned with the input waveguide 280 of layer 270 (FIG. 29d). As a result, a top view of the arrangement of partially overlapping layers is shown schematically in FIG. 29e, showing exposed regions 220 and overlapping regions 218.

  It should be understood that the fabrication process can be performed in the reverse order. In this embodiment, the input waveguide 280 of layer 270 is first aligned, and then the output waveguide 274 of layer 272 is aligned.

  Figures 30a-b are schematic illustrations of simultaneous processes for manufacturing optical elements in various exemplary embodiments of the invention. FIG. 30a shows a top view of a layer 300 that can be used to form four optical elements. Once the layers 300 are created, they are stacked and cut along a vertical path 306 to form two stacks 302 of layers (see FIG. 30b). Thereafter, the stack 302 can be cut along an inclined path 304.

  Reference is now made to FIG. 31, which is a schematic illustration of an apparatus 200 in a preferred embodiment in which the apparatus 200 receives light from multiple sources. In the representative example shown in FIG. 31, device 200 receives optical input from four light sources (not shown). Device 200 includes two optical elements designated 132a and 132b, both serving as transmissive elements in device 200, and one optical element designated 134 and serving as a light receiving element in device 200. Element 134 includes a sloped or terraced facet 242 and is optically coupled to both elements 132a and 132b. The principles and operation of elements 132a and 132b are similar to the principles and operation of elements 32a and 32b described above, with the changes necessary for coupling to tilt element 134. Two light beams are incident on each of elements 132a and 132b (beams 310a and 311a are incident on element 132a and beams 310b and 311b are incident on element 132b). The light beams are transmitted from the elements 132a and 132b to the element 134 and are jointly emitted from the element 134 as an extended light beam 314.

  Referring now to FIGS. 32a-b, they are schematic top views of a preferred embodiment apparatus 200 (FIG. 2) in which the apparatus 200 receives optical input in the form of multiple (eg, two or more) monochromatic light sources. 32a) and a schematic cross-sectional view (FIG. 32b). The optical input provides a magnified color image to illuminate each sub-pixel position of the passive display panel 64 with a respective color channel, as described in further detail above, or using, for example, a plurality of monochromatic images. Therefore, it can be used to generate a resized colored light beam. 32b is a cross-sectional view taken along section AA 'of FIG. 32a.

  In the representative example shown in FIGS. 32a-b, the device 200 includes a plurality of layers 320 in a partially overlapping optical arrangement and an inclined shape as detailed above, forming three input facets 326a, 326b, and 326c. Or one output facet 328 having a terrace shape. Layer 320 can be manufactured using a bending technique or using any of the other techniques described above. Although FIGS. 32a-b describe an embodiment in which a single element (waveguide stack) achieves two-dimensional optical resizing, an embodiment using two optical elements (eg, elements 132 and 134 above). It should be understood that there is no intention to exclude.

  Referring now to FIGS. 32a-b, three monochromatic optical inputs 322 (eg, RGB inputs) are communicated to the apparatus 200 from three color image sources (not shown). The layers 320 of the device 200 are preferably arranged in an alternating arrangement in which the waveguides in each layer are optimized according to the average wavelength of one monochromatic input. Thus, for example, the first type layer 320a is optimized for red light, the second type layer 320b is optimized for green light, and the third type layer 320c is optimized for blue light. Is done. The layers are coupled to different monochromatic light sources according to their wavelength optimization. Alternatively, one or more layers of the device 200 can be designed to guide and emit more than one color channel. The advantage of guiding and emitting one color channel per layer is low crosstalk between the color channels, and the advantage of guiding and emitting more than one color channel per layer is a small number of layers. Regardless, each layer couples light out of the device 200 using a mirror 324 (eg, a TIR mirror) or using any other method as detailed above. The mirror 324 can also be optimized for the average wavelength of the corresponding optical input.

  As described above, the embodiment of the present invention is suitable not only for image optical data but also for non-image optical data. In particular, embodiments of the present invention can be used to provide a color image or color backlighting for another display device, as detailed above. A preferred configuration of the layer that guides and emits one color channel is described first, followed by a preferred configuration of the layer that guides and emits multiple color channels.

When the device 200 is used as a backlight assembly, the exemplary configuration shown in FIG 32a~b is exposed length L _e is equal to inter-column separation distance W _c, therefore per row each waveguide layer It is preferably configured to illuminate one subpixel. A suitable layer design for this embodiment is shown in FIG. 49a. As shown, according to a preferred embodiment of the present invention, the waveguide 16 and the optical redirecting element 508 allow light to enter the layer at the input region 293 and propagate to the waveguide 16 from the output region 294 of the layer. Arranged to be able to exit.

  A suitable layer design for a configuration in which the layer waveguide illuminates more than one subpixel per row is schematically illustrated in FIG. 49b. In this embodiment, the waveguide 16 in the layer generally extends from the input region 293 to the two output regions 294a and 294b, and there are two exit locations of the regions 294a and 294b for each entrance location of the light in the region 293. To do. In the exemplary configuration shown in FIG. 49b, the waveguide is branched downstream light propagation to facilitate light propagation from a single input region to two output regions, but that is not the case. There is no need and other configurations are possible. For example, each waveguide is assigned with two redirecting elements (ie, those in region 294a and region 294b). Alternatively, one waveguide can extend from region 293 to region 294a and another waveguide can extend from region 293 to region 294b. It should also be understood that the scope of the present invention is not intended to be limited to one input region and two output regions. In particular, each layer of device 200 may have any number of input / output regions.

FIG. 50 schematically shows a side view of the apparatus 200 of the preferred embodiment where there are two outlet positions (one for each output region) at each inlet position. In this embodiment, equal to W _c for some exposed length layer is preferably equal to 4W _c for the other layers. In particular, every third layer (i.e., third, sixth, layer, such as 9) is _L e = 4W _c relative to an _L e = _{W c} for all other layers. Such a choice of exposure length ensures that each layer waveguide illuminates the subpixel positions of two adjacent pixel regions per row by a respective color channel.

  The layers of device 200 are better shown in FIGS. 33a-c, which schematically illustrate the coupling of light out of the layers. Shown in FIGS. 33a-c are layers 331 arranged in a partially overlapping optical arrangement. Each layer terminates in a mirror 333, preferably a TIR mirror, so that light 335 propagating in the layer 331 is redirected by the mirror 333 and coupled out of the layer.

  Depending on the orientation of the mirror 333, the light 335 may exit through the free side 337 of the reflective region 345 of the layer (see FIG. 33a) or through the side 339 of the reflective region 345 engaged by an adjacent layer. Yes (FIGS. 33b-c). The embodiment shown in FIG. 33a is referred to herein as forward optical coupling, and the embodiment illustrated in FIG. 33b is referred to herein as backward optical coupling. In configurations where the layer has a substantially uniform thickness and the overall thickness of the layer in the radiating region of the device 200 is small (typically less than 10 mm, such as but not limited to about 2 mm) Back light coupling is preferred. The advantage of back light coupling resides in a simpler manufacturing process and simple deposition of the (high reflection) coating on the mirror. The mirrors can be created during or after the creation of the waveguide, or they can be created in a single step after several or all layers are laminated.

  In a preferred embodiment of the present invention, the apparatus 200 includes a translucent plate 341 disposed obliquely on the layer 331. In addition, the gap between the layer 331 and the plate 341 can be filled with an index matching material 343 so that the light 335 is coupled to the plate 341 substantially perpendicularly out of the device 200. Plate 341 is particularly useful in back light coupling embodiments where backside roughness can degrade light output coupling.

  The following is a description of a preferred embodiment of the present invention in which the layers of device 200 guide and emit multiple color channels. The explanation given above for the coupling of light out of a single color channel layer applies to the embodiments described below for a multi-color channel layer, mutatis mutandis. . Thus, forward light coupling and backward light coupling are considered as described above and shown in FIGS. Furthermore, the translucent plate can be arranged in a tilted orientation on the layer with or without filling of the index matching material.

  51 is a schematic diagram of a single layer 550 of device 200 that includes a plurality of first waveguides 510 (three in this example), each extending from an input region 293 and branching to a plurality of second waveguides 512. FIG. is there. Waveguide 512 extends to output region 294 and is terminated by redirecting element 508, as described in further detail above. In the representative diagram of FIG. 51, each of the three first waveguides receives three color channels and allows propagation of the color channel therein. Light from the first waveguide 510 is distributed to the second waveguide 512. Thus, when device 200 is used as a backlight assembly, light exiting the layer from region 294 illuminates a row of sub-pixel locations on the passive display panel. The advantage of the configuration shown in FIG. 51 is that the number of entry points for optical input into the layer is less than the number of exit points. Another advantage of this configuration is that the required number of layers is significantly reduced.

