KR101316810B1 - Liquid crystal Lens - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to liquid crystal lenses, and more particularly, to liquid crystal lenses that provide a three-dimensional image representation and a high cell gap retention effect.

 To this end, the present invention, the first substrate; A first electrode formed on the entire inner surface of the first substrate; A second substrate facing the first substrate; A second electrode formed spaced apart from each other by a first distance from the inner surface of the second substrate; An insulating film formed to cover the second electrode; A third electrode overlapping the second electrode on the insulating layer and formed to be spaced apart from each other by a second distance; A liquid crystal layer formed between the first substrate and the second substrate; A liquid crystal lens is formed between the first substrate and the second substrate and includes a column spacer formed in a region overlapping with the third electrode. An end portion of the liquid crystal lens for driving the liquid crystal layer using three electrodes is provided. It is advantageous to provide a refractive index characteristic such as a glass stove through the liquid crystal lens by blocking the with a column spacer. Accordingly, the incident light phase change can be precisely controlled without distortion, thereby enhancing the improvement effect of the 3D image and providing a high cell gap effect, thereby improving the product competitiveness by realizing a high quality liquid crystal lens.

Description

Liquid crystal lens

1A and 1B are a perspective view and a cross-sectional view of a general liquid crystal lens, respectively

FIG. 2 is a graph showing a phase change of incident light when light passes through the liquid crystal lens of FIGS. 1A and 1B.

3 is a cross-sectional view schematically showing the configuration of a liquid crystal lens according to the present invention;

4 is a graph illustrating the refractive index distribution of the liquid crystal lens according to the present invention.

5 is a graph illustrating the refractive index distribution of the liquid crystal lens except for the configuration of the column spacer in the liquid crystal lens according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

110: liquid crystal lens 120: first substrate

122: first electrode 124: first alignment layer

130: second substrate 132: second electrode

134: insulating layer 136: third electrode

138: second alignment film 140: liquid crystal layer

150: column spacer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to liquid crystal lenses, and more particularly, to liquid crystal lenses that provide a three-dimensional image representation and a high cell gap retention effect.

In general, a liquid crystal display device is composed of two opposite electrodes and a liquid crystal layer formed therebetween. The liquid crystal molecules of the liquid crystal layer are driven by an electric field generated by applying a voltage to the two electrodes. The liquid crystal molecules have a polarization property and an optical anisotropy. The polarization property means that when the liquid crystal molecules are placed in the electric field, the charges in the liquid crystal molecules collide with both sides of the liquid crystal molecules, and the molecular alignment direction changes according to the electric field. Refers to changing the path of the emitted light and the polarization state differently depending on the incident direction or polarization state of the incident light due to the elongated structure of the liquid crystal molecules and the aforementioned molecular arrangement direction.

Accordingly, the liquid crystal layer exhibits a difference in transmittance due to the voltage applied to the two electrodes, and the image can be displayed by varying the difference between the pixels.

Recently, a liquid crystal lens has been proposed in which the liquid crystal layer serves as a lens by taking advantage of the properties of such liquid crystal molecules.

That is, the lens is to control the path of the incident light by position using the difference in refractive index between the material constituting the lens and the air, the liquid crystal layer is driven by a different electric field for each position by applying a different voltage to each position to the liquid crystal layer In this case, incident light incident on the liquid crystal layer may sense a different phase change for each position, and as a result, the liquid crystal layer may control the path of the incident light like an actual lens.

Such a liquid crystal lens will be described with reference to the drawings.

1A and 1B are a perspective view and a cross-sectional view of a general liquid crystal lens, respectively.

1A and 1B, a general liquid crystal lens 10 includes a liquid crystal layer 40 (see FIG. 1) formed between first and second substrates 20 and 30 facing each other and a first and a second substrates 20 and 30, ). The first electrode 22 is formed on the entire inner surface of the first substrate 20, and the second electrode 32 spaced apart from each other by a distance d is formed on the outer surface of the second substrate 30.

