| 摘要 |
PURPOSE: A focusing display apparatus for a projector is provided to display a predetermined graphic according to a focusing operation after performing the focusing of the projector, thereby capable of identifying visually the focusing result and of recognizing the change of focusing. CONSTITUTION: A charge coupled device(103) converts a graphic screen inputted from a focusing lens(101) into an electric signal. An ADC(Analog to Digital Converter)(105) converts the electric signal corresponding to the graphic screen into digitalized information. A DSP(Digital Signal Processor)(107) calculates the focus of the digital information provided by the ADC. A memory(109) is connected to the DSP and stores the calculation information for calculating the focus. A processing circuit(125) generates a luminance signal through a gate circuit on the basis of the focus calculation information. A luminance signal generating circuit(121) outputs a luminance signal corresponding to a control value of the processing circuit. A high pass filter(119) removes the noise relating to the luminance signal. A digital integrator(117) measures variations of the luminance signal. A CPU(Central Processing Unit)(113) calculates a focus level on the basis of the variations of the luminance signal, controls rotation number and direction of a focus driving motor, and provides graphic image information according to the focus levels. An OSD(On Screen Display) control member(111) provides the graphic image information to a screen.
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