EXTENDED DEPTH OF FOCUS INTEGRAL DISPLAYS

Extended depth of focus integral displays are disclosed. An example integral display includes a display screen to display an image including a plurality of interlaced elemental images that represent different views of a three-dimensional (3D) image, and an array of lenses proximate the display to integrate the elemental images to form the 3D image, the lenses selectively switchable between a first focal length and a second focal length to increase a depth of focus of the 3D image. Another example integral display includes a display screen to display an image including a plurality of interlaced elemental images that represent different views of a 3D image, and an array of lenses proximate the display to integrate the elemental images to form the 3D image, the array of lenses including first lenses having a first focal length interlaced with second lenses having a second focal length.

FIELD OF THE DISCLOSURE

This disclosure relates generally to integral displays, and, more particularly, to extended depth of focus (DOF) integral displays.

BACKGROUND

Integral displays are forms of 3D displays that provide multiple views that trigger the perception of a 3D image by providing multiple depth cues for human eyes such as, but not limited to, convergence and/or accommodation cues. Integral displays provide both horizontal and vertical parallax cues, thus differentiating them from autostereoscopic or multi-view displays. Integral displays allow multiple users to simultaneously view the same 3D scene from their own view points. It is not necessary to wear an accessory, for example, special glasses to view the 3D images displayed by an integral display. Tracking of the head or the eyes is also not required to view these displays.

In general, the same reference numbers will be used throughout the drawing(s) and accompanying written description to refer to the same or like parts. The figures are not to scale. Instead, for clarity, some dimensions are enlarged in the drawings. Connecting lines or connectors shown in the various figures presented are intended to represent example functional relationships and/or physical or logical couplings between the various elements.

DETAILED DESCRIPTION

Despite the many advantages of integral displays, conventional integral displays have limited image resolutions, limited DOFs, and limited viewing zones that require tradeoffs in integral display design. For example, to increase DOF, image resolution decreases, and vice versa. With currently feasible display resolutions and pixel densities, only low DOF and low image resolution conventional integral displays are feasible, which do not provide the accommodation cue for full 3D perception. In the case of integral displays, DOF is equivalent to depth of field.

Extended-DOF integral displays are disclosed herein that overcome at least these inherent limitations of conventional integral displays. In examples disclosed herein the DOF can be increased (e.g., extended) by at least a factor of two without decreasing image resolution. In some examples, images are spatially multiplexed using a lenslet array having different focal length lenses. Additionally, and/or alternatively, images are temporally multiplexed using a lenslet array having switchable focal length lenses.

Reference will now be made in detail to non-limiting examples, some of which are illustrated in the accompanying drawings.

FIG. 1illustrates an example extended-DOF integral display100in accordance with teachings of this disclosure.FIG. 2is a top view of the example extended-DOF integral display100ofFIG. 1. The example extended-DOF integral display100ofFIGS. 1 and 2includes an example display screen102and an example lenslet array104in the front of the display screen102. The lenslet array104includes an array of example lenses, one of which is designated at reference numeral106. The example lenslet array104can be implemented to have different focal lengths at the same time, or different focal lengths at different times. The example lenslet arrays300and600discussed below in connection withFIGS. 3A-Cand4-7may be used to implement the example lenslet array104of the example extended-DOF integral display100. In the example ofFIGS. 3A-C,4, and-5, the lenslet array500has lenses of different focal lengths. In the example ofFIGS. 6 and 7, the lenses of the lenslet array600are switchable between two or more focal lengths. Using the example lenslet array300and/or the example lenslet array600, the DOF of the example extended-DOF integral display100can be increased, without decreasing the spatial resolution of generated 3D images.

An example image108displayed on the example display screen102includes a plurality of example interlaced elemental images (one of which is designated at reference numeral202), which represent different views of an example 3D image110. The example display screen102may be, for example, a light emitting diode (LED) display, an organic light emitting diode (OLED) display, a liquid crystal display (LCD) display, a cathode ray tube (CRT) display, an in-place switching (IPS) display, a touchscreen, etc.

