WO2007000713A1

WO2007000713A1 - High resolution interference-based liquid crystal projection/display system

Info

Publication number: WO2007000713A1
Application number: PCT/IB2006/052086
Authority: WO
Inventors: Marius I. Boamfa
Original assignee: Koninklijke Philips Electronics, N.V.; U.S. Philips Corporation
Priority date: 2005-06-29
Filing date: 2006-06-26
Publication date: 2007-01-04

Abstract

A display device (100, 800, 900) includes a plurality of pixels (150). Each of the pixels (150) has a first electrode (215, 515, 615), a second electrode (255, 555, 655) opposing the first electrode (215, 515, 615), a first optical path, and a second optical path. When a first voltage is applied between the first (215, 515, 615) and second (255, 555, 655) electrodes of a selected pixel (150), light passing through the first optical path of the selected pixel (150), and light passing through the second optical path (150) of the selected pixel, add constructively. When a second voltage is applied between first (215, 515, 615) and second (255, 555, 655) electrodes of the selected pixel (150), light passing through the first optical path of the selected pixel (150), and light passing through the second optical path of the selected pixel (150), add destructively to substantially cancel each other.

Description

HIGH RESOLUTION INTERFERENCE-BASED LIQUID CRYSTAL PROJECTION/DISPLAY SYSTEM

This invention pertains to the field of display devices, and more particularly, to liquid crystal display device where pixels are controlled to be turned on and off based on interference between portions of the light passing through the pixel.

Liquid crystal display (LCD) devices are becoming an increasing popular option for projection and direct- view displays. Sales of LCD devices are in the billions of dollars per year, and LCD devices are now challenging cathode ray tube (CRT) devices for supremacy in the display market. It is forecast that LCDs will become the dominant display technology over the next few years.

A standard LCD device includes at least an LC panel, a polarizer, and a second polarizer acting as an analyzer. The polarizer polarizes light passing impinging on the LC layer of the so that it has a single desired polarization. As the polarized light passes through the LC layer, the polarization is modulated to impress an image on the light. In the simplest case, the LC layer selectively either passes the light without any change in polarization, or passes the light with a 90 degree (orthogonal) rotation of the polarization. The modulated light is then passed through the analyzer to transform the modulated polarization into a change in light intensity. Again, in the simplest case, light having one of the two selected polarization states substantially passes through the analyzer, while light having the other (orthogonal) polarization does not pass through the analyzer. This may be referred to as "polarization extinction" and is the fundamental principal upon which these standard LCD devices operate. All of these standard LCD devices require a proper treatment of the confining surfaces of the LC panel to provide precise orientation control of the LC material.

However, these standard LCD devices suffer from some disadvantages and performance limitations. For one thing, as mentioned above these devices require the use of polarizers. These polarizers attenuate the intensity of the light that passes therethrough, thereby reducing the brightness of the display. Furthermore, these standard LCD devices typically include a plurality of spacers between the top and bottom substrates of the LC panel to maintain the mechanical integrity of the device. Also, in these devices a space between pixels is required to separate and isolate the pixel electrodes. Both of these factors reduce the effective display area of the device and also decrease the available brightness. Moreover, the LC layer must have a sufficient thickness for the molecular structures required to change the polarization of the light passing therethough by 90 degrees. The thickness of the LC layer also increases the pixel voltages required to reorient the LC molecules to orthogonally modulate the polarization of the light. Furthermore, the operating speed of the device is limited by the time required to reorient the LC layer to orthogonally modulate the polarization of the light.

Accordingly, it would be desirable to provide an LCD device with a simpler design, capable of operating without a polarizer. It would also be desirable to provide an LCD device capable of using all of the area of the display panel. It would be further desirable to provide an LCD device which can be made thinner, and can operate at lower pixel voltage levels. The present invention is directed to addressing one or more of the preceding concerns. In one aspect of the invention, a liquid crystal display device comprises a first substrate having a plurality of first electrodes disposed thereon defining pixels of the display device; a second substrate having a second electrode disposed thereon; an optically transparent material disposed between the first and second substrates, the optically transparent material having a plurality of pockets therein, at least one of the pockets corresponding to each of the pixels defined by the first electrodes; and liquid crystal material disposed in each of the plurality of pockets. When a first voltage is applied between the second electrode and the first electrode of a selected pixel, light passing through the liquid crystal material of the selected pixel, and light passing through a portion of the optically transparent material surrounding the liquid crystal material of the selected pixel, add constructively. Meanwhile, when a second voltage is applied between the second electrode and the first electrode of a selected pixel, the light passing through the liquid crystal material of the selected pixel, and the light passing through the portion of the optically transparent material surrounding the liquid crystal material of the selected pixel, add destructively to substantially cancel each other. In another aspect of the invention, a liquid crystal display device comprises a plurality of first electrodes defining pixels of the display device; a second electrode; and a plurality of physically isolated pockets of liquid crystal material disposed between the first electrodes and the second electrode, at least one of the pockets corresponding to each of the pixels defined by the plurality of first electrodes.

