Patent Description:
Traditional lighting sources have long been placed in arrangements to create arrays of lights. A video screen comprised of individual filament bulbs is one example of a lighting array. With independent control of each bulb, the array can be addressed to visualize information. The quality of the array can be improved by adding multiple colors and increasing the resolution. However, traditional lighting sources generally present information as an on-or-off state. Thus, the array is limited to a <NUM>-dimensional display of colors.

Laser lighting is a promising illumination source due to its increased directionality, higher power densities, beam shaping without the use of a global lens element, and ability to be designed with discrete light properties (i.e. wavelength, power, irradiance, coherence, polarization, divergence, and directionality). With control over the discrete properties of laser light, more information can be provided than simply on-or-off. In addition, lasers with low divergence can present three dimensional shapes. However, laser lighting has not been widely adopted for use as direct lighting sources due to the current technological limitations of lasers and the concerns for eye safety. As such, the benefits associated with laser lights are not realized. Therefore, it would be advantageous to develop a laser array that can be used as a replacement for traditional bulbs, illumination sources, and even pixels used in displays.

<CIT> discloses a graphical display station of arbitrary shape such as channel letters or other shaped structures is populated with pixels which are components of flexible pixel strings which can be arranged to fit the arbitrary shape(s).

<CIT> discloses an LED image display system with rigid frames positioned in at least one vertical stack forming a planar vertical display, with vertical rigid bar members mounted to each of the frames and with equal spacing, and LED pixels mounted to each bar member.

<CIT> discloses an apparatus and methods for lighting and displays as well as to a display module for use in the lighting or displays.

<CIT> discloses a device that can efficiently produce a highly resolved intensity profile that can be easily switched to various specific configurations with binary word strings defining output intensities that after summation will be combined to form a single colors intensity depth.

<CIT> discloses how a low-resolution image is displayed at high resolution and power consumption is reduced.

<CIT> discloses a light beam scanning projection apparatus comprising a plurality of light beams, a reflection mirror for reflecting the light beams to project them onto a screen or the like, and a mirror driving unit for driving the reflection mirror so that the plurality of light beams are incident on the reflection mirror with different optical axes and projected on different projection areas.

The present invention uses a laser array as a light source. The laser array can be used much like traditional lighting sources are used and can even be used to replace pixels in video screens.

The present invention provides a laser array and a method of controlling a laser array as claimed.

The benefits of the direct laser light source of the present invention include: (<NUM>) direct beam shaping by array; (<NUM>) incredibly sharp, focusable beam (<NUM>) more directional than other existing light sources; (<NUM>) highest potential irradiance of any light source; and (<NUM>) more efficient than LED light sources due to elimination of lossy reflectors. The lasers in the array can output light directly or through optics.

Described herein is an array <NUM> of lasers that can be used in various settings. <FIG> depicts a simple linear array of lasers elements <NUM>. In this particular example, ten individual laser elements <NUM> are separated by a distance of <NUM>. In the preferred embodiment, the laser element 101comprises red, green, and blue laser diode laser sources <NUM> which are combined into a collinear beam. However, any type of laser known in the art can be used. The operator has independent control of the intensity of each color of the sources <NUM> of each element <NUM> in the array <NUM>, allowing the operator or control system to display any color. The color information can be changed at fast visual rates ranging from <NUM> to <NUM>, for example, allowing the display of content such as video. The array <NUM> is controlled by a standard lighting control protocol, such as DMX, with each laser element <NUM>, comprised of one or multiple sources <NUM>, that is part of the array <NUM> controlled independently.

<FIG> is an alternative embodiment of the laser array <NUM>. In this embodiment, the array <NUM> is comprised of twenty separate laser elements <NUM>, each separated by a distance of <NUM>. The array <NUM> in <FIG> has a much smaller pitch, or spacing between elements <NUM>, than the array in <FIG>. <FIG> shows two arrays <NUM> joined end-to-end. The DMX control and power supplies can be daisy chained between each individual array <NUM>. A communication port, such as ArtNet, is also included. A simple video can be mapped to the laser elements <NUM> with the included communication and control interfaces <NUM>. <FIG> shows yet another embodiment of the laser array <NUM>, with multiple smaller arrays <NUM> joined together. An array <NUM> of this pitch could be used for stage lighting effects, video, commercial displays and research, for example. Again, any color could be specified for each individual laser element <NUM> that makes up the array <NUM>.

