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US 7,252,388 B2Granted
Projector with tilt-angle detecting capability
AssigneeCasio Computer Co., Ltd.
InventorMasahiro Ogawa
Life of this patent
Estimating the term…
Abstract
A projector includes two range sensors of a phase difference method. The range sensors are laid out near a projection lens in such a way that a line connecting the centers of two photo-sensor arrays incorporated in one of the range sensors crosses a line connecting the centers of two photo-sensor arrays incorporated in the other range sensors approximately at the right angles. A control section controls those range sensors to measure distances to a plurality of ranging points on a screen. The control section computes the tilt angle of the screen based on the measured distances and supplies the computed tilt angle to a trapezoid correcting section and an optical mechanism section.
Claims17
A projector which projects light to form an image on a surface of a screen and has a tilt-angle detecting capability, said projector comprising:
- a projection lens through which the light for forming the image on the screen is projected;
- a focus control section which controls focusing of the projection lens;
- and
- a tilt-angle detecting unit which detects a tilt angle of said surface of said screen with respect to an optical axis of light projected by said projector, said tilt-angle detecting unit comprising:
- a plurality of distance measuring sections, each of which includes at least two light receiving sections and at least two lenses, and which measure distances to a plurality of distance-measuring points on said screen;
- a control section which controls said plurality of distance measuring sections to measure said distances to said plurality of distance-measuring points on said screen;
- and
- a tilt-angle acquiring section which acquires said tilt angle of said surface of said screen with respect to said optical axis of said light projected onto said screen based on at least three measured distances measured by said plurality of distance measuring sections as controlled by the control section;
- wherein each of said distance measuring sections performs distance measuring by detecting a phase difference;
- wherein said plurality of distance measuring sections are laid out adjacent to the projection lens such that respective baselines of the plurality of distance measuring sections are adjacent to a circumference of the projection lens and cross each other, said baselines being lines connecting incidence centers of the associated light receiving sections of the distance measuring sections;
- and
- wherein the focus control section controls the focusing based on at least one of the distances measured by at least one of the distance measuring sections.
9 more elements
A projector which projects light to form an image on a surface of a screen and has a tilt-angle detecting capability, said projector comprising:
- a projection lens through which the light for forming the image on the screen is projected;
- a focus control section which controls focusing of the projection lens;
- and
- a tilt-angle detecting unit which detects a tilt angle of said surface of said screen with respect to an optical axis of light projected by said projector, said tilt-angle detecting unit comprising:
- a distance measuring section which includes at least four light receiving sections and at least four lenses, and which measures distances to a plurality of distance-measuring points on said screen based on a phase difference;
- a control section which controls said distance measuring section to measure said distances to said plurality of distance-measuring points on said screen;
- and
- a tilt-angle acquiring section which acquires said tilt angle of said surface of said screen with respect to said optical axis of said projected light based on at least three measured distances measured said distance measuring section as controlled by the control section;
- wherein the distance measuring section is adjacent to the projection lens, and the light receiving sections are arranged such that at least two lines, each of which connects incidence centers of at least two of the light receiving sections, are adjacent to a circumference of the projection lens and cross one another;
- and
- wherein the focus control section controls the focusing based on at least one of the distances measured by the distance measuring section.
8 more elements
A projector which projects light to form an image on a surface of a screen and has a tilt-angle detecting capability, said projector comprising:
- a projection lens through which the light for forming the image on the screen is projected;
- a focus control section which controls focusing of the projection lens;
- a tilt-angle detecting unit which detects a tilt angle of said surface of said screen with respect to an optical axis of light projected by said projector;
- and
- a correcting section which corrects distortion of a projected image caused by inclination of said screen based on said tilt angle detected by said tilt-angle detecting unit;
- wherein the tilt-angle detecting unit comprises:
- a plurality of distance measuring sections, each of which includes at least two light receiving sections and at least two lenses, and which measure distances to a plurality of distance-measuring points on said screen;
- a control section which controls said plurality of distance measuring sections to measure said distances to said plurality of distance-measuring points on said screen;
- and
- a tilt-angle acquiring section which acquires said tilt angle of said surface of said screen with respect to said optical axis of said light projected onto said screen based on at least three measured distances measured by said plurality of distance measuring sections as controlled by the control section;
- wherein each of said distance measuring sections performs distance measuring by detecting a phase difference;
- and
- wherein said plurality of distance measuring sections are laid out adjacent to the projection lens such that respective baselines of the plurality of distance measuring sections are adjacent to a circumference of the projection lens and cross each other, said baselines being lines connecting incidence centers of the associated light receiving sections of the distance measuring sections;
- and
- wherein the focus control section controls the focusing based on at least one of the distances measured by the distance measuring sections.
12 more elements
Dependencies are inferred from the claim text.