Illumination – Light source and modifier – Including reflector
Reexamination Certificate
2001-09-28
2003-06-17
O'Shea, Sandra (Department: 2875)
Illumination
Light source and modifier
Including reflector
C362S800000, C362S300000, C362S310000, C257S098000, C313S512000
Reexamination Certificate
active
06578989
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to the field of optical devices and in particular, relates to an improved optical device including a transparent mold resin and a light reflecting member.
Light emitting apparatuses in which a light emitting element chip such as a light emitting diode is sealed by a mold resin are well known in the art. Light emitted from the light emitting element chip to its front is emitted as it is from the light emitting apparatus, but the light emitted in a diagonal direction from the light emitting element chip is totally reflected by a boundary surface of the mold resin or scattered by an inner wall of a housing, thus resulting in decreased light, thereby deteriorating the efficiency of light use.
Accordingly, as shown in
FIG. 26
, there has been heretofore proposed a light emitting apparatus having a good efficiency for outwardly emitting the light emitted from a light emitting element in a diagonal direction.
The conventional light emitting element of
FIG. 26
includes a light emitting element chip
101
, a transparence glass substrate
102
, lead frames
103
and
104
, a bonding wire
105
, a light reflecting member
106
, and a mold resin
108
made of an optically transparent resin. Lead frames
103
and
104
are disposed on a rear wall of the transparent glass substrate
102
, and the light emitting element chip
101
is mounted on a rear surface of the lead frame
103
to be connected with the lead frame
104
by the bonding wire
105
. A reflection surface
107
of the light reflecting member
106
is formed polyhedron by plural flat domains.
In this conventional light emitting apparatus, light is emitted backside from the light emitting element chip
101
to be reflected by the reflection surface
107
and emitted forward through the resin mold
108
and the transparent glass substrate
102
. In particular, light emitted from the light emitting element chip
101
in a diagonal direction is reflected back by the reflection surface
107
to be emitted forward through the resin mold
108
and the transparent glass substrate
102
, thereby improving the light use efficiency. When a light receiving element chip such as a photodiode is employed instead of the light emitting element chip
101
to receive incident light, a light receiving module having a good efficiency is provided.
The conventional light emitting apparatus, however, has the disadvantages that light reflected by the light reflecting member is obstructed by the light emitting element chip and the lead frame when it is emitted forward, thereby producing shadows of these components and deteriorating the advantage of utilization of light near the optical axis center where quantity of light should be provided most well.
Furthermore, because of darkness near the optical axis center in the directional pattern of light emitted by the light emitting apparatus, its appearance is bad as a light source for display, and malfunction of visual sense is produced.
In addition, when the light emitting apparatus is used at an intense place of temperature change, stresses are concentrated near a boundary surface of the light reflecting member and the mold resin because of a difference of coefficients of thermal expansion of the light reflecting member and the mold resin, thereby causing cracks in the mold resin.
SUMMARY OF INVENTION
It is, therefore, a primary object of this invention to provide an optical device having a predetermined directional pattern and a structure for preventing cracks, which is designed to be coupled with a light emitting element, such as a light emitting element chip or a light emitting element module sealing the light emitting element chip in a mold resin, or a light receiving element, such as a light receiving element chip or a light receiving element module sealing the light receiving element chip in a mold resin, by sealing or assembling the same.
It is a further object of this invention to provide an optical device including a mold resin and a light reflecting member sealed by the mold resin to be coupled with an optical element of a light emitting element or a light receiving element.
It is still further object of this invention to provide an optical apparatus including a plurality of optical devices each having a mold resin and a light reflecting member sealed by the mold resin to be coupled with an optical element of a light emitting element or a light receiving element.
According to another aspect of this invention, there is provided an optical device for an optical element to control a light path about emission light emitted from the optical element to external or incident light entered from external to the optical element, which includes a light reflecting member, a resin member covering at least a light reflection surface of the light reflecting member, and a bumper member interposed between the light reflecting member and the resin member, the resin member including a boundary surface for almost totally reflecting light deviated from a predetermined region in front of the optical element, the boundary surface of the resin member or the light reflecting member being so disposed that light deviating from the predetermined region in front of the optical element and passing between the optical element and an external of the optical device is reflected more than once with each of the boundary surface and the light reflecting member. The resin member may further include a lens portion for emitting or collecting light reaching the predetermined region in front of the optical element.
The bumper member may be disposed on a concentrated portion of stresses produced by the thermal expansion or shrinkage of the light reflecting member and the resin member.
Optical devices constructed in accordance with the present invention may have an improved efficiency of light use, and prevent production of any cracks by the bumper member for absorbing stresses produced by a difference of thermal expansion coefficients of the light reflecting member and the mold resin, thereby resolving the malfunctions that a crack is produced to hinder light emitted from the optical element or entered into the same, and the light reflecting member and the optical element are rusted or deteriorated by steam or gas to deteriorate the reliability.
The bumper member may have a soft layer having low degree hardness, a gas layer, a fluid layer or a cavity layer produced by shrinkage. The bumper member is desired to have a hardness of 50 or less prescribed with the Japanese Industrial Standard JISK6249.
Thus designed bumper member may ensure dissipation of a stress produced by a difference of thermal expansion coefficients of the light reflecting member and the mold resin.
Preferably, the bumper member may be configured to have a uniform or almost uniform thickness, namely, substantially uniform thickness. The thickness of the bumper member is desired to be 100 &mgr;m or less, more preferably not less than 30 &mgr;m or more than 100 &mgr;m.
Thus designed bumper member may minimize the deviation of an emission direction of light which is caused by a difference of refractive indexes of the mold resin and the bumper member, and optimize the center efficiency and the directive angle, thereby providing an optical device capable of affording variations in assembling.
A plurality of the above-mentioned optical devices may be arranged to provide an optical device array for optical elements for application to a light emission device of a thin and large scale type or a light receiving apparatus of a thin and large scale type which efficiently receives light entering into a front wall of the apparatus.
As the above-mentioned optical device array is coupled with optical elements, there may be provided an optical apparatus in which the optical elements are so disposed that light deviating from the predetermined region in front of each of the optical elements and passing between each of the optical element and an external of each of the optical device is reflected more than once with each of t
Kiyomoto Hironobu
Matsui Akira
Osumi Yoshimasa
Alavi Ali
O'Shea Sandra
Omron Corporation
Rosenthal & Osha L.L.P.
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