JP2012014126A5

JP2012014126A5 -

Info

Publication number: JP2012014126A5
Application number: JP2010153447A
Authority: JP
Filing date: 2010-07-05
Publication date: 2013-08-29
Anticipated expiration: 2030-07-05

Description

このような目的達成のため、本発明を例示する態様に従えば、映像表示素子に表示された映像を拡大して所定の投写面に斜め方向から投写する映像投写装置用光学系であって、光軸に沿って前記映像表示素子側から順に並んだ、中心軸に対して回転対称に形成された回転対称レンズからなる回転対称レンズ群と、中心軸に対して非回転対称に形成された複数の自由曲面レンズからなる自由曲面レンズ群と、中心軸に対して非回転対称に形成された反射面を有する自由曲面ミラーとを有し、前記自由曲面レンズ群の中で前記自由曲面ミラーに最も近い自由曲面レンズにおける両側のレンズ面のうち少なくとも一方において、前記映像表示素子から前記自由曲面ミラーへ向かう方向を正とする光軸方向の座標軸をz軸とし、前記断面に沿って前記z軸と垂直な座標軸をy軸とし、前記z軸および前記y軸と垂直な座標軸をx軸として、前記自由曲面レンズのレンズ面と光軸との交点を原点とするローカル座標系（x，y，z）を定義し、前記レンズ面の形状を表わす式をz＝f(x，y)としたとき、前記映像表示素子からの光が通過する領域内において、後述の（１）式を満足するf(0，α)が存在し、前記レンズ面の形状を表わす式に対しy´＝y−αとする変数変換を行った式をz＝f´(x，y´)としたとき、x＝0において、後述の（２）式を満足することを特徴とする映像投写装置用光学系が提供される。 In order to achieve such an object, according to an aspect of the present invention, an optical system for an image projection apparatus that enlarges an image displayed on an image display element and projects the image on a predetermined projection surface from an oblique direction, A rotationally symmetric lens group composed of rotationally symmetric lenses formed in a rotationally symmetric manner with respect to the central axis and arranged in order from the image display element side along the optical axis, and a plurality of non-rotationally symmetric lenses formed with respect to the central axis A free-form surface lens group composed of a free-form surface lens and a free-form surface mirror having a reflection surface formed non-rotationally symmetric with respect to the central axis, and the most free-form surface mirror in the free-form surface lens group In at least one of the lens surfaces on both sides of the near free-form surface lens, the coordinate axis in the optical axis direction in which the direction from the image display element toward the free-form surface mirror is positive is the z-axis, and the z-axis is along the cross section. A local coordinate system (x, y, x, y), where the coordinate axis perpendicular to the axis is the y axis, the coordinate axis perpendicular to the z axis and the y axis is the x axis, and the intersection of the lens surface of the free-form surface lens and the optical axis is the origin z) is defined, and the expression representing the shape of the lens surface is z = f (x, y), the following expression (1) is satisfied in the region through which the light from the image display element passes. When f (0, α) exists and z = f ′ (x, y ′) is an expression obtained by performing variable transformation with y ′ = y−α on the expression representing the shape of the lens surface, x = 0, an optical system for an image projection apparatus is provided that satisfies the following expression (2) .

Claims

An optical system for an image projection apparatus that enlarges an image displayed on an image display element and projects the image on a predetermined projection surface from an oblique direction,
A rotationally symmetric lens group composed of rotationally symmetric lenses formed in a rotationally symmetric manner with respect to the central axis and arranged in order from the image display element side along the optical axis, and a plurality of non-rotationally symmetric lenses formed with respect to the central axis A free-form surface lens group consisting of a free-form surface lens, and a free-form surface mirror having a reflection surface formed non-rotationally symmetric with respect to the central axis,
In at least one of the lens surfaces on both sides of the free-form surface lens closest to the free-form surface mirror in the free-form surface lens group , the coordinate axis in the optical axis direction in which the direction from the image display element toward the free-form surface mirror is positive Is the z axis, the coordinate axis perpendicular to the z axis along the cross section is the y axis, and the coordinate axis perpendicular to the z axis and the y axis is the x axis, the lens surface of the free-form surface lens and the optical axis When a local coordinate system (x, y, z) having an intersection point as an origin is defined and the expression representing the shape of the lens surface is z = f (x, y), light from the image display element passes through. Within the area,

F (0, α) satisfying the above condition exists, and z = f ′ (x, y ′) is an expression obtained by performing variable transformation with y ′ = y−α on the expression representing the shape of the lens surface. When x = 0,

An optical system for an image projection apparatus, characterized by satisfying the following conditions .

