Projector

Details Projector Projector

1999-03-26

2001-07-17

Dowling, William (Department: 2851)

Optics: image projectors

Pointer

C353S122000

Reexamination Certificate

active

06260973

ABSTRACT:

This application is based on Japanese Patent Application No. HEI 10-81963, the content of which is hereby incorporated by reference.
FIELD OF THE INVENTION
The present invention relates to a projector for projecting an image on a screen. In one aspect, the present invention relates to a projector capable of detecting light, emitted from outside the projector, at a predetermined position on a screen.
BACKGROUND OF THE INVENTION
A projector provided with charge-coupled devices (CCD) within an optical system has been proposed. When a position is indicated on a screen using a laser pointer during the projection of an image on the screen, the laser light is reflected by the screen, travels in a direction opposite to that of the projected light, and enters the optical system of the projector. In such projectors, the CCD detects the laser light so that the indicated position on the screen can be determined.
For example, a window area, having items such as screen frame forward, frame back, etc., can be displayed along with an internet page or an image photographed with a digital camera. When a desired item is specified by the laser pointer, the specified position on the screen is detected by the projector, and a corresponding frame forward or frame back operation is performed. Further, not only can detecting a specified position trigger an operation, it is also possible to fetch an image corresponding to an area specified by the laser pointer.
When using an area CCD as a photosensing means in a conventional projector, the detection area of the reflected light extends over the entire screen, and extensive data processing is required for detection when an area CCD is used. Furthermore, an area CCD is expensive an adds an unnecessary cost to the device.
The laser pointers conventionally used for indicating a position on a screen illuminate the screen with the laser light. Since laser light is harmful when it enters the human eye, extreme care must be taken by anyone using a laser pointer so that the laser light does not stray off the screen inadvertently.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a projector capable of detecting only the light reflected from within a predetermined area on a screen.
Another object of the present invention is to provide a projector capable of specifying a position without using laser light and detecting the specified position.
According to one aspect, the present invention attains these objects by providing a projector having a photosensing means for detecting light entering the optical system from outside the optical system, wherein the photosensing means is capable of detecting only the light reflected from within a predetermined area on the screen.
According to another aspect, the projector of the present invention includes a linear CCD as a photosensing means resulting in a long, thin area on a screen being detectable by the photosensing means.
According to a further aspect, the projector of the present invention projects an image on a screen, and has a pointing image display means for displaying a pointing image on a screen which specifies a position within the image, photosensing means for detecting the specified position, and spectral means for separating the image light received from the pointing image display means into spectral components so as to direct the spectral components to the photosensing means.
These and other objects, advantages and features of the invention will become apparent from the following description thereof taken in conjunction with the accompanying drawings, which illustrate specific embodiments of the invention.


REFERENCES:
patent: 5235363 (1993-08-01), Vogeley et al.
patent: 5422693 (1995-06-01), Vogeley et al.
patent: 5572251 (1996-11-01), Ogawa
patent: 5738429 (1998-04-01), Tagawa et al.
patent: 5883476 (1999-03-01), Noguchi et al.
patent: 5898465 (1999-04-01), Kawashima et al.
patent: 8-320921 (1996-12-01), None
patent: 8-331667 (1996-12-01), None
patent: 9-80372 (1997-03-01), None
patent: 10-40006 (1998-02-01), None

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