To display the image108on the display screen102, the example integral display100ofFIG. 1includes an example display driver112, and an example processor114. The example display driver112ofFIG. 1provides an interface between the example processor114and the display screen102. The example display driver112accepts commands and/or data from the processor114, and generates signals suitable to make the display screen102show desired text, image(s), etc. In the illustrated examples ofFIG. 7, the processor114also controls the switching of the focal lengths of the lenses of a lenslet array.

The example processor114ofFIG. 1obtains, generates, etc. desired text, image(s), etc. to be shown on the display screen102. For example, the desired text, image(s), etc. may be generated using hardware, software, firmware, etc. Additionally, and/or, alternatively, the desired text, image(s), etc. can be obtained from a non-transitory computer-readable storage medium and/or disk. The example processor114is hardware. For example, the processor114can be implemented by one or more integrated circuits, logic circuits, microprocessors, graphic processing units (GPUs), digital signal processors (DSPs), or controllers from any desired family or manufacturer. The hardware processor114may be a semiconductor based (e.g., silicon based) device.

In operation, the example display screen102outputs (e.g., presents, displays, etc.) the image108composed of the interlaced elemental images202. The lenslet array104integrates those elemental images202into the single 3D image110to provide different views and/or parallaxes within an eyebox204(FIG. 2) (e.g., within a viewing zone, view angle206, etc.) where a person116can view the 3D image110. This allows the integral display100to recreate a sampled light field that can be perceived as a 3D image by the person116, with objects perceived to be in front and/or behind the integral display100. Depending on the density of the views generated by the integral display100, the person116can experience parallax and/or retinal blur, making a more robust 3D display, similar to viewing 3D in real world. The example extended-DOF integral display100differs from stereoscopic displays, as the integral display100does not require glasses and works for multiple viewers simultaneously.

The characteristics of the integral display100are defined, at least in part, by parameters of the display screen102and the lenslet array104. In conventional integral displays, the distance g208between the lenslet array104and the display screen102is selected to be the focal length f of the lenses106of the lenslet array104. In this case, the DOF216is the product of the number of pixels in each elemental image202(roughly area under each lens106), and the focal length f of the lenses106. When the distance g208is not equal to the focal length f, the spatial resolution RIof the 3D image, the DOF216of the integral display100, and a location l of the central depth plane (e.g., the plane to which the 3D image110is projected and centered) from the lenslet array104can be expressed mathematically, in the geometrical optics regime, as:

where RIis the effective spatial resolution of the 3D image110, PLis the pitch210of the lenslet array104(e.g., diameter of the lenses106), and Pxis the pixel pitch212of the display screen102.

The example eyebox204ofFIG. 2defines a lateral range214(e.g., width w214of the eyebox204) parallel to the display screen102, in which the person116can move while observing clear 3D images. If the person116moves outside the eyebox204, views of the 3D image110repeat and there is aliasing at the border of the eyebox204. Thus, for comfortable viewing, both eyes of the person116should be located within the eyebox204. The width w214of the eyebox204at a viewing distance d218is given by the following mathematical expressions:

In conventional integral displays there is an inherent tradeoff between spatial resolution RLof the 3D image110, DOF216, and the viewing angle a206. Improvements to one characteristic, reduces the other(s), which can be mathematically expressed as:

where S is the resolution of the display screen102. This implies that, in conventional integral displays, an increase in the DOF216can only be achieved when spatial resolution RLdecreases. An example conventional integral display with a screen resolution of 0.0315 mm and a lens pitch of 0.3145 mm results in a 3D image resolution of 77 pixels per inch (ppi), but only a DOF216of 42 millimeters (mm). For another example conventional integral display, a 0.4448 mm lens pitch results in an image resolution of 57 ppi and a DOF216of 68 mm.

