Illumination light source and projection system

Abstract

This application provides a lighting source and a projection system. The lighting source includes a color light conversion element, an optical control element, and a light guiding module. The color light conversion element includes color partitions; the optical control element is disposed in the front optical path of the color light conversion element and includes multiple control partitions, each control partition having a corresponding color partition; the light guiding module is used to guide an initial light beam to the optical control element and guide at least a portion of the emitted light beams from the control partitions to their corresponding color partitions; when a color partition emits a light beam, the control partition corresponding to that color partition is in an open state; when a color partition does not emit a light beam, the control partition corresponding to that color partition is in a closed state; by controlling the states of multiple control partitions in a timing sequence, spatially separated temporally sequenced colored light beams can be formed on the emission side of the color light conversion element. This technical solution can improve the cost, size, and stability problems of traditional mechanical methods.

Description

Technical Field

[0001] This application belongs to the field of lighting and display technology, and more specifically, relates to a lighting source and a projection system. Background Technology

[0002] With the development of technology, projection system technology has become increasingly mature. A projection system is an optical system that illuminates an object and projects an image onto a projection screen. Due to its large projection area and immersive interactive experience, it is increasingly favored by users.

[0003] In single-panel projection systems, such as single DLP, single LCD, or LCoS systems, a combination of light-emitting elements and color wheels is commonly used as the illumination source. Whether it's a white light-emitting element with a filter wheel or an excitation light-emitting element with a phosphor wheel, the light emitted by the light-emitting element, after being processed by the color wheel, forms sequentially colored illumination light. This illumination light is incident on a spatial light modulator, where it is modulated at different times to form different colors of image light. This image light is then projected onto a predetermined projection surface by the projection lens. The different colors of image light are sequentially superimposed to form the final displayed image.

[0004] However, since the color wheel is a mechanical component, it suffers from stability issues during operation, which in turn leads to overall system instability. Furthermore, the color wheel requires a power source and a matching control chip, increasing the system's power consumption. Summary of the Invention

[0005] The purpose of this application includes, for example, providing a lighting source and projection system to improve or at least partially improve the problems of the prior art described above.

[0006] The embodiments of this application can be implemented as follows:

[0007] In a first aspect, a lighting source is provided, including a color conversion element, an optical control element, and a light guiding module. The color conversion element includes at least two color zones. The optical control element is disposed in the front optical path of the color conversion element, and the optical control element includes multiple control zones, each of which corresponds to a color zone. The light guiding module is used to guide an initial light beam to the optical control element and guide at least a portion of the emitted light beam from the control zone to its corresponding color zone. When a color zone emits a light beam, the control zone corresponding to that color zone is defined as being in an open state; when a color zone does not emit a light beam, the control zone corresponding to that color zone is defined as being in a closed state. By controlling the states of the multiple control zones of the optical control element in a timing sequence, spatially separated temporally colored light beams can be formed on the emission side of the color conversion element.

[0008] The color conversion element in this lighting source includes at least two color zones. An optical control element is disposed at the front end of the optical path of the color conversion element. The optical control element includes multiple control zones, and for each control zone, there is a corresponding color zone. A light guiding module guides the initial beam emitted from the lighting source to the optical control element on one hand, and guides at least a portion of the emitted beams from each control zone to its corresponding color zone on the other. By adjusting the control zone to be in an on or off state, the emission of a beam from the corresponding color zone is controlled, thereby forming spatially separated temporally colored light on the emission side of the color conversion element. The temporally colored light formed by this lighting source can be incident on downstream optical components (e.g., a spatial light modulator), and then modulated at different times to form image light of different colors. The image light of different colors is temporally superimposed to form the final display image. This lighting source can replace traditional lighting sources that combine light-emitting elements and color wheels. It doesn't adhere to the requirement that the light paths of different colors of light in a sequential color sequence completely overlap. Instead, by keeping the color conversion element stationary and controlling the on / off states of different control zones, it allows different color zones of the color conversion element to emit light at different times. This spatial separation of light distribution eliminates the need for mechanical rotating components, improving the stability and noise issues that occur with color wheels during operation. Furthermore, the control zones within this optical control element, each corresponding to a color zone, are independent. Different control zones are controlled independently, with one control zone not depending on the state of another. This makes operation simple and flexible, allowing for free adjustment of the emission time ratio of each color light to achieve multiple light emission modes. In contrast, once a color wheel is manufactured, the angle ratio of each color is fixed, cannot be adjusted, and it's impossible to emit two colors simultaneously.

[0009] Furthermore, the optical control element includes an optical phase control element, which includes a liquid crystal layer and multiple independent control zone driving circuits. Each control zone driving circuit corresponds to a control zone, and controls the electric field of the liquid crystal layer of the corresponding control zone, thereby controlling the exit phase of the initial beam incident on the control zone. Alternatively, the optical control element includes a micro-opto-electro-mechanical system (MEMS) element, which includes a micromirror array and multiple independent control zone driving circuits. Each control zone driving circuit corresponds to a control zone, and controls the electrode voltage of the micromirror array of the corresponding control zone, thereby controlling the exit angle of the initial beam incident on the control zone.

[0010] This technical solution can directly use mature devices such as LCD, LCoS, and DMD, or derivative technologies based on these mature technologies. It can be easily controlled by directly providing image signals, which is conducive to rapid product introduction. It eliminates the need for complex and time-consuming development of entirely new devices, thus reducing development costs.

[0011] Furthermore, each control zone includes multiple control sub-zones connected in series with each other. Under the control of the control zone drive circuit, the state changes of each control sub-zone within the same control zone are consistent.

