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US 7,604,356 B2Granted
Projection type image display apparatus and lighting circuit control method
AssigneeKabushiki Kaisha Toshiba
InventorYoshio Kubo
Life of this patent
Estimating the term…
Abstract
One color segment is selected from among a plurality of color segments. A lamp lighting circuit is controlled so that a lamp pulse is superimposed on a DC lamp current during a time period during which a light projected from a lamp transmits through the selected color segment.
Claims14
A projection-type image display apparatus comprising:
- a rotatable color wheel which includes a plurality of color filters transmitting light of different frequencies from each other;
- a discharge lamp which generates a light transmitting through the color wheel;
- a lamp lighting circuit which supplies a DC lamp current to the discharge lamp to generate the light;
- an image projection section which reflects the light transmitting through the color wheel toward a projection lens based on an input image signal to project an image;
- a display mode selection section which selects a display mode of the image projected onto the screen;
- and
- a controller which controls the lamp lighting circuit so that a lamp pulse of a predetermined width and height is superimposed on the DC lamp current during a time period during which a light projected from the discharge lamp transmits through a specified one of the color filters of the rotatable color wheel in accordance with the display mode selected by means of the selection section,
- wherein, when the display mode is switched by the display mode selection section from a normal display mode to another display mode, which differs from the normal display mode at least in image color balance, a current waveform supplied to the discharge lamp is set to prevent a load on the discharge lamp from being greater than that in the normal display mode.
5 more elements
A method for controlling a lamp lighting circuit of a projection-type image display apparatus, including a lamp lighting circuit which supplies a DC lamp current to the discharge lamp to light the discharge lamp, the method comprising:
- selecting a display mode of an image projected onto a screen;
- and
- controlling the lamp lighting circuit so that a lamp pulse of a predetermined width and height is superimposed on the DC lamp current during a time period during which a light projected from the discharge lamp transmits through a specified one of the color filters of the rotatable color wheel in accordance with the selected display mode,
- wherein, when the display mode is switched from a normal display mode to another display mode, which differs from the normal display mode at least in image color balance, a current waveform supplied to the discharge lamp is set to prevent a load on the discharge lamp from being greater than that in the normal display mode.
1 more element
Dependencies are inferred from the claim text.