JP2012238015A - Calibrating pixel elements - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite display device.SOLUTION: A composite display device is disclosed. In some embodiments, the composite display device includes a paddle configured to sweep out an area, a plurality of pixel elements mounted on the paddle, and one or more optical sensors mounted on the paddle and configured to measure luminance values of the plurality of pixel elements. Selectively activating one or more of the plurality of pixel elements while the paddle sweeps the area causes at least a portion of an image to be displayed.

Description

  The present invention relates to pixel element calibration.

  Digital display devices are used to display images or videos that are presented with advertisements or other information. For example, the digital display device can be used as a large outdoor signboard, bulletin board, poster, highway sign, and stadium display device. Digital display devices that use liquid crystal display (LCD) or plasma technologies are limited in size due to the dimensional limitations of the glass panels associated with these technologies. Larger display devices typically include a grid of printed circuit board (PCB) tiles, each package having a packaged light emitting diode (LED) mounted. Because LEDs require space, the resolution of these display devices is relatively coarse. In addition, since each LED corresponds to one pixel in the image, the large display device can be expensive. In addition, complex cooling systems are commonly used to reduce the heat generated by LEDs that can be damaged at high temperatures. As such, there is a need for improved digital display technology.

  Various embodiments of the invention are disclosed in the following detailed description and the accompanying drawings.

1 is a diagram illustrating an embodiment of a composite display device 100 having a single paddle. It is a figure which shows one Embodiment of the paddle used for a composite display apparatus. It is a figure which shows an example of the time pixel (temporal pixel) in a sweep surface. 1 is a diagram illustrating an embodiment of a composite display device 300 having two paddles. FIG. It is a figure which shows the example of the paddle attachment in a composite display apparatus. FIG. 6 is a diagram illustrating an embodiment of a composite display device 410 that uses a mask. FIG. 11 is a diagram illustrating an embodiment of a composite display device 430 that uses a mask. 1 is a block diagram illustrating an embodiment of a system for displaying an image. 1 is a diagram illustrating an embodiment of a composite display device 600 having two paddles. FIG. 3 is a flow diagram illustrating one embodiment of a process for generating a pixel map. It is a figure which shows the example of the paddle arrange | positioned as various arrays. It is a figure which shows the example of the paddle which carries out the movement which cooperated in order to prevent mechanical interference. It is a figure which shows the example of the paddle accompanying the movement which cooperated and prevented the phase in order to prevent mechanical interference. It is a figure which shows an example of the paddle cross section in a composite display apparatus. It is a figure which shows one Embodiment of the paddle of a composite display apparatus. It is a figure which shows one Embodiment of the paddle of a composite display apparatus. It is a figure which shows an example of the pass band of a broadband photodetector. It is a figure which shows an example of the spectrum profile of red LED. It is a figure which shows both the pass band of a broadband photodetector, and the spectrum profile of red LED. It is a figure which shows an example of the spectrum profile of red LED in which the brightness | luminance deteriorated, and the pass band of a broadband photodetector. FIG. 6 illustrates one embodiment of a process for calibrating a pixel element. It is a figure which shows an example of the pass band of a red sensitive light detector. It is a figure which shows both the pass band of a red sensitive photodetector, and the spectrum profile of red LED. It is a figure which shows an example of the spectrum profile of red LED in which the brightness | luminance deteriorated, and the pass band of a red sensitive photodetector. It is a figure which shows an example of the color coordinate shift of red LED, and the pass band of a red sensitive photodetector. It is a figure which shows an example of the spectrum profile of the red LED overdriven, and the pass band of a red sensitive photodetector. It is a figure which shows one Embodiment of the paddle of a composite display apparatus. It is a figure which shows one Embodiment of the paddle of a composite display apparatus. 5 is a flow diagram illustrating one embodiment of a process for calibrating paddle LEDs. It is a figure which shows the pass band of a photodetector. It is a figure which shows the pass band of two photodetectors.

  The invention may be implemented in many ways, including a computer readable medium, such as a process, apparatus, system, material synthesis, computer readable storage medium, or a computer network in which program instructions are sent over an optical or communication link. Can do. In this specification, these implementations, or any other form that may be employed in the present invention, may be referred to as techniques. A component such as a processor or memory that is described to be configured to perform a task includes a general component that is temporarily configured to perform the task at a given time, and the task As well as dedicated components that are manufactured to perform. In general, the order of the steps of disclosed processes may be altered within the scope of the invention.

  A detailed description of one or more embodiments of the invention is provided below along with accompanying figures that illustrate the principles of the invention. While the invention will be described in connection with such embodiments, the invention is not limited to any embodiment. The scope of the invention is limited only by the claims and the invention encompasses numerous alternatives, modifications and equivalents. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. These details are presented for purposes of illustration, and the invention may be practiced according to the claims without some or all of these specific details. For the purpose of clarity, technical material that is known in the technical fields related to the invention has not been described in detail so that the invention is not unnecessarily obscured.

  FIG. 1 illustrates one embodiment of a composite display device 100 having a single paddle. In the illustrated example, the paddle 102 is configured to rotate at one end around the axis of rotation 104 at a given frequency, such as 60 Hz. The paddle 102 sweeps the region 108 during one revolution or paddle cycle. A plurality of pixel elements such as LEDs are mounted on the paddle 102. As used herein, a pixel element refers to any element that can be used to display at least a portion of image information. As used herein, an image or image information may include an image, video, animation, slide show, or any other visual information that can be displayed. Examples of other pixel elements include laser diodes, phosphors, cathode ray tubes, liquid crystals, and any transmissive or emissive light modulator. Although the example herein describes an LED, any suitable pixel element can be used. As described more fully below, in various embodiments, the LEDs can be placed on the paddle 102 in a variety of ways.

  When the paddle 102 sweeps the area 108, one or more LEDs of the paddle are driven at the appropriate time so that a viewer watching the area 108 being swept will perceive the image or a portion thereof. . The image is composed of pixels each having a spatial position. It can be determined which spatial position a particular LED is at a given arbitrary time. As paddle 102 rotates, each LED can be driven appropriately when its position matches the spatial position of a pixel in the image. If the paddle 102 is rotating fast enough, the eye will perceive a continuous image. This is due to the low frequency response of the eye to luminance and color information. The eye captures the color it sees within a certain time window. If several images are shown quickly in quick succession, the eye integrates it into a single continuous image. This low eye temporal sensitivity is called afterimage.

  As such, each LED on the paddle 102 can be used to display a plurality of pixels in the image. A single pixel in the image is mapped to at least one “time pixel” in the display area of the composite display device 100. As described more fully below, a time pixel can be defined by a pixel element on paddle 102 and time (or angular position of the paddle).

  The display area for showing an image or a video can be in any shape. For example, the maximum display area is circular and is the same as the sweep area 108. Within the sweep area 108, a rectangular image or video can be displayed as the illustrated rectangular display area 110.

  FIG. 2A is a diagram showing an embodiment of a paddle used in a composite display device. For example, paddle 202, 302 or 312 (discussed later) may be similar to paddle 102. The paddle 202 is shown to include a plurality of LEDs 206-216 and a rotating shaft 204 about which the paddle 202 rotates. The LEDs 206-216 can be arranged in any suitable manner in various embodiments. In this example, the LEDs 206 to 216 are arranged so as to be aligned along the longitudinal direction of the paddle 202 at equal intervals. These are arranged on the edge of the paddle 202 so that the LED 216 is close to the axis of rotation 204. For this reason, when the paddle 202 rotates, there is no blank portion in the center (around the rotation axis 204). In some embodiments, paddle 202 is a PCB shaped like a paddle. In some embodiments, the paddle 202 has a casing of aluminum, metal or other material for reinforcement.

