U.S. patent application number 09/746589 was filed with the patent office on 2002-01-03 for image pickup lens unit.
This patent application is currently assigned to MILESTONE CO., LTD.. Invention is credited to Dou, Satoshi, Yoshida, Toshiyuki.
Application Number | 20020001144 09/746589 |
Document ID | / |
Family ID | 18691940 |
Filed Date | 2002-01-03 |
United States Patent
Application |
20020001144 |
Kind Code |
A1 |
Dou, Satoshi ; et
al. |
January 3, 2002 |
Image pickup lens unit
Abstract
An image pickup lens unit includes, as viewed from an object
side, a retainer having an aperture stop, an image pickup lens, and
a holder. The retainer having an aperture stop and the image pickup
lens are united with each other. The holder assumes a substantially
cylindrical shape and accommodates the image pickup lens such that
the image pickup lens is united with the holder in a manner movable
in relation to the holder, whereby movement of the retainer having
an aperture stop causes the image pickup lens to move in relation
to the holder to thereby carry out focus adjustment.
Inventors: |
Dou, Satoshi; (Tsurugashima,
JP) ; Yoshida, Toshiyuki; (Machida, JP) |
Correspondence
Address: |
Koda & Androlia
2029 Century Park East
Suite 3850
LOS ANGELES
CA
90067-3024
US
|
Assignee: |
MILESTONE CO., LTD.
|
Family ID: |
18691940 |
Appl. No.: |
09/746589 |
Filed: |
December 21, 2000 |
Current U.S.
Class: |
359/823 ;
348/E5.028; 359/811; 359/819 |
Current CPC
Class: |
G02B 7/023 20130101;
G02B 7/08 20130101; H04N 5/2254 20130101 |
Class at
Publication: |
359/823 ;
359/819; 359/811 |
International
Class: |
G02B 007/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 27, 2000 |
JP |
2000-192865 |
Claims
What is claimed is:
1. An image pickup lens unit comprising, as viewed from an object
side: a retainer having an aperture stop; an image pickup lens; and
a holder, wherein said retainer having an aperture stop and said
image pickup lens are united with each other; and said holder
assumes a substantially cylindrical shape and accommodates said
image pickup lens such that said image pickup lens is united with
said holder in a manner movable in relation to said holder, whereby
movement of said retainer having an aperture stop causes said image
pickup lens to move in relation to said holder so as to carry out
focus adjustment.
2. An image pickup lens unit comprising, as viewed from an object
side: a retainer having an aperture stop and assuming a circular
cross section; an image pickup lens assuming a circular cross
section; and a holder assuming a circular cross section, wherein
said retainer having an aperture stop and said image pickup lens
are united with each other; at least one protrusion is formed on a
circumferential portion of said image pickup lens; said holder
assumes a substantially cylindrical shape and has an elongated
groove formed on an inner cylindrical wall of said holder in such a
manner that the groove extends in the circumferential direction and
inclines in the axial direction; and said holder accommodates said
image pickup lens such that the protrusion is fitted into the
elongated groove to thereby unite said image pickup lens with said
holder in a manner movable along the elongated groove in relation
to said holder, whereby rotation of said retainer having an
aperture causes said image pickup lens to move along the elongated
groove in relation to said holder, thereby moving said image pickup
lens axially so as to carry out focus adjustment.
3. An image pickup lens unit according to claim 2, wherein two or
three said protrusions and two or three said elongated grooves are
provided.
4. An image pickup lens unit according to claim 2, wherein said
protrusion assumes the form of a hemisphere.
5. An image pickup lens unit comprising, as viewed from an object
side: an image pickup lens assuming a circular cross section; and a
holder assuming a circular cross section, wherein a surface of said
image pickup lens which faces an object, a surface of said image
pickup lens which faces an image plane, or both of the surfaces are
subjected to printing at a peripheral portion(s) of said image
pickup lens so as to form an aperture stop; at least one protrusion
is formed on a circumferential portion of said image pickup lens;
said holder assumes a substantially cylindrical shape and has an
elongated groove formed on an inner cylindrical wall of said holder
in such a manner that the groove extends in the circumferential
direction and inclines in the axial direction; and said holder
accommodates said image pickup lens such that the protrusion is
fitted into the elongated groove to thereby unite said image pickup
lens with said holder in a manner movable along the elongated
groove in relation to said holder, whereby rotation of said image
pickup lens causes said image pickup lens to move along the
elongated groove in relation to said holder, thereby moving said
image pickup lens axially so as to carry out focus adjustment.
6. An image pickup lens unit according to claim 5, wherein two or
three said protrusions and two or three said elongated grooves are
provided.
7. An image pickup lens unit according to claim 5, wherein said
protrusion assumes the form of a hemisphere.
8. An image pickup lens unit according to claim 5, further
comprising a knob attached to said image pickup lens and adapted to
carry out focus adjustment.