While an example manner of implementing the example extended-DOF integral display100is illustrated inFIGS. 1 and 2, one or more of the elements, processes and/or devices illustrated inFIGS. 1 and 2may be combined, divided, re-arranged, omitted, eliminated and/or implemented in any other way. Further, the example display screen102, the example lenslet array104, the example display driver112, the example processor114and/or, more generally, the example extended-DOF integral display100ofFIGS. 1 and 2may be implemented by hardware, software, firmware and/or any combination of hardware, software and/or firmware. Thus, for example, any of the example display screen102, the example lenslet array104, the example display driver112, the example processor114and/or, more generally, the example extended-DOF integral display100could be implemented by one or more analog or digital circuit(s), logic circuits, programmable processor(s), programmable controller(s), GPU(s), DSP(s), application specific integrated circuit(s) (ASIC(s)), programmable logic device(s) (PLD(s)) and/or field programmable logic device(s) (FPLD(s)). When reading any of the apparatus or system claims of this patent to cover a purely software and/or firmware implementation, at least one of the example display screen102, the example lenslet array104, the example display driver112, the example processor114, and the example extended-DOF integral display100is/are hereby expressly defined to include a non-transitory computer-readable storage device or storage disk such as a memory, a digital versatile disk (DVD), a compact disc (CD), a Blu-ray disk, etc. including the software and/or firmware. Further still, the example extended-DOF integral display100may include one or more elements, processes and/or devices in addition to, or instead of, those illustrated inFIGS. 1 and 2, and/or may include more than one of any or all of the illustrated elements, processes and devices. As used herein, the phrase “in communication,” including variations thereof, encompasses direct communication and/or indirect communication through one or more intermediary components, and does not require direct physical (e.g., wired) communication and/or constant communication, but rather additionally includes selective communication at periodic intervals, scheduled intervals, aperiodic intervals, and/or one-time events.

It has been advantageously discovered that implementing the example extended-DOF integral display100with a lenslet array with an array of lenses of different focal length lenses can increase the DOF216by, for example, a factor of two, without decreasing the spatial resolution RLof the 3D image110.

FIG. 3Ais a front view of an example lenslet array300that can be used to implement the example extended-depth lenslet array104ofFIGS. 1 and 2. Using the example lenslet array300to implement the example integral display100increases DOF by, for example, a factor of two, without decreasing the spatial resolution RLof the 3D image110.FIG. 4is a perspective view of the example lenslet array300ofFIG. 3A.

The example lenslet array300ofFIGS. 3A and 4includes a rectangularly arranged array of lenses302having two different focal lengths (e.g., 2 millimeters (mm) and 2.42 mm). As shown, a set of lenses304having a focal length of 2 mm are alternated with a set of lenses306having a focal length of 2.42 mm. Other focal lengths, and/or, other numbers of focal lengths (e.g., more than 2) may be used. In the example ofFIG. 4, the example lenses304and306are square rather than circular, with a fill factor of greater than 95%.

FIGS. 3B and 3Care front views of example lenslet arrays320and340that can be used to implement the example extended-depth lenslet array104ofFIGS. 1 and 2. In the examples ofFIGS. 3B and 3C, the lenses304and306are hexagonally arranged and/or packed.

FIG. 5is a side view of an example extended-DOF integral display500formed by implementing the example extended-DOF integral display100with the example lenslet array300ofFIGS. 3A-Cand4. When, as shown inFIG. 5, the display screen102is properly spaced from the example lenslet array300in the integral display500, the set of lenses304creates integral images behind the display screen102with a first DOF502, and the set of lenses306creates integral images in front of the display screen102with a second DOF504, doubling the DOF216of the integral display500. In some examples, the spacing g208is determined using the following.

