A 128-view auto-stereoscopic display using laser-scan and angle-magnifying screen is proposed. On the exit pupil of front projection lens, 8 spots of laser-scanning are provided. The exit pupil of the rear projection lens is doubled by two aperture-relay lenses and 8 spots of laser-scanning are doubled to 16 spots. The angle-magnifying screen comprises the main part of double-lenticular and the attaching part of micro-deflector. With the micro-deflector, angles formed by the laser scanning are deflected into eight angle ranges. With the double-lenticular, eight angle ranges incident into the screen are magnified into a large field of view for the observer. The laser scanning is realized by the vibration of Galvano-mirror that synchronizing with the frame rate of the DMD. For one cycle of vibration by the Galvo-mirror, 16 steps of reflections happen on going and returning paths. For each viewing position, 48 viewing per second are provided. The micro-deflector part comprises the (-4, +4) vertical micro-deflector and the (-1, -1, +1, +3) 45° micro-deflector. Each elements of the micro-deflector are aligned with the images of the pixels that come from the DMD. When a scanning of 16 spots passes different deflecting elements that cover 8 different pixels, the scanning is deflected to eight angle ranges and 128 partitioned viewing zones are formed in the observer plane.
A 30-view auto-stereoscopic display using angle-magnifying screen is proposed. Small incident angle of Lamp-scanning from exit pupil of projection lens is magnified into large field of view on the observing side. The lamp-scanning is realized by the vibration of Galvano-mirror that synchronizing with the frame rate of the DMD and reflecting the laser illuminator to the scanning angles. To achieve 15-view, a 3-chip DLP projector with frame rate of 720 Hz is used. For one cycle of vibration of Galvano-mirror, steps of 0, 2, 4, 6, 8 10, 12, 14 are reflected on going-path and steps of 13, 11, 9, 7, 5, 3, 1 are reflected on returning path. A frame is divided into two half parts of odd lines and even lines for two views. For each view, 48 half frames per second are provided. A projection lens with aperture-relay module is used to double the lens aperture and separating the frame into two half parts of even and odd lines. After going through the Philips prism, three panels, the scanning 15 spots are doubled to 30 spots and emerge from the exit pupil of the projection lens. The exit 30 light spots from the projection lens are projected to 30 viewing zones by the anglemagnifying screen. A cabinet of rear projection with two folded mirrors is used because a projection lens of long throw distance is required.
Light source for cinema projector requires reliability, high brightness, good color and 3D for without silver screens. To meet these requirements, a laser-phosphor based solid state illuminator with 6 primary colors is proposed. The six primary colors are divided into two groups and include colors of R1, R2, G1, G2, B1 and B2. Colors of B1, B2 and R2 come from lasers of wavelengths 440 nm, 465 nm and 639 nm. Color of G1 comes from G-phosphor pumped by B2 laser. Colors of G2 and R1 come from Y-phosphor pumped by B1 laser. Two groups of colors are combined by a multiband filter and working by alternately switching B1 and B2 lasers. The combined two sequences of three colors are sent to the 3-chip cinema projector and synchronized with frame rate of 120Hz. In 2D mode, the resulting 6 primary colors provide a very wide color gamut. In 3D mode, two groups of red, green and blue primary colors provide two groups of images that received by left and right eyes.
The head mount display for entertainment usually requires light weight. But in the professional application has more requirements. The image quality, field of view (FOV), color gamut, response and life time are considered items, too. A head mount display based on 1-chip TI DMD spatial light modulator is proposed. The multiple light sources and splitting images relay system are the major design tasks. The relay system images the object (DMD) into two image planes to crate binocular vision. The 0.65 inch 1080P DMD is adopted. The relay has a good performance which includes the doublet to reduce the chromatic aberration. Some spaces are reserved for placing the mirror and adjustable mechanism. The mirror splits the rays to the left and right image plane. These planes correspond to the eyepieces objects and image to eyes. A changeable mechanism provides the variable interpupillary distance (IPD). The folding optical path makes sure that the HMD center of gravity is close to the head and prevents the uncomfortable downward force being applied to head or orbit. Two RGB LED assemblies illuminate to the DMD in different angle. The light is highly collimated. The divergence angle is small enough such that one LED ray would only enters to the correct eyepiece. This switching is electronic controlled. There is no moving part to produce vibration and fast switch would be possible. Two LED synchronize with 3D video sync by a driving board which also controls the DMD. When the left eye image is displayed on DMD, the LED for left optical path turns on. Vice versa for right image and 3D scene is accomplished.
The current autostereoscopic projection system is accomplished by array projectors. It is easy to realize optically but
has a drawback with size. Another type is to place the shutter on the screen. It saves the volume but reduces the
efficiency depending on how many views are produced. The shutter in the lens aperture has the same efficiency
problem, too. To overcome these problems, a full HD autostereoscopic projector based on the lens aperture switching
type is proposed. It has RGB laser sources and can produce 16-views or even higher stereoscopic images.