In yet another aspect of the invention, a display device comprises a plurality of pixels, each of the pixels having a first electrode; a second electrode opposing the first electrode; a first optical path; and a second optical path. When a first voltage is applied between the first and second electrodes of a selected pixel, light passing through the first optical path of the selected pixel, and light passing through the second optical path of the selected pixel, add constructively. Meanwhile, when a second voltage is applied between first and second electrodes of the selected pixel, light passing through the first optical path of the selected pixel, and light passing through the second optical path of the selected pixel, add destructively to substantially cancel each other.

FIG. 1 shows a top view of a portion of a liquid crystal (LC) panel of a liquid crystal display (LCD) device; FIG. 2 shows a cross-sectional schematic view of a first embodiment of the LC panel of FIG. 1;

FIG. 3 shows a top view of a single pixel of the LC panel of FIG. 1;

FIG. 4 shows a cross-sectional schematic view of the pixel of FIG. 3;

FIG. 5 shows a cross-sectional schematic view of a second embodiment of the LC panel of FIG. 1;

FIG. 6 shows a cross-sectional schematic view of another embodiment of an LC panel;

FIG. 7 shows a cross-sectional schematic view of a single pixel of the LC panel of FIG. 6; FIG. 8 shows a top view of a portion of another embodiment of an LC panel of an

LCD device;

FIG. 9 shows a top view of a portion of yet another embodiment of an LC panel of an LCD device.

FIG. 1 shows a top view of a portion of a liquid crystal (LC) panel of a liquid crystal display (LCD) device 100. The LCD device 100 includes an optically transparent material 110 having formed therein a plurality of pockets 120. Each of the pockets 120 is filled with a liquid crystal material 125. Beneficially, each of the pockets 120 of liquid crystal material 125 corresponds to one pixel 150 of the LCD device 100. That is, at a minimum each pixel 150 of the LCD device 100 includes one pocket 120 of liquid crystal material 125. However, it should be understood that a single pixel 150 may include more than one pocket 120 of liquid crystal material 125. It also should be understood that in FIG. 1 the dotted lines do not exist in reality or denote any physical separation in the structure of the device 100, but rather are shown as guides for the eye to highlight the hexagonal arrangement of the pixels 150.

In one arrangement, the LCD 100 of FIG. 1 may be a single color light modulator in a three-panel LCD color projection system. For example, the three-panel LCD color projection system may include three LCDs 100, each being adapted to receive light (e.g., from a laser light source) having one of the three colors red, green, or blue. In that case, the LCD device 100 may be a liquid crystal on silicon (LCOS) type device. Light modulated by the three LCDs 100 may then be suitably combined and then projected onto a display screen to produce a desired color image. FIG. 2 shows a cross-sectional schematic view of a first embodiment 200 of the LC panel of FIG. 1. The LC panel 200 includes first and second substrates 210, 250 having respective first and second electrodes 215 and 255 disposed thereon, optically transparent material 110 between the first and second substrates 210, 250 and having therein a plurality of pockets 120, liquid crystal material 125 disposed in each of the pockets 120, and an alignment layer 230 disposed on the pockets 120 of LC material 125.

At least the first substrate 210 comprises an optically transparent material, such as glass, plastic, plexiglass, etc.

Beneficially, the first electrodes 215 are pixelated, there being a separate first electrode for each of the pixels 150 of the LC panel 200. Also beneficially, the second electrode 255 is common for all of the pixels 150 of the LC panel 200.

