TWI416169B - Switchable fresnel lens - Google Patents

Abstract

A switchable Fresnel lens allowing a polarized light passing through is provided. The switchable Fresnel lens includes a Fresnel lens part and an optical material layer. The Fresnel lens part has a light incident surface and a light emergence surface. The Fresnel lens part has birefringence. The polarized light enters the Fresnel lens part from the light incident surface and leaves the Fresnel lens part through the light emergence surface. The refractive index of the Fresnel lens part with respect to the polarized light is capable of being adjusted via an electric field. The optical material layer is disposed on the light emergence surface of the Fresnel lens part, and the optical material layer has a fixed refractive index nx.

Description

Adjustable variable Fresnel lens

The present invention relates to a Fresnel lens, and more particularly to a variable-switchable Fresnel lens.

Fresnel lens, also known as threaded lens, retains the curved surface and curvature of the traditional lens, and uses the differential principle to produce a thin lens that is equivalent to a traditional thick glass lens, so it can save lens material and make it in production. Large lenses can be used to win in size.

Fresnel lenses were first used in lighthouses and are currently used in display devices. In general, in the display field, the Fresnel lens can be used to magnify the display screen of the screen, especially when applied to a large panel which is made up of a plurality of panels, and the optical modification effect through the Fresnel lens. It is possible to make the joint gap between the panels less noticeable to the human eye. However, the use of Fresnel lenses can degrade the quality of the display and limit the viewing angle of the display. Therefore, whether or not to use a Fresnel lens to achieve a specific optical effect is one of the choices that designers often face.

The present invention provides an adjustable variable Fresnel lens that can be deactivated depending on demand.

The present invention provides an adjustable variable Fresnel lens adapted to pass a polarized light. The variable variable Fresnel lens includes a Fresnel lens portion and an optical material layer. The Fresnel lens portion has a light incident surface and a light exit surface. The Fresnel lens portion has birefringence. The polarized light enters the Fresnel lens portion from the light incident surface and exits the Fresnel lens portion from the light exit surface. The refractive index of the Fresnel lens portion for polarized light is adapted to be modulated by an electric field. The layer of optical material is disposed on the light exit surface of the Fresnel lens portion, wherein the layer of optical material has a single refractive index n _x .

In an embodiment of the invention, the material of the Fresnel lens portion comprises a birefringent liquid crystal.

In an embodiment of the invention, the birefringent liquid crystal comprises a positive liquid crystal. The positive-type liquid crystal has a long-axis refractive index n _e and a short-axis refractive index n _o , and the long-axis refractive index n _{e is} larger than the short-axis refractive index n _o . For example, the short-axis refractive index n _o < single refractive index n _x < long-axis refractive index n _{e described above} .

In an embodiment of the invention, the single refractive index n _x is substantially equal to the short-axis refractive index n _o or the long-axis refractive index n _e .

In an embodiment of the invention, the birefringent liquid crystal comprises a negative liquid crystal. The negative liquid crystal has a long-axis refractive index n _e and a short-axis refractive index n _o , and the long-axis refractive index n _{e is} smaller than the short-axis refractive index n _o .

In an embodiment of the invention, the long-axis refractive index n _e < single refractive index n _x < short-axis refractive index n _o . For example, the single refractive index n _x described above is substantially equal to the short-axis refractive index n _o or the long-axis refractive index n _e .

In an embodiment of the invention, the adjustable variable Fresnel lens further includes a two-electrode layer. The Fresnel lens portion and the optical material layer are disposed between the two electrodes, and the refractive index of the Fresnel lens portion for the polarized light is adapted to be modulated by the electric field provided by the two electrode layers.

In an embodiment of the invention, the optical material layer has a connection The surface and a top surface. The joint surface is joined to the light exit surface of the Fresnel lens portion, and the top surface is a flat surface.

