LED lighting projector

Abstract

The invention relates to a projector for generating a frame of an image. The projector can be used in an augmented reality or virtual reality device. The projector comprises an array of elements arranged in a plane, each element comprising at least three LEDs having different respective colors, and an array of collector structures, each collector structure being configured to receive light from a single LED at any one time and reduce the angle at which the LED emits light. The projector further comprises a projector unit configured to receive light from the array of collector structures and to collimate the light so that a frame is formed. The frame is full color and is formed from a plurality of sub-frames, the sub-frames being formed by spatial movement of the array of elements relative to the array of collector structures so that each collector structure receives light from a different LED during each sub-frame, and / or the sub-frames being formed by displacement of the light emitted from each LED so that the light from each LED illuminates a plurality of pixels of the frame.

Description

Technical Field

[0001] This invention relates to projectors. In particular, it relates to projectors used in waveguide systems. Background Technology

[0002] Projectors used in handheld devices such as mini projectors and wearable devices such as virtual reality (VR) and augmented reality (AR) headsets need to be lightweight and comfortable for users who may hold or wear the device for an extended period of time.

[0003] Currently known projection systems include a light source for generating light, optics for shaping the light into a ray path, a homogenizer for homogenizing these ray paths, and a repeater for relaying the homogenized ray path to the display to be illuminated.

[0004] Ideally, LED arrays would be preferred as the light source for generating light, since LEDs can also produce images, rather than relying on a modulation display that requires a separate illuminator. With the advent of micro-LEDs, their use appears poised to enable increasingly smaller projectors.

[0005] In theory, a self-emissive panel that can both generate light and produce images should allow for improvements in the size of reflective panels, as it eliminates the need for separate components to provide light. This should also result in improvements in image efficiency, brightness, and contrast.

[0006] However, LEDs are Lambertian emitters, thus emitting light over a wide angular range. This can cause system efficiency issues, as a large percentage of emitted light may be lost. Optics can be used to help ensure the maximum amount of emitted light is collected. However, this increases the system size. Additionally, since each LED produces only a single color, multiple LEDs of different colors are needed to generate a single image pixel. This limits the achievable resolution for a system of a given size. Summary of the Invention

[0007] According to one aspect of the invention, a projector for generating frames of an image is provided, the projector comprising: an array of elements arranged in a plane, each element comprising at least three LEDs having different corresponding colors; an array of collector structures, each collector structure configured to receive light from a single LED at any given time and reduce the angle at which the LEDs emit light; and a projector unit configured to receive light from the array of collector structures and collimate the light to form a frame; wherein the frame is panchromatic and is formed by combining a plurality of subframes, the subframes being formed by spatial movement of the element array relative to the array of collector structures such that each collector structure receives light from a different LED during each subframe, and / or the subframes being formed by displacement of light emitted from each LED such that light from each LED illuminates a plurality of pixels of the frame.

[0008] LEDs are Lambertian emitters, thus emitting light over a wide angle range. The collector structure is able to collect the light emitted from the LED, thereby reducing the angle of light emission. This improves the efficiency of the projector because the light emitted by the LED can be effectively collected in the light path toward the display instead of being lost.

[0009] In this way, LED arrays can be arranged in small areas without compromising image resolution, while still providing full-color display, although a single collector structure can only be illuminated by a single LED at any given time. The movement of the array of elements and collectors relative to each other, and / or the displacement of light from each LED, each faster than the frame rate, enables full-color images without loss of resolution.

[0010] The displacement of light can be spatial or angular. For example, spatial displacement can occur before the light is collimated, while angular displacement can occur after the light is collimated.

[0011] Preferably, each of the at least three LEDs has an associated collector structure. In some arrangements, each collector structure may be associated with a single LED. In other arrangements, each collector structure may be associated with a single element, such that for each element, at least three LEDs are associated with the same collector structure. Since only light from a single LED can be collected by a single collector at any given time, this may require relative movement between the collector and the LED.

[0012] Preferably, the projector unit includes optical elements configured to be adjustable to cause a displacement of light emitted from each LED, such that light from each LED illuminates multiple pixels of the frame.

[0013] In this way, despite the presence of different LEDs of different colors, the optical elements cause a displacement of the light, allowing the light to strike multiple pixels in each frame, thus maintaining the resolution of the generated frame. The optical elements can move at a speed that allows them to project light from each LED onto multiple different pixels on the display for a time period equal to or less than the time period for displaying a full-color frame.

[0014] The optical element is preferably a light angle shifter capable of adjusting the angular position of light. For example, the optical element may be an adjustable mirror. The mirror can be configured to switch between multiple positions or orientations to provide displacement of light. Alternatively, any type of electromechanical device can be used, which can be configured to cause a change in the direction of light.

[0015] Alternatively, the displacement can be apparent optical motion. This can be provided by a wobbling wedge. The wobbling wedge can be made of glass. Alternatively, the optical element can be a displacement plate that moves at an angle. For example, a nutation plate can be located after the collector array and before the projector unit. By tilting in different directions, the nutation of the plate can provide displacement of the light.

[0016] The displacement of light can be achieved through yaw rotation (vertical axis) and / or pitch rotation (lateral axis) of optical elements. Therefore, light can undergo yaw and / or pitch rotation. In other words, it can move in the x-direction and / or y-direction. This can depend on the arrangement of the LEDs in the plane. If LEDs of different colors are arranged horizontally in the plane, displacement can be caused by yaw rotation. Alternatively, if LEDs of different colors are arranged vertically in the plane, displacement can be caused by pitch rotation. Alternatively, it can be a combination of pitch and yaw.