9. An image pickup lens unit comprising, as viewed from an object
side: a retainer having an aperture stop and assuming a circular
cross section; an image pickup lens assuming a circular cross
section; and a holder assuming a circular cross section, wherein
said retainer having an aperture stop and said image pickup lens
are united with each other; at least one protrusion is formed on a
circumferential portion of said retainer having an aperture stop;
said holder assumes a substantially cylindrical shape and has an
elongated groove formed on an inner cylindrical wall of said holder
in such a manner that the groove extends in the circumferential
direction and inclines in the axial direction; and said holder
accommodates said image pickup lens such that the protrusion is
fitted into the elongated groove to thereby unite said retainer
having an aperture stop with said holder in a manner movable along
the elongated groove in relation to said holder, whereby rotation
of said retainer having an aperture causes said image pickup lens
to move along the elongated groove in relation to said holder,
thereby moving said image pickup lens axially so as to carry out
focus adjustment.
10. An image pickup lens unit according to claim 9, wherein two or
three said protrusions and two or three said elongated grooves are
provided.
11. An image pickup lens unit according to claim 9, wherein said
protrusion assumes the form of a hemisphere.
12. An image pickup lens unit according to claim 9, further
comprising a knob attached to said retainer having an aperture stop
and adapted to carry out focus adjustment.
13. An image pickup lens unit comprising, as viewed from an object
side: a retainer having an aperture stop and assuming a circular
cross section; an image pickup lens assuming a circular cross
section; and a holder assuming a circular cross section, wherein
said retainer having an aperture stop and said image pickup lens
are united with each other; at least two toothlets are formed on a
peripheral portion of a surface of said image pickup lens which
faces an image plane, such that upper faces of said toothlets have
sloped surfaces formed along a circumference of said image pickup
lens; said holder assumes a substantially cylindrical shape and has
at least two protrusions formed on an inner cylindrical wall of
said holder so as to hold said image pickup lens through contact
between the protrusions and the upper faces of the toothlets; and
said holder accommodates said image pickup lens such that said
image pickup lens can move in relation to said holder while contact
between the protrusions and the sloped surfaces of the upper faces
of the toothlets is maintained, whereby rotation of said retainer
having an aperture causes said image pickup lens to move while
maintaining contact of the sloped surfaces with the protrusions,
thereby moving said image pickup lens axially so as to carry out
focus adjustment.
14. An image pickup lens unit according to claim 13, wherein the
upper faces of the toothlets have horizontal surfaces formed in
such a manner as to be continuous with highest ends of the sloped
surfaces.
15. An image pickup lens unit according to claim 13, wherein the
sloped surfaces are planes.
16. An image pickup lens unit according to claim 13, wherein two to
four said toothlets and two to four said protrusions are
provided.
17. An image pickup lens unit according to claim 16, wherein the
toothlets assume the same height; the protrusions assume the same
height; and the toothlet is formed such that a side view of the
toothlet assumes a form of a substantial sawtooth.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an image pickup lens unit.
More particularly, the invention relates to an image pickup lens
unit for use with a small-sized CCD or CMOS, which serves as an
image pickup element, and which enables an image pickup lens to be
united with a holder without being incorporated into a barrel.
[0003] 2. Description of the Related Art
[0004] Conventionally, as shown in FIG. 6, an image pickup lens
unit for use with a CCD or CMOS is composed of at least five
components; namely, a lens barrel, a lens retainer, an image pickup
lens, a stop, and a holder. However, it has been possible to freely
perform focus adjustment of the image pickup lens after assembly
thereof.
[0005] In recent years, there has been a demand for very
significant reductions in both the size and cost of electronic
camera equipment. In this environment, the image pickup lens unit
for cameras are required to reduce the number of components, size,
and cost. Particularly, there has been a movement to unify the
holder and the lens in the monitor lens unit used in mobile
equipment or cellular phones in order to accommodate the trend
towards reductions in the size and cost of such equipment.
[0006] In order to meet the above requirement, an united-type image
pickup lens unit has been devised in which a lens is fitted into a
holder, for use in electronic camera equipment employing a solid
image pickup element. The image pickup lens unit is composed of
three components; namely, a retainer having an aperture stop, an
image pickup lens, and a holder. Alternatively, the lens surface is
subjected to printing so as to form an aperture stop, instead of
using a retainer having an aperture stop. Therefore, the image
pickup lens unit is composed of two components; namely, an image
pickup lens and a holder, thereby realizing low cost through
simplified assembly and a reduction in the number of components.
Since the number of components is small, such an image pickup lens
unit can be easily assembled and is therefore suitable for mass
production.
[0007] However, since the above image pickup lens unit employing a
united lens-and-holder structure does not have a focusing mechanism
after assembly, maintaining high standards of manufacturing
accuracy of respective components and the attachment accuracy of a
CCD or CMOS are very important in terms of image quality.
Specifically, the shorter the focal distance of the image pickup
lens unit, the more important the distance of the image pickup lens
and an image plane, as of a CCD or CMOS, becomes in terms of image
quality. Since an image pickup lens for use with the
above-mentioned image pickup element employs high brightness;
specifically Fno=2.0-2.8, the focal depth becomes shallow. As a
result, even a minor error in lens position causes defocus. In
other words, since manufacturing errors of the respective
components cause a variation in the design distance to an object,
defocus will occur even when the distance to an object is set to
the design distance in the course of mass production, resulting in
poor image quality or an unfocused image.
