Active solid-state devices (e.g. – transistors – solid-state diode – Non-single crystal – or recrystallized – semiconductor... – Amorphous semiconductor material
Reexamination Certificate
2000-04-07
2003-06-24
Flynn, Nathan J. (Department: 2826)
Active solid-state devices (e.g., transistors, solid-state diode
Non-single crystal, or recrystallized, semiconductor...
Amorphous semiconductor material
C257S291000, C257S292000, C257S294000, C257S432000, C257S436000, C359S619000, C359S620000, C359S621000, C359S622000
Reexamination Certificate
active
06583438
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a solid-state imaging device having a microlens and sealing resin on the microlens.
2. Description of the Prior Art
As for a solid-state imaging device using a CCD (Charge Coupled Device), the area of a photodiode serving as a light-receiving portion has been decreased because of requests for decrease in size and improvement in resolution. To compensate the deterioration of a condensing efficiency due to decrease of the area of the light-receiving portion, the so-called microlens has been developed and used.
The microlens is normally made of resin and set above a light-receiving portion formed for each pixel to directly refract light not incoming to the light-receiving portion, to condense the light in the light-receiving portion, and to improve the condensing efficiency and the sensitivity.
However, because the microlens is weak in humidity, it is necessary to protect the microlens by any means when the lens is used under a severe condition such as high temperature and high humidity. For example, the official gazette of Japanese Patent Laid-Open No. 5-41506 discloses a structure in which a microlens is covered with resin and moreover, cover glass for sealing the resin is used.
However, at the time of selecting a sealing resin for covering a microlens by considering heat resistance, transparency, spectral performance, and refractive-index change, it is unavoidable to select a resin almost the same as the material of the microlens and thereby, the refractive index of the sealing resin becomes almost equal to that of the microlens. As a result, problems occur that the condensing effect of the microlens deteriorates and the light reaching the microlens cannot be completely condensed on a photodiode.
Though an action for increasing a refractive index of a microlens or improving a condensing effect by decreasing a refractive index of a sealing resin is taken, it is impossible to solve the problems such as the above heat resistance, transparency, spectral performance, and refractive-index change.
SUMMARY OF THE INVENTION
The present invention is achieved to solve the conventional problems and its object is to provide a solid-state imaging device having a high condensing efficiency even for a structure using a sealing resin.
The 1
st
invention of the present invention (corresponding to claim 1)is a solid-state-imaging device comprising:
a light-receiving portion for receiving light;
a microlens formed on said light-receiving portion and having a predetermined first refractive index;
a thin-film lens formed on the microlens; and
a resin portion formed on the thin-film lens and having a predetermined second refractive index,
wherein the refractive index of the thin-film lens is smaller than the first and second refractive indexes, and
the thin-film lens is made of an inorganic material.
The 2
nd
invention of the present invention (corresponding to claim 2)is a solid-state imaging device comprising:
a light-receiving portion for receiving light.;
a microlens formed on the light-receiving portion and having a predetermined first refractive index;
a thin-film lens formed on the microlens; and
a resin portion formed on the thin-film lens and having a predetermined second refractive index,
wherein the refractive index of the thin-film lens is smaller than the first and second refractive indexes, and
the thin-film lens is a flat member made of resin curved along a curved face of the microlens.
The 3
rd
invention of the present invention (corresponding to claim 3)is the solid-state imaging device according to 1
st
or 2
nd
inventions, wherein the first and second refractive indexes are substantially equal to each other.
The 4
th
invention of the present invention (corresponding to claim 4) is the solid-state imaging device according to 1
st
invention, wherein
the thin-film lens is a lens made of fluoride and/or oxide.
The 5
th
invention of the present invention (corresponding to claim 5) is the solid-state imaging device according to 1
st
or 2
nd
inventions, wherein the microlens is a lens made of resin.
The 6
th
invention of the present invention (corresponding to claim 6) is the solid-state imaging device according to 5
th
invention, wherein
the first and second refractive indexes are close to 1.56 and the refractive index of the thin-film lens ranges between 1.36 or more and 1.50 or less.
The 7
th
invention of the present invention (corresponding to claim 7 to 11)is the solid-state imaging device according to any one of 2
nd
to 6
th
inventions, wherein the thin-film lens is made of resin, the microlens has a diameter of approx. 4000 nm, and the thin-film lens has a thickness of 80 nm or more to 1000 nm or less.
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patent: 6330112 (2001-12-01), Kaise et al.
patent: 2001/0033007 (2001-10-01), Lee
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patent: 5-41506 (1993-02-01), None
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patent: 10-206605 (1998-08-01), None
Patent Abstracts of Japan for Jap. Publ. No. 10229180, published Aug. 25, 1998.
Copy of European Search Report dated May 2, 2002, for EP 00 10 7776.
Flynn Nathan J.
Sefer Ahmed N.
Smith , Gambrell & Russell, LLP
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