Brightness and colour control of a projection appliance
First Claim
1. A projection apparatus for projecting an image onto a projection screen, comprising an imaging device that can be controlled pixel by pixel and is provided for representing the image at a reduced scale, an illumination unit for illuminating the imaging device, and a projection assembly comprising a projection lens and provided for imaging the image represented by the imaging device enlarged on the projection screen, wherein the illumination unit comprises a dynamic color filter for time-sequential mixing of primary colors, a spatial light mixing system for compensating local differences in brightness distribution, an optical outcoupling element for coupling out a part of the luminous flux generated by the illumination unit for illuminating the imaging device, and a sensor for measuring the intensity of the light coupled out by the optical outcoupling element, wherein the intensity measured by the sensor is a measure for the illumination level of the imaging device, characterized in that the outcoupling element is arranged in the illumination path between the illumination unit and the imaging device, wherein the outcoupling element is arranged between the output of the spatial light mixing system and the imaging device, the outcoupling element couples light out of the light path on its way from the illumination unit to the imaging device, wherein the outcoupling unit couples light out of the light path on its way from the output of the light mixing system to the imaging device, and the projection apparatus comprises a control unit which is used to control the color of the projected image by controlling the imaging device or by controlling the quantity of illumination light in relation to the signal (I) of the sensor.
1 Assignment
0 Petitions
Accused Products
Abstract
In order to control the brightness and/or the color of a projection apparatus (1), more particularly of a rear projection apparatus of a projection wall, wherein the image generation is based on time-sequential mixing of primary colors, it is proposed that a semi-transparent mirror (14) is used to couple out a portion of the light supplied to the imaging device (11), that a sensor (15) is used to measure said light portion and that the image generation is controlled with the signal thus obtained.
73 Citations
27 Claims
-
1. A projection apparatus for projecting an image onto a projection screen, comprising
an imaging device that can be controlled pixel by pixel and is provided for representing the image at a reduced scale, an illumination unit for illuminating the imaging device, and a projection assembly comprising a projection lens and provided for imaging the image represented by the imaging device enlarged on the projection screen, wherein the illumination unit comprises a dynamic color filter for time-sequential mixing of primary colors, a spatial light mixing system for compensating local differences in brightness distribution, an optical outcoupling element for coupling out a part of the luminous flux generated by the illumination unit for illuminating the imaging device, and a sensor for measuring the intensity of the light coupled out by the optical outcoupling element, wherein the intensity measured by the sensor is a measure for the illumination level of the imaging device, characterized in that the outcoupling element is arranged in the illumination path between the illumination unit and the imaging device, wherein the outcoupling element is arranged between the output of the spatial light mixing system and the imaging device, the outcoupling element couples light out of the light path on its way from the illumination unit to the imaging device, wherein the outcoupling unit couples light out of the light path on its way from the output of the light mixing system to the imaging device, and the projection apparatus comprises a control unit which is used to control the color of the projected image by controlling the imaging device or by controlling the quantity of illumination light in relation to the signal (I) of the sensor.
-
26. A method for controlling the color of a projected image of a projection apparatus that is provided for projecting an image onto a projection screen, comprising
an imaging device that can be controlled pixel by pixel and is provided for representing the image at a reduced scale, an illumination unit for illuminating the imaging device, and a projection assembly comprising a projection lens and provided for imaging the image represented by the imaging device enlarged on the projection screen, wherein the illumination unit comprises a dynamic color filter for time-sequential mixing of primary colors, a spatial light mixing system for compensating local differences in brightness distribution, wherein an optical outcoupling element is used for coupling out a part of the luminous flux generated by the illumination unit for illuminating the imaging device, and wherein a sensor a is used for measuring the intensity of the light coupled out by the optical outcoupling element, wherein the intensity measured by the sensor is a measure for the illumination level of the imaging device, characterized in that the outcoupling element couples light for the sensor out of the light path on its way from the illumination unit to the imaging device, wherein the outcoupling element is arranged between the output of the spatial light mixing system and the imaging device, the outcoupling element is used to couple light out of the light path on its way from the light mixing system to the imaging device, wherein the outcoupling unit couples light out of the light path on its way from the output of the light mixing system to the imaging device, and a control unit is used to control the imaging device in a controlled manner and in relation to the signal (I) of the sensor or to control the quantity of illumination light.
Specification
-
- Resources
-
Current AssigneeBarco Control Rooms Gmbh (Barco NV)
-
Original AssigneeBarco Control Rooms Gmbh (Barco NV)
-
InventorsLang, Harald, Dambach, Soren
-
Application NumberUS10/536,835Publication NumberTime in Patent OfficeDaysField of SearchUS Class Current353/84CPC Class CodesH04N 5/74 Projection arrangements for...H04N 9/3114 by using a sequential colou...H04N 9/3182 Colour adjustment, e.g. whi...