[0008] Furthermore, an machining error of an image pickup lens, a
contraction error of an image pickup lens in the course of molding,
or a holder dimensional error, for example, will cause a defect in
the final image. Accordingly, even when the united lens-and-holder
structure is employed in an attempt to reduce cost and weight and
in an attempt to facilitate mass production, defects will
frequently result unless a focusing mechanism is employed, so that
the costs increase undesirably, and mass production becomes
difficult.
SUMMARY OF THE INVENTION
[0009] In view of growing demands for inexpensive high-performance
lenses so as to be compatible with electronic image pickup
equipment which is undergoing reduction in size and weight, an
object of the present invention is to provide a small-sized,
inexpensive, high-performance image pickup lens unit.
[0010] More particularly, an object of the present invention is to
provide a high-performance image pickup lens unit for use with
electronic image pickup equipment, enabling an image pickup lens
and a holder to be united with each other through, for example,
fitting, so as to avoid use of a barrel--which is conventionally
used to hold and adjust the lens--for reduction in weight and
costs, and enabling focusing after assembly.
[0011] Herein, an assembly obtained through incorporation of an
image pickup lens into a peripheral component (a holder, for
example) is called an "image pickup lens unit."
[0012] A first aspect of the present invention provides an image
pickup lens unit comprising, as viewed from an object side, a
retainer having an aperture stop, an image pickup lens, and a
holder. The retainer and the image pickup lens are united with each
other. The holder assumes a substantially cylindrical shape and
accommodates the image pickup lens such that the image pickup lens
is united with the holder in a manner movable in relation to the
holder, whereby movement of the retainer causes the image pickup
lens to move in relation to the holder to thereby carry out focus
adjustment.
[0013] According to the first aspect, movement of the retainer
having an aperture stop causes the image pickup lens to move, since
the image pickup lens is united with the retainer. The image pickup
lens moves while being accommodated within the holder, thereby
maintaining a state in which the image pickup lens is united with
the holder. Through movement of the image pickup lens, the image
pickup lens is focused.
[0014] A second aspect of the present invention provides an image
pickup lens unit comprising, as viewed from an object side, a
retainer having an aperture stop and assuming a circular cross
section, an image pickup lens assuming a circular cross section,
and a holder assuming a circular cross section. The retainer and
the image pickup lens are united with each other. At least one
protrusion is formed on a circumferential portion of the image
pickup lens. The holder assumes a substantially cylindrical shape
and has an elongated groove formed on an inner cylindrical wall
thereof in such a manner that the groove extends in the
circumferential direction and inclines in the axial direction. The
holder accommodates the image pickup lens such that the protrusion
is fitted into the elongated groove to thereby unite the image
pickup lens with the holder in a manner movable along the elongated
groove in relation to the holder, whereby rotation of the retainer
causes the image pickup lens to move along the elongated groove in
relation to the holder, thereby moving the image pickup lens
axially so as to carry out focus adjustment.
[0015] According to the second aspect, when the retainer having an
aperture stop is rotated, the image pickup lens rotates and moves,
since the image pickup lens is united with the retainer. The
protrusion formed on the circumferential portion of the image
pickup lens is fitted into the elongated groove, which is formed on
the inner cylindrical wall of the holder. Accordingly, as the image
pickup lens rotates, the protrusion moves along the elongated
groove, which inclines in the axial direction of the holder; as a
result, the image pickup lens moves axially. The image pickup lens
moves rotatively while being accommodated within the holder,
thereby maintaining a state in which the image pickup lens is
united with the holder. Through axial movement of the image pickup
lens, the image pickup lens is focused.
[0016] A third aspect of the present invention provides an image
pickup lens unit comprising, as viewed from an object side, an
image pickup lens assuming a circular cross section; and a holder
assuming a circular cross section. The surface of the image pickup
lens which faces an object, the surface of the image pickup lens
which faces an image plane, or both of the surfaces are subjected
to printing at a peripheral portion(s) thereof so as to form an
aperture stop. At least one protrusion is formed on a
circumferential portion of the image pickup lens. The holder
assumes a substantially cylindrical shape and has an elongated
groove formed on an inner cylindrical wall thereof in such a manner
that the groove extends in the circumferential direction and
inclines in the axial direction. The holder accommodates the image
pickup lens such that the protrusion is fitted into the elongated
groove to thereby unite the image pickup lens with the holder in a
manner movable along the elongated groove in relation to the
holder, whereby rotation of the image pickup lens causes the image
pickup lens to move along the elongated groove in relation to the
holder, thereby moving the image pickup lens axially so as to carry
out focus adjustment.
[0017] According to the third aspect, the protrusion formed on the
circumferential portion of the image pickup lens is fitted into the
elongated groove, which is formed on the inner cylindrical wall of
the holder. Accordingly, as the image pickup lens rotates, the
protrusion moves along the elongated groove, which inclines in the
axial direction of the holder; as a result, the image pickup lens
moves axially. The image pickup lens moves rotatively while being
accommodated within the holder, thereby maintaining a state in
which the image pickup lens is united with the holder. Through
axial movement of the image pickup lens, the image pickup lens is
focused.
