US 5,150,234 A · Imaging apparatus having electrooptic devices comprising a variable focal length lens

Abstract

An imaging apparatus is provided with a negative lens, a variable focussing lens unit including a material with an electrooptic effect, a light blocking unit, including the material with the electrooptic effect, capable of changing an aperture diameter, and a switch, interlocked with each other, capable of supplying electric power to the variable focussing lens unit and the light blocking unit which are arranged in order on an optical axis from an object side to an image side. When the switch is turned off, the variable focussing lens unit is set to bring an object at a far point into focus and the light blocking unit is set so that an aperture is determined by an aperture stop, while on the other hand, when the swtich is turned on, the variable focussing lens unit is set so that an object at a near point is in focus and the light blocking unit is set to be smaller in aperture. Apertures different in size are determined by a plurality of annular transparent electrodes incorporated in the light blocking unit and configured concentrically. Thus the imaging apparatus can be constructed to be small or compact in size and is easy in manufacturing.

Claims14

Dependent claims

An imaging apparatus having electrooptic devices, comprising:

first and second circularly polarizing means having first and second states of operation and disposed on an optical axis, said first and second circularly polarizing means in spaced relation having a space therebetween, in said first state circularly polarized light of one direction is transmitted and in said second state all circularly polarized light is transmitted;
first and second 1/4 wave plates disposed on said optical axis in said space between said first and second circularly polarizing means;
a variable focal length lens containing a material having an electrooptic effect, disposed on said optical axis between said first and second 1/4 wave plates;
a light blocking member having an aperture on said optical axis;
and
power source means for actuating in synchronization said first and second circularly polarizing means and said variable focal length lens,
one of said first and second circularly polarizing means being provided with a central transparent part smaller in diameter than said aperture of said light blocking member, said first circularly polarizing means, said first 1/4 wave plate, said light blocking member, said second 1/4 wave plate and said second circularly polarizing means functioning as light blocking means for changing an aperture thereof to different sizes.

4 more elements

An imaging apparatus having electrooptic devices, comprising:

circularly polarizing means having two states of operation, in a first state circularly polarized light of one direction is transmitted and in a second state all circularly polarized light is transmitted;
a polarizing plate spaced away from said circularly polarizing means;
a variable focal length lens containing a material having an electrooptic effect and disposed on an optical axis between said circularly polarizing means and said polarizing plate;
a 1/4 wave plate disposed on said optical axis between said variable focal length lens and said circularly polarizing means;
a light blocking member having an aperture on said optical axis;
and
power source means for actuating in synchronization said circularly polarizing means and said variable focal length lens,
one of said circularly polarizing means and said polarizing plate being provided with a center area smaller in diameter than said aperture of said light blocking member, said circularly polarizing means, said 1/4 wave plate, said light blocking means and said polarizing plate functioning as light blocking means for changing an aperture thereof to different sizes.

5 more elements

Dependencies are inferred from the claim text.

Imaging apparatus having electrooptic devices comprising a variable focal length lens

Life of this patent

Imaging apparatus having electrooptic devices comprising a variable focal length lens

Life of this patent

Abstract

Claims14