Parameters of the example extended-DOF integral display500can be determined by, for example, choosing a pixel size PX212for the display screen102, and choosing an initial lens pitch PL210and focal length for the lenses304for a desired eyebox204, viewing distance d218, and desired 3D image resolution. Calculate image plane location l using, for example, EQN (1) and spacing g208using, for example, EQN (3) In some examples, the 3D image resolution for the lenses306is selected to be the same as the 3D image resolution for the lenses304, the DOFs308and310are selected to be adjacent, the spacings g208for the lenses304and306are selected to be the same. Hence, the 3D image pixel size is constant. Because g208, PX212, and the 3D image resolution are the same for the lenses304and306, the image plane location l is same. However, l has a different sign for the lenses304compared to the lenses306. In some examples, lenses304and306have the same lens pitch PL210. The focal length of the lenses306is calculated using EQN (3) with the correct sign for l.

An example extended-DOF integral display500for viewing with the naked eye at viewing distance greater than 0.25 meters (m) has the following parameters:a. A display screen102with 806 pixels per inch (ppi) and a pixel pitch Px212of 0.0315 mm.b. A lenslet array300with alternating lenses of 2 different focal lengths, individual lens pitches of 0.3145 mm. Focal lengths of 2 mm and 2.42 mm. Lenses302,304arranged so effective lens pitch PL210diagonally between lenses of the same focal length is 0.4448 mm (e.g., sqrt(2)*0.3145).c. Resulting 3D image resolution of 77 ppi (image spot size of 0.33 mm) with a DOF216of 96 mm. The DOF216is equally distributed in front and behind the display screen102, as shown inFIG. 5.

While an example manner of implementing the lenslet array104ofFIGS. 1 and 2is illustrated inFIGS. 3A-C,4, and5, one or more of the elements, processes and/or devices illustrated inFIGS. 3A-C,4and5may be combined, divided, re-arranged, omitted, eliminated and/or implemented in any other way. Further still, the example lenslet array104ofFIGS. 1 and 2may include one or more elements, processes and/or devices in addition to, or instead of, those illustrated inFIGS. 3A-C,4and5, and/or may include more than one of any or all of the illustrated elements, processes and devices.

FIG. 6is a side view of another example lenslet array600that can be used to implement the example extended-DOF integral display100ofFIGS. 1 and 2. Using the example lenslet array600to implement the example integral display100increases DOF by, for example, a factor of two, without decreasing the spatial resolution RLof the 3D image110.FIG. 7is a side view of an example extended-DOF integral display700formed by implementing the example extended-DOF integral display100with the example lenslet array600ofFIG. 6.

In the illustrated example ofFIG. 6, lenses602of the example lenslet array600are selectively switchable between different focal lengths (e.g., two different focal lengths). To switch the focal lengths of the lenses602, the example lenslet array600includes an example switchable polarizer604and an example birefringent material606sandwiched between two plano-convex lenslet arrays. An example switchable polarizer604is a liquid crystal material switchable between transmitted horizontal polarization and transmitted vertical polarization.

The example birefringent material606has a refractive index that depends on the polarization and propagation direction of light emitted from the polarization switching material604. In the example ofFIG. 6, the birefringent material606is a layer608within the lenslet array600. For example, the birefringent material606can be sandwiched between two micro-lens-arrays (MLA)610and612of the same focal length. The thickness of the layer608depends on the birefringence (e.g., how much refractive index changes with polarization) of the birefringent material606. Example birefringent material606includes calcite, liquid crystals, etc. Other example selectively switchable lenslet arrays include diffractive waveplates, liquid crystal lenses, etc.

When the example switchable polarizer604is in a first state (e.g., horizontal polarization), the example birefringent material606has a first refractive index, and the lenses602have a first focal length. When the switchable polarizer604is in a second state (e.g., vertical polarization), the birefringent material606has a second refractive index, and the lenses602have a second focal length.

When, as shown inFIG. 7, the display screen102is properly spaced from the example lenslet array600in the extended-DOF integral display700, the lenses602create first integral images behind the display screen102with a first DOF702when the lenses602have the first focal length, and create second integral images in front of the display screen102with a second DOF704when the lenses have the second focal length. Implementing the integral display100with the example lenslet array600, the DOF103of the integral display700can be doubled. In operation, the focal lengths of the lenses602are switched fast enough so the person116unconsciously visually fuses the first and second integral images into a single large DOF image without being aware the integral images are changing.

