U.S. patent application number 10/695134 was filed with the patent office on 2004-05-06 for projection of laser generated image.
Invention is credited to Butler, Andrew G., Carlsen, William F. JR., Duval, Eugene F., Tacklind, Christopher A., Zimmerman, Thomas.
Application Number | 20040085646 10/695134 |
Document ID | / |
Family ID | 27384578 |
Filed Date | 2004-05-06 |
United States Patent
Application |
20040085646 |
Kind Code |
A1 |
Tacklind, Christopher A. ;
et al. |
May 6, 2004 |
Projection of laser generated image
Abstract
A multi-beam tool is disclosed which can perform square, plumb,
and level function which may be required in a construction
environment. The tool can generate in a preferred embodiment up to
five orthogonal beams with two beams being plumb and three beams
being leveled. Combinations of two level beams, or a level and a
plumb beam in orthogonal arrangement can produce a square alignment
set of beams. The tool includes in a preferred arrangement a
self-leveling pendulum to which a laser and quad-mirror arrangement
is secured. The self-leveling pendulum is dampened in order to
allow the tool to settle down and provide alignment after the tool
is positioned as desired.
Inventors: |
Tacklind, Christopher A.;
(Mountain View, CA) ; Carlsen, William F. JR.;
(Mountain View, CA) ; Duval, Eugene F.; (Mountain
View, CA) ; Butler, Andrew G.; (Mountain View,
CA) ; Zimmerman, Thomas; (Mountain View, CA) |
Correspondence
Address: |
FENWICK & WEST LLP
SILICON VALLEY CENTER
801 CALIFORNIA STREET
MOUNTAIN VIEW
CA
94041
US
|
Family ID: |
27384578 |
Appl. No.: |
10/695134 |
Filed: |
October 27, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10695134 |
Oct 27, 2003 |
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10353599 |
Jan 28, 2003 |
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6657788 |
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10353599 |
Jan 28, 2003 |
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09571482 |
May 16, 2000 |
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6542304 |
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60134403 |
May 17, 1999 |
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60159524 |
Oct 15, 1999 |
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Current U.S.
Class: |
359/629 |
Current CPC
Class: |
G02B 27/144 20130101;
G01C 15/004 20130101; G02B 27/106 20130101; G02B 27/648 20130101;
G02B 27/1073 20130101; G02B 27/1093 20130101; G02B 27/143
20130101 |
Class at
Publication: |
359/629 |
International
Class: |
G02B 027/14 |
Claims
What is claimed is:
1. A method for using a laser alignment device to project a laser
generated image at a distance, the method comprising: providing a
laser source to produce a beam of laser radiation; and positioning
a transmission mask in the path of the beam to modify the shape of
the transmitted beam.
2. The method of claim 1 wherein the transmission mask has a
substantially opaque region, and a substantially translucent region
in the shape of an image.
3. The method of claim 2 wherein the mask contains an aperture
within the substantially translucent region.
4. The method of claim 1 wherein the transmission mask is formed
from a holographic film.
5. The method of claim 4 wherein the transmission mask contains a
holographic image within the holographic film.
6. The method of claim 5 wherein the transmission mask contains an
aperture in the holographic film within the holographic image.
7. The method of claim 1 further comprising positioning a
reflective element in the path of the beam of laser radiation to
produce one or more laterally reflected beams.
8. The method of claim 7 wherein the transmission mask is
positioned in the path of a laterally reflected beam.
9. An apparatus for use with a laser alignment device for
projecting a laser generated image at a distance, comprising: a
laser source to produce a beam of laser radiation; and a
transmission mask, positioned in the path of the beam, to modify
the shape of the transmitted beam.
10. The apparatus of claim 9 wherein the transmission mask has a
substantially opaque region and a substantially translucent region,
the translucent region on the shape of an image.
11. The apparatus of claim 10 wherein the mask contains an aperture
within the substantially translucent region.
12. The apparatus of claim 9 wherein the transmission mask is
formed from a holographic film.