Figures 52a-b schematically illustrate another preferred embodiment for guiding multiple color channels in a single layer. In this embodiment, each color channel is coupled out of the layer from a different output region. In the representative view of FIG. 52a, each first waveguide 510 extends from the input region 293 to one of the three input regions 294a, 294b and 294c, where light is coupled out of the layer via the redirecting element 508. . FIG. 52b schematically shows a side view of multiple layers of the type shown in FIG. 52a. According to a preferred embodiment of the present invention, when the device 200 is used as a backlight assembly, the exposed length Le is equal to W _c for some layers and nW _c ( However, n is preferably an integer). In the representative example shown in FIG. 52 (which should not be considered as a limitation), Le = 21W _c for every seventh layer (ie, the seventh, fourteenth, twenty-first, etc. layers); Le = W _c for all other layers. Such ordering ensures continuous RGB illumination of the passive display panel 64. The advantage of the configuration shown in FIG. 52a is to avoid crossing waveguides in the layers.

  Figures 53a-b schematically illustrate additional preferred embodiments for guiding multiple color channels in a single layer. In this embodiment, the layer includes a waveguide 16a extending from the first input region 293a to the first output region 294a and a waveguide 16b extending from the second input region 293b to the second output region 294b. The first color channel (eg, red light) enters region 293a and is emitted from region 294a, while the second color channel (eg, blue light) enters region 293b and is emitted from region 294b. According to a preferred embodiment of the present invention, the first color channel propagates in the waveguide 16a and the second color channel propagates in the waveguide 16b. FIG. 53b is a cross section taken along section line AA ′ of FIG. 53a. Propagating light and redirecting light are designated in FIG. 53b by numerals 284 and 286, respectively. The redirecting element 508 couples the propagating light out of the waveguide 16.

  The arrangement of the waveguide 16 shown in FIG. 53a can also be adapted so that there are more than two output regions, for example by the configuration shown in FIG. 49b.

  Accordingly, FIGS. 54a-b show waveguide 16a whose layers extend from first input region 293a to two output regions 294a and 294c, and waveguide 16b that extends from second input region 293b to two other output regions 294b and 294c. 1 is a schematic diagram of a preferred embodiment including As shown in FIG. 54a, each waveguide is branched into two redirecting elements 508, thus allowing light propagating in the waveguide to be coupled out of the layer from a spaced location. Similar to the embodiment shown in FIG. 53a, one color channel enters the layer at the input region 293a and another color channel enters the layer at the input region 293b. Thus, these exemplary configurations support the transmission of two color channels.

  In various exemplary embodiments of the invention, the additional (third) color channel is separately transmitted by a layered waveguide designed according to any of the above embodiments. See, for example, FIGS. 21c-d, 22e-f, and 49a-b. Thus, according to a preferred embodiment of the present invention, the device 200 includes alternating layers, in which layers that transmit two color channels are inserted between layers that transmit a single color channel. The FIG. 54b shows a side view of a preferred alternating arrangement of layers. Shown in FIG. 54b are two types of layers designated by the numbers 320a and 320b. In layer 320a, two color channels are emitted from four output regions on the layer according to the embodiment shown in FIG. 54a, and in layer 320b, the third color channel is according to the embodiment shown in FIG. 49b. Emission from two output areas.

  See FIGS. 55a-c, which are schematic illustrations of a preferred embodiment in which one or more layers of device 200 include a waveguide extending from input region 293 to a plurality of output regions. In FIG. 55, the output area is designated by 294-1, 294-2, ..., 294-N. This embodiment is particularly useful when the apparatus 200 is used as a backlight assembly for either multicolor input light (eg, white light) or monochromatic input light.

  According to a preferred embodiment of the present invention, each output area can be aligned with a row or column of pixel areas of the passive display panel 64. Input light 514 propagates in waveguide 16 and is coupled out of the waveguide by redirecting element 508. The optical output can be such that different pixel areas are illuminated by substantially spaced light beams, or a uniform light output illuminates a row or column of pixel areas.

  When the input light 514 is multicolored, it can be demultiplexed to different sub-pixel locations near the pixel area, as will be described in further detail below. When the input light 514 is monochromatic, the device 200 preferably includes alternating layers, where adjacent layers transmit different color channels. A side view of the device 200 in this embodiment is shown schematically in FIG. 5c.

  As stated, element 508 can be reflective, refractive, diffractive, or any combination thereof. In the illustrated diagram of FIG. 55a, the waveguide branches into reflective elements, each reflective element coupling most of the optical output out of the layer. In the illustrated diagram of FIG. 55b, each waveguide has a plurality of portions configured such that one portion of the propagating light is redirected out of the layer and a portion of the light column continues to propagate through the element. A reflective element.

  Representative examples of suitable partially reflecting elements are shown in FIGS. 48a-d above. The amount of reflection may be the width of element 508, the difference in refractive index between element 508 and the core of the waveguide, the thickness of element 508, the reflectivity of the facet of element 508, the width of the waveguide, and / or element 508. It can be varied along each waveguide by controlling the distance between the cores of the waveguide. A configuration in which light is input from both sides of the waveguide so as to increase the uniformity of the optical output is also conceivable. Further, the cladding 266 can be shaped to control the output distribution of the optical output as described above (see, eg, FIG. 48e).

  Referring now to FIGS. 56a-b, one or more layers of the device 200 can be configured from two input regions 293a and 293b to a plurality of output regions 294a-1, 294a-2,..., 294a-N. , And 294b-1, 294b-2,..., 294b-N. A first color channel (eg, red light) enters region 293a, propagates through waveguide 16a, and is emitted from regions 294a-1, 294a-2,..., 294a-N, while a second color channel (eg, red light) (Blue light) enters the region 293b, propagates in the waveguide 16a, and is emitted from the regions 294b-1, 294b-2, ..., 294b-N. According to a preferred embodiment of the present invention, waveguide 16a is a single mode waveguide configured therein to allow propagation of a first color, and waveguide 16b is a second thereof. A single mode waveguide configured to allow color propagation.

  In various exemplary embodiments of the present invention, the additional (third) color channel is conveyed separately by layered waveguides designed according to any of the embodiments shown in FIGS. Thus, according to a preferred embodiment of the present invention, the device 200 includes alternating layers in which layers carrying two color channels are inserted between layers carrying a single color channel. FIG. 56b schematically shows a side view of a preferred alternating arrangement of layers.

  In any of the above embodiments, the outgoing light redirection is by appropriate design of the redirecting optical elements and / or using additional optical elements located in the optical path of the outgoing light beam. Can be controlled by. Where appropriate, the optical elements are preferably selected to prevent spectral crosstalk between different color channels. For example, when device 200 is used to provide backlight illumination in which monochromatic light propagates in a waveguide, the optical elements are designed and configured to direct different color channels to different subpixel positions. Is preferred. Thus, in various exemplary embodiments of the invention, the optical element focuses or collimates light present on the subpixel location. For example, the optical element can be configured such that each turning element illuminates a single sub-pixel position.

  FIG. 64 a is a schematic diagram of the backlight assembly 62 in a preferred embodiment where the backlight assembly 62 includes a microlens array 558 disposed between the redirecting element 508 and the passive display panel 64. The microlens array 558 is preferably designed and aligned to reduce spectral crosstalk between different color channels.

  The redirecting optics and / or additional optics (eg, array 558) can also be designed such that the redirecting element 508 provides illumination light to a plurality of subpixel locations associated with each color channel. This embodiment is particularly useful when the waveguides 16 are arranged in a row with respect to the passive display panel 64. Thus, the optical elements are designed and aligned to ensure that two or more rows of sub-pixel positions are provided with illumination light that is redirected by a single redirecting element. Is preferred.

  FIG. 64b schematically illustrates the backlight assembly 62 in a preferred embodiment where the microlens array 558 redirects light to impinge on multiple subpixel positions. The array and / or element 508 is designed and configured such that when the light beam passes through it, the beam conversion of the light beam is higher along the column 552 than perpendicular to the column 552 of the passive display 64. It is preferable. As recognized by those skilled in the art, such an arrangement ensures limited illumination of the subpixel positions. In other words, in a preferred embodiment of the present invention, all subpixel positions illuminated by a particular turning element are associated with the same color channel. A typical beam conversion along a column of panels is about 0.5 ° to about 20 °, and a typical beam conversion perpendicular to the column (eg, along a row of panels) is 10 degrees or less.