When a voltage is applied to the first and second electrodes 22 and 32, an electric field E is formed between the two electrodes, and the second electrode 32 is formed on the entire outer surface of the second substrate 30. Since the electric field is separated from each other, the electric field substantially perpendicular to the first and second substrates 20 and 30 is generated in a region far from the separation section 32a of the second electrode 32 without forming a perfect vertical electric field. On the other hand, an inclined electric field is generated in the first and second substrates 20 and 30 in the region close to the separation section 32a of the second electrode 32.

Therefore, the electric field E generated by the first and second electrodes 22 and 32 changes in intensity and direction according to the distance from the separation section 32a of the second electrode 32, and as a result, the electric field E The liquid crystal layer 40 driven by the phase changes the phase of incident light differently according to the distance from the separation section 32a of the first and second electrodes 22 and 32.

FIG. 2 is a graph illustrating a phase change of incident light when light passes through the liquid crystal lens of FIGS. 1A and 1B. FIG. 2 also shows the phase change when light passes through an actual lens for comparison.

In FIG. 2, the first, second, and third curves 40a, 40b, and 40c are curves showing the phase change of light passing through the liquid crystal lens, and the fourth curve 40d is the one that passes through an actual lens made of glass or the like. This curve shows the phase change of light. As can be seen from the first, second and third curves 40a, 40b and 40c, the phase change of the light passing through the liquid crystal lens is different from the phase difference of the second electrode (32 in Figs. 1A and 1B) Symmetrically about the center 32a of FIG.

For example, the first, second, and third curves 40a, 40b, and 40c are curves when the distance (d in FIGS. 1a and 1b) of the second electrode (32 in FIGS. 1a and 1b) is gradually changed. Properly adjusting the separation distance (d in FIGS. 1a and 1b) is limited and thus does not give perfect results as a real lens. That is, the first and second curved lines 40a and 40b have less phase change than the fourth curve 40d as a whole, while the third curve 40c has a larger phase change than the fourth curve 40d as a whole.

This result is due to the low phase change control parameter of the liquid crystal lens, and it is possible to control the phase change in the liquid crystal lens because the separation distance of the second electrode 32 of FIGS. 1A and 1B (see FIGS. 1A and 1B). Only the voltage applied to d) and the second electrode (32 in FIGS. 1A and 1B), and even if properly adjusted, it is difficult to obtain the same curve as the phase change in the actual lens.

Accordingly, the present invention can precisely control the incident light phase change in the liquid crystal layer by driving the liquid crystal layer by using three electrodes, and also improves the improvement effect of the 3D image and provides a high cell gap maintaining effect. It aims to provide.

The present invention to achieve the above object, the first substrate; A first electrode formed on the entire inner surface of the first substrate; A second substrate facing the first substrate; A second electrode formed spaced apart from each other by a first distance from the inner surface of the second substrate; An insulating film formed to cover the second electrode; A third electrode overlapping the second electrode on the insulating layer and formed to be spaced apart from each other by a second distance; A liquid crystal layer formed between the first substrate and the second substrate; A liquid crystal lens is formed between the first substrate and the second substrate and includes a column spacer formed in an area overlapping the third electrode.

The liquid crystal lens may include a first alignment layer formed on the first electrode; The semiconductor device may further include a second alignment layer formed on the third electrode.

The liquid crystal lens further includes a passivation layer formed between the third electrode and the second alignment layer.

The first distance may be smaller than the second distance.

The first electrode is formed on the entire surface of the first substrate.

The liquid crystal layer is formed between the first electrode and the third electrode.

The column spacer is formed of a resin.

The resin is characterized in that the photosensitive organic resin.

The dielectric constant of the column spacer is smaller than the long-term dielectric constant of the liquid crystal molecules contained in the liquid crystal layer and is characterized in that the larger than the uniaxial dielectric constant of the liquid crystal molecules.

The permittivity (ε _{c / s} ) of the column spacer is the formula ε _{c / s} = 1/3 (ε _L + 2 ε _S ), where ε _L is the long-term dielectric constant of the liquid crystal molecules, ε _S is the uniaxial dielectric constant of the liquid crystal molecules It is characterized by appearing as.