<FIG> is a two-dimensional array <NUM> of laser elements <NUM>. The array <NUM> can be a singular unit or it could comprise several linear arrays <NUM> arranged side-by-side. In the particular example shown in <FIG>, twenty linear arrays <NUM> are placed next to each other, forming a low pitch and low resolution video screen. Given the modular nature and interconnectability of individual units, the arrays <NUM> are scalable to any size. <FIG> shows an example of a larger two-dimensional array <NUM> of roughly <NUM> by <NUM> meters. In this example, the resolution is <NUM> x <NUM> pixels, with each laser element <NUM> representing a pixel. Throughout this disclosure, the term "Lixel" is used to describe a pixel created by a laser element <NUM> in the array <NUM>. Lixels may be monochomatic or polychromatic and Lixels can emit light within the visible or invisible electromagnetic spectrum, or a combination of both.

<FIG> shows an alternative view of the array <NUM> depicted in <FIG>. Because lasers are point sources, rather than extended sources, the beam emanating from each Lixel is collimated in the preferred embodiment. So when a person views the laser array <NUM>, the image can be presented as a three-dimension shape appearing at a distance from the array <NUM>. This presentation is in stark contrast to the image created by a traditional video screen, where the image is flat. However, in alternative embodiments, each Lixel has an increased angular subtense to increase viewing safety. With a scaled array <NUM> of this size, a video can be displayed on the device. <FIG> show the laser arrays <NUM> of varying sizes and shapes, according to different embodiments, without the laser light visible above the array <NUM>.

When used as a Lixel array, the array <NUM> may be bitmap controlled on a Lixel by Lixel basis as to color mixing levels and intensity. Accordingly, beam profiles are sculpted and stationary or moving images are projected. In the case of a Lixel array, used in automotive headlights as an example, the Lixels are physically built into an array shape that matches the intended purpose. Each Lixel element is aimed at the intended location in the far field, eliminating the need for any global lenses as used with single point sources. Auto engineers struggle to produce a light that fits in the car, focuses on the road exactly where they want, and in intensities that they want. With the Lixel array, the light becomes a freeform construct. Moreover, certain objects in the field of view may be highlighted dynamically such as road signs, debris, wildlife, or other objects of interest.

In the example of an automotive headlight, it is important to note that the array <NUM> is not bound to planar arrays. Shaping and directionality of the Lixels of the array <NUM> allow an exacting light profile to be created without the use of reflectors. An example of a non-planar embodiment is shown in <FIG>.

The benefits of a Lixel array <NUM> used as a light source are as follows:.

Moreover, by combining different colored sources <NUM> in the array <NUM>, a combined light source can be created. For example, red, green, and blue laser sources <NUM> can be combined to create a white laser light output. As a result, a laser array <NUM> could be used as a replacement for LED, Tungsten, and Florescent light sources that are typically used in home light bulbs, outdoor floodlights, street lights, spot lights, theatrical lights (PAR, Source <NUM>, Spotlights, and moving yoke light, for example). Given the efficiency and power density of laser light sources, a 9000W spotlight could be replaced by a 150W laser source.

Examples of various embodiments where several color laser sources <NUM> are combined to form white light are shown in <FIG>. In <FIG>, three laser sources <NUM> are combined through the use of dichroic mirrors to form a combined beam. The laser sources <NUM> could be red, green, and blue, which would create a white combined beam. Other color lasers could be used depending on the desired output. Moreover, the power of each laser could be addressed such that the resulting combined beam is capable of displaying a range of colors. In this manner, the Lixel operates similar to a traditional pixel, where varying amounts of red, green, and blue light are combined to form a pixel of any color. <FIG> shows closely spaced laser sources <NUM>, where the component wavelengths appear to merge from the perspective of a viewer at a given distance. To enhance the quality of a proximate combining method, a global lens that alters all beams simultaneously, or discrete lenses that alters the component beams individually, may be employed. Such a method is shown in <FIG>. <FIG> shows a group of closely spaced Lixels, each Lixel having a red, green, and blue component. <FIG> shows a Lixel array comprising a semiconductor chip. In this embodiment, the semiconductor chip has several laser sources <NUM><NUM> of red, green, blue, or white on the same chip. <FIG> shows an arrangement, which is not independently claimed as such, in which each color of a Lixel is added sequentially before exiting as a combined beam.

To create one color temperature of white light, red, green, and blue laser sources <NUM> are combined in the ratio of <NUM>% R @ <NUM>, <NUM>% B @ <NUM>, and <NUM>% G @ <NUM>. Other combinations of the three sources <NUM> create a combined output other than white. Sources <NUM> can be combined by dichroic filter methods (<FIG>), prism methods, colinear/proximate methods (<FIG>), or others to create coincident parallel beams. The combined laser beam from the sources <NUM> is up-collimated with optics to create a high diameter, low divergence beam. Though red, green, and blue is used as an example, the invention is not to be limited to these wavelengths. The present invention can use one or more wavelengths of visible or invisible light for output.