  FIG. 2B shows an example of temporal pixels in the sweep plane. In this example, each LED on the paddle 222 is associated with an annulus around the axis of rotation (the area between the two circles). Each LED can be driven once per sector (angle interval). Driving the LED can include, for example, turning the LED on for a specified time (eg, associated with a duty cycle), or turning the LED off. Each intersection line of the concentric circle and the sector forms a region corresponding to the time pixel. In this example, each time pixel has an angle of 22.5 degrees, so there will be a total of 16 sectors where the LED can be turned on during that time to display the pixel. Since there are 6 LEDs, there are 6 × 16 = 96 time pixels. In another example, a temporal pixel can have an angle of 1/10 degrees, resulting in a total of 3600 possible angular positions.

  In the example shown, the spacing of the LEDs is uniform along the paddle, so the time pixels are dense toward the center of the display device (near the axis of rotation). Since image pixels are defined based on an orthogonal coordinate system, when an image is placed on a display device, one image pixel may correspond to a plurality of time pixels close to the center of the display device. Conversely, in the most distant portion of the display device, one image pixel may correspond to one or a portion of the time pixel. For example, two or more image pixels may be fitted within a single time pixel. In some embodiments, the display device is at least one time per image pixel at a position furthest away from the center of the display device (e.g., by changing the sector time or number / placement of LEDs on the paddle). Designed to have pixels. As a result, the same resolution level as that of the image is held in the display device. In some embodiments, the sector size is limited by how fast the LED control data can be transferred to the LED driver to drive the LED. In some embodiments, an LED array on the paddle is used that makes the density of temporal pixels more uniform across the display. For example, the LEDs can be placed closer together on the paddle the further away from the axis of rotation.

  FIG. 3 is a diagram illustrating an embodiment of a composite display device 300 having two paddles. In the illustrated example, the paddle 302 is configured to rotate around a rotational axis 304 at a given frequency, such as 60 Hz, at one end. Paddle 302 sweeps region 308 during one revolution or paddle cycle. A plurality of pixel elements such as LEDs are mounted on the paddle 302. The paddle 312 is configured to rotate at one end about a rotational axis 314 at a given frequency, such as 60 Hz. Paddle 312 sweeps region 316 during one revolution or paddle cycle. A plurality of pixel elements such as LEDs are mounted on the paddle 312. The regions 308 and 316 that are swept have overlapping portions 318.

  Use of a plurality of paddles in a composite display device is desirable for manufacturing a larger display device. For each paddle, it is possible to determine in which spatial position a particular LED is at a given time, so that, similar to that described with respect to FIG. 1, any image can be represented by a multiple paddle display. it can. In some embodiments, the overlap portion 318 will pass twice as many LEDs per cycle as the non-overlap portion. As a result, the overlapping portion of the display device may appear to the eye as having high brightness. Thus, in some embodiments, if there is an LED in the overlap, it can be driven for half the time, so that the entire display area appears to have the same brightness. The above and other examples of processing overlapping regions are described more fully below.

  The display area for showing an image or a video can be in any shape. When the sweep areas 308 and 316 are combined, the maximum display area is obtained. A rectangular image or video can be displayed in the illustrated rectangular display area 310.

  When using multiple paddles, there are various ways to ensure that adjacent paddles do not collide with each other. FIG. 4A shows an example of paddle attachment in the composite display device. In these examples, cross-sections of adjacent paddles mounted on the shaft are shown.

  In FIG. 402, two adjacent paddles rotate within each vertically separated sweep plane, thereby ensuring that the paddles do not collide when rotated. This means that the two paddles can rotate at different speeds and do not need to be in phase with each other. If the display resolution is sufficiently lower than the vertical spacing between each sweep surface, the eye cannot detect that the two paddles are rotating on separate sweep surfaces. In this example, the axis is at the center of the paddle. This embodiment is described more fully below.

  In FIG. 404, two paddles rotate in the same sweep plane. In this case, the paddle rotation is adjusted to avoid a collision. For example, each paddle rotates in phase with each other. This further example is described more fully below.

  In the case of two paddles with separate sweep surfaces, light may leak diagonally between the sweep surfaces when viewing the display region 310 from a point that is not perpendicular to the display region 310. This can occur, for example, when a pixel emits unfocused light and so the light is emitted in a range of angles. In some embodiments, a mask is used to block light from one sweep surface from being visible from the other sweep surface. For example, a mask is placed behind paddle 302 and / or paddle 312. The mask can be attached to paddle 302 and / or paddle 312 or can be fixedly attached to paddle 302 and / or paddle 312. In some embodiments, paddle 302 and / or paddle 312 may have a different shape than that shown in FIGS. 3 and 4A, for example for masking purposes. For example, paddle 302 and / or paddle 312 can be shaped to mask the sweep surface of the other paddle.

  FIG. 4B is a diagram illustrating an embodiment of a composite display device 410 that uses a mask. In the illustrated example, the paddle 426 is configured to rotate at one end about a rotational axis 414 at a given frequency, such as 60 Hz. A plurality of pixel elements such as LEDs are mounted on the paddle 426. Paddle 426 sweeps region 416 (thick dashed line) during one revolution or paddle cycle. The paddle 428 is configured to rotate at one end around the rotational axis 420 at a given frequency, such as 60 Hz. Paddle 428 sweeps region 422 (thick dashed line) during one revolution or paddle cycle. A plurality of pixel elements such as LEDs are mounted on the paddle 428.

  In this example, a mask 412 (solid line) is used behind the paddle 426. In this case, the mask 412 has the same shape as the region 416 (ie, a circle). The mask 412 masks light from the pixel elements on the paddle 428 so as not to leak into the sweep region 416. The mask 412 can be attached behind the paddle 426. In some embodiments, the mask 412 is attached to the paddle 426 and rotates about the axis of rotation 414 with the paddle 426. In some embodiments, the mask 412 is attached behind the paddle 426 and secured to the paddle 426. In this example, the mask 418 (solid line) is similarly attached behind the paddle 428.

  In various embodiments, mask 412 and / or mask 418 can be made from a variety of materials and have a variety of colors. For example, masks 412 and 418 can be black and made from plastic.

  The display area for showing an image or a video can be in any shape. When the swept areas 416 and 422 are combined, a maximum display area is obtained. A rectangular image or video can be displayed in the rectangular display area 424 shown.

Regions 416 and 422 partially overlap. As used herein, two elements (eg, sweep region, sweep plane, mask, pixel element) are said to partially overlap if they intersect in an xy projection. In other words, when these regions are projected on the x-y plane (defined by the x and y axes, where the x and y axes are in the plane of the figure), they intersect each other. Regions 416 and 422 do not sweep the same plane (do not have the same z value, where the z-axis is perpendicular to the x-axis and y-axis), but overlap each other in overlapping portion 429. In this example, the mask 412 blocks the sweep region 422 at the overlapping portion 429 or the blocking region 429. The mask 412 blocks the sweep region 429 because it partially overlaps the sweep region 429 and overlies the sweep region 429.

  FIG. 4C is a diagram illustrating one embodiment of a composite display device 430 that uses a mask. In this example, the pixel element is attached to a rotating disk that functions as both a mask and a structure of the pixel element. The disk 432 can be viewed as a circular paddle. In the illustrated example, the disk 432 (solid line) is configured to rotate around a rotational axis 434 at one end at a given frequency, such as 60 Hz. A plurality of pixel elements such as LEDs are mounted on the disk 432. The disk 432 sweeps the region 436 (thick dashed line) during one revolution or one disk period. The disk 438 (solid line) is configured to rotate around a rotational axis 440 at a given frequency, such as 60 Hz, at one end. The disk 438 sweeps the region 442 (thick dashed line) during one revolution or one disk period. A plurality of pixel elements such as LEDs are mounted on the paddle 438.

  In this example, the pixel element can be mounted anywhere on the disks 432 and 438. In some embodiments, the pixel elements are mounted in the same pattern on the disks 432 and 438. In another embodiment, separate patterns are used on each disk. In some embodiments, the density of pixel elements decreases toward the center of each disk, and therefore the density of temporal pixels is more uniform than if the density of pixel elements is the same across the entire disk. In some embodiments, pixel elements are arranged to provide redundancy for temporal pixels (ie, multiple pixels are arranged at the same radius). Having more pixel elements per pixel means that the rotational speed can be reduced. In some embodiments, the pixel elements are arranged such that the temporal pixel resolution is higher.

