Barco has filed a patent for a hybrid projector architecture that combines steered and unsteered light. The system uses a first projector with a spatial light modulator and a second projector with a light steering module. The light output is split between the two projectors based on luminance levels, with the unsteered light contributing a larger proportion for lower luminance levels. The patent aims to improve image projection systems by optimizing light distribution. GlobalData’s report on Barco gives a 360-degree view of the company including its patenting strategy. Buy the report here.
According to GlobalData’s company profile on Barco, under-screen fingerprint recognition was a key innovation area identified from patents. Barco's grant share as of June 2023 was 1%. Grant share is based on the ratio of number of grants to total number of patents.
Hybrid projector architecture combining steered and unsteered light
A recently filed patent (Publication Number: US20230199156A1) describes an image projection system that utilizes two projectors to project modulated light onto a screen. The first projector includes a spatial light modulator, while the second projector includes a light steering module. A controller processes image data and generates control signals for the spatial light modulator and the light steering modulator. The processing involves splitting the light output between the two projectors in a way that ensures the second modulated light includes a portion of the light for each pixel of the image, while the first modulated light makes up the majority of the light for pixels with target illumination levels below a certain threshold.
The patent also mentions that the controller can generate a modified target image by raising the pixel values of the target image to a power greater than 1. The control signals for the second projector are then based on this modified target image. The splitting of light is performed on a pixel-by-pixel basis according to the target illumination levels. The controller maintains a fixed ratio of luminance between the second modulated light and the first modulated light for pixels with target illumination levels below the threshold. However, for pixels with target illumination levels exceeding the threshold, the controller allows the ratio to exceed the fixed ratio.
The fixed ratio mentioned in the patent is less than 20%. The second projector is capable of achieving a maximum illumination level at least 10 times greater than the first projector. The controller utilizes a lookup table (LUT) to split the light output between the two projectors. The second projector includes a second spatial light modulator, and the controller applies an alignment warping to the image data to drive the second spatial light modulator.
The patent also describes a check performed by the controller to determine the feasibility of displaying the target image. If the check determines that display is not feasible, the controller performs tone mapping on the image data and continues the processing with the tone mapped image data. The first projector utilizes a broadband light source, which uniformly illuminates the spatial light modulator. The second projector, on the other hand, includes a narrowband light source, such as laser diodes. The light steering module includes phase modulators that steer the light emitted by the laser diodes. The controller implements a forward model that computes a predicted light field for the steered light, using separate point spread functions for the different colors emitted by the laser diodes. The forward model can be iterative and accounts for both the steered and unsteered components of light from the light steering module.