13. The apparatus of claim 9 wherein the transmission mask contains
a holographic image within the holographic film.
14. The apparatus of claim 13 wherein the transmission mask
contains an aperture in the holographic film within the holographic
image.
15. The apparatus of claim 9 further comprising a unitary
reflective element positioned in the path of the beam to produce a
plurality of beams, the reflective element defining a central
aperture, at least two substantially planar reflective surfaces
positioned around the central aperture for creating laterally
reflected beams from the beam of laser radiation, and other
sections located in-between the substantially planar reflective
surfaces such that the substantially planar reflective surfaces are
not adjacent one another.
16. The apparatus of claim 15 wherein the transmission mask is
positioned in the path of a laterally reflected beam.
17. The apparatus of claim 15 wherein the planar surfaces have
elliptical cross sections.
18. The apparatus of claim 15 wherein at least one of the
reflective surfaces has a largest cross section than a second of
the reflective surfaces.
19. The apparatus of claim 9 further comprising a reflective
element positioned in the path of the beam to produce at least one
laterally reflected beam.
20. The apparatus of claim 9 further comprising a quad-mirror
having reflective surfaces and an aperture extending through the
center of the quad-mirror.
21. The apparatus of claim 9 further comprising a collimating lens
and an enclosure of deformable material, wherein the lens and laser
source are at least partially positioned within the enclosure and
the lens is positioned in the path of the beam of laser
radiation.
22. The apparatus of claim 21 wherein the enclosure may be
symmetrically deformed to modify the distance between the lens and
the laser source.
23. The apparatus of claim 21 further comprising a reflective
element positioned within the enclosure of deformable material in
the path of the collimated beam to produce at least one laterally
reflected beam.
24. The apparatus of claim 23 wherein the enclosure of deformable
material further comprises holes in the enclosure to allow passage
of laterally reflected beams.
25. The apparatus of claim 23 wherein the enclosure of deformable
material may be asymmetrically deformed to rotationally deflect the
reflective element relative to the collimated beam.
26. The apparatus of claim 9, further comprising a gimbal-mounted
pendulum allowing for substantially pendular motion relative to an
axis of rotation, wherein the laser source is mounted on the
pendulum.
27. The apparatus of claim 9, further comprising a conductive
spring that provides power to the apparatus and a pendulum, wherein
the apparatus is hung from the pendulum.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is continuation of U.S. patent application
Ser. No. 10/353,599 filed Jan. 28, 2003, which is a divisional of
U.S. Pat. No. 6,542,304, filed May 16, 2000, which claims the
benefit of U.S. Provisional Application No. 60/134,403 filed May
17, 1999 entitled Self-Leveling Penta Laser Beam Device, and of
U.S. Provisional Application No. 60/159,524, filed Oct. 15, 1999,
entitled Self-Leveling Penta Laser Beam Device. All of these
applications are incorporated herein by reference.
[0002] Additional References
[0003] Reference is made to U.S. Pat. No. 5,680,208, issued Oct.
21, 1997, entitled GRAVITY ORIENTED LASER SCANNER, which is
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0004] In many instances it is desired to establish reference
lines. This is particularly useful for construction, grading, and
"do it yourself" activities. Traditional tools for these tasks
include straight edges, rulers, protractors, squares, levels, and
plumb bobs. More modern tools include laser alignment devices.
[0005] Laser alignment devices include simple pointers, pointers
with a bubble vial, self-leveling pointers, multiple beam pointers,
and devices that produce a sheet of light. It is highly desirable
to have multiple beams that are mutually orthogonal. This is
typically achieved by several partially silvered mirrors at 45
degrees to the laser beam. This method requires placing the mirrors
in precise alignment and securing them with glue. Further, the
mirrors should be extremely stable over time and temperature. More
beams require more mirrors at added expense and complexity.
SUMMARY OF THE INVENTION
[0006] The present invention relates to improvements to this field
rendering simpler, more stable and cost effective laser devices
which can generate one or more laser beams for measuring, aligning,
leveling and other purposes.