The disk 432 masks light from the pixel elements on the disk 438 so that it does not leak into the sweep region 436. In various embodiments, the disks 432 and / or 438 can be made from various materials and have various colors. For example, disks 432 and 438 can be black printed circuit boards on which LEDs are mounted.

  The display area for showing an image or a video can be in any shape. When the swept areas 436 and 442 are combined, a maximum display area is obtained. A rectangular image or video can be displayed in the illustrated rectangular display area 444.

  Regions 436 and 442 overlap at overlap 439. In this example, the disk 432 blocks the sweep region 442 at the overlap portion 439 or the blocking region 439.

  In some embodiments, the pixel element is configured not to be driven when it is shut off. For example, a pixel element mounted on the disk 438 is configured not to be driven when it is blocked (eg, overlaps the blocking area 439). In some embodiments, the pixel element is configured not to be driven in the portion of the blocking region. For example, an area within a certain distance from the edge of the blocking area 439 is configured not to be driven. This may be desirable when the viewer is on the left or right side of the center of the display area and can see the edge portion of the blocking area.

  FIG. 5 is a block diagram illustrating an embodiment of a system for displaying an image. In the illustrated example, the paddle panel 502 is a structure comprising one or more paddles. As described more fully below, the paddle panel 502 can be paddles of various sizes, lengths and widths, paddles rotating around midpoints or endpoints, in the same sweep plane or in separate sweep planes. Multiple paddles can be included, which can include rotating paddles, paddles rotating in phase with each other or out of phase, paddles having multiple arms, and paddles having other shapes. The paddle panel 502 can include all the same paddles, or a variety of different paddles. The paddles can be arranged as a grid or any other arrangement. In some embodiments, the panel includes an angle detector 506, which is used to detect an angle associated with one or more paddles. In some embodiments, there is an angle detector for each paddle on the paddle panel 502. For example, a photodetector can be mounted near a paddle to detect its current angle.

  The LED control module 504 is configured to optionally receive current angle information from the angle detector 506 (e.g., angle (s) or information associated with the angle (s)). The The LED control module 504 uses the current angle to determine LED control data to send to the paddle panel 502. The LED control data indicates which LED should be driven at that time (sector). In some embodiments, the LED control module 504 uses the pixel map 508 to determine LED control data. In some embodiments, the LED control module 504 takes an angle as an input and outputs which LEDs on the paddle for that sector should be driven for a particular image. In some embodiments, the angle is sent from the angle detector 506 to the LED control module 504 on a sector-by-sector basis (eg, just before the paddle reaches the sector). In some embodiments, LED control signals are sent from the LED control module 504 to the paddle panel 502 for each sector.

  In some embodiments, the pixel map 508 is implemented using a look-up table, as described fully below. Different look-up tables are used for different images. The pixel map 508 is described more fully below.

In some embodiments, the angle detector 506 need not be used to read the angle. Since the angular velocity of the paddle and the initial angle of the paddle (at that angular velocity) can be pre-defined, it is possible to calculate which angle the paddle is at any given time. In other words, the angle can be determined based on time. For example, when the angular velocity is ω, the angular position after time t is θ _initial + ωt. Here, θ _initial is an initial angle when the paddle is rotating in a steady state. As such, the LED control module can sequentially output LED control data as a function of time (eg, using a clock) rather than using the angle measurement output from the angle detector 506. For example, a table of time (eg, clock period) versus LED control data can be created.

  In some embodiments, when the paddle starts up from a stopped state, the paddle increases in speed to the steady state angular velocity via the startup sequence. When that angular velocity is reached, the initial angle of the paddle is estimated to calculate what angle the paddle is at any point in time (and to determine at what point in the series of LED control data to start) .

  In some embodiments, the angle detector 506 is used periodically to make adjustments as needed. For example, if the angle drifts, the output stream of LED control data can be shifted. In some embodiments, if the angular velocity drifts, a mechanical adjustment is made to adjust the velocity.

  FIG. 6A is a diagram illustrating an embodiment of a composite display device 600 having two paddles. In the illustrated example, a polar coordinate system is shown on each of the regions 608 and 616, and the origin is placed on the rotation axes 604 and 614, respectively. In some implementations, the position of each LED on paddles 602 and 612 is recorded in polar coordinates. The distance from the origin to the LED is radius r. The paddle angle is θ. For example, if the paddle 602 is in the 3 o'clock position, each LED on the paddle 602 is at 0 degrees. When paddle 602 is at the 12 o'clock position, each LED on paddle 602 is at 90 degrees. In some embodiments, an angle detector is used to detect the current angle of each paddle. In some embodiments, a time pixel is defined by P, r and θ, where P is a paddle identifier and (r, θ) is the polar coordinates of the LED.

  An orthogonal coordinate system is shown above the image 610 to be displayed. In this example, the origin is located in the center of the image 610, but may be located anywhere depending on the implementation. In some embodiments, a pixel map 508 is created by mapping each pixel in the image 610 to one or more temporal pixels in the display areas 608 and 616. The mapping can be implemented in different ways in different embodiments.

  FIG. 6B is a flow diagram illustrating one embodiment of a process for generating a pixel map. For example, the pixel map 508 can be created using this process. At 622, image pixels for temporal pixel mapping are obtained. In some embodiments, image 610 (that pixel corresponding to the resolution of the image (xx) over regions 608 and 616 (having a polar lattice of those two time pixels (r, θ), see for example FIG. 2B)). , Y) with the orthogonal lattice) is superimposed. For each image pixel (x, y), it is determined which time pixel is in that image pixel. The following is an example of a pixel map.

  As described above, one image pixel can be mapped to multiple time pixels as shown in the second row. In some embodiments, indicators corresponding to LEDs are used instead of r. In some embodiments, image pixels for temporal pixel mapping are precomputed for various image sizes and resolutions (eg, commonly used).

  At 624, the intensity f is read for each image pixel based on the image to be displayed. In some embodiments, f indicates whether the LED should be on (eg, 1) or off (eg, 0). For example, in a black and white image (no grayscale), black pixels map to f = 1 and white pixels map to f = 0. In some embodiments, f may have a fractional value. In some embodiments, f is implemented using a duty cycle management approach. For example, if f is 0, the LED is not driven during that sector time. If f is 1, the LED is driven for the entire sector time. If f is 0.5, the LED is driven for half the sector time. In some embodiments, f can be used to display a grayscale image. For example, if there are 256 gray levels in the image, a pixel with gray level 128 (half luminance) will be f = 0.5. In some embodiments, f is implemented by adjusting the current to the LED (ie, pulse height modulation), rather than implementing f using a duty cycle (ie, pulse width modulation).

  For example, after f is read, the table looks like this:

  At 626, optional pixel map processing is performed. This may include compensating for overlap, balancing the brightness at the center (ie, the high density of temporal pixels), balancing the usage frequency of the LEDs, and the like. For example, if the LED is in the overlap region (and / or the boundary of the overlap region), its duty cycle can be reduced. For example, when the LED is in the overlap region 318 in the composite display device 300, its duty cycle is halved. In some embodiments, multiple LEDs corresponding to a single image pixel are in one sector time, but in this case, fewer than all LEDs can be driven (i.e., some of the duty cycle Can be set to 0). In some embodiments, the LEDs can be driven alternately (eg, every N periods, where N is an integer) so that one LED does not break faster than the other, eg, to balance usage. In some embodiments, the closer the LED is to the center (higher density of time pixels), the smaller its duty cycle.

  For example, after luminance balance, the pixel map can be as follows:

  As shown in the table, the second time pixel in the second row was deleted to balance the luminance across the pixels. This could also be achieved by halving the strength to f2 / 2. As another alternative, temporal pixels (b4, b5, b6) and (b7, b8, b9) can be turned on alternately between each period. In some embodiments, this can be displayed in a pixel map. Pixel maps can be implemented in different ways using different data structures in different implementations.

