Light modulator for optical image projection

A spatial light modulator 100 comprising an array-type liquid crystal panel 115, a polarization beam splitter 120, an oblique wave plate 130 and a converging lens 135. The polarization beam splitter is orientated to direct a source light 125 towards a reflective planar surface 127 of the array-type liquid crystal panel. The oblique wave plate and converging lens are located between the polarization beam splitter and the array-type liquid crystal panel. The converging lens is configured to direct light from the reflective planar surface onto a facing surface 125 of the polarization beam splitter.

TECHNICAL FIELD

This application is directed, in general, to optical image projection systems having a spatial light modulator array-type liquid crystal panel.

BACKGROUND

There is great interest in using array-type liquid crystal panels (LCP) as a spatial light modulator in the light modulator of an optical image projection system. Typically, polarized light passes through a polarization beam splitter (PBS) to the LCP. Individual liquid crystal pixels of the array forming the LCP can be activated or non-activated to cause the light to be reflected off of the LCP with the same polarization state or the orthogonal (e.g., opposite) polarization state, respectively, as the incoming light. Depending upon the configuration of the system, one linear polarization of, which is light reflected off the LCP, will pass through the PBS to projection optics and thereby provide a bright-field pixel. The orthogonal linear polarization component of the light will pass through the PBS in the direction orthogonal to the projection optics and thereby will provide a dark-field pixel.

SUMMARY

One embodiment provides a spatial light modulator. The modulator comprises an array-type liquid crystal panel. The modulator comprises a polarization beam splitter. The polarization beam splitter is orientated to direct source light towards a planar reflective surface of the array-type liquid crystal panel. The modulator comprises an oblique wave plate located between the polarization beam splitter and the array-type liquid crystal panel. The modulator comprises a converging lens located between the polarization beam splitter and the array-type liquid crystal panel. The converging lens is configured to direct light reflected from the planar reflective surface to a facing surface of the polarization beam splitter.

The device comprises an array-type liquid crystal panel, a polarization beam splitter an oblique wave plate and a converging lens. The polarization beam splitter is orientated to direct source light towards a reflective planar surface of the array-type liquid crystal panel. The oblique wave plate and a lens are located between the polarization beam splitter and the array-type liquid crystal panel. The converging lens is configured to direct light reflected from the reflective planar surface to a facing surface of the polarization beam splitter.

Another embodiment provides optical image projection system. The system comprises a light source configured to emit a source light. The system comprises a spatial light modulator optically coupled to receive the source light. The spatial light modulator includes an array-type liquid crystal panel. The spatial light modulator includes a polarization beam splitter. The polarization beam splitter is orientated to direct the source light towards a reflective planar surface of the array-type liquid crystal panel. The spatial light modulator includes an oblique wave plate located between the polarization beam splitter and the array-type liquid crystal panel. The spatial light modulator includes a converging lens located between the polarization beam splitter and the array-type liquid crystal panel. The converging lens is configured to direct the reflected light from the reflective planar surface to a facing surface of the polarization beam splitter. The system comprises projection optics configured to receive light output from the polarization beam splitter.

DETAILED DESCRIPTION

Some LCP projection systems can suffer from poor image contrast. Additionally, such systems are not readily amenable to miniaturization because certain optical components must be kept large enough to capture substantially all of the light that divergently reflects off of the LCP panel.

It has been discovered that the sizes of optical components, such as the PBS and projection optics, can be reduced by situating a converging lens in the light path between the LCP and the PBS. The term converging lens as used herein is defined as a positive lens (e.g., a field lens) that is located closer to the image forming surface (e.g., the LCP surface) than any other lens. That is, any other lens or lenses in the projection optics of the optical module are closer to the target projection surface (e.g., a screen) than the converging lens. Unfortunately, a converging lens used alone, or with a quarter wave plate, may not provide the desired level of projected image contrast.

Embodiments of the disclosure benefit from the realization that substantial light leakage can occur when the polarized state of some light arriving at the reflecting surface of the PBS is not the same as the polarization state that can be rejected by the PBS. In particular, the polarization state of light reflected from non-activated pixels of the LCP and focused through the converging lens is altered. The polarization state is altered for light rays that have incident angles that are not normal to the PBS surface facing the LCP, with respect to the polarization state to be rejected by the PBS. This alteration in polarization state is such that at least some of the light that it is desirable to reject will instead can pass through the PBS to the projection optics of the projection system. This effect, referred to herein as polarization light ray skewing (PLRS), contributes to poor contrast.

