Light turning system, method for generating a turned field of illumination of polarized light and hybrid projector using the same

Abstract

A light turning system, a method for generating an illumination field of turned polarized light, a hybrid projector using the same and a method of generating an image using the hybrid projector are disclosed. The light turning system (60) comprises a plurality of optical elements, namely at least a light turning device (62), a polarization beam splitter (64), a polarization rotator (66) and one or more mirrors (68, 70, 72). The light turning device (62) is arranged for modulating and directing an incoming light beam (58) containing light in two orthogonal polarization states onto the polarization beam splitter (64). The polarization beam splitter (64) is arranged for receiving the modulated and directed light from the light turning device and splitting the light beam (58) into a transmitted light beam (58t) having a first polarization and a reflected light beam (58r) having a second polarization different from the first polarization. The polarization rotator (66) is arranged for rotating the polarization of one of the reflected light beam (58r) and the transmitted light beam (58t) to correspond to the polarization of the respective other light beam. The one or more mirrors (68, 70, 72) are arranged for reflecting and directing the transmitted light beam (58t) or the reflected light beam (58r) or both such that a) one of the light beams is reflected zero times and the other light beam is reflected an odd number of times, or b) one of the light beams is reflected an even number of times and the other light beam is reflected an odd number of times, and such that both light beams converge and meet in an image plane.

Description

Technical Field

[0001] This invention relates to a light steering system, a method for generating an illumination field of steered polarized light, and a hybrid projector using the same. The invention also relates to a method for generating an image using the hybrid projector. Background Technology

[0002] In recent years, light steering has become a very important technique for producing visually realistic images. Realistic images typically have high peak brightness and high dynamic range. Hybrid projectors, such as those shown in WO 2017 059537 A1, allow the production of visually realistic images by employing at least one base light engine and at least one specular engine for providing a registered illumination field at the entrance of an imaging engine that uses light distributed in the illumination field to produce an actual image on a screen.

[0003] In use, the base light engine and the highlight engine are connected to one or more light sources, which can be a common light source for both engines or separate light sources for each engine, and can produce white light or light of different colors. The base light engine produces a substantially uniform illumination field, while the highlight engine can produce an illumination field in which one or more different areas are much brighter than other areas, as needed. To this end, the highlight engine includes at least one light steering system, which typically includes multiple optical elements, such as, in particular, at least one light steering device, such as a phase light modulator, which can produce a directed beam, i.e., it allows light to be directed from the light source to one or more areas in the illumination field as needed. Compared to a single ray whose spatial extension is negligible, a beam, as used herein, has a specific spatial extension orthogonal to its propagation direction.

[0004] The illumination field of the redirected light can then be used by the imaging element to create a visually realistic image with very bright areas. Similarly, the light can be redirected away from certain areas of the illumination field, allowing for darker areas in the image. This allows for more efficient use of the overall light budget, achieving higher brightness peaks and lower black levels, resulting in higher contrast and a wider dynamic range. If a phase modulator is used as the light redirection device, it can phase-modulate the incident light, resulting in constructive interference in some areas and destructive interference in others.

[0005] Some hybrid projectors use separate base light engines and specular engines to generate illumination fields of different colors (typically red, green, and blue), which are then combined in a color engine. Other hybrid projectors generate illumination fields of different colors by using different colors in a time-sequential manner. In any case, the light from the base light engine (so-called base light) and the light from the specular engine (so-called specular) must be combined before entering the imaging engine.

[0006] A common method for combining the base beam and the highlight beam is polarization combining: the base beam and the highlight beam are orthogonally polarized relative to each other, for example, one is s-polarized and the other is p-polarized, and the two are combined by a polarization beam combiner, which is essentially a polarization beam splitter used in opposite directions.

[0007] While some optical steering devices work best with polarized light, others, particularly next-generation phase modulators based on microelectromechanical systems (MEMS) technology, operate with either polarized or unpolarized light. Some modulators used in high-power systems are hermetically sealed in glass, which, during use, becomes birefringent due to heating and the resulting mechanical stress. Therefore, even when polarized light is used as the source for generating highlights, the highlights may not be entirely polarized.

[0008] However, for some applications, such as combining the base light and highlight light, particularly via a polarized beam combiner, it is still preferable, or even necessary, to generate a polarized beam of the steering light, even when using unpolarized light as the source of the optical steering system. An obvious solution to this problem would be to use a polarizer on the steering beam (i.e., downstream of the optical steering device), but since the polarization state of the steering light is unpredictable in some cases, this would block at least some (or even most) of the steering light, resulting in lower system efficiency.

[0009] US 2004 / 0240057 A1 discloses a polarization restoration system for an LCD imager, wherein a beam of unpolarized light from a source is guided at a 45° angle to a polarization beamsplitter, which transmits a portion of the light having a first polarization and reflects another portion of the light having a second polarization orthogonal to the first polarization onto a waveplate. The waveplate rotates the polarization of the reflected beam to correspond to the polarization of the transmitted beam, and then guides the reflected beam parallel to the direction of the transmitted beam via a mirror.

[0010] While polarization restoration systems as shown in US 2004 / 0240057 A1 can be used in LCD imagers, they cannot be simply used in light-directing systems of the type described above because the two parallel beams will not illuminate the same entry area of ​​the imaging engine, thus reducing or even eliminating the desired effect. Furthermore, in the case of directed light, the optical path lengths of the two beams must be substantially the same because each beam produces an illumination field that can be considered an "image" at a certain distance, and after splitting the beams, it will be impossible to focus that image at two different distances.

[0011] In addition to the polarization restoration systems discussed above, other existing technical literature also covers various aspects of light steering and polarization processing in projection systems, but they also have limitations when applied to the type of light steering system described herein.

[0012] WO 2022 / 069727 A1 discloses a light steering system with a polarization beam splitter, a polarization rotator, and a reflector. While it describes splitting an unpolarized beam into two polarized beams, rotating the polarization of one beam, and then recombining them, it does not address the challenge of efficiently modulating light containing two orthogonal polarization states before the beam splitting occurs.

[0013] WO 2023 / 186324 A1 describes a hybrid projector system with a base light engine and a specular engine that uses light steering to generate an illumination field. While it discusses various optical arrangements for combining different color channels, it does not specifically address the efficient handling of unpolarized or mixed-polarized light during the light steering process.

[0014] US 2021 / 168340 A1 discloses a projection system having an optical steering device, a polarization beam splitter, and a polarization rotator. However, it uses separate light sources for different polarization states and does not describe a method for efficiently processing light containing two polarization states in a single optical path before beam splitting. Furthermore, the LCoS-based phase modulator in US 2021 / 168340 A1 typically modulates the phase of only one polarization direction, effectively acting as a mirror for orthogonal polarization directions, resulting in zero modulation or zero steering capability for that polarization. In contrast, our invention efficiently modulates and steering both polarization states simultaneously.

[0015] US 5,748,379A describes an optical system that uses polarization to separate and reassemble optical paths. While it discusses path length compensation, it does not address the challenges associated with modulating light containing two polarization states in an optical steering system.

