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HOLOGRAMS. By: Sara S. Hassen Mobile Media 29 th March 2012. The history of Holograms. Holography is creating a special photographic image Hologram is a photographic recording of the image Dennis Gabor invented in 1948 Nobel Prize for Physics in 1971.
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HOLOGRAMS By: Sara S. Hassen Mobile Media 29th March 2012
The history of Holograms • Holography is creating a special photographic image • Hologram is a • photographic recording • of the image • Dennis Gabor • invented in 1948 • Nobel Prize for Physics • in 1971. • In 1962, Emmett N. Leith and JurisUpatnieks
How does it work??? It’s genius! • A photographic image is variation of intensity of reflected light. • Holography reconstructs the appearance of an object by recording the phase and amplitude of reflected light waves of a laser beam.
Two types of laser beams in holography • Continuous-wave laser holography 2. Pulsed-laser photography
The object is hit with laser light. The data is recorded onto a plate by capturing the reflected, diffracted and scattered light. The plate acts as a diffraction grating. When hit with a laser beam, it again diffracts light in the same angle. The image then appears pseudoscopic. Repeating the process will allow reconstruction of the original image. Continuous-wave laser holography
Holograms so far Have appeared in news and entertainment
Projectorsprecursors to holography? How Does a Projector Work? The projection system has an optical semiconductor known as the DLP chip with up to 2 million microscopic mirrors The mirrors are directed by the semiconductor, to reflect greyscale light To give color, the mirrors are modified to reflect back only certain colors of light
Basics of Projectors • the white light generated by the lamp passes through a prism that divides it into red, green and blue. • Each DLP chip is identified for each of these three colors • the colored light that the micromirrors reflect is combined and passed through the projection lens to form an image.
Samsung Galaxy SII • Android 2.3 OS • 480x800 screen • 8.0 mega-pixel camera • 3.7 inch WVGA Super AMOLED display • Texas Instruments DLP Pico Projector
Four main parts • the electronics system, • a laser light source, • a combiner optic • scanning mirrors.
More on the Pico Projector Minus: • dimmed setting • low resolution • short distance between the surface and the projector • white background Plus: • Long life, as opposed to a lamp projector
Uses of a projector (on a phone) • In business or other presentations • To make mass sharing possible • What else can you think of?
The End • Thank you for listening!