It was also recognized that there can be other factors that contribute to poor contrast. One contributor can be the polarization rotation attributable to the presence of the converging lens, due to the ray trajectory produced by the double pass through the converging lens and reflection by the non-activated pixels of the LCP. Another contributor can be non-ideal LCP characteristics. In the non-activated state, an ideal LCP preserves the polarization state of the reflected light to be the same as the polarization state of the incident light. In contrast real (e.g., non-ideal) LCP pixels can be birefringent in the non-activated state and thus, can alter the polarization state (e.g., linear polarization state) of the incident light. Thus, a polarization component that is not rejected by the PBS is generated, leading to poor contrast.

It was also discovered, as part of the present disclosure, that light leakage due to PLRS can be substantially reduced by situating an oblique wave plate (o-plate) in the light path between the LCP and the PBS. The term o-plate as used herein is defined as a birefringent material (e.g., an optically anisotropic medium such as calcite or quartz crystals) configured to have a smooth flat outer surfaces and having an optical axis that is neither parallel nor perpendicular to the outer surfaces.

Additionally, in some cases, the o-plate can be adjusted to compensate the polarization change due to the reflection from birefringent non-activated pixels of the LCP. For instance, the o-plate can be adjusted to change the orientation of the optical axis of the o-plate with respect to a horizontal plane of the o-plate. Alternatively, a thin compensating waveplate can be added to the o-plate. As a consequence, it is possible to decrease the amount the light reflected from an non-ideal LCP, and having the polarization component that cannot be rejected by the PBS from the projection path. In some cases, these measures can also advantageously improve image contrast without substantially increasing system size, e.g., by the addition of a separate compensating waveplate connected to, or part of, the LCP.

The combination of the o-plate and the converging lens can allow the production of a more compact (e.g., hand-held) projection system that is capable of producing images with a higher contrast than hither-to possible. The converging lens effectively directs light reflected from the LCP to propagate closer to the optical axis by reducing the spread of the reflected light. Thus, the sizes of optical components can be reduced to enable a more compact projector system. The o-plate can improve contrast by compensating for global PLRS effects. The o-plate can act on the altered polarization state of light reflected from non-activated pixels of the LCP so as to substantially return the light's polarization state to what it would be if the reflected light rays had formed a non-divergent beam (e.g., a normal incident angle to the PBS's surface). Consequently, the PBS is better able to reject light reflected from the non-activated pixels of the LCP thereby reducing the amount of projected light from dark-field pixels and thereby improve image contrast.

One embodiment of the disclosure is a light modulator device (e.g., a spatial light modulator). The configuration of the light modulator device can differ depending upon the polarization state of the light source and desired polarization state of light to be projected. For instance,FIG. 1Apresents a plan view of an example configuration of a light modulator device100, shown as part of an optical image projection system102. As illustrated inFIG. 1, embodiments of the system102can include a light source105and projection optics110that are optically coupled to the device100.

Some features of the image projection system102described herein and the methods of using these features to produce projected images may be described in one or more of: the above cited U.S. patent application Ser. No. 12/017,440; U.S. Pat. No. 7,440,158; U.S. patent application Ser. Nos. 12/017,984, 12/009,991, and 12/009,851, which were all filed on Jan. 22, 2008; and U.S. patent application Ser. Nos. 11/713,155, 11/681,376, and 11/713,483, which were all filed on Mar. 2, 2007; and U.S. patent application Ser. No. 12/357,734 entitled “Oscillating Mirror for Image Projection” to Gang Chen et al. filed on Jan. 22, 2009. The above-listed U.S. patent and the above-listed U.S. patent applications are incorporated herein by reference in their entirety.

The example device100shown inFIG. 1Acomprises a LCP115and a PBS120. The PBS120is orientated to direct a source light125towards a reflective planar surface127of the LCP105. The device100also comprises an o-plate130and a converging lens135. Both the o-plate130and the converging lens135are located between the LCP115and the PBS120. The converging lens135can be configured to direct light140,142(e.g., substantially all reflected light140,142) reflected from the reflective planar surface127of the LCP115onto an opposing (e.g., facing) surface145of the PBS110.