Costs will initially limit the size and resolution of Lixel arrays. The spacing of a pixel, or the pitch, of a screen determines the resolution or clarity of the projected image. Television screens and monitors, which are adapted for close viewing, tend to have smaller pitches than video screens viewed in a stadium. However, low pitch screens can often be found in use in the touring entertainment market, where 'gag' effects are commonly found. Low dot pitch laser arrays could be used to emulate fixtures such as the Krypton <NUM> (Element Series) lighting array. This traditional array is a simple grid of 5x5 halogen or krypton bulbs that are controlled independently. The spacing is approximately <NUM>" (<NUM>), and thus the device has a <NUM> inch (<NUM>) pitch. A computer can be used to generate images on this very low resolution display when enough panels are connected edge to edge in horizontal rows, vertical rows, or typically in both directions.

Another analogy is the typical video wall used in touring productions and stage presentations. These video walls are quite advanced, often having a pitch of <NUM> or less, but with pitches commonly in the range of <NUM>-<NUM>. The most desirable and costly screens have an even lower dot pitch. For example, high end displays have higher density screens with a dot pitch of. The screens are erected in modular panels that can attach endlessly in both directions. Each panel is capable of bearing the weight of the adjacent panels, and accordingly, screens up to many hundreds of feet wide are possible limited only by inventory and budget. A Lixel array having both low and high pitch densities that are compatible electrically and mechanically with conventional video wall panels could be used in the entertainment industry.

Referring again to the benefits of laser as light sources, each Lixel of the array <NUM> can be shaped. The emitter pattern can range from a low divergence, coherent laser dot, to a highly divergent and diffuse dot. Moreover, Lixels may be collimated through an optical telescope to control diameter and divergence and Lixels may have their coherence disturbed in order to achieve viewer eye safety at a lower divergence and/or closer distance. Adjustment of Lixel beam dynamics may be controlled by electrical (or other) actuated elements to control and shape the beam in any speed, in real time, with typical speeds matching video refresh speeds: <NUM>, <NUM>, <NUM> and faster.

<FIG> shows examples of how a laser array <NUM> could be used as a video screen. <FIG> shows a sample image mapped into a grid pattern, with each grid representing a pixel. <FIG> shows the same image, with each grid representing an individual laser element <NUM> in the array <NUM>. The X, Y, Brightness, red, green, and blue data are mapped to the Lixels in the same manner as they would be mapped to pixels. Because of the collimated nature of laser light, the image projected by the laser array <NUM> is not bound to the two-dimensional surface of the array <NUM>. Rather, the image extends continuously from the surface and propagates for a distance, depending on the quality and nature of the laser light. In other words, each Lixel element may exit the array as a collimated laser beam if the Lixel is programmed as such. <FIG> is a depiction of the sample image projected from the surface of the array <NUM>. The viewer may be directly inside the projected image. However, the images projected by the laser array can be animated such that three-dimensional shapes move around and over the viewers. For example, a sheet or plane of horizontal light can travel from the bottom of a laser array <NUM> to the top of the array by sequencing the illumination of horizontal groups of Lixels.

As another example of the effects that can be created by a laser array <NUM>, <FIG> shows the image when other dimensions are manipulated. For example, setting the depth (or Z-depth) of the image by commanding the position of the waist beam allows the control of light solids in three-dimensional space. Not only is this effect visually appealing for entertainment, advertising, and consumer displays, but this feature could also be used for visualizing complex data sets.

Another benefit of a laser array <NUM> in the entertainment touring industry, or in other uses, is the elimination of flicker. In typical laser projection systems, a single laser is used with a scanner to deflect the beam. By moving the beam and controlling the color at given points in time, a method of time division allows the creation of shapes. This method is limited because the image appears from a single source and diverges in a cone-shaped geometry as the distance from the source increases. In addition, the maximum size of a projected shape is limited to the tangent of the maximum scan angle multiplied by the distance to the screen or observer. With a laser array <NUM>, each position having an X, Y, and Z coordinate is represented by one Lixel, meaning time division is not required to share the laser beam at any point in space. The result is no flicker and the elimination of a maximum size of projected image.

Other benefits of a laser array <NUM> will be discussed. For example, LED or other light source elements can be intermixed with the Lixels of an array to facilitate the simultaneous projection of flat video and dynamic Lixel content that extends beyond the screen, create extruded midair sculptures, and directly engage the audience.