  Devices 200 and 30 can also be used to provide a three-dimensional image by generating two different images of two different polarizations or two different colors, as detailed above. In the case of two different polarizations, the device 200 has two optical inputs (not different colors) of two different polarizations and can be configured similarly to FIG. The user can then view the image using a binocular device having a different polarization for each eye.

  In another embodiment, devices 200 and 30 can function as autostereoscopic displays. This can be done in a number of ways, as described in detail below in connection with FIGS. 34a-d and 35a-c.

  Thus, in various exemplary embodiments of the present invention, a device 200 is manufactured having two input facets 330 and 332 that each receive a different image designed to be viewed with the user's left and right eyes. Output facet 338 directs optical information reaching input 330 to the left eye and optical information reaching input 332 to the right eye.

  Referring to FIGS. 34a-d, the layers of the apparatus 200 can be arranged such that the optical information reaching the input 330 is directed to the left eye and the optical information reaching the input 332 is directed to the right eye. . This can be done by focusing the output beam on a single spot 336, also known as the “sweet spot” of the autostereoscopic image, with the proper orientation of the mirrors 334 in different layers ( (See FIG. 34c). The user can then observe the three-dimensional image by placing the left eye on the left part 344 of the sweet spot and the right eye on the right part 342 of the sweet spot. If the device 200 is flexible, focusing of the output beam to the spot 336 can be achieved by bending the output facet 338 as shown in FIG. 34d. The advantage of the latter embodiment is that the position of the sweet spot can be changed by changing the curvature of the facet 338.

  With reference to FIGS. 35a-c, the layers of the apparatus 200 can be arranged so that the waveguide 16 has the proper orientation to focus the output beam to the spot 336. FIG. The advantage of this embodiment is that the beam orientation is dominated by the waveguide orientation, not by the mirror facet angle. Making a waveguide with a controlled orientation is much simpler than making a mirror with a controlled facet angle. In another preferred embodiment, the waveguide orientation is the same, but the mirror orientation is changed to reflect the beam in the desired direction.

  FIG. 36 schematically illustrates various optical regions within the field of view of the apparatus 200 in a preferred embodiment where the apparatus 200 provides two optical outputs, a “left” output 346 and a “right” output 348. As shown in FIG. 36, the field of view typically includes four optical regions. A mixed field region 350 where both outputs are combined to give a two-dimensional image, a sweet spot region 336 where both outputs are combined to give a three-dimensional image, and one output is blocked, thus the other output 348 or 346, respectively. These are two one-side regions 352 and 354 including only two-dimensional information. Regions 352 and 354 can be resized (reduced or enlarged) as desired by controlling the width of the output field of view.

  Referring now to FIGS. 37a-b, they show one layer (FIG. 37a) and the resulting field of view (FIG. 37b) in a preferred embodiment where the device 200 provides multiple autostereoscopic images. FIG. As shown, the end 360 of each waveguide 16 designed to emit light through the output facet is a plurality of waveguides, each terminated by a separate mirror (in this example, mirrors 364a, 364b, and 364c). (In this example, it is divided into three waveguides 362a, 362b, and 362c). The waveguides are oriented to focus each portion of light to a different sweet spot (spots 366a, 366b, and 366c in this example). As will be appreciated by those skilled in the art, this embodiment can also be used to provide a plurality of two-dimensional images in a plurality of directions. For example, when the device 200 is implemented in a display device, a user who views the display from different directions can see different images.

  As stated, when the device 30 or 200 is used in a backlight assembly, either monochromatic or polychromatic light can propagate in the waveguide.

A representative example of a preferred embodiment LCD device 60 in which monochromatic light propagates in the waveguide of the backlight assembly 62 is shown schematically in FIG. 57a. In the exemplary embodiment shown in FIG. 57 a, a small branch beam is coupled out of the assembly 62. As shown, the light travels substantially perpendicular to the passive display panel 64, thus increasing the efficiency of the LCD switching operation. It is generally degraded at large viewing angles. To facilitate the necessary output light splitting, the device 60 preferably includes a light diffuser 532 positioned in front of the passive display panel 64. Alternatively, the light branching from the backlight assembly 62 is given by the formula sin α = √ (n ₁ ² −n ₂ ² ), where n ₁ and n ₂ are the refractive indices of the core and cladding, respectively, and α is the diffraction Can be controlled by appropriate selection of the refractive index of the waveguide core and cladding.

  FIG. 57b schematically illustrates the LCD device 60 in a preferred embodiment where the LCD device 60 includes two passive display panels 64a and 64b. The use of two passive display panels is advantageous because with such a configuration, the extinction ratio of the device 60 can be significantly improved. This embodiment is particularly applicable when the optical output branch of the assembly 62 is small (eg, less than 20 °), and the resolution of the first passive display panel is maintained. In various exemplary embodiments of the present invention, apparatus 60 includes a first front polarizer 540a positioned in front of panel 64a, a second front polarizer 540b positioned in front of panel 64b, and a second front polarization. It further includes a light diffuser 532 positioned in front of the child 540b.

  A representative example of an LCD device 60 in a preferred embodiment in which monochromatic light propagates in the waveguide of the backlight assembly 62 is shown schematically in FIG. In this embodiment, the one or more waveguides demultiplex the light into two or more color channels and in a manner such that different subpixel positions are illuminated by different color channels. A demultiplexer 534 for coupling within. The demultiplexer 534 can be of any type such as, but not limited to, a grating (see FIG. 24d), a curved surface, and the like.

  FIG. 59 is a schematic diagram of the device 60 in a preferred embodiment in which the device 60 operates in a transflective mode. The transflective LCD device 60 is configured to allow observation in both a reflective mode using ambient light and a transmissive mode using backlight illumination. Unlike traditional transflective devices, where about half of the backlight illumination collides with the reflective surface and is wasted, the teachings of the present invention allow the entire backlight illumination to be transmitted to the passive display panel.

  Thus, according to a preferred embodiment of the present invention, the device 60 includes a backlight assembly 62, a panel 64, and a reflective surface 542 for reflecting ambient light to the panel 64. The apparatus 60 further includes a plurality of color filters 544 positioned in front of each subpixel position of the panel 64 to selectively transmit the respective color channels at the subpixel positions. It is noted that in the transmission mode of the device 60, the color filters are supplied by the respective color light and therefore do not reduce the light transmission.

  Apparatus 60 optionally further includes a light source 172, a back polarizer 154, and a front polarizer 540, as described in further detail above. In various exemplary embodiments of the present invention, backlight illumination is transmitted through aperture 546 in surface 542, leaving the pixel with most of the subpixel area available for reflection mode without losing intensity. Alternatively, the reflective surface 542 can be laminated or sputtered on the back side of the assembly 62. In this embodiment, no alignment between the waveguide and the opening in the surface 542 is required.

  FIG. 60 is a schematic diagram of the device 60 in a preferred embodiment in which the device 60 operates in a color sequential mode. In this embodiment, light source 172 preferably has the ability to be switched on and off at high speed to form short light pulses. Panel 64 is synchronized with source 172 such that the corresponding color field of the image is transmitted through panel 64 for any color channel. The waveguide 16 of the assembly 62 is preferably arranged such that two or more waveguides are aligned with each pixel region, and the pixel region receives illumination from all color channels.

  The coupling between the device 200 and the light source can include any of the techniques described above for the device 30, changing where to change. For this purpose, see for example Figures 16a-b, 17, 18a-b, 47a-b and the accompanying description above. When the optical input is encoded by image data, the optical coupling between the device 200 and the light source is preferably made to hold an image constituted by the input light beam. For non-coded optical inputs (eg, when the device 200 is used to provide illumination light), the waveguide can be input in a non-pixelated manner.

  Thus, the coupling between the device 200 and the light source can be performed using a coupler, for example using a microlens array with or without a polarizer, as detailed above (see FIG. 16a). Alternatively, the device 200 can function without a coupler or using a microlens array placed or formed on the input optical element, as detailed above (see FIG. 16b). In another embodiment, as detailed above and shown in FIG. 17, a lens or another focusing element can be used to focus the input image on the device 200. In additional embodiments, the coupling between the device 200 and the light source is via one or more fiber bundles (see FIGS. 18a-b) as detailed above. The apparatus 200 can also receive optical input in the form of a laser beam that can be projected onto the input facets of the apparatus 200.

