CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from and the benefit of Korean Patent Application No. 10-2018-0048071, filed on Apr. 25, 2018, which is hereby incorporated by reference for all purposes as if fully set forth herein.

BACKGROUND

Field

Exemplary implementations of the invention relate generally to display devices, and more specifically to display devices having improved optical efficiency.

Discussion of the Background

A liquid crystal display device includes a liquid crystal display panel which includes two opposed substrates and a liquid crystal layer disposed between the substrates. The liquid crystal display device generates an electric field in the liquid crystal layer by applying a voltage to an electric field generating electrode. Accordingly, an alignment direction of liquid crystal molecules of the liquid crystal layer is determined, and polarization of incident light is controlled to display an image. The liquid crystal display device may include a wavelength conversion member to express a color. The wavelength conversion member may include pigment particles including a predetermined color or a light-emitting material configured to emit a predetermined color. In a case in which the wavelength conversion member includes the light-emitting material, optical efficiency may be determined by a light absorption rate of the light-emitting material.

The above information disclosed in this Background section is only for understanding of the background of the inventive concepts, and, therefore, it may contain information that does not constitute prior art.

SUMMARY

Display devices constructed according to exemplary implementations of the invention have improved optical efficiency and color reproducibility.

For example, display devices and driving methods according to the exemplary implementations of the invention are capable of controlling at least two light sources that are time-division driven to improve color reproducibility and luminous efficiency of the display device.

More specifically, according to the principles and exemplary implementations of the invention, a display device has a light source unit to provide a first light and a second light having different peak wavelengths to a wavelength conversion member. The wavelength conversion member includes a light-emitting material that absorbs at least one of the first light and the second light and converts a wavelength of the absorbed light. One pixel area of a plurality of pixel areas of a display panel outputs the first light. A peak wavelength of the first light may be determined by considering color purity of the first light. The second light may have a shorter wavelength than the first light. Thus, light absorption rate and optical conversion efficiency of the light-emitting material with respect to the light provided from the light source unit may be improved. Accordingly, a display device having improved color reproducibility and luminous efficiency is achieved.

Additional features of the inventive concepts will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the inventive concepts.

According to one or more embodiments of the invention, a display device includes: a light source unit having: a first light source to emit first light having a first peak wavelength; and a second light source to emit second light having a second peak wavelength, the second peak wavelength being shorter than the first peak wavelength; a wavelength conversion member to absorb the second light and convert the second light into first color light and second color light, each of the first color light and the second color light having peak wavelengths different from the first peak wavelength and the second peak wavelength; and a display panel having a first pixel area to display the first color light, a second pixel area to display the second color light, and a third pixel area to display the first light, wherein the first peak wavelength and the second peak wavelength have a value of about 365 nm or more to about 500 nm or less.

The first light and the second light may be blue light.

The first peak wavelength may be in a range of about 450 nm or more to about 500 nm or less, and the second peak wavelength may be in a range of about 365 nm or more to less than the first peak wavelength.

The wavelength conversion member may be configured to convert the first light and the second light into the first color light and the second color light, and the third pixel area may be configured to display the first light and the second light.

The display panel may be configured to display an image on a frame-by-frame basis, each frame may include a first sub-frame and a second sub-frame which are separate time divisions of the frame, and wherein the first light source may be configured to emit light during the first sub-frame, and the second light source may be configured to emit light during the second sub-frame.

The third pixel area may be configured to block display of the second light during the second sub-frame.

The first pixel area and the second pixel area may be configured to block display of the first color light and the second color light, respectively, during the first sub-frame.

The first color light and the second color light may have a longer wavelength than the first light, wherein the first color light may have a longer wavelength than the second color light, and wherein the second pixel area may be configured to block display of the second color light during the first sub-frame.

The first light source and the second light source may be configured to emit light during the second sub-frame, and the third pixel area may be configured to block display of the first and the second light during the second sub-frame.

The display panel may be configured to display an image on a frame-by-frame basis, each frame including a first sub-frame, a second sub-frame, and a third sub-frame which are separate time divisions of the frame, wherein the first light source may be configured to emit light during the first sub-frame, and the second light source may be configured to emit light during the second sub-frame and the third sub-frame, and wherein the first pixel area and the second pixel area may be configured to block display of the first color light and the second color light during the first sub-frame, the second pixel area and the third pixel area may be configured to block display of the second color light and the second light during the second sub-frame, and the first pixel area and the third pixel area may be configured to block display of the first color light and the second light during the third sub-frame.