In addition to this, the present invention proposes another adjustable variable Fresnel lens adapted to pass a light. The variable variable Fresnel lens includes an adjustable variable polarization unit, a Fresnel lens portion, and an optical material layer. The variably variable polarization unit is adapted to convert light into a polarized light, wherein the variably variable polarization unit determines the polarization direction of the polarized light. The Fresnel lens portion has a light incident surface and a light exit surface, wherein the Fresnel lens portion has birefringence. The polarized light enters the Fresnel lens portion from the light incident surface and exits the Fresnel lens portion from the light exit surface. The variably variable polarization unit is adapted to provide polarized light of different polarization directions such that the Fresnel lens portion changes the refractive index of the polarized light. The layer of optical material is disposed on the light exit surface of the Fresnel lens portion, wherein the layer of optical material has a single refractive index n _x .

In an embodiment of the invention, the variably variable polarization unit comprises a liquid crystal cell.

Based on the above, since the variably variable Fresnel lens can change the refractive index of the Fresnel lens portion to the polarized light through an electric field or a variable polarization unit, it can be determined according to design requirements. The Fresnel lens is turned on.

The above described features and advantages of the present invention will be more apparent from the following description.

[First Embodiment]

1A and FIG. 1B illustrate an adjustable variant of the first embodiment of the present invention. Schematic diagram of a switchable Fresnel lens and a display panel. 1A and 1B are schematic cross-sectional views of a variable-varying Fresnel lens before and after an applied electric field, respectively. Referring to FIG. 1A, the variable-varying Fresnel lens 100 of the present embodiment is adapted to allow a polarized light (for example, polarized light L1), and the Fresnel lens 100 includes a Fresnel lens part. 110 and an optical material layer 120. In the present embodiment, the polarized light L1 is, for example, polarized light that passes through the display panel 200, and the display panel 200 is, for example, a liquid crystal display panel.

As shown in FIG. 1A, the Fresnel lens portion 110 has a light incident surface S1 and a light exit surface S2. In addition to this, the Fresnel lens portion 110 has birefringence, and the polarized light L1 enters the Fresnel lens portion 110 from the light incident surface S1 and exits the Fresnel lens portion 110 from the light exit surface S2. In the present embodiment, the material of the Fresnel lens portion 110 is the birefringent liquid crystal 112.

FIG. 1C is an enlarged schematic view of a birefringent liquid crystal. As shown in FIG. 1C, the birefringent liquid crystals 112 respectively have a long axis d1 and a short axis d2. When light passes through the birefringent liquid crystal 112 and its polarization direction is parallel to the long axis d1, the refractive index of the birefringent liquid crystal 112 defines the light. It is a long-axis refractive index n _e , and when light passes through the birefringent liquid crystal 112 and its polarization direction is parallel to the minor axis d2, the refractive index of the birefringent liquid crystal 112 to light is defined as a short-axis refractive index n _o . In the present embodiment, the birefringent liquid crystal 112 is, for example, a positive type liquid crystal, that is, in FIG. 1A, the long-axis refractive index n _{e of the} birefringent liquid crystal 112 is larger than the short-axis refractive index n _o . Therefore, when an electric field is applied to the birefringent liquid crystal 112 (positive liquid crystal), the long axis d1 of the birefringent liquid crystal 112 is parallel to the direction of the electric field as shown in FIG. 1B.

Referring to FIG. 1A, the optical material layer 120 is disposed on the light exit surface S2 of the Fresnel lens portion 110, and the optical material layer 120 has a single refractive index n _x . Further, in the present embodiment, the refractive index n _x is substantially equal to the short-axis refractive index n _{o of the} birefringent liquid crystal 112. In addition, as shown in FIG. 1A, the optical material layer 120 has a bonding surface S3 and a top surface S4. The joint surface S3 is joined to the light exit surface S2 of the Fresnel lens portion 110, and the top surface S4 is, for example, a flat surface. In the present embodiment, the optical material layer 120 is formed by, for example, a stamper using a stamper, and the Fresnel lens portion 110 is injected, for example, by injecting the birefringent liquid crystal 112. Formed in the irregular cavity formed by the joint surface S3.

In addition, the adjustable variable Fresnel lens 100 of the present embodiment further includes a two-electrode layer 130. In this embodiment, the material of the two-electrode layer 130 is, for example, Indium Tin Oxide (ITO), Indium Zinc Oxide (IZO), or other light-transmitting conductive material. As shown in FIG. 1A, the Fresnel lens portion 110 and the optical material layer 120 are disposed between the two electrodes 130, and the refractive index of the Fresnel lens portion 110 for the polarized light L1 is adapted to be transmitted through the second electrode layer 130. The electric field is modulated.