  For example, in FIG. 5, the LED control module 504 uses temporal pixel information (P, r, θ and f) from the pixel map. The LED control module 504 takes θ as an input and outputs LED control data P, r, and f. The paddle panel 502 uses this LED control data to drive the LED for that sector time. In some embodiments, there is an LED driver for each paddle that uses LED control data to determine which LEDs to turn on for each sector time, if any. .

  Arbitrary image (including video) data can be input to the LED control module 504. In various embodiments, one or more 622, 624, and 626 can be calculated in raw or real time, i.e., immediately before displaying the image. This is effective for live broadcasting of images such as live video of a studio. For example, in some embodiments, 622 is pre-calculated and 624 is calculated live or in real time. In some embodiments, 626 can be performed before 622 by appropriately modifying the pixel map. In some embodiments, 622, 624 and 626 are all precomputed. For example, since the advertisement image is usually known in advance, it can be pre-calculated.

  The process of FIG. 6B may be performed in various ways in various embodiments. Another example of how 622 can be performed is as follows. Polar coordinates are calculated for each image pixel (x, y). For example, the image pixel (of its center) is converted to polar coordinates for the sweep region where it partially overlaps (if the image pixel partially overlaps the overlapping sweep region, there may be multiple sets of polar coordinates) . The calculated polar coordinates are rounded to the nearest time pixel. For example, the time pixel closest to the calculated polar coordinate is selected. (If there are multiple sets of polar coordinates, the time pixel closest to the calculated polar coordinate is selected.) In this way, each image pixel is mapped to at most one time pixel. This may be desirable because it maintains a uniform density of temporal pixels driven within the display area (ie, the density of temporal pixels driven near the axis of rotation does not become higher than the edge). For example, instead of the pixel map shown in Table 1, the following pixel map can be obtained.

  In some cases, this rounding technique may be used to map two image pixels to the same time pixel. In this case, various techniques can be used at 626, including, for example, averaging the intensity of two rectangular pixels and assigning the average value to one time pixel, first and second between periods. This includes altering the rectangular pixel intensity, remapping one of the image pixels to the nearest time pixel, and so on.

  FIG. 7 shows examples of paddles arranged as various arrays. For example, any of these arrays can include a paddle panel 502. Any number of paddles can be combined in the array to create a display area of any size and shape.

  Arrangement 702 shows eight circular sweep regions, each corresponding to eight paddles of the same size. The sweep regions partially overlap as shown. In addition, a rectangular display area is shown above each sweep area. For example, the largest rectangular display area in this arrangement includes a combination of all of the illustrated rectangular display areas. In order to ensure that there is no gap in the maximum display area, the spacing between the rotation axes is (√2) R, where R is the radius of one circular sweep area. The axes are spaced so that the periphery of one sweep region does not overlap any rotation axis, otherwise interference will occur. One or more images can be displayed using any combination of these sweep areas and rectangular display areas.

  In some embodiments, the eight paddles are in the same sweep plane. In some embodiments, the eight paddles are in separate sweep planes. It may be desirable to minimize the number of sweep surfaces used. For example, the same sweep surface can be swept with every other paddle. For example, sweep regions 710, 714, 722, and 726 can be in the same sweep plane, and sweep regions 712, 716, 720, and 724 can be in another sweep plane.

  In some configurations, each sweep region (eg, sweep regions 710 and 722) partially overlap each other. In some configurations, each sweep region touches each other at one point (eg, sweep regions 710 and 722 can be moved away from each other so that they touch only one point). In some configurations, the sweep regions do not overlap each other (eg, there is a gap between the sweep regions 710 and 722), which is acceptable if the desired resolution of the display device is sufficiently low.

  Arrangement 704 shows 10 circular sweep regions corresponding to 10 paddles. Each sweep region partially overlaps as shown. In addition, a rectangular display area is shown above each sweep area. For example, three rectangular display areas can be used, one in each row of sweep areas, to display, for example, three separate advertising images. One or more images can be displayed using any combination of these sweep areas and rectangular display areas.

  Arrangement 706 shows seven circular sweep regions corresponding to seven paddles. Each sweep region partially overlaps as shown. In addition, a rectangular display area is shown above each sweep area. In this example, each paddle has a different size, so the sweep area has a different size. One or more images can be displayed using any combination of these sweep areas and rectangular display areas. For example, all sweep areas can be used as a single display area for non-rectangular images such as snake cutouts.

  FIG. 8 shows an example of a paddle that moves in phase in tandem to prevent mechanical interference. In this example, an array of 8 paddles is shown at 3 time points. The eight paddles are configured to move in phase with each other. That is, at each point in time, each paddle is oriented in the same direction (or associated with the same angle when using the polar coordinate system depicted in FIG. 6A).

  FIG. 9 shows an example of a paddle that moves in phase with each other to prevent mechanical interference. In this example, an array of four paddles is shown at three time points. The four paddles are configured to move out of phase with each other. That is, at each point in time, at least one paddle is not oriented in the same direction as the other paddles (or at least one paddle is associated with the same angle when using the polar coordinate system depicted in FIG. 6A). In this case, the paddles move out of phase, but their phase difference (angle difference) is such that the paddles do not mechanically interfere with each other.

  The display device system described in this specification has a built-in natural cooling system. Since the paddle is rotating, heat naturally dissipates from the paddle. The LED is cooled more as it is farther from the rotation axis. In some embodiments, this type of cooling is at least 10 times more effective than systems where LED tiles are fixed, as well as systems where an external cooling system is used that blows air over the LED tiles using a fan. There is. Furthermore, significant cost reductions are realized by not using an external cooling system.

  In each example herein, the image to be displayed is formed with pixels associated with orthogonal coordinates, and the display area is associated with temporal pixels described in polar coordinates, but the techniques herein are: It can be used with any coordinate system for the image area or display area.

  Although the rotational movement of the paddle is described herein, any other type of paddle movement can also be used. For example, the paddle can be configured to move laterally (if the LEDs are aligned, a rectangular sweep region results). The paddle can be configured to rotate and move laterally simultaneously (resulting in an oval sweep region). The paddle can have an arm configured to expand and contract at several angles, for example to create a more rectangular sweep region. Since the movement is known, the pixel map can be determined and the techniques described herein can be applied.

  FIG. 10 is a diagram showing an example of a paddle cross section in the composite display device. In this example, it is shown to include a paddle 1002, a shaft 1004, an optical fiber 1006, an optical camera 1012, and an optical data transmitter 1010. Paddle 1002 is attached to shaft 1004. The shaft 1004 is hollowed out (ie, hollow), and the optical fiber 1006 passes through the center thereof. Base 1008 of optical fiber 1006 receives data via optical data transmitter 1010. Data is sent over optical fiber 1006 and is sent 1016 to a photodetector (not shown) on paddle 1002. The photodetector provides the data to one or more LED drivers that are used to drive one or more LEDs on the paddle 1002. In some embodiments, LED control data received from the LED control module 504 is thus sent to the LED driver.

  In some embodiments, the base of shaft 1004 has appropriate markings 1014 that are read by optical camera 1012 to determine the current angular position of paddle 1002. In some embodiments, the optical camera 1012 is used in conjunction with the angle detector 506 to output angle information that is provided to the LED control module 504 shown in FIG.

  The performance of the pixel elements constituting the composite display device may deteriorate as it ages. Degradation of a pixel element is manifested in two forms: a decrease in intensity or luminance of the pixel element over time and / or a color coordinate shift over time of the spectral profile of the pixel element. In some cases, a decrease in luminance (ie, the pixel element becomes dark) becomes the first phenomenon of deterioration, and a shift in the spectrum of the pixel element becomes a second phenomenon. As described further below, the composite display device paddles can be periodically calibrated to correct at least a portion of the composite display device pixel elements and / or improve performance degradation. One or more components may be included to help detect degradation of the.