In some examples, the display screen102is updated at 120 cycles per second (Hz) and synchronized with focal length switching of the lenses602. 3D images are changed at a rate of 60 Hz. In general, faster switching improves image quality by reducing potential flicker. Parameters of the example integral display100implemented using the example lenslet array600, such as focal lengths, spacing, etc., can be calculated using, for example, the example mathematical expressions of EQN (1) to EQN (5).

To control the switching of the example polarizer604, the example integral display700includes an example polarization controller706and an example synchronizer708. The example polarization controller706controls the example polarizer604between, for example, two states (e.g., two polarizations). The example synchronizer710ofFIG. 7synchronizes the display of images108with the switching of the states of the polarizer604. For example, the synchronizer708changes the image108at a first rate (e.g., 60 Hz) and switches the state of the polarizer604at a second rate (e.g., 120 Hz).

An example extended-DOF integral display700including the example lenslet array600for viewing with the naked eye at viewing distance greater than 0.25 meters (m) has the following parameters:a. A display screen102with 806 pixels per inch (ppi) and a pixel pitch Px212of 0.0315 mm.b. Two plano-convex MLAs610,162with focal length of 1.92 mm, lens pitches PL210of 0.502 mm, and thicknesses of 0.4741 mm.c. A calcite birefringent material606with a thickness of 1.4186 mm.d. Resultant image resolution is 72 ppi (image spot size of 0.33 mm) with a DOF216of 84 mm. DOF216is equally distributed in front and behind the display. The spacing g208is not equal to focal length.e. Resultant display has approximately 16 views in the eyebox204of 184 mm at a distance of 500 mm.f. Compared to conventional integral displays, the example extended-DOF integral display100ofFIG. 5increases the DOF216by approximately 1.5× for the same image resolution display.

While an example manner of implementing the lenslet array104and integral displays100ofFIGS. 1 and 2is illustrated inFIGS. 6 and 7, one or more of the elements, processes and/or devices illustrated inFIGS. 6 and 7may be combined, divided, re-arranged, omitted, eliminated and/or implemented in any other way. Further, the example polarization controller706and the example synchronizer708may be implemented by hardware, software, firmware and/or any combination of hardware, software and/or firmware. Thus, for example, any of the example polarization controller706and the example synchronizer708could be implemented by one or more analog or digital circuit(s), logic circuits, programmable processor(s), programmable controller(s), GPU(s), DSP(s), ASIC(s), PLD(s) and/or FPLD(s). When reading any of the apparatus or system claims of this patent to cover a purely software and/or firmware implementation, at least one of the example polarization controller706and the example synchronizer708is/are hereby expressly defined to include a non-transitory computer-readable storage device or storage disk such as a memory, a DVD, a CD, a Blu-ray disk, etc. including the software and/or firmware. Further still, the example lenslet array600and integral display700ofFIGS. 6 and 7may include one or more elements, processes and/or devices in addition to, or instead of, those illustrated inFIGS. 6 and 7, and/or may include more than one of any or all of the illustrated elements, processes and devices.

A flowchart representative of example hardware logic or machine-readable instructions for implementing the extended-DOF integral displays100and700ofFIGS. 1, 2 and 7is shown inFIG. 8. The machine-readable instructions may be a program or portion of a program for execution by a processor such as the processor910shown in the example processor platform900discussed below in connection withFIG. 9. The program may be embodied in software stored on a non-transitory computer-readable storage medium such as a compact disc read-only memory (CD-ROM), a floppy disk, a hard drive, a DVD, a Blu-ray disk, or a memory associated with the processor910, but the entire program and/or parts thereof could alternatively be executed by a device other than the processor910and/or embodied in firmware or dedicated hardware. Further, although the example program is described with reference to the flowchart illustrated inFIG. 8, many other methods of implementing the example extended-DOF integral display700may alternatively be used. For example, the order of execution of the blocks may be changed, and/or some of the blocks described may be changed, eliminated, or combined. Additionally, and/or alternatively, any or all of the blocks may be implemented by one or more hardware circuits (e.g., discrete and/or integrated analog and/or digital circuitry, an FPGA, an ASIC, a comparator, an operational-amplifier (op-amp), a logic circuit, etc.) structured to perform the corresponding operation without executing software or firmware.