  Additional techniques for coupling between the device 200 and the light source that are particularly useful (but not limited to) embodiments where there are multiple output regions (see, eg, FIGS. 55a-56b) are shown in FIGS. 61a-c and 62a-c. Is shown in

  In the preferred embodiment shown in FIGS. 61 a-c, input region 293 of layer 320 includes two or more sublayers, whereby waveguide 16 is stacked at input region 293 to provide input facets for layer 320. 560 is formed. The waveguide 16 extends from different sublayers of the input region 293 to the output region 294. 61a-c shows a plan view (FIG. 61a), a cross-sectional view (FIG. 61b) along the cutting line AA ′ passing through the output region 294, and a cutting line BB ′ passing through the input region 293. FIG. 61c is a cross-sectional view along (FIG. 61c). 61a shows three sub-layers (sub-layer 520a, sub-layer 520b, and sub-layer 520c) in input region 293, it is understood that it is not intended to limit the scope of the invention to any particular number of sub-layers Should. As shown in FIGS. 61 a-b, there is an overlap 522 in the input area 293. Waveguides 16 occupying different sublayers from region 293 preferably extend to different subregions of output region 294. In the representative example shown in FIGS. 61a-c, the output area 294 is divided into three sub-areas 524a, 524b and 524c. The waveguide extends from sublayer 520a to subregion 524a, from sublayer 520a to subregion 524b, and from sublayer 520c to subregion 524c.

  In the embodiment shown in FIGS. 62a-c, the waveguides are divided into groups and mechanically separated at the input region 293 by forming a dice-shaped region on the layer (FIG. 62a). The formed groups of waveguides are then grouped together (FIG. 62b) to form the input facets. FIG. 62c shows an embodiment that is a combination of the embodiment shown in FIGS. 47a-b and the embodiment shown in FIGS. The waveguides are mechanically separated at the input region 293 and are arranged at the input region 293 so that the termination portion of each waveguide is substantially collinear with the optical path characterizing the light source.

  As stated, any number of light sources can be coupled to the device 200. A representative example having twelve monochromatic light sources and three color channels (four light sources for each color channel) is shown schematically in FIG.

  The layer thickness of the device 200 can vary across the device 200. For example, the layer thickness may be from about 15 μm to about 30 μm at the input facet and from about 40 μm to about 60 μm at the output facet. At the output facet, the overlap between the layers is limited to only a few layers, so the total thickness of the device 200 is not affected by the thick layers in the output region. The advantage of a thick waveguide layer is that such a configuration increases the transmission area from the redirecting optical element. The layer thickness can be increased continuously or stepwise as desired. For example, a stepped increase in thickness can occur at the interface where the waveguide is exposed.

  In any of the above embodiments, the waveguide is preferably designed and configured to provide a uniform optical output. This embodiment is particularly useful when the optical device of this embodiment is used as a backlight assembly. Thus, according to a preferred embodiment of the present invention, input non-uniformity is corrected at the waveguide level by introducing changes in the dimensions of the waveguide. See, for example, the layout shown in FIG. 39 in the Examples section below. Alternatively, a uniform light source can be used.

  However, non-uniform optical output can also be the result of different transmission efficiencies of different waveguides due to light loss in the waveguide. Typically, optical loss increases with waveguide length. Such non-uniform optical output can be corrected by adding losses to the short waveguide and / or selecting a wide cross section for the input side of the long waveguide, as shown in FIG. 39b. Such a configuration couples a lot of light into a wide range of waveguides to overcome their high losses.

  Different layers of the optical device of this embodiment can have waveguides of different lengths (see, eg, FIGS. 22a-c). Equal transmission efficiency for waveguides in different layers is achieved by selecting different widths for waveguides in different layers, according to various exemplary embodiments of the invention. More preferably, the thickness of the core in the layer can be varied to achieve a uniform optical output. In particular, in a layer with a short waveguide, the core is thicker than a core with a long waveguide. The use of different core thicknesses for different layers is preferred from a manufacturing simplicity standpoint. This is because such a technique allows the same mask to be used to produce many layers.

  During the lifetime of this patent, many related light transmissive devices are expected to be developed, and the term “waveguide” is intended to include all such new technologies a priori. Yes.

  Further objects, advantages and novel features of the present invention will become apparent to those skilled in the art upon review of the following examples, which are not intended to be limiting. In addition, each of the various embodiments and aspects of the invention as described hereinabove and as claimed in the claims section below, is experimentally supported by the following examples. Found in

  Reference is now made to the following examples, which together with the above description, illustrate the invention in a non limiting fashion.

Example 1
Optimizing Optical Loss The transparency of the device can include several loss mechanisms: (i) propagation loss within the device, (ii) bending and tapering loss within the device, (iii) coupling loss between the optical elements of the device, and (Iv) affected by reflection loss at the interface.

  The lowest propagation loss reported for polymer waveguides was achieved with polymethylmethacrylate (PMMA) and deuterated polyfluoromethacrylate (d-PFMA) materials that do not contain CH absorption vibrational coupling. Values less than 0.001 dB / cm in the visible region in the case of bulk [L. Hornak, “Polymers for lightwave and integrated optics”, Marcel Dekker, Inc, 1992]; 0.01 dB / cm at the wavelength of λ = 0.68 μm for multimode waveguides [Yoshimura et al. with Deuterated Polyfluoromethlylate, "J. Lightwave Tech, vol 16, 1030-1037, 1998], and 0.05 dB / cm at λ = 1.3 μm for single mode waveguides [Yeniary et al., “Ultra-low-loss polymer waves”, J. MoI. Lightwave Tech, vol 22, 154-158, 2004] has been reported. Therefore, in a preferred embodiment of the present invention, the waveguide is a polymer waveguide, more preferably a PMMA waveguide or a d-PFMA waveguide.

  The bending loss in the various exemplary embodiments of the present invention is due to the interaction of the light with the corner mirror. A corner loss of 1.2 dB has been reported for a 50 × 50 μm multimode polymer waveguide with an air-clad mirror. [J-S Kim and J-J Kim, “Stacked polymeric multi-waveform arrays for two-dimensional optical interconnects”, J. Kim et al. Lightwave Tech, vol 22, 840-844, 2004]. Lower losses of less than 0.5 dB are also achievable [Ahmad, “Ultracompact corner-mirrors and T-branches in silicon-on-insulator”, IEEE Photon. Tech. Lett. , Vol. 14, 65-67, 2002]. If a waveguide with a radius of curvature of several millimeters is used instead of a corner mirror, the loss can be lower than 0.1 dB.

  When the device is used for light expansion (eg, image magnification), the tapering loss is negligibly small. In the case of contraction, typical tapering loss depends on the mode structure and taper length of the input beam. In the basic input mode, for a taper of a few millimeters in length, the loss can be less than 0.1 dB. Thus, when the device is used for light expansion, the tapering can be stepped, and when used for shrinkage, a smooth tapering is preferred to minimize losses.

  The degree of coupling loss at the interface between the input light source and the device depends on the optical arrangement used to facilitate coupling, the waveguide core to cladding ratio, and the pixel width to gap ratio (etching). As long as there is no focusing element at the facet). When the waveguide has a rectangular cross section, the filling factor is higher than that in the case of a waveguide having a circular cross section. The degree of coupling loss between the optical elements of the device can be negligibly low by judicious choice of the numerical aperture of the waveguide. In particular, in a preferred embodiment of the present invention, the numerical aperture of the receiving optical element (eg element 34) is higher than or equal to the numerical aperture of the radiating optical element (eg element 32).

The reflection between the input light source and the device 30 can be negligibly low by placing a refractive index matching adhesive between the device 30 and the optical array that couples the light source to the device 30. The same is true for reflections between the optical elements of the device. The reflection at the large facet of the second optical element is given by (n−1) ² / (n + 1) ² . Here, n is the refractive index of the core. This facet can be coated with an anti-reflective coating to further reduce reflection.

  Since lossy scattered light propagates substantially parallel to the large facets of device 30, the contrast ratio of the device is only slightly affected by propagation loss. Nevertheless, light loss at the interface-to-interface bond and light scattered by bending can reduce the contrast ratio, especially in embodiments where the layer regions 18 and 20 are parallel and located on both sides of the layer. is there.

  Light loss due to non-uniform propagation loss of the waveguide is reduced or substantially eliminated by illuminating the input image non-uniformly (eg, less than 20% of its original value, more preferably less than 10%, For example, it can be reduced to about 5% or less. For example, with reference to FIG. 38, the input image 380 can be distorted such that there is a brightness gradient 382 over the length and width of the image to compensate for differential waveguide losses.