  In some embodiments, one or more light sensors (e.g., photodetectors, photodiodes, etc.) are mounted on each paddle of the composite display, and the intensity or brightness of the light emitted by the pixel elements on the paddle Used to measure. Although the examples herein can describe a photodetector, any suitable optical sensor can be used. The type of photodetector mounted on the paddle depends on the type of pixel element degradation that it is desired to detect and correct. For example, if it is desired to detect only the first phenomenon of pixel element degradation (ie, a decrease in brightness), a broadband photodetector may be sufficient. However, if it is desired to also detect color coordinate shifts, further red, green and / or blue sensitive photodetectors may be required. As will be further described below, in various embodiments, a portion of the light emitted by the pixel element is reflected by a structure used to protect the front surface of the composite display device, and at a corresponding photodetector. A portion of the light that may be received or emitted by the pixel element may be focused with a custom lenslet attached to the pixel element in the direction of the corresponding photodetector. A photodetector mounted on the paddle can be used initially to measure the reference luminance value when calibrating the pixel element during manufacture or installation. In some embodiments, other pixel elements (eg, nearby pixel elements or all pixel elements on the paddle) are turned off while determining a reference luminance value for one pixel element. During subsequent on-site calibration, the photodetector can be used to measure the current luminance value of the pixel element. The current brightness value of a pixel element can be compared to an associated reference brightness value measured when the pixel element was first calibrated. The current for driving the pixel element can be appropriately adjusted during field calibration so as to restore the reference value when the luminance value of the pixel element is lowered. The current luminance value of the pixel element can also be used to detect a color shift. A color shift, for example, overdrives one or more pixel elements associated with insufficient colors and underlines one or more pixel elements associated with colors that are too large to rebalance each color. It can be corrected by driving.

  FIG. 11A shows one embodiment of a paddle of a composite display device. The paddle 1100 includes a PCB disk that rotates about a rotation axis 1102. The pixel elements are mounted on the paddle 1100 in the radial direction, and are depicted as small squares in the illustrated example. The photodetector is also mounted on the paddle 1100 and is depicted as a small circle in the illustrated example. In various embodiments, each photodetector can be associated with an intensity or brightness measurement of any number of pixel elements. For example, in some embodiments, each photodetector mounted on a paddle can be associated with a set of 5-10 pixel elements that are radially adjacent. In the example of FIG. 11A, each photodetector is associated with a set of five pixel elements adjacent in the radial direction. For example, the photodetector 1104 is associated with measuring the brightness of each pixel element 1106. A portion of the light emitted by each pixel element of the set 1106 is reflected toward and / or received by the photodetector 1104. The intensity or brightness of each pixel element of the set 1106 measured by the photodetector 1104 is determined, at least in part, by the distance and / or angle of the pixel element from the photodetector 1104 and is located far away The pixel element has a low measurement intensity. Thus, if the pixel elements of the paddle 1100 are calibrated at the time of manufacture, the reference luminance value of each pixel element of the set 1106 measured by the associated photodetector 1104 is the distance of the pixel element from the photodetector and / or May vary based on angle. If it is desired to detect and correct only the decrease in brightness of the pixel element, the photodetector can include a broadband photodetector. For example, when the pixel element includes a white LED, the luminance of the LED decreases at least initially due to the deterioration of the LED. In such cases, the brightness value of the LED can be measured periodically using a broadband photodetector, and if it is found that an LED has a brightness lower than its reference value, supply it to that LED. The brightness of the LED can be increased appropriately to return the LED brightness to its reference value. In some embodiments, the pixel elements of the paddle 1100 can include color LEDs, ie red, green and / or blue LEDs. FIG. 11B shows an embodiment where each array of pixel elements of the paddle 1100 includes a red (R), green (G), or blue (B) LED. In such cases, if it is desired to detect and correct only for the decrease in brightness, a broadband photodetector can be used as well.

  FIG. 12A shows an example of the passband of a broadband photodetector that is ideally and uniformly sensitive (ie, detectable) to the brightness of all wavelengths of light. FIG. 12B shows an example of a spectrum profile of a red LED. As shown, this profile is centered around a wavelength around 635 nm. FIG. 12C shows both the passband of the broadband photodetector of FIG. 12A and the spectral profile of the red LED of FIG. 12B. In some embodiments, the brightness of the red LED is determined by the shaded area of FIG. 12C, ie, the portion of the spectral profile of the red LED that is captured by the photodetector. FIG. 12D shows an example of the spectral profile of a red LED with degraded brightness and the passband of a broadband photodetector. As shown, the photodetector of FIG. 12D captures a small area compared to the area of FIG. 12C. Such a decrease in brightness can be corrected by increasing the current driving the LED so that the brightness of the LED recovers to its reference value, eg, the value shown in FIGS. 12B and 12C.

  FIG. 13 illustrates one embodiment of a process for configuring a pixel element. In some embodiments, the pixel element 1300 is used to compensate for pixel element brightness degradation caused by, for example, aging of the pixel element. Process 1300 begins at 1302, where the current luminance value of a particular pixel element is determined. For example, the current luminance value of a pixel element can be determined by an intensity value measured by a photodetector associated with that pixel element. In 1304, compare the current luminance value of the pixel element determined in 1302 with the reference luminance value of that pixel element determined and stored during the initial calibration of the associated composite display device, for example during manufacture or installation. To do. At 1306, it is determined whether the current luminance value of the pixel element is reduced compared to its reference value. If it is determined in 1306 that the current luminance value of the image pixel has not decreased compared to the reference value, calibration for correcting the decrease in luminance is unnecessary, and the process 1300 ends. If it is determined in 1306 that the current brightness value of the image pixel is lower than its reference value (i.e., the current brightness value is lower than the reference value, for example by a certain amount), then The current for driving the pixel element is increased to return the current luminance value of the pixel element to its reference value, and then the process 1300 ends. In some embodiments, the process 1300 is used for each of at least a subset of the pixel elements of the display device during calibration.

  As described above, a decrease in luminance, that is, a darker pixel element, can be one result of performance degradation. In some cases, color coordinate shifts, including shifts in peak wavelengths emitted by pixel elements, can be another consequence of performance degradation. If it is desired to detect and correct only the decrease in brightness or brightness of the pixel element, a broadband photodetector as described above may be sufficient. In some embodiments, it is desirable to detect a change in chromaticity of a pixel element. For example, if the composite display device includes a color LED, a color coordinate shift can occur, for example, as the LED ages.

  In some embodiments, the composite display device comprises color pixel elements such as red, green and blue LEDs. In such cases, red-sensitive, green-sensitive, and blue-sensitive photodetectors can be used to help detect the color shift of the corresponding color LED. For example, a red sensitive light detector can be used to measure the intensity or brightness of a red LED. In order to detect red light and filter out other colors, the passband of the red sensitive photodetector covers the wavelength associated with the red LED. FIG. 14A shows an example of the passband of a red sensitive photodetector. FIG. 14B shows both the passband of the red sensitive photodetector of FIG. 14A and the spectral profile of the red LED of FIG. 12B. In some embodiments, the brightness of the red LED is determined by the shaded area of FIG. 14B, ie, the portion of the spectral profile of the red LED captured by the photodetector. FIG. 14C shows an example of the spectral profile of a red LED with degraded brightness and the passband of a red sensitive photodetector. As shown, the photodetector of FIG. 14C captures a small area compared to the area of FIG. 14B. The reduction in brightness detected by the red sensitive photodetector of FIG. 14C can be detected in the same manner using the broadband photodetector described above with respect to FIG. 12D. FIG. 14D is a diagram showing an example of the color coordinate shift of the red LED and the passband of the red-sensitive photodetector. As shown in the figure, the peak wavelength of the red LED drifts from 635 nm to 620 nm, that is, toward the green side. As with FIG. 14C, the red sensitive photodetector of FIG. 14D captures a small area compared to the area of FIG. 14B. However, the color coordinate shift of FIG. 14D cannot be detected using only a broadband photodetector. This is because, due to the all-pass characteristics of the broadband photodetector, a region similar to that of FIG. 12C is captured even though the spectrum is shifted.