[0016] US 2022 / 191440 A1 relates to projection systems and discusses various optical arrangements. However, it does not specifically address how to efficiently modulate and redirect light containing two orthogonal polarization states in a single optical path before polarization splitting.

[0017] While these existing technical documents address various aspects of light redirection and polarization processing, they do not fully solve the problem of efficiently modulating and redirecting light containing two orthogonal polarization states in a manner that maintains equal optical path lengths and ensures correct focusing of the resulting illumination field before polarization splitting occurs. Summary of the Invention

[0018] In view of the above limitations, the present invention aims to solve the problem of generating an irradiation field of redirected polarized light with high energy efficiency.

[0019] The problem is solved by the light steering system according to claim 1, the method for generating an illumination field of steered polarized light according to claim 23, the hybrid projector according to claim 18, and the method for generating an image according to claim 37. Advantageous embodiments are defined in the dependent claims.

[0020] The present invention ensures that there is essentially no loss of directional light when polarizing the beam of directional light, thereby allowing the generation and use of, for example, high-light illumination fields in a highly energy-efficient and therefore environmentally friendly manner.

[0021] This invention also promotes the use of unpolarized light as the source light for all light-directing devices that function well under such conditions, because in this case, polarized light is no longer needed to combine the directing light with the base light. By combining two types of orthogonally polarized beams with a polarized beam combiner, this invention facilitates doubling the amount of laser diodes of a specific wavelength used to illuminate the light-directing device without doubling the final beam size or final beam spread of the combined beam. Therefore, the power of the light-directing system can be significantly increased without increasing the minimum illumination point size. According to one embodiment, the light steering system includes multiple optical elements, namely at least a light steering device, a polarizing beam splitter, a polarizing rotator, and one or more mirrors. The light steering device is arranged to modulate an incident light beam and guide it onto the polarizing beam splitter, which is arranged to split the beam into a transmitted beam having a first polarization and a reflected beam having a second polarization different from the first polarization. The polarizing rotator is arranged to rotate the polarization of one of the reflected and transmitted beams to correspond to the polarization of the other beam. The one or more mirrors are arranged to reflect and guide one or both of the transmitted and reflected beams such that a) one beam is reflected zero times and the other beam is reflected an odd number of times, or b) one beam is reflected an even number of times and the other beam is reflected an odd number of times, and the two beams converge and meet in the image plane. This advantageously allows not only the use of substantially all steering light in the image plane but also ensures that the reflected and transmitted beams have the same orientation, i.e., they are not mirror images of each other. In other words: although by definition the reflected beam has already been reflected once, the total number of reflections experienced by each beam (including the first) must be a) odd or b) even, including zero (the transmitted beam may not be reflected at all, but this is not a preferred arrangement, as explained below). As used herein, the term "image plane" refers to the plane where converging beams meet. The image plane is a virtual plane through which the beams pass. Therefore, the term "converging" involves the fact that, looking down along the beam's propagation path, the beams are not parallel, but converge toward each other before they meet in the image plane. They may then diverge, however, this can be addressed with appropriate relay optics, as explained later. The image plane can also be the entry point for an image, allowing light to be used directly to generate an image.

[0022] Therefore, the illumination field of the polarized directional light generated in the image plane can be regarded as an intermediate image, especially a first intermediate image, because multiple intermediate images may be created depending on the further processing of the beam.

[0023] The light-directing device of this invention, particularly when implemented as a phase modulator, is capable of modulating two orthogonal polarization states of an incident beam indiscriminately. This means that the device applies the same phase modulation to the entire incident beam, regardless of the polarization states of its constituent light. As a result, when the modulated beam is subsequently split by a polarization beam splitter, both the transmitted and reflected beams undergo the same phase modulation. This characteristic ensures that the redirected light patterns formed by the two beams are substantially identical, which is crucial for maintaining the integrity and quality of the final illumination field.

[0024] In a preferred embodiment, the light steering device includes separate phase modulators for different colors, each modulator being arranged to indiscriminately modulate two orthogonal polarization states for its corresponding color. This configuration allows for efficient processing of multiple color channels while maintaining the ability to modulate two polarization states simultaneously for each color. By using separate modulators for different colors, the system can independently optimize steering and modulation for each wavelength, potentially improving overall color management and image quality. Furthermore, this arrangement allows for different steering distances for each color, which can be advantageous given that the optimal steering distance can vary with wavelength (as described in the formula of claim 10 (original claim 9)). This approach combines the benefits of color-specific optimization with the efficiency of processing two polarization states for each color in a single device, resulting in a versatile and high-performance light steering system.

[0025] Additionally or alternatively, the optical steering device can be a single device that modulates both polarization states indiscriminately. This offers several advantages. First, it allows for more compact and cost-effective system designs because only one modulation device is needed, rather than separate devices for each polarization state. Second, it simplifies the control and synchronization of the optical steering process because the same modulation mode can be applied to the entire incident beam. Finally, this approach ensures that any variations or defects in the modulation process affect both polarization states equally, thus helping to maintain consistency in the final illumination field. This polarization-agnostic modulation is particularly beneficial in systems using unpolarized or mixed-polarization light sources because it eliminates the need for pre-polarization of the incident light or separate processing of different polarization states. It also facilitates efficient use of the overall optical budget from the source, regardless of its polarization characteristics.

[0026] Alternatively or additionally, the light steering device can be a phase modulator based on microelectromechanical systems (MEMS). Such MEMS-based modulators are particularly well-suited for this application because they are able to modulate light regardless of its polarization state. The pixels or elements of these MEMS devices can be controlled to create the desired phase pattern across the entire incident beam, thereby affecting both orthogonal polarization states equally.

[0027] Additionally or alternatively, polarizing beam splitters and one or more mirrors can be arranged such that the reflected and transmitted beams each form an illumination field on the image plane, the illumination fields overlapping each other and being substantially identical in size and light distribution. These illumination fields are typically rectangular and may already have the same aspect ratio, or even, in some cases, the same size as the entrance in an imaging engine using the highlight. Typically, the illumination fields are re-imaged by relay optics that can optionally perform additional optical transformations on the two beams at the entrance of the combining element (also using the same minimum f-number) that combines the highlight and baseline beams, such as: telecentricating the beams; adding diffusers (one or more, static or dynamic) to reduce speckle while filling the available optical spread; and enlarging the beam size so that it has the same size as the beam at the light bar exit in the baseline path, which can be used as a averaging element in that baseline path. Preferably, the illumination field varies relatively slowly in space due to a "minimum size" characteristic called the point spread function, which occupies a significant portion of the illumination area, i.e., having a diameter of 5-20% of the size of the externally irradiated beam. This allows for some distortion differences between two beams with the same light distribution due to differences in the angle of incidence.

[0028] In these cases, the illumination field of the polarized redirecting light in the image plane will be the first intermediate image, and its image through the relay optics will be the second intermediate image.