BRIEF DESCRIPTION OF THE FIGURES
[0007] FIG. 1 is a perspective view of an embodiment of a penta
beam splitter of the invention.
[0008] FIG. 2 is a perspective view of another embodiment of a beam
splitter of the invention.
[0009] FIG. 3 is a further embodiment of the invention which can be
used to project a pattern such as a pattern of cross hairs.
[0010] FIGS. 4a and 4b are perspective and side sectional views of
yet another embodiment of the invention that allows for steering
beams which are at angles with respect to the main laser
source.
[0011] FIG. 5 is a side sectional view of yet another embodiment of
the invention wherein the main laser beam can be focused by
symmetrical crimping of the housing of the embodiment.
[0012] FIGS. 6a and 6b depict side sectional views of another
embodiment of the invention, showing how the laser assembly is
suspended by a bearing mount.
[0013] FIG. 7 is a perspective view of another embodiment of the
invention using elliptical reflective mirrors.
[0014] FIG. 8 depicts an interference target resulting from the use
of device of FIG. 7.
[0015] FIG. 9 is a perspective view of another embodiment of the
invention using square reflective mirrors.
[0016] FIGS. 10a and 10b depict interference targets resulting from
use of the device of FIG. 9.
[0017] FIG. 11 is a perspective view of another embodiment of the
invention using rectangular mirrors.
[0018] FIGS. 12a, 12b, 12c depict interference targets resulting
from use of the device of FIG. 11.
[0019] FIG. 13 is a side view of a pendulum laser mount with spring
compensation.
[0020] FIG. 14 is a side view similar to FIG. 13 which allows for
field calibrations.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0021] I. Penta Beam Splitter
[0022] The present invention (FIG. 1) achieves the much-desired
feature of producing a series of mutually orthogonal beams with a
single splitter. Further, the beams are mutually coincident, that
is, the beams all emanate from the same point.
[0023] The splitter in this embodiment is fabricated from a small
block or cylinder of aluminum 2. Other materials and fabrication
techniques can be otherwise employed. Four reflective mirror
surfaces 8a-8d are produced by a process known as "single point
diamond turning." This process is widely used to produce polygonal
mirrors for laser printers. In one particular embodiment of the
invention, four sections or portions 10a-10d of the collimated beam
9 are reflected from the mirror surfaces. A fifth portion of the
light 12 passes directly through a hole 14 in the center of the
block.
[0024] The angle of the mirrors must be precisely 45 degrees to the
incident beam and have precise rotational symmetry. This is readily
achieved by optical tooling fixtures.
[0025] In this embodiment, light from laser diode 4 is directed
through a lens and collimator 6. This collimated light is directed
at mirror block 2.
[0026] In another embodiment, a similar effect could be achieved by
use of a refractive device that employs total internal reflection
or refraction to produce a 90 degree bend. A small flat portion is
created on the tip of the device closest to the incoming beam to
allow part of the beam to pass through undeflected, producing a
fifth beam.
[0027] II. Beam and Disk Splitter
[0028] A related feature can be achieved by using a conical surface
16 and hole 14 as depicted in the embodiment of FIG. 2. This
produces a plane or disk of laser light 18, together with an
orthogonal laser spot.
[0029] Various embodiments of the invention may include a multiple
faceted reflective device or devices having a mix of cylindrical
and faceted areas. For example, a device having twenty-four facets
would yield 24 beams or spots, each separated from its nearest
neighbor by an angle of 15 degrees. Larger areas could be used for
four of the facets, which would make those four reflected beams
brighter relative to the others. This is useful in marking the
major axes.
[0030] III. Cross Hair Projection
[0031] At short distances the beam may be too bright to use to
easily center upon a reference line or point. In an embodiment of
the invention as depicted in FIG. 3, a masking element such as a
holographic film 24, positioned on one or more of the laterally
reflected beams 22 (or beams 10a, b, c, d of FIG. 1) can be used to
project a more useful short range image such as a cross hair 28, or
a series of concentric circles. An aperture 26 in the mask allows
some light to pass through to be used at a distance.