As mentioned above, the example processes ofFIG. 8may be implemented using executable instructions (e.g., computer and/or machine-readable instructions) stored on a non-transitory computer and/or machine-readable medium such as a hard disk drive, a flash memory, a read-only memory, a CD-ROM, a DVD, a cache, a random-access memory and/or any other storage device or storage disk in which information is stored for any duration (e.g., for extended time periods, permanently, for brief instances, for temporarily buffering, and/or for caching of the information). As used herein, the term non-transitory computer-readable medium is expressly defined to include any type of computer-readable storage device and/or storage disk and to exclude propagating signals and to exclude transmission media.

“Including” and “comprising” (and all forms and tenses thereof) are used herein to be open ended terms. Thus, whenever a claim employs any form of “include” or “comprise” (e.g., comprises, includes, comprising, including, having, etc.) as a preamble or within a claim recitation of any kind, it is to be understood that additional elements, terms, etc. may be present without falling outside the scope of the corresponding claim or recitation. As used herein, when the phrase “at least” is used as the transition term in, for example, a preamble of a claim, it is open-ended in the same manner as the term “comprising” and “including” are open ended. The term “and/or” when used, for example, in a form such as A, B, and/or C refers to any combination or subset of A, B, C such as (1) A alone, (2) B alone, (3) C alone, (4) A with B, (5) A with C, and (6) B with C.

The program ofFIG. 8begins at block802. The example processor114sets the switchable polarizer604to a first state (e.g., a first polarization) (block802). For all images to be displayed (block804), the processor114controls the example display driver112to display an image on the display screen102(block806). The processor114waits for a period of time having a duration of, for example, 1/120 seconds (block808), changes the switchable polarizer604to a second state (e.g., a second polarization) (block810), and waits another period of time (e.g., 1/120 seconds) (block812). When all images have been displayed (block814), control exits from the example program ofFIG. 8.

FIG. 9is a block diagram of an example processor platform900structured to execute the instructions ofFIG. 8to implement the integral displays100,500and700ofFIGS. 1, 5 and 6. The processor platform900can be, for example, a server, a personal computer, a workstation, a self-learning machine (e.g., a neural network), a mobile device (e.g., a cell phone, a smart phone, a tablet such as an IPAD™), a personal digital assistant (PDA), an Internet appliance, a DVD player, a CD player, a digital video recorder, a Blu-ray player, a gaming console, a personal video recorder, a set top box, a headset or other wearable device, or any other type of computing device.

The processor platform900of the illustrated example includes a processor910. The processor910of the illustrated example is hardware. For example, the processor910can be implemented by one or more integrated circuits, logic circuits, microprocessors, GPUs, DSPs, or controllers from any desired family or manufacturer. The hardware processor may be a semiconductor based (e.g., silicon based) device. In this example, the processor900implements the example polarization controller706and/or, more generally, the example processor114.

The processor910of the illustrated example includes a local memory912(e.g., a cache). The processor910of the illustrated example is in communication with a main memory including a volatile memory914and a non-volatile memory916via a bus918. The volatile memory914may be implemented by Synchronous Dynamic Random-Access Memory (SDRAM), Dynamic Random-Access Memory (DRAM), RAMBUS® Dynamic Random-Access Memory (RDRAM®) and/or any other type of random access memory device. The non-volatile memory916may be implemented by flash memory and/or any other desired type of memory device. Access to the main memory914,916is controlled by a memory controller.

The processor platform900of the illustrated example also includes an interface circuit920. The interface circuit920may be implemented by any type of interface standard, such as an Ethernet interface, a universal serial bus (USB), a Bluetooth® interface, a near field communication (NFC) interface, and/or a PCI express interface.

