Display apparatus and image pickup apparatus

A display apparatus comprising:

• an image display element;
• an eyepiece portion;
• an object window;
• and
• a mirror disposed at a position between the eyepiece portion and the object window, the mirror being configured to guide a picture displayed on the image display element to the eyepiece portion,
• wherein the mirror changes a state to a first state and to a second state by changing a transmittance,
• wherein in the first state, the picture displayed on the image display element is viewed via the eyepiece portion,
• wherein in the second state, an image in which an image from the object window and an image displayed on the image display element are superimposed is viewed via the eyepiece portion,
• wherein the mirror includes a first mirror having a planar surface shape, and a second mirror having a curved surface shape,
• wherein in the first state, the first mirror is in a total reflection state, and the second mirror is in a total transmission state, and
• wherein in the second state, the first mirror is in a total transmission state, and the second mirror is in a half transmission state.

A display apparatus comprising:

• an image display element;
• an eyepiece portion;
• an object window;
• a mirror disposed at a position between the eyepiece portion and the object window, the mirror being configured to guide a picture displayed on the image display element to the eyepiece portion;
• and
• a position detector configured to detect a position of a user's eye ball relative to the eyepiece portion by detecting a reflection of light projected on the user's eye ball,
• wherein the mirror changes a state to a first state and to a second state by changing a transmittance,
• wherein in the first state, the picture displayed on the image display element is viewed via the eyepiece portion,
• wherein in the second state, an image in which an image from the object window and an image displayed on the image display element are superimposed is viewed via the eyepiece portion,
• wherein the mirror has a planar surface shape, and
• wherein in the second state, the mirror moves a position of the image displayed on the image display element, based on the position of the eye ball detected by the position detector.

A display apparatus comprising:

• an image display element;
• an eyepiece portion;
• an objeet window;
• a mirror disposed at a position between the eyepiece portion and the object window, the mirror being configured to guide a picture displayed on the image display element to the eyepiece portion;
• an enlargement lens disposed at a position between the mirror and the eyepiece portion, the enlargement lens being configured to enlarge the picture;
• and
• a reduction lens disposed at a position between the object window and the mirror, the reduction lens being configured to reduce the image from the object window,
• wherein the mirror changes a state to a first state and to a second state by changing a transmittance,
• wherein in the first state, the picture displayed on the image display element is viewed via the eyepiece portion,
• wherein in the second state, an image in which an image from the object window and an image displayed on the image display element are superimposed is viewed via the eyepiece portion, and
• wherein a reciprocal of an enlargement magnification of the enlargement lens is the same as a reduction magnification of the reduction lens.

A display apparatus comprising:

• an image display element;
• an eyepiece portion;
• an object window;
• and
• a mirror disposed at a position between the eyepiece portion and the object window, the mirror being configured to guide a picture displayed on the image display element to the eyepiece portion,
• wherein the mirror changes a state to a first state and to a second state by changing a transmittance,
• wherein in the first state, the picture displayed on the image display element is viewed via the eyepiece portion,
• wherein in the second state, an image in which an image from the object window and an image displayed on the image display element are superimposed is viewed via the eyepiece portion, and
• wherein the display apparatus further comprises:
• an enlargement lens configured to enlarge the picture;
• and
• an actuator configured to drive the enlargement lens so that (a) in the first state, the enlargement lens is disposed at a position between the mirror and the eyepiece portion, and (b) in the second state, the enlargement lens retracts from the position between the mirror and the eyepiece portion.

A display apparatus comprising:

• an image display element;
• an eyepiece portion;
• an object window;
• and
• a mirror disposed at a position between the eyepiece portion and the object window, the mirror being configured to guide a picture displayed on the image display element to the eyepiece portion,
• wherein the mirror changes a state to a first state and to a second state by changing a transmittance,
• wherein in the first state, the picture displayed on the image display element is viewed via the eyepiece portion,
• wherein in the second state, an image in which an image from the object window and an image displayed on the image display element are superimposed is viewed via the eyepiece portion, and
• wherein the display apparatus further comprises:
• a shape-variable lens disposed at a position between the mirror and the eyepiece portion, the shape-variable lens having a variable shape;
• and
• a deformation unit including various actuators, configured to deform a shape of the shape-variable lens so that (a) in the first state, the picture is enlarged, and (b) in the second state, magnification variation on the image from the object window is not performed.