[0017] In other arrangements, light from each LED may alternatively (or additionally) illuminate multiple pixels of the frame by moving the collector array and element array relative to the projector unit.

[0018] The projector unit may also include a projector lens and adjustable optical elements. The projector lens converts light from a spatial position into an angular position to form an image frame. Alternatively, in an arrangement where the light emitted from each LED is not displaced, the projector unit may include only a projector lens.

[0019] The element array can be configured to be movable to allow spatial movement of the element array relative to the collector structure array. In this way, the collector structure can be stationary relative to other optics in the projector. Since the collector is stationary, further light shifting to form a frame may not be necessary. The element array may include mechanisms for providing movement. This movement can be along a plane.

[0020] Alternatively, the collector structure array can be configured to be movable to allow spatial movement of the element array relative to the collector structure array. In this way, the elements can be stationary relative to other optics in the projector and the display from which the user sees the light. Movement of the collector array enables the collection of light from each LED during each frame. The element array may include mechanisms for providing movement. This movement may be along a plane.

[0021] In some arrangements, during a first subframe, the collector structure can receive light from a first LED among at least three LEDs; during a second subframe, the collector structure can receive light from a second LED among at least three LEDs; and during a third subframe, the collector structure can receive light from a third LED among at least three LEDs.

[0022] Preferably, each collector receives light from each LED of the element within the same time period. In this way, each subframe can have the same intensity.

[0023] In some arrangements, with n LEDs in an element, there can be n subframes. Therefore, the collector structure and / or element can be moved between n different positions, i.e., the number of different positions is at least equal to the number of LEDs in the element.

[0024] In other arrangements, both the collector structure array and the element array can include mechanisms that make them movable to achieve the aforementioned relative movement.

[0025] In some arrangements, elements are arranged along a first axis extending in a first direction in a plane and a second axis extending in a second direction in a plane, wherein the first and second axes are orthogonal to each other, and each element includes LEDs of different colors arranged along at least the first direction, wherein the elements or collector array is configured to be movable relative to the collector along the first direction. In this way, the resolution of the projector can be increased along the axis, wherein some LEDs on that axis are of different colors from each other. For example, this can be on the x-axis or y-axis. This can be used to restore the resolution on that axis to be equal to the number of LEDs on that axis, although LEDs of different colors can exist on the axis.

[0026] Each element may include LEDs of different colors arranged along a first direction and a second direction, wherein the elements or collector array are configured to be movable along the first and second directions. Therefore, although LEDs of different colors are arranged along each axis, resolution can be increased along both axes.

[0027] Depending on the arrangement of the LEDs, the light displacement can also be in the direction of movement of the elements and collector as described above.

[0028] In some arrangements, each subframe can be a single color. In this way, during each subframe, each collector is illuminated by LEDs of the same color. The combination of each subframe in this color sequence can provide a full-color image.

[0029] In other arrangements, each subframe may include a different color. For example, different collectors may collect light from LEDs of different colors in each subframe, with each collector collecting light from all the different colors of LEDs in a combination of subframes to form a panchromatic image frame.

[0030] Each collector can be associated with a single LED, such that each subframe includes each of the different corresponding colors. In this way, there may be no movement between the LEDs (and elements) relative to the collector structure. In this arrangement, the displacement of light from each LED ensures no loss of resolution. Advantageously, this requires fewer moving parts. This can provide the advantage of the projector being a quieter device.

[0031] In some arrangements, each LED is configured to illuminate a single pixel in each subframe, where the displacement of the light causes the illuminated single pixel to be different in each subframe. In this way, during the first subframe, each LED of each element illuminates a single pixel, and in subsequent subframes, each LED of each element illuminates a different pixel that was illuminated by LEDs of a different color in the previous subframe. This provides a full-color frame. For example, a first pixel may be illuminated by an LED of a first color during the first subframe, and may be illuminated by an LED of a second color during the second subframe.

[0032] In some arrangements, each subframe formed can be shifted by one pixel in the plane. For example, during the first subframe, each LED can illuminate a pixel, and in subsequent subframes, the LED can illuminate pixels adjacent to the pixels in the previous frame. This could be pixels in adjacent columns or adjacent rows. In this way, each subsequent subframe can be translated (or shifted up / down) by a pixel compared to the preceding subframe.

[0033] Preferably, the collector structure array is a microlens array and / or a gradually tapering well structure. Using microlenses reduces the angle of light emitted from the LED. Furthermore, their small size allows them to be used in systems such as microprojectors.

[0034] Alternatively, or in addition to microlenses, the collector structure array can be a gradually tapering well structure array. The walls of the gradually tapering well structure serve as conduits for light emitted from the LED. Preferably, the gradually tapering well structure has a first end configured to receive a light beam from the LED and a second end configured to emit said light beam. The first end is preferably smaller than the second end, such that the light can be spread in both dimensions, and the beam angle is reduced by the gradually tapering well structure. Preferably, the walls of the gradually tapering well structure are glass, in which light is reflected along the walls. Alternatively, the collector can be a gradually tapering light tube, which serves as a conduit for light to pass through. The light tube can also reduce the beam angle and spread the light in both dimensions. Thus, a light collection efficiency is maintained in the collector.

[0035] At least three LEDs can include a red LED, a blue LED, and a green LED. In this way, each frame can be full-color. Alternatively, the LEDs can be red, yellow, and blue. In the case of four LEDs in the element, the additional LEDs can be white.