[0032] Alternatively, in other embodiments, a similar effect may be
achieved by introducing intentional imperfections into the mirror
surfaces.
[0033] FIG. 3 is simplified by using a half-silvered mirror as a
beam splitter. Alternatively, the beam splitting FIG. 1 could be
used.
[0034] IV. Side Beam Steering
[0035] The four side beams produced by the embodiment of a penta
beam splitter of FIG. 1 are by design mutually perpendicular and
coplanar, the accuracy of which being determined by the accuracy of
the cutting process. But they may be thereafter aligned or adjusted
to be precisely perpendicular to the central beam. A traditional
approach would employ 4 set screws to precisely deflect the mirror
block.
[0036] A present embodiment of the invention (FIGS. 4a, 4b)
utilizes a novel approach to beam adjustment in mounting the laser
assembly within a cylindrical enclosure 30 of deformable material,
for example metal or plastic. The enclosure contains a series of
beam exit holes 36a-36d around its circumference to allow the
reflected beams exit the device. A web of deformable material
remains between the holes. The method of beam steering as embodied
in the invention works by crimping the web 34 formed between the
side exit holes. Deforming an adjacent pair of webs slightly
shortens the cylindrical structure in that local region. This
causes the beam to rotate back about this location. Crimping and
adjustments of the beam direction are noted by the angle .theta. in
FIG. 4a.
[0037] This method of beam adjusting has the significant benefit of
eliminating the need for glue, which aids in manufacturing and long
term stability.
[0038] V. Beam Focus by Symmetric Crimping
[0039] A technique similar to that of side beam steering described
above may be employed to focus the laser diode, as shown in the
embodiment of FIG. 5. In this embodiment another series of holes
38a-38d (holes 38c and 38d are not shown as they are in the
cut-away half of the enclosure) are introduced into the cylindrical
enclosure, this time between the laser source 4 and the lens 6. A
web 39 of material remains between the holes. Bending all four webs
the same amount causes the overall length of the section to
shorten. In practice, the diode may be pressed into the cylinder at
a distance just longer than nominal focal distance, and crimping
applied to shorten the diode/lens separation by an amount 40 until
the laser comes into focus. Typically, many metals have some
rebound after bending. This factor can be predicted and compensated
for by crimping past the focus point.
[0040] VI. Bearing Mount
[0041] A traditional means of producing a quality gimbal is with
two pairs of roller bearings. The pairs must be precisely located
and a preload must be applied to take out the clearance between the
bearings and races. An embodiment of the present invention (FIGS.
6a, 6b) reduces this to a single pair of bearings 47, 48 suspended
in a chain-like configuration. The slight angle .theta. shown on
the transverse beam 46 allows the weight of the pendulum 49, on
which the laser enclosure 30 is mounted, to be distributed over
both bearing units.
[0042] The pendulum arrangement shown in FIG. 6a and 6b is hung
from the double bearings 47, 48, and includes pendulum 49. Pendulum
49 mounts the laser enclosure 40 which can include the laser
enclosure depicted in FIGS. 1 and 2 by way of example. The
enclosure of FIG. 1 with the quad-mirror is preferable. Still
preferable, as is described more fully hereinbelow would be the
quad-mirror shown in FIGS. 9 or 11.
[0043] FIG. 6a is a cross-sectional view of the upper bearing 47
shown in FIG. 6b. The lower bearing 48 is mounted on a pin 46 which
extends at an angle from the pendulum body 49. It is in this way
that the lower bearings 48 hangs down from the upper bearings 47,
and the pendulum 49 hands down from the lower bearings 48. At the
base of the pendulum is the damping weight 44. The damping weight
44 is generally comprised of a conductor and in particular, a
copper conductor. In order for dampening to occur, a magnet
arrangement 45 is depicted. In a preferred embodiment, the magnet
arrangement includes a soft iron horseshoe-shaped mount 46 which
extends around the back side of the damping weight 44. Two magnets,
such as magnet 51, are mounted at the ends of the horseshoe 46. The
horseshoe provides a return path for the magnetic flux in order to
assist and concentrating the magnetic field between the front faces
of the magnets 51 in order to more efficiently damp the damping
weight 44. It is to be understood that in a preferred embodiment, a
magnetic arrangement of 45 would be placed on each side of the
damping weight. The damping weight would swing through the
arrangements and be damped by both magnetic arrangements 45.