In some cases, such as shown inFIG. 1A, the o-plate130is located between the PBS120and the converging lens135. In other cases, the o-plate130is located between the converging lens135and the LCP115(not shown). In some cases, the former configuration (o-plate between the PBS and converging lens) provides substantially better contrast than the latter configuration (o-plate between the PBS and LCP) and therefore is a preferred embodiment. One of ordinary skill in the art would understand how to determine the optimal locations of the o-plate130and converging lens135, relative to each other, and to the LCP115and PBS120so as to maximize image contrast for either of these configurations, including e.g., maximizing the amount of light delivered to and reflected from the LCP115.

The LCP115comprises a plurality of pixels150that can be individually activated by applying an electric field across individual pixels150(e.g., via transparent indium tin oxide electrodes adjacent thereto). The light140reflected from activated pixels150has the opposite polarization state as compared to the polarization state of the source light125. For example, when the light source105emits vertically polarized source light125, then the reflected light140from activated pixels150is horizontally polarized.

In comparison, the polarization state of reflected light142from non-activated pixels150with an incident angle155that is normal with respect (e.g. 90 degree±5 degrees) to the PBS's opposing surface145is not substantially altered. However, as noted above, due to the PLRS effect, the polarization state of reflected light142from non-activated pixels150can be altered when the light140has a non-normal incident angle155(e.g., more than ±5 degrees). For instance, continuing with the same example of when the source light125is vertically polarized a substantial portion of reflected light142from non-activated pixels150and a non-normal incident angle155can be horizontally polarized. Because reflected light142from these non-activated pixels150has the same polarization state as the reflected light140from activated pixels150, the light contrast between activated and non-activated pixels150is decreased.

Embodiments of the o-plate130can have planar outer surfaces160,162that are parallel to the surface145of the PBS120. One surface160opposes (e.g., faces) the surface145of the PBS120and the other surface162opposes (e.g., faces) the reflective surface127(e.g., a planar reflective surface) of the LCP115. The planar outer surfaces160,162of the o-plate can be substantially perpendicular to the source light125that passes from the PBS120to the LCP115.

The o-plate130is important for reducing the amount of reflected light142from certain non-activated pixels150that otherwise would detrimentally pass through the PBS110and reach the projection optics110of the system102thereby reducing image contrast. The o-plate130, by definition, has an optical axis165with an angle167that is neither parallel nor perpendicular with respect to the outer planar surface160of the o-plate130. The outer planar surface160is located so as to receive the light140,142reflected by the LCP115. One skilled in the art would be familiar with various methods to characterize the optical axis165of the o-plate130. For instance, one could measure the retardance of collimated light that passes through the o-plate130, as a function of different incident angles (or polarizations) of the collimated light, to determine incident angle where the minimum retardance occurs.

In some preferred embodiments, the o-plate130has an optical axis165making an angle167that ranges from about 16 to 36 degrees, and more preferably, about 24 to 28 degrees. O-plates130having such characteristics can be particularly effective at compensating the polarization state of the light reflected142from non-activated pixels150to the same polarization state it would have if the incident angle155of reflected light142was normal to the PBS's opposing surface145(vertical polarized light in the above example).

As noted above, the o-plate130can be configured to at least partially compensate polarization changes due to the reflection from the birefringent non-activated pixels of the LCP115having non-ideal characteristics. In one embodiment, for instance, the orientation of the optical axis165of the o-plate130can be adjusted, by rotating the o-plate130, to compensate the polarization change of the incident light140, which occurs upon reflection off of the non-ideal birefringent pixels150of the LCP115. The polarization of the reflected light142can thereby be at least partially restored to the polarization state that it would have if the non-activated pixels150were ideal.

FIG. 1Bpresents a perspective view of an example configuration of the o-plate130, substantially along view lines B-B shown inFIG. 1A, to illustrate an example adjustment in the orientation of the optical axis165of the o-plate130.FIG. 1Billustrates that a planar surface170of the o-plate130, defined by the optical axis165of the o-plate130and the normal axis171(also depicted inFIG. 1A) to the o-plate130, has an angle172(e.g., by rotating the o-plate as shown by the curved arrow inFIG. 1B) in the range from about 3 to 4 degrees with respect to a horizontal plane173of the device100(e.g., the horizontal plane depicted in the plan view ofFIG. 1A). One skilled in the art would understand how to adjust the angle172to different values, depending upon the extent of non-ideality of the birefringent pixels150(FIG. 1A).

