Image projector and image projecting method

• US 7,364,309 B2
• Filed: 06/10/2003
• Issued: 04/29/2008
• Est. Priority Date: 06/10/2002
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Eguchi, Naoya, Sugawara, Yutaka
• Primary Examiner(s): Dowling; William C.
• Application Number:
  US10/486,055
• Publication Number:
  US 20050128578A1
• Time in Patent Office: 1,785 Days
• Field of Search: 353/85, 353/97, 353/122
• US Class Current: 353/85
• CPC Class Codes: G03B 21/005 Projectors using an electronic spatial light modulator but not peculiar thereto
• CPC Class Codes: G03B 21/2086 Security or safety means in lamp houses
• CPC Class Codes: H04N 5/57 Control of contrast or brightness
• CPC Class Codes: H04N 5/74 Projection arrangements for image reproduction, e.g. using eidophor
• CPC Class Codes: H04N 9/3129 scanning a light beam on the display screen scanning a light beam on a screen in displays other than projection devices G09G3/02; scanning systems in general G02B26/10; projectors using laser light sources in general H04N9/3161
• CPC Class Codes: H04N 9/3179 Video signal processing therefor

Abstract

In an image projection on a screen, an image projection apparatus improves the safety of entry into a projection region by the human body and does not bring about the increase of complexity of the configuration thereof owing to the improvement of the safety. A monitoring area is regulated on the outside of the projection area (3) of the screen (2). A detection wave such as infrared rays is emitted from a detection wave source (1c) of the image projection apparatus (1). A reflection wave from the monitoring area is detected by reflection wave detection means (1d) such as a CCD sensor. Whether the human body or an obstacle enters the monitoring space, which is surrounded by a detection wave (4) between the main body unit of the image projection apparatus (1) and the screen (2), or not is detected. Once the entry is detected, the intensity of the radiation light traveling toward the projection area (3) is reduced or cut off according to the situation or the degree of the entry.

Claims

1. An image projection apparatus comprising a light source and projection unit for performing an image display by projection to a projection area on a screen, and a safety mechanism against entry into a passage area of a radiation light from said projection unit toward said projection area, comprising:

a detection wave source provided on an opposed plane of an apparatus main body unit to said screen or on said screen; and

reflection wave detection means for detecting a reflection wave reflected in a monitoring area, which is located on an outside of said projection area at a distance, after a detection wave is emitted from said detection wave source toward said monitoring area,

wherein entry into a monitoring space surrounded by said detection wave, which is arranged so as to wholly surround the radiation light that has been emitted from the projection unit, is detected on a basis of a result of a comparison of a detected level by said reflection wave detection means with a threshold value or a reference region, and

wherein said reflection wave detection means comprises;

first detection means for detecting said entry into said monitoring space;

second detection means for detecting entry into a monitoring space including an area outside of said monitoring space;

first alarm means for performing an alarm process if said entry is detected by said first detection means; and

second alarm means for performing an alarm process if said entry is detected by said second detection means.

2. The image projection apparatus according to claim 1, wherein said detection wave source or said reflection wave detection means is arranged around said projection unit provided on said opposed plane to said screen.

3. The image projection apparatus according to claim 1, wherein said detection wave is an infrared light or an infrared ray.

4. The image projection apparatus according to claim 3, wherein said reflection wave detection means is composed of an image sensor, and said monitoring area is monitored on a basis of detected image data by said image sensor, and a width of said monitoring area is made to be narrower than an area projected on said screen by said detection wave source.

5. The image projection apparatus according to claim 1, wherein if entry into said monitoring space is detected, a radiation light from said light source to said projection area is cut off or intensity of said radiation light is reduced.

6. The image projection apparatus according to claim 1, further comprising:

optical modulation means for modulating emission light from said light source according to an image signal;

light projection means for projecting said light modulated by said optical modulation means to said projection area on said screen; and

entry detection means for detecting entry into said monitoring space,

wherein, if said entry into said monitoring space is detected by said entry detection means, said radiation light from said light source to said projection area is cut off or intensity of said radiation light is reduced according to an entry state.

7. The image projection apparatus according to claim 6, wherein if said entry into said monitoring space is detected by said entry detection means, light emitted from said light source is cut off.

8. The image projection apparatus according to claim 6, wherein if said entry into said monitoring space is detected by said entry detection means, electric power to be supplied to said light source is reduced or set to be zero.

9. The image projection apparatus according to claim 6, wherein if said entry into said monitoring space is detected by said entry detection means, a drive of said optical modulation means is stopped.

10. The image projection apparatus according to claim 8, wherein said electric power to be supplied to said light source is controlled according to a duration of said entry into said monitoring space or the area of a part entered.

11. The image projection apparatus according to claim 1, wherein said reflection wave detection means measures intensity of said reflection wave from said screen on a basis of respective pixel data of said monitoring area, and compares intensity of detection wave reflected at a time of entry into said monitoring space with reflection intensity from said monitoring area in case of said entry does not exist, and said entry is detected if both of said intensity differ from each other.

12. The image projection apparatus according to claim 1, wherein an image is projected with said intensity of said radiation light reduced to a level safe for the human body until no detection of any entry into said monitoring space is confirmed, and after said confirmation, said intensity of said radiation light rises to a preset level.

13. The image projection apparatus according to claim 1, wherein if said first detection means detects said entry, said radiation light from said light source toward said projection area is cut off or said intensity of said radiation light is reduced to a level which is not dangerous for human body.

14. An image projection method comprising:

setting a monitoring area, which is located on an outside of a projection area on a screen, for said screen located at a distance from an image projection apparatus;

emitting a detection wave from a detection wave source provided on a front plane of said image projection apparatus toward said monitoring area;

detecting entry into a monitoring space surrounded by said detection wave, which is arranged so as to wholly surround the radiation light that has been emitted from the projection unit, by detecting a reflection wave from said monitoring area; and

cutting off light radiated toward said projection area or reducing intensity of said light according to an entry state;

setting a first monitoring space including said monitoring area and a passage area through which a detection wave from a front surface of said image projection apparatus to said monitoring area, and a second monitoring space provided on a second monitoring area which is outside of said monitoring area; and

detecting entry into said monitoring area and said second monitoring area severally to perform an alarm process according to an entry state.

15. The image projection method according to claim 14, wherein infrared light or infrared rays are used as said detection wave.

16. The image projection method according to claim 15, further comprising:

monitoring said monitoring area having a width narrower than that of said area projected on said screen by said detection wave source on a basis of image data detected by an image sensor.