The refractive index of the column spacer is characterized in that the same as the uniaxial refractive index of the liquid crystal molecules contained in the liquid crystal layer.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings.

FIG. 3 is a cross-sectional view schematically illustrating the configuration of the liquid crystal lens 110 according to the present invention, and includes first and second substrates 120 and 130, a liquid crystal layer 140, and a column spacer 150.

The first substrate 120 has a first electrode 122 is formed over the entire surface, a first alignment layer 124 is formed on the first electrode 122.

The second substrate 130 is an opposing substrate of the first substrate 120. As shown in FIG. 2, the second electrodes 130 are spaced apart from each other by a first distance d1 at both ends of the lower surface of the second substrate 130. An 132 is formed, and an insulating film 134 is formed on the lower surface of the second electrode 132 and the entire surface of the exposed second substrate 130.

In addition, the third electrode 136 is formed to be spaced apart from the insulating layer 134 by the second distance d2 in the region overlapping the second electrode 132. In this case, the second distance d2 is a distance longer than the first distance d1.

The second electrode 132 and the third electrode 136 may be formed of a transparent conductive material or a metal material such as ITO, in particular, the third electrode 136 is a black matrix (BM) for blocking the transmission of light It is preferable to form a metal material to perform the role.

A second alignment layer 138 is formed under the third electrode 136 and the exposed insulating layer 134, and the first alignment layer 124 and the second alignment layer 138 may be omitted.

In addition, a separate passivation layer may be further formed between the third electrode 136 and the second alignment layer 138.

In addition, the liquid crystal layer 140 and the column spacer 150 are formed between the first substrate 120 and the second substrate 130, that is, between the first alignment layer 124 and the second alignment layer 138.

The column spacer 150 is formed between both ends of the first and second substrates 120 and 130 facing each other, and is preferably formed to overlap the constituent region of the third electrode 130.

The material of the column spacer 150 may be a resin, and in particular, may be formed through a photolithography process using a photosensitive organic resin, and the distance between the first substrate 120 and the second substrate 130 or the The uniformity of the cell gap expressed by the distance between the first alignment layer 124 and the second alignment layer 138 may be improved.

The column spacer 150 prevents light leakage along with the third electrode 130 which also serves as a black matrix, thereby changing the phase of incident light generated through the liquid crystal lens 110, that is, the refractive index n of the liquid crystal lens. Looking at (x) at the II position of the liquid crystal lens 110 is as shown in FIG.

Referring to the graph of FIG. 4, since the light is not transmitted to the portion (between I-II) where the column spacer 150 is formed, there is no refractive index graph and the curvature of the refractive index graph close to the position II is maintained without change. It can be seen that this can be said to be one of the purpose of forming the column spacer 150.

That is, referring to the graph of FIG. 5 together, the refractive index graph of FIG. 5 is a graph showing the refractive index of the liquid crystal lens that does not constitute the column spacer 150 proposed by the present invention. ) Does not represent a refractive index value in the column spacer 150 forming portion, whereas in the liquid crystal lens without the column spacer 150 formed therein, a separate refractive index having an inflection point at which the curvature of the graph changes in the region I-II of FIG. 5 is changed. You can see that the value exists.

This is because, as in the present invention, without forming the column spacer 150, for example, when forming a ball spacer or the like, since the liquid crystals are not isolated, the liquid crystals of adjacent liquid crystal lenses are in contact with each other, resulting in high interfacial energy. It may represent a distorted refractive index, and may actually display a distorted image.

However, when the column spacer 150 is formed at the boundary of the liquid crystal lens as in the present invention, the light passing through the column spacer 150 replacement region (I-II) is transferred to the second electrode 132 and the third electrode ( Although the light exits through the opening of 136 and the refractive index appears, the liquid crystal between adjacent liquid crystal lenses is separated from each other by the column spacer 150, and thus the energy of the interface is so small that the replacement region of the column spacer 150 is actually small. In the position adjacent to I-II), the curvature of the graph appears as a shape having no inflection point.