For example, referring to FIG. 1A, when the electric field between the two electrode layers 130 is not applied between the two electrode layers 130 such that the electric field between the two electrode layers 130 is equal to 0 (ie, E=0), the double in the Fresnel lens portion 110 The major axis direction d1 (shown in FIG. 1C) of the refractive liquid crystal 112 (for example, a positive liquid crystal) is a direction perpendicular to the paper surface and is parallel to the polarization direction of the polarized light L1. In other words, the short-axis direction d2 of the birefringent liquid crystal 112 is perpendicular to the polarization direction of the polarized light L1, so when the polarized light L1 passes through the birefringent liquid crystal 112, the equivalent refractive index of the birefringent liquid crystal 112 is a long-axis refractive index. n _e . When the polarized light L1 exits from the light exiting surface S2 of the Fresnel lens portion 110 and enters the optical material layer 120, since the refractive index of the optical material layer 120 of the present embodiment is n _o , it is different from the Fresnel lens portion 110 Since the equivalent refractive index n _e (for the polarized light L1), the polarized light L1 is refracted at the interface between the Fresnel lens portion 110 and the optical material layer 120. In other words, in the present embodiment, when the electric field between the two electrode layers 130 is equal to 0, the adjustable variable Fresnel lens 100 is in an on state, and the adjustable variable Fresnel lens 100 at this time has Similar to the function of a conventional lens (convex lens, concave lens). In the present embodiment, the adjustable variable Fresnel lens 100 in an open state can enlarge the image frame of the display panel 200. In this way, when a plurality of small-sized display panels 200 need to be combined into a single large panel, the display image of the display panel 200 can be enlarged by opening the adjustable variable Fresnel lens 100, thereby The joint gap is less noticeable by the human eye.

FIG. 1B is a schematic cross-sectional view of a variable-varying Fresnel lens after an electric field is applied. As shown in FIG. 1B, when a voltage is applied to the two-electrode layer 130 to generate an electric field E between the two electrode layers 130, the long-axis direction d1 of the birefringent liquid crystal 112 (for example, a positive-type liquid crystal) of the Fresnel lens portion 110 is as shown. It will be parallel to the direction of the electric field E and perpendicular to the polarization direction of the polarized light L1. In other words, the short-axis direction d2 of the birefringent liquid crystal 112 is parallel to the polarization traveling direction of the polarized light L1, so when the polarized light L1 passes through the birefringent liquid crystal 112, the equivalent refractive index of the birefringent liquid crystal 112 is short-axis refraction. Rate n _o . When the polarized light L1 exits from the light exiting surface S2 of the Fresnel lens portion 110 and enters the optical material layer 120, since the refractive index of the optical material layer 120 of the present embodiment is n _o , it is the same as the polarized light L1 in the Fresnel. The refractive index n _o seen in the lens portion 110 is such that the polarized light L1 does not refract the interface between the Fresnel lens portion 110 and the optical material layer 120, but directly penetrates the Fresnel lens portion 110 and the optical Material layer 120. In other words, in the present embodiment, when the two-electrode layer 130 provides an electric field to the variably variable Fresnel lens 100, the variably variable Fresnel lens 100 is in a closed state, so that the image picture is not affected.

It should be noted that in the present embodiment, the birefringent liquid crystal 112 is a positive liquid crystal and the single refractive index n _{x of the} optical material layer 120 is substantially the same as the short-axis refractive index n _{o of the} birefringent liquid crystal 112. However, in other embodiments, the single refractive index n _x may also be between the short-axis refractive index n _o and the long-axis refractive index n _e , that is, the short-axis refractive index n _o <single refractive index n _x long The axial refractive index n _e . In this case, the designer can also adjust the electric field size according to the single refractive index n _x , thereby modulating the refractive index of the Fresnel lens portion 110 with respect to the polarized light L1. In this way, the Fresnel lens 100 can also be turned on or off by using the change of the electric field. Since the applied principle is the same as the foregoing example, it will not be described here.