[0029] Additionally or alternatively, polarizing beam splitters and one or more mirrors can be arranged to converge the transmitted and reflected beams toward the image plane, forming an angle of no more than 20°, preferably less than 15°, and more preferably less than 10° with each other. Since typical image engines accept incident beams with in-cone half-angles as high as 15° or more, this arrangement ensures that the combination of transmitted and reflected beams with two different angular fields of view is fully accepted by the optical system. Differences in the incident angles of the transmitted and reflected beams on the image plane can lead to different local optical distortions and local optical defocusing effects in two beams with the same steerable beam pattern. Those skilled in the art will understand that, with the convergence kept below 20°, more preferably 15°, and even more preferably 10°, these local variations between the two steerable beams will remain at least an order of magnitude lower than the overall range of the minimum optical steerable point size (also known as the point spread function, or PSF), so that these variations do not substantially alter the illumination distribution of the optical steerable system.

[0030] Additionally or alternatively, a polarizing beam splitter and one or more mirrors can be arranged to guide the reflected and transmitted beams onto the image plane from different directions at non-zero incident angles, the incident angles being substantially the same. With this arrangement, the local distortion (i.e., trapezoidal distortion) and local defocusing effects caused by the oblique incidence of each beam on the image plane are understood to become more symmetrical and balanced against each other (partially self-compensating), thereby reducing even more local variations in the redirected illumination profile.

[0031] Additionally or alternatively, the polarizing beam splitter and one or more mirrors can be arranged such that the optical paths of the reflected beam to the center point of the beam point in the image plane and the optical paths of the transmitted beam to the center point of the beam point in the image plane have substantially the same optical length. This advantageously ensures that the illumination fields from the reflected and transmitted beams can be focally aligned. To achieve this, the optical path of the reflected beam may include optical elements for compensating for focal offset of the transmitted beam, particularly at least one glass plate.

[0032] Additionally or alternatively, the polarization rotator may be one of a Faraday rotator, a prism rotator, and a birefringent rotator, particularly a quarter-wave plate or a half-wave plate. Therefore, those skilled in the art can advantageously select the rotator best suited for the respective use case.

[0033] Additionally or alternatively, the light steering device can be a phase light modulator, particularly a microelectromechanical device (MEMS). This type of light steering device has proven particularly useful when the corresponding light steering system is to be used in high-quality projectors, especially high dynamic range hybrid projectors for cinemas, etc.

[0034] If the optical steering device is a phase light modulator comprising multiple pixels and having a pixel pitch (i.e., the center-to-center distance between adjacent pixels (which may be micromirrors)), then the minimum optical path length d between the phase light modulator and the image plane is the length of any path that passes through the polarization beam splitter and along either the transmitted beam or the reflected beam. 最小 It can be advantageously set as d 最小 =img_size / tan(sin -1 (λ / pp), Where img_size is the maximum dimension of the illumination field to be formed in the image plane, λ is the wavelength of the incident beam, and pp is the pixel pitch.

[0035] Additionally or alternatively, the light steering system may include additional optical elements arranged in or after the image plane, such as elements for amplifying the illumination field formed in the image plane, and optionally also for recovering telecentricity by imaging the light steering device at infinity. In other words, using such optical elements, a relay optics can be formed that re-images the first intermediate image onto a second intermediate image so as to have, for example, the desired size for combination with the base light. The additional optical elements may also include one or more diffusers for speckle removal and laser safety purposes (as is done in most cases, where the light source is a laser). For example, a single diffuser may be used in the plane of the second intermediate image, or a combination of two diffusers may be used, one in or near the first intermediate image plane and one in the plane of the second intermediate image. Using at least two diffusers increases laser safety in case one of the diffusers is damaged.

[0036] Additionally or alternatively, the light steering system may include three separate arrangements, each including a light steering device, a polarizing beam splitter, and one or more mirrors arranged to deflect the light beam, each of the three separate arrangements being adapted to guide light of one of three different colors toward the image plane. In this embodiment, the light steering system may also include at least one light combining element arranged to combine light beams of different colors and guide them onto the image plane. Such at least one light combining element is a combination of a dichroic prism, a dichroic mirror, or a dichroic mirror. In another preferred embodiment, the light steering system includes a polarizing beam splitter and three separate light steering devices, each arranged with two dichroic mirrors, to guide light of three different colors along at least partially overlapping optical paths onto the polarizing beam splitter. In another optional preferred embodiment, the light steering system includes a light steering device, a polarizing beam splitter, and an optical path length compensation arrangement comprising one or more mirrors and dichroic mirrors, disposed between the light steering device and the polarizing beam splitter, to allow simultaneous deflection of light of at least two different wavelengths. Each of these embodiments allows the use of high-efficiency laser sources of different colors to generate an illumination field of steered polarized light as needed.

[0037] In one embodiment, the hybrid projector according to the invention includes a base light engine and a highlight engine. The base light engine is arranged to generate a first illumination field in an illumination plane, and the highlight engine is arranged to generate a second illumination field in the illumination plane that overlaps with the first illumination field. The highlight engine includes at least one light steering system as described above. This hybrid projector allows for the production of highly realistic images with a high dynamic range.

[0038] In a preferred embodiment, at least one light steering system of the hybrid projector is arranged such that the image plane lies within the illumination plane. This allows for a very compact design of the projector with very few optical components. However, in most cases, the image plane will be positioned upstream of the illumination plane.

[0039] Additionally or alternatively, the hybrid projector may include three separate arrangements, each including a base light engine and a highlight engine, each arranged to generate an overlap of a first illumination field and a second illumination field of one of three different colors, and further includes a light combining element arranged to combine the first illumination fields of the three separate arrangements.

[0040] A method for generating an illumination field of diverted polarized light according to one embodiment includes the following steps: -Guide the light beam to the light deflector. - Modulate the light beam using the light steering device to obtain a steered light beam, and guide the light onto the polarizing beam splitter. - The polarization beam splitter splits the light beam into a transmitted beam with a first polarization and a reflected beam with a second polarization different from the first polarization. - The polarization of one of the reflected beam and the transmitted beam is rotated to correspond to the polarization of the corresponding other beam. - Reflecting the transmitted beam and one or both of the reflected beams, such that a) One beam is reflected zero times, and the other beam is reflected an odd number of times, or b) One beam is reflected an even number of times, and the other beam is reflected an odd number of times, and The beams are guided so that the two beams converge in the image plane.

[0041] In a preferred embodiment, modulating the beam includes using separate phase modulators for different colors, each modulator being arranged to indiscriminately modulate two orthogonal polarization states for its corresponding color. This approach allows for precise control of each color channel while maintaining the efficiency of simultaneously processing two polarization states. By modulating each color separately, the method can adapt to specific requirements of different wavelengths, such as different steering distances or phase modulation modes. This can result in improved color fidelity and more accurate light steering across the entire visible spectrum. Furthermore, this approach maintains the advantage of efficient polarization processing for each color, potentially reducing light loss and improving overall system efficiency. This ability to independently optimize modulation for each color while still processing two polarization states allows for a more flexible and adaptive light steering process suitable for a wide range of high-performance projection and illumination applications.

[0042] Alternatively or additionally, the reflected beam and the transmitted beam may each form an illumination field on the image plane, the illumination fields overlapping each other and being substantially the same in size and light distribution.