  Assuming that the shaded area in FIG. 14C and the shaded area in FIG. 14D are equivalent, the same luminance value is detected by the red-sensitive photodetector in both cases. The luminance value detected by the red sensitive light detector can be compared with a reference value determined during manufacture or during installation, so that a decrease in luminance can be identified. The low luminance measurement in the case of Fig. 14C is obtained as a result of the darker red LED, and the low luminance measurement in the case of Fig. 14D is as a result of the peak wavelength shift of the red LED and also red sensitive light detection. The result is that the instrument captures only the end of the spectrum of the red LED. The specified decrease in brightness can be corrected so that the brightness of the LED can be restored to its reference value by increasing the current driving the LED. In the case of FIG. 14C, by increasing the driving current of the red LED until the reference luminance value is measured, the luminance of the red LED is restored to the reference value shown in FIG. 14B, for example. In the case of Figure 14D, if the red LED drive current is increased until the reference brightness value is measured, the red-sensitive photodetector will only capture the end of the red LED spectrum due to the color coordinate shift of the red LED. The red LED will be significantly overdriven as shown in FIG. 14E.

  In some embodiments, red sensitive, green sensitive and blue sensitive photodetectors are included in the color composite display to help calibrate the red, green and blue LEDs, respectively. For color composite displays with red, green and blue LEDs, overdriving one or more LEDs may shift the hue or chromaticity of white light, which is specific to the display By simultaneously driving red, green and blue LEDs associated with the display of a time pixel (and / or a set or ring of time pixels). In such cases, white may no longer appear white. For example, in a composite display that includes red, green, and blue LEDs for each time pixel, the red LED drifts toward green as shown in Figure 14E, and the blue and green LEDs need to be adjusted. If not, and therefore not adjusted, the white color (displayed by driving all three color LEDs) will be slightly greenish. Thus, in such cases, it may be necessary to identify the color coordinate shift of a particular color LED and / or to identify a white chromaticity shift. Each of the red-sensitive, green-sensitive, and blue-sensitive photodetectors only helps to determine the change in brightness (e.g., decrease), the change in brightness caused by the change in brightness (e.g., the situation in Figure 14C), and the LED peak. A change in luminance caused by the wavelength shift (for example, the situation in FIG. 14D) cannot be distinguished. In some embodiments, in addition to individual color photodetectors, broadband or white sensitive photodetectors are also used. When one or more color LEDs are overdriven, the brightness of white is much higher than the reference value measured and recorded during initial calibration of the display device, for example during manufacture or installation. In such cases, the current of each color LED adjusted during the calibration process is to identify which color LED (s) are responsible for the increase in white brightness from its reference value. It is possible to individually adjust the increase / decrease while measuring the brightness of white.

  One or more appropriate measures can be taken to restore white chromaticity and / or white brightness to its reference value. In some embodiments, overdriving the missing colors while underdriving the excess colors eliminates the biasing or tinting of the white towards a particular color and / or white Is restored to its reference value. In the described example of a red LED drifting towards the green, for example, the green LED can be underdriven to balance the red LED overdrive. In some embodiments, the color map of the display device can be redefined globally or locally to accommodate changes in the wavelengths of the three primary colors over time. Initially, when a pixel element of a particular source image is mapped to a temporal pixel, a color mapping is defined that maps each color of the source image to an available color space of the display device. If one or more color coordinate shifts are found to occur during the calibration process, in some embodiments, the display is for a color space that corresponds to the smallest color gamut available on the display for a time pixel. The entire device color mapping can be redefined. In some cases, such global color mapping is not necessary, and it may be sufficient to locally redefine the color mapping of the temporal pixels displayed by the color-shifted LED. Such local remapping may suffice because it is difficult for the eye to perceive slight color changes. For example, the eye perceives the difference between a red time pixel displayed by a red LED having a peak wavelength of 635 nm and a red time pixel displayed by a red LED having a peak wavelength of 620 nm, especially at each time. This can be difficult if the area associated with the pixel is very small.

  FIG. 15 shows an embodiment of a paddle of a composite display device. The paddle 1500 is configured to rotate around the rotational axis 1502 to sweep a circular sweep region. For example, paddle 1500 is similar to paddle 102 of FIG. 1, paddle 222 of FIG. 2B, paddles 302 and 312 of FIG. 3, and / or paddles 426 and 428 of FIG. 4B. Alternating red (R), green (G) and blue (B) LEDs are mounted along the length of the paddle 1500 and are depicted as small squares in the illustrated example. Each row of red, green and blue LEDs, such as the top row 1504, at a given radius from the axis of rotation 1502, is associated with a display of a ring of time pixels associated with that radius. Red-sensitive (R), green-sensitive (G), blue-sensitive (B), and broadband and / or white-sensitive (W) photodetectors are also mounted on the paddle 1500 and are depicted as small circles in the example shown. It is. In the paddle configuration of FIG. 15, calibration is performed on each row of LEDs. In various embodiments, each photodetector can be associated with any number of LED intensity or brightness measurements. In the example of FIG. 15, each color sensitive photodetector is associated with a set of five LEDs of the corresponding color, and each broadband photodetector is associated with five rows of LEDs. For example, the photodetector set 1506 is associated with an LED row 1508. Each color sensitive light detector is associated with a measurement of the brightness of the corresponding color LED. For example, a set 1506 of red sensitive photodetectors is associated with measuring the brightness of each red LED in row 1508. Broadband or white sensitive photodetectors are associated with the measurement of white brightness when, for example, all three color LEDs in a particular row are driven simultaneously. For example, broadband photodetectors in set 1506 are associated with a measurement of brightness when all LEDs in a particular row are driven, such as row 1504 of row 1508. A portion of the light emitted by each LED is reflected towards and / or received by the corresponding photodetector. The LED intensity or luminance value measured by the corresponding color sensitive light detector, as well as the white intensity value or luminance value measured for the column by the associated white sensitive light detector, is at least partially Depends on LED distance and / or angle from detector. Thus, when the paddle 1500 LEDs are first calibrated at the time of manufacture or installation, different reference brightness values may be measured for each LED, and different reference white brightness values may be measured for each column. This reference value is compared with the measured value during subsequent calibration, for example in the field.

  FIG. 16 shows an embodiment of a paddle of a composite display device. The paddle 1600 includes a PCB disk configured to rotate about a rotation axis 1602. For example, paddle 1600 is similar to paddles 432 and 438 in FIG. 4C or paddle 1100 in FIG. 11B. An array of alternating red (R), green (G) and blue (B) LEDs are mounted along the radius of the paddle 1600, and in the illustrated example, the LEDs are depicted as small squares. In some embodiments, the LED at the rotational axis 1602 of the center of the paddle 1600 includes a tri-color RGB LED. An LED at a particular radius from the axis of rotation 1602, such as an LED that intersects the ring 1604, is associated with an indication of the ring of time elements associated with that radius. In the example shown, each ring of LEDs includes two LEDs of each primary color. Red-sensitive (R), green-sensitive (G), blue-sensitive (B), and broadband or white-sensitive (W) photodetectors are also mounted on the paddle 1600 and are depicted in small circles in the example shown. Yes. In the paddle configuration of FIG. 16, calibration is performed for each ring of LEDs, such as ring 1604. In various embodiments, each photodetector can be associated with any number of LED intensity or brightness measurements. In the example of FIG. 16, each color sensitive photodetector is associated with a set of four or five adjacent LEDs in the radial direction of the corresponding color, and each broadband photodetector is associated with seven rings of LEDs. Associated. In the illustrated example, a color sensitive photodetector is mounted near the corresponding color LED array, and a broadband photodetector is mounted between the LED arrays. In some embodiments, the broadband photodetector is associated with a measurement of white brightness when all LEDs of a particular ring are driven simultaneously. Multiple broadband photodetectors associated with a particular ring can be used to determine the white brightness of that ring. In some cases, the average luminance value measured by a plurality of broadband photodetectors can be used to determine the white luminance of a ring. The average of these multiple luminance readings is based on the configuration of the LED on the paddle, such as the paddle 1600, and the broadband photodetector, so that each individual broadband photodetector has one or more color luminance readings. It may be necessary because it may be biased. For example, red-green, green-blue, or blue-red bias can occur at each reading of the paddle 1600 broadband photodetector. Thus, to obtain the white brightness of the ring in paddle 1600, the brightness readings from two or more broadband photodetectors associated with that ring may be averaged. A portion of the light emitted by each LED is reflected towards and / or received by the corresponding photodetector. The LED intensity or luminance value measured by the corresponding color sensitive light detector, as well as the white intensity value or luminance value measured for that ring by the associated white sensitive light detector, is at least partially Depends on LED distance and / or angle from detector. Thus, when the paddle 1600 LEDs are first calibrated at the time of manufacture or installation, different reference brightness values may be measured for each LED, and different reference white brightness values may be measured for each ring. This reference value is compared with the measured value during subsequent calibration, for example in the field.

