Optical: systems and elements – Single channel simultaneously to or from plural channels – By surface composed of lenticular elements
Reexamination Certificate
2000-05-01
2001-09-18
Epps, Georgia (Department: 2873)
Optical: systems and elements
Single channel simultaneously to or from plural channels
By surface composed of lenticular elements
C359S641000
Reexamination Certificate
active
06292300
ABSTRACT:
The present application is based on Korean Application No. 99-42595 filed on Oct. 4, 1999, herein incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for generating an independent coherent beam array from a single light source, and more particularly, to an apparatus for generating an independent coherent beam array in which beams are independently switched using 45-degree mirrors for recording and read-out operations.
2. Description of the Related Art
FIG. 1
illustrates a conventional coherent beam array adapted in a holographic memory, which has been suggested in U.S. Pat. No. 4,988,153. In the coherent beam array, a plurality of vertical cavity surface emitting laser (VCSEL) diodes
14
form a two-dimensional laser diode array
12
as a light source. An XY selector
16
allows for selective electrical activation of a single or several VCSEL diodes in sequence.
The output beam from the selected VCSEL diode is converted into a collimated beam by a collimating lens
20
. The position of the selected VCSEL diode, the X-Y coordinate of the selected VCSEL diode on the two-dimensional laser diode array
12
, causes a small change in the incident angle of the collimated beam upon a holographic recording medium
10
.
Images can be written to or read from the holographic recording medium
10
by collimated beams generated from the coherent beam array. During recording, an image
40
is presented on an image light source
42
and is recorded through a recording collimating lens
46
on the recording medium
10
. The writing angle &thgr;
W
between the collimated beams respectively from the collimating lens
42
and the recording collimating lens
46
, which are incident upon the recording medium
10
, is varied, which allows multiple independent images to be superimposed and sequentially written to the recording medium
10
. Although not illustrated, during reading, images recorded on the recording medium
10
are read out only by the collimated beam, of which the incident angle upon the recording medium
10
for reading is the same as that of the reference collimated beam.
The coherent beam array generating apparatus having the above-mentioned configuration can be applied to holographic information storing devices or displays, for optical interconnections therein, which require several tens to several hundreds of light sources. The manufacture of the VCSEL
12
is technically difficult, particularly in controlling the heat generated from laser diodes thereof and in maintaining the uniformity in the intensity of laser beams as well as the irradiation angle of the laser beams, which increases the manufacturing cost and produces a low yield.
SUMMARY OF THE INVENTION
To solve the above problems, it is an object of the present invention to provide an apparatus for generating an independent coherent beam array from a single light source, in which coherent beams can be independently activated using 45-degree mirrors for recording and read-out operations.
The above object of the present invention is achieved by an apparatus for generating an independent coherent beam array using 45-degree mirrors, comprising: a single light source; a collimating lens for collimating the beam emanated from the light source; a first mirror array having a plurality of rotatable micro mirrors vertically positioned linearly on an optical path of the collimated beam from the collimating lens, for reflecting the collimated beam from the collimating lens by 90 degrees; and a second mirror array having a plurality of 45-degree rotatable micro mirrors laid flat on the same plane with the first mirror array, a predetermined number of 45-degree rotatable micro mirrors of the second mirror array being positioned in a row for each micro mirror of the first mirror array, for reflecting the collimated beam reflected by the first mirror array at a right angle to the optical path of the collimated beam reflected by the first mirror array.
Preferably, the light source is a laser diode, a light emitting diode, or a light beam guided by an optical fiber.
In another embodiment, the first mirror array may have a plurality of micro mirrors positioned linearly at an angle of 45 degrees with respect to the optical path of the collimated beam from the collimating lens, beside the optical path of the collimated beam from the collimated lens, the micro mirrors being movable toward the second mirror array to reflect the collimated beam from the collimating lens by 90 degrees toward the second mirror array.
Preferably, individual micro mirrors of the second mirror array are rotatable by 45 degrees. Preferably, individual micro mirrors of the first and second mirror arrays are turned on at 45 degrees to the corresponding optical path and are turned off at 0 degrees to the corresponding optical path.
REFERENCES:
patent: 3989890 (1976-11-01), Nathanson
patent: 4988153 (1991-01-01), Paek
patent: 5729386 (1998-03-01), Hwang
patent: 5748172 (1998-05-01), Song
patent: 5818627 (1998-10-01), Perlo
Kim Ji-deog
Lee In Young
Lee Suk-han
Burns Doane Swecker & Mathis L.L.P.
Epps Georgia
O'Neill Gary
Samsung Electronics Co,. Ltd.
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