[0043] In another preferred embodiment, the transmitted beam and the reflected beam converge toward the image plane, forming an angle of no more than 20°, preferably less than 15°, and more preferably less than 10° with each other.

[0044] Alternatively or additionally, the reflected beam and the transmitted beam may each be guided onto the image plane from different directions at non-zero illumination angles, wherein the illumination angles are substantially the same. Preferably, the different directions are coplanar with the normal to the image plane.

[0045] Alternatively or additionally, the reflected beam and the transmitted beam may be guided to the image plane such that their optical path lengths to the center point of the beam point in the image plane are substantially the same.

[0046] Additionally or alternatively, modulating the light beam may include, in particular, modulating the phase of the light rays forming the light beam using microelectromechanical devices.

[0047] Additionally or alternatively, the beam may be guided through optical elements arranged in or behind the image plane, such as elements for amplifying the illumination field formed in the image plane and optionally for restoring telecentricity by imaging the light steering device at infinity and / or one or more diffusers for speckle removal and laser safety purposes.

[0048] Additionally or alternatively, the method may include guiding three different colors of light toward the image plane via three separate arrangements comprising a light steering device, a polarizing beam splitter, and one or more mirrors arranged to deflect the light beam, each of the separate arrangements being suitable for one of the three different colors. The different colors of light beams may be combined via at least one combining element. Alternatively, the three different colors of light are guided onto the polarizing beam splitter along at least partially overlapping optical paths via three separate light steering devices, each for each of the three colors, and at least two dichroic mirrors. Alternatively, three different wavelengths of light are simultaneously guided toward the image plane via a light steering device, a polarizing beam splitter, and an optical path length compensation arrangement comprising one or more mirrors and a dichroic mirror, the one or more mirrors and the dichroic mirror being arranged between the light steering device and the polarizing beam splitter. Alternatively, the three different wavelengths of light are guided toward the image plane in a time-sequential manner via a light steering device and a polarizing beam splitter.

[0049] According to one embodiment, a method for generating an image includes generating a first illumination field in an illumination plane, and generating a second illumination field overlapping the first illumination field in the illumination plane, wherein one of the illumination fields is a base light illumination field, and the other is an illumination field of diverted polarized light generated as described above. This method can produce very realistic images with high dynamic range.

[0050] In a preferred embodiment, the base illumination field is temporarily modulated, for example, depending on the image content, to generate a uniform illumination field with dynamically varying intensity levels. If the image does not require many medium-brightness areas, highlight illumination can be fully utilized to generate highlights, thereby reducing baseline illumination. This results in darker black areas in the image and an increase in overall contrast in the image.

[0051] Further details and advantages of the invention will become apparent from the following exemplary and non-limiting detailed description, taken in conjunction with the accompanying drawings. Attached Figure Description

[0052] Figure 1 is a schematic diagram used to explain the basic principle of light steering.

[0053] Figure 2 This is a schematic diagram showing several components of the main components of a hybrid projector, including a light steering system.

[0054] Figure 3 This is a schematic perspective view illustrating the propagation of a light beam in a light steering system according to the first embodiment.

[0055] Figure 4 It shows the basis Figure 3 A schematic diagram of the optical path of a single ray in an optical steering system.

[0056] Figure 5 This is a schematic diagram showing the optical path of light in the light steering system according to the second embodiment.

[0057] Figure 6 This is a schematic diagram showing the optical path of light in the light steering system according to the third embodiment.

[0058] Figure 7 This is a schematic diagram showing the optical path of light in the light steering system according to the fourth embodiment. Detailed Implementation

[0059] An "imager" is any device operable to impart a desired image (which can be any pattern) to a beam of light. A spatial light modulator (SLM) can be used as an imager. For example, in a movie projector, an imager can be used to modulate light incident from one or more light sources according to image data in order to project an image onto a screen according to the image data.

[0060] "Engine" refers to a device for outputting light. An imaging engine includes at least one imager and has an inlet for at least one light source (such as a combination of light from a base light engine and a highlight engine).

[0061] A "light steering device" is a device used to generate a desired uniform or non-uniform light field at a certain distance by locally manipulating the main propagation direction of light when light is input.

[0062] A spatial light modulator (SLM) is a device that applies different changes to the properties of light at different locations. Typically, an SLM comprises an array of controllable elements or pixels that can be operated individually to alter the properties of light at their respective pixel locations. The properties of light that can be altered by an SLM include amplitude (light intensity), polarization, and phase. An SLM can modulate light transmitted through it (e.g., light incident on one surface of the SLM, and the modulated light emitted from the opposite surface).

[0063] A "spatial amplitude modulator" or "SAM" refers to a type of SLM that can be operated to controllably change the amplitude of light as it reaches a screen. Non-limiting examples of SAMs include liquid crystal panels (also known as LCDs), liquid crystal on silicon (LCoS) devices, and digital mirror devices ("DMDs"). DMDs have two operating states: an "on" state, in which light is sent to the projection lens and screen, and an "off" state, in which light is sent to a light collector. Amplitude modulation occurs through time modulation and rapid switching between the on and off states.

[0064] A “phase optical modulator” (PLM) (also known as a “spatial phase modulator” or “SPM”) is a type of SLM that can be operated to controllably change the phase of light. Non-limiting examples of PLMs are LCoS devices and MEMS devices that have already been mentioned.

[0065] Spatial amplitude modulators (PLMs) are typically made of an array of pixels that traditionally reflect or transmit an incident beam of light while independently modulating the amplitude of each pixel. Phase-modulated light modulators (PMMs) have a very similar structure, but instead of modulating the amplitude of the beam, they add a phase value at each pixel. Thus, a PLM can be viewed as a 2D pixelated programmable diffraction grating capable of producing non-uniform illumination patterns at a distance. Light can be distributed within the desired pattern, for example, to create localized highlights within the illumination field. PLM devices are typically reflective, but some transmissive configurations have been reported in the literature.

[0066] SLM can modulate light reflected from one surface of the SLM (e.g., light is incident on one surface of the SLM and the modulated light is emitted from the same surface of the SLM).

[0067] Some SLMs operate only to modulate optical amplitude. Some SLMs operate to modulate optical phase. Some SLMs operate to modulate both optical amplitude and optical phase. The operation of some SLMs can be dynamically controlled in real time to modulate only optical amplitude, only optical phase, or both optical phase and optical amplitude.

[0068] The "f-number" is a dimensionless number that can be used to characterize an optical system. The f-number is the ratio of the focal length of the optical system to the diameter of the entrance pupil of the optical system.

[0069] The term "highlight" refers to a projected light field (which can include an image) that represents a bright spot or area of ​​light. A highlight can include the brightest point in the light field.

[0070] As used herein, a "highlight beam" includes a beam capable of generating a non-uniform light field comprising one or more highlights at a target region. The target region can be, for example, a screen or image plane onto which the highlight beam is incident. Alternatively, the target of the highlight beam can be an imager (such as a SAM) that is subsequently illuminated by the highlight beam to provide a complete and highly refined image projected onto a screen. A highlight beam can include areas with higher illumination intensity and areas with lower illumination intensity. For example, a highlight beam can be generated by light redirection. Highlight beams can also be dynamic: the position and intensity of the highlights can change continuously along with the dynamic image (such as in a movie projector).