[0036] Alternatively, the element may include multiple LEDs of the same color. For example, the element may include red, green, blue, and red LEDs. In this arrangement, the collector can be arranged to sequentially collect light from each of the four LEDs of the element for a time period equal to or less than the time period for displaying each individual frame. In this way, each LED can contribute to the subframe. Since red LEDs are less efficient, in some cases, having more than one red LED can improve the efficiency of the image. In other arrangements, any combination of colors can be used.

[0037] Preferably, each element comprises three or four LEDs. In an arrangement with three LEDs, they can be arranged in a row. In this way, the element array can be arranged such that each column can include LEDs of the same color. Alternatively, the three LEDs can be arranged in a column. In this way, the element array can be arranged such that each row can include LEDs of the same color. Alternatively, the LEDs of each element can be arranged diagonally.

[0038] In an arrangement where each element comprises four LEDs, the LEDs can be arranged in a 2x2 configuration in the plane. Each element can have four LEDs arranged in a 2x2 matrix. In other words, each element can have two columns and two rows of LEDs. In other arrangements, the LEDs can be arranged in a 1x3 configuration or a 3x1 configuration as described above. Alternatively, they can be arranged in a 4x1 configuration.

[0039] Preferably, in the first subframe, a first LED of at least three LEDs illuminates the first pixel; in the second subframe, a second LED of at least three LEDs illuminates the first pixel; and in the third subframe, a third LED of at least three LEDs illuminates the first pixel. In this way, each pixel of the image frame is formed by light from LEDs of different colors, thereby forming a panchromatic image.

[0040] Preferably, the LED is a microLED. By using microLEDs coupled to microlens arrays or gradually tapering well arrays, the size of the collecting optics can be reduced. The efficiency of the device is also improved compared to other types of light sources or conventional LEDs. As mentioned above, LEDs are Lambertian emitters, meaning they emit light over a wide angular range, typically 2π steradian. MicroLEDs, when coupled to microlenses or microwell arrays, are not Lambertian emitters and emit over a much smaller angular range, resulting in less light loss.

[0041] In some arrangements, the number of subframes is equal to the number of LEDs in the element. For example, there can be three subframes when there are three LEDs. Therefore, for an element that includes RGB LEDs, the number of subframes can be three.

[0042] In another aspect of the invention, an augmented reality or virtual reality device is provided, including the projector described above.

[0043] According to another aspect, a projector display system is provided, comprising: a display for displaying images; and a projector according to the above aspect.

[0044] The display can be a waveguide. For example, it can be a waveguide used in augmented reality (AR) or virtual reality (VR) devices.

[0045] According to another aspect, a method for generating an image frame using a projector is provided, the method comprising: emitting light from an array of elements arranged in a plane, each element comprising at least three LEDs having different corresponding colors; receiving the light emitted from the element array at an array of collector structures, each collector structure receiving light from a single LED at any given time to reduce the angle of the light emitted by the LED; emitting the reduced-angle light from the array of collector structures; receiving the light from the array of collector structures at a projector unit and collimating the light to form a frame; wherein the frame is panchromatic and is formed by combining multiple subframes, the subframes being formed by spatial movement of the element array relative to the array of collector structures such that each collector structure receives light from a different LED during each subframe, and / or the subframes being formed by displacement of light emitted from each LED such that light from each LED illuminates multiple pixels of the frame. Attached Figure Description

[0046] Figure 1A and Figure 1B These are front and side views of the green LED panel, respectively.

[0047] Figure 2A and Figure 2B These are front and side views of the green LED panel and its corresponding collector, respectively.

[0048] Figure 3A and Figure 3B These are front and side views of LED panels for red, green, and blue LEDs and their corresponding collectors, respectively.

[0049] Figure 4 This is a top view schematic diagram of a projector according to an embodiment of the present invention, showing the projection of an image into a waveguide for viewing by a user;

[0050] Figures 5A to 5C yes Figure 4 The front view of the projector's LED panel and collector array shows the different positions of the collectors relative to the LED panel;

[0051] Figure 5D It is from Figures 5A to 5C A front view of the panchromatic image frame produced by light at each location shown;

[0052] Figure 6 This is a top view schematic diagram of a projector according to another embodiment of the present invention, showing the projection of an image into a waveguide for viewing by a user;

[0053] Figure 7 yes Figure 6 A front view of the projector's LED panel and collector array shown;

[0054] Figure 8A This shows that for such Figure 6 The diagram shows how a projector forms panchromatic image pixels from three different subframes.

[0055] Figure 8B It is from Figure 8A A front view of the panchromatic image frames produced by light in the three different subframes shown;

[0056] Figure 9 Is using Figure 6 The projector shown generates to produce Figure 8B A schematic front view of three sub-frames of the panchromatic image frame shown;

[0057] Figure 10This is a top view schematic diagram of a projector according to another embodiment of the present invention, showing the projection of an image into a waveguide for viewing by a user;

[0058] Figure 11A Is it like this? Figure 10 A schematic front view of the LED panel of the projector shown;

[0059] Figure 11B Is it like this? Figure 10 A schematic front view of the collector array of the projector shown;

[0060] Figure 12A and Figure 12B It shows that for such Figure 10 The diagram shown illustrates the LEDs and collector of the projector, showing the different positions of the collector relative to the LEDs.

[0061] Figures 13A to 13D It shows that for such Figure 10 A frontal schematic diagram showing the movement of the projector collector relative to the LED array;

[0062] Figure 14 It shows that for such Figure 10 The diagram shows a projector converting light from a first position into a light angle shifter that produces a green subframe with increased resolution.