[0012] This technical solution represents a significant improvement over traditional, complex LCD, LCoS, and DMD technologies. Instead of controlling devices at the pixel level, it connects large areas of "original pixels" in series, simultaneously changing their on / off states. This simplifies the device structure, eliminating the need for multiple circuit layers in optical control component manufacturing, thus reducing design and production costs and minimizing reliability degradation caused by device complexity. Furthermore, the elimination of pixel-level drive signals reduces bandwidth requirements, improving signal processing speed. For example, a traditional LCoS chip might have 1920×1080 pixels; this solution, by connecting large areas of pixels in series, achieves only 1×3 control zones, reducing the number of pixel memories by two million.

[0013] The optical control element includes an optical phase control element, which controls the exit phase of the initial beam incident on the control zone. Alternatively, the optical control element includes a micro-opto-electro-mechanical system (MEMS) element, which controls the exit angle of the initial beam incident on the control zone. These two methods respectively control the exit phase or the exit angle of the initial beam incident on the control zone.

[0014] In one implementation, at least two of the control partitions correspond to the same color partition.

[0015] This technical solution allows the brightness of the light emitted from a color zone to be adjusted by controlling the on / off state of different control zones corresponding to the same color zone, adding a modulation dimension and facilitating finer modulation.

[0016] Furthermore, it also includes a light-emitting element, which is disposed in the front optical path of the optical control element. The initial light beam emitted by the light-emitting element is guided by the light guiding module to cover all control zones of the optical control element. The light-emitting element emits white light, and the color conversion element is a filter element with at least two color zones; or, the light-emitting element emits excitation light, and the color conversion element is a fluorescent plate with at least two fluorescent regions or a fluorescent plate with at least one fluorescent region and one scattering region.

[0017] The light-emitting element of this lighting source can be a combination of white light and a filter element, or a combination of excitation light and a fluorescent plate, to achieve the replacement of the color wheel.

[0018] Furthermore, it also includes a light recovery device, which is disposed in the optical path between the light-emitting element and the optical control element. The light recovery device is used to recover at least a portion of the light beam emitted by the optical control element that did not enter the color light conversion element, and then re-homogenize and emit it back to the optical control element.

[0019] By setting up a light recovery device between the light-emitting element and the optical control element, unused illumination beams can be recovered, and the recovered beams can be re-homogenized and emitted into the optical control element, which helps to improve light utilization.

[0020] Furthermore, it also includes a relay optical element, which is disposed in the optical path at the rear end of the color light conversion element. The relay optical element is used to achieve the overlapping of the beams emitted from different color zones of the color light conversion element at a preset spatial position to obtain a spatially overlapping temporally colored beam.

[0021] Unlike the spatial overlap of the sequential color beams emitted from the color wheel, the sequential color beams emitted from the color conversion element are spatially separated because the color conversion element is fixed and stationary. By setting a relay optical element in the optical path at the rear end of the color conversion element, the beams emitted from different color zones of the color conversion element can overlap at a preset spatial position after passing through the relay optical element. This transforms the spatially separated sequential color beams into spatially overlapping sequential color beams at the predetermined preset spatial position, making it more convenient to apply to traditional sequential color beam application scenarios, such as lighting and image display.

[0022] Secondly, a projection system is provided, including a spatial light modulator and an illumination source. The spatial light modulator is located in the optical path behind the illumination source. The spatial light modulator is used to receive the time-sequential color beam emitted from the illumination source and modulate it according to image data before emitting image light. Each image frame includes multiple color subframes.

[0023] A projection system is formed by placing a spatial light modulator in the optical path at the rear end of the illumination source. The illumination flux incident on the spatial light modulator in the rear optical path can be adjusted by controlling the on and off states of the optical control elements. Color image modulation can be achieved by adjusting the spatial light modulator, which is beneficial for obtaining the projected display of color images.

[0024] Furthermore, during a color subframe, the time ratio of the on and off states of the control partition in the optical control element corresponding to the color subframe is controlled to adjust the luminous flux of the beam emitted to the spatial light modulator.

[0025] During a color subframe, the light flux emitted to the spatial light modulator is adjusted by controlling the time ratio of the on state and the light state of the control partition corresponding to that color subframe, which is convenient to adjust.

[0026] Furthermore, during an image frame, the time proportion of different color subframes is controlled by controlling the time proportion of different control partitions being in the open state based on the image data.

[0027] By dynamically adjusting the proportions of each color subframe using image data, light utilization and color brightness can be improved. Colors can be adjusted according to different images; for example, for a red image, the duty cycle of the red sequence can be increased (i.e., the on-state time of the corresponding control partition can be increased), while the duty cycles of the blue and green sequences can be decreased accordingly. This offers greater flexibility compared to a color wheel.

[0028] Furthermore, when the control zone in the optical control element switches between an open state and a closed state, the initial beam emitted to the control zone is shut off.

[0029] When the control zone of the optical control element is in the switching state area, the initial beam emitted to the control zone is turned off, which can effectively prevent color crosstalk or light leakage and help reduce image jitter.

[0030] Furthermore, during a color subframe, at least two control partitions are simultaneously turned on, and the two control partitions correspond to different color partitions.