On the other hand, in other embodiments, the birefringent liquid crystal 112 may also be a negative liquid crystal in which the long-axis refractive index n _{e of the} negative liquid crystal is smaller than the short-axis refractive index n _o . In other words, when an electric field is applied to both ends of the negative liquid crystal, the short axis d2 of the negative liquid crystal (shown in FIG. 1C) is aligned in the direction of the electric field to form a state as shown in FIG. 1A. That is, the negative axis d1 direction of the negative liquid crystal is parallel to the polarization direction of the polarized light L1 when an electric field is applied, so the equivalent refractive index of the negative liquid crystal is the long-axis refractive index n _e . It can be seen that when the birefringent liquid crystal 112 in the Fresnel lens portion 110 is a negative liquid crystal, and the two electrode layer 130 provides an electric field to the Fresnel lens portion 110, the adjustable variable Fresnel lens 100 is at Open state.

In contrast, when no electric field is applied to both ends of the negative liquid crystal, the short axis d2 of the negative liquid crystal is perpendicular to the direction of the paper surface as shown in FIG. 1B. That is, the short axis d2 direction of the negative liquid crystal is the same as the polarization direction of the polarized light L1 when no electric field is applied, so the equivalent refractive index of the negative liquid crystal is the short axis refractive index n _o . It can be seen that when the birefringent liquid crystal 112 in the Fresnel lens portion 110 is a negative liquid crystal, and the two electrode layer 130 does not provide an electric field to the Fresnel lens portion 110, the variable variable Fresnel lens 100 is at The status of the shutdown.

In other embodiments, the birefringent liquid crystal 112 may also be a negative liquid crystal, and the single refractive index n _x of the optical material layer 120 is between the long-axis refractive index n _e and the short-axis refractive index n _o , that is, The long-axis refractive index n _e < single refractive index n _x < short-axis refractive index n _o . In this case, the designer can also adjust the electric field size according to the single refractive index n _x , thereby modulating the refractive index of the Fresnel lens portion 110 with respect to the polarized light L1. In this way, the Fresnel lens 100 can also be turned on or off by using the change of the electric field. Since the applied principle is the same as the foregoing example, it will not be described here.

[Second embodiment]

2A and FIG. 2B are schematic cross-sectional views showing a variable-variable Fresnel lens and a display panel according to a second embodiment of the present invention, wherein FIGS. 2A and 2B are respectively an adjustable variable Fresnel lens applied with an electric field. Schematic diagram of the profile before and after. Referring to FIG. 2A, the adjustable variable Fresnel lens 300 of the present embodiment is similar to the variable-variable Fresnel lens 100 of FIG. 1A, but the main difference is that the variable-variable Fresnel lens The optical material layer 320 of 300 has a single refractive index n _x substantially equal to the long-axis refractive index n _{e of the} birefringent liquid crystal 312.

In the present embodiment, the birefringent liquid crystal 312 is, for example, a positive liquid crystal, that is, in FIG. 2A, the long-axis refractive index n _{e of the} birefringent liquid crystal 312 is larger than the short-axis refractive index n _o . Therefore, when an electric field is applied to the birefringent liquid crystal 312, the long axis d1 of the positive liquid crystal 312 is parallel to the direction of the electric field as shown in FIG. 2B.

In detail, referring to FIG. 2A, when the electric field between the two electrode layers 130 is not applied between the two electrode layers 130 such that the electric field between the two electrode layers 130 is equal to 0 (ie, E=0), the birefringence in the Fresnel lens portion 310 The long-axis direction d1 of the liquid crystal 312 (for example, a positive-type liquid crystal) is parallel to the polarization direction of the polarized light L1. Therefore, when the polarized light L1 passes through the birefringent liquid crystal 312, the equivalent refractive index of the birefringent liquid crystal 312 is a long axis. Refractive index n _e . Since the equivalent refractive index of birefringence of liquid crystal 312 n _e and the refractive index optical material layer 320 is the same as n _e, so that the polarized light L1 does not occur in the interface refraction Fresnel lens portion 310 and the optical layer 320 material. That is, in the present embodiment, when the electric field between the two electrode layers 130 is equal to 0, the variable-variation Fresnel lens 300 is in a closed state, so that the image picture is not affected.

