US 12,072,671 B2
Holographic projector having a fault detection circuit and method of using same
Timothy Smeeton, Milton Keynes (GB); and Alexander Cole, Milton Keynes (GB)
Assigned to Envisics Ltd, Milton Keynes (GB)
Filed by Envisics Ltd, Milton Keynes (GB)
Filed on Jun. 30, 2021, as Appl. No. 17/364,265.
Claims priority of application No. 2012165 (GB), filed on Aug. 5, 2020.
Prior Publication US 2022/0043394 A1, Feb. 10, 2022
Int. Cl. G03H 1/22 (2006.01); G01S 17/89 (2020.01); G03H 1/08 (2006.01)
CPC G03H 1/2294 (2013.01) [G01S 17/89 (2013.01); G03H 1/0808 (2013.01); G03H 1/2205 (2013.01); G03H 1/2249 (2013.01); G03H 2001/221 (2013.01); G03H 2001/2244 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A holographic projector comprising:
a spatial light modulator arranged to display a hologram of a light pattern for projection and to spatially-modulate light to form a holographic reconstruction, wherein the holographic reconstruction is spatially-separated from the spatial light modulator;
a detector array comprising a plurality of light detection elements arranged to detect light corresponding to a respective plurality of positions of the holographic reconstruction and to provide a respective plurality of output signals related to light detection; and
a fault detection circuit arranged to compare one or more of the plurality of output signals from the respective plurality of light detection elements with one or more of a plurality of expected signals based on the light distribution of the light pattern.