Optical element with stress distributing supporting structure
There is presented an optical element 100 , such as a tuneable lens, wherein there is provided means 128 to mitigate problems with stress concentration in a bendable cover member 102 at a border of a supporting structure 101 , which in the absence of said means would entail a stress singularity issue due to an abrupt change in mechanical properties around the bendable cover member 102.
1. An optical element defining an optical axis and comprising:
a supporting structure,
a bendable cover member attached to the supporting structure, wherein an interface between the bendable cover member and the supporting structure defines an interface plane,
one or more actuators arranged for shaping said bendable cover member into a desired shape,
at least one deformable transparent lens body attached to the bendable cover member,
wherein
one or more of:
a dimension in a direction being parallel with the optical axis, and/or
a Young's modulus
of the supporting structure on one side of the interface plane increases gradually and/or in a plurality of steps along at least a portion of a line being orthogonal to the optical axis and intersecting the optical axis and in a direction away from the optical axis, wherein said line spans a range from a point at an inner edge of the interface and a point more distantly placed with respect to the optical axis,
and/or wherein
a dimension of the bendable cover member in a direction being parallel with the optical axis is larger
at at least one first point at an inner edge of the interface, than
at at least one second point on a line from said first point to the optical axis,
and wherein the Young's modulus of the supporting structure is less than the Young's modulus of the bendable cover member.
2. The optical element according to claim 1 , wherein the supporting structure comprises:
a support element, and
a structural element adjoining
the support element, and
the bendable cover member.
3. The optical element according to claim 1 , wherein a dimension of the supporting structure in a direction being parallel with the optical axis of the optical element increases gradually and/or in a plurality of steps along a line orthogonal to the optical axis from the optical axis and away from the optical axis.
4. The optical element according to claim 2 , wherein a material of the structural element is different from
a material of the support element, and
a material of the bendable cover member.
5. The optical element according to claim 2 , wherein the structural element comprises a polymer.
6. The optical element according to claim 2 , wherein the structural element comprises epoxy.
7. The optical element according to claim 1 , wherein the optical element is a refractive lens comprising:
said at least one deformable transparent lens body surrounded by a sidewall of the supporting structure,
and wherein the bendable cover member is a bendable transparent cover member which is attached to
a surface of said at least one deformable transparent lens body.
8. The optical element according to claim 1 , wherein the one or more actuators and the bendable cover member are arranged so that the one or more actuators upon actuation are capable of shaping the bendable cover member throughout a range of 5 dioptres or more.
9. The optical element according to claim 1 , wherein the plurality of steps comprise at least 3 steps.
10. The optical element according to claim 1 , wherein at least a portion of the supporting structure of which the dimension in the direction being parallel with the optical axis, and/or
the Young's modulus increases gradually and/or in a plurality of steps is located separated from the at least one deformable transparent lens body.
11. A method of manufacturing the optical element according to claim 1 comprising:
providing the optical element of claim 2 ; and
placing a liquid structural element material at the support element, and/or the bendable
cover member, so as to form the structural element.
12. The method according to claim 2 , wherein the liquid structural element material is redistributed via adhesive forces between the liquid structural element material and
the support element, and/or
the bendable cover member
beyond the position where it is placed.
13. A camera comprising
an optical element according to claim 1 .