2B is a schematic cross-sectional view of the variable-variable Fresnel lens after an electric field is applied. As shown in FIG. 2B, when a voltage is applied to the two-electrode layer 130 to generate an electric field E between the two electrode layers 130, the long-axis direction d1 of the birefringent liquid crystal 312 (for example, a positive-type liquid crystal) of the Fresnel lens portion 310 is as shown. It will be parallel to the direction of the electric field E and perpendicular to the polarization direction of the polarized light L1. In other words, the short-axis direction d2 of the birefringent liquid crystal 312 is parallel to the polarization direction of the polarized light L1, so when the polarized light L1 passes through the birefringent liquid crystal 312, the equivalent refractive index of the birefringent liquid crystal 312 is short-axis refraction. Rate n _o . Since the refractive index n _{e of the} optical material layer 320 and the equivalent refractive index of the birefringent liquid crystal 312 are different from the short-axis refractive index n _o , the polarized light L1 may occur at the interface between the Fresnel lens portion 310 and the optical material layer 320. Refraction phenomenon. That is, in the present embodiment, when the two-electrode layer 130 supplies an electric field to the variable-varying Fresnel lens 300, the variable-variable Fresnel lens 300 is in an open state.

It should be noted that in the present embodiment, the birefringent liquid crystal 312 is a positive liquid crystal and the single refractive index n _{x of the} optical material layer 320 is substantially the same as the long-axis refractive index n _{e of the} birefringent liquid crystal 312. However, in other embodiments, the single refractive index n _x may also be between the short-axis refractive index n _o and the long-axis refractive index n _e , that is, the short-axis refractive index n _o <single refractive index n _x long The axial refractive index n _e . In this case, the designer can also adjust the electric field size according to the single refractive index n _x , thereby modulating the refractive index of the Fresnel lens portion 310 with respect to the polarized light L1. In this way, the Fresnel lens 300 can also be switched by the electric field. Since the applied principle is the same as the above example, it will not be described here.

In addition, in this embodiment, although the birefringent liquid crystal 312 is a positive liquid crystal, in other embodiments, the birefringent liquid crystal 312 may also be a negative liquid crystal, wherein the long axis refraction of the negative liquid crystal The rate n _{e is} smaller than the short-axis refractive index n _o . In other words, when an electric field is applied to both ends of the negative liquid crystal, the short axis d2 of the negative liquid crystal is parallel to the direction of the electric field as shown in Fig. 2A. That is, the long axis d1 of the negative liquid crystal is parallel to the polarization direction of the polarized light L1 when an electric field is applied, so the equivalent refractive index of the negative liquid crystal is the long-axis refractive index n _e . It can be seen that when the birefringent liquid crystal 312 in the Fresnel lens portion 110 is a negative liquid crystal, and the two electrode layer 130 provides an electric field to the Fresnel lens portion 310, the adjustable variable Fresnel lens 300 is Disabled.

In contrast, when no electric field is applied to both ends of the negative liquid crystal, the short axis d2 of the negative liquid crystal is perpendicular to the direction of the paper as shown in FIG. 2B. That is, the short axis d2 direction of the negative liquid crystal is parallel to the polarization direction of the polarized light L1 without applying an electric field. Therefore, when the polarized light L1 passes through the negative liquid crystal, the equivalent refractive index of the negative liquid crystal is the short-axis refractive index n _o . It can be seen that when the birefringent liquid crystal 312 in the Fresnel lens portion 110 is a negative liquid crystal, and the two electrode layer 130 does not provide an electric field to the Fresnel lens portion 310, the adjustable variable Fresnel lens 300 is Open state.

On the other hand, in other embodiments, the birefringent liquid crystal 312 may also be a negative liquid crystal and the single refractive index n _{x of the} optical material layer 320 is, for example, between the long-axis refractive index n _e and the short-axis refractive index n _o . between. That is, the long-axis refractive index n _e < single refractive index n _x < short-axis refractive index n _o . In this case, the designer can also adjust the electric field size according to the single refractive index n _x , thereby modulating the refractive index of the Fresnel lens portion 310 with respect to the polarized light L1. In this way, the Fresnel lens 300 can also be turned on or off by using the change of the electric field. Since the applied principