An optoelectronic device includes a display, including a first substrate, which is transparent to optical radiation at a given wavelength, and a first array of display cells including pixel circuit elements disposed on the first substrate at a first pitch, with gaps of a predefined size between the pixel circuit elements. An emitter array includes a second substrate, parallel and in proximity to the first substrate, and a second array of emitters, which are disposed on the second substrate at a second pitch that is different from the first pitch, and which are configured to emit optical radiation at the given wavelength toward the first substrate. Control circuitry is configured to identify the emitters that are aligned with the gaps between the pixel circuit elements and to selectively drive the identified emitters to emit the optical radiation through the gaps.