Projector and projector control method

• US 8,297,757 B2
• Filed: 10/26/2009
• Issued: 10/30/2012
• Est. Priority Date: 10/29/2008
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Kubota, Shinji
• Primary Examiner(s): Lee, John
• Application Number:
  US12/605,916
• Publication Number:
  US 20100103386A1
• Time in Patent Office: 1,100 Days
• Field of Search: 353/69, 353/70, 353/121
• US Class Current: 353/70
• CPC Class Codes: G03B 21/14 Details
• CPC Class Codes: H04N 9/3185 Geometric adjustment, e.g. keystone or convergence optical or mechanical adjustment of convergence H04N9/317; using scanning means H04N3/22; optical or mechanical adjustments of projectors not peculiar to the presence of an electronic spatial light modulator G03B21/14
• CPC Class Codes: H04N 9/3194 including sensor feedback

Abstract

A projector which projects an image onto a projection surface, and displays it thereon, includes: a light source; a light modulator which modulates light from the light source into an image light representing the image; a projection optical system which projects the image light modulated by the light modulator onto the projection surface; a keystone distortion correction section which carries out a keystone distortion correction process for correcting a keystone distortion of the image projected onto the projection surface; a detection section which detects a stop of a movement of the projector; and a control section which, on the stop of the movement of the projector being detected in the detection section, causes the keystone distortion correction section to start the keystone distortion correction process in accordance with a relative positional relationship between the projector after being moved and the projection surface.

Claims

1. A projector which projects an image onto a projection surface, and displays it thereon, comprising:

a light source;

a light modulator which modulates light from the light source into an image light representing the image;

a projection optical system which projects the image light modulated by the light modulator on the projection surface;

a keystone distortion correction section which carries out a keystone distortion correction process for correcting a keystone distortion of the image projected onto the projection surface;

a detection section which detects a stop of a movement of the projector; and

a control section which, on the stop of the movement of the projector being detected in the detection section, causes the keystone distortion correction section to start the keystone distortion correction process in accordance with a relative positional relationship between the projector after being moved and the projection surface, wherein

the detection section includes an angular velocity sensor which detects an angular velocity of the projector and the detection section detects the stop of the movement of the projector in the event that a predetermined time has elapsed in a condition in which the angular velocity detected by the angular velocity sensor, after exceeding a first value set in advance, becomes lower than a second value which is lower than the first value, and maintains a value lower than the second value.

2. The projector according to claim 1, further comprising:

an autofocus section which automatically adjusts a focus in the projection optical system in such a way that an image is formed on the projection surface, wherein

the control section, on the stop of the movement of the projector being detected, causes the autofocus section to start the adjustment of the focus.

3. The projector according to claim 1, wherein

the detection section detects the start of the movement of the projector, and

the control section, when the start of the movement of the projector is detected in the detection section, cancels the keystone distortion correction process in the keystone distortion correction section.

4. The projector according to claim 3, further comprising:

a storage section in which guide pattern data are stored, the guide pattern data representing a guide pattern which shows the center of a maximum area of the light modulator in which the light from the light source can be modulated, wherein

the control section, as well as canceling the keystone distortion correction process in the keystone distortion correction section, causes the light modulator to generate an image light representing the guide pattern based on the guide pattern data stored in the storage section.

5. A projector which projects an image onto a projection surface, and displays it thereon, comprising:

a light source;

a light modulator which modulates light from the light source into an image light representing the image;

a projection optical system which includes an autofocus section for automatically adjusting a focus in such a way that the image light modulated by the light modulator is imaged on the projection surface;

a detection section which detects a stop of a movement of the projector; and

a control section which, on the stop of the movement of the projector being detected in the detection section, causes the autofocus section to start the adjustment of the focus, wherein

the detection section includes an angular velocity sensor which detects an angular velocity of the projector and the detection section detects the stop of the movement of the projector in the event that a predetermined time has elapsed in a condition in which the angular velocity detected by the angular velocity sensor, after exceeding a first value set in advance, becomes lower than a second value which is lower than the first value, and maintains a value lower than the second value.