In still other embodiments, the o-plate130can alternatively, or additionally, further include a thin waveplate layer175(e.g., a second waveplate) thereon (e.g., on surface170of the o-plate130, shown inFIG. 1B). For instance, in some embodiments the additional waveplate layer175can have a thickness176in the range of about 1 to 10 microns. The thin waveplate layer175can have the appropriate optical axis177orientation and retardance, which are different from that of the o-plate130, to improve compensation of the birefringence of the non-activated LCP pixels150. E.g., at least one of the retardance or angle178of the optical axis177are at least about 10 percent different than the corresponding values for the o-plate130. For instance, in some preferred embodiments, the orientation of the optical axis177corresponds to an angle178of about 45 degrees with respect to a vertical axis179(i.e. an axis perpendicular to the horizontal plane173). In some preferred embodiments, the birefringence of the material of the waveplate layer175is of the opposite sign as that of the non-activated LCP pixels150. In some cases, optical axes of the LCP pixels150and the waveplate layer175may be approximately aligned. In some preferred embodiments, the retardance of the layer175is in a range from about 3 to 5 nanometers. One skilled in the art would understand how to adjust the thickness176and orientation of the thin waveplate layer175so as to compensate the non-ideality of the birefringent pixels150.

The thickness of the o-plate130can also affect the compensation of the polarization state of the light reflected142from the non-activated pixels150with non-normal incident angles155. For instance, in some preferred embodiments, the o-plate130has a thickness180(FIG. 1A) in a range of about 3 to 6 microns. However, depending upon the type of optically anisotropic crystal material the o-plate is composed of, a different thickness180value can be used to provide the desired half-wave light retardance.

Sometimes, the manufacture of o-plate thicknesses180of about 5 microns or greater can be difficult. In such cases, the angle167optical axis165and thickness180of the o-plate130can be cooperatively adjusted to achieve a balance between improved image contrast and ease of manufacturing the o-plate130. These principles are illustrated below for some example embodiments that provide acceptable levels of ANSI image contrast (e.g., about 500:1 or greater). The term ANSI contrast as used herein refers to ratio of the average reflected light intensity from the activated pixels in 8 rectangles divided by the average reflected light intensity from the non-activated pixels in the other 8 rectangles with the activated and non-activated pixel sections arranged in a rectangular 4×4 checkerboard pattern. In some embodiments, an ANSI contrast of about 600:1 can be obtained using an optical axis angle167in the range of about 24 to 28 degrees and thickness180in the range of about 4 to 4.2 microns. In other embodiments, an ANSI contrast of about 1500:1 can be obtained using an optical axis angle167in the range of about 29 to 31 degrees and thickness180of about 5.6 microns. In other embodiments, an ANSI contrast of about 500:1 can be obtained using an optical axis angle167angle of 26±1 degrees and thickness180in the range of about 3.5 to 4 microns.

The LCP115can be composed of any conventional material that permits the manipulation of polarized light in the manner described herein. For example, in some preferred embodiments the LCP115is a liquid crystal on silicon panel. In some embodiments, such as when a compact system102is desired, the LCP115has height and width dimensions on the order of 1 to several millimeters. For example, in some preferred embodiments of such a compact system102the LCP115has a height181and width182that both range from about 3 to 5 millimeters.

The converging lens135can be composed of any material that is transparent to the source light125and have any shape and dimensions that facilitate directing the reflected light140,142so as to substantially land on the opposing (e.g., facing) surface145of the PBS120(e.g., about 90 percent or more of the reflected light). Continuing with the example compact system102, in some preferred embodiments, the converging lens135is a positive (e.g., converging) glass or plastic lens having a focal length of about 13 mm. In some preferred embodiments, to facilitate having a compact system102, the converging lens135has a diameter185that ranges from about 1 to 1.2 times the larger of the height and width dimensions181,182of the reflective planar surface127. Consider, e.g., the case when the reflective planar surface127has a rectangular shape with a height181and width182of about 3 and 5 mm, respectively. Some preferred embodiments of the converging lens135have a diameter185in the range of about 5 to 6 mm.

Because the converging lens135can reduce the spreading of light140,142reflected from the LCP115, the dimensions of the PBS120can also be reduced, thereby facilitating a compact system102design. Continuing with the above example compact system102, in some preferred embodiments, the PBS120has height, thickness and width dimensions190,192,194that range from about 1 to 1.2 times the larger of the height and width dimensions181,182of the reflective planar surface127. In the case when larger of the height and width dimensions181,182equals about 5 mm, the PBS's height, width and depth dimensions190,192,194dimension are in the range of about 5 to 6 mm. Similarly, height and width dimension196,198of the o-plate130can range from about 1 to 1.2 times the larger of the height and width dimensions181,182.