[0018] A fourth aspect of the present invention provides an image
pickup lens unit comprising, as viewed from an object side, a
retainer having an aperture stop and assuming a circular cross
section, an image pickup lens assuming a circular cross section,
and a holder assuming a circular cross section. The retainer and
the image pickup lens are united with each other. At least one
protrusion is formed on a circumferential portion of the retainer.
The holder assumes a substantially cylindrical shape and has an
elongated groove formed on an inner cylindrical wall thereof in
such a manner that the groove extends in the circumferential
direction and inclines in the axial direction. The holder
accommodates the image pickup lens such that the protrusion is
fitted into the elongated groove to thereby unite the retainer with
the holder in a manner movable along the elongated groove in
relation to the holder, whereby rotation of the retainer causes the
image pickup lens to move along the elongated groove in relation to
the holder, thereby moving the image pickup lens axially so as to
carry out focus adjustment.
[0019] According to the fourth aspect, when the retainer having an
aperture stop is rotated, the image pickup lens rotates and moves,
since the image pickup lens is united with the retainer. The
protrusion formed on the circumferential portion of the retainer is
fitted into the elongated groove, which is formed on the inner
cylindrical wall of the holder. Accordingly, as the retainer
rotates, the protrusion moves along the elongated groove, which
inclines in the axial direction of the holder; as a result, the
retainer moves axially, and thus the image pickup lens moves
axially. The image pickup lens moves rotatively while being
accommodated within the holder, thereby maintaining a state in
which the image pickup lens is united with the holder. Through
axial movement of the image pickup lens, the image pickup lens is
focused.
[0020] A fifth aspect of the present invention provides an image
pickup lens unit comprising, as viewed from an object side, a
retainer having an aperture stop and assuming a circular cross
section, an image pickup lens assuming a circular cross section,
and a holder assuming a circular cross section. The retainer and
the image pickup lens are united with each other. At least two
toothlets are formed on a peripheral portion of a surface of the
image pickup lens which faces an image plane, such that upper faces
thereof have sloped surfaces formed along the circumference of the
image pickup lens. The holder assumes a substantially cylindrical
shape and has at least two protrusions formed on an inner
cylindrical wall thereof so as to hold the image pickup lens
through contact between the protrusions and the upper faces of the
toothlets. The holder accommodates the image pickup lens such that
the image pickup lens can move in relation to the holder while
contact between the protrusions and the sloped surfaces of the
upper faces of the toothlets is maintained, whereby rotation of the
retainer causes the image pickup lens to move while maintaining
contact of the sloped surfaces with the protrusions, thereby moving
the image pickup lens axially so as to carry out focus
adjustment.
[0021] According to the fifth aspect, when the retainer having an
aperture stop is rotated, the image pickup lens rotates and moves,
since the image pickup lens is united with the retainer. The image
pickup lens is held within the holder such that the upper faces of
the toothlets, which are formed on a peripheral portion of the
surface of the image pickup lens which faces an image plane, are in
contact with the protrusions formed on the inner cylindrical wall
of the holder. Rotation of the retainer causes the image pickup
lens to move rotatively while contact between the protrusions and
the sloped surfaces of the upper faces is maintained. Since the
upper faces of the toothlets have sloped surfaces sloping along the
circumference direction, the image pickup lens rotates while
maintaining contact between the protrusions and the upper faces of
the toothlets. Therefore, the image pickup lens rotates in
accordance with the shape of the sloped surfaces of the upper faces
of the toothlets; as a result, the image pickup lens moves axially.
The image pickup lens moves rotatively while being accommodated
within the holder, thereby maintaining a state in which the image
pickup lens is united with the holder. Through axial movement of
the image pickup lens, the image pickup lens can be focused.
[0022] According to the first aspect, in spite of employment of the
unitary lens-and-holder structure, the image pickup lens can be
focused through movement thereof. Thus, even when errors in
manufacture of components or errors in attachment of a CCD or CMOS
are of a large magnitude, the image pickup lens can be focused
accordingly after assembly. Therefore, a small-sized,
high-performance image pickup lens unit can be obtained.
Furthermore, simplified assembly and a reduction in the number of
components bring about a reduction in weight and cost and enhance
suitability to mass production. Also, accuracy required of
components is not very high, thereby reducing the cost of the
components. By virtue of a synergetic effect of these affirmative
factors, costs are reduced further. Additionally, macrophotographic
adjustment is possible, thereby enhancing convenience.
[0023] According to the second aspect, in spite of employment of
the unitary lens-and-holder structure, the image pickup lens can be
readily focused after assembly through rotation of the retainer
having an aperture stop. Thus, a high-performance image pickup lens
unit can be obtained. Simplified assembly and a reduction in the
number of components bring about a reduction in weight and cost and
enhance suitability to mass production. Also, accuracy required of
components is not very high, thereby reducing the cost of the
components. By virtue of a synergetic effect of these affirmative
factors, costs are reduced further.