This system removes the shutter in the lens aperture by the opti-mechanism itself. The specific light on the lens
aperture coming from the point on the DMD is reflected to different angles. The proper angle of light is generated in
the object side by the relay and folding system. The UHP lamps or the LED rays are difficult to constrain in a relative
small cone angle. For this reason, the laser is applied to the design. The very small etendue of the laser is good for
this architecture. The rays are combined by dichroic filter from RGB laser sources then forming and expanding to the
mirror. The mirror is synchronized with DMD by the DSP control system. The images of different views are
generated by DMD and specific position of the mirror. By the double lenticular screen, the lens aperture is imaged to
the observer’s viewing zone and the 3D scene is created.
A module of laser-phosphor based light source, wherein phosphor light pumped by laser is combined with blue laser
light to form white light, is used as light source for 3-chip projectors. Arrays of blue laser diodes are concentrated and
aligned by stripes of mirrors and formed into a laser bank. Laser lights of 445nm and 460 nm from two directions and
two half apertures are guided and converged into either red or green phosphors. Red and green lights emerge from two
spots of phosphors are collimated into two directions and reflected into one direction by two dichroic plates. Two
dichroic plates also reflect two directions of 445nm and 460 nm residual blue laser lights into one direction. The
combined red, blue and green lights are guided into one direction and can be used as input light source for 3-chip
A solid state light source provided for wavelength multiplex 3D Display is proposed. The system of solid state light
source includes blue laser arrays of two wavelengths, a 2-ring phosphor wheel, a multi-band filter and a TIR prism.
Green and red phosphors excited by blue lasers provide the original green and red lights of wide bandwidth. By passing
through or reflected by a multi-band filter, two groups of green and red lights of narrow bandwidth for left or right eyes
are selected. Blue lasers of two wavelengths also provide two blue lights for left and right eyes. Instead of using a second
rotated narrow band filters that synchronized with the first phosphor wheel, a wheel having two rings coated with mirrors
and phosphors is used to replace the synchronization existing in the conventional two wheels method. After passing the
2-ring wheel, the light source switches between two light paths that lead to be reflected or transmitting through the multiband
filter. The multi-band filter can be disposed in a telecentric optical path to secure a high efficiency for the filter. A
compact spectral multiplex light source is realized and can be directly attached to any existing optical engine.
We have designed and fabricated the low-polarizing X-plate to increase the luminous throughput for
LED projector. We calculate reflectivity characteristic of X-plate as a function of the wavelength at
different angles of incidence from air of unpolarized light. A new way to design filter to control the
title effect of thin film filters. The wavelength shift of the new design for reflected red filter and
reflected blue filter at the angle of 45° ± 8° is 16 nm and 14 nm, respectively.
We have designed and fabricated angle-selective filters to increase the luminous throughput of a blue light emitting diode
(LED) and its associated color wheel. The emission direction was tailored to increase the light emission in the useful
direction by using multilayer optical coating with alternating high and low refractive indices layers. The angle selective
filters limit the luminance angle to less than an acceptance angle of 30 degrees for green and red on the phosphors color
wheel. The filters increase the luminance efficiency by converging and recycling the light. The color performance of the
phosphors color wheel was improved and gave an advantage of energy saving in the LED projector.
A new x-cube prism with small polarizing dichroic filters was made for an optical projection system. The x-cube prism was used to combine the three primary colors, which were divided by the preset dichroic mirrors. A coating was designed and fabricated such that s- and p-polarized light was shifted to be obliquely incident in the x-cube prism: the shift was the same as that at the dividing dichroic mirrors. Hence, energy loss was lower than that associated with the conventional x-cube prism, and the brightness of the projection system was 33.2% higher and the color temperature was 18.2% higher than those of the conventional x-cube prism.
An optical design of digital light processing projector accommodating three pieces of micro digital mirror array display panels is presented. The system is configured by the combination of a color separation unit and a color re-combination prism, which combines light signals from individual display panels and then directs the synthesized full color images projected onto the screen. The color separation unit comprises two dichroic filters set at 40 degrees with respect to the optical axis of the system and two reflecting mirrors with relay lens for guiding light. The color re-combination unit is contructed in the form of a modified x-prism for better achievement of image contrast, color saturation, and light efficiency. The present system out-performs systems based on the configuration of Philips prism in less occurrence of degraded image quality associated with teh thermal influence of the optical engine, short optical path in prism and back focal length of the projection lens, and the physical size and weight of the unit. Comparisons in overall optical characteristics of the proposed system and those designed by means of various modules of single prism, which operates color separation and color combination processes along same optical path through the prism block will also be presented.