When y = 0, in the region where the light from the image display element passes,

The optical system for an image projection apparatus according to claim 1 , wherein the following condition is satisfied.

3. The image projection according to claim 1 , wherein at least one of both lens surfaces of the free-form surface lens closest to the free-form surface mirror is both of the lens surfaces on both sides of the free-form surface lens. Optical system for equipment.

A first free-form surface lens having a convergence effect, a second free-form surface lens having a divergence effect, and a third having a convergence effect, wherein the free-form surface lens group is arranged in order from the image display element side along the optical axis. The optical system for an image projection apparatus according to any one of claims 1 to 3 , wherein the optical system includes a free-form surface lens.

5. The optical system for an image projection apparatus according to claim 1, wherein a central axis of the rotationally symmetric lens group is inclined with respect to an optical axis.

An optical system for an image projection apparatus that enlarges an image displayed on an image display element and projects the image on a predetermined projection surface from an oblique direction,
A rotationally symmetric lens group composed of rotationally symmetric lenses formed in a rotationally symmetric manner with respect to the central axis and arranged in order from the image display element side along the optical axis, and a plurality of non-rotationally symmetric lenses formed with respect to the central axis A free-form surface lens group consisting of a free-form surface lens, and a free-form surface mirror having a reflection surface formed non-rotationally symmetric with respect to the central axis,
In at least one of the lens surfaces on both sides of the free-form surface lens closest to the free-form surface mirror in the free-form surface lens group, the coordinate axis in the optical axis direction that is positive in the direction from the image display element to the free-form surface mirror is z An axis that is perpendicular to the z-axis along the cross section of the free-form surface lens passing through the optical axis between the free-form surface lens group and the free-form surface mirror and the optical axis between the free-form surface mirror and the projection surface. A local coordinate system (x, y, z) in which the coordinate axis perpendicular to the z axis and the y axis is the x axis, and the intersection of the lens surface of the free-form surface lens and the optical axis is the origin Where m and n are natural numbers including 0, and C (m, n) is a coefficient of an xy polynomial, and an expression representing the sag amount of the lens surface is

When expressed as

And the following formula

An optical system for an image projection apparatus, characterized by satisfying the following conditions.

The coordinate axis in the optical axis direction that is positive in the direction from the image display element to the free-form curved mirror is the z axis, the coordinate axis perpendicular to the z axis along the cross section is the y axis, and the z axis and the y axis Defining a local coordinate system (x, y, z) with the origin of the intersection of the lens surface of the free-form surface lens and the optical axis, with the coordinate axis perpendicular to the x axis as the x axis,
In the free-form surface lens closest to the free-form surface mirror, let L be an air conversion distance between the lens surface on the free-form surface mirror side and the aperture stop, and the following formula

And the following formula

Define
When the sag amount of the lens surface on the free-form surface mirror side of the free-form surface lens closest to the free-form surface mirror is z,
In the cross section of the free-form surface lens when y = 0,

Where x> r _a

Satisfy the conditions of
In the cross section of the free-form surface lens when x = 0,

Where y> r _a

The image projection apparatus optical system according to claim 6 , wherein the following condition is satisfied.

An image projection device that is used in a state where it is installed on a predetermined installation surface and projects an image from an oblique direction on the same surface as the installation surface or a surface substantially parallel to the installation surface, the image projection device An image projection apparatus, wherein the optical system is the optical system for an image projection apparatus according to any one of claims 1 to 7 .