The wavelength conversion member may include a first wavelength conversion portion and a second wavelength conversion portion, wherein the first wavelength conversion portion comprises a first light-emitting material and the second wavelength conversion portion comprises a second light-emitting material, wherein the first wavelength conversion portion may be configured to convert at least one of the first light and the second light into the first color light, the second wavelength conversion portion may be configured to convert at least one of the first light and the second light into the second color light, and wherein the first pixel area may overlap the first wavelength conversion portion, and the second pixel area may overlap the second wavelength conversion portion.

The wavelength conversion member may further include a light-transmitting portion that transmits the first light, and the third pixel area may overlap the light-transmitting portion.

The wavelength conversion member may be disposed under the display panel, and the wavelength conversion member may be configured to provide the first light, the second light, the first color light, and the second color light to the display panel.

According to one or more embodiments of the invention, a display device includes: a display panel having a first pixel area to display first color light, a second pixel area to display second color light, and a third pixel area to display blue light; and a light source unit having a first light source to provides first blue light having a first peak wavelength and a second light source to provide second blue light having a second peak wavelength different from the first peak wavelength, wherein the display panel is configured to display an image on a frame-by-frame basis, each frame including a first sub-frame and a second sub-frame which are separate time division of a frame, and wherein at least one of the first light source and the second light source are configured to emit light in each of the first sub-frame and the second sub-frame, and the third pixel area is configured to block display of the second blue light while the second light source emits light.

In an exemplary embodiment, the first pixel area may include a first wavelength conversion portion, the second pixel area may include a second wavelength conversion portion, and wherein the first wavelength conversion portion may be configured to convert at least one of the first blue light and the second blue light into the first color light, and the second wavelength conversion portion may be configured to convert at least one of the first blue light and the second blue light into the second color light.

The display device may further include a wavelength conversion member disposed under the display panel, wherein at least one of the first blue light and the second blue light may be incident on the wavelength conversion member, wherein the wavelength conversion member may be configured to convert a wavelength of the incident light to form the first color light and the second color light, and wherein the wavelength conversion member may be configured to provide the first color light, the second color light, and the light incident on the wavelength conversion member to the display panel.

The first peak wavelength may be longer than the second peak wavelength, and wherein the blue light to be displayed by the third pixel area may be the first blue light.

The first light source may be configured to emit light during the first sub-frame, and the second light source may be configured to emit light during the second sub-frame.

The first pixel area and the second pixel area may be configured to block display of the first color light and the second color light, respectively, during the first sub-frame.

The first color light and the second color light may have a longer wavelength than the first light, wherein the first color light may have a longer wavelength than the second color light, and wherein the second pixel area may be configured to block display of the second color light during the first sub-frame.

The first light source may be configured to emit light during the first sub-frame, and wherein the first light source and the second light source may be configured to emit light during the second sub-frame.

The first peak wavelength may be in a range of about 440 nm or more to about 500 nm or less, and the second peak wavelength may be in a range of about 365 nm or more to less than the first peak wavelength.

According to one or more embodiments of the invention, a method of time division driving a display device having a first light source, a second light source, and a wavelength conversion member configured to receive light from the first and the second light sources to generate a first color light and a second color light to display an image on a display panel on a frame-by-frame basis, with each frame having first and second sub-frames which are separate time divisions of the frame is provided, the method including: driving the first light source, during a first time period, to generate a first light in the first sub frame; transmitting the first light, during the first time period, to the outside of the display to display the first light on the display panel; driving the second light source, during a second time period after the first time period, to generate a second light in the second sub frame; transmitting the second light, during the second time period, to the wavelength conversion member to generate the first color light and the second color light on the display panel; and blocking the second light, during the second sub frame, from being transmitted to the outside of the display device.

The transmitting of the first light, during the first time period, to the outside of the display device may include transmitting the first light through the wavelength conversion member, and the blocking of the second light, during the second time period, to the outside of the display includes blocking the transmitting of the second light from being transmitted to the wavelength conversion member.

The method may further include: blocking the first light, during the first time period, from generating the first color light and the second color light in the wavelength conversion member.

The method may further include: transmitting the first light, during the first time period, to the wavelength conversion member to generate the first color light.

The method may further include: transmitting the first light, during the first time period, to the wavelength conversion member to generate the second color light.

The method may further include: blocking the first light, during the first time period from generating the second color light in the wavelength conversion member.

The display device may include a liquid crystal layer and blocking light includes aligning liquid crystals in the liquid crystal layer to prevent light from being transmitted therethrough.

Each frame further has a third sub frame, and the method further including: driving one of the first and second light source during a third time period to generate a third light in the third sub frame; transmitting the third light, during the third time period, to the outside of the display device to display the third light on the display panel; and blocking at least one of the first and second light, during the third sub frame, from being transmitted to the outside of the display device.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

