TWI658305B - Liquid crystal lens and 2d/3d switchable display device applying the same - Google Patents

Abstract

Liquid crystal lens and display device capable of switching 2D / 3D using the same. The liquid crystal lens includes a first substrate, a second substrate, a liquid crystal layer, and a plurality of electrode groups. The second substrate is disposed opposite the first substrate. The liquid crystal layer is disposed between the first substrate and the second substrate. Each electrode group includes a first electrode pair and a second electrode. The first electrode pair is disposed between the first substrate and the liquid crystal layer. The first electrodes are spaced apart in a first direction. The second electrode is disposed between the second substrate and the liquid crystal layer. The projection position of the first electrode pair in a vertical substrate direction is between the projections of the opposite electrode sides of the second electrode and does not overlap with the electrode sides. Both the first electrode pair and the second electrode extend along a second direction. The second direction is different from the first direction.

Description

Liquid crystal lens and display device capable of switching 2D / 3D using the same

The invention relates to a liquid crystal lens and a switchable 2D / 3D display device using the same.

A liquid crystal lens is a lens with a graded refractive index made of a liquid crystal material. Since the axial distribution of the liquid crystal can be changed by applying different voltages, thereby achieving a zoom effect, a liquid crystal lens has been applied in a stereo display in recent years as a switching device for two-dimensional and three-dimensional images.

According to an embodiment of the present invention, a liquid crystal lens is provided. The liquid crystal lens includes a first substrate, a second substrate, a liquid crystal layer, and a plurality of electrode groups. The second substrate is disposed opposite the first substrate. The liquid crystal layer is disposed between the first substrate and the second substrate. Each electrode group includes a first electrode pair and a second electrode. The first electrode pair is disposed between the first substrate and the liquid crystal layer. The first electrodes are spaced apart in a first direction. The second electrode is disposed between the second substrate and the liquid crystal layer. The projection of the first electrode pair in the direction of a vertical substrate is between the projections of the opposite two electrode sides of the second electrode, and does not overlap with those electrode sides Stacked. Both the first electrode pair and the second electrode extend along a second direction. The second direction is different from the first direction.

According to an embodiment of the present invention, a 2D / 3D switchable display device is provided. The 2D / 3D switchable display device includes a display panel and a liquid crystal lens. The liquid crystal lens includes a first substrate, a second substrate, a liquid crystal layer, and a plurality of electrode groups. The second substrate is disposed opposite the first substrate. The liquid crystal layer is disposed between the first substrate and the second substrate. Each electrode group includes a first electrode pair and a second electrode. The first electrode pair is disposed between the first substrate and the liquid crystal layer. The first electrodes are spaced apart in a first direction. The second electrode is disposed between the second substrate and the liquid crystal layer. The projection of the first electrode pair in the direction of a vertical substrate is between the projections of the opposite two electrode sides of the second electrode and does not overlap with the electrode sides. Both the first electrode pair and the second electrode extend along a second direction. The second direction is different from the first direction. The liquid crystal lens is disposed on the display panel.

In order to have a better understanding of the above and other aspects of the present invention, the following specific examples are described in detail below in conjunction with the accompanying drawings:

102, 202‧‧‧ LCD lens

104, 204‧‧‧phase delay curve

106‧‧‧First substrate

108‧‧‧second substrate

110‧‧‧first alignment layer

112‧‧‧Second alignment layer

114‧‧‧LCD layer

116‧‧‧LCD gap

118‧‧‧ overlapping area

320‧‧‧ display device

322‧‧‧Display Panel

324‧‧‧lens element

326‧‧‧ imaging surface

C‧‧‧ Centerline

D‧‧‧Lens unit pitch

D1‧‧‧ first direction

D2‧‧‧ Second direction

D3‧‧‧Vertical substrate direction

CE1‧‧‧First electrode pair

CE3‧‧‧Third electrode pair

CE4‧‧‧Fourth electrode pair

E1‧‧‧First electrode

E2‧‧‧Second electrode

E3‧‧‧Third electrode

E4‧‧‧ Fourth electrode

ET1, ET2, ET3 ‧‧‧ electrode group

ES1, ES2‧‧‧ electrode side

d‧‧‧height

V1‧‧‧ the first voltage

V2‧‧‧Second voltage

V3‧‧‧Third voltage

V4‧‧‧ Fourth voltage

W1‧‧‧First electrode size

W2‧‧‧Second electrode size

W3‧‧‧Third electrode size

W4‧‧‧ Fourth electrode size

FIG. 1 is a cross-sectional view of a liquid crystal lens according to an embodiment.