The LC panel 200 is for a reflective-type LCD device, which may be a reflective liquid crystal on silicon (LCOS) device. Accordingly, the first electrodes 215 are made of an optically transparent layer, such as indium tin oxide (ITO), and the second electrode 255 is made of a highly reflective material, such as a metal. Operationally light impinges on the LC panel 200 from a top side thereof, passing in order through the first substrate 210 and the first (transparent) electrodes 215, reflecting off the second electrode 255, and passing in order back through the first (transparent) electrodes 215 and the first substrate 210. Beneficially, the optically transparent material 110 is a solid material, such as SiO₂, plastic, plexiglass, etc. In that case, advantageously the optically transparent material 110 provides structural support for the LC panel 200, helping separate the first and second substrates 210 and 230 from each other. Optionally, in some embodiments the optically transparent material 110 may include a gas, such as air, nitrogen, etc.

As can be seen in FIG. 2, the pockets 120 of LC material 125 do not need to extend all the way to the second electrode 255.

FIG. 3 shows a top view of a single pixel 150 of the LC panel of FIG. 1. As can be seen in FIG. 3, the pixel 150 comprises a pocket 120 of LC material 125 surrounded by optically transparent material 110. In the embodiments of FIG. 1 and 3, the pixels 150 are laid out in a hexagonal pattern and the pockets 120 are cylindrical (they have a circular cross-section). In that case, beneficially the "width" of a pixel is equal to λ, a wavelength of the light illuminating the LCD device, as described in greater detail below. Also, the diameter of the pocket 120 is beneficially about 0.64λ. In that case, the surface area of the pixel 150 corresponding to the pocket 120 of LC material 125 is approximately the same as the surface area of the pixel 150 corresponding to the surrounding optically transparent material 110, each area being about 0.32λ².

FIG. 4 shows a cross-sectional view of the pixel 150 of FIG. 3. Operating principles of the LC panel 200 will now be explained with respect to FIG. 4. At the outset, monochromatic (or quasi-monochromatic light) light having a wavelength λ is directed to impinge on the pixel 150. Beneficially, the light is coherent light generated from a laser. Alternatively, with some possible degradation in performance, the light may be generated by a light emitting diode (LED). As the light impinges on the pixel 150, portions of the light pass through two distinct optical paths. The first optical path passes through the pocket 120 of LC material 125. The second optical path passes through the portion of optically transparent material 110 surrounding the pocket 120. After the light is reflected by the reflective second electrode 255, it passes once again through the pixel 150, a first portion passing back through the pocket 120 of LC material 125, and a second portion passing back through the portion of optically transparent material 110 surrounding the pocket 120.

Due to the difference in the refractive index of the LC material 125 and the surrounding optically transparent material 110, the two portions of the light may emerge back from the pixel 150 with different phases, depending upon the thickness of the pixel 150, the voltage applied to electrodes 215, 255 across the LC material 125, and the refractive index characteristics of the LC material 125 itself. When the phase difference between the two light portions passing through the two optical paths is 0, λ, or i*λ (where i is an integer), then the two light portions add together constructively. On the other hand, when the phase difference between the two light portions passing through the two optical paths is λ/2, 3λ/2, or m*λ/2 (where m is an odd integer), then the two light portions add together destructively. In the particular case where the pixel width is about λ, the surface area of the pocket 120 of LC material 125 is about half the total pixel surface area, and the phase difference is λ/2 the effect is maximum, namely, light impinging on such an LC pixel 150 would not be reflected back. The light intensity reflected back from the pixel 150 can be controlled by adjusting the orientation of the LC molecules inside the pocket 120 of LC material 125 via the voltage applied to the electrodes 215, 255.

Let Nl be the refractive index for the LC material 125 when a first voltage (e.g., 0 volts) is applied between electrodes 215 and 255, N2 be the refractive index for the LC material 125 when a second voltage (V_ON) is applied across electrodes 215 and 255, and N3 be the refractive index of the optically transparent material 110 surrounding the pocket 120. In that case, if N3 is chosen to be Nl, then a phase change of λ/2 between the two optical paths can be obtained when the thickness, T, of the layer of LC material 125 is: T= λ/(4*| N2-N1|). With typical LC materials and assuming light in the visible spectrum, the thickness T will typically range between 1-2 microns.

