Semi-transmission type liquid crystal display which reflects incident light coming from outside to provide a display light source and transmits light from a light source at the back
View Patent ↗A semi-transmission type liquid crystal display that maximizes the luminance in reflection mode and transmission mode. The liquid crystal display comprises a lower substrate with thin film transistors, an opposite substrate facing the lower substrate, a liquid crystal layer between the lower substrate and the opposite substrate, a reflection electrode formed in a reflection area of the lower substrate, a transparent electrode formed in a transparent area of the lower substrate, a common electrode formed on the opposite substrate, and a drive circuit for applying a voltage between the reflection electrode and the transparent electrode and the common electrode. The potential difference between a drive voltage applied to that surface of the lower substrate which contacts the liquid crystal layer and a drive voltage applied to that surface of the opposite substrate which contacts the liquid crystal layer is lower in the reflection area than in the transparent area.
1. A liquid crystal display comprising a lower substrate on which interconnections and thin film transistors are formed;
an opposite substrate so arranged as to face said lower substrate;
a liquid crystal layer sandwiched between said lower substrate and said opposite substrate;
a reflection electrode formed in a reflection area of said lower substrate;
a transparent electrode formed in a transparent area of said lower substrate; and
a common electrode formed on said opposite substrate;
wherein an insulating layer is deposited on said thin film transistors, said reflection electrode and said transparent electrode are formed directly on said insulating layer at predetermined regions, said transparent electrode is electrically connected to a source electrode of each of said thin film transistors via a contact hole formed in said insulating layer, said opposite substrate is electrically connected to said transparent electrode and an insulating film is deposited on that surface of said opposite substrate which contacts said liquid crystal layer, and a drive circuit for applying a voltage between said reflection electrode and said transparent electrode and said common electrode,
whereby a potential difference between a drive voltage applied to that surface of said lower substrate which contacts said liquid crystal layer and a drive voltage applied to that surface of said opposite substrate which contacts said liquid crystal layer is made lower in said reflection area than in said transparent area.
2. The liquid crystal display according to claim 1 , wherein said insulating film is formed of one selected from SiN, SiO 2 , Ti 2 O 3 , Ta 2 O 5 , SiO, Al 2 O 3 , acryl and arton.
3. The liquid crystal display according to claim 2 , wherein said insulating layer is formed of one selected from SiN, SiO 2 , Ti 2 O 3 , Ta 2 O 5 , SiO, Al 2 O 3 , acryl and arton.
4. A liquid crystal display comprising a lower substrate on which interconnections and thin film transistors are formed;
an opposite substrate so arranged as to face said lower substrate;
a liquid crystal layer sandwiched between said lower substrate and said opposite substrate;
a reflection electrode formed in a reflection area of said lower substrate;
a transparent electrode formed in a transparent area of said lower substrate; and
a common electrode formed on said opposite substrate;
wherein a first color filter is formed on said opposite substrate, a second color filter is formed on said thin film transistors and said reflection electrode is formed directly on said second color filter, and a drive circuit for applying a voltage between said reflection electrode and said transparent electrode and said common electrode, whereby a potential difference between a drive voltage applied to that surface of said lower substrate which contacts said liquid crystal layer and a drive voltage applied to that surface of said opposite substrate which contacts said liquid crystal layer is made lower in said reflection area than in said transparent area.