FIG. 2 is a partial perspective view of the liquid crystal lens of FIG. 1.

FIG. 3 is a partial cross-sectional view of the liquid crystal lens of FIG. 1.

FIG. 4 is a cross-sectional view of a liquid crystal lens of a comparative example.

FIG. 5 is a schematic diagram of a 2D / 3D switchable display device according to an embodiment.

Please refer to Figure 1 to Figure 3. FIG. 1 is a cross-sectional view of a liquid crystal lens 102 according to an embodiment. 2 and 3 are a partially enlarged perspective view and a cross-sectional view, respectively, of the imaginary frame portion of the liquid crystal lens 102 of FIG. 1, and FIG. 3 further shows a phase retardation curve 104 of the liquid crystal. The liquid crystal lens 102 includes a first substrate 106, a second substrate 108, and a plurality of electrode groups (for example, an electrode group ET1 shown in FIG. 1, an electrode group ET2 and an electrode group ET3 on both sides of the electrode group ET1, respectively). (Figures 2 and 3 show only the electrode group ET1). The first substrate 106 and the second substrate 108 may be transparent substrates, and materials may include glass, plastic, acrylic, quartz, sapphire, or other suitable hard or flexible materials. In the embodiment, each electrode group includes a first electrode pair CE1, a second electrode E2, a third electrode pair CE3, and a fourth electrode pair CE4, and the materials used may include, for example, indium tin oxide (ITO), indium zinc oxide (IZO) ), Zinc alumina (AZO), indium alumina (AIO), indium oxide (InO), gallium oxide (GaO), indium gallium zinc oxide (IGZO), nano carbon tubes, nano silver, etc. Conductive material.

The two first electrodes E1 of the first electrode pair CE1 and the two third electrodes E3 of the third electrode pair CE3 are spaced apart from each other on the first substrate 106 in the first direction D1, and along a direction different from the first direction D1. The second direction D2 extends. For example, the first direction D1 may be substantially perpendicular to the second direction D2. The two third electrodes E3 of the third electrode pair CE3 are respectively located on opposite outer sides of the first electrode pair CE1. The first alignment layer 110 may be disposed on the first substrate 106, the first electrode pair CE1, and the third electrode pair CE3. In the embodiment, the third electrode E3 of two adjacent electrode groups Connected. For example, referring to FIG. 1, the electrode group ET1 is connected to the third electrode E3 of the electrode group ET2, and the electrode group ET1 is connected to the third electrode E3 of the electrode group ET3.

The two fourth electrodes E4 of the second electrode E2 and the fourth electrode pair CE4 are spaced apart from each other in the first direction D1 on the second substrate 108 and extend along the second direction D2. The two fourth electrodes E4 of the fourth electrode pair CE4 are located on opposite outer sides of the second electrode E2, respectively. The second alignment layer 112 may be disposed on the second substrate 108, the second electrode E2, and the fourth electrode pair CE4. The material of the first alignment layer 110 and the second alignment layer 112 may include a suitable material such as polyimide.

The liquid crystal layer 114 is disposed in a liquid crystal gap 116 between the first substrate 106 and the second substrate 108 which are oppositely disposed. For example, the liquid crystal gap 116 may be defined by a distance between the first alignment layer 110 and the second alignment layer 112 opposite to each other. In one embodiment, the height d of the liquid crystal gap 116 may be 10 μm to 30 μm, preferably 15 μm to 25 μm, but is not limited thereto.

Referring to FIG. 3, in the embodiment, in the electrode group ET1, two first electrodes E1 of the first electrode pair CE1, two third electrodes E3 of the third electrode pair CE3, and two fourth electrodes of the fourth electrode pair CE4. E4 is arranged symmetrically with respect to the center line C of the second electrode E2 in the vertical substrate direction D3. In the vertical substrate direction D3, the projection position of the first electrode pair CE1 on the first substrate 106 is between the projections of the opposite electrode sides ES1 and ES2 of the second electrode E2 and does not overlap the electrode sides ES1 and ES2. The two third electrodes E3 of the third electrode pair CE3 overlap with the electrode sides ES1 and ES2 of the second electrode E2 in the vertical substrate direction D3, respectively. The third electrode E3 and the second electrode E2 have an overlap region 118 having an area larger than 0. For example, the size of the overlapping region 118 is 4 μm to 8 μm, such as 6 μm, but is not limited thereto. to In the vertical substrate direction D3, two third electrodes E3 of the third electrode pair CE3 and two fourth electrodes E4 of the fourth electrode pair CE4 overlap each other. The vertical substrate direction D3 (or the third direction) is different from the first direction D1 and the second direction D2. For example, the vertical substrate direction D3 may be substantially perpendicular to the first direction D1 and the second direction D2.

