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SCANNING TYPE IMAGE DISPLAY APPARATUS

  • US 20120169752A1
  • Filed: 12/28/2011
  • Published: 07/05/2012
  • Est. Priority Date: 04/28/2010
  • Status: Active Grant
First Claim
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1. A scanning type image display apparatus, comprising:

  • a light source portion which emits a laser beam;

    a frame buffer which temporarily stores, frame by frame, a plurality of pixel data inputted from outside and representing an image to be displayed on a display screen;

    a scanning mirror which scans the laser beam two-dimensionally in a first direction and in a second direction intersecting the first direction to project the laser beam to the display screen;

    a drive controller which outputs a drive signal to the scanning mirror to control the scanning mirror; and

    a display controller which reads out the pixel data from the frame buffer, generates display data for modulating an intensity of the laser beam using the readout pixel data, and causes the light source portion to emit an intensity-modulated laser beam based on the display data, whereinthe frame buffer has a two-dimensional logical address space configured corresponding to the display screen, and stores the plurality of pixel data in address positions of the two-dimensional logical address space corresponding to respective positions on the display screen in an order in which the plurality of pixel data is inputted,in the two-dimensional logical address space of the frame buffer, a direction corresponding to the order in which the pixel data is stored is defined as an address direction,the drive controller drives the scanning mirror so that the laser beam is scanned in a direction nonparallel to a direction corresponding to the address direction on the display screen, and outputs, to the display controller, information relating to the drive signal to be outputted to the scanning mirror,the display controller calculates a scanning position of the laser beam on the display screen by the scanning mirror based on the information relating to the drive signal inputted from the drive controller, reads out a plurality of pixel data including pixel data stored in an address position of the two-dimensional logical address space corresponding to the calculated scanning position on the display screen or a position near the scanning position by executing a burst access to the frame buffer in the address direction, and implements interpolation using the plurality of readout pixel data to generate the display data corresponding to the scanning position of the laser beam on the display screen,the scanning mirror is a resonant mirror, and driving frequencies in the first direction and in the second direction are respectively set near resonant frequencies of the scanning mirror in the first direction and in the second direction,the drive controller outputs, to the scanning mirror, the drive signal configured such that the driving frequency is discretely set with an interval of a predetermined step size, andthe drive controller switches, in a case where the resonant frequency of the scanning mirror in one of the first direction and the second direction varies, the driving frequency to a driving frequency at a succeeding step, before the varied resonant frequency reaches the discretely set driving frequency at the succeeding step, and switches, in response to the switching of the driving frequency, the driving frequency of the scanning mirror in the other of the first direction and the second direction while maintaining a predetermined relationship.

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