Lixels may be steerable. A typical Lixel propagates a beam perpendicular to its mounting surface, but external electrical or mechanical elements may steer the direction of the Lixel beam.

Lixels may have individually controllable polarization per element, allowing for a 4th dimension (extruded 3D physically, additional implied dimension via common polarized viewing elements such as active or passive polarized glasses.

Attributes of the projection data may be paired with Lixel beam quality. For example, color data might be interpreted by an external processor in order to dynamically change beam focus, polarization, or intensity.

External data sources may make use of Lixel beam properties to visualize data sets requiring more than two dimensional data. Since a laser is highly controllable and shapeable, the laser array can take advantage of these attributes for the visualization of data. For example, each vector stored in a Lixel includes:.

Focus or Z-Depth: By attaching an electrically focusable lens to each Lixel, the location of the waist beam can be controlled in space. That is, the beam will reduce from a fat area to a thin area and then back to fat again. The beam will be highly concentrated at this waist or focus position. By manipulating the Z-Depth at the same speed as the other elements, a three dimensional "Light Solid" is created.

Each vector stored in a Lixel can further include:
Color component values Red, Green, and Blue (R G B) in a scale from <NUM>-<NUM>%. These primary colors represent basic color mixing.

Brightness is included by reference with RGB level control. Any brightness of any color may be achieved.

X&Y coordinates are created by determining which elements, or Lixels, are activated.

Polarization: A Lixel may be comprised of sources with both horizonal and vertical polarized laser sources. In an alternative embodiment, the array uses a polarization modifying optical element such as a common 'polarization rotator' which is electrically controlled for each Lixel. By altering the polarization as a function of time, an additional dimension is created. A viewer with polarization sensitive eyewear can have separate images, or altered images, presented to each eye. This can project selective data by filtering it from the display, or it can create three-dimensional content.

Time: Each Lixel is independently controllable for the period of time in which it is emitting a beam. This time could indicate a data parameter in the visualization, or it may be timed to match the refresh rate of LCD shuttered eyewear as is common in active 3D television glasses. An embodiment of the technology allows an extra depth of 3D, or a method of selectively refreshing actual Light Solids 3D content to each eye.

Beam Diameter: Using the same hardware as the Z-Depth, by extending the travel of the focal device, the beam size may be manipulated in real time to each Lixel element.

Scan Speed: One embodiment of the Lixel uses a scanning element to achieve safety. A laser beam <NUM>/<NUM> the diameter of the aperture orbits the central axis of the aperture. The speed is variable, and may be used to create persistence of vision that appears as a solid to the viewer. However, the movement of the beam creates a minimum angular velocity and dwell time that permits direct occular viewing.

Lixel Orientation: A Lixel may have up to three degrees of rotation, and three degrees of freedom. Accordingly, up to <NUM> additional data points may be stored for each Lixel. An example would include Lixels with a simple X/Y rotation that enables the direction of emission for the Lixel to change dynamically with the input signal.

So at any point, any one Lixel has the independent ability to have the following variables, or display vectors, simultaneously controlled: Red Intensity, Green Intensity, Blue Intensity, and additional primary color Intensities, Brightness, Focus or Z-Depth, Polarization, Time, Beam Diameter, Scan Speed, and Lixel Orientation, without limitation. The streaming or static input content will dictate which Lixel elements receive the content, which are the X&Y positions active in the Lixel Array.

The projection of complex data might be compared to a signal feeding a television display. Red, Green, and Blue are sending separate intensity values for the entire screen array at any given time. In the advanced Lixel displays, additional 'layers' or data are also being sent.

Such additional lasers allow a Lixel screen to use the 3D volume in front of the screen to simultaneously communicate many complex variables. This will allow the visualization of many complex data sets such are found in scientific and medical disciplines. Additionally, it will create opportunities for entertainment and visual displays using this additional 'deep variables' Home appliances, interaction with devices and the environment, and advertising will all benefit from these complex 'real-world, real-3D' display devices.

The Lixel embodiment can be an individual element with these properties and a collection of Lixels in orderly and/or organic arrangements. Such arrays may be linear (strip), two dimensional (flat X/Y array), or three dimensional. (X/Y/Z array).

Multiple Lixel types 'personalities' may be combined within one collection of Lixels as necessary to visualize the appropriate data.

The laser arrays <NUM> can be useful in replacing traditional lighting sources. A typical theatrical Fresnel light housing is illustrated in <FIG>. These fixtures make use of conventional light sources such as tungsten, arc lamps of several varieties, HID discharge, and even LED. In the arrangement shown in <FIG>, which is not independently claimed as such, these conventional light sources are replaced with a laser light source.