6. The projector according to claim 5, further comprising:

a keystone distortion correction section which carries out a keystone distortion correction process for correcting a keystone distortion of the image projected onto the projection surface, wherein

the control section, on the stop of the movement of the projector being detected in the detection section, causes the keystone distortion correction section to start the keystone distortion correction process in accordance with a relative positional relationship between the projector after being moved and the projection surface.

7. The projector according to claim 6, wherein

the detection section detects the start of the movement of the projector, and

the control section, when the start of the movement of the projector is detected in the detection section, cancels the keystone distortion correction process in the keystone distortion correction section.

8. The projector according to claim 7, further comprising:

a storage section in which guide pattern data are stored, the guide pattern data representing a guide pattern which shows the center of a maximum area of the light modulator in which the light from the light source can be modulated, wherein

the control section, as well as canceling the keystone distortion correction process in the keystone distortion correction section, causes the light modulator to generate an image light representing the guide pattern based on the guide pattern data stored in the storage section.

9. A projector which projects an image onto a projection surface, and displays it thereon, comprising:

a light source;

a light modulator which modulates light from the light source into an image light representing the image;

a projection optical system which includes an autofocus section for automatically adjusting a focus in such a way that the image light modulated by the light modulator is imaged on the projection surface;

a keystone distortion correction section which carries out a keystone distortion correction process for correcting a keystone distortion of the image projected onto the projection surface;

a detection section which detects a stop of a movement of the projector; and

a control section which, on the stop of the movement of the projector being detected in the detection section, as well as causing the keystone distortion correction section to start the keystone distortion correction process in accordance with a relative positional relationship between the projector after being moved and the projection surface, causes the autofocus section to start the adjustment of the focus, wherein

the detection section includes an angular velocity sensor which detects an angular velocity of the projector and the detection section detects the stop of the movement of the projector in the event that a predetermined time has elapsed in a condition in which the angular velocity detected by the angular velocity sensor, after exceeding a first value set in advance, becomes lower than a second value which is lower than the first value, and maintains a value lower than the second value.

10. The projector according to claim 9, wherein

the detection section detects the start of the movement of the projector, and

the control section, when the start of the movement of the projector is detected in the detection section, cancels the keystone distortion correction process in the keystone distortion correction section.

11. The projector according to claim 10, further comprising:

a storage section in which guide pattern data are stored, the guide pattern data representing a guide pattern which shows the center of a maximum area of the light modulator in which the light from the light source can be modulated, wherein

the control section, as well as canceling the keystone distortion correction process in the keystone distortion correction section, causes the light modulator to generate an image light representing the guide pattern based on the guide pattern data stored in the storage section.

12. A method of controlling a projector which projects an image on a projection surface, and displays it thereon, comprising:

(a) detecting a stop of a movement of the projector by detecting the stop of the movement of the projector when a predetermined time has elapsed in a condition in which a detected angular velocity of the projector, after exceeding a first value set in advance, becomes lower than a second value which is lower than the first value, and maintains a value lower than the second value; and

(b) on the stop of the movement of the projector being detected, starting a keystone distortion correction process for correcting a keystone distortion of the image projected onto the projection surface in accordance with a relative positional relationship between the projector after being moved and the projection surface.

13. The method according to claim 12, wherein the step (b) further comprises:

(b1) initializing a keystone correction amount which is a parameter used for the keystone distortion correction process;

(b2) projecting a plurality of distance detection patterns which are used for detecting a distance from the projector to the projection surface;

(b3) measuring distances from the projector to a plurality of points on a screen by using the plurality of distance detection patterns;

(b4) calculating a tilt of the projector with respect to the projection surface in accordance with the measured distances; and

(b5) calculating the keystone correction amount in accordance with the tilt of the projector.

14. The method according to claim 13, the projector controlled by the method including a focus lens for adjusting a focus in such a way that the image is focused on the projection surface, the method further comprising:

(c) measuring a distance from the projector to the center of the screen;

(d) calculating a position of the focus lens in accordance with the distance from the projector to the center of the screen; and

(e) moving the focus lens to the calculated position of the focus lens.