TWI499803B - Directional waveguide-based backlight,method for generating a multiview 3d image and waveguides - Google Patents

Description

Backlight based directional waveguide, method for generating multi-view 3D image and waveguide

The present invention relates to a directional waveguide based backlighting technique with integrated lasers for use in a multi-view display screen. This application is related to PCT Patent Application No. PCT/US2012/035573 (Attorney Docket No. 82963238), filed on Apr. 27, 2012, entitled <RTIgt; A PCT patent application filed at the same time as the present application entitled "Backlight Technology for Directional Waveguides for Multi-View Display Screens" and assigned to the assignee of the present application; .

The ability to display the reproduced light field in the screen has become a major exploration target in imaging and display technology. A light field is a collection of all rays of light that travel through each point in each direction in space. Any natural real world view can be fully scribed by its light field, and its light field provides information about the intensity, color and direction of all light passing through the scene. The purpose is to enable a viewer of a display screen to experience the scenery as one can experience.

Today in TV, personal computers, laptops and mobile devices Most of the available display screens still maintain a two-dimensional pattern, and therefore cannot accurately reproduce a light field. Three-dimensional (3D) displays have recently been born, but suffer from insufficient angular and spatial resolution and can only provide a limited number of images. Examples include 3D displays based on stereoscopic images, parallax barriers or lenticular lenses.

A common topic in these displays is the difficulty of fabricating light field displays that are controlled with pixel level accuracy to achieve good image quality over a wide range of viewing angles and spatial resolutions.

According to an embodiment of the present invention, a directional-based waveguide-based backlight having an integrated hybrid laser for use in a multi-view display screen is specifically provided, comprising: a waveguide layer having a plurality of waveguide arrays, each waveguide The array has a plurality of waveguides, each waveguide having a plurality of directional pixels to scatter a plurality of input plane beams into a plurality of directional beams, each directional beam having a directionality from the plurality of directional pixels The direction and angular spread controlled by the nature of the pixel; and a plurality of hybrid lasers disposed in a substrate coupled to the waveguide layer to provide a plurality of input planar beams.

100, 200, 215, 500, 700, 900, 940, 1100 ‧ ‧ directional backlight

105a-d, 205a-d, 220a-d, 305, 325, 400, 705a-d, 905a-d, 945a-d, 1120‧‧ mixed laser

110, 210, 225, 310, 510, 610, 710, 1115‧‧‧ base

115a-d, 120a-d, 515a-d, 520a-d, 910a-d, 915a-d, 950a-d, 955a-d‧‧‧ planar beam

125a-d, 315, 340, 420, 525a-d, 615, 715a-d, 805a-c, 920a-d, 960a-d, 1000‧‧ ‧Band

130a-d, 530a-d, 620a-b, 645a-b, 720a, 810a-c, 925, 965, 1020a-e‧‧‧ directional pixels

135a-d, 535a-d, 820a-c, 930, 970‧‧ ‧ directional beam

140a‧‧‧groove/grating

230‧‧‧ axis

300, 600‧‧‧ top view

320, 625‧‧‧ side view

330, 635‧‧‧矽 oxide layer

335, 640‧‧ ‧ layers

405‧‧‧III-IV area/III-IV group quantum well area/III-V group active area/III-IV group layer/III-V material