  FIG. 39a is a schematic diagram of a layer of an optical element (eg, layer 14) in a preferred embodiment that includes a light absorber 370 that is selected to improve the contrast ratio of light propagating in the waveguide 16. is there. The light absorber 370 can be deposited on the entire layer 14 or in a small area within the layer 14. The light absorber may be a black tone added to the cladding material. In embodiments where regions 18 and 20 are collinear or on the adjacent side of layer 14, the effect of reducing the contrast ratio is less pronounced and the skilled person prefers to include a light absorber 370. It may not be. Nevertheless, the use of a light absorber is also envisaged in these embodiments. An alternative way to improve the contrast ratio is to use a slightly absorbing cladding layer between the waveguides. For example, a cladding layer with an absorption coefficient of about 1 dB / cm can absorb all or most of the scattered light while keeping the addition of waveguide losses below 0.01 dB / cm.

  If the propagation loss is not uniform, the output light beam can have non-uniform brightness. In order to avoid that effect, parasitic losses can be added to the short waveguide. This can be done in several ways. In one embodiment, parasitic losses can be added by reducing the width of the waveguide. In another embodiment, parasitic losses are added by reducing the bend radius. In additional embodiments, parasitic losses are generated by adding bending or parasitic crossing waveguides to the layers.

  Alternatively, the coupling to the waveguide is adjusted by changing the taper width (which controls the amount of light coupled to the waveguide) or the taper length (which controls the efficiency of the taper [transparency]). Can.

  If it is necessary to resize a homogeneous panel, different losses in the waveguide can be compensated by assigning different cross sections to the waveguide. FIG. 39b shows that the longer waveguide of the layer is wider so that more light is coupled into the wider waveguide to overcome their higher losses (due to their longer length). 1 schematically shows an embodiment having a cross section of In this embodiment, the waveguide is tapered towards the output panel to obtain a uniform width there. Non-tapered waveguides are also conceivable. It is also possible to replace the 90 ° waveguide bend with a smooth bend.

  Waveguides can have different lengths not only within a layer but also between layers. The waveguide in the upper layer is shorter than the waveguide in the lower layer. Equal transparency of waveguides in different layers can be achieved by assigning different waveguide widths for each layer. Alternatively, the thickness of the (core) waveguide in the layer can be varied to compensate for the length of the different waveguides in the layer. In this embodiment, the waveguide in the upper layer is narrower than the waveguide in the lower layer.

Example 2
Field Optimization In a preferred embodiment of the present invention, the device 30 is designed and configured to provide resized light to a predetermined field of view. One way to achieve a predetermined field of view for the device 30 is by judicious selection of the waveguide parameters of the optical element (eg, element 34) from which the device 30 outputs light. In a preferred embodiment of the present invention, the refractive index and numerical aperture (NA) of the waveguide are given by the equation: N.A. A. = Sin α = √ (n ₁ ² −n ₂ ² ). Here, n ₁ and n ₂ are the refractive indexes of the core and the cladding, respectively, and α is a half of the diffraction angle. In the case of a waveguide terminated with a linear taper, the effective numerical aperture is N.D. A. / M. Where M is the taper ratio [Peli et al., Supra]. Thus, the effective field of view can be selected by adjusting the taper shape, ie, using a non-linear taper shape. In particular, different fields of view can be obtained for different directions.

  The different fields in different directions select the first cladding material in the layer so that the longitudinal field (parallel to the layer) is different from the lateral field (substantially perpendicular to the layer) and between the layers It can also be achieved by selecting a second different cladding material.

  The field of view of the device 30 can be expanded by adding a diffusing screen to the output facet or by etching the output facet to make it diffusive. The diffusing screen can also be configured to compensate for light loss.

  In addition or alternatively, the field of view can be expanded by increasing the difference in refractive index Δn between the core and the cladding. High Δn values can be selected for the entire optical element, or alternatively, Δn can be progressively increased toward the output facet. A gradual change in Δn can be achieved, for example, in a production process in which the core is written by direct write UV lithography where the Δn of the core relative to the cladding is a function of the UV exposure time. The increase in refractive index preferably occurs simultaneously with diffusion mechanisms such as additional scattering centers in the core material or scattering due to the addition of bending to the waveguide. These scattering mechanisms take advantage of the ability of higher Δn waveguides to retain higher order modes to convert lower order modes to higher order modes. Higher order modes contribute to a large field pattern.

  As will be appreciated by those of ordinary skill in the art, the ability to adjust the field of view can significantly improve the brightness of the output light.

  Reference is now made to FIG. 40, which shows a procedure for improving the brightness of the output light. In general, improvements include efficiently collecting light 390 from the light source 392 and adjusting the field of view of the device 30 so that the loss of brightness is minimal or zero. In particular, in a preferred embodiment of the present invention, the field of view is reduced by the same amount as the expected reduction in brightness because all or most (eg, at least 90%) of the optical energy of light 390 is carried by output light 394. Is done. For example, assume that a 5 ″ screen is magnified to 10 ″ using an optical device having an insertion loss of 3 dB. In this case, the expected decrease in brightness of the device 30 is 2 × 2 × 2 = 8. Further assume that device 30 is coupled to light source 392 such that 120 ° light 390 is incident on device 30. In order to eliminate the decrease in brightness, the field of view of the device 30 is selected to be 120√8 = 42 °. This embodiment is particularly useful in situations where it is desirable to increase screen size with reduced field of view, for example for the purpose of maintaining the privacy of the displayed image.

  Reference is now made to FIG. 41, which is a schematic illustration of the device 30 in a preferred embodiment, in which the waveguide 16 is inclined with respect to the end of the layer (see, eg, FIG. 19). The resulting optical element emits light 394 at an angle θ relative to the output facet. As shown in FIG. 41, this embodiment results in a change in the field of view of the device 30.

  The field of view adjustment can also be used at the interface between the optical elements of the device 30 to increase the spatial mode of the light receiving element. Tuning can be achieved by changing the relative orientation between the waveguides of different optical elements and / or the value of Δn. For example, when the waveguide of the transmissive element (eg, element 32) is not parallel to the waveguide of the light receiving element (eg, element 34) and Δn of the light receiving element is higher than Δn of the transmissive element, excitation occurs at the interface between the two elements. The high spatial mode successfully propagates through the light receiving element. As a result, the field of view of the output facet of the device is increased. By establishing a tilted connection between the two waveguides of the optical element, spatial mode increments can also be achieved within the optical element (not on the interface between two such elements).

  As used herein, the term “about” refers to ± 10%.

  It will be appreciated that certain features of the invention described in the context of separate embodiments for clarity may also be provided in combination in a single embodiment. Conversely, various features of the invention described in the context of a single embodiment for the sake of brevity can also be provided separately or in appropriate subcombinations.

  While the invention has been described in terms of specific embodiments thereof, it will be apparent to those skilled in the art that there are many alternatives, modifications, and variations. Accordingly, the present invention is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims. All publications, patents, and patent applications cited in this application are hereby incorporated by reference in their entirety as if each individual publication, patent, and patent application were specifically and individually cited. To do. Furthermore, citation or confirmation in this application should not be considered as a confession that it can be used as prior art to the present invention.

