405-nm DLP Transparent Display Reference Design

The design turns car windows into displays using light and film. It can show messages, signs, or info for rides, people, and other vehicles.

The DLP3034-Q1 electronics reference design from Texas Instruments (TI) powers a DLP projector that illuminates a phosphor film embedded in glass to create a transparent window display. Under normal lighting, the phosphor film remains clear, but when exposed to 405-nm light from the DLP3034-Q1 projector, it transforms into a colorful display. This technology enables transparent window displays that support a range of applications, including vehicle-to-vehicle and vehicle-to-pedestrian communication, robo-taxis, ride hailing, advertisements, driver greetings, and car diagnostics.

The reference design features key components including the DLP3034-Q1 0.3” WVGA 405-nm automotive digital micromirror device (DMD), the DLPC120-Q1 DMD controller, a current-controlled LED driver that supports one or two channels, and the required power supplies. These components work together to drive a projector that incorporates a 405-nm LED, optical elements to guide the LED light to the DLP3034-Q1 DMD, and a projection lens that directs the light onto a vehicle window. The system is intended to be used with a transparent phosphor film embedded within the glass. When the film is exposed to 405-nm light from the projector, it emits visible light, turning the clear window into a dynamic display. A full-color display can be achieved using multiple LEDs and phosphor films, each tuned to a specific excitation wavelength.

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The projector and film setup enables a range of display applications within the automotive space. As the industry shifts toward autonomous vehicles, robo-taxis, and ride-sharing, vehicles must be able to communicate externally without compromising the original purpose of the windows. Transparent window displays powered by this reference design provide a way to support vehicle-to-vehicle and vehicle-to-pedestrian communication, display ride-hailing or robo-taxi status, show advertisements, and deliver driver greetings or diagnostics—all while maintaining the clear appearance of the window when not in use.

The automotive DMD is optimized for light sources centered around the 405-nm wavelength, but it may also support other wavelengths. The reference design is configured to drive one or two LEDs, and switching between the two setups only requires adding or removing three specific resistors. While the reference design supports up to two LED channels, the DLP3034-Q1 and DLPC120-Q1 chipset itself is capable of driving up to three channels, offering flexibility for expanded configurations if needed.

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This reference design consists of two boards: the Controller board and the DMD board. They should be connected using a 50-pin flat flex cable, making sure the cable is properly aligned and the clamps on both connectors are securely closed.

Once the boards are connected, attach the power cable to the designated connector and connect the LEDs. In a complete projector setup, ensure that the DMD and LEDs are properly aligned with the optical system. 

TI has tested this reference design. It comes with a bill of materials (BOM), schematics, assembly drawing, printed circuit board (PCB) layout, and more. The company’s website has additional data about the reference design. To read more about this reference design, click here.