[0044] VII. Round Mirrors 54
[0045] The shape of the laser spot is of considerable interest. The
practical need is to be able to identify and mark the center of the
spot. In a squaring or plumb application this needs to be done in
two axes. To facilitate this, a natural choice is round spots. The
following describes a novel method of producing them. It involves
die casting the quad mirror, previously described, in aluminum. A
feature of the device is four small posts 56a-56d surrounding a
central hole 58 (FIG. 7). The end of each post is single point
diamond turned to produce four elliptical mirrors. The axial
projection of each mirror is a circle. Thus, they act as apertures
to project circular shafts of light in each of 4 directions.
[0046] Round Spots Resulting From Round Mirrors
[0047] The smaller the circular apertures 56a-56d, the larger the
laser spots appear at a distance. This is due to the normal
dispersion of light off of a sharp aperture. Since the laser light
is monochromatic, the wave front from one side of the aperture
interferes with the wave front from the other side. This results in
a series of circular interference rings 59 (FIG. 8). The exact size
and diameter of the central spot 60 from hole 58 and these rings 59
depends on the wavelength, distance to the target, and the aperture
diameter. Apertures in the range of 2 mm produce acceptable
spots.
[0048] VIII. Square Mirrors 60
[0049] A novel alternative to the pyramidal mirror geometry
proposed in the above is to form four small mirrors into a
quad-mirror arrangement 60 with parallel sides (FIG. 9). This is
readily accomplished by forming the blank on a screw machine with a
special profile for the end cone. A square aperture 64 is readily
broached through the center. Four passes of a diamond-point
fly-cutter then cuts four mirrors 62a-62b leaving the conical
section in-between. In use, this presents five similar apertures to
the incident laser beam.
[0050] As can be seen in FIG. 9, the four mirrors meet each other
at common corners which define the central square aperture 64.
Corner 63a, b, c, and c, at the sides of the four mirrors 62a-62d,
do not go through the apex of the structure. In effect, the
structure is truncated in order to form the square aperture 64. The
truncated structure forms the square aperture 64 from which the
four mirrors 62a-62d emanate. Due to this structure, this
arrangement provides appropriate interference pattern so that
targets can be formed as described below.
[0051] Square Spots
[0052] The square central aperture produces a nominally square spot
(FIGS. 10a, 10b). As with the circular aperture, wave fronts from
opposite sides interfere, but in this case a series of spots are
formed radiating in four directions (FIG. 10a). This creates a
"cross hair" formation that is ideal for marking. The apertures
formed by the mirrors perform in a similar way. In the direction
where parallel edges are presented, interference spots are formed.
In the other direction, there in only one sharp edge (FIG. 10b).
The dispersion from this edge produces a "smear" along this axis.
It is similar in brightness and size to the string of spots in the
other direction. Thus a cross-hair appearance is produced.
[0053] IX. Rectangular Mirrors 68
[0054] The light from a laser diode is presented from a typical
collimating lens as a short line segment, in which the light is
spread out more along one cross-sectional axis than the other. In
one embodiment, to better slice up this beam, the mirrors 70a-70b
and 71a-71b need be all the same (FIG. 11). Of further design
consideration is the power distribution desired. For example, the
up and down beams may not be desired to be as strong as the side
beams, so the up and down reflectors may be designed to be smaller
than the lateral or sideways reflectors. A wide range of power
distributions is possible with minimal loss in the inter-mirror
space.