Therefore, by removing the region having the inflection point where the curvature of the graph is changed as in the region (I-II) of FIG. 5, only the region that provides a neat refractive index value without variation in curvature, such as a glass lens, is removed. By providing high-quality three-dimensional images can be provided.

The column spacer 150 configured for this purpose may have any permittivity within a range in which the permittivity (ε _{c / s} ) of the physical properties does not affect the electric field formed by the first to third electrodes 122, 132, and 136. It is preferable to have a relationship as shown in the following formula (1), more preferably have a value satisfying the formula (2).

Equation (1) ε _{c / s} = ε _S <ε _{c / s} <ε _L

Equation (2) ε _{c / s} = 1/3 (ε _L + 2ε _S )

In Equation (1) (2), ε _{c / s} is the dielectric constant of the column spacer 150, ε _L is the long-term dielectric constant of the liquid crystal molecules, ε _S is the uniaxial dielectric constant of the liquid crystal molecules.

In addition, the refractive index (n _{c / s} ) of the column spacer 150 is also possible if the dielectric constant of the range that does not distort the image, but preferably has a refractive index of the glass (glass), the liquid crystal layer as shown in Equation (3) The uniaxial refractive index level of the liquid crystal molecules configured at 140 may be sufficient.

Equation (3) n _{c / s} = n _S (n _S is the uniaxial refractive index of the liquid crystal molecules)

The liquid crystal lens according to the present invention as described above, by using the three electrodes to block the end of the liquid crystal lens driving the liquid crystal layer with a column spacer to provide the refractive index characteristics of the same type as the glass lens through the liquid crystal lens. It is an advantage. Accordingly, the incident light phase change can be precisely controlled without distortion, thereby improving the 3D image improvement effect and providing a high cell gap retention effect, thereby improving product competitiveness by realizing high quality liquid crystal lens.

Claims (11)

A first substrate; A first electrode formed on the entire inner surface of the first substrate; A second substrate facing the first substrate; A second electrode formed spaced apart from each other by a first distance from the inner surface of the second substrate; An insulating film formed to cover the second electrode; A third electrode overlapping the second electrode on the insulating layer and formed to be spaced apart from each other by a second distance; A liquid crystal layer formed between the first substrate and the second substrate; A column spacer formed between the first substrate and the second substrate and formed in an area overlapping the third electrode; Liquid crystal lens including The method according to claim 1, A first alignment layer formed on the first electrode; A second alignment layer formed on the third electrode Liquid crystal lens further comprising The method according to claim 2, A passivation layer formed between the third electrode and the second alignment layer. Liquid crystal lens further comprising The method according to claim 1, And the first distance is a distance smaller than the second distance. Claim 5 was abandoned upon payment of a set-up fee. The method according to claim 1, The first electrode is formed on the entire surface of the first substrate, the liquid crystal lens Claim 6 has been abandoned due to the setting registration fee. The method according to claim 1, The liquid crystal layer is formed between the first electrode and the third electrode The method according to claim 1, Liquid crystal lens, characterized in that the column spacer is formed of a resin The method of claim 7, wherein The resin is a liquid crystal lens, characterized in that the photosensitive organic resin The method according to claim 1, The dielectric constant of the column spacer is less than the long-term dielectric constant of the liquid crystal molecules contained in the liquid crystal layer and characterized in that the larger than the uniaxial dielectric constant of the liquid crystal molecules. The method according to claim 1, The dielectric constant of the column spacer (ε _{c / s} ), the formula ε _{c / s} = 1/3 (ε _L + 2 ε _S ), where ε _L is the long-term dielectric constant of the liquid crystal molecules, ε _S is the uniaxial dielectric constant of the liquid crystal molecules Liquid crystal lens, characterized in that shown as The method according to claim 1, The refractive index of the column spacer is the same as the uniaxial refractive index of the liquid crystal molecules contained in the liquid crystal layer

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