In this case, the bright state ("ON" pixel) is obtained for an applied voltage of zero volts, and the dark state ("OFF" pixel) is obtained when the voltage applied across electrodes 215 and 255 is sufficient to align the LC molecules of the LC material 125 ("normally white display"). An alternative embodiment can be realized where the dark state ("OFF" pixel) is obtained for an applied voltage of zero volts, and the bright state ("ON" pixel) is obtained when the voltage applied across electrodes 215 and 255 is sufficient to align the LC molecules of the LC material 125 ("normally black display"). In that case, N3 is selected to be equal to the refractive index N2 of the LC material 125 when the second voltage (e.g., V_ON) is applied between electrodes 215 and 255, and the thickness T of the LC layer is T= λ/(4*|N2-Nl|).

The description above assumes that when no electric field is applied across the ALC material, the LC molecules lie randomly arranged in the surface plane (the plane perpendicular to the impinging light) due to a simple alignment layer 230 that favors LC planar alignment (not planar uniaxial alignment). In this case, , and , where is the refractive index of the LC material for light polarized parallel to the director of the LC molecules, and is the refractive index of the LC material for light polarized in a direction perpendicular direction to the director of the LC molecules. Alternatively, the impinging light may be originally polarized, and the alignment layer 230 may produce a uniaxial planar alignment of the LC material 125. This adds some complexity to the alignment layer 125, and requires the use of a polarizer if the light is not already polarized light such as from a laser light source. In this case and . The advantage of such an arrangement is that the brightness of the LC panel

200 can be increased by a factor of two and the thickness T is decreased by a factor of two (because in this case ), yielding a consequential reduction in the switching time.

Advantageously, where the optically transparent material 110 surrounding the pocket 120 is a solid material, it provides an enhanced mechanical or structural stability to the LC panel 200.

Also advantageously, the first electrodes 215 only need to cover the area of the pockets 120 of LC material 125, and therefore are naturally isolated from the neighboring ones without decreasing the effective area of the LC panel 200. In other words, the 215 electrodes can be separated while the pixels 150 are all immediately adjacent to each other, without any separation space therebetween. Accordingly, the useable display area of the LC panel 200 is increased compared with LCD devices based on polarization extinction, and approaches 100%.

Furthermore, because the pockets 120 of the LC material 125 can be relatively thin (e.g., 1-2 microns) compared with the thickness of the LC layers in LCD devices based on polarization extinction, the required pixel electrode voltages are lower and the response time can be faster.

FIG. 5 shows a cross-sectional schematic view of a second embodiment 500 of the LC panel of FIG. 1. The LC panel 500 is for a transmissive-type LCD device. Accordingly, the elements of the LC panel 500 are the same as those of the LC panel 200 of FIG. 2, except: (1) the second electrodes 555 of the LC panel 500 comprise an optically transparent layer, such as indium tin oxide (ITO), rather than the reflective material of the second electrodes 255 of FIG. 2; (2) either the first or second electrodes 515 and 555 of the LC panel 500 may be pixelated; and (3) both first and second substrates 510 and 550 comprise an optically transparent material, such as glass, plastic, plexiglass, etc. The remainder of the components of the LC panel 500 being the same as those of the LC panel 200, a description thereof will not be repeated here.

Operationally, as the light impinges on the pixel 150, portions of the light pass through two distinct optical paths. The first optical path passes through the pocket 120 of LC material 125. The second optical path passes through the portion of optically transparent material 110 surrounding the pocket 120.

Due to the difference in the refractive index of the LC material 125 and the surrounding optically transparent material 110, the two portions of the light may pass through the pixel 150 with different phases, depending upon the thickness of the pixel 150, the voltage applied to electrodes 515, 555 across the LC material 125, and the refractive index characteristics of the LC material 125 itself. When the phase difference between the two light portions passing through the two optical paths is 0, λ, or i* λ (where i is an integer), then the two light portions add together constructively. On the other hand, when the phase difference between the two light portions passing through the two optical paths is λ/2, 3 λ/2, or m* λ/2 (where m is an odd integer), then the two light portions add together destructively. In the particular case where the pixel width is about λ, the surface area of the pocket 120 of LC material 125 is about half the total pixel surface area, and the phase difference is λ/2 the effect is maximum, namely, light impinging on such an LC pixel 150 would not be reflected back. The light intensity passing through the pixel 150 can be controlled by adjusting the orientation of the LC molecules inside the pocket 120 of LC material 125 via the voltage applied to the electrodes 515, 555.