410‧‧‧矽/矽Oxide layer

415‧‧‧ nitride layer

505a-d, 605, 630‧‧‧ distributed feedback laser/DFB laser

800‧‧‧ Backlight

815a-c‧‧‧beam

935, 975‧‧3D images

1005a-e‧‧‧Wave area

1010‧‧‧ Angle section

1015a-b‧‧‧ horizontal section

1105a-c‧‧‧Wave array

1110‧‧‧ observation section

1200~1215‧‧‧Steps

L ‧‧‧raster length

W ‧‧‧raster width

Θ‧‧‧ azimuth angle

Λ‧‧·Grating pitch

△Θ‧‧‧ Angle spread

The present application will be more fully understood from the following detailed description in conjunction with the accompanying drawings in which FIG. 2A-B is a schematic diagram of a top view of a waveguide-based directional backlight having an integrated hybrid laser; 3 is a different top and side cross-sectional view of a directional backlight; FIG. 4 is a schematic diagram of an example hybrid laser; and FIG. 5 illustrates a directional backlight using a distributed feedback laser according to various examples. FIG. 6 is a different top and side cross-sectional view of the directional backlight of FIG. 5; FIG. 7 is a 3D view of a directional backlight according to various examples; FIG. 8 illustrates another 3D of an example directional backlight. 9A-B are top views of a directional backlight according to various examples; FIG. 10 illustrates an example of a waveguide having geometrically distinct regions; and FIG. 11 illustrates a direction of a plurality of waveguide arrays including the waveguide of FIG. A schematic diagram of a backlight; and FIG. 12 is a flow chart for generating a 3D image with a directional backlight according to various examples.

A backlight based directional waveguide with an integrated laser for a multi-view display screen is disclosed herein. This directional backlight produces a plurality of input planar beams for a waveguide layer composed of a plurality of waveguide arrays using an integrated hybrid laser. The hybrid lasers can include a hybrid enamel ring laser and a distributed feedback type laser disposed in a ruthenium/iridium oxide substrate coupled to the waveguide layer. Each waveguide array consists of a set of waveguides. Each waveguide consists of multiple directional pixels The composition is configured to direct the input planar beam and the scattered partial beam into an output directional beam. The input planar beam propagates in substantially the same plane as the directional backlight designed to be substantially planar.

In various examples, the directional pixels have patterned gratings disposed in substantially parallel and inclined grooves in the waveguide or at the top. The waveguide can be, for example, a dielectric or polymer waveguide or the like. The patterned grating may comprise a trench etched into the waveguide or a trench formed of a material deposited on top of the waveguide (e.g., any material that may be deposited and etched or removed, including any dielectric or metal).

As described in more detail below, each directional pixel can be a grating length (i.e., a measure of the axis of propagation along the input plane beam), a grating width (i.e., a measure of the propagation axis across the input plane beam). , a groove orientation, a pitch, and a duty cycle. Each directional pixel can emit a directional beam whose direction is determined by the groove orientation and the grating pitch. The angular spread is determined by the length and width of the grating. Using a duty cycle of 50% or so, the second Fourier coefficient of the patterned grating disappears to prevent additional unwanted light scattering. This ensures that only one directional beam is emitted from each directional cell regardless of the output angle.

As described in further detail below, a directional backlight can be designed to contain directional pixels having a certain grating length, grating width, groove orientation, pitch, and duty cycle. Each directional pixel can produce a directional beam having a given field of view such that a plurality of directional pixels in the plurality of waveguides provide a plurality of pictures that form a multi-view 3D image. The multi-view 3D image can be generated by a directional beam emitted by a directional pixel in the backlight Multi-view 3D images of red, blue and green.

It should be understood that in the following description, numerous specific details are set forth However, it should be understood that such examples may be practiced without limitation to these specific details. In other instances, well-known methods and structures may not be described in detail to avoid unnecessarily obscuring the description of the examples. Moreover, such examples can be used in conjunction with each other.

Referring now to Figure 1, a schematic diagram of a top view of a waveguide-based directional backlight having an integrated hybrid laser according to various examples is depicted. Directional backlight 100 includes hybrid lasers 105a-d disposed in substrate 110 to produce collimated input planar beams 115a-d and 120a-d for waveguide arrays composed of waveguides 125a-d. When referred to herein in a timely manner, a planar beam means a beam of light that is substantially parallel to each other. The hybrid lasers 105a-d can be, for example, mixed enamel annular lasers (described in more detail below with respect to FIG. 4) and disposed on the substrate 110 to couple to each waveguide. Each mixed enamel ring laser can be used to produce a given color of light. For example, the mixed enamel laser 105a may be a red laser, the mixed enamel laser 105b may be a green laser, the mixed enamel laser 105c may be a blue laser, and the mixed enamel laser 105d may be For a white laser.