[0031] This technical solution adds a color mixing sequence, which can improve the overall brightness of the projection system. For example, when the red and green zones are activated simultaneously, it is equivalent to adding a yellow zone; when all zones are activated simultaneously, it is equivalent to adding a white zone. This technical solution allows for the addition of red-green-blue-yellow or red-green-blue-white "high-brightness modes" in addition to the traditional red-green-blue "color modes," enriching the controllability of the projection system. Moreover, by directly controlling the addition of color mixing zones electronically, there is no need to add a separate yellow or white segment as with traditional color wheels. Therefore, when using only the red-green-blue segment in the "color mode," CLO (Color Light Output) can be achieved at 100%. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the structure of the lighting source provided in the embodiments of this application;

[0034] Figure 2 This is a schematic diagram of the projection system provided in an embodiment of this application;

[0035] Figure 3 This is a schematic diagram of a projection system structure provided in Embodiment 1 of this application;

[0036] Figure 4 This is a schematic diagram of a projection system structure provided in Embodiment 2 of this application;

[0037] Figure 5 Waveform diagram for switching and light source synchronization modulation of LCoS;

[0038] Figure 6 Waveform diagram of MOEMS's switching and light source synchronization modulation. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0040] It should be noted that, where there is no conflict, the features in the embodiments of this application can be combined with each other.

[0041] In existing technologies, projection systems, such as single DLP or single LCD / LCoS systems, commonly employ a projection structure that combines light-emitting elements and a color wheel.

[0042] Because the color wheel is a mechanical component, it requires a matching control chip to operate. This often leads to stability and noise issues in projection systems with color wheels.

[0043] In addition, projection systems with color wheels require power for both the motor and the control chip, leading to increased power consumption in the light source system.

[0044] In view of the above problems, this application provides a lighting source.

[0045] Please refer to Figure 1The schematic diagram of the illumination source 100 provided in this application embodiment shows that the illumination source 100 may include a color light conversion element 110, an optical control element 120, and a light guiding module (not shown). The color light conversion element 110 may include at least two color partitions (including three color partitions, RGB, as shown in the figure). The optical control element 120 is disposed in the front optical path of the color light conversion element 110 and includes control partitions (120-1, 120-2, 120-3) corresponding to the color partitions. The light guiding module is used to guide the initial light beam to the optical control element 120, and to guide at least a portion of the emitted light beam from the control partitions to the color partitions in the color light conversion element 110 corresponding to those control partitions.

[0046] Since the color conversion element 110 includes at least two color zones, when a color zone emits a beam, the corresponding control zone is in an open state. When a color zone does not emit a beam, the corresponding control zone is in a closed state. By controlling the open or closed states of multiple control zones of the optical control element 120 in a timing manner, spatially separated time-separated colored beams can be formed on the emission side of the color conversion element 110. The color conversion element 110 is used to provide colored beams to downstream optical components.

[0047] Specifically, the optical control element 120 may include multiple control zones, and for each control zone, there is a corresponding color zone. That is, the control zone can guide the initial light beam incident on it to the color zone corresponding to the control zone, and the control zone can control whether the corresponding color zone emits a light beam by being in an on or off state.

[0048] The initial light beam is guided by the light guiding module and incident on the optical control element 120. When a control zone is in the open state, the corresponding color zone emits a light beam; when a control zone is in the closed state, the corresponding color zone does not emit a light beam. By controlling the open and closed states of different control zones in the optical control element 120, the initial light beam can be sequentially emitted from the control zones of the optical control element 120 to the corresponding color zones, forming spatially separated, time-sequential colored light beams.

[0049] For example, the color conversion element 110 may include two color partitions. Correspondingly, the optical control element 120 may also include two control partitions, with each control partition in the optical control element 120 corresponding one-to-one with the two color partitions in the color conversion element 110. When the color conversion element 110 includes three color partitions as shown in the figure, the three color partitions can be red partition R, green partition G, and blue partition B. Correspondingly, the optical control element 120 also has three control partitions, and the three control partitions (120-1, 120-2, 120-3) correspond one-to-one with the red partition R, green partition G, and blue partition B of the color conversion element 110, respectively. The control partitions are judged based on whether they can be controlled consistently. By controlling them in an on or off state, the corresponding color partition can be controlled to emit a light beam.

[0050] Specifically, in one embodiment of the present invention, the optical control element 120 includes an optical phase control element. The optical phase control element includes a liquid crystal layer and multiple independent control zone driving circuits, with each control zone driving circuit corresponding to a specific control zone. The control zone driving circuit controls the electric field of the liquid crystal layer in the corresponding control zone, thereby controlling the exit phase of the initial light beam incident on that control zone. Specifically, the optical control element 120 can be an LCoS or LCD type optical phase control element, controlling the voltage on opposite sides of the liquid crystal layer through the driving circuit to control the rotational orientation of the liquid crystal molecules, thereby controlling the polarization state of the light passing through the liquid crystal layer.

[0051] Alternatively, in another embodiment of the invention, the optical control element 120 includes a micro-opto-electro-mechanical system (MEMS) element. The MEMS element includes a micromirror array and multiple independent control zone drive circuits, each corresponding to a control zone. The control zone drive circuits control the electrode voltage of the micromirror array in the corresponding control zone, thereby controlling the exit angle of the initial light beam incident on that control zone. Specifically, the optical control element 120 can be a DMD-type MEMS element.

[0052] In one embodiment, each control zone of the optical control element 120 includes multiple control sub-zones with interconnected driving circuits. Under the control of the control zone driving circuits, the state changes of each control sub-zone within the same control zone are consistent. Whether it's an optical phase control element similar to an LCoS / LCD or a micro-opto-electro-mechanical system element similar to a DMD, conventional products contain many pixels, controlling the switching of each pixel. In this embodiment, however, by connecting circuits containing a large number of pixels in series to control the switching of the control sub-zone together, costs can be reduced and data processing speed can be improved.