Let Nl be the refractive index for the LC material 125 when a first voltage (e.g., 0 volts) is applied between electrodes 515 and 555, N2 be the refractive index for the LC material 125 when a second voltage (V_ON) is applied across electrodes 515 and 555, and N3 be the refractive index of the optically transparent material 110 surrounding the pocket 120. In that case, if N3 is chosen to be Nl, then a phase change of λ/2 between the two optical paths can be obtained when the thickness, T, of the layer of the LC material 125 is T = λ/(2*| N2-N1|). With typical LC materials and assuming light in the visible spectrum, the thickness will typically range between 1-2 microns. In this case, the bright state ("ON" pixel) is obtained for an applied voltage of zero volts, and the dark state ("OFF" pixel) is obtained when the voltage applied across electrodes 515 and 555 is sufficient to align the LC molecules of the LC material 125 ("normally white display"). An alternative embodiment can be realized where the dark state ("OFF" pixel) is obtained for an applied voltage of zero volts, and the bright state ("ON" pixel) is obtained when the voltage applied across electrodes 515 and 555 is sufficient to align the LC molecules of the LC material 125 ("normally black display"). In that case, N3 is selected to be equal to the refractive index N2 of the LC material 125 when the second voltage (e.g., V_ON) is applied between electrodes 515 and 555, and the thickness T of the LC layer is λ/(2*| N2-Nl|).

FIG. 6 shows a cross-sectional schematic view of another embodiment 600 of an LC panel. The LC panel 600 includes first and second substrates 610, 650, first and second electrodes 615 and 655, and an alignment layer 630. Optionally, the LC panel 600 includes a reflective layer 675 disposed on either side of the first substrate 610, or between the alignment layer 630 and the second substrate 650 as will be explained in further detail below. The second substrate 650 has a plurality of pockets 620 formed therein. Each of the pockets 620 is filled with a liquid crystal material 625. Beneficially, each of the pockets 620 of liquid crystal material 125 corresponds to one pixel 150 of the LC panel 600. That is, at a minimum each pixel 150 of the LCD panel 600 includes one pocket 620 of liquid crystal material 125. However, it should be understood that a single pixel 150 may include more than one pocket 620 of liquid crystal material 125.

The first substrate 610 comprises an optically transparent material, such as glass, plastic, plexiglass, etc. The second substrate 650 may comprise glass, plastic, or a silicon substrate.

Beneficially, the first electrodes 615 are pixelated, there being one separate first electrode for each of the pixels 150 of the LC panel 600. Also beneficially, the second electrode 655 is common for all of the pixels 150 of the LC panel 600.

The LC panel 600 is for a reflective-type LCD device, which may be a reflective liquid crystal on silicon (LCOS) device. Accordingly, the first electrodes 615 are made of an optically transparent layer, such as indium tin oxide (ITO), and the second electrode 655 is made of a highly reflective material, such as a reflective metal. FIG. 7 shows a cross-sectional schematic view of a single pixel 150 of the LC panel of FIG. 6.

Operating principles of the LC panel 600 will now be explained with respect to FIG. 7. At the outset, monochromatic (or quasi-monochromatic light) light having a wavelength λ is directed to impinge on the pixel 150. Beneficially, the light is coherent light generated from a laser. Alternatively, with some possible degradation in performance, the light may be generated by a light emitting diode (LED). As the light impinges on the pixel 150, portions of the light pass through two distinct optical paths. The first optical path passes through the pocket 620 of LC material 125. The second optical path does not pass through the pocket 620 of LC material 125.

After the first portion of the light passes through the pocket 620 of LC material 625, it is reflected by the reflective second electrode 655 and passes back through the pocket 120 of LC material 125. Meanwhile, the second portion of the light does not pass through the pocket 620 of LC material 125 and is reflected either by the top portion of the reflective second electrode 655, or by the optional reflective layer 675 disposed on either side of the first substrate 610, or between the alignment layer 630 and the second substrate 650.

Depending upon the refractive index and thickness, T, of the LC material 125, the two portions of the light may emerge back from the pixel 150 with different phases, depending upon the voltage applied to electrodes 615, 655 across the LC material 125. When the phase difference between the two light portions passing through the two optical paths is 0, λ, or i* λ (where i is an integer), then the two light portions add together constructively. On the other hand, when the phase difference between the two light portions passing through the two optical paths is λ/2, 3 λ/2, or m* λ/2 (where m is an odd integer), then the two light portions add together destructively. In the particular case where the pixel width is about λ, the surface area of the pocket 620 of LC material 125 is about half the total pixel surface area, and the phase difference is λ/2 the effect is maximum, namely, light impinging on such an LC pixel 150 would not be reflected back. The light intensity reflected back from the pixel 150 can be controlled by adjusting the orientation of the LC molecules inside the pocket 620 of LC material 125 via the voltage applied to the electrodes 615, 655.