1 is a prior art schematic diagram for manufacturing a fiber-based guidance magnifier. FIG. 1 is a prior art schematic diagram for manufacturing a fiber-based guidance magnifier. FIG. FIGS. 3a-c illustrate longitudinally expanding arrays of waveguides (FIG. 3a), partially tapered waveguides (FIG. 3b), and partially tapered waveguides, according to various exemplary embodiments of the present invention. Fig. 3c is a schematic view of a longitudinally extending array (Fig. 3c). FIG. 3d is a schematic diagram of the embodiment of FIG. 3c with two or more layers. 2 is a schematic diagram of an optical resizing element in various exemplary embodiments of the invention. FIG. 2 is a schematic diagram of an optical resizing element in various exemplary embodiments of the invention. FIG. 1 is a schematic diagram of an optical resizing device having two optical resizing elements in various exemplary embodiments of the present invention. FIG. FIG. 6a is a schematic diagram of small facets of a receiving optical resizing element in various exemplary embodiments of the present invention. FIG. 6b is a three-dimensional view of the waveguide of the device of FIG. 6a in various exemplary embodiments of the invention. 3 is a three-dimensional schematic diagram of an apparatus of an embodiment in which the incident and exit facets of each optical resizing element are substantially orthogonal to each other. FIG. FIG. 7b is a three-dimensional schematic diagram of the apparatus of FIG. 7a in a preferred embodiment employing two pairs of optical resizing elements. FIG. 2 is a schematic diagram of an apparatus in a preferred embodiment in which the facets of one optical resizing element are substantially parallel and the facets of the other optical resizing element are substantially orthogonal. FIG. 2 is a schematic view of an apparatus in a preferred embodiment where the facets of the optical resizing element are substantially coplanar. FIG. 6 is a schematic diagram of a photomask layout for manufacturing an array of waveguides in accordance with various exemplary embodiments of the invention. FIG. 6 is a schematic diagram of a process for manufacturing a waveguide that is tapered in both the vertical and lateral directions. 1 is a schematic diagram of an optical resizing device in a preferred embodiment using multiple light sources. FIG. 1 is a schematic diagram of an optical resizing device in a preferred embodiment using multiple light sources. FIG. FIG. 2 is a schematic diagram of an apparatus in a preferred embodiment where there are two or more optical outputs from the apparatus. FIG. 3 is a schematic diagram of an apparatus in a preferred embodiment where the apparatus includes one or more additional optical elements. FIG. 3 is a schematic diagram of layers of an optical resizing element in a preferred embodiment in which the layer includes a polarizer. FIG. 2 is a schematic diagram of the coupling between the device and the light source in a preferred embodiment where the light source is an image source. FIG. 2 is a schematic diagram of a preferred embodiment in which an input image is focused on the device using a lens. FIG. 6 is a schematic diagram of the coupling between the device and the light source in a preferred embodiment in which one or more fiber bundles are used. 1 is a schematic diagram of one layer of an optical resizing element in a preferred embodiment in which the waveguide is tilted with respect to the edge of the layer. FIG. 1 is a schematic diagram of an optical resizing device in a preferred embodiment in which the device is manufactured according to the principle of partially overlapping optical arrangements. 1 is a schematic diagram of an optical resizing device in a preferred embodiment in which the device is manufactured according to the principle of partially overlapping optical arrangements. 1 is a schematic diagram of an optical resizing device in a preferred embodiment in which the device is manufactured according to the principle of partially overlapping optical arrangements. 1 is a schematic diagram of an optical resizing device in a preferred embodiment in which the device is manufactured according to the principle of partially overlapping optical arrangements. FIGS. 23a-b are a schematic side view (FIG. 23a) and a schematic top view (FIG. 23b) of a portion of a facet of a device similar to that of FIGS. 20-22 in a preferred embodiment where the facet has a two-dimensional stepped shape. ). 23c-d are schematic illustrations of mirror shapes according to various exemplary embodiments of the present invention. FIG. 2 is a schematic side view of an optical resizing element with a two-dimensional stepped or tilted profile according to various exemplary embodiments of the present invention. FIG. 2 is a schematic side view of an optical resizing element with a two-dimensional stepped or tilted profile according to various exemplary embodiments of the present invention. FIG. 2 is a schematic side view of an optical resizing element with a two-dimensional stepped or tilted profile according to various exemplary embodiments of the present invention. 1 is a schematic view of a bendable optical resizing device according to a preferred embodiment of the present invention. FIG. 6 is a schematic diagram of a configuration in which light is coupled out of a device through an array of transmissive elements, according to various exemplary embodiments of the present invention. FIG. 4 is a schematic diagram of a process for manufacturing a tilted optical resizing element in various exemplary embodiments of the invention. FIG. 3 is a schematic diagram of an expansion structure according to various exemplary embodiments of the present invention. FIG. 3 is a schematic diagram of an expansion structure according to various exemplary embodiments of the present invention. FIG. 3 is a schematic diagram of an expansion structure according to various exemplary embodiments of the present invention. FIG. 23 is a schematic top view (FIGS. 28a-b) and a schematic side view (FIG. 28c) of a layer of a device similar to that of FIGS. 20-22 in a preferred embodiment where the layer is a lightweight layer. FIG. 23 is a schematic diagram of a suitable folding technique for manufacturing a device similar to that of FIGS. 20-22, in accordance with various exemplary embodiments of the present invention. FIG. 6 is a schematic diagram of a simultaneous process for manufacturing a plurality of optical resizing elements in various exemplary embodiments of the invention. FIG. 23 is a schematic diagram of an apparatus similar to that of FIGS. 20-22 in a preferred embodiment in which the apparatus receives light from multiple light sources. Figure 23 is a schematic top view (Figure 32a) and schematic cross-sectional view (Figure 32b) of an apparatus similar to the apparatus of Figures 20-22 in a preferred embodiment where the apparatus receives optical input in the form of a plurality of monochromatic light sources. FIG. 23 is a schematic diagram of a technique for coupling light out of a device layer similar to that of FIGS. 20-22, according to various exemplary embodiments of the present invention. FIG. 23 is a schematic diagram of an apparatus similar to that of FIGS. 20-22 in a preferred embodiment in which the apparatus is used to provide autostereoscopic images. FIG. 23 is a schematic diagram of an apparatus similar to that of FIGS. 20-22 in a preferred embodiment in which the apparatus is used to provide autostereoscopic images. FIG. 36 is a schematic illustration of different optical regions in the field of view of a device similar to that of FIGS. 34a-35c. FIG. 38 is a schematic diagram of a single layer (FIG. 37a) and the resulting visual field (FIG. 37b) in a preferred embodiment where multiple autostereoscopic images are provided. 1 is a schematic diagram of an optical resizing device in a preferred embodiment where the input image has non-uniform brightness to compensate for differential waveguide losses. FIG. FIG. 39a is a schematic diagram of layers of an optical resizing element in a preferred embodiment where the layers include a light absorber. FIG. 39b is a schematic diagram of a waveguide with variable cross section according to a preferred embodiment of the present invention. FIG. 6 is a schematic diagram of a procedure for improving the brightness of output light in various exemplary embodiments of the present invention. FIG. 6 is a schematic diagram of a procedure for modifying the field of view of an apparatus in various exemplary embodiments of the invention. FIG. 42a is a schematic diagram of a conventional edge-lit LCD device. FIG. 42b is a schematic diagram of a backlight technology designed to overcome the inherent 2/3 output loss. 1 is a schematic diagram of a backlight technology designed to overcome inherent 2/3 power loss. FIG. 1 is a schematic view of a display device using one or more optical elements of the present embodiment. Fig. 44 is a schematic view of a passive display panel (Fig. 44a) and its pixel area (Fig. 44b). It is the schematic of a passive display panel. FIG. 2 is a schematic diagram of a backlight assembly according to various exemplary embodiments of the invention. FIG. 6 is a schematic diagram of a color distribution of backlight illumination provided by a backlight assembly to a passive display panel, according to various exemplary embodiments of the present invention. A preferred technique for coupling light into a backlight assembly, wherein the waveguides are disposed in each layer such that the termination portion of each waveguide is substantially collinear with at least one optical path characterizing the light source. FIG. FIG. 3 is a schematic diagram of a technique for redirecting light out of a waveguide, according to various exemplary embodiments of the present invention. FIG. 3 is a schematic diagram of a technique for redirecting light out of a waveguide, according to various exemplary embodiments of the present invention. FIG. 49 is a schematic diagram of a preferred layer design for a configuration in which layer waveguides illuminate one (FIG. 49a) and two (FIG. 49b) subpixels per row. A schematic side view of a stack of layers of the type shown in FIG. 49b is shown. FIG. 3 is a schematic diagram of a single layer including a first waveguide that branches into a plurality of second waveguides extending to an input region, in accordance with various exemplary embodiments of the present invention. FIG. 6 is a schematic diagram of a preferred embodiment for guiding a plurality of color channels in a single layer, with a plurality of first waveguides extending from one input region to a plurality of output regions. A single layer where the layer includes a waveguide extending from multiple input regions to multiple output regions, each color channel entering the layer at one input region, propagating through the waveguide, and exiting the layer at one output region FIG. 2 is a schematic view of a preferred embodiment for guiding a plurality of color channels. FIG. 54a is a schematic diagram of a single layer according to another preferred embodiment for guiding multiple color channels in a single layer. FIG. 54b is a schematic diagram of a side view of an optical device having an alternating arrangement of the layers of FIG. 49a and the layers of FIG. 54a, according to various exemplary embodiments of the present invention. FIG. 6 is a schematic diagram of waveguide layers in a preferred embodiment in which the waveguide extends from an input region to a plurality of output regions. FIG. 2 is a schematic diagram of a preferred embodiment in which a few layers include two input regions and multiple output regions. 1 is a schematic diagram of a preferred embodiment LCD device including a front light diffuser. FIG. 1 is a schematic diagram of a preferred embodiment LCD device including two passive displays. FIG. 1 is a schematic diagram of a preferred embodiment LCD device in which monochromatic light propagates into a waveguide of a backlight assembly. FIG. 1 is a schematic diagram of a preferred embodiment LCD device operating in a transmissive mode. FIG. 1 is a schematic diagram of a preferred embodiment LCD device operating in a continuous color mode. FIG. FIG. 56 is a schematic illustration of additional optical coupling techniques (not particularly limited) useful in embodiments with multiple output regions (see, eg, FIGS. 55a-56b). FIG. 56 is a schematic illustration of additional optical coupling techniques (not particularly limited) useful in embodiments with multiple output regions (see, eg, FIGS. 55a-56b). FIG. 3 is a schematic diagram of a backlight assembly that receives optical input from 12 monochromatic light sources. 1 is a schematic diagram of a preferred embodiment backlight assembly including a microlens array; FIG.