The waveguides 125a-d can be dielectric or polymer waveguides having a plurality of directional pixel elements disposed thereon, such as directional pixels 130a-d disposed on the waveguide 125a. The directional pixels 130a-d scatter portions of the input planar beams 115a-d and 120a-d into output directional beams 135a-d. In various examples, each directional element 130a-d has a patterning grating of substantially parallel grooves, such as grooves 140a for directional elements 130a. The groove thickness of the grating can be substantially The same, resulting in a substantially flat design. The trenches may be etched in the waveguide or comprised of a material deposited on top of the waveguide (eg, any material that may be deposited and etched or removed, including any dielectric or metal).

Each directional beam 135a-d has a given direction and angular spread determined by the patterned grating in its corresponding directional pixels 130a-d. In particular, the direction of each directional beam 135a-d is determined by the orientation of the patterned grating and the grating pitch. The angular spread of each directional beam is determined by the length and width of the grating of the patterned grating. For example, the direction of the directional beam 135a is determined by the orientation of the patterned grating 140a and the grating pitch.

It is understood that such a substantially planar design and the formation of directional beams 135a-d based on input planar beams 115a-d, 120a-d require a grating having a substantially smaller pitch than conventional diffraction gratings. For example, conventional diffraction gratings scatter light by propagating a beam of light that substantially traverses the plane of the grating. Here, the grating in each of the directional pixels 130a-d is substantially on the same plane as the input planar beams 115a-d, 120a-d when the directional beams 135a-d are generated. This planar design makes it possible to illuminate with a hybrid laser 105a-d.

In various examples, the directional beams 135a-d are precisely controlled by the grating properties in the directional pixels 130a-d comprising a grating length L , a grating width W , a groove orientation θ, and a grating pitch Λ. In particular, the grating length L of the grating 140a controls the angular spread ΔΘ of the directional light beam 135a along the propagation axis of the input light, and the grating width W controls the angle of the directional light beam 135a transverse to the propagation axis of the input light. The degree of development △ Θ, the formula is as follows: Here λ is the wavelength of the directional beam 135a. The orientation of the groove specified by the grating azimuth angle θ, and the grating pitch or period specified by Λ, control the direction of the directional beam 135a.

The grating length L and the grating width W may vary in the range of 0.1 to 200 μm in size. The groove azimuth angle θ and the grating pitch Λ can be set to satisfy a desired direction of one of the directional beams 135a, wherein, for example, the groove azimuth angle θ is on the order of -40 to +40 degrees, and the grating pitch is at 200- 700nm grade.

It will be appreciated that the directional backlight 100 is shown for illustrative purposes only as one of the four waveguides 125a-d. A directional backlight according to various examples can be designed to have many of the described waveguide arrays (eg, more than 100) depending on how the directional backlight 100 is used (eg, for 3D display screens, 3D watches, mobile devices) Wait). It should also be appreciated that the directional pixels can have any shape including, for example, a circle, an ellipse, a polygon, or other geometric shapes.

2A-B are schematic diagrams showing a top view of a waveguide-based directional backlight having an integrated hybrid laser in accordance with various other examples. In FIG. 2A, directional backlight 200 has hybrid lasers 205a-d that join substrate 210 to be positioned between each waveguide. In FIG. 2B, directional backlight 215 has hybrid lasers 220a-d that join substrate 225 to be adjacent the bottom of each waveguide. The hybrid lasers 220a-d are also shown as being non-aligned relative to the axis 230 passing through the substrate 225. It will be understood by those skilled in the art that various other combinations of integrated lasers disposed in a substrate coupled to a waveguide layer can be devised without departing from the principles described herein. For example, a hybrid laser can be disposed in the substrate to Located on the top or bottom of the waveguide.

Attention is now directed to Figure 3, which shows different top and side cross-sectional views of a directional backlight according to various examples. The top view 300 shows a hybrid laser 305 disposed in the substrate 310 and joining the waveguides 315. Side view 320 shows a cross-sectional side view of a directional backlight, such as directional backlights 100, 200, and 215. The hybrid laser 325 is comprised of an active material (e.g., a III-V semiconductor material) disposed on a ruthenium/iridium oxide substrate comprised of a tantalum layer 335 and a tantalum oxide layer 330. The tantalum oxide layer 330 provides a good cladding material for the waveguide 340.

