Optical device and optical apparatus having the same

An optical apparatus comprising:

• an optical device including first and second optical elements formed of mutually different materials and a bonding member bonding the first and second optical elements to each other;
• and
• a holding member holding the optical device,
• wherein the following conditional expression is satisfied:
• 0.14<Log(te/tc)×Log(E1×E2/Ec2)<5.0
• where tc is a thickness in an optical axis direction of the bonding member on an optical axis, te is a thickness in the optical axis direction of the bonding member in a maximum diameter of interfaces between the first and second optical elements and the bonding member, and E1, E2, and Ec are respective Young's moduli of the first and second optical elements and the bonding member.

An optical device comprising:

• first and second optical elements formed of mutually different materials;
• and
• a bonding member bonding the first and second optical elements to each other,
• wherein the following conditional expression is satisfied:
• 1.3<te/tc/{1−0.6(Dc/2Rc)2}<15
• where tc is a thickness in an optical axis direction of the bonding member on an optical axis, te is a thickness in the optical axis direction of the bonding member in a maximum diameter of interfaces between the first and second optical elements and the bonding member, Rc is an average of curvature radii of the interfaces between the first and second optical elements and the bonding member, and Dc is the maximum diameter of the interfaces between the first and second optical elements and the bonding member.