[0071] The term "modulation" refers to altering the properties of something. Light can be modulated in time and / or space. Examples of properties of light that can be modulated include amplitude (brightness or intensity), phase, and polarization state. Spatial modulation of light can be achieved by selectively modulating light at spatial locations (e.g., pixels) and / or by redirecting light. Light redirection involves diverting light that would otherwise illuminate some spatial locations to other spatial locations. For example, light redirection can be dynamically achieved using variable lenses, variable mirrors, and / or phase modulators (e.g., PLMs). The phase pattern applied by the PLM can guide incident light to selected areas in the image plane. Interference between different portions of the guided light can result in some locations in the image plane having more light (i.e., constructive interference) and / or some locations in the image plane having less light (e.g., destructive interference). As a result of this interference, the phase pattern applied by the PLM can effectively redirect or guide the incident light away from certain areas in the image plane, and / or redirect or guide the light to concentrate it in certain areas of the image plane.

[0072] The numerical aperture, or "NA," of an optical system is a dimensionless number that provides a measure of the range of angles through which incident light can pass through the optical system. NA is given by the product of the refractive index of the medium through which the incident light passes to reach the optical system and the sine of the maximum angle (also called half-angle) of the ray that will pass through the optical system relative to the optical axis of the optical system.

[0073] The "acceptance angle" of an optical system is a solid angle, which is the angle within which light rays entering the optical system will pass through it. The solid angle can be measured in steradian degrees.

[0074] "Spread" is a number that characterizes the degree to which light is "spread out" in terms of area and angle. From the perspective of an optical system, spread can be defined as the area of ​​the incident pupil of the optical system multiplied by the angle of reception of the optical system (as defined in this article).

[0075] In the accompanying drawings, similar or identical elements in different embodiments are given the same reference numerals, and repetitive descriptions of these elements are avoided as much as possible. To avoid overloading the drawings, not all elements are given reference numerals when explicitly shown. Furthermore, those skilled in the art will understand that, in addition to the elements shown in the drawings, reference numerals may also be used, for example in… Figures 3-7 Additional elements, such as a glass plate, are used in the optical path of the reflected and / or transmitted beam to compensate for the focal shift of the transmitted beam.

[0076] The term "light steering" refers to the operation of directing light toward a specific area, which is achieved through light steering devices such as phase light modulators. Figure 1 illustrates the general principle of light steering using a PLM 10 with a phase grating.

[0077] exist Figure 1A In the PLM 10, the phase grating is "off" at the following level: all pixels are set to the mode in which they add the same phase modulation to the incident light. Therefore, a "constant phase grating" is formed across the entire pixel array of the PLM 10, and the PLM is in a so-called "mirror mode".

[0078] exist Figure 1B In this process, the phase grating on the PLM 10 is "turned on" and controlled to cause its individual controllable elements to generate... Figure 1B The desired pattern is schematically indicated by concentric ellipses. The incident beam 12 is modulated by PLM 10 at this time, and the reflected beam is the redirecting beam 14.

[0079] Controlling light-directing devices like the PLM 10 itself is well known in the art and is done automatically using appropriate computing hardware based on the data of the desired image and the desired light distribution, respectively. Therefore, those skilled in the art will understand that devices and systems including projectors as disclosed herein always include such hardware and are connected in use to such hardware, including a corresponding power supply, but such elements are not shown in the accompanying drawings.

[0080] Figure 2This is a schematic diagram illustrating several of the main components of a hybrid projector 20. In this embodiment, the hybrid projector 20 includes an imaging engine 22 with three DMDs 24 for modulating three different colors of light and inputting that light into a projection element 26, which includes at least lenses for, for example, creating an image and projecting it onto, for example, a movie screen. In the schematic diagram, some light beams are represented by gray light beams.

[0081] In this embodiment, the imaging engine 22 includes a total internal reflection prism 28 (TIR prism for short) and a tri-color prism 30 (also known as a "Philips prism") for distributing three different colors of light onto the corresponding DMD 24.

[0082] The hybrid projector 20 also includes a base light engine 32 and a highlight engine 34, whose respective light is combined in a unit 36, which includes a polarizing beam combiner 38 and some relay optics 40.

[0083] In use, the base light engine 32 uses light from one or typically three light sources 46 (such as three different colors of lasers) to generate a typical rectangular base light illumination field of polarized light via some integrated optics 42, which is schematically represented by 44. Using the same or separate light sources 48, the highlight engine 34 generates a highlight illumination field of directed polarized light, which is also typically rectangular, and is schematically represented by 50. This illumination field can be regarded as a second intermediate image as explained above.

[0084] The polarization state of the light from the high-light engine 34 is orthogonal to the polarization state of the light from the base light engine 32, so that the light from the two engines can be combined using the polarization beam combiner 38. For this purpose, the light from the light source 48 is diverted via the light-directing engine 52 (particularly including the light-directing system according to the invention) to produce a first illumination field of diverted polarized light, schematically represented by 54. This illumination field can be considered as a first intermediate image, which is then processed by some relay optics 56 to produce an illumination field 50. By modulating the light source 48 (i.e., the red, green, and blue lasers forming "the" light source), the homogenized beam fluctuates over time depending on how much baseline light is required for the final content.

[0085] Illumination fields 44 and 50 are combined in unit 36 ​​and input into TIR prism 28, where incident light is reflected into tri-color prism 30. In the illustrated embodiment, tri-color prism 30 is configured to distribute red, green, and blue light onto corresponding DMDs 24, where the light is modulated and reflected back to tri-color prism 30, and then passes from tri-color prism 30 through TIR prism 28 into projection unit 26. In some embodiments, instead of using relay optics 56, illumination field 54 is combined with illumination field 44. In the illustrated embodiment, light sources 46 and 48 may each include separate lasers for outputting green, red, and blue light used in a time-sequential manner. However, in other embodiments, the hybrid projector may include an arrangement of three separate base light engines and highlight engines, each arranged to produce an overlap of a first and second illumination field of one of three different colors; these arrangements may be used simultaneously.

[0086] Figure 3 This is a schematic perspective view showing the propagation of an unpolarized light beam 58 in a light steering system 60 according to a first embodiment. Figure 4 It shows the basis Figure 3 A schematic diagram of the optical path of a single ray in an optical steering system. (Compared to...) Figure 4 similar, Figure 5 , Figure 6 as well as Figure 7 This is a schematic diagram showing the optical path of light in the light steering system according to the second, third and fourth embodiments.

[0087] Figure 3 as well as Figure 4 The optical steering system includes an optical steering device 62, a polarization beam splitter 64, a polarization rotator 66, and reflectors 68, 70, and 72.

[0088] A light steering device 62 is arranged to modulate the incident beam 58 and guide it to a polarization beam splitter 64, which splits the beam 58 into a transmitted beam 58t with a first polarization (e.g., p-polarization) and a reflected beam 58r with a second polarization (e.g., s-polarization) different from the first polarization (e.g., s-polarization).