A hybrid laser is described in more detail in Figure 4. The hybrid laser 400 is bonded to one of the III-IV family of quantum well regions 405 via the nitride layer 415. The optical waveguide 420 is defined by two grooves in the tantalum/niobium oxide layer 410 such that the hybrid laser 400 behaves like an inverted ridge waveguide. Because the III-V region 405 is a mixed germanium (eg, indium phosphide ("InP") and aluminum gallium indium arsenide ("AlGaInAs")), III-V layer 405 and germanium/antimony oxide layer 410 The links between the two are automatically aligned, and the links between them do not require an alignment step. Since the optical mode of the hybrid laser 400 overlaps the III-V material 405 and the enamel waveguide 420, the electrical pump gain can be obtained from the III-V active region 405.

As understood by those skilled in the art, hybrid laser 400 is but one example of a hybrid laser that can be integrated into one of the waveguide layers in a directional backlight. Other types of hybrid lasers can be used, such as distributed feedback lasers. Referring now to Figure 5, a directional backlight using a distributed feedback type of laser is described. The directional backlight 500 includes a distributed feedback type disposed in the substrate 510 Lasers ("DFB") 505a-d are used to generate collimated input planar beams 515a-d and 520a-d for use in a waveguide array of waveguides 525a-d. The waveguides 525a-d can be dielectric or polymer waveguides having a plurality of directional pixel elements disposed thereon, such as directional elements 530a-d disposed on the waveguide 525a. Directional pixels 530a-d scatter portions of input plane beams 515a-d and 520a-d into an output directional beam 535a having a direction and angular spread that are precisely controlled by a plurality of properties of directional pixels 530a-d. d.

6 shows a different top and side cross-sectional view of the directional backlight of FIG. 5 in accordance with various examples. Top view 600 shows a DFB laser 605 disposed in substrate 610 and coupled to waveguide 615 having directional pixels 620a-b. Side view 625 shows a cross-sectional side view of one of the directional backlights of FIG. The DFB laser 630 is formed of an active material (e.g., a III-V semiconductor material) disposed on a tantalum/niobium oxide substrate formed on the tantalum layer 640 and the tantalum oxide layer 635. The tantalum oxide layer 635 provides a good cladding material for a waveguide having directional pixels 645a-b.

It should be understood that the various examples shown in Figures 1-7 illustrate various ways of directly integrating light into a waveguide layer. Having a light source (e.g., a plurality of hybrid ring lasers as shown in Figures 1-4 and a DFB laser shown in Figures 5-6) that are readily fabricated with a waveguide layer comprising a plurality of directional elements as described above. Other examples of the target are also feasible.

While the examples in Figures 1-6 are shown in a two-dimensional version, Figure 7 shows an exemplary 3D view of a directional backlight 700 having hybrid lasers 705a-d disposed in a substrate 710 coupled to waveguides 715a-d. . The hybrid lasers 705a-d produce a plurality of input plane beams (illustrated by arrow symbols in the figure), the plurality of inputs The planar beam is scattered into a directional beam having precisely controlled one direction and angular spread of directional elements in the waveguides 715a-d (e.g., directional elements 720a in the waveguide 715a).

As understood by those skilled in the art, each directional pixel can have different properties (e.g., pitch, orientation, grating length, raster width, etc.). Referring now to Figure 8, a 3D view of an example directional backlight is depicted. Backlight 800 shows a waveguide array having waveguides 805a-c. Each waveguide has a plurality of directional pixel configurations thereon, such as directional pixel 810a in waveguide 805a, directional pixel 810b in waveguide 805b, and directional pixel 810c in waveguide 805c. The directional pixels 810a-c can be designed to have different grating pitches and orientations. Each directional pixel 810a-c receives an input planar beam (e.g., light beam 815a-c) from a hybrid laser and scatters the directional beam according to the grating pitch and orientation of each directional pixel. (eg, directional beams 820a-c). As described above, the directional beams 820a-c can thus generate a 3D image for a plurality of pictures. Each directional beam can be precisely controlled by the properties of its corresponding directional pixel.