[0024] According to the third aspect, in spite of employment of the
unitary lens-and-holder structure, the image pickup lens can be
readily focused after assembly through rotation thereof. Thus, a
high-performance image pickup lens unit can be obtained. Since the
retainer having an aperture stop is not employed, the number of
components is reduced accordingly. Simplified assembly and a
reduction in the number of components bring about a reduction in
weight and cost and enhance suitability to mass production. Also,
accuracy required of components is not very high, thereby reducing
the cost of the components. By virtue of a synergetic effect of
these affirmative factors, costs are reduced further.
[0025] According to the fourth aspect, in spite of employment of
the unitary lens-and-holder structure, the image pickup lens can be
readily focused after assembly through rotation of the retainer
having an aperture stop. Thus, a high-performance image pickup lens
unit can be obtained. Simplified assembly and a reduction in the
number of components bring about a reduction in weight and cost and
enhance suitability to mass production. Also, accuracy required of
components is not very high, thereby reducing the cost of the
components. By virtue of a synergetic effect of these affirmative
factors, costs are reduced further. Additionally, the manufacture
of the image pickup lens does not involve formation of the
protrusion, thereby providing another affirmative factor for
further reduction in cost.
[0026] According to the fifth aspect, in spite of employment of the
unitary lens-and-holder structure, the image pickup lens can be
readily focused after assembly through rotation of the retainer
having an aperture stop. Thus, a high-performance image pickup lens
unit can be obtained. Simplified assembly and a reduction in the
number of components bring about a reduction in weight and cost and
enhance suitability to mass production. Also, accuracy required of
components is not very high, thereby reducing the cost of the
components. By virtue of a synergetic effect of these affirmative
factors, costs are reduced further.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a collective view showing an image pickup lens
unit according to a first embodiment of the present invention and
components of the image pickup lens by means of the corresponding
plan views, longitudinal sectional views, and bottom views;
[0028] FIG. 2 is a collective view showing an image pickup lens
unit according to a second embodiment of the present invention and
components of the image pickup lens by means of the corresponding
plan views, longitudinal sectional views, and bottom views;
[0029] FIG. 3 is a collective view showing an image pickup lens
unit according to a third embodiment of the present invention and
components of the image pickup lens by means of the corresponding
plan views, longitudinal sectional views, and bottom views;
[0030] FIG. 4 is a collective view showing an image pickup lens
unit according to a fourth embodiment of the present invention and
components of the image pickup lens by means of the corresponding
plan views, longitudinal sectional views, and bottom views;
[0031] FIG. 5A is an enlarged side view of a second image pickup
lens;
[0032] FIG. 5B is a perspective view of the second image pickup
lens as viewed from the image plane side; and
[0033] FIG. 6 is a longitudinal, partially sectional view showing a
conventional image pickup lens unit for use with a CCD or CMOS.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0034] Embodiments of the present invention will next be described
in detail with reference to the drawings.
[0035] Among four embodiments of the present invention, a first
embodiment of the present invention will be described first. FIG. 1
shows an image pickup lens unit 2 according to the first
embodiment. The image pickup lens unit 2 includes a first retainer
4 having an aperture stop, a first image pickup lens 6, and a
holder 8.
[0036] The first retainer 4 assumes a circular cross section. A
stop is formed at a central portion of the first retainer 4 such
that the diameter reduces stepwise in the axial direction from the
object side toward the image plane side. An object-side end portion
of the first retainer 4 assumes the form of a flange. Two thin
columnar leg portions 10 project from the image plane side of the
first retainer 4 at symmetrically opposite positions.
[0037] The first image pickup lens 6 assumes a circular cross
section. Three first ribs 16, each assuming the form of a
hemisphere, project from the circumference of the first image
pickup lens 6 in such a manner as to be arranged 120 degrees apart
from one another. Two hole portions 12 are formed on the object
side of the first image pickup lens 6 at symmetrically opposite
positions. The leg portions 10 are press fitted into the
corresponding hole portions 12 to thereby unite the first retainer
4 and the first image pickup lens 6. Alternatively, in place of
press-fit engagement, the leg portions 10 may be loosely fitted
into the corresponding hole portions 12, followed by bonding. In
this case, the diameter of the leg portions 10 is reduced to allow
a loose fit. Through unified engagement of the first retainer 4 and
the first image pickup lens 6, rotation of the first retainer 4
causes the first image pickup lens 6 to rotate together.
