The JBD full-color Micro prototype has been shipped, but is it actually a stacked structure?

On August 28, JBD (Shanghai Xianyao Display Technology Co., Ltd.) announced that its single-chip RGB Micro LED screen Phoenix series prototype had been shipped. The previously released and currently in mass production Hummingbird is targeted for 30-degree FOV applications, while the Phoenix series is designed for FOV waveguides above 50-degree.

Phoenix's current engineering samples use a 0.22-inch panel with a resolution of 2K and a subpixel pitch of 2.5um. A 2X2 subpixel array is combined in a 5-um pitch white pixel with 4 independent current drive channels. Three of the channels are connected to AlInGaN blue emitters, AlInGaN green emitters and AlInGaP red emitters respectively.

It is worth noting that these semiconductor emitters arevertically stacked and coaxially arranged, as shown in the following figure. This unique emitter arrangement allows for high WPE and highly concentrated light emission in the vertical direction. In the future production stage, JBD will launch a0.3-inch panel as a standard product with a 2 micron subpixel pitch and a 4K resolution, which is equivalent to a 2K resolution of 4 micron white pixel pitch.

Figure 1. (a)Completed multicolor wafers,(b) 45-degree tilted SEM images of a 5 um color pixel pitch array, and (c) multi-layer interconnection technology, focused ion beam cutting and cross-section SEM images of electrical connections are not shown schedule.

To date, using quantum dots (QDs) for color conversion remains the most common method to implement a single RGB screen. However, there are still problems to be solved. For example, as the pump flux density and Micro LED junction temperature increase, the QD lifetime will be significantly reduced.

Alternative epitaxial technologies that integrate three colors, such as polychromatic epitaxial layers, selective area epitaxy, regrowth, nanostructures and 3D structures, have not yet produced convincing prototypes at < 10 um pixel spacing. Most of existing full-color Micro LED screens are achieved by combining three independent monochromatic red, green and blue panels with an X-cube prism.

There are more current cases of single-sided single-chip RGB screens because it can realize light engines in two shape and size.

In addition, since simplified system-level integration on AR glasses reduces optical losses, higher waveguide collimation efficiency can be achieved. However, due to the technical challenges of integrating three colors onto a single wafer, Micro LED-based ultra-small pitch (< 5 um) full-color monolithic panels for AR applications are still difficult to achieve.

JBD's Phoenix prototype demonstrates the feasibility of using a monolithic RGB microled screen with a native semiconductor pitch of 5 microns, which improves brightness by more than 2 orders of magnitude compared to existing single-sided MicroOLED screens. Because simplified system-level integration on AR glasses reduces optical losses, higher waveguide collimation efficiency can be achieved.

A key feature of the technology is thetotal stack thickness of less than 5 microns, the thinnest thickness ever produced, minimizing absorption losses within the cavity.

Coupled with the ability to operate natural light sources at high flux density, white balance brightness of up to 1 million nits can be achieved using this platform. Another distinctive feature of full-native color solutions is the ability to achieve a narrow full-width at half maximum (FWHM) spectrum, resulting in high color quality and color purity images.

It is reported that JBD will showcase prototypes of native color single-chip multicolor projectors at various industry events in the first half of 2024. These panels are scheduled to be mass produced in 2025.