[0089] A polarization rotator 66 is arranged to rotate the polarization of one of the reflected and transmitted beams to correspond to the polarization of the other beam. In the illustrated embodiment, the polarization rotator 66 is arranged in the path of the transmitted beam 58t. If beam 58t is p-polarized before entering the polarization rotator 66, it will become s-polarized after entering the polarization rotator 66. Therefore, beams 58r and 58t ultimately have the same polarization and can thus be, for example, via... Figure 2The polarization beam combiner shown in Figure 38 can be easily combined with other beams. In the illustrated embodiment, the polarization rotator 66 is a half-wave plate, but other polarization rotators such as Faraday rotators, prism rotators, or quarter-wave plates can certainly be used.

[0090] In the illustrated embodiment, two reflectors 68 and 70 are arranged in the path of the transmitted beam 58t, and one reflector is arranged in the path of the reflected beam 58r. Since the reflected beam 58r is reflected once by the polarizing beam splitter 64 and once by the reflector 72, the total number of reflections experienced by the reflected beam 58r (including the reflected beam at the beam splitter) is even, just like the number of reflections experienced by the transmitted beam 58t, and the images represented by the two beams are not mirror images of each other.

[0091] Polarizing beam splitter 64 and reflectors 68, 70 and 72 are arranged such that the reflected beam 58r and the transmitted beam 58t converge at an angle α. Figure 4 ), and converge in image plane 74. Each beam 58r and 58t forms an illumination field on image plane 74, the illumination fields overlapping each other and being substantially the same in size and light distribution, thereby producing a first illumination field of redirected polarized light, such as Figure 2 The first illumination field, indicated by 54, can be considered as a first intermediate image. Note the perspective view ( Figure 3 The quadrilateral and two-dimensional diagram used to indicate image plane 74 in ) Figure 4 The lines used to indicate the image plane 74 are virtual and do not indicate actual components, but components such as diffusers can be located there. The polarization beam splitter 64, polarization rotator 66, and reflectors 68, 70, and 72 form a polarization restoration unit (PRU) 76, except... Figure 3 as well as Figure 4 In addition to the light steering system 60 shown, the polarization restoration unit (PRU) 76 can also be used in many different light steering systems and configurations (such as...). Figure 5 , Figure 6 as well as Figure 7 The configuration shown.

[0092] like Figure 4As shown, the reflected beam 58r and the transmitted beam 58t are each guided onto the image plane 74 from different directions at a non-zero illumination angle of approximately α / 2, the illumination angles being substantially the same and coplanar with the normal to the image plane 74. The polarizing beam splitter 64 and the mirrors 68, 70, and 72 are arranged such that the angle α at which the transmitted beam 58t and the reflected beam 58r converge toward the image plane 74 does not exceed 20°, preferably less than 15°, and more preferably less than 10°. Furthermore, the polarizing beam splitter 64 and the mirrors 68, 70, and 72 are arranged such that the optical path length from the reflected beam 58r to the center point of the light spot in the image plane 74 is substantially the same as the optical path length from the transmitted beam 58t to the center point of the light spot in the image plane 74. This will be explained in more detail below. To achieve this, the optical path of the reflected beam 58r may include optical elements, particularly at least one glass plate (not shown).

[0093] As previously stated, the optical path lengths (hereinafter referred to as OPL) of the reflected beam 58r and the transmitted beam 58t are essentially equal. Generally, some conditions in this regard should be met. If: L1 represents the OPL from the optical steering device 62 to the polarization beam splitter 64. L2 represents the OPL of the reflected beam 58r from polarizing beam splitter 64 to reflector 72. L3 represents the OPL of the reflected beam 58r from the reflector 72 to the first intermediate image plane 74. L4 represents the OPL of the transmitted beam 58t from polarizing beam splitter 64 to reflector 68. L5 represents the OPL of the transmitted beam 58t from mirror 68 to mirror 70. L6 represents the OPL of the transmitted beam 58t from the reflector 70 to the first intermediate image plane 74. L7 represents the OPL of the focal shift of the transmitted beam 58t introduced by the polarization beam splitter 64 in the transmitted beam 58t, and L8 represents the OPL of the focal shift of the transmitted beam 58t introduced by the polarization rotator 66. L1 + L2 + L3 = SD, where SD represents the turning distance, and L1 + L4 + L5 + L6 = SD + L7 + L8. The small asymmetry between the paths of the transmitted beam 58t and the reflected beam 58r is compensated for in the path of the reflected beam by one or more glass plates. The precise values ​​of L4 and L5 can be easily determined using known optical optimization algorithms.

[0094] OPL L3 and L6 should be long enough to completely separate the two beams 58r and 58t.

[0095] When the light steering device 62 is a PLM (Plastic Ray Module), the steering distance SD should not be shorter than the minimum distance required to completely separate the different diffraction orders of the steering light generated by the periodic structure of the PLM at the image plane 74. However, technically, a shorter distance than this minimum distance can be chosen, but in that case, orders other than the "master" diffraction order with a large light intensity will still fall in the target area (because they have not been sufficiently separated at a short distance), thus producing "ghosting" highlights at undesired locations in the (active) image area.

[0096] The smaller the separation angle α, the longer the optical path lengths L3 and L6 need to be. The separation angle α is preferably kept as small as possible. Since beams 58r and 58t each arrive at the first intermediate image plane 74 at an angle approximately equal to α / 2, the images are correspondingly tilted and therefore may be slightly out of focus and slightly distorted (they will appear slightly trapezoidal). Since these image defects in one image are opposite to those in the other, the two images cannot be perfectly matched, but it would be better if α were kept small.

[0097] OPL L1 should be large enough to avoid interference between polarizing beam splitter 64 and the incident beam (i.e., the unpolarized beam from optical steering device 62). As those skilled in the art will understand, other configurations are possible, for example, by providing additional folding mirrors in each optical path.

[0098] The light steering system 60 can be used in hybrid projectors, for example, according to Figure 2 In hybrid projectors, light redirection is performed in a time-sequential manner, particularly in the case of red, blue, and green light.

[0099] Figure 5 A light steering system 80 is shown, comprising three PRUs 76, 76', 76" for simultaneously steering three different colors of light (typically a red beam 58, a green beam 58', and a blue beam 58) toward the same intermediate image plane 74. For this purpose, separate light steering devices 62, 62', 62" are used for each incident beam 58, 58', 58" of different colors, and two dichroic mirrors 82 and 84 are employed to align the corresponding optical paths of the polarized, steered reflected and transmitted beams toward the image plane 74.

[0100] The turning distances of different colored light beams (58", 58', and 58") are determined according to their corresponding wavelengths. Red, blue, and green light are commonly used, with blue light having the longest turning distance and red light the shortest.