[0038] The holder 8 assumes a substantially cylindrical shape such
that the image-plane-side end portion thereof assumes an outside
and an inside diameter greater than those of the remaining portion
thereof. A rest portion 14 is formed annularly on the inner
cylindrical wall of the holder 8 near the object-side end of the
holder 8. The rest portion 14 serves as a stopper for the first
image pickup lens 6. Three adjustment grooves 18 are formed at
equal spacings on a portion of the cylindrical wall of the holder 8
located between the object-side end and the rest portion 14. Each
of the adjustment grooves 18 assumes the form of a gentle,
stepwise, spiral. The longitudinal sectional view of FIG. 1 shows
the adjustment groove 18 located on the far side of the sectional
plane. The holder 8 accommodates the first image pickup lens 6 in a
portion thereof extending between the object-side end and the rest
portion 14. The image-plane-side surface of the first image pickup
lens 6 comes into contact with the rest portion 14 upon maximum
retraction of the image pickup lens 6. The first image pickup lens
6 is accommodated in the holder 8 such that the three first ribs 16
of the first image pickup lens 6 are fitted into the corresponding
adjustment grooves 18. As the first image pickup lens 6 is rotated,
the first ribs 16 move along the corresponding adjustment grooves
18. Since the adjustment grooves 18 each assume the form of a
gentle, stepwise, spiral, movement of the first ribs 16 along the
corresponding adjustment grooves 18 causes the first image pickup
lens 6 to move in the axial direction of the holder 8 (in the axial
direction of the first image pickup lens 6), whereby the first
image pickup lens 6 can be focused.
[0039] In a mass production line, after the first retainer 4, the
first image pickup lens 6, and the holder 8 are assembled into the
above-described structure, the first retainer 4 is rotated slightly
so as to focus the first image pickup lens 6 in an
inspection-adjustment step, which is performed through observation
of a monitored image. If needed, after the first image pickup lens
6 is focused, the first image pickup lens 6 and the holder 8 are
bonded together. When a macrophotographic function is to be
imparted to the image pickup lens unit 2, the first image pickup
lens 6 and the holder 8 are not bonded, so that macrophotography is
possible through rotation of the first retainer 4.
[0040] A second embodiment of the present invention will next be
described. FIG. 2 shows an image pickup lens unit 52 according to
the second embodiment. The image pickup lens unit 52 includes a
first image pickup lens 6 and a holder 8. In place of a retainer
having an aperture stop, the image pickup lens unit 52 employs a
focusing/macrophotographic adjustment knob 20. Also, the
object-side surface of the first image pickup lens 6 is subjected
to printing at a peripheral portion thereof so as to form an
aperture stop.
[0041] The focusing/macrophotographic adjustment knob 20 assumes
the form of an crescent and includes a handle 22 projecting from
the center of the crescent form. Leg portions 24 project from the
corresponding end portions of the crescent form toward the image
plane.
[0042] The first image pickup lens 6 assumes a circular cross
section. Three first ribs 16, each assuming the form of a
hemisphere, project from the circumference of the first image
pickup lens 6 in such a manner as to be arranged 120 degrees apart
from one another. The object-side surface of the first image pickup
lens 6 is subjected to printing in black at a peripheral portion
thereof so as to form an aperture stop. Only light impinging on an
effective surface corresponding to the aperture stop is allowed to
pass through the first image pickup lens 6. Two hole portions 12
are formed on the object side of the first image pickup lens 6 at
symmetrically opposite positions. The leg portions 24 are press
fitted into the hole portions 12 to thereby unite the
focusing/macrophotographic adjustment knob 20 and the first image
pickup lens 6. Alternatively, in place of press-fit engagement, the
leg portions 24 may be loosely fitted into the hole portions 12,
followed by bonding. In this case, the diameter of the leg portions
24 is reduced to allow a loose fit. Through unified engagement of
the focusing/macrophotographic adjustment knob 20 and the first
image pickup lens 6, rotation of the focusing/macrophotographic
adjustment knob 20 causes the first image pickup lens 6 to rotate
together.
[0043] Since the holder 8 assumes the same structure as that of the
holder 8 of the first embodiment, further description of the
structure of the holder 8 is omitted here. As in the case of the
first embodiment, the holder 8 accommodates the first image pickup
lens 6 in a portion thereof extending between the object-side end
and the rest portion 14. The image-plane-side surface of the first
image pickup lens 6 comes into contact with the rest portion 14
upon maximum retraction of the image pickup lens 6. The first image
pickup lens 6 is accommodated in the holder 8 such that the three
first ribs 16 of the first image pickup lens 6 are fitted into the
corresponding adjustment grooves 18. As the first image pickup lens
6 is rotated, the first ribs 16 move along the corresponding
adjustment grooves 18. Since the adjustment grooves 18 each assume
the form of a gentle, stepwise, spiral, movement of the first ribs
16 along the corresponding adjustment grooves 18 causes the first
image pickup lens 6 to move in the axial direction of the holder 8
(in the axial direction of the first image pickup lens 6), whereby
the first image pickup lens 6 can be focused.
[0044] In a mass production line, after the
focusing/macrophotographic adjustment knob 20, the first image
pickup lens 6, and the holder 8 are assembled into the
above-described structure, the focusing/macrophotograp- hic
adjustment knob 20 is rotated slightly so as to focus the first
image pickup lens 6 in an inspection-adjustment step, which is
performed through observation of a monitored image. If needed,
after the first image pickup lens 6 is focused, the first image
pickup lens 6 and the holder 8 are rigidly bonded. When a
macrophotographic function is to be imparted to the image pickup
lens unit 52, the first image pickup lens 6 and the holder 8 are
not bonded, so that macrophotography is possible through rotation
of the focusing/macrophotographic adjustment knob 20. When the
image pickup lens unit 52 is to be used as a fixed-focus lens unit,
the focusing/macrophotographic adjustment knob 20 is removed, and
the first image pickup lens 6 and the holder 8 are rigidly
bonded.