[0063] Figure 15 It shows the result of, as Figures 13A to 13D A frontal schematic diagram showing a series of subframes formed by the collector relative to each position in the LED array and the resulting panchromatic image frames; and

[0064] Figures 16A to 16E This shows that it is possible to increase the amount of... Figures 13A to 13D A schematic front view showing an example of light shift in the resolution of the image produced at each location. Detailed Implementation

[0065] Reference Figures 1A to 3B The difficulties of using LEDs as the image source for a projector are shown and described.

[0066] Figure 1A A front view of the green LED array 2 arranged in a plane is shown. Figure 1B A side view of three green LEDs 2a in array 2 and light 3 emitted from said LEDs is shown. Figure 1A The top of the other accompanying figures includes keys to indicate the color of the LEDs shown in the figures. (As shown from...) Figure 1BAs can be seen, since LEDs are Lambertian emitters, light is emitted from each LED 2a over a wide angular range. This is problematic for use in projection displays because the light from each LED is scattered over a wide area instead of forming a beam required for projection and image formation.

[0067] Figure 2A A front view of the green LED array 2 is shown, illustrating a possible solution to the Lambert emission problem. A collector array 6 is arranged above the green LED array 2. Figure 2B A side view of the arrangement is shown. (As seen from...) Figure 2B It can be seen that collector 6 reduces the angle at which light from LED 2 is emitted. However, as in Figure 2A and Figure 2B As can be seen, the size of LED 2a is small when collector 6 is used to ensure that all light from each LED 2 is collected by its associated collector.

[0068] Figure 2A and Figure 2B The arrangement shown will produce an image of only one color because all the LEDs emit green light. Figure 3A and Figure 3B An arrangement of LED 2 and collector 6 capable of producing a panchromatic image is shown. In this arrangement, LED panel 2 includes green LED 2a, red LED 2b, and blue LED 2c. However, for the same area, compared with... Figure 2A Compared to a single-color panel, the number of LEDs of the same color is reduced by one-third, thus producing an image with one-third the number of full-color pixels in each dimension. For example, if Figure 2A The LED array shown forms an image with 1920 pixels in the horizontal direction (i.e., 1920 LEDs in this dimension). Figure 3A The number of pixels in the image is reduced to 640. This reduces the achievable resolution when a full-color image is required.

[0069] This raises the question of how to use LEDs as the image source for a full-color projector while maintaining the display resolution without significantly increasing the size of the system.

[0070] The purpose of this invention is to overcome these problems in order to provide a projector capable of producing full-color images without compromising the size of the system and the achieved resolution.

[0071] Figure 4 A top view schematic diagram of a projector 1 according to an embodiment of the present invention is shown. The projector 1 is shown as projecting an image onto a waveguide 101. The user 201 then views the image.

[0072] The projector 1 includes an LED panel 2. Next to the LED panel 2 is a collector array 6. Between the collector array 6 and the waveguide 101 is a projector unit including a projector lens 8.

[0073] LED panel 2 generates light, serving as both an image source and a light source. The light from the LEDs is collected by collector 6 to reduce the angle of the light emitted from the LEDs, thus solving the aforementioned Lambertian emission problem. The light from collector 6 is then received at projector lens 8. Projector lens 8 collimates the light, converting the positional (spatial) image into an angular image. At LED panel 2, each pixel of the generated image has a spatial position. After projector lens 8 converts the positional image into an angular image, each pixel is represented by an angle (in azimuth and elevation).

[0074] The image is then projected onto the input grating of waveguide 101. Light is then projected downwards onto waveguide 101, exits at the output grating, and is perceived as an image in the eye of user 201.

[0075] Figure 5A It shows Figure 4 The image shows a front view of the LED panel 2 and collector array 6 of the projector 1. As can be seen, the LED panel 2 has green LEDs 2a, red LEDs 2b, and blue LEDs 2c. The LEDs can be considered to be arranged in elements 10, each element 10 including red LEDs 2b, green LEDs 2a, and blue LEDs 2c. As can be seen, the LEDs 2 of each element 10 are arranged diagonally. However, in other embodiments, they can also be arranged horizontally or vertically. The LED array 2 can be effectively considered as... Figure 2A The same arrangement of green LED 2a is shown, with additional red LED 2b and blue LED 2c placed in the unused space between each green LED 2a. This provides better space utilization because it allows for the placement of each of the three colors of LEDs in a more efficient manner. Figure 2A The same area shown in the layout.

[0076] Each collector structure 6 can only collect light from the LED directly below it. For example... Figure 4 As indicated by arrows 20a and 20b, the LED panel 2 is movable relative to the collector 6. In this way, each LED 2 of element 10 can be positioned sequentially below its associated collector 6, such that light from each LED 2 is collected by the collector 6. This... Figures 5A to 5C It is shown in more detail below.

[0077] exist Figure 5AIn the image, the green LED 2a is located below the collector 6, so that the collector 6 only collects light from the green LED 2a, thus forming a green subframe image.

[0078] exist Figure 5B In the middle, the LED panel 2 has been moved so that the blue LED 2c is located below the collector 6, so that only light from the blue LED 2c is collected in this position, thereby forming a blue subframe image.

[0079] exist Figure 5C In the middle, the LED panel 2 has been moved so that only the red LED 2b is located below the collector 6, so that only the light from the red LED 2b is collected, thereby forming a red subframe image.

[0080] LED panels in Figures 5A to 5C The movement between each position shown can occur at the frame rate or faster than the frame rate. Therefore, each of positions 5A to 5C is responsible for generating a single-color subframe. By combining each subframe, a result is produced as shown... Figure 5D The panchromatic frame shown is an example. The number of pixels in the panchromatic frame is equal to the number of collectors 6. Therefore, there is no loss of resolution when generating a panchromatic image.