[0055] With respect to FIG. 11, the configuration of the
quad-mirror 68 includes the following. The rectangular aperture 74
has four corners 75a-75d. It is from these four corners that the
mirrors 70a, b, and 71a, b, extend. Thus, as previously indicated,
the corners of the mirrors do not all originate from the same apex.
Viewing mirror 71a, it is evident that it is defined by
substantially parallel side 72a, b, which originate respectfully
from corner 75a, 75b. Similarly, the substantially parallel sides
73a, 73b of the mirror 70b originate from corners 75b, 75c,
respectively. This same pattern occurs for the other mirrors 70a
and 71b. In such an arrangement, the cross-hair patterns are
created on the desired target. Also, as the sizes of the mirrors
can be made to have different areas, the intensity of the beam can
be made to vary.
[0056] Rectangular Spots
[0057] The spots (FIGS. 12a, 12b, 12c) produced by rectangular
mirrors are approximately rectangular. The direction of
interference spots and smears are similar to those described above
with respect to square mirrors. The spacing of the spots depends on
the width of the aperture in each direction, so the spacing of the
spots may not be the same for each direction.
[0058] X. Spring Compensation
[0059] The embodiment of FIG. 13 includes a pendulum 80 which hangs
down from a gimble mount 76. The gimble mount allows the pendulum
to swing in two directions of freedom. Hanging down from the gimble
mounts is the coil wire 78 which is used to power the laser
assembly 35. The laser assembly includes the driver board 41 to
which the wire is attached. Hanging down from the pendulum is the
damper 44. The damper 44 is damped by the damping arrangement 45 as
previously described.
[0060] The laser Diode Optical assembly in enclosure 40 requires
two electrical connections. This is typically achieved by the use
of very fine copper wires. But such wires present a surprisingly
significant spring torque on the pendulum. The nozero stiffness has
the property of dipping the beam if the housing is rotated forward.
This is one of the dominant limitating factors in miniaturizing a
pendulum assembly. Making the pendulum longer, the service loop
longer, and/or coiling the wires are techniques widely used in
existing system.
[0061] An embodiment of the invention has the wires formed into a
coil 78 and used as an extension spring. Stretched across the axis
of rotation of the pendulum 80 it functions as an "over center
mechanism". This has the inverse property that the beam pos up if
the housing is tilted forward.
[0062] By carefully matching the bending stiffness against the over
center spring the two effects are largely canceled. Although FIG.
13 shows a sectional view through one dimension, this effect works
simultaneously in all degrees of freedom of the pendulum.
[0063] A further benefit of this method is that the over center
spring acts to relieve gravitational drag torque on the bearings.
This may make it possible to use still shorter pendulums and
rollerless bearings.
[0064] XI. Field Calibration by Spring Compensation
[0065] A feature of the invention is field calibration. This is
typically accomplished by adjusting screws 78a, b, mounted in the
pendulum. In the field, should the laser beams come out of
alignment, the alignment can be corrected by adjusting the
distribution of weight on the pendulum. This is accomplished by
adjusting the position of the adjusting screws 78a, b, causing the
screws to move into or out of the pendulum.
[0066] Initial alignment during manufacturing can be accomplished
by removing weight from the damper 44 by for example a drilling
technique in order to align the laser beams with preestablished
targets.
[0067] With respect to another type of field alignment, the axial
positioning of the over center spring is important. If off-axis it
would leave a net torque on the pendulum. A novel feature of
invention allows for such a misalignment to be used to field
calibrate the pendulum. As shown in FIG. 14, screw pairs 82, 84 can
manipulate the spring mounting points 86, therein adjusting the
orientation of the suspended laser assembly. This has the desirable
property that the user need not come into contact with the delicate
pendulum assembly.
Industrial Applicability
[0068] The present invention provides for multiple embodiments
which can generate multiple laser beams for measuring, aligning,
leveling and other purposes. In addition, the embodiment are for
beam steering and focusing as well as mounting of the laser
itself.
* * * * *