FIG. 1Apresents an example configuration of the device100and system102where the source light125is vertically polarized light and the PBS120is configured to reflect the vertically polarized light125to the LCP115. In such configurations, horizontally polarized light140is reflected from the LCP115(e.g., activated pixels150) and transmitted straight through the PBS120to the projection optics120of the system102. The vertically polarized light142reflected from the LCP115(e.g., non-activated pixels150), including light compensated by the o-plate130, is reflected through the PBS120to the origin of the source light125(e.g., the light source105).

FIG. 2presents a plan view of an alternative example configuration of a light modulator device200(e.g., spatial light modulator), also shown as part of an optical image projection system202of the disclosure. The same reference numbers as used inFIG. 1Aare used to depict analogous components and features of the device200and system202. In this example configuration of the device200and system202, the source light125can be horizontally polarized light and the PBS120can be configured to transmit the horizontally polarized light125straight through the PBS120to the LCP115. In such configurations, vertically polarized light140reflected from the LCP115(e.g., activated pixels150) is reflected by the PBS120to the projection optics120of the system102. Horizontally polarized light142reflected from the LCP115(e.g., non-activated pixels150), including light compensated by the o-plate130, passes through the PBS120to origin of the source light125.

Another embodiment is an optical image projection system300. In some preferred embodiments, the system300is configured as a hand-held projection system. Non-limiting examples include cell phones, personal digital assistants, or media players.

FIG. 3presents a plan view of an example optical image projection system300that includes a light modulator device (e.g., spatial light modulator). For the purposes of illustration the device100configuration presented inFIG. 1Ais shown. However, other configurations such as the device200configuration presented inFIG. 2could also be used. For clarity the same reference number as used inFIG. 1Aare used to depict analogous features of the system300.

The system300comprises a light source105, the light modulator device100(e.g., spatial light modulator), and projection optics110. The light source is configured to emit a source light125, and the light modulator device100is optically coupled to the light source. For instance the device100can be configured to receive the source light125. For instance, the PBS120of the device100can be orientated to direct the source light125towards a reflective planar surface127of the LCP115. The LCP115, PBS120, o-plate130and converging lens135of the device100can have any of the configurations as described in the context ofFIG. 1or2.

The projection optics are configured to receive light output from the PBS120. The projection optics110can include mirrors, lens, polarizers or other optical components configured to further improve image contrast, and, to direct and direct images formed on the LCP115and facilitate passing the light140through the PBS120to a target projection surface310(e.g., a viewing surface). For clarity, only two components, one projection lens315and one polarizer317, of the projection optics110are depicted.

In some cases the target projection surface310is the surface of a projection screen320that is also part of the system300. In such embodiments the projection screen320is optically coupled to the projection optics110. For example, the projection screen320could be a front or rear projection screen that is aligned with the projection optics110. In other cases, however, the target projection surface310can be the surface of a structure that is external to the system300. For example, the projection screen320could be a wall (e.g., a white wall), table-top surface or other planar structure having a blank surface thereon that could serve as the target projection surface310. In some cases the surface310can be e.g., a diffusely reflecting planar surface.

Because the converging lens135decreases the spreading of light140,142reflected from the LCP115, more compact components315,317of the projection optics110can be used that otherwise possible, thereby facilitating a compact system300design. For example, in some cases, the components315,317of the projection optics110have dimensions that range from about 1 to 1.2 times the larger of the height and width dimensions181,182of the reflective planar surface (FIG. 1A). For instance, consider again the case where the reflective planar surface127of the LCP115have height and width dimensions181,182that both range from about 3 to 5 millimeters (FIG. 1A). In such instances, the projection lens315can have a diameter325in the range of about 5 to 6 mm and the polarizer317can have a height330and width332of about 5 to 6 mm.

In some embodiments, the light source105comprises one or more lasers340,342,344configured to emit the source light125as one of vertically polarized light or horizontally polarized light. In some embodiments the lasers340,342,344are configured to emit the source light125as linearly polarized light. For the embodiment depicted inFIG. 3, three lasers340,342,344are each configured to generate pulsed light of a designated color, e.g., red, green, and blue, respectively. The light output from the lasers340,342,344can be synchronized so that the PBS120receives a periodic train of different colors of light125. The light source105can further comprise a color combiner350configured to receive the source light125from the lasers340,342,344and direct the light125towards the PBS120. One skilled in the art would be familiar with the use of other optical components to further adjust the source light125that is directed to the PBS120, if necessary. For example, the light source105can further comprise lens, polarizers, mirrors, diffusers or other optical components (not shown).