Let Nl be the refractive index for the LC material 125 when a first voltage (e.g., 0 volts) is applied between electrodes 615 and 655, N2 be the refractive index for the LC material 125 when a second voltage (V_ON) is applied across electrodes 615 and 655, and T be the thickness of the layer of LC material 125. In that case, then a phase change of λ/2 between the two optical paths can be obtained when the thickness, T, of the layer of LC material 125 is: T= λ/(4*| N2-N1|). With typical LC materials and assuming light in the visible spectrum, the thickness T will typically range between 1-2 microns. In the embodiments of FIG. 1 and 3, the pixels 150 are laid out in a hexagonal pattern and the pockets 120 are cylindrical (circular cross-section). However, it should be understood that other patterns and arrangements are possible. FIGs. 8 and 9 show top views of portions of other embodiments of an LC panel of LCD devices 800 and 900, respectively. Beneficially, in each of these various embodiments, approximately 50% of the surface area of each pixel is "active," i.e., comprises the pockets of LC material, and the remaining approximately 50% of the surface area of each pixel is "passive" (in an optical path where the light does not pass through the LC material). Beneficially, the patterning shown in FIGs. 8 and 9 is done as a sub-wavelength scale. Lower resolution devices can be realized by connected the first (pixel) electrodes of the individual pixels to form larger structures.

While preferred embodiments are disclosed herein, many variations are possible which remain within the concept and scope of the invention. Such variations would become clear to one of ordinary skill in the art after inspection of the specification, drawings and claims herein. The invention therefore is not to be restricted except within the spirit and scope of the appended claims.

Claims

CLAIMS:

1. A liquid crystal display device (100, 800, 900), comprising: a first substrate (210, 510) having a plurality of first electrodes (215, 515) disposed thereon defining pixels (150) of the display device (100, 800, 900); a second substrate (250, 550, 650) having a second electrode (255, 555) disposed thereon; an optically transparent material (110) disposed between the first (210, 510) and second (510, 550) substrates, the optically transparent material (110) having a plurality of pockets (120) therein, at least one of the pockets (120) corresponding to each of the pixels (150) defined by the first electrodes (215); liquid crystal material (125) disposed in each of the plurality of pockets (120); wherein when a first voltage is applied between the second electrode (255, 555) and the first electrode (215, 515) of a selected pixel (150), light passing through the liquid crystal material (125) of the selected pixel (150), and light passing through a portion of the optically transparent material (110) surrounding the liquid crystal material (125) of the selected pixel (150), add constructively, and wherein when a second voltage is applied between the second electrode (255, 555) and the first electrode (215, 515) of a selected pixel (150), the light passing through the liquid crystal material (125) of the selected pixel (150), and the light passing through the portion of the optically transparent material (110) surrounding the liquid crystal material (125) of the selected pixel (150), add destructively to substantially cancel each other.

2. The device (100, 800, 900) of claim 1, wherein the optically transparent material (110) is a solid material.

3. The device (100, 800, 900) of claim 1, wherein the optically transparent material (110) includes a gaseous material.

4. The device (100, 800, 900) of claim 1 further comprising an alignment layer (230, 630) adapted to generate a planar alignment of liquid crystal molecules in the liquid crystal material (125).

5. The device (100, 800, 900) of claim 1 further comprising an alignment layer (230, 630) adapted to generate a planar uniaxial alignment of liquid crystal molecules in the liquid crystal material (125).

6. The device (100, 800, 900) of claim 1, wherein the first electrodes (215) are transparent and the second electrode (255) is reflective.

7. The device (100, 800, 900) of claim 6, wherein the light passing through the liquid crystal material (125) of the selected pixel (150) has a wavelength of λ, the index of refraction of the liquid crystal material (125) is Nl when the first voltage is applied between the second electrode (255) and the first electrode (215) of a selected pixel (150), the index of refraction of the liquid crystal material (125) is N2 when the second voltage is applied between the second electrode (255) and the first electrode (215) of the selected pixel (150), a thickness of the liquid crystal material (125) is m*λ/(4*| N2-N1|), where m is an odd integer, and wherein the index of refraction of the optically transparent material

(110) is N3 =N1 when the first voltage corresponds to an on state for the selected pixel (150), and N3=N2 when the second voltage corresponds to an on state for the selected pixel (150).