[0053] In the above embodiments, the control zones and color zones correspond one-to-one and are equal in number, enabling precise control of each color zone. In another embodiment of this application, the lighting source 100 includes an optical control element 120 comprising multiple control zones, and a color conversion element 110 comprising at least two color zones, wherein at least two control zones correspond to the same color zone. By having at least two control zones correspond to the same color zone, brightness control of a single color can be achieved. For example, when two control zones correspond to the same color zone, there are three possible scenarios: First, both control zones are simultaneously in an on state; second, one control zone is in an on state, and the other is in a off state; third, both control zones are simultaneously in an off state. In the first scenario, the light beam emitted by that color zone reaches 100% brightness. In the second scenario, the light beam emitted by that color zone reaches 50% brightness. In the third scenario, that color zone does not emit a light beam. This technical solution can add a dimension to control the brightness of color zones. The more control zones a color zone corresponds to, the higher the precision of the adjustable brightness, but the system complexity will also increase. It is not necessarily better to have more. The number of control zones a color zone corresponds to should not exceed 16 (corresponding to 4 binary bits).

[0054] In the above-described embodiments, the light emission of each color partition can be independently controlled, allowing for independent emission periods for any one of the red, green, or blue colors. This naturally results in sequential red, green, and blue colored light, which can be applied to projection optical paths where the back-end optical path includes only one spatial light modulator 220. When controlling two colors from the red, green, and blue color partitions to emit light simultaneously, the illumination source 100 can also be applied to projection optical paths where the back-end optical path includes two spatial light modulators 220. When controlling all three colors from the red, green, and blue color partitions to emit light simultaneously, the illumination source 100 can also be applied to projection optical paths where the back-end optical path includes three spatial light modulators 220. In another embodiment of the invention, one control partition can correspond to at least two color partitions. In this technical solution, at least two color partitions corresponding to the same control partition can only be in an on or off state simultaneously. This technical solution can be applied to projection optical paths of multi-chip spatial light modulators, as well as to application scenarios that utilize multiple color partitions to achieve mixed colors. For example, when a control zone corresponds to both a red and a green color zone, and it is in the "on" state, the color conversion element emits both red and green light simultaneously. After entering the back-end optical path, the red and green light can be split into two optical paths by the wavelength splitting element, which then reach two spatial light modulators for modulation. This is one type of application. When a control zone corresponds to both a red and an orange color zone, and it is in the "on" state, the color conversion element emits both red and orange light simultaneously. The red and orange light can be mixed and then reach the same spatial light modulator or other lighting output, thereby improving the color coordinates of the original red light. This is another type of application.

[0055] Alternatively, please continue to refer to Figure 1 The illumination source 100 may further include a light-emitting element 140. The light-emitting element 140 is disposed in the front optical path of the optical control element 120 and is used to emit an initial light beam. A light guiding module guides the initial light beam emitted by the light-emitting element 140 to cover all control zones of the optical control element 120. When the light-emitting element 140 emits white light, the color conversion element 110 may be a filter element having at least two color zones. Alternatively, when the light-emitting element 140 emits excitation light, the color conversion element 110 may be a fluorescent plate having at least two fluorescent regions or a fluorescent plate having at least one fluorescent region and one scattering region. For example, when the light-emitting element 140 emits blue excitation light, the color light conversion element 110 can be a fluorescent plate including a red fluorescent region, a green fluorescent region, and a scattering region, wherein the scattering region is used to homogenize the blue light so that its light distribution is approximately the same as the emitted light distribution of the red fluorescent region and the green fluorescent region; when the light-emitting element 140 emits ultraviolet excitation light, the color light conversion element 110 can be a fluorescent plate including a red fluorescent region, a green fluorescent region, and a blue fluorescent region.

[0056] The illumination beam emitted from the light-emitting element 140 can be guided to the optical control element 120 by the light guiding module. In other optional embodiments, the illumination beam can also be directly emitted to the optical control element 120.

[0057] In this embodiment, a light-emitting element 140 capable of adjusting the light intensity and switching time can be selected. For example, a laser diode or light-emitting diode capable of emitting an excitation beam can be used. During use, the illuminance emitted by the illumination source 100 can be changed by adjusting the current amplitude flowing through the laser diode / light-emitting diode or by adjusting the pulse duty cycle flowing through the laser diode / light-emitting diode.

[0058] When the initial light beam emitted from the light-emitting element 140 is incident on the optical control element 120, the control zone corresponding to the color zone to be emitted is activated, so that the light beam is guided to the corresponding color zone through the control zone. In this case, the illumination beams emitted to other control zones in the optical control element 120 are not utilized, which will cause a certain degree of reduction in optical efficiency.

[0059] To improve optical efficiency and address the aforementioned problems, a light recovery device (not shown) may optionally be provided between the light-emitting element 140 and the optical control element 120.

[0060] Specifically, a light recovery device is disposed in the optical path between the light-emitting element 140 and the optical control element 120. The light recovery device is used to recover at least a portion of the light beam emitted from the optical control element 120 that has not entered the color conversion element, and to re-homogenize and emit it back into the optical control element 120.

[0061] When a portion of the light beam emitted to other control zones in the optical control element 120 is not utilized, that portion of the light beam can be recovered by the light recovery device. The light recovery device then re-homogenizes the recovered light beam before it is emitted back onto the optical control element 120, thereby improving the optical efficiency of the illumination source 100.