[0081] Figure 6 A schematic top view of a projector 1 according to another exemplary embodiment of the present invention is shown. The projector 1 is shown to project an image into a waveguide 101, which is then viewed by a user 201.

[0082] Figure 6 The projector 1 shown has an LED panel 2, a collector array 6, and a projector lens 8, similar to Figure 4 The projector shown. Additionally, the projector 1 includes a light angle shifter 12 arranged between the projector lens 8 and the waveguide 101. Figure 6 In the projector 1 shown, and Figure 4 In the different implementation shown, the LED panel 2 is not movable relative to the collector array 6.

[0083] Figure 7 It shows Figure 6 The image shows a front view of the LED panel 2 and collector array 6 of the projector 1. The LED panel 2 includes green LEDs 2a, red LEDs 2b, and blue LEDs 2c. The LEDs are arranged alternately such that no two LEDs of the same color are arranged adjacent to each other in the x and y directions. Figure 7 As can be seen, in each row, green LED 2a, red LED 2b, and blue LED 2c can be considered as component 10. However, this classification of components can also be viewed in columns rather than rows.

[0084] exist Figure 6 and Figure 7 In the projector 1 of the illustrated embodiment, each LED has a corresponding collector 6, such that each collector 6 always collects light from the same LED 2.

[0085] The light angle shifter 12 can shift the light emitted from each LED after passing through the collector 6 and the projector lens 8. For example... Figure 8A As can be seen, the light from each color LED is shifted, so that each pixel of the image formed by the projector is illuminated by light from each color LED. In each subframe, light from a different color LED illuminates each pixel. This provides a full-color image, such as... Figure 8B As shown, it has the same pixel density as the number of collectors (and the number of LEDs). Therefore, the resolution increases to 1920×1920, instead of the 640×640 resolution achieved without displacement.

[0086] Figure 9 It shows how to use Figure 6 A schematic front view of an example method for a projector to obtain a combination of pixels of different colors. Subframe 15a is formed by multiple pixels 22, each of which is illuminated by an LED of a different color.

[0087] Subframe 15b is formed by angularly shifting the light from each LED, such that a light angle shifter shifts the light from each LED by one pixel in the horizontal direction. This can be achieved by yaw rotation. Since the LEDs are arranged in the panel in the order of green, red, and blue, by shifting the subframe by one pixel, pixels previously illuminated by the first color will now be illuminated by LEDs of a different second color. In the final third subframe 15c, the light is further angularly shifted, causing the image to be horizontally shifted by another pixel, so that the last of the three colors illuminates each pixel. This produces... Figure 8B The image frame shown is entirely white and has the same number of pixels as the collector (and LEDs).

[0088] like Figure 9 As can be seen, neither of the two columns of pixels on any one side is illuminated by every three colors of LED, resulting in the image resolution not being exactly the same as the resolution of the number of LEDs. However, when forming an image of 1920 pixels, these four redundant pixel columns have a negligible effect.

[0089] The angular shift between each subframe 15a, 15b, and 15c can occur at 3 times the frame rate, so that each subframe 15a, 15b, and 15c is formed within 1 / 3 of the time it takes to display each frame.

[0090] As each subframe 15a, 15b, 15c is shifted one pixel relative to each other, each LED emits light relative to the pixel it illuminates. For example, consider the first green LED 2a in frame 15a, which emits light representing the first top-left pixel of the original image to be projected. In frame 15b, green LED 2a emits light representing one pixel inward from the top-left corner of the original image to be projected, and in subframe 15c, green LED 2a emits light representing two pixels inward from the top-left corner of the original image to be projected. This ensures that each pixel in the final image represents a single pixel in the original image to be projected.

[0091] exist Figure 6 In the projector shown, the light angle shifter 12 is a mirror configured to move in the appropriate position. Light from the collector is then reflected away from the mirror by different amounts depending on the orientation of the mirror, thus causing the light to shift.

[0092] When the mirror is in the first position, it does not cause a shift in light, such that each collector (and therefore its associated LED) forms a pixel in the image as shown in subframe 15a. Subframe 15b is formed when the mirror moves to the second orientation, and finally, a third subframe 15c is formed when the mirror is oriented in the third position. The light's angle shift is caused by reflection from the mirror, depending on the mirror's orientation.

[0093] Figure 10 A schematic top view of a projector 1 according to another exemplary embodiment of the present invention is shown. The projector 1 is shown to project an image into a waveguide 101, which is then viewed by a user 201.

[0094] Figure 10 The projector 1 shown has an LED panel 2, a collector array 6, a projector lens 8, and a light angle shifter 12, similar to... Figure 6 The projector shown. Figure 10 In the projector 1 shown, and Figure 6 Unlike the projector 1 shown, the collector array 6 is movable, while the LED panel 2 is stationary.

[0095] Figure 11A It shows Figure 10 The image shows a front view of the LED array 2 of the projection display 1. As can be seen, the LED array includes LEDs of different colors. Figure 11AIn the example shown, the LEDs are red, green, and blue. The LEDs are arranged as elements 10, each element consisting of a 2×2 square LED array as shown by the dashed square 10. Each element 10 includes two red LEDs 2b and 2d, one green LED 2a, and one blue LED 2c. Elements 10 are repeated on the LED array. The LEDs in this orientation are tightly packed such that there is no space between adjacent LEDs. With this tightly packed LED array, it is impossible to position the collector over all the LEDs at once.