8. The device (100, 800, 900) of claim 1, wherein a ratio of an area of a pixel (150) comprising the liquid crystal material (125) to an area of the pixel comprising the optically transparent material (110) surrounding the liquid crystal material is about 50%.

9. The device (100, 800, 900) of claim 1, wherein the first (515) and second (555) electrodes are transparent.

10. The device (100, 800, 900) of claim 9, wherein the light passing through the liquid crystal material (125) of the selected pixel (150) has a wavelength of λ, the index of refraction of the liquid crystal material (125) is Nl when the first voltage is applied between the second electrode (255) and the first electrode (215) of a selected pixel (150), the index of refraction of the liquid crystal material (125) is N2 when the second voltage is applied between the second electrode (255) and the first electrode (215) of a selected pixel (150), a thickness of the liquid crystal material (125) is m*λ/(2*| N2-N1|), where m is an odd integer, and wherein the index of refraction of the optically transparent material (110) is N3 =N1 when the first voltage corresponds to an on state for the selected pixel (150), and N3=N2 when the second voltage corresponds to an on state for the selected pixel (150).

11. A liquid crystal display device (100, 800, 900), comprising: a plurality of first electrodes (215, 515, 615) defining pixels (150) of the display device (100, 800, 900); a second electrode (255, 555, 655); and a plurality of physically isolated pockets (120, 620) of liquid crystal material (125) disposed between the first electrodes (215, 515, 615) and the second electrode (255, 555, 655), at least one of the pockets (120, 620) corresponding to each of the pixels (1500 defined by the plurality of first electrodes (215, 515, 615).

12. The device (100, 800, 900) of claim 11, further comprising a reflective layer (655, 675) disposed at an area of each pixel (150) surrounding the pockets (620) of liquid crystal material (125).

13. The device (100, 800, 900) of claim 11, wherein the plurality of physically isolated pockets (620) of liquid crystal material (125) are disposed in a substrate (650).

14. The device (100, 800, 900) of claim 11, wherein the first electrodes (215, 615) are transparent and the second electrode (255, 655) is reflective.

15. The device (100, 800, 900) of claim 11, further comprising an optically transparent material (110) surrounding the pockets (120) of liquid crystal material (125).

16. The device (100, 800, 900) of claim 15, further comprising a laser illuminating the pixels (150), wherein the laser has a wavelength of λ, the index of refraction of the liquid crystal material (125) is Nl when the first voltage is applied between the second electrode (255, 555) and the first electrode (215, 515) of a selected pixel (150), the index of refraction of the liquid crystal material (125) is N2 when the second voltage is applied between the second electrode (255, 555) and the first electrode (215, 515) of a selected pixel (150), a thickness of the liquid crystal material (125) is m*λ/(4*| N2-N1|), where m is an odd integer, and wherein the index of refraction of the optically transparent material (110) is N3 =N1 when the first voltage corresponds to an on state for the selected pixel (150), and N3=N2 when the second voltage corresponds to an on state for the selected pixel (150).

17. A display device (100, 800, 900), comprising: a plurality of pixels (150), each of the pixels (150) having a first electrode (215, 515, 615); a second electrode (255, 555, 655) opposing the first electrode (215, 515, 615); a first optical path; and a second optical path, wherein when a first voltage is applied between the first (215, 515, 615) and second (255, 555, 655) electrodes of a selected pixel (150), light passing through the first optical path of the selected pixel (150), and light passing through the second optical path (150) of the selected pixel, add constructively, and wherein when a second voltage is applied between first (215, 515, 615) and second (255, 555, 655) electrodes of the selected pixel (150), light passing through the first optical path of the selected pixel (150), and light passing through the second optical path of the selected pixel (150), add destructively to substantially cancel each other.

18. The device (100, 800, 900) of claim 17, wherein the first electrode (215, 615) is transparent and the second electrode (255, 655) is reflective.

19. The device (100, 800, 900) of claim 17, wherein the first (515) and second (555) electrodes are transparent.

20. The device (100, 800, 900) of claim 17, wherein the first optical path passes though a pocket (120, 620) of liquid crystal material (125), and the second optical path does not pass through any LC material (125).