[0101] Figure 6An embodiment of a light steering system 90 is shown, in which a PRU 76 is used in conjunction with three separate light steering devices 62, 62', and 62" (arranged with a reflector 92 and two dichroic reflectors 94 and 96) to deflect three different colored light beams 58, 58', and 58" along the same path in the PRU 76 to reach the image plane 74. Typically, beam 58 will be red light, beam 58' will be green light, and beam 58" will be blue light. Similarly, the deflection distance increases sequentially from red light to green light to blue light. Reflector 92 is a standard reflector, while reflectors 94 and 96 are dichroic reflectors (reflector 94) that reflect green light and transmit red light, and dichroic reflectors (reflector 96) that reflect blue light and transmit red and green light, respectively.

[0102] Figure 7 An embodiment of a light redirection system 100 is shown, which includes a PRU 76, a single light redirection device 62, and four dichroic mirrors 102, 104, 106, and 108, as well as two standard mirrors 110 and 112 for optical path compensation. This arrangement allows for a very compact light redirection system. Similarly, the redirection path length increases inversely with the wavelength of the corresponding incident light on the light redirection device 62. If red, green, and blue light are conventionally used to create an image, mirrors 102 and 106 will reflect green and blue light, but allow red light to pass through. Mirrors 104 and 108 will reflect green light and allow blue light to pass through; mirrors 110 and 112 are standard mirrors.

[0103] To configure an optical assembly located in the optical path of at least one unpolarized beam to provide a fundamentally polarized beam to an intermediate image plane via optical deflection, deflecting the unpolarized beam into a first polarized beam and a second polarized beam, the optical assembly includes an optical deflector, a polarization beam splitter, a polarization rotator, and multiple mirrors. A method can be used that includes: determining the number of mirrors for reflecting the first and second polarized beams based on the number of reflections of the first and second polarized beams; determining the optical path lengths of the optical deflector, polarization beam splitter, polarization rotator, and multiple mirrors; calculating the placement angles of the optical deflector, polarization beam splitter, polarization rotator, and multiple mirrors; and optimizing the position and angle of the multiple mirrors in the optical path of the second polarized beam using an optical optimization algorithm. This method can take into account the thickness of the polarization-dependent deflection element and the thickness of the polarization rotator.

[0104] The aforementioned light steering system facilitates a method for generating an illumination field of steered polarized light, the method comprising the steps of: guiding a light beam to a light steering device; modulating the light beam with the light steering device to obtain a steered light beam; guiding the beam to a polarization beam splitter; splitting the beam into a transmitted beam having a first polarization and a reflected beam having a second polarization different from the first polarization; rotating the polarization of one of the reflected and transmitted beams to correspond to the polarization of the corresponding other beam; reflecting one or both of the transmitted and reflected beams such that a) one beam is reflected zero times and the other beam is reflected an odd number of times, b) one beam is reflected an even number of times and the other beam is reflected an odd number of times; and guiding the beams such that the two beams converge in an image plane. This method further facilitates image generation and includes generating a first illumination field in an illumination plane and generating a second illumination field in the illumination plane that overlaps with the first illumination field, wherein one of the illumination fields is a basic light illumination field and the other is an illumination field of steered polarized light generated by the method.

[0105] Within the scope of the invention as defined in the claims, numerous modifications can be made to the above examples, such as the number and arrangement of additional optical elements in the optical steering system (e.g., elements for compensating for any focal shift that a beam projected through an element like a polarization beam splitter or polarization rotator may experience).

[0106] List of reference numerals 10 Spatial Light Modulator (SLM) 12 incident beams 14-beam steering 20 Mixed Projectors 22 Imaging Engine 24-Digital Mirror Device (DMD) 26 projection components 28 Total Internal Reflection (TIR) 30 tri-color prism 32 Basic Light Engine 34 High-Gloss Engine 36 units for combining base light and highlight light 38-polarization beam combiner 40 Relay Optical Components 42 Integrated Optical Devices 44 Basic Light Illumination Field 46 light sources 48 light sources 50 High-light illumination field 52 Light Steering System 54 First Irradiation Field 56 Relay Optical Devices 58, 58', 58” beams 58r reflected beam 58t transmitted beam 60 Light Steering System 62, 62', 62” light steering device 64-polarization beam splitter 66 polarization rotator 68 Reflective Mirror 70 Reflective Mirror 72 Reflector 76, 76', 76” polarization restoration unit (PRU) 74 Image Plane 80 Light Steering System 82 Dichroic Reflector 84 Dichroic Mirror 90 Light Steering System 92 Reflector 94 Dichroic Reflector 96 Dichroic Reflector 100 Light Steering System 102 Dichroic Reflector 104 dichroic reflector 106 Dichroic Mirror 108 dichroic reflector 110 rearview mirror 112 Reflective Mirror

Claims

1. A light steering system comprising a plurality of optical elements, i.e., at least including Light steering device, Polarizing beam splitter, Polarization rotator, and One or more mirrors, The light steering device is arranged to modulate an incident beam containing light in two orthogonal polarization states and guide it onto the polarization beam splitter. The polarization beam splitter, which receives modulated and guided light from the light steering device, is arranged to split the beam into a transmitted beam with a first polarization and a reflected beam with a second polarization different from the first polarization. The polarization rotator is arranged to rotate the polarization of one of the reflected beam and the transmitted beam to correspond to the polarization of the other beam. The one or more reflectors are arranged to reflect and guide one or both of the transmitted and reflected beams, such that... a) One beam is reflected zero times, and the other beam is reflected an odd number of times, or b) One beam is reflected an even number of times, and the other beam is reflected an odd number of times, and This causes the two beams to converge and meet in the image plane.

2. The light steering system according to claim 1, wherein, The light steering device includes separate phase modulators for different colors, each phase modulator being arranged to modulate two orthogonal polarization states indiscriminately for its corresponding color.

3. The light steering system according to claim 1 or 2, wherein, The optical steering device is a single optical steering device that modulates two orthogonal polarization states indiscriminately.

4. The light steering system according to any one of claims 1 to 3, wherein, The polarizing beam splitter and the one or more reflectors are arranged such that the reflected beam and the transmitted beam each form an illumination field on the image plane, the illumination fields overlapping each other and being substantially the same in size and light distribution.

5. The light steering system according to any one of claims 1 to 4, wherein, The polarizing beam splitter and the one or more mirrors are arranged such that the transmitted beam and the reflected beam converge toward the image plane, thereby forming an angle of no more than 20°, preferably less than 15°, and more preferably less than 10° with each other.

6. The light steering system according to any one of claims 1 to 5, wherein, The polarizing beam splitter and the one or more reflectors are arranged to guide the transmitted beam and the reflected beam onto the image plane from different directions at a non-zero illumination angle, wherein the illumination angles are substantially the same, and the different directions are preferably coplanar with the normal to the image plane.

7. The light steering system according to any one of claims 1 to 6, wherein, The polarizing beam splitter and the one or more reflectors are arranged such that the optical path length of the reflected beam to the center point of the beam point in the image plane and the optical path length of the transmitted beam to the center point of the beam point in the image plane are substantially the same.

8. The light steering system according to claim 7, wherein, The optical path of the reflected beam includes an optical element for compensating for the focal shift of the transmitted beam, in particular at least one glass plate.