[0062] For example, a tapered light guide can be provided between the optical control element 120 and the light guiding module so that the light beam can be re-emitted into the optical control element 120 after multiple internal reflections. It should be noted that when the optical control element 120 includes a light phase control element with a liquid crystal layer and multiple independent control zone driving circuits, a polarization element needs to be provided at the exit position of the light recovery device so that the light beam undergoes polarization conversion at the exit of the light recovery device.

[0063] Furthermore, please continue to refer to Figure 1 The lighting source 100 provided in this application embodiment may also include a relay optical element 130.

[0064] The relay optical element 130 is disposed in the rear optical path of the color conversion element 110. The relay optical element 130 may include a pair of compound eye lenses, and the light entering different compound eyes overlaps and forms an image at a certain position in the rear optical path of the pair of compound eye lenses.

[0065] The relay optical element 130 can achieve the overlapping of the surface distribution of the colored light beams emitted from the optical control element 120 and the color light conversion element 110 at a certain spatial position, which is beneficial for the uniform projection of the light beams of each unit lens of the compound eye lens onto the downstream spatial light modulator 220.

[0066] The lighting source 100 provided in this application embodiment adopts a combination of optical control element 120 and color light conversion element 110 to guide the lighting beam emitted from the light-emitting element 140 through different control zones of optical control element 120 to different color zones of color light conversion element 110 in a time sequence, so as to form spatially separated time-sequential colored light.

[0067] By setting multiple control zones corresponding to color zones on the optical control element 120, the initial beam emitted from the light-emitting element 140 can be incident and cover all control zones of the optical control element 120 through the light guiding module. By controlling whether the control zone is in an open or closed state, the control of the color zone corresponding to that control zone is more independent, and different color zones are controlled independently, making operation simple.

[0068] Furthermore, the reduced number of on / off states in each control zone enhances the controllability of each color zone, resulting in a simpler architecture and more stable operation for the lighting source 100. Using this lighting source 100 can replace traditional color wheels or galvanometers, improving overall operational stability and reducing production costs.

[0069] Please refer to Figure 2 This application also provides a projection system 200. The projection system 200 may include a spatial light modulator 220 and the aforementioned illumination source 100.

[0070] The spatial light modulator 220 is located in the rear optical path of the illumination source 100. The spatial light modulator 220 is used to receive the timed color beam emitted by the illumination source 100, modulate it, and then modulate the received timed color beam according to the image data so that the modulated emitted image light is emitted. Each image frame of the image data includes multiple color subframes to correspond to multiple color time sequences emitted by the illumination source 100.

[0071] Furthermore, please continue to refer to Figure 2 The projection system 200 may also include a projection screen 230.

[0072] The projection screen 230 is disposed on the rear optical path of the spatial light modulator 220 and is used to display the color beam modulated by the spatial light modulator 220.

[0073] It is understood that the projection screen can be a physical screen or a virtual projection location. For example, when a wall is used as the projection surface, the wall becomes the projection screen. Optical components such as a projection lens may also be included between the projection screen 230 and the spatial light modulator 220.

[0074] The foregoing has described an overview of various embodiments of the lighting source and projection system of the present invention. The lighting source and projection system will now be described in conjunction with specific embodiments. Specifically, as shown below... Figure 3 The projection system 200 provided in this application embodiment includes an illumination source 100 and a spatial light modulator 220, with the spatial light modulator 220 located in the rear optical path of the illumination source 100.

[0075] In this first embodiment, the illumination source 100 includes a color conversion element 110, an optical control element 120, a light-emitting element 140, a relay optical element 130, and a light guiding module. Specifically, the optical control element 120 is an optical phase control element based on LCoS technology, and the light guiding module includes a first polarization beam splitter 150 (as shown in the figure, a polarization beam splitter prism). The first polarization beam splitter 150 has polarization selectivity and can reflect S-polarized light and transmit P-polarized light.

[0076] The light-emitting element 140 emits an S-polarized beam. The first polarization beam splitter 150 is used to reflect and guide the beam emitted by the light-emitting element 140 to cover all control zones of the optical control element 120. At the same time, it can also guide the P-polarized beam emitted by the optical control element 120 to be emitted onto the color light conversion element 110.

[0077] It is understandable that the first polarization beam splitter 150 can also transmit S-light and reflect P-light. In this case, the light-emitting element 140 emits a P-polarized beam that reaches the first polarization beam splitter 150.

[0078] As shown in the figure, the optical control element 120 includes three partitions 120-1, 120-2, and 120-3, corresponding to the three partitions R, G, and B of the color conversion element 110, respectively. In this embodiment, the color conversion element 110 has a transmissive structure, meaning its light incident surface and light emitting surface are two surfaces arranged opposite each other. At different times, different color partitions of the color conversion element 110 emit red, green, and blue light respectively, with each color beam spatially separated from the others. This spatially separated temporal light, through the relay optical element 130, achieves surface overlap at the incident surface of the spatial light modulator 220, thereby obtaining spatially overlapping temporal colored beams. In this embodiment, the relay optical element 130 includes a compound eye lens pair 160 and an imaging lens 170 (which can be a single lens or a lens group). The compound eye lens pair 160 includes two sets of microlens groups arranged front and rear. The microlens groups spatially divide the light beams of each color into small beams corresponding to the microlenses, which are then imaged onto the incident surface of the spatial light modulator 220 by the imaging lens 170. During this process, after the incident light spot of each microlens is magnified and imaged, it covers the light incident surface of the spatial light modulator 220. The magnified images formed by the small beams corresponding to each microlens overlap with each other on the light incident surface of the spatial light modulator 220, which on the one hand achieves the effect of uniform light, and on the other hand makes the originally spatially separated red, green and blue light beams overlap with each other. It can be understood that the overlap described in this invention includes the case of basic overlap. In reality, it is impossible to achieve perfect overlap between two light spots. It is sufficient to achieve the standard of light spot uniformity at the incident surface of the spatial light modulator. For example, in this invention, the light spot within the effective light spot range (i.e., pixel display area) of the incident surface of the spatial light modulator can satisfy the condition that the larger of [(maximum illuminance - average illuminance) / average illuminance] and [(average illuminance - minimum illuminance) / average illuminance] does not exceed 1%.