[0045] Next, a third embodiment of the present invention will be
described. FIG. 3 shows an image pickup lens unit 54 according to
the third embodiment. The image pickup lens unit 54 includes a
focusing/macrophotographic adjustment knob 20, a second retainer 28
having an aperture stop, a first image pickup lens 6, and a holder
8.
[0046] The focusing/macrophotographic adjustment knob 20 assumes
the form of a crescent and includes a handle 22 projecting from the
center of the crescent form. Leg portions 24 project from the
corresponding end portions of the crescent form toward the image
plane.
[0047] The second retainer 28 assumes a circular cross section. A
stop is formed at a central portion of the second retainer 28 such
that diameter reduces stepwise in the axial direction from the
object side toward the image plane side. Two thin columnar
protrusions 31 project from the image plane side of the second
retainer 28 at symmetrically opposite positions. Two second ribs
30, each assuming the form of a hemisphere, project from the
circumference of the second retainer 28 in such a manner as to be
arranged 180 degrees apart from each other. Two recesses 29 are
formed on the object side of the second retainer 28 at
symmetrically opposite positions. The leg portions 24 are press
fitted into the corresponding recesses 29 to thereby unite the
focusing/macrophotographic adjustment knob 20 and the second
retainer 28. Alternatively, in place of press-fit engagement, the
leg portions 24 may be loosely fitted into the corresponding
recesses 29, followed by bonding. In this case, the diameter of the
leg portions 24 is reduced to allow a loose fit. Through unified
engagement of the focusing/macrophotographic adjustment knob 20 and
the second retainer 28, rotation of the focusing/macrophotographic
adjustment knob 20 causes the second retainer 28 to rotate
together.
[0048] The first image pickup lens 6 assumes a circular cross
section. Two hole portions 12 are formed on the object side of the
first image pickup lens 6 at symmetrically opposite positions. The
protrusions 31 are press fitted into the corresponding hole
portions 12 to thereby unite the second retainer 28 and the first
image pickup lens 6. Alternatively, in place of press-fit
engagement, the protrusions 31 may be loosely fitted into the
corresponding hole portions 12, followed by bonding. In this case,
the diameter of the protrusions 31 is reduced to allow a loose fit.
Through unified engagement of the second retainer 28 and the first
image pickup lens 6, rotation of the second retainer 28 causes the
first image pickup lens 6 to rotate together.
[0049] The holder 8 assumes a substantially cylindrical shape such
that the image-plane-side end portion thereof assumes an outside
and an inside diameter greater than those of the remaining portion
thereof. A rest portion 14 is formed annularly on the inner
cylindrical wall of the holder 8 near the object-side end of the
holder 8. The rest portion 14 serves as a stopper for the first
image pickup lens 6. Two adjustment grooves 18 are formed at
opposite positions on a portion of the cylindrical wall of the
holder 8 located between the object-side end and the rest portion
14. As in the case of the first embodiment, each of the adjustment
grooves 18 assumes the form of a gentle, stepwise, spiral. The
holder 8 accommodates the first image pickup lens 6 in a portion
thereof extending between the object-side end and the rest portion
14. The image-plane-side surface of the first image pickup lens 6
comes into contact with the rest portion 14 upon maximum retraction
of the image pickup lens 6. The first image pickup lens 6 is
accommodated in the holder 8 such that the two second ribs 30 of
the second retainer 28 are fitted into the corresponding adjustment
grooves 18. As the second retainer 28 is rotated, the second ribs
30 move along the corresponding adjustment grooves 18. Since the
adjustment grooves 18 each assume the form of a gentle, stepwise,
spiral, movement of the second ribs 30 along the corresponding
adjustment grooves 18 causes the first image pickup lens 6 to move
in the axial direction of the holder 8 (in the axial direction of
the first image pickup lens 6), whereby the first image pickup lens
6 can be focused.
[0050] In a mass production line, after the second retainer 28, the
first image pickup lens 6, and the holder 8 are assembled into the
above-described structure, the focusing/macrophotographic
adjustment knob 20 is rotated slightly so as to focus the first
image pickup lens 6 in an inspection-adjustment step, which is
performed through observation of a monitored image. If needed,
after the first image pickup lens 6 is focused, the second retainer
28 and the holder 8 are rigidly bonded. When a macrophotographic
function is to be imparted to the image pickup lens unit 54, the
second retainer 28 and the holder 8 are not bonded, so that
macrophotography is possible through rotation of the
focusing/macrophotographic adjustment knob 20. When the image
pickup lens unit 54 is to be used as a fixed-focus lens unit, the
focusing/macrophotographic adjustment knob 20 is removed, and the
second retainer 28 and the holder 8 are rigidly bonded.