  FIG. 17 illustrates one embodiment of a process for calibrating paddle LEDs. In some embodiments, the process 1700 is used to correct for LED brightness drop and / or color coordinate shift that may occur, for example, due to LED aging. In some embodiments, process 1700 is used to calibrate the LEDs associated with the display of each ring of time pixels of the composite display. For example, the process 1700 can be used to calibrate the LEDs in each column, such as row 1504 in FIG. 15, or the LEDs in each ring, such as ring 1604 in FIG. The process 1700 begins at 1702, where the brightness of each LED associated with the display of a particular ring of time pixels is restored to its reference value as needed (ie, if it has decreased). In some embodiments, process 1300 of FIG. 13 is used at 1702 to restore LED brightness. The brightness of the color LED is determined using an associated color sensitive photodetector. At 1704, all LEDs associated with the time pixel ring display are driven. At 1706, the current white brightness for this ring is determined. White brightness is determined using one or more broadband or white sensitive photodetectors. In some cases, the brightness of white is determined by averaging the brightness readings of two or more broadband photodetectors. In 1708, it is determined whether or not the current white brightness determined in 1706 is higher than the white reference brightness value, for example, by a specified amount. The white reference luminance is determined and stored during initial calibration of the associated display device, for example during manufacture or installation. If it is determined at 1708 that the current white brightness is not higher (eg, by a specified amount) than its reference value, the process 1700 ends. In some such cases, it may be considered that no substantial color coordinate shift has occurred. If it is determined in 1708 that the current white brightness is higher (eg, by a specified amount) than its reference value, the process 1700 proceeds to 1710. At 1710, while measuring the current white brightness, the current delivered to each LED whose brightness was restored at 1702 is individually modulated (eg up and down) to overdrive to compensate for its color coordinate shift LED (s) being identified are determined, i.e., the LED (s) that cause the white brightness to exceed its reference value are identified. At 1712, one or more appropriate actions are taken to restore white chromaticity and / or white brightness to its reference value, after which process 1700 ends. For example, the color to which another color LED has shifted can be underdriven to balance the color. In some cases, the color map of the display device can be redefined globally for the entire display device or locally for the LEDs associated with the ring, based on the smallest available color gamut.

  Process 1700 of FIG. 17 is an example of a calibration technique. In other embodiments, any other suitable calibration technique and / or combination of techniques may be used. For example, another calibration technique that can be used is to measure the current LED brightness value using a broadband photodetector and compare that value to a reference broadband brightness value, as well as a corresponding color-sensitive photodetector. Using to measure the brightness value of the current LED and comparing that value with the reference color sensitive brightness value. The current luminance value measured by the broadband photodetector exceeds the specified amount and is smaller than the reference broadband luminance value, and the current luminance value measured by the corresponding color sensitive photodetector is smaller than the reference color sensitive luminance value. In some embodiments, it can be concluded that the brightness of the LED has decreased, and the current delivered to the LED can be appropriately adjusted to restore brightness. The current luminance value measured by the broadband photodetector is approximately the same as the reference broadband luminance value, or smaller than the reference broadband luminance value but less than the specified amount, and the current luminance value measured by the corresponding color sensitive photodetector In some embodiments, it can be concluded that the hue of the LED has shifted, and one or more actions to adjust this color shift may be taken. Can be taken. If the current luminance value measured by the broadband photodetector is approximately the same as the reference broadband luminance value and the current luminance value measured by the corresponding color sensitive photodetector is approximately the same as the reference color sensitive luminance value, In such an embodiment, it can be concluded that the LED has not been significantly degraded and no adjustment is required.

  The calibration techniques described herein can be used to automatically calibrate the pixel elements of the composite display device. A photodetector mounted on the composite display paddle allows the current or real-time luminance value of the pixel element to be measured at any given time. As described above, in some embodiments, the pixel elements of the composite display device are initially calibrated at the time of manufacture and / or installation to obtain a reference luminance value. The pixel element can then be calibrated in the field as needed. For example, the pixel element can be calibrated periodically. In some embodiments, during calibration of the pixel elements, the composite display device is hidden from content. Hiding the content during calibration may be necessary if the paddle needs to be in place during calibration. If the content needs to be hidden during calibration, the calibration can be performed, for example, at midnight or any other time when it is allowed to hide the content. The advantage of performing the calibration at midnight is that the sunlight, which can change with time and weather, does not affect the measurement. In some embodiments, calibration can be performed while the composite display device is displaying content. Calibration can be performed on one pixel element at a time or in parallel on a few pixel elements at a time, so calibration is performed while other pixel elements on the display device are displaying content can do. In some embodiments, the frequency domain is used to distinguish between signals associated with calibration and signals associated with the display of content. For example, a calibrated pixel element can be operated at a different frequency than a pixel element displaying content. In such a case, the photodetector associated with the pixel element being calibrated is configured to operate at the same frequency as the pixel element. In one embodiment, the calibrated pixel element is operated at a high frequency, and the associated photodetector is operated while the pixel element displaying the content is operated at a relatively low frequency, That is, it is configured to detect such a high-frequency signal. Calibrating in the frequency domain also allows light emitted by the pixel element being calibrated to be distinguished from ambient light in the environment of the composite display device. In some embodiments, each pixel element that is calibrated at a given time, and its associated photodetector, operates at a particular frequency, for example when multiple pixel elements are calibrated in parallel. And so the light detector emits light emitted by the associated pixel element, light emitted by other pixel elements calibrated by other light detectors, other pixel elements displaying content Can be distinguished from light emitted by and / or ambient light. By operating the photodetector and its associated pixel element at a specified frequency, the photodetector can filter noise from the surrounding environment of other pixel elements as well as the composite display device.

  With the calibration data, for example, the luminance value measured by the photodetector during calibration can be communicated to the appropriate components that process the data in any suitable manner. For example, calibration data can be transferred to a master controller associated with the paddle. In some embodiments, the calibration data is communicated wirelessly. For example, with reference to FIG. 10, calibration data can be communicated wirelessly from paddle 1002 to paddle base 1020, which is associated with the paddle (used to control the paddle). (E.g., an integrated circuit or chip). In another embodiment, calibration data can be communicated through optical fiber 1006 up to paddle 1020. In some embodiments, calibration data need not be communicated to paddle base 1020 if sufficient local logic is included on paddle 1002 to reset the current setting based on the calibration data. Sometimes.

  The light emitted by the pixel element can be captured in various ways by the associated photodetector. In some embodiments, a cover plate is attached in front of the composite display device, for example, to protect the mechanical structure of the composite display device and / or to prevent or reduce external interference. The cover plate can be made of any suitable material (eg plastic) that is almost transparent. A portion of the light incident on the cover plate is reflected. For example, the cover plate material can reflect 4% of the incident light. In such a case, the luminance intensity of the pixel element is related by a portion of the light emitted by the pixel element that is reflected from the cover plate towards the surface of the composite display and captured by the photodetector. It can be measured by a photodetector.

