Optical: systems and elements – Lens – Single component with multiple elements
Reexamination Certificate
2002-12-30
2004-11-16
Epps, Georgia (Department: 2873)
Optical: systems and elements
Lens
Single component with multiple elements
C359S811000, C359S819000
Reexamination Certificate
active
06819508
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a lens assembly for an optical system and more particularly, to a lens assembly that connects a plastic lens to a plastic lens, a plastic lens to a glass lens, or a plastic lens to a barrel. A separation mold surface is set at different sides (outer sides, inner sides or an outer side and an inner side), and a spacer is located between the lenses.
BACKGROUND OF THE INVENTION
How to reduce factors of reducing the optical resolution and the precision of axial installation is the main issue of the present optical industry. In an optical system, a method of connecting two lenses together is shown in FIG.
1
.
A first lens
11
and a second lens
12
are connected with each other by the flat surfaces and their outer periphery are engaged with the barrel
13
. The axis of the first lens
11
and the axis of the second lens
12
can be located in alignment with each other when installing the lenses in the barrel by checking the degree of perpendicularity for the flat surfaces to the axes of the first and the second lenses
11
,
12
, the degree of alignment of the axis of the barrel
13
to the outer peripheries of the first and the second lenses
11
,
12
, the gap between the barrel
13
and the first and the second lenses
11
,
12
, and the relative degree of alignment of the contact positions of the barrel
13
and the two lenses
11
,
12
.
However, when the first and the second lenses
11
,
12
includes a plastic lens, there will be some problems when manufacturing. A typical plastic lens is shown in FIG.
2
and consist of four parts in a mold, cavity side sleeve
21
, cavity
22
, core side sleeve
23
and core
24
. Generally, the concentric contact plane is designated to the position
25
and the vertical contact plane is designated to the position
26
or position
27
. This arrangement usually leads to some problems.
First, the precise of the shape of the product depends upon the mold and the cavity
22
and the core
24
are machined by two-axle precise lathe which has a precision to 0.1 um and the inner periphery of the barrel is made by way of grinding which has a precision to 1 um. If the positions
25
,
26
,
27
of the lens are pushed by the molds and if the gate is allowed to be protruded, then the lens can be made by lathe which has a precision up to 2-5 um as shown in FIG.
3
. If the positions are pushed by ejection pins
28
and D-shaped cut
29
, then electric discharge machining is used which has a precision up to 20 um. Therefore, the optical axes is not easily to be put in alignment with each other.
SUMMARY OF THE INVENTION
The primary object of the present invention is to provide a lens assembly of an optical system and which can avoid the difference of optical axes between the outer periphery of lenses and barrel by way of connection between the lenses or between a spacer and a lens. This can increase resolution of the optical system.
The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention.
REFERENCES:
patent: 4488776 (1984-12-01), Skinner
patent: 4662717 (1987-05-01), Yamada et al.
patent: 4886342 (1989-12-01), Kudo et al.
patent: 5428480 (1995-06-01), Betensky
patent: 5570237 (1996-10-01), Sato
patent: 2002/0030899 (2002-03-01), Maeda et al.
patent: 2003/0081331 (2003-05-01), Abe
patent: 2003/0223130 (2003-12-01), Huang
Baxley Charles E.
Epps Georgia
Harrington Alicia M.
Largan Precision Co., Ltd.
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