# US 7,609,458 B2 · Projection apparatus, elevation angle control method therefor and recording medium

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- Number: US 7,609,458 B2
- Document ID: US7609458B2
- Status: Granted
- Kind: B2
- Application number: 11/655,481
- Filed: 2007-01-19
- Published: 2007-07-26
- Granted: 2009-10-27
- Earliest claimed: 2006-01-20
- Assignees: Casio Computer Co., Ltd.
- Inventors: Hideaki Inoue
- Web page: https://patentgrep.com/patent/US7609458B2

## CPC

- G03B 21/56: Projection screens
- G03B 21/147: {Optical correction of image distortions, e.g. keystone}
- G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D)

## Abstract

A projection apparatus includes a distance measuring unit that measures a distance to a screen on which an image is to be projected; a projection unit that has a zoom mechanism unit capable of changing a zoom magnification of a projection image, executes focusing based on the distance measured by the distance measuring unit and projects an image on the screen; and an elevation angle control unit that controls an elevation angle of the distance measuring unit based on the zoom magnification set by the zoom mechanism unit in such a way that a distance measuring center line of the distance measuring unit corresponds to a center point of a projection area of the projection image, wherein the center point of a projection area is determined according to the zoom magnification of the zoom mechanism unit.

## Claims

### Claim 1

A projection apparatus comprising:
a distance measuring unit that measures a distance to a screen on which an image is to be projected;
a projection unit that has a zoom mechanism unit capable of changing zoom magnifications of a projection image, focuses the projection image based on the distance measured by the distance measuring unit and projects the image on the screen; and
an elevation angle control unit that controls an elevation angle of the distance measuring unit based on the zoom magnification set by the zoom mechanism unit in such a way that a distance measuring center line of the distance measuring unit corresponds to a center point of a projection area of the projection image, wherein the center point of the projection area is determined according to the zoom magnification of the zoom mechanism unit.

### Claim 2 (depends on 1)

The projection apparatus according to claim 1, further comprising an operation unit for acquiring designated zoom magnification information,
wherein the elevation angle control unit supplies the zoom magnification information acquired by the operation unit to the zoom mechanism unit, and controls the elevation angle of the distance measuring unit based on the zoom magnification information.

### Claim 3 (depends on 1)

The projection apparatus according to claim 1, further comprising a storage unit that stores relationship information between the zoom magnification and the elevation angle of the distance measuring unit,
wherein the elevation angle control unit controls the elevation angle of the distance measuring unit based on an elevation angle acquired by referring to the relationship information stored in the storage unit based on the zoom magnification set by the zoom mechanism unit.

### Claim 4 (depends on 1)

The projection apparatus according to claim 1, wherein the projection unit comprises a projection lens which projects an image on the screen, and a line passing through a tip of the projection lens of the projection unit and through the center point of the projection area of the image projected onto the screen, and an optical axis of the projection lens of the projection unit form a predetermined angle.

### Claim 5

A projection apparatus comprising:
a distance measuring unit that measures a distance to a screen on which an image is to be projected; and
a projection unit that has a zoom mechanism unit capable of changing zoom magnifications of a projection image, focuses the projection image based on the distance measured by the distance measuring unit and projects the image on the screen; and
the zoom mechanism unit of the projection unit controls a distance measuring range of the distance measuring unit in such a way that a center point of the distance measuring range of the distance measuring unit corresponds to a center point of a projection area of the projection image, wherein the projection area is determined according to the set zoom magnification.

### Claim 6 (depends on 5)

The projection apparatus according to claim 5, further comprising an operation unit for acquiring designated zoom magnification information,
wherein the zoom mechanism unit sets the zoom magnification and controls the zoom magnification according to the zoom magnification information acquired by the operation unit.

### Claim 7 (depends on 5)

The projection apparatus according to claim 5, wherein the projection unit comprises a projection lens which projects an image on the screen, and a line passing through a tip of the projection lens of the projection unit and through the center point of the projection area of the image projected onto the screen, and an optical axis of the projection lens of the projection unit form a predetermined angle.

### Claim 8

An elevation angle control method for a projection apparatus which projects an image on a screen, comprising the steps of:
setting a zoom magnification when projecting the image on the screen; and
controlling an elevation angle of a distance measuring center line in such a way that a distance measuring center line extending to the screen corresponds to a center point of a projection area of a projection image to be determined according to the set zoom magnification.

### Claim 9

A computer readable recording medium storing a program for allowing a computer to execute:
a procedure of setting a zoom magnification when projecting the image on the screen; and
controlling an elevation angle of a distance measuring center line in such a way that a distance measuring center line extending to the screen corresponds to a center point of a projection area of a projection image to be determined according to the set zoom magnification.

### Claim 10

A projection apparatus comprising:
a distance measuring unit that measures a distance to a screen on which an image is to be projected; and
a projection unit that comprises a zoom mechanism unit capable of changing zoom magnifications of a projection image, focuses the projection image based on the distance measured by the distance measuring unit, and projects the image on the screen; and
the zoom mechanism unit of the projection unit that controls a distance measuring area of the distance measuring unit in such a way that the distance measuring area of the distance measuring unit approaches the projection area of the projection image, wherein the projection area is determined according to the set zoom magnification.