In the illustrated example, one or more input devices922are connected to the interface circuit920. The input device(s)922permit(s) a user to enter data and/or commands into the processor910. The input device(s) can be implemented by, for example, an audio sensor, a microphone, a camera (still or video), a keyboard, a button, a mouse, a touchscreen, a track-pad, a trackball, isopoint and/or a voice recognition system.

One or more output devices924are also connected to the interface circuit920of the illustrated example. The output devices924can be implemented, for example, by display devices (e.g., a light emitting diode (LED), an organic light emitting diode (OLED), a liquid crystal display (LCD), a cathode ray tube display (CRT), an in-place switching (IPS) display, a touchscreen, etc.), a tactile output device, a printer and/or speaker. In this example, the output device924implements the example display screen102and the switchable polarizer604. The interface circuit920of the illustrated example, thus, typically includes a graphics driver card, a graphics driver chip and/or a graphics driver processor. In this example, the interface circuit920implements the example display driver112.

The processor platform900of the illustrated example also includes one or more mass storage devices928for storing software and/or data. Examples of such mass storage devices928include floppy disk drives, hard drive disks, CD drives, Blu-ray disk drives, redundant array of independent disks (RAID) systems, and DVD drives.

Coded instructions932including the coded instructions ofFIG. 8may be stored in the mass storage device928, in the volatile memory914, in the non-volatile memory916, and/or on a removable non-transitory computer-readable storage medium such as a CD-ROM or a DVD.

Example extended-DOF integral displays are disclosed herein. Further examples and combinations thereof include at least the following.

Example 1 is an integral display including a display screen to display an image including a plurality of interlaced elemental images that represent different views of a three-dimensional (3D) image; and an array of lenses proximate the display to integrate the elemental images to form the 3D image, the lenses selectively switchable between a first focal length and a second focal length to increase a depth of focus of the 3D image.

Example 2 is the integral display of example 1, further including a switchable polarizer, and a birefringent material in a first of the lenses, a focal length of the first of the lenses responsive to a state of the switchable polarizer.

Example 3 is the integral display of example 2, wherein the switchable polarizer is selectively switchable between a first polarization and a second polarization, and the first of the lenses is to have a first focal length when the switchable polarizer has the first polarization, and a second focal length when the switchable polarizer has the second polarization.

Example 4 is the integral display of any of examples 1 to 3, wherein the 3D image has a first depth of focus when the lenses have the first focal length, and the 3D image has a second depth of focus when the lenses have the second focal length.

Example 5 is the integral display of any of examples 1 to 4, wherein the 3D image is presented at a first location when the lenses have the first focal length, and the 3D image is presented at a second location different than the first location when the lenses have the second focal length.

Example 6 is the integral display of example 5, wherein the first location is perceivable as behind the display, and the second location is perceivable as in front of the display.

Example 7 is the integral display of any of examples 1 to 6, wherein the integral display displays the 3D image during a first period of time with a first depth of focus while the lenses have the first focal length, and displays the 3D image during a second period of time with a second depth of focus while the lenses have the second focal length, durations of the first and second periods of time selected so a person can perceive the 3D image with a third depth of focus greater than the first depth of focus and the second depth of focus.

Example 8 is the integral display of any of examples 1 to 7, further including a display device to control the display screen to display the image, and a processor to control switching of the lenses between the first focal length and the second focal length, and provide the image to the display device.

Example 9 is a method including passing an image through an array of lenses, the image including a plurality of interlaced elemental images that represent different views of a three-dimensional (3D) image, integrating, with the array of lenses, the elemental images to form the 3D image, and switching the lenses between a first focal length and a second focal length while the elemental images are integrated to increase a depth of focus of the 3D image.

Example 10 is the method of example 9, wherein the image is a first image, further including passing a second image through the array of lenses, wherein the focal lengths of the lenses are switched between the first image and the second image passing through the array of lenses.