Attention is now directed to Figures 9A-B, which illustrate a top view of a directional backlight in accordance with various examples. In Figure 9A, directional backlight 900 is shown with hybrid lasers 905a-d that produce input planar beams 910a-d and 915a-d, and waveguides 920a-d that are comprised of a plurality of polygonal directional elements disposed thereon ( These pixels are, for example, directional pixels 925 in the waveguide 920a. Each directional pixel is capable of scattering a portion of the input planar beam into an output directional beam (eg, a directional beam 930 scattered by directional pixels 925). Multiple directional beams scattered by all of the directional elements in the waveguides 920a-d can present multiple images In the face, these pictures combine to form a 3D image, such as a 3D image 935.

Similarly, in FIG. 9B, directional backlight 940 is shown having a hybrid laser 945a-d that produces input planar beams 950a-d and 955a-d, and a waveguide 960a that is comprised of a plurality of polygonal directional elements disposed thereon. -d (such pixels are, for example, directional pixels 965 in waveguide 960a). Each directional pixel is capable of scattering a portion of the input planar beam into an output directional beam (e.g., directional beam 970 scattered by directional pixels 965). The directional beam scattered by all of the directional elements in the waveguides 960a-d can present a plurality of image frames that, when combined, form a 3D image, such as a 3D image 975.

In various examples, the waveguides in a waveguide array can be designed to have geometrically distinct regions. Each geometrically distinct region has a directional pixel that is perpendicular to the orientation of the region, thereby enabling the directional beam to have a different vertical orientation in each region. Figure 10 shows an example of a waveguide having a plurality of geometrically distinct regions. The waveguide 1000 has geometrically distinct waveguide regions 1005a-1005e. Each waveguide region can have a single horizontal section, such as waveguide region 1005a, or a plurality of segments having different orientations, such as waveguide regions 1005b-e. The waveguide region 1005b-e has an angular section disposed between the two horizontally oriented sections. For example, the waveguide region 1005e has an angular section 1010 disposed between the horizontal sections 1015a-b.

Each waveguide region has a single directional pixel disposed thereon, such as directional pixels 1020a-e. The directional pixels 1020a-e placed in each waveguide region are oriented perpendicular to the orientation of the regions shown in the figures. In the case of a waveguide region (e.g., region 1005b-e) having an angular segment between the two horizontal segments, the directional pixels (e.g., pixels 1020b-e) are perpendicular to the The orientation of the angular section. This allows the directional beam scattered by each directional element to have a different vertical orientation in each region.

Attention is now directed to Fig. 11, which is a schematic illustration of a directional backlight having a plurality of waveguide arrays including the waveguide of Fig. 10. The directional backlight 1100 is shown as having a waveguide layer comprising a plurality of waveguide arrays 1105a-c. Each waveguide array has four waveguides (for example, one for red light, one for green light, one for blue light, and the other for white light), and the waveguides are disposed on a substrate 1115 bonded to the waveguide layer. Multiple integrated lasers (eg hybrid laser 1120). The waveguide arrays 1105a-c can be designed to form different viewing sections, such as for example viewing section 1110. Each viewing section can be designed to scatter a directional beam into a given image frame to produce a directional image of a 3D image.

A flow chart for generating a 3D image using a directional backlight in accordance with various examples is illustrated in FIG. First, the nature of the directional pixels of the directional backlight is specified (step 1200). This property may include the characteristics of a patterned raster in a directional pixel, such as raster length, raster width, orientation, pitch, and duty cycle. As described above, each directional pixel in the directional backlight can be designated to have a given set of properties to produce a directional beam having a direction and angular spread that is precisely controlled according to such properties. Second, the directional backlight is fabricated to have a plurality of directional pixels disposed over the plurality of waveguides (step 1205). The waveguides can be dielectric or polymer waveguides and the like. The directional pixels may be etched in the waveguide or formed by a patterned grating having a material deposited on top of the waveguide (the material being, for example, any material that may be deposited and etched or removed, including any dielectric or metal ). In many cases, the waveguide can also have geometric differences as shown in Figure 10-11. region. Light from a plurality of hybrid lasers disposed in a substrate connecting the plurality of waveguides is input into the directional backlight in the form of an input planar beam (step 1210). Finally, a 3D image is generated from a directional beam of light scattered by the directional pixels in the directional backlight (step 1215).