[0051] A fourth embodiment of the present invention will next be
described. FIG. 4 shows an image pickup lens unit 56 according to
the fourth embodiment. The image pickup lens unit 56 includes a
third retainer 42 having an aperture stop, a second image pickup
lens 32, and a holder 8.
[0052] The third retainer 42 assumes a circular cross section. A
stop is formed at a central portion of the third retainer 42 such
that the diameter reduces stepwise in the axial direction from the
object side toward the image plane side. An object-side end portion
of the third retainer 42 assumes the form of a flange, so that the
remaining portion has an outside diameter substantially equal to
the inside diameter of the holder 8, which will be described later.
Two thin columnar leg portions 10 project from the image plane side
of the third retainer 42 at symmetrically opposite positions.
[0053] The second image pickup lens 32 assumes a circular cross
section. Two hole portions 12 are formed on the object side of the
second image pickup lens 32 at symmetrically opposite positions.
The leg portions 10 are press fitted into the corresponding hole
portions 12 to thereby unite the third retainer 42 and the second
image pickup lens 32. Alternatively, in place of press-fit
engagement, the leg portions 10 may be loosely fitted into the
corresponding hole portions 12, followed by bonding. In this case,
the diameter of the leg portions 10 is reduced to allow a loose
fit. Through unified engagement of the third retainer 42 and the
second image pickup lens 32, rotation of the third retainer 42
causes the second image pickup lens 32 to rotate together.
[0054] FIG. 5A is an enlarged side view of the second image pickup
lens 32, and FIG. 5B is a perspective view of the second image
pickup lens 32 as viewed from the image plane side. Four toothlets
34 are formed annularly every 90 degrees on a peripheral portion of
the image-plane-side surface of the image pickup lens 32. The
toothlet 34 assumes the form of a substantial sawtooth. The upper
face of the toothlet 34 includes a minor horizontal-surface portion
44 and a sloped portion 36, which slopes linearly and is curved
along the circumference of the second image pickup lens 32. An
upright portion 38 is formed between the horizontal-surface portion
44 and the sloped portion 36 of the adjacent toothlet 34.
[0055] The holder 8 assumes a substantially cylindrical shape such
that the image-plane-side end portion thereof assumes an outside
and an inside diameter greater than those of the remaining portion
thereof. A rest portion 14 is formed annularly on the inner
cylindrical wall of the holder 8 near the object-side end of the
holder 8. Four lens holder ribs 40 are formed at 90-degree
intervals on the object side of the rest portion 14 at the boundary
between the rest portion 14 and the inner cylindrical wall of the
holder 8. The lens retainer rib 40 is a protrusion assuming the
form of a small rectangular parallelepiped. The holder 8
accommodates the second image pickup lens 32 in a portion thereof
extending between the object-side end and the rest portion 14. The
upper faces of the corresponding toothlets 34 of the second image
pickup lens 32 are in contact with the lens holder ribs 40, whereby
the second image pickup lens 32 are held on the lens holder ribs
40. When the second image pickup lens 32 is rotated, the sloped
portions of the corresponding upper faces of the toothlets 34 slide
on the corresponding lens holder ribs 40. Since the sloped portions
36 are sloped linearly, sliding of the sloped portions 36 on the
corresponding lens holder ribs 40 causes the second image pickup
lens 32 to move in the axial direction of the holder 8 (in the
axial direction of the second image pickup lens 32), whereby the
second image pickup lens 32 can be focused. The present embodiment
employs four toothlets 34 and four lens holder ribs 40. The number
of the toothlets 34 and the lens holder ribs 40 are not
particularly limited, but is preferably two or more. If too many of
the toothlets 34 and the lens holder ribs 40 are employed, the
rotatable distance becomes too short.
[0056] In a mass production line, after the third retainer 42, the
second image pickup lens 32, and the holder 8 are assembled into
the above-described structure, the third retainer 42 is rotated
slightly so as to focus the second image pickup lens 32 in an
inspection-adjustment step, which is performed through observation
of a monitored image. If needed, after the second image pickup lens
32 is focused, the third retainer 42 and the holder 8 are rigidly
bonded. When a macrophotographic function is to be imparted to the
image pickup lens unit 56, the third retainer 42 and the holder 8
are not bonded, so that macrophotography is possible through
rotation of the third retainer 42. When the image pickup lens unit
56 is to be used as a fixed-focus lens unit, the third retainer 42
and the holder 8 are rigidly bonded.
[0057] According to the above-described first through fourth
embodiments, although the image pickup lens unit has a unified
lens-and-holder structure, the image pickup lens can be readily
focused after assembly through rotation of a retainer having an
aperture stop or through rotation of the image pickup lens. Thus,
even when errors in manufacture of components or errors in
attachment of a CCD or CMOS are of a large magnitude, the image
pickup lens can still be focused accordingly. Therefore, a
high-quality image pickup lens unit can be provided. Also, since
there is no need to pursue extremely high accuracy with respect to
components, the cost of components can be held down to a low
level.
* * * * *