Claims (86)

  A backlight assembly for providing illumination light to a passive display panel having a plurality of pixel areas each defined by at least two subpixel positions each corresponding to at least two color channels characterizing the pixel area, The light assembly includes a plurality of waveguides that are formed and / or embedded in at least one substrate and that illuminate light at each subpixel location in a manner such that each pixel region is illuminated by at least two waveguides. A backlight assembly, wherein each waveguide of the at least two waveguides is arranged to illuminate one sub-pixel location of the pixel region by a respective color channel. A passive display panel having a plurality of pixel regions, each defined by at least two subpixel locations, each corresponding to at least two color channels characterizing the pixel region;
Including a plurality of waveguides, which are formed and / or embedded in at least one substrate and provide illumination light to each sub-pixel location in such a way that each pixel region is illuminated by at least two waveguides A backlight assembly, wherein each of the at least two waveguides is arranged to illuminate one sub-pixel location of the pixel region by a respective color channel;
Including a passive display device.   At least one of the plurality of waveguides is arranged in a backlight assembly layer in a row with respect to the passive display panel from at least one input region of the layer to at least one output region of the layer. The backlight assembly or passive display device according to claim 1, wherein the backlight assembly is disposed on the backlight assembly.   Formed in the at least one waveguide and configured to redirect the light out of the at least one waveguide, thereby illuminating a plurality of sub-pixel locations along each column of the passive display panel The backlight assembly or passive display device according to claim 3, further comprising a plurality of redirecting elements.   5. A backlight assembly or passive display device according to claim 4, wherein each redirecting element is arranged in the at least one waveguide so as to illuminate one sub-pixel position along the column.   5. A backlight assembly or passive display device according to claim 4, wherein at least one redirecting element is arranged in the at least one waveguide so as to illuminate at least two sub-pixel positions along the column.   The at least one redirecting element is designed to redirect the light beam propagating to the at least one waveguide such that the beam turning of the light beam is higher along the column than perpendicular to the column. The backlight assembly or passive display device according to claim 6, wherein the backlight assembly is passively configured.   The backlight assembly or claim 8, wherein the at least one redirecting element is designed and configured such that the light beam impinges on the at least two sub-pixel locations along the column. Passive display device.   The backlight assembly or passive display device according to claim 1 or 2, wherein at least one of the plurality of waveguides is tapered.   The plurality of waveguides are arranged in layers in a plurality of layers, each layer designed to allow the emission of light propagating in the layer waveguides to subpixel locations corresponding to a single color channel. The backlight assembly or passive display device according to claim 1 or 2, wherein the backlight assembly is a passive display device.   The plurality of waveguides are arranged in layers in a plurality of layers, each layer designed to allow emission of light propagating in the layer waveguides to subpixel locations corresponding to at least two color channels. The backlight assembly or passive display device according to claim 1 or 2, wherein the backlight assembly is a passive display device.   The passive display device of claim 2, further comprising a light diffuser positioned in front of the passive display panel.   And further comprising at least one additional passive display panel positioned in front of the passive display panel, wherein the at least one additional passive display panel is designed and configured to increase an extinction ratio of the passive display device. The passive display device according to claim 2.   A backlight assembly for providing illumination light to a passive display panel having a plurality of pixel regions each defined by at least two sub-pixel locations each corresponding to at least two color channels characterizing the pixel region, the backlight assembly comprising: A light assembly is formed and / or embedded in at least one substrate, and at least one of the plurality of waveguides demultiplexes light propagating in the waveguide into at least two color channels. And an optical demultiplexer designed and configured to couple the light into each pixel region such that different sub-pixel locations of the pixel region are illuminated by different color channels of the at least two color channels. Including backlight assembly . A passive display panel having a plurality of pixel regions each defined by at least two sub-pixel locations respectively corresponding to at least two color channels constituting the pixel region;
A backlight assembly comprising a plurality of waveguides formed and / or embedded in at least one substrate, each waveguide decoupling light propagating into the waveguides into at least two color channels. An optical demultiplexer designed and configured to multiplex and couple the light into respective pixel regions such that different sub-pixel locations of the pixel region are illuminated by different color channels of the at least two color channels Including a backlight assembly,
A passive display device including:   16. The backlight assembly or passive of claim 1, 2, 14, or 15, wherein the backlight assembly includes a plurality of light sources arranged such that at least one waveguide is provided by at least one light source. Display device.   16. The backlight assembly or passive of claim 1, 2, 14, or 15, wherein the backlight assembly includes a plurality of light sources arranged such that at least one waveguide is provided by at least two light sources. Display device.   The backlight assembly or passive display device of claim 16 or 17, wherein at least a few of the plurality of light sources are configured to provide polarized light.   The backlight of claim 16 or 17, wherein the backlight assembly further comprises a polarizer positioned between the plurality of light sources and the plurality of waveguides to polarize light exiting the plurality of light sources. Light assembly or passive display device.   The backlight assembly or passive display device according to claim 16 or 17, wherein at least one of the plurality of light sources includes a monochromatic light source.   The plurality of waveguides may include the at least one waveguide such that in each layer the waveguide extends from at least one input region of the layer to at least one output region of the layer, thereby defining a peripheral boundary within the layer. 16. A backlight assembly according to claim 1, 2, 14 or 15, arranged in layers on a substrate, wherein the length characterizing the peripheral boundary is smaller in the at least one input region than in the at least one output region. Passive display device.   The back of claim 21, wherein the at least one substrate includes at least one input substrate and an output substrate, and each layer in the at least one input substrate is optically coupled to a layer of the output substrate. Light assembly or passive display device.   The separation distance between layers in the output substrate is compatible with the separation distance between sub-pixels along the row of the passive display panel, and the separation distance between waveguides of the output substrate in the at least one output region is the passive display panel. 23. A backlight assembly or passive display device according to claim 22, which can be adapted to the separation distance between the sub-pixels along the rows.   23. The backlight assembly of claim 22, wherein at least one layer of the output substrate is designed and configured to emit light received from a respective layer of the at least one input substrate in a plurality of directions. Or a passive display device.   23. The backlight assembly or passive display device of claim 22, wherein at least one layer of the at least one input substrate is designed and configured to emit light in at least two different directions.   The plurality of waveguides are arranged in layers in an optical arrangement that partially overlaps within the at least one substrate, each layer comprising a waveguide extending from at least one input region of the layer to at least one output region of the layer. 16. A backlight according to claim 1, 2, 14 or 15 comprising, whereby the at least one output region is optically exposed to allow emission of light propagating in the waveguide of the layer. Assembly or passive display device.   The at least one input region includes a plurality of sublayers, and at least a few waveguides are stacked to extend from different sublayers of the at least one input region to form an input facet of the layer. , 2, 14 or 15 of the backlight assembly or passive display device.   At least one waveguide of the plurality of waveguides is tapered such that a diameter that characterizes the waveguide is larger in a direction closer to the at least one input region than in a direction away from the at least one input region; 27. A backlight assembly or passive display device according to claim 21 or 26.   27. A backlight assembly or passive display device according to claim 4, 21 or 26, wherein the backlight assembly comprises a plurality of light sources arranged such that at least one waveguide is supplied by at least one light source. .   The waveguide is such that, for each waveguide, a termination portion of the at least one input region is substantially collinear with at least one optical path characterizing at least one light source of the plurality of light sources. 30. A backlight assembly or passive display device according to claim 29, arranged in the layer of at least one input region.   The backlight assembly further includes a plurality of redirecting elements formed in the waveguide of the at least one output region of the layer and configured to redirect the light out of the waveguide. 27. A backlight assembly or passive display device according to claim 26.   32. The backlight assembly or passive display device according to claim 31, wherein the redirecting element is arranged such that at least two rows of subpixel positions of the passive display panel are illuminated by waveguides in each layer.   At least a few of the plurality of waveguides include a core and a cladding, the core has a higher refractive index than the cladding, and the cladding is shaped such that light is focused by the cladding following the turning. 32. A backlight assembly or passive display device according to claim 4 or 31.   A microlens array disposed between the plurality of redirecting elements and the passive display panel, wherein the microlens array is designed and aligned to reduce spectral crosstalk between different color channels; 32. A backlight assembly or passive display device according to claim 4 or 31.   