Referring to FIG. 3, in the embodiment, two first electrodes E1 of the first electrode pair CE1 may have the same first electrode size W1 in the first direction D1. The second electrode E2 may have a second electrode size W2 in the first direction D1. In the embodiment, W1 <W2. For example, W2 * 0.1 W1 W2 * 0.25, such as W1 = W2 * 0.1, or W1 = W2 * 0.15, or W1 = W2 * 0.2, or W1 = W2 * 0.25 In addition, two third electrodes E3 of the third electrode pair CE3 may have the same third electrode size W3 in the first direction D1. The two fourth electrodes E4 of the fourth electrode pair CE4 may have the same fourth electrode size W4 in the first direction D1. For example, W1 <W3, W4 <W3. In one embodiment, the lens unit pitch (Lens Pitch) of the liquid crystal lens 102 is LP, LP <W2, and LP> W1, and LP> W4, but is not limited thereto.

In the embodiment, the display device can use the electrode voltage operation of the liquid crystal lens 102 to achieve a switchable 2D / 3D mode. In one embodiment, the two first electrodes E1 of the first electrode pair CE1 have the same first voltage V1. The second electrode E2 has a second voltage V2. Two third electrodes E3 of the third electrode pair CE3 have the same third voltage V3. The two fourth electrodes E4 of the fourth electrode pair CE4 have the same fourth voltage V4. In one embodiment, in the 3D mode, V3 <V4 <V1 <V2. And it can be V4 = V2-V1, for example. The third voltage V3 may be grounded. In another embodiment, in the 2D mode, V1 = V2 = V3 = V4, such as 0 volts, such as ground or floating.

FIG. 4 shows a cross-sectional view of an electrode group of a liquid crystal lens 202 of a comparative example, which is mainly different from the liquid crystal lens 102 of the embodiment in that the first electrode pair of the embodiment having two first electrodes E1 is CE1 is replaced by a single first electrode E1 disposed between two third electrodes E3. Generally, the height d of the liquid crystal gap 116 is about 30 μm. If the height d of the liquid crystal gap 116 is reduced, for example, the height d is changed from 20 μm, the short response time of the liquid crystal lens 202 can be reduced and the focal length can be increased. However, when the height d of the liquid crystal gap 116 is 20 μm and the liquid crystal lens 202 is operated at the same voltage (for example, the first voltage V1 of the first electrode E1 is 2.4V, and the second voltage V2 of the second electrode E2 is 3.8V, the first (The third voltage V3 of the three electrodes E3 is 0V and the fourth voltage V4 of the fourth electrode E4 is 1.4V). However, it is found that the distribution of the parabola of the phase delay curve 204 of the comparative example liquid crystal near the apex becomes smoother, that is, The apex curvature of the parabola of the delay curve becomes smaller, which will cause the focusing effect of the liquid crystal lens 202 to become worse.

In the case of the same voltage operation and the same height d of the liquid crystal gap 116, the parabola of the liquid crystal phase delay curve 104 of the liquid crystal lens 102 of FIGS. 1 to 3 has more vertices than the liquid crystal lens 202 of FIG. Big curvature. In an embodiment, the height d of the liquid crystal gap 116 of the liquid crystal lens 202 of the comparative example and the liquid crystal lens 102 of the embodiment is 20 μm, and under the same voltage operation (for example, V1 = 2.4V, V2 = 3.8V, V3 = 0V, V4 = 1.4V), the liquid crystal lens 102 of the embodiment can have a better focusing effect on penetrating light. Therefore, the liquid crystal lens 102 of the embodiment can not only shorten the response time and increase the focal length by narrowing the liquid crystal gap 116, but also can produce a better focusing effect.

Please refer to FIG. 5, which illustrates a schematic diagram of a switchable 2D / 3D display device 320 according to an embodiment concept. In an embodiment, the display device 320 may be applied to a virtual reality. (VR) wearable display, but it is not limited to this, and can also be applied to other kinds of display devices that can switch 2D / 3D. The display device 320 includes a display panel 322, a lens element 324, and a liquid crystal lens 102 as shown in FIGS. 1 to 3. The liquid crystal lens 102 is disposed between the image display surface of the display panel 322 and the lens element 324. In one embodiment, the display panel 322 may include, but is not limited to, a liquid crystal display panel 322, and other display panels for displaying 2D images, such as an organic light emitting display panel, may also be used. For example, after the image display light of the display device 320 strikes the first substrate 106 of the liquid crystal lens 102 and passes through the second substrate 108, it passes through the lens element 324 to the imaging plane 326 (such as a pupil plane). 2D / 3D imaging images can be switched by voltage operation of the electrodes of the liquid crystal lens 102.