[0079] The projection system 200 also includes a second polarization beam splitter 250, which is located between the illumination source 100 and the spatial light modulator 220. The second polarization beam splitter 250 can reflect S-polarized light beams and transmit P-polarized light beams. When a P-polarized light beam emitted from the illumination source 100 is incident on the second polarization beam splitter 250, the second polarization beam splitter 250 transmits the P-polarized light beam and guides the beam into the spatial light modulator 220. The spatial light modulator 220 converts the P-polarized light beam into S-polarized image light according to the image data and emits it to the second polarization beam splitter 250. The second polarization beam splitter 250 then reflects the S-polarized image light and guides it out.

[0080] In this embodiment, the spatial light modulator 220 is an LCoS, which belongs to the same technical category of optical elements as the optical control element 120. Compared to a combined system of optical elements of different technical categories, a combined system of optical elements of the same technical category can reduce the overall cost and also reduce the computation of control signals.

[0081] Please participate again. Figure 3 In this embodiment, the optical control element 120 and the spatial light modulator 220 both belong to the optical phase control element, which requires that the incident light must be light with a single polarization state. As described above, the present invention can adopt a technical combination scheme in which the light-emitting element is white light and the color light conversion element is a filter device, or it can adopt a technical combination scheme in which the light-emitting element is excitation light and the color light conversion element includes fluorescent material. For the former, it is necessary to make the white light emitted by the light-emitting element polarized white light, which can be achieved by setting a polarization selector or a polarization conversion device; for the latter, when a laser is used as the excitation source, it itself has a good degree of polarization and does not need to be polarized, but the emitted light of the fluorescent material is unpolarized light, so a polarization conversion device needs to be set in the emitted light path of the color light conversion element so that the light with a single polarization state is incident on the LCoS.

[0082] The projection system 200 also includes a projection lens 270 for imaging the image emitted by the spatial light modulator 220 onto a preset position, thereby forming a projected image.

[0083] like Figure 4 In another embodiment, the projection system 200 can also employ a reflective optical path structure. In this embodiment, the color conversion element 110 is a reflective structure, meaning that its light incident surface and light emitting surface are the same surface.

[0084] Specifically, the projection system 200 may include a light-emitting element 140, a first polarizing beam splitter 150, an optical control element 120, a beam splitter 180, a color light conversion element 110, a compound eye lens pair 160, a second polarizing beam splitter 250, a spatial light modulator 220, and a projection lens 270. The spatial light modulator 220 may be an LCoS panel. The color light conversion element 110 is a reflective phosphor panel, including a fluorescent area facing the optical control element 120 and a reflective substrate facing away from the optical control element 120.

[0085] An optical control element 120 is located in the front optical path of the color light conversion element 110, and the reflecting surface of the optical control element 120 is perpendicular to the reflecting surface of the color light conversion element 110. A first polarization beam splitter 150 and a beam splitter 180 are sequentially arranged between the optical control element 120 and the color light conversion element 110. A relay optical element 130, including a compound eye lens pair 160 and an imaging lens 170, is arranged in the rear optical path of the color light conversion element 110. A spatial light modulator 220 is arranged in the rear optical path of the relay optical element 130. A second polarization beam splitter 250 is arranged between the relay optical element 130 and the spatial light modulator 220. A projection lens 270 is arranged in the rear optical path of the spatial light modulator 220.

[0086] exist Figure 4 In the structure shown, the initial beam emitted from the light-emitting element 140 is perpendicular to the emission direction after reflection by the optical control element 120. In this embodiment, the optical paths before and after the optical control element 120 and the spatial light modulator 220 can be referenced as described above. Figure 3 The description of the embodiments is as follows. The main difference between this second embodiment and the first embodiment is that the color light conversion element 110 is a reflective type, and the matching optical paths before and after the color light conversion element 110 are as follows.

[0087] There are two main technical solutions for the combined excitation light and phosphor system.

[0088] When the excitation light is UV excitation light and the color conversion element 110 includes a blue fluorescent region, a green fluorescent region and a red fluorescent region, the beam splitter 180 is a wavelength beam splitter that transmits UV excitation light and reflects visible light. After the excitation light is incident on different fluorescent regions of the color conversion element 110, the laser emitted by different fluorescent regions is collected by the collecting lens, returns to the beam splitter 180 and is reflected to the relay optical element 130.

[0089] When the excitation light is blue, and the color conversion element 110 includes a scattering region, a green fluorescent region, and a red fluorescent region, the beam splitter 180 is a wavelength splitter with regional coating. A small region on the beam splitter 180 is coated with a coating that transmits blue light and reflects red and green light, while other regions are coated with a coating that reflects red, green, and blue light. This allows the excitation light to pass through this small region and be incident on the color conversion element 110. The red and green light emitted from the color conversion element 110 is directly reflected by the beam splitter 180 to the relay optical element 130, while the blue light emitted from the color conversion element 110 is partially lost through transmission in the aforementioned small region, and the rest is reflected to the relay optical element 130.