[0096] Figure 11B A front view of the array of collectors 6 is shown. In this embodiment, more details of collector 6 are shown, illustrating that the collector is a gradually tapering well structure.

[0097] Figure 12A and Figure 12B It shows along such Figure 11A The slice of the first column of LEDs shown is such that only the red 2d LEDs and green 2a LEDs are displayed. The structure of the gradually tapering well structure 6 is shown. Although for... Figure 4 and Figure 6 These details are not shown in the embodiments illustrated, but the collector 6 in these embodiments could also be a gradually tapering well structure.

[0098] like Figure 12A and Figure 12B As can be seen, each tapering well structure 6 includes a conduit 17 extending between an inlet 14 near the LED and an outlet 16 at the LED's distal end. Each tapering well structure has four walls 18a, 18b, 18c, and 18d forming the structure of the tapering well structure 6. The walls of the tapering well structure are tapered such that the cross-sectional area of ​​the outlet 16 is larger than that of the inlet 14. This allows light to be collected from the LED array, reducing the emission angle while increasing the area of ​​light transmission. The walls 18a to 18d of the tapering well structure are formed of glass and are used to contain light within the conduit 17 of the tapering well structure 6.

[0099] As mentioned above, in Figure 10 In the illustrated embodiment, the collector (a gradually tapering well structure) is movable relative to the LED array. This is in Figure 12A , Figure 12B as well as Figures 13A to 13D As shown in the diagram. In other implementations, each collector can only collect light from a single LED at any given time. The reason for this is... Figure 12A and Figure 12B As shown in [the image]. Figure 12AIn this configuration, a tapering well structure 6 is positioned to collect light from the green LED 2a. The entrance 14 of the tapering well structure 6 is located above the green LED 2a, allowing the green light to be collected by the tapering well structure 6. The green light is contained within the tapering well structure by reflection from its walls 18a to 18d. The angle of light emitted from the LED decreases, while the area of ​​light emission increases due to the tapering characteristic of the well structure. In this arrangement, the walls of the tapering well structure are located above the red LED 2d and other red LEDs 2b and blue LEDs 2c (not shown in this view), preventing the collection of light from these LEDs. Figure 12B Different orientations of a tapered well structure 6 relative to the LEDs are shown, wherein the tapered well structure 6 is positioned to collect light from the red LED 2d. In this configuration, the entrance 14 of the tapered well structure 6 collects light from the red LED 2d, while light from the other LEDs 2a, 2b, 2c is blocked by the walls 18a to 18d of the tapered well structure.

[0100] Figures 13A to 13D The image shows a front view of the gradually tapering well structure 6 relative to different positions of the LED array 2. Figure 13A In this configuration, the collectors are positioned above the green LED 2a, such that each collector is illuminated by light from the green LED 2a of its associated element 10. This is as follows: Figure 12A As shown. In Figure 13B In the middle, the collector array has been moved along the plane in the +x direction, so that they are now positioned above the red LED 2b, so that each element 10 of the red LED 2b illuminates the collector. Figure 13C In the diagram, the collector array is moved along the -y direction in the plane such that it is now positioned above the blue LED 2c, so that each element 10 of the blue LED 2c illuminates the collector. Figure 13D In the image, the collector array is moved along the -x direction in the plane so that it is now positioned above the red LED 2d, such that each element 10 of the red LED 2d illuminates the collector. This process is then repeated for the next image frame.

[0101] When the LED spacing (the distance between the centers of two adjacent LEDs) is 3 μm in both the x and y directions, the spacing between the collectors can be 6 μm. Therefore, the collectors can move 3 μm in both the x and y directions to achieve the following: Figures 13A to 13D The movement is shown.

[0102] Figures 13A to 13D The movement speed between each position shown is faster than the frame rate. In fact, the movement speed is four times the frame rate to ensure that the collector is positioned for each frame. Figures 13A to 13DEach position shown.

[0103] like Figure 14 As shown, when the collector is arranged in Figure 13A In the position shown—where the collector is positioned to collect light from the green LEDs—the light angle shifter is configured to cause an angular displacement of the light from the collector in order to increase the resolution of the resulting green subframe. Thus, instead of forming an image with 540 pixels in each direction (which would be the case without the light angle shifter), the image resolution increases to 1080 pixels, making it equal to the number of LEDs in LED array 2. This is shown as green subframe 30a.

[0104] Through the Figures 13A to 13D Each position shown is angularly shifted using a light angle shifter, such as... Figure 15 As shown, four subframes are generated. Subframe 30a is as follows: Figure 14 The green subframe shown. Subframe 30b is when collector 6 is in... Figure 13B The red subframe is formed at the position shown. Subframe 30c is formed when collector 6 is in... Figure 13C The blue subframe is formed at the position shown. Subframe 30d is formed when the collector is in... Figure 13D The red subframes are formed at the positions shown. Each of these subframes is combined to form a panchromatic frame 32. Each of the panchromatic frames and subframes 30a to 30d is 1080×1080 pixels, resulting in no loss of resolution.

[0105] Now about Figures 16A to 16E More details describe how the angle shifter achieves the increased resolution. Figure 16A This illustrates three pixels formed by light emitted from three collectors 6. For example, when in... Figure 13A and Figure 14 At the position shown, this is likely the first three collectors in the top row emitting green light. These three pixels are labeled 33a, 33b, and 33c. As mentioned above, due to the fact that the LED array is 2×2 and only collects a single LED from the 2×2 LED array, this subframe has a resolution of 540 pixels in both the horizontal and vertical dimensions, instead of the expected 1080 pixels.