Example 11 is the method of example 10, further including switching the lenses between the first focal length and the second focal length while elemental images of the second image are integrated with the array of lenses to increase a depth of focus of a second 3D image.

Example 12 is the method of any of examples 9 to 11, wherein the lenses are switched between the first focal length and the second focal length by switching a polarizer between a first polarization and a second polarization.

Example 13 is the method of any of examples 9 to 12, wherein the 3D image has a first depth of focus when the lenses have the first focal length, and the 3D image has a second depth of focus when the lenses have the second focal length, the first depth of focus perceivable as behind a display, the second depth of focus perceivable as in front of the display, the 3D image perceivable by a person as having a third depth of focus greater than the first depth of focus and the second depth of focus.

Example 14 is a non-transitory computer-readable storage medium comprising instructions that, when executed, cause a machine to at least pass an image through an array of lenses, the image including a plurality of interlaced elemental images that represent different views of a three-dimensional (3D) image, integrate, with the array of lenses, the elemental images to form the 3D image, and switch the lenses between a first focal length and a second focal length while the elemental images are integrated to increase a depth of focus of the 3D image.

Example 15 is the non-transitory computer-readable storage medium of example 14, including instructions that, when executed, cause the machine to pass a second image through the array of lenses, wherein the lenses are switched between the image and the second image passing through the array of lenses.

Example 16 is the non-transitory computer-readable storage medium of any of examples 14 to 15, including instructions that, when executed, cause the machine to switch the lenses between the first focal length and the second focal length by switching a polarizer between a first polarization and a second polarization.

Example 17 is the non-transitory computer-readable storage medium of any of examples 14 to 16, wherein the 3D image has a first depth of focus when the lenses have the first focal length, and the 3D image has a second depth of focus when the lenses have the second focal length, the first depth of focus perceivable as behind a display, the second depth of focus perceivable as in front of the display, the 3D image perceivable by a person as having a third depth of focus greater than the first depth of focus and the second depth of focus.

Example 18 is an integral display including a display screen to display an image including a plurality of interlaced elemental images that represent different views of a three-dimensional (3D) image, and an array of lenses proximate the display to integrate the elemental images to form the 3D image, the array of lenses including first lenses having a first focal length interlaced with second lenses having a second focal length.

Example 19 is the integral display of example 18, wherein the first lenses and the second lenses are interlaced according to an alternating pattern.

Example 20 is the integral display of any of examples 18 to 19, wherein the first lenses output the 3D image with a first depth of focus, the second lenses output the 3D with a second depth of focus, the 3D image perceivable by a person with a third depth of focus greater than the first depth of focus and the second depth of focus.

Example 21 is the integral display of any of examples 18 to 20, wherein the first lenses and the second lenses are hexagonally arranged.

Example 22 is the integral display of any of examples 18 to 20, wherein the first lenses and the second lenses are rectangularly arranged.

Example 23 is the integral display of any of examples 18 to 22, wherein the array of lenses further includes third lenses having a third focal length interlaced with the first lenses and the second lenses.

Example 24 is a method including passing an image through an array of lenses, the image including a plurality of interlaced elemental images that represent different views of a three-dimensional (3D) image, the array of lenses including first lenses having a first focal length interlaced with second lenses having a second focal length, integrating, with the first lenses, the elemental images to form a first 3D image with a first depth of focus (DOF) and first perceived location, integrating, with the second lenses, the elemental images to form a second 3D image with a second DOF and second perceived location.

Example 25 is the method of any of example 24, wherein a person perceives the first 3D image and the second 3D image as a third 3D images having a third DOF greater than the first DOF and the second DOF.

Example 26 is the method of any of examples 24 to 25, wherein the first perceived location is in front of a display, and the second perceived location is behind the display.

Example 27 is the method of any of examples 24 to 26, wherein the first lenses and the second lenses are interlaced according to an alternating pattern.

Example 28 is the method of example 27, wherein the first lenses and the second lenses are hexagonally arranged.

Example 29 is the method of example 27, wherein the first lenses and the second lenses are rectangularly arranged.