[0090] Optionally, in Embodiments 1 and 2 above, the optical control element and spatial light modulator can be LCoS. It is understood that LCoS can also be replaced by MOEMS (Micro Optic Electro Mechanical System), such as a micromirror array (DMD). Alternatively, the optical control element can use LCoS technology while the spatial light modulator uses MOEMS / LCD, or vice versa. The optical path principle is largely the same and will not be elaborated here. It should be noted that when the optical control element uses LCD technology, the light incident surface and light exit surface of the optical control element are two opposing surfaces. Therefore, the light guiding module includes at least a portion of the optical path located at the front end of the optical control element and a portion of the optical path located at the rear end of the optical control element. However, the main difference lies in the optical path; the inventive principle of this invention is the same regardless of whether LCoS, LCD, or MOEMS technology is used.

[0091] The modulation method of the projection system described above is described below.

[0092] During a color subframe of the projection system, the luminous flux of the beam emitted to the spatial light modulator can be adjusted by controlling the time ratio of the on and off states of the control partition in the optical control element corresponding to the color subframe.

[0093] During an image frame, the time proportion of different color subframes is controlled by controlling the time proportion of different control partitions being in the open state, based on the image data.

[0094] By dynamically adjusting the proportions of each color subframe using image data, light utilization and color brightness can be improved. Since the proportions of each color are fixed in typical time-series image displays, the projection system provided in this application can adjust colors according to different images. For example, for a red image, the duty cycle of the red sequence can be increased (i.e., the on state time of the corresponding control partition can be increased), while correspondingly reducing the duty cycles of the blue and green sequences.

[0095] Since the angle of the color wheel is determined by the physical structure, it cannot be changed dynamically. Compared to the color wheel, this projection system offers greater adjustment flexibility.

[0096] When an optical control element includes multiple control zones, and the multiple control zones correspond one-to-one with the multiple color zones of a color light conversion element, the illumination flux input to downstream optical components (e.g., spatial light modulators) can be adjusted by controlling the time ratio of the on and off states of the emitted light beams in each control zone according to the time sequence.

[0097] It is understandable that, in addition to adjusting the luminous flux by controlling the on / off state and duty cycle of the control partition corresponding to a color subframe during a color subframe, it is also possible to control at least two control partitions to be on simultaneously during a color subframe, with each of these two control partitions corresponding to a different color partition, thereby obtaining colors other than the three primary colors of RGB.

[0098] In addition to the standard RGB primary colors, traditional color wheels also include RGBW or RGBY structures. However, these require an additional mixing color area, such as the W segment (allowing visible light to enter the back-end optical path) or the Y segment (allowing yellow light to enter the back-end optical path). This invention, however, eliminates the need for separate control zones for mixing colors. For example, in the W (white) segment, all control zones can be turned on, allowing the three primary colors (red, green, and blue) to illuminate together, resulting in white light. Increasing the amount of white light improves the overall brightness. Similarly, in the Y (yellow) segment, the control zones corresponding to the red and green color zones can be turned on, allowing red and green to illuminate together, resulting in yellow light. This improves the control range of the projection system.

[0099] Different colors of image light can be adjusted by controlling the duty cycle of a single color subframe in the spatial light modulator. That is, the modulation method used in the projection system provided in this application embodiment can, on the one hand, control the illumination flux reaching the spatial light modulator by controlling the on / off state and duty cycle of the optical control elements; on the other hand, the duty cycle or transmittance of each pixel in the color image can be adjusted by using the spatial light modulator, thereby achieving color image modulation.

[0100] Taking LCoS as an example of optical control elements, the response time of LCoS is slower than that of laser diodes or other electronic devices. Therefore, in some cases, some control zones of the LCoS can be turned off, leaving only one open. Simultaneously, to improve the slow response time, the light-emitting element, LCoS reflector, and LCoS imager need to be synchronized. However, improper operation can lead to LCoS light leakage.

[0101] To avoid issues such as light leakage and color crosstalk in LCoS, and to reduce image jitter.

[0102] like Figure 5 As shown, when the control zone in the optical control element switches between an on and off state, the initial beam emitted to the control zone is shut off. That is, when the control zone of the optical control element switches to the ON region, the initial beam emitted to the optical control element is shut off. Simultaneously, downstream optical components (e.g., spatial light modulators) are not activated, thus avoiding color crosstalk and LCoS light leakage problems.

[0103] In other words, the light source can be blanked before the LCoS control zone changes to the next control zone. That is, during the blanking period when the light source is off, the LCoS reflector sets the corresponding modulation conditions for the next color slot of the control zone, so that each control zone has time to respond to the ON and OFF states respectively, and different control zones respond sequentially as needed. When the light source is turned back on, the LCoS imager is ready to modulate the new color.

[0104] like Figure 5 The figure shows the waveform of the switching and light source synchronization modulation of LCoS.

[0105] In the waveform diagram, "Time 1", "Time 3", "Time 5" and "Time 7" are the time slots when the "light source" is turned off.

[0106] When the three control zones in the LCoS, which correspond one-to-one with the RGB color zones of the color light conversion element 110, are turned on in sequence, the light source is turned off during the turn-on or turn-off time gap between two adjacent control zones, and is turned on again after the steady state is reached.

[0107] When the light source is turned on, only one control zone corresponding to a color zone will reflect the illumination beam. Therefore, light leakage in LCoS can be avoided.