In summary, although the present invention has been disclosed as above with the embodiments, it is not intended to limit the present invention. Those with ordinary knowledge in the technical field to which the present invention pertains can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope of the attached patent application.

Claims (15)

A liquid crystal lens includes: a first substrate; a second substrate disposed opposite to the first substrate; a liquid crystal layer disposed between the first substrate and the second substrate; and a plurality of electrode groups, each electrode The group includes: a first electrode pair disposed between the first substrate and the liquid crystal layer, the first electrode disposed to be spaced apart in a first direction; and a second electrode disposed between the second substrate and the liquid crystal layer. Between the liquid crystal layers, where the projection of the first electrode pair in a vertical substrate direction is between the projections of the two electrodes on opposite sides of the second electrode and does not overlap with the sides of the electrodes, the first electrode The two first electrode pairs are symmetrically disposed with respect to a center line of the second electrode, wherein the first electrode pair and the second electrode both extend in a second direction, and the second direction and the first direction different. The liquid crystal lens according to item 1 of the scope of patent application, wherein the two first electrodes of the first electrode pair have the same first electrode size W1 in the first direction. The liquid crystal lens according to item 2 of the scope of patent application, wherein the second electrode has a second electrode size W2 in the first direction, and W1 W2 * 0.25. The liquid crystal lens according to item 3 of the scope of patent application, in which W2 * 0.1 W1 W2 * 0.25. The liquid crystal lens according to item 1 of the scope of patent application, wherein the first electrode pair has a first voltage V1, the second electrode has a second voltage V2, and V1 <V2. The liquid crystal lens according to item 1 of the scope of patent application, wherein each electrode group further includes a third electrode pair, which is disposed between the first substrate and the liquid crystal layer, and is respectively located along the first electrode pair. On the two opposite sides of the first direction, the first electrode pair has a first voltage V1, the third electrode pair has a third voltage V3, and V3 <V1. The liquid crystal lens according to item 1 of the scope of patent application, wherein each electrode group further includes a third electrode pair, which is disposed between the first substrate and the liquid crystal layer, and is respectively located along the first electrode pair. The two opposite outer sides of the first direction, wherein the two third electrodes of the third electrode pair and the opposite two electrode sides of the second electrode overlap each other in the vertical substrate direction. The liquid crystal lens according to item 7 of the scope of the patent application, wherein the third electrodes of two adjacent electrode groups are connected. The liquid crystal lens according to item 7 of the scope of patent application, wherein each electrode group further includes a fourth electrode pair, which is disposed between the second substrate and the liquid crystal layer, and is respectively located along the second electrode along the second electrode. The two opposite outer sides in the first direction, wherein the third electrode pair and the fourth electrode pair overlap each other in the direction of the vertical substrate. The liquid crystal lens according to item 1 of the scope of patent application, wherein each electrode group further includes a fourth electrode pair, which is disposed between the second substrate and the liquid crystal layer, and is respectively located along the second electrode along the second electrode. The two opposite sides of the first direction, wherein the second electrode has a second voltage V2, the fourth electrode pair has a fourth voltage V4, and V4 <V2. The liquid crystal lens according to item 1 of the scope of patent application, wherein each electrode group further comprises: a third electrode pair, which is disposed between the first substrate and the liquid crystal layer, and is respectively located on the first electrode pair. Two opposite outer sides along the first direction; and a fourth electrode pair disposed between the second substrate and the liquid crystal layer and respectively located on opposite outer sides of the second electrode along the first direction, wherein the The first electrode pair, the third electrode pair, and the fourth electrode pair are symmetrically disposed with respect to a center line of the second electrode. The liquid crystal lens according to item 11 of the scope of patent application, wherein the first electrode pair has a first voltage V1, the second electrode has a second voltage V2, and the third electrode pair has a third voltage V3. The fourth electrode pair has a fourth voltage V4, and V3 <V4 <V1 <V2. The liquid crystal lens according to item 11 of the scope of the patent application, wherein the liquid crystal layer is disposed in a liquid crystal gap between the first substrate and the second substrate, and a height of the liquid crystal gap is 10 μm to 30 μm. A switchable 2D / 3D display device includes: a display panel; and the liquid crystal lens according to any one of claims 1 to 13 of the scope of patent application, the liquid crystal lens is disposed on the display panel. The switchable 2D / 3D display device according to item 14 of the scope of patent application, further includes a lens element, wherein the liquid crystal lens is located between the lens element and the display panel.