Abstract: Provided are an optical device, a display device including the optical device, and an electronic device including the display device. According to one or more embodiments of the present disclosure, there is provided an optical device including a substrate, a first metalens layer disposed on a surface of the substrate and including a plurality of first nanostructures, and a second metalens layer disposed on the surface of the substrate, overlapping with the first metalens layer in a thickness direction of the substrate, and including a plurality of second nanostructures. The first metalens layer may include a first refractive portion where the plurality of first nanostructures is disposed to refract incident light, and a first non-refractive portion where the plurality of first nanostructures is not disposed. The plurality of second nanostructures may overlap with the first refractive portion and the first non-refractive portion in the thickness direction of the substrate.

Abstract: A display device includes: a plurality of display areas; and a first transmissive area between the plurality of display areas and configured to transmit light traveling from outside, wherein each of the plurality of display areas includes: a first sub-display area comprising first sub-pixels configured to emit first light; a second sub-display area comprising second sub-pixels configured to emit second light; a third sub-display area comprising third sub-pixels configured to emit third light; and a fourth sub-display area comprising fourth sub-pixels configured to emit fourth light.

Abstract: A holographic display is provided. A holographic display includes, a first substrate, a first lens layer on one surface of the first substrate, a light source layer on an opposite surface of the first substrate, a second substrate on the first lens layer, a light modulation element on one surface of the second substrate, and a second lens layer on an opposite surface of the second substrate, wherein each of the first lens layer and the second lens layer includes a meta-lens.

Abstract: The present invention provides a smart mirror apparatus using an LCD panel. The smart mirror of the present invention includes a reflective mirror, which is provided in the vehicle, and an LCD panel, which is placed in a light path between the reflective mirror and eyes of the driver and has one or two polarizing sheets. The smart mirror further includes an incident light detecting unit, which detects both the brightness of the incident light transmitted from the rear to the LCD panel and the brightness around the LCD panel, and calculates a difference value therebetween. The smart mirror further includes a voltage determination unit, which receives the calculated difference value and determines the drive voltage depending on the difference value, and a voltage apply and supply unit which applies the drive voltage, determined by the voltage determination unit, to the LCD panel.

Abstract: A back bias voltage level detector is capable of accurately detecting a back bias voltage level by constantly maintaining a voltage inputted into a comparator using a clamp circuit or a current mirror circuit. The back bias voltage level detector includes voltage control circuitry for accurately detecting the back bias voltage and maintaining a constant input voltage to the comparator, and first and second resistors coupled in series between an electric voltage and a back bias voltage for distributing voltage inputted thereto. A comparator compares the distributed and inputted voltage with a reference voltage. A back bias voltage detector is provided for outputting a detection signal by determining that a predetermined back bias voltage is detected when the input voltage and the reference voltage are identical as a result of the comparison.