Red, green, and blue laser sources are combined to form a white combined beam. The white beam passes through an optical telescope assembly, compound if necessary, to achieve desired beam size and profile, to produce an initial beam diameter which is compatible with the fixture body diameter. It is also possible to use Lixel arrays that have a much larger initial beam diameter than directly combined laser beams or even an array that is equal in size to the fixture body diameter, or even the final projected diameter. Beams that are smaller than the far field projection diameter may pass through an optical telescope. Adjustment of the optical telescope permits adjustment of the far-field beam size. Mechanical stops may be incorporated to prohibit the user from creating a converging focus output which would introduce unwanted high power densities.

Some amount of beam degradation may be introduced to allow for eye safety including, but not limited to: increased divergence, reduced power, polarization, reduction of coherence, reduction of directionality, or introduction of diffusive or other disruptive optical elements. The amount of optical degradation may be adjustable. For example, purposefully introducing 'contaminants' (or enhancements) into one or more layers of the solid state semiconductor laser could be used to degrade the beam quality, removing the laser source from the purview of FDA regulation. In other words, the laser beam could be disturbed sufficiently for the laser source to qualify as a traditional light source, rather than a laser source.

It must be noted that the fixture requires no focus. The light source has infinite focus due to the laser sources. However, in the case of the Fresnel embodiment, it would be desirable to emulate current zoom angles as are currently available. For example, many fixed zoom lens attachments are available such as <NUM> degrees or <NUM> degrees. Some have a user selectable zoom which may be manually adjusted within a range such as <NUM>-<NUM> degrees. A fixed zoom fixture would be optimized for the brightest safe output within the projected far-field area. This would essentially be the maximum brightness, or irradiance, allowed by law.

In replacing traditional light sources, the laser array <NUM> can be located in traditional fixtures. For example, the laser array shown in <FIG> can be placed in a moving yoke. In this example, multiple parameters may be controlled by DMX, ArtNet, or other industry standard control. Basic functions without limit are: pan, tilt, iris, zoom, shutter, framing, color mixing, color correction (CTO), gobo select, gobo index, gobo rotate, prism, frost, effects wheels, focus, polarization, directionality, and bitmapped control of lixel elements. A safety system may be incorporated to allow fixture velocity and the movement of physical functions listed previously without limit to increase fixture brightness dynamically. Movement of a fixture or components of the fixture reduces the viewer's eye exposure time and allows for improved brightness and beam characteristics.

Using the bitmapped function of the laser array <NUM>, by projecting shapes at less than <NUM> percent of the array elements, also allows the safety system to increase brightness. The safety system may also use yoke position information to create a user defined map with no viewer access, and to increase brightness and beam characteristics in those areas. The safety system may also make use of sensors or environmental markers to define areas of high and low power output that correspond to unoccupied or occupied viewer areas. The safety system may be aware of user control inputs that create hazardous beams, and prevents such conditions. The system may incorporate mechanical limits to intrinsically prevent unsafe output, such as stops on the safe zoom extents.

A light source utilizing a laser array <NUM>, such as shown in <FIG>, will benefit from a lighter design, since the arc lamp power supply is eliminated. For the moving yoke example, the fixture responds to controls more accurately since there is less mass to move. In addition, the reduction of suspended weight in overhead lighting reduces materials and engineering costs. Other benefits include more rugged design with no bulbs to break. Increased consistency since laser diodes maintain output and color temperature over full lifetime. Traditional bulbs shift color temperature as they age and require replacement prior to failure for aesthetic purposes.

An additional example of replacing a traditional light source with a laser array <NUM> is shown in <FIG>. In this example, the laser array <NUM> is rotating to control maximum exposure values using a variable time constant instead of continuous exposure constants. This embodiment allows a much brighter output while maintaining safety.

Claim 1:
A laser array (<NUM>), comprising:
a first laser element (<NUM>) comprising a plurality of laser sources (<NUM>), wherein the plurality of laser sources (<NUM>) are combined to form a first collimated laser element output beam;
at least one additional laser element comprising a plurality of additional laser sources (<NUM>), wherein the plurality of additional laser sources (<NUM>) are combined to form at least one additional collimated laser element output beam;
wherein each laser element forming the laser array (<NUM>) comprises at least one adjustable beam parameter to manipulate the respective collimated laser element output beam;
a control interface (<NUM>) configured to independently adjust each of the at least one adjustable beam parameters,
characterized in that
the at least one adjustable beam parameter comprises a beam focus position, and
each laser element forming the laser array (<NUM>) further comprises an electrically focusable lens configured to control the location of a waist in the respective collimated laser element output beam.