9. The light steering system according to any one of claims 1 to 8, wherein, The polarization rotator is a Faraday rotator, a prism rotator, or a birefringent rotator, particularly a quarter-wave plate or a half-wave plate.

10. The light steering system according to any one of claims 1 to 9, wherein, The optical steering device is a phase optical modulator, and more particularly a microelectromechanical device (MEMS).

11. The light steering system according to claim 10, wherein, The phase light modulator includes multiple pixels with a pixel pitch, wherein the minimum optical path length d between the phase light modulator and the image plane, passing through the polarization beam splitter and along any path of the transmitted beam and the reflected beam. 最小 for d 最小 =img_size / time(sin -1 (λ / pp), Where img_size is the maximum dimension of the illumination field to be formed in the image plane, λ is the wavelength of the incident light, and pp is the pixel pitch.

12. The light steering system according to any one of claims 1 to 11, further comprising optical elements disposed in or after the image plane, such as, in particular, optical elements for amplifying the illumination field formed in the image plane and / or optical elements for restoring telecentricity and / or one or more diffusers for speckle removal and laser safety purposes.

13. The light steering system according to any one of claims 1 to 12, comprising three separate arrangements, each including a light steering device, a polarizing beam splitter, and one or more reflectors arranged for steering the light beam, each of the three separate arrangements being adapted to guide light of one of three different colors toward the image plane.

14. The light steering system of claim 13, further comprising at least one light combining element arranged to combine light beams of different colors and guide them onto the image plane.

15. The light steering system device according to claim 14, wherein, The at least one optical combination element is a dichroic prism, a dichroic mirror, or a combination of dichroic mirrors.

16. The light steering system according to any one of claims 1 to 12, comprising a polarizing beam splitter and three separate light steering devices, the three separate light steering devices being arranged with two dichroic mirrors to guide three different colors of light along at least partially overlapping optical paths onto the polarizing beam splitter.

17. The optical steering system according to any one of claims 1 to 12, comprising an optical steering device, a polarizing beam splitter, and an optical path length compensation arrangement comprising one or more reflectors and a dichroic reflector, disposed between the optical steering device and the polarizing beam splitter to allow for the simultaneous steering of at least two different wavelengths of light.

18. A hybrid projector comprising a base light engine and a highlight engine, the base light engine being arranged to generate a first illumination field in an illumination plane, the highlight engine being arranged to generate a second illumination field in the illumination plane that overlaps with the first illumination field, wherein the highlight engine comprises at least one light steering system according to claim 1.

19. The hybrid projector according to claim 18, wherein, The at least one light steering system is arranged such that the image plane is in the illumination plane.

20. The hybrid projector according to claim 18, wherein, The at least one light steering system is arranged such that the image plane seen along the light path is in front of the illumination plane.

21. The hybrid projector according to claim 18, wherein, The at least one light steering system is also configured according to any one of claims 2 to 17.

22. The hybrid projector according to any one of claims 18 to 21, comprising three separate arrangements including a base light engine and a highlight engine, each of the arrangements being arranged to generate an overlap of a first illumination field and a second illumination field of one of three different colors, and further comprising a light combining element arranged to combine the first illumination field and the first illumination field of the three separate arrangements.

23. A method for generating an illumination field of redirected polarized light, comprising the steps of: -Guide the light beam containing light in two orthogonal polarization states to the light deflector. - Modulate the light beam using the light steering device to obtain a steered light beam, and guide the light onto the polarizing beam splitter. - Receive modulated and guided light from the optical steering device at the polarization beam splitter. - The polarization beam splitter splits the light beam into a transmitted beam with a first polarization and a reflected beam with a second polarization different from the first polarization. - The polarization of one of the reflected beam and the transmitted beam is rotated to correspond to the polarization of the corresponding other beam. -Reflecting the transmitted beam and one or both of the reflected beams, such that a) One beam is reflected zero times, and the other beam is reflected an odd number of times, or b) One beam is reflected an even number of times, and the other beam is reflected an odd number of times, and -Guide the light beams so that the two beams meet in the image plane.

24. The method according to claim 23, wherein, Modulating the beam involves using separate phase modulators for different colors, each modulator being arranged to modulate two orthogonal polarization states indiscriminately for its corresponding color.

25. The method according to claim 23 or 24, wherein, The optical steering device is a single optical steering device that modulates two orthogonal polarization states indiscriminately.

26. The method according to any one of claims 23 to 25, wherein, The reflected beam and the transmitted beam each form an illumination field on the image plane, the illumination fields overlapping each other and being substantially the same in size and light distribution.

27. The method according to any one of claims 23 to 26, wherein, The reflected beam and the transmitted beam converge toward the image plane, forming an angle of no more than 20°, preferably less than 15°, and more preferably less than 10°.

28. The method according to any one of claims 23 to 27, wherein, The reflected beam and the transmitted beam are each guided onto the image plane from different directions at a non-zero illumination angle. The illumination angles are substantially the same, and the different directions are preferably coplanar with the normal to the image plane.

29. The method according to any one of claims 23 to 28, wherein, The reflected beam and the transmitted beam are guided to the image plane such that the optical path lengths of their optical paths to the center point of the beam point in the image plane are substantially the same.

30. The method according to any one of claims 23 to 29, wherein, Modulating the light beam includes, in particular, modulating the phase of the light rays that form the light beam by using microelectromechanical devices.

31. The method according to any one of claims 23 to 30, further comprising guiding the beam through optical elements arranged in or behind the image plane, such as, in particular, optical elements for amplifying the illumination field formed in the image plane and / or optical elements for restoring telecentricity and / or one or more diffusers for speckle removal and laser safety purposes.

32. The method according to any one of claims 23 to 31, comprising guiding light of three different colors toward the image plane via three separate arrangements comprising a light deflection device, a polarizing beam splitter, and one or more mirrors arranged to deflect the light beam, each of the separate arrangements being adapted to one of the three different colors.

33. The method of claim 32, further comprising combining light beams of different colors via at least one combining element.

34. The method according to any one of claims 23 to 33, comprising guiding light of three different colors along at least partially overlapping optical paths onto the polarizing beam splitter via three separate light steering devices, each for one of the three colors, and at least two dichroic mirrors.

35. The method according to any one of claims 23 to 34, comprising guiding light of at least two different wavelengths simultaneously toward the image plane via a light steering device, a polarizing beam splitter, and an optical path length compensation arrangement comprising one or more reflectors and dichroic reflectors, wherein the optical path length compensation arrangement is disposed between the light steering device and the polarizing beam splitter.

36. The method according to any one of claims 23 to 34, comprising guiding three different wavelengths of light toward the image plane in a time-sequential manner via a light steering device and a polarizing beam splitter.

37. A method for generating an image, comprising: A first irradiation field is generated in the irradiation plane. A second irradiation field is generated in the irradiation plane that overlaps with the first irradiation field. One of the irradiation fields is a basic light irradiation field, and the other is an irradiation field of diverted polarized light generated by the method according to any one of claims 23 to 36.

38. The method of claim 37 further comprises temporarily modulating the base light field to generate a uniform illumination field.

Images