35. The backlight assembly of claim 34, wherein the microlens array is designed and aligned to ensure that each subpixel position is provided with illumination light that is redirected by one redirecting element. Or a passive display device.   The microlens array is designed and aligned to ensure that at least two columns of sub-pixel positions are provided with illumination light that is redirected by one redirecting element. 34. A backlight assembly or passive display device according to 34.   At least one microlens of the microlens array has a beam redirection of the light beam that is less along the column than perpendicular to the column of the passive display when the light beam passes through it. 35. The backlight assembly or passive display device of claim 34, wherein the backlight assembly is designed and configured as such.   32. The backlight assembly or passive display device according to claim 4 or 31, wherein at least one of the plurality of redirecting elements is a mirror.   39. The backlight assembly or passive display device of claim 38, wherein the mirror is a total internal reflection mirror.   40. The backlight assembly or passive display device of claim 38, wherein the mirror is an etched mirror.   40. The backlight assembly or passive display device of claim 38, wherein the mirror is coated with a highly reflective coating.   40. The backlight assembly or passive display device of claim 38, wherein the mirror includes a planar facet.   40. The backlight assembly or passive display device of claim 38, wherein the mirror comprises a non-planar facet.   32. The backlight assembly or the passive display device according to claim 4 or 31, wherein at least one of the plurality of redirecting elements has a wedge structure.   45. The backlight assembly or passive display device according to claim 44, wherein the wedge structure is a diffractive wedge structure.   32. The backlight assembly or passive display device according to claim 4 or 31, wherein at least one of the plurality of redirecting elements is a Bragg reflector.   32. The backlight assembly or passive display device according to claim 4 or 31, wherein at least one of the plurality of redirecting elements is a holographic optical element.   32. The method of claim 4 or 31, wherein at least a few of the plurality of redirecting elements are designed and configured such that at least one waveguide of at least one layer emits light from at least two spaced locations. A backlight assembly or passive display device as described.   49. The backlight assembly or passive display device of claim 48, wherein a separation distance between the at least two spaced locations is substantially equal to a row separation distance characterizing the passive display panel.   At least one of the plurality of redirecting elements is configured such that a first portion of light propagating in the at least one waveguide is redirected out of the at least one layer, and a second portion of the light is 49. A partially reflective element positioned in the at least one waveguide of the at least one layer to propagate through the partially reflective element to the at least one waveguide. Backlight assembly or passive display device.   51. The backlight assembly or passive display device of claim 50, wherein the at least one substrate includes at least one reflective layer.   52. The backlight assembly or passive display device of claim 51, wherein the at least one reflective layer is characterized by a reflectance gradient along the waveguide.   16. A backlight assembly according to claim 1, 2, 14 or 15, wherein each waveguide is designed and configured such that the illumination area of the waveguide is approximately equal to the area of the subpixel location illuminated thereby. Or a passive display device.   16. A backlight according to claim 1, 2, 14 or 15, wherein each waveguide is designed and configured such that the illumination area of the waveguide is substantially smaller than the area of the subpixel location illuminated thereby. Assembly or passive display device.   55. The backlight assembly or passive display device of claim 54, wherein the plurality of waveguides are arranged such that each sub-pixel location of each pixel region is illuminated by the plurality of waveguides.   27. The backlight assembly of claim 26, wherein each layer is designed and configured to allow emission of light propagating in the layer's waveguide to subpixel locations corresponding to a single color channel. Body or passive display device.   27. The backlight assembly of claim 26, wherein each layer is designed and configured to allow emission of light propagating in the layer's waveguide to subpixel locations corresponding to at least two color channels. Body or passive display device.   At least a few layers of the partially overlapping optical arrangement are waveguides extending from a first input region of the layer to a first output region of the layer, wherein the first output region corresponds to a first color channel A waveguide that is optically exposed to allow light emission to a sub-pixel location; and a waveguide that extends from a second input region of the layer to a second output region of the layer, wherein the second output region is 27. The backlight assembly or passive display device of claim 26, wherein the backlight assembly is optically exposed to allow emission of light to subpixel locations corresponding to two color channels.   At least one layer of the partially overlapping optical arrangement includes a waveguide extending from an input region of the at least one layer to an output region of the at least one layer, the output region corresponding to a third color channel 59. The backlight assembly or passive display device according to claim 58, wherein the backlight assembly or passive display device is optically exposed to allow emission of light to subpixel locations.   60. The backlight assembly or passive display of claim 26, 58 or 59, wherein the partially overlapping optical arrangement is characterized by an exposed length that can be adapted to a separation distance that characterizes the passive display panel. apparatus.   61. The backlight assembly or passive display device of claim 60, wherein the exposed length is selected to establish optical communication between at least two columns of the passive display panel and the at least one output region. .   60. A backlight assembly or passive display device according to claim 26, 58 or 59, wherein the separation distance between the waveguides along the at least one output region can be adapted to the separation distance between the rows characterizing the passive display panel. .   16. The backlight assembly or passive display device according to claim 1, 2, 14 or 15, wherein an input side of the plurality of waveguides is wider with respect to a longer waveguide with respect to a shorter waveguide.   16. The backlight assembly or passive display device of claim 1, 2, 14 or 15, further comprising a reflective layer positioned to reflect ambient light to illuminate the passive display panel with the ambient light.   The backlight assembly or passive display device of claim 64, wherein the reflective layer is located between the plurality of waveguides and the passive display panel.   The backlight assembly or passive display device of claim 64, wherein the plurality of waveguides are located between the reflective layer and the passive display panel.   27. A backlight assembly or passive display device according to claim 21 or 26, wherein the at least one input area and the at least one output area are provided on opposite sides of the layer.   68. The backlight assembly or passive display device of claim 67, wherein the at least one input area and the at least one output area are parallel.   68. The backlight assembly or passive display device of claim 67, wherein the at least one input region and the at least one output region are provided on adjacent sides of the layer.   70. The backlight assembly or passive display device of claim 69, wherein the at least one input area and the at least one output area are substantially orthogonal.   The backlight assembly or passive display device according to claim 21, wherein the at least one input area and the at least one output area are provided on the same side of the layer.   72. The backlight assembly or passive display device of claim 71, wherein the at least one input area and the at least one output area are substantially collinear.   The backlight assembly is designed and configured to enter the backlight assembly while the illumination light propagates in a first direction and exit the backlight assembly while propagating in the first direction; 16. The backlight assembly or passive display device according to claim 1, 2, 14, or 15.   The backlight assembly is designed such that the illumination light enters the backlight assembly while propagating in a first direction, and exits the backlight assembly while propagating in a second direction different from the first direction. The backlight assembly or passive display device according to claim 1, 2, 14, or 15.   The backlight assembly includes a first facet and a second facet that is larger in size than the first facet, and the plurality of waveguides extend from the first facet to the second facet. 16. The backlight assembly or passive display device according to 14 or 15.   76. The backlight assembly or passive display device of claim 75, wherein the second facet is substantially parallel to the first facet.   76. The backlight assembly or passive display device of claim 75, wherein the second facet is substantially orthogonal to the first facet.   76. The backlight assembly or passive display device of claim 75, wherein the second facet and the first facet are substantially coplanar.   16. A backlight assembly or passive display device according to claim 1, 2, 14, or 15, wherein the backlight assembly is designed and configured to emit light originating from different sources in different directions.   16. A backlight assembly or passive display according to claim 1, 2, 14 or 15, wherein the backlight assembly is designed and configured to emit light originating from one source in at least two different directions. apparatus.   16. The backlight assembly or passive display device according to claim 1, 2, 14, or 15, wherein at least a few of the plurality of waveguides are single mode waveguides.   The backlight assembly or passive display device according to claim 1, 2, 14, or 15, wherein at least a few of the plurality of waveguides are multimode waveguides.   The backlight assembly or passive display device of claim 1, 2, 14, or 15, wherein at least a few of the plurality of waveguides comprise a photonic bandgap material.   The backlight assembly or passive display device according to claim 1, 2, 14, or 15, wherein the passive display panel includes a liquid crystal panel.   30. The backlight assembly or passive display device according to claim 16, 17 or 29, wherein at least one light source of the plurality of light sources is a light emitting diode.   30. The backlight assembly or passive display device according to claim 16, 17 or 29, wherein at least one of the plurality of light sources is a laser light source.

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