  In some environments, such as outdoor environments rich in sunlight, the cover plate can cause an undesirable amount of reflection. In such an environment, a wire mesh similar to a window screen may be used to protect the front surface of the composite display device. The wire mesh can be made of any suitable material such as stainless steel and can be appropriately colored. For example, the outside of the wire mesh can be colored black and the inside can be a mirror-like metallic finish that reflects most of the incident light. The mesh opening (ie, the amount of visible area) can be selected appropriately. For example, the mesh can be 96% holes and 4% wires. When the wire mesh is used to protect the front surface of the composite display device, the brightness of the pixel element is reflected from the inner surface of the wire mesh toward the surface of the composite display device and captured by the photodetector. The portion of the light emitted by can be measured by the associated photodetector. In some embodiments, the position of the pixel element relative to the wire mesh may affect the amount of pixel element reflected and captured by the associated photodetector, so that initial calibration during manufacture and subsequent Field calibration is performed with the paddles that make up the composite display at the same fixed location.

  Any suitable light technique can be used to ensure that at least a portion of the light of the pixel element is anyway captured by the associated photodetector. In some embodiments, it may not be necessary to rely at least completely on the reflection of light from the front of the composite display. For example, in some embodiments, a custom lens set that directs or scatters a small portion (e.g., 4-5%) of the light emitted by the pixel element toward the side or associated photodetectors. A custom lens can be placed on the photodetector to better place and / or to better capture light from various angles or directions. In the paddle configuration shown in FIGS. 11A, 11B, 15 and 16, the photodetector is mounted on the front surface of the paddle. In some embodiments, a photodetector is mounted on the back of the paddle and a through hole is formed so that the photodetector can receive or capture light from the associated pixel element mounted on the front of the paddle can do. In such cases, a custom lens that focuses only a fraction of the light emitted from the pixel element through the associated through-hole, for example, so that the associated photodetector on the back of the paddle can capture the light. A set may be attached to a pixel element.

  In various embodiments, different types of photodetectors can be used. As described above, in some embodiments, the color composite display device uses a red sensitive, green sensitive, blue sensitive, and / or white sensitive photodetector. In some embodiments, a photodetector with multiple passbands may be used, for example, to reduce the number of components and thus reduce the cost of the components. For example, in some embodiments, a single photodetector sensitive to red, green and blue can be used instead of separate red, green and blue sensitive photodetectors. FIG. 18A shows one embodiment of the three-band pass characteristic of such a photodetector. In some embodiments, sufficient sensitivity for each passband of the three colors is sensitive to red, green, and blue, i.e., in the single photodetector shown in FIG. There may be no separation. In some such cases, a photodetector that is sensitive to red and blue and a photodetector that is sensitive only to green may be used. FIG. 18B shows the passband (solid line) of the photodetector sensitive to red and blue and the passband (dotted line) of the photodetector sensitive to green.

  As described herein, various techniques can be used to detect and correct luminance shifts and / or color coordinate shifts when pixel elements degrade. Although some examples are presented herein, any suitable technique or combination of techniques can be used.

  Although the above embodiments have been described in some detail for ease of understanding, the invention is not limited to the details presented. There are many alternative ways of implementing the invention. The disclosed embodiments are illustrative and not restrictive.

100 composite display
102,202,222,302,312,426,428,602,612 paddle
1002,1010,1100,1500,1600,1602 paddle
104,304,314,420,604,614,414,434,440,1102,1502 Rotating shaft
108,308,316 areas, areas swept
110 Rectangular display area
204,206,208,210,212,214,216 LED
300,600 Composite display with two paddles
310,424,444 Rectangular display area
318 Overlap
402,404 fig
Composite display device using 410,430 mask
412,418 mask
416,422,436 area, sweep area
429 Blocking area
432,438 paddles, disc
442 areas, areas to be swept, sweep areas
502 paddle panel
504 LED control module
506 Angle detector
508 pixel map
608,616 area, display area
610 images
702,704,706 placement
710,712,714,716,720,722,724,726 Sweep area
1004 shaft
1006 optical fiber
1008 base
1012 optical camera
1014 Marking
1020 paddle base
1104 Photodetector
1106,1300 pixel element
1504 Top row
1506 Photodetector set
1508 LED row
1604 ring
1700 treatment

Claims (20)

A composite display device,
A paddle configured to sweep an area;
A plurality of pixel elements mounted on the paddle;
One or more photosensors mounted on the paddle and configured to measure luminance values of the plurality of pixel elements;
A composite display device in which at least a portion of an image is displayed by selectively driving one or more of the plurality of pixel elements while the paddle sweeps the region.   The composite display device of claim 1, wherein the one or more photosensors are used to identify a degradation of the pixel element.   The one or more light sensors are one or more of a red sensitive light detector, a blue sensitive light detector, a green sensitive light detector, a broadband light detector, a red, green and blue sensitive detector. The composite display device of claim 1, further comprising: a photodetector sensitive to red and blue.   The composite display device according to claim 1, wherein the plurality of pixel elements include one or more of a red light emitting diode, a blue light emitting diode, a green light emitting diode, and a white light emitting diode.   The composite display device according to claim 1, wherein each of the one or more photosensors is associated with one or more pixel elements of the plurality of pixel elements.   The composite display device of claim 1, wherein the pixel element and the associated photosensor are configured to operate at a specified frequency.   The composite display device according to claim 1, wherein a part of the light emitted by the pixel element is reflected from a structure covering a front surface of the composite display device and received by a photosensor associated with the pixel element.   The composite display device according to claim 7, wherein the structure includes a cover plate or a wire mesh.   A plurality of pixel elements are mounted on the front surface of the paddle, at least a subset of the one or more photosensors are mounted on the back surface of the paddle, and the paddle includes one or more through holes, through which the The composite display device of claim 1, wherein a portion of the light emitted by the pixel elements on the front surface of the paddle is transferred to a corresponding light sensor on the back surface of the paddle.   The composite display device of claim 1, wherein a custom lenslet is attached to the pixel element to focus or direct a portion of the light emitted by the pixel element toward an associated photosensor.   The composite display device according to claim 1, wherein luminance values of the plurality of pixel elements are measured by one or more photosensors when the plurality of pixel elements are calibrated.   The one or more optical sensors include a broadband photodetector, and the broadband photodetector includes a luminance value of one or more pixel elements of the plurality of pixel elements and the plurality of pixel elements. The composite display of claim 1, wherein the composite display is used to measure one or both of brightness values of white light generated by driving one or more red, green, or blue pixel elements. apparatus.   The one or more photosensors include a photodetector that is sensitive to one or more colors, and using the photodetector, included in the plurality of pixel elements of one or more colors. The composite display device according to claim 1, wherein a luminance value of one or a plurality of pixel elements is measured.   The composite display device according to claim 1, wherein the plurality of pixel elements are periodically calibrated.   The subset of one or more pixel elements of the plurality of pixel elements is calibrated while the remainder of the pixel elements not included in the subset are displaying at least a portion of the image. The composite display device described in 1.   Calibration data is wirelessly transferred from the paddle to a paddle base on which the paddle is mounted, the paddle base including one or more components used to control the paddle. 2. The composite display device according to 1. A method of constructing a composite display device,
Composing a paddle that sweeps an area;
Mounting a plurality of pixel elements on the paddle;
Mounting one or more photosensors on the paddle,
The one or more photosensors are configured to measure a luminance value of the plurality of pixel elements, and one or more of the plurality of pixel elements while the paddle sweeps the region. A method wherein at least a portion of the image is displayed by selectively driving the pixel elements.   The method of claim 17, wherein the pixel element and the associated photosensor are configured to operate at a specified frequency.   The method of claim 17, wherein a portion of the light emitted by a pixel element is reflected from a structure covering a front surface of the composite display device and received by a photosensor associated with the pixel element.   The method of claim 19, wherein the structure comprises a cover plate or a wire mesh.