Still another embodiment of the disclosure is a method of projecting an image. Any of the embodiments the devices100,200, or systems102,202,300discussed in the context ofFIGS. 1-3can be used to implement steps in the method. With continuing reference toFIGS. 1-3,FIG. 4presents a flow diagram of optical image projection.

The method includes a step405of directing a source light beam125(e.g., having a first polarization state) through a PBS120towards a reflective planar surface127of a LCP115. The PBS120has a planar surface125opposing (e.g., facing) the reflective planar surface127. In some preferred embodiments, the planar surface125is substantially parallel to the reflective planar surface127. On route to the LCP115, the light125also passes through the o-plate130and converging lens135.

The method400also includes a step410of forming an image on the reflective planar surface127. Forming the image (step410) includes reflecting (e.g., simultaneously reflecting) the source light125off of activated pixels150(e.g., a first set of pixels) in step412and the non-activated pixels150(e.g., a second set of pixels) in step415. The first and second sets of liquid crystal pixels cause reflected light140,142to be in different polarization states. For instance, the source light125reflected off of selected activated pixels150has a second polarization state that is substantially orthogonal (e.g., opposite) to the first polarization state of the source light125. The source light125reflected off of selected non-activated pixels has a substantially same polarization state as the first polarization state. However, as discussed above, due to PLRS, a portion of reflected light beams142from the non-activated pixels have a second polarization state that is opposite to the first polarization state of the source light125.

One skilled in the art would understand that the first and second polarization states are not fixed to the same values for all of the light beams125. Rather, each light beam125that is not along the optical axis (e.g., a non-normal incident angle155) would have its own particular reflected and transmitted first and second polarization states with respect to the PBS.

The method400further includes a step420of passing the reflected light beams140,142from the activated and the non-activated pixels150to (and through) a converging lens135. The converging lens135can be configured to direct substantially all of the reflected light beams140,142onto the opposing (e.g., facing) surface125of the PBS120.

The method400still further includes a step425of passing the reflected light beams140,142from the activated and the non-activated pixels150to (and through) an o-plate130. The o-plate130can be configured to compensate the reflected light beams142from the non-activated pixels150to have the first polarization state that is directed by the PBS toward the source light direction (e.g., the same first polarization state as the polarization state of the source light125). That is, the o-plate130acts to compensate the reflected light beams142from the non-activated pixels that have non-normal incident angles155so as to substantially return their polarization state to the first polarization state.

As further illustrated inFIG. 4, in some cases, the reflected light beams140,142pass to the converging lens135(step420) and then to the o-plate130(step425). In other cases, the reflected light beams140,142pass to the o-plate130(step425) and then to the converging lens135(step420).

The method400also includes a step430of passing the reflected light beams140,142(e.g., light reflected from a second set of non-activated pixels) from the converging lens135and the o-plate130through the PBS120such that the reflected light140,142having the first polarization state is directed to the source light125.

Preferably, the method includes a step435of passing the reflected light140,142from the first set of pixels (e.g., activated pixels150) through the PBS120to projection optics. For instance, step435can include passing the reflected light beams140having a second polarization state through the PBS120towards projection optics. The light can further pass to a viewing screen (e.g., a diffusely reflecting planar screen). In some cases passing the reflected light beams140having a second polarization state (step435) includes a step445of passing the reflected light140(having the second polarization state) from the activated pixels150straight through the PBS120to projection optics110(e.g.,FIG. 1A). In other cases, passing the reflected light beams140having a second polarization state (step435) includes a step447of reflecting the reflected light140from the activated pixels150through the PBS120to the projection optics110(e.g.,FIG. 2).

In other cases, reflected light from the second set of non-activated pixels152can be configured to pass through the PBS to the projection optics110, and, reflected light from the first set of activated pixels152can be configured to pass through the PBS120to the source light125.

In some embodiments, the method400further includes a step450of directing the source light beam125generated from a light source105to the PBS120. In some embodiments, the source light beam125is emitted from a light source105having at least one laser configured to emit one light in a first polarization state (e.g., one of vertically polarized light or horizontally polarized light).

Although some embodiments of the disclosure have been described in detail, those of ordinary skill in the art should understand that they could make various changes, substitutions and alterations herein without departing from the scope of the disclosure.