Light scanning apparatus
A light scanning apparatus for causing a mirror to oscillate to scan with light reflected by the mirror includes an interconnect formed of gold; a protective film for covering the interconnect; and an adhesive film formed between the interconnect and the protective film.
1. A light scanning apparatus for causing a mirror to oscillate to scan with light reflected by the mirror, the light scanning apparatus comprising:
an insulating film;
a base film disposed on the insulating film, and including titanium;
an interconnect disposed on the base film, the interconnect being formed of gold;
a protective film for covering the interconnect; and
an adhesive film formed between the interconnect and the protective film,
wherein the interconnect includes an end portion, the end portion including a region that serves as a terminal, and the end portion having a surface exposed through an opening that is provided by removing both a portion of the adhesive film and a portion of the protective film,
wherein the adhesive film includes a first edge surface, and the protective film includes a second edge surface,
wherein the first edge surface and the second edge surface are obtained with the removal of the portion of the adhesive film and the portion of the protective film,
wherein the first edge surface is aligned with the second edge surface as viewed in a direction perpendicular to an exposed surface of the end portion in the interconnect,
wherein the protective film is formed of an inorganic oxide,
wherein the adhesive film includes titanium that is oxidized with the inorganic oxide in the protective film to form a compound, the compound bonding with oxygen that is included in the inorganic oxide,
wherein the adhesive film is coupled to the interconnect upon occurrence of a condition in which the titanium in the adhesive film is diffused into the gold in the interconnect, and
wherein the base film contacts the insulating film and the interconnect.
2. The light scanning apparatus according to claim 1 , wherein the adhesive film has a coefficient of thermal expansion that is a value between a coefficient of thermal expansion of the interconnect and a coefficient of thermal expansion of the protective film.
3. The light scanning apparatus according to claim 1 , wherein the adhesive film is formed of titanium tungsten.
4. The light scanning apparatus according to claim 1 , wherein the protective film is formed of aluminum oxide.
5. The light scanning apparatus according to claim 1 , wherein the interconnect is a drive interconnect electrically coupled to a piezoelectric element as a drive source that drives the mirror.
6. The light scanning apparatus according to claim 1 , wherein the interconnect is a sensor interconnect electrically coupled to a sensor that outputs a signal according to an angle at which the mirror is oriented.
7. The light scanning apparatus according to claim 1 , further comprising:
a mixed region at a first interface where the interconnect contacts the adhesive film, the mixed region including the gold constituting the interconnect and a material included in the adhesive film; and
a region at a second interface where the protective film contacts the adhesive film, the region including the compound,
wherein the adhesive film has a coefficient of thermal expansion that is a value between a coefficient of thermal expansion of the interconnect and a coefficient of thermal expansion of the protective film.