[0108] In another embodiment, the optical control element can be an MOEMS. For example... Figure 6 The figure shows the waveform of the switching and light source synchronization modulation of MOEMS. Similar to LCoS, the response time of MOEMS is slower than that of laser diodes or other electronic devices. The above-mentioned method of turning off the power can also be used to avoid light leakage of MOEMS.

[0109] Each control zone of MOEMS requires the coordinated action of three electrodes to control its activation. The specific modulation method of MOEMS is similar to that of LCoS, and will not be elaborated here.

[0110] The illumination source 100 and projection system 200 provided in this application embodiment replace the color wheel with the illumination source 100 formed by the combination of optical control elements and color light conversion elements. This is beneficial to improving the stability of the system and reducing production costs. In addition, the system is small in size and easier to construct.

[0111] In summary, the projection system 200 provided in this application embodiment emits an illumination beam from the light-emitting element 140 onto the optical control element 120. By opening or closing the control partitions in the optical control element 120, the beam emitted onto the color partitions of the color conversion element 110 is adjusted, thereby forming a spatially separated temporally colored beam. Then, after color image modulation by the spatial light modulator 220, the image can be displayed on the projection screen. Moreover, the projection system 200 is a single-source reflection system. By replacing the color wheel with the illumination source 100, mechanical moving parts in the traditional structure are eliminated, such as the motor and motor control chip, simplifying the system structure; reducing power loss and production costs; improving the overall system's operational stability; and reducing the system's size. The system is also easier to construct compared to traditional structures with color wheels. The projection system 200 can modulate the light source 210 as needed, and the modulation is convenient to obtain a spatially separated temporally colored beam.

[0112] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A lighting source, characterized in that, include: A color light conversion element, wherein the color light conversion element includes at least two color zones; and An optical control element is disposed in the front optical path of the color conversion element. The optical control element includes multiple control zones, and for each control zone, there is a corresponding color zone. A light guiding module is used to guide an initial light beam to the optical control element and guide at least a portion of the emitted light beam from the control zone to its corresponding color zone; When a color zone emits a light beam, the control zone corresponding to that color zone is defined as being in an open state; when a color zone does not emit a light beam, the control zone corresponding to that color zone is defined as being in a closed state. By controlling the state of the multiple control zones of the optical control element in a timing sequence, spatially separated timing color beams can be formed on the emission side of the color light conversion element.

2. The lighting source according to claim 1, characterized in that, The optical control element includes an optical phase control element, which includes a liquid crystal layer and multiple independent control partition driving circuits. Each control partition driving circuit corresponds to a control partition, and the control partition driving circuit controls the electric field of the liquid crystal layer of the corresponding control partition, thereby controlling the exit phase of the initial light beam incident on the control partition. or, The optical control element includes a micro-opto-electro-mechanical system (MEMS) element, which includes a micro-mirror array and multiple independent control zone drive circuits. Each control zone drive circuit corresponds to a control zone, and controls the electrode voltage of the micro-mirror array in the corresponding control zone through the control zone drive circuit, thereby controlling the exit angle of the initial beam incident on that control zone.

3. The lighting source according to claim 2, characterized in that, Each control zone includes multiple control sub-zones connected in series with drive circuits. Under the control of the drive circuit of the control zone, the state changes of each control sub-zone within the same control zone are consistent.

4. The lighting source according to claim 1, characterized in that, There are at least two of the control partitions corresponding to the same color partition.

5. The lighting source according to claim 1, characterized in that, It also includes a light-emitting element, which is disposed in the front optical path of the optical control element, and the initial light beam emitted by the light-emitting element is guided by the light guiding module to cover the entire control zone of the optical control element; The light-emitting element emits white light, and the color conversion element is a filter element with at least two color zones; or, the light-emitting element emits excitation light, and the color conversion element is a fluorescent plate with at least two fluorescent regions or a fluorescent plate with at least one fluorescent region and one scattering region.

6. The lighting source according to claim 5, characterized in that, It also includes a light recovery device, which is disposed in the optical path between the light-emitting element and the optical control element. The light recovery device is used to recover at least a portion of the light beam emitted by the optical control element that did not enter the color light conversion element, and then re-homogenize and emit it back to the optical control element.

7. The lighting source according to any one of claims 1-6, characterized in that, It also includes a relay optical element, which is disposed in the rear optical path of the color light conversion element and is used to achieve the overlapping of the light beams emitted from different color zones of the color light conversion element at a preset spatial position to obtain a spatially overlapping temporally colored light beam.

8. A projection system, characterized in that, include: Spatial light modulator; as well as The illumination source according to any one of claims 1-7, wherein the spatial light modulator is located in the rear optical path of the illumination source, and the spatial light modulator is used to receive the time-series color beam emitted by the illumination source and modulate the emitted image light according to the image data, wherein each image frame includes multiple color subframes.

9. The projection system according to claim 8, characterized in that, During a color subframe, the time ratio of the on and off states of the control partition in the optical control element corresponding to the color subframe is controlled to adjust the luminous flux of the light beam emitted to the spatial light modulator.

10. The projection system according to claim 8, characterized in that, During one image frame, the time proportion of different color subframes is controlled by controlling the time proportion of time that different control partitions are in the open state, based on the image data.

11. The projection system according to claim 8, characterized in that, When the control zone in the optical control element switches between an on and off state, the initial beam emitted to the control zone is shut off.

12. The projection system according to claim 8, characterized in that, During a color subframe, at least two of the control partitions are simultaneously in an on state, and the two control partitions correspond to different color partitions.

Images