Advantageously, the precise control achieved by the directional pixels in the directional backlight enables a 3D image to be produced while making it easy to fabricate a substantially planar structure. Different configurations of directional pixels can produce different 3D images. The directional backlights described herein can be used to provide 3D images in a display screen (such as televisions, mobile devices, tablets, video game devices, and the like), and such as 3D watches, 3D art devices, 3D. 3D images are provided in other applications such as medical devices.

It is to be understood that the foregoing description of the disclosed examples is provided to enable any skilled person to make or use the invention. A variety of modifications to the examples are readily apparent to those skilled in the art, and the broad principles defined herein may be applied to other examples without departing from the spirit or scope of the invention. Therefore, the invention of the present application is not intended to be limited to the examples shown herein, but the broadest scope of the principles and novel features disclosed herein.

100‧‧‧ Directional backlight

105a-d‧‧‧Hybrid laser

110‧‧‧Base

115a-d, 120a-d‧‧‧ plane beam

125a-d‧‧‧Band

130a-d‧‧‧ directional pixels

135a-d‧‧‧Directional beam

Claims (16)

A directional waveguide-based backlight for use in a multi-view display screen having an integrated hybrid laser comprising: a waveguide layer having a plurality of waveguide arrays, each waveguide array having a set of waveguides, each waveguide Having a plurality of directional pixels to scatter a plurality of input plane beams into a plurality of directional beams, each directional beam having a direction controlled by the properties of one of the plurality of directional pixels An angular spread; and a plurality of hybrid lasers disposed to provide the plurality of input plane beams in a substrate coupled to the waveguide layer. The directional waveguide-based backlight of claim 1, wherein the plurality of hybrid lasers comprise a hybrid laser selected from the group consisting of a hybrid annular laser and a hybrid distributed feedback laser. The directional waveguide based backlight of claim 1, wherein the plurality of waveguide arrays are substantially planar. The directional waveguide based backlight of claim 1, wherein each of the plurality of directional pixels comprises a plurality of patterned gratings having a plurality of substantially parallel and inclined grooves. The directional waveguide based backlight of claim 4, wherein the properties of a directional pixel include a grating length, a grating width, a grating orientation, a grating pitch, and a duty cycle. The backlight of the directional waveguide according to claim 5, wherein a pitch and azimuth control of a directional pixel is directional by the directional pixel scattering The direction of the beam. The directional waveguide based backlight of claim 6, wherein the length and width of a directional pixel control the angular spread of a directional beam by a directional element. A directional waveguide based backlight of claim 1, wherein one of the set of waveguides comprises a plurality of geometrically distinct regions, each region having a plurality of segments and a single directional pixel. A method for generating a multi-view 3D image using a waveguide-based directional backlight having a plurality of integrated lasers, the method comprising: assigning a plurality of properties to each of the plurality of directional pixels, each directional image The element is formed by a patterned grating having substantially parallel and inclined grooves; manufacturing a directional backlight having one of the plurality of directional pixels disposed on the plurality of waveguides; And a plurality of mixed laser light from the plurality of waveguides illuminate the plurality of waveguides; and using the directional light beams scattered by the plurality of directional pixels in the directional backlight to generate the multi-view image . The method of claim 9, wherein each directional beam is controlled by the properties of a directional cell. The method of claim 10, wherein the properties of a directional cell comprise a raster length, a raster width, a raster orientation, a grating pitch, and a duty cycle. The method of claim 11, wherein the pitch and orientation of a directional cell control the direction of the directional beam of the directional cell. The method of claim 11, wherein the length and width of a directional cell control the angular spread of the directional beam of the directional cell. The method of claim 11, wherein fabricating a directional backlight comprises fabricating a waveguide having a plurality of geometrically distinct regions, each region having a plurality of segments and a single directional pixel. A waveguide comprising: a plurality of geometrically distinct regions, each region having a plurality of segments; and a plurality of directional pixels disposed on the plurality of geometrically distinct regions for scattering a plurality of input plane beams into a plurality of a directional beam, each directional beam having a direction and an angular spread controlled by a plurality of properties of one of the plurality of directional pixels; wherein the input plane beams are arranged A plurality of hybrid lasers coupled to one of the substrates of the waveguide are produced. The waveguide of claim 15 wherein the plurality of segments comprise an angular section disposed between the two horizontally oriented segments.