[0106] The LEDs can be controlled by a signal processor (not shown), which provides signals to control the LEDs to form an image. Figure 16AIn the arrangement shown, the image to be projected is initially reduced to 540×540 pixels, where each projected pixel represents the average of four pixels in the original image. For example, pixel 33a is the average of four pixels in the original image, 33b is the average of four pixels in the original image, and 33c is the average of four pixels in the original image.

[0107] Then the light angle shifter 12 makes the projected light as... Figure 16B The image shows a 1 / 2 pixel translation, so that light is projected to form three pixels 33a, 33b, and 33c, which are relative to... Figure 16A The pixels in the image are shifted at an angle of 1 / 2 pixel. The dashed line indicates the position of the light in the previous projection. When in Figure 16B When projecting at the specified location, the LED is controlled by a signal processor to project a second-sized, scaled-down image of 540×540 pixels, which is based on a one-pixel translation of the original image. In this way, Figure 16B Pixel 33a is the average of the four pixels in the original image, but it starts one pixel inward, i.e., from the second column of pixels in the original image. The other pixels 33b and 33c are also shifted accordingly.

[0108] Then the light angle shifter causes the light to... Figure 16C The image shows a downward shift of 1 / 2 pixel, so that light is projected to form three pixels 33a, 33b, and 33c, which are relative to... Figure 16B The pixels in the image are shifted downwards at an angle by 1 / 2 pixel. When in... Figure 16C When projecting at the specified position, the LED is controlled by a signal processor to project a third-size, scaled-down image of 540×540 pixels, which is based on the original image shifted by one pixel and down by one pixel. In this way, Figure 16C Pixel 33a is the average of the four pixels in the original image, but it starts one pixel inward and one pixel downward, that is, starting from the second row and the second column of the original image. The other pixels 33b and 33c are also shifted accordingly.

[0109] Then the light angle shifter causes the light to... Figure 16D The image shows a 1 / 2 pixel translation, so that light is projected to form three pixels 33a, 33b, and 33c, which are relative to... Figure 16C The pixels in the image are shifted at an angle of 1 / 2 pixel. When in... Figure 16D When projecting at the specified location, the LED is controlled by a signal processor to project a fourth-sized, scaled-down image of 540×540 pixels, which is based on the original image shifted down by one pixel. In this way, Figure 16DPixel 33a is the average of the four pixels in the original image, but it starts one pixel down, i.e., from the second row of pixels in the original image. The other pixels 33b and 33c are also shifted accordingly.

[0110] Figure 16E It is shown that, according to, Figures 16A to 16D This is a portion of the image produced by this shift. As can be seen from this combination of different shifts, the number of pixels 35a and 35b within the image is greatly increased. (This is achieved by targeting...) Figures 13A to 13D Each of these shifts is performed at each position shown, forming each of frames 30a, 30b, 30c, and 30d with a resolution of 1080 on both axes, thus forming a panchromatic 1080 frame 32. By doing this for each image frame, the resolution can be increased from 540×540 to 1080×1080, thus forming a panchromatic image with this increased resolution.

[0111] like Figures 16A to 16D The pixel shift shown above is described as being performed by a light angle shifter that causes an angular shift of the pixel. In an alternative embodiment, Figures 16A to 16D The effect described can be achieved, in fact, by moving light in space rather than by moving it angularly. Besides, for example... Figure 10 as well as Figures 13A to 13D In addition to the relative movement of the collector relative to the LEDs, the effect can also be produced by the movement of the LED array 2 and the collector 6, instead of having a light angle shifter. For example, the LED array 2 and the collector array 6 can be mounted on a mechanism that allows both to move relative to the projector lens 8 in the x and y directions in a plane. This movement can be combined with... Figures 16A to 16D The same as shown, where it moves 1 / 2 pixel in the +x direction (i.e., 1 / 2 of the collimator size), moves 1 / 2 pixel downward in the -y direction, translates 1 / 2 pixel in the -x direction, and then finally returns upward (moving 1 / 2 pixel in the +y direction) to the original position. In this way, it forms as shown... Figures 16A to 16D The pixels shown. By when the collector is in Figures 13A to 13D This movement, performed at each of the positions shown, can achieve, for example... Figure 15 The full-color frame 32 is shown.

[0112] The LEDs shown in all the above embodiments can be micro-LEDs. Due to their small size, micro-LEDs are particularly preferred in micro-projector designs. Each typical micro-LED can have a size of less than 0.04 mm. 2 The area. However, in other arrangements, depending on the projector used, the LEDs can be standard-sized LEDs.

[0113] In the above description, the term "frame" is used to refer to a frame of an image (i.e., an image formed by a projector). This frame can consist of a series of subframes displayed rapidly and continuously, making the frame appear as a still image to the viewer. Frames can be updated in real time at a rate commonly referred to as the frame rate. For example, a projector can operate to display frames at a frame rate of 60 Hz. Therefore, in the above embodiment with three subframes, the subframes can be displayed at 180 Hz. For Figure 4 In the illustrated implementation, the LED can be moved at 180Hz. For Figure 6 The implementation method shown, Figure 9 The shift between each subframe 15a, 15b, and 15c can be 180Hz. For Figure 10 In the embodiment shown, the collector can move at 240 Hz between each location (because there are four locations). Light in Figures 16A to 16D The shift between the positions shown can be 960Hz. This is based on a 60Hz frame rate; other frame rates can be used.

[0114] Various aspects of this disclosure have been described in detail; it will be apparent that modifications and variations may be made without departing from the scope of the aspects of this disclosure as defined in the appended claims.

[0115] In the above about Figure 9 The description illustrates forming a subframe by translating one pixel in the horizontal direction. Alternatively, the shift can be in the vertical direction, which would result in a similar outcome. The shift can depend on the size and orientation of the elements and their respective LEDs.

[0116] The resolutions mentioned above are not limiting, but merely examples. For instance, in describing an increase in resolution from 640×640 to 1920×1920, it should be understood that the original frame can have any resolution, and the corresponding increase can be achieved.

[0117] The collector in the above embodiments is described as a gradually tapering well structure. Alternatively, the collector array can be a microlens array. Microlenses can provide the same effect as a gradually tapering well structure by collecting light from LEDs and reducing their emission angle. Thus, the Lambertian emission problem is solved. In other arrangements, the projector of the above embodiments may include both a microlens array and a gradually tapering well structure array.

[0118] The LEDs shown in the above embodiments are RGB in color. However, the invention is not limited to this, and any combination of colored LEDs can be used. For example, the LEDs can be red, blue, and yellow. Alternatively, in Figure 11A In this configuration, the 2×2 array can contain green, red, blue, and white LEDs.

[0119] Furthermore, each component is not limited to having the color and number of LEDs shown. For example, Figure 10 The illustrated implementation can also be applied to components that are not 2×2. For example, the component could be a 3×1 LED array, such as RGB. In this arrangement, the collector only needs to move in a single direction in the plane, such as the x-direction. Additionally, Figures 16A to 16B The indicated location range will be adjusted to ensure full resolution is achieved.

[0120] In the illustrated embodiment, the displacement of light can be achieved by using methods such as... Figure 6 and Figure 10 The described angle shifter is implemented such as a movable mirror, or it can be a spatial displacement of light, for example, via... Figure 10 The movement of the described LED array and collector is achieved without a light angle shifter. However, as an alternative, displacement can be provided by a shifting plate that moves at an angle. For example, a nutation plate can be located after the collector array and before the projector unit. By tilting in different directions, the nutation of the plate can provide the movement of light, rather than the movement of light from the collector and LEDs by a light angle shifter behind the projector lens. Alternatively, a wobbling glass wedge can be used to provide apparent optical movement. Light enters the glass wedge and can be refracted, thus causing optical displacement of the light. By moving the wedge, the light can be moved in the manner described for the above embodiment to provide the same desired effect. In other arrangements, any mechanism for inducing light displacement can be used.

[0121] exist Figure 4 In the illustrated embodiment, the LED panel is movable, while the collector is stationary. In other arrangements, conversely, the collector is movable, while the LED panel is stationary. However, this may require a light angle shifter or similar mechanism so that the subframes formed by the moving collector overlap each other to form an image.

[0122] about Figures 16A to 16D The arrangement shown and described is an example. Movement can be achieved in any way. Furthermore, the sampling of the displayed images is not limited to the described method.

[0123] In the above embodiment, the projector is shown to project an image onto a waveguide. However, the projector can be used to project light onto any type of device and any type of display, but is not necessarily limited to waveguides.

Claims

1. A projector for generating frames of an image, the projector comprising: An array of elements arranged in a plane, each element comprising at least three LEDs of different corresponding colors; An array of collector structures, each collector structure being configured to receive light from a single LED at any given time and reduce the angle at which the LED emits light; A projector unit configured to receive light from the collector structure array and collimate the light, thereby forming a frame; The frame is full-color and formed by combining multiple subframes, each subframe being a single color. These multiple subframes are formed by spatially shifting the element array relative to the collector structure array, such that each collector structure receives light from a different LED during each subframe. The element array is configured to be movable to provide spatial movement of the element array relative to the collector structure array, and / or the collector structure array is configured to be movable to provide spatial movement of the element array relative to the collector structure array.

2. The projector according to claim 1, wherein, The projector unit includes optical elements configured to be adjustable to cause a displacement of light emitted from each LED, such that light from each LED illuminates a plurality of pixels of the frame.

3. The projector according to claim 1 or 2, wherein, The collector structure array is a microlens array or a gradually tapering well structure array.

4. The projector according to claim 1 or 2, wherein, The at least three LEDs include a red LED, a blue LED, and a green LED.

5. The projector according to claim 1 or 2, wherein, When each element comprises four LEDs, the LEDs are arranged in a 2x2 configuration in the plane.

6. The projector according to claim 1 or 2, wherein, In a first subframe, the first LED of the at least three LEDs illuminates the first pixel; in a second subframe, the second LED of the at least three LEDs illuminates the first pixel; and in a third subframe, the third LED of the at least three LEDs illuminates the first pixel.

7. The projector according to claim 1 or 2, wherein, The LED mentioned is a micro LED.

8. An augmented reality or virtual reality device, comprising the projector of any one of the preceding claims.

9. A projector display system, comprising: A display used to show images; as well as The projector according to any one of claims 1 to 7.

10. A method for generating frames of an image using a projector, the method comprising: Light is emitted from an array of elements arranged in a plane, each element comprising at least three LEDs of different corresponding colors; Light emitted from the element array is received at the collector structure array, and each collector structure receives light from a single LED at any given time to reduce the angle of the light emitted by the LED; Light emitted from the collector structure array at a reduced angle; The projector unit receives light from the collector structure array and collimates the light so that a frame is formed; The frame is full-color and formed by combining multiple subframes, each subframe being a single color. These multiple subframes are formed by spatially shifting the element array relative to the collector structure array, such that each collector structure receives light from a different LED during each subframe. The element array is moved to provide spatial movement of the element array relative to the collector structure array, and / or the collector structure array is moved to provide spatial movement of the element array relative to the collector structure array.

Images