Three dimensional image projector stabilization circuit

• US 9,039,207 B2
• Filed: 11/09/2012
• Issued: 05/26/2015
• Est. Priority Date: 01/25/2012
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: DeCusatis, Casimer M.
• Primary Examiner(s): CHOWDHURY, SULTAN U.
• Application Number:
  US13/672,947
• Publication Number:
  US 20130188157A1
• Time in Patent Office: 928 Days
• Field of Search: 353/20, 353/30, 353/31, 353/122, 353/85, 353/94, 353/99, 348744-747, 348/769, 348/E9.026, 315/368.15, 315/368.18, 315/370, 315/371, 372/29.011, 372/29.015, 372/30
• US Class Current: 353/122
• CPC Class Codes: G03B 21/2073 Polarisers in the lamp house peculiar to electronic spatial light modulators H04N9/3197
• CPC Class Codes: G03B 35/16 by sequential viewing
• CPC Class Codes: G03B 35/26 using polarised or coloured light separating different viewpoint images
• CPC Class Codes: G09G 2310/0286 Details of a shift registers arranged for use in a driving circuit
• CPC Class Codes: H04N 13/337 using polarisation multiplexing
• CPC Class Codes: H04N 13/363 using image projection screens volumetric display H04N13/388
• CPC Class Codes: H04N 9/3129 scanning a light beam on the display screen scanning a light beam on a screen in displays other than projection devices G09G3/02; scanning systems in general G02B26/10; projectors using laser light sources in general H04N9/3161

Abstract

A method for providing a feedback circuit for a three dimensional projector. First and second input devices and a sensor for determining the rotational speed of the second input device are provided. A control device for controlling the rotational speed of the second input device and a phase locked loop (PLL) are provided. A phase reference signal is created based on the signal rate of the first input device. A phase signal is created based on the rotational speed of the second input device. The PLL compares the phase reference signal and the phase feedback signal to determine whether the first input device and the second input device are synchronized. A signal is sent to the control device for the second input device to change the rotational speed of the second input device in response to determining that the first input device and the second input device are not synchronized.

Claims

1. A method comprising:

providing a first input device;

providing a second input device;

providing a sensor for determining a rotational speed of the second input device;

providing a control device for the second input device, the control controlling the rotational speed of the second input device;

providing a phase locked loop (PLL);

creating a phase reference signal based on a signal rate of the first input device;

creating a phase feedback signal based on the rotational speed of the second input device as measured by the sensor;

comparing, by the PLL, the phase reference signal and the phase feedback signal to determine whether the first input device and the second input device are synchronized; and

sending, by the PLL, a signal to the control device for the second input device to change the rotational speed of the second input device responsive to determining that the first input device and the second input device are not synchronized.

2. The method of claim 1, further comprising applying a programmable delay to the phase feedback signal prior to the comparing by the PLL.

3. The method of claim 1, further comprising applying at least one of a signal conditioner and a signal amplifier the phase feedback signal prior to the comparing by the PLL.

4. The method of claim 1, further comprising modifying the phase reference signal prior to the comparing by the PLL.

5. The method of claim 1, wherein the first input device is an imaging device.

6. The method of claim 1, wherein the first input device is a light source.

7. The method of claim 1, wherein the second input device is a rotating polarizing beam splitter (PBS).

8. The method of claim 1, wherein the second input device is a digital mirror device (DMD) comprising rotating mirrors.

9. The method of claim 1, wherein the second input device is an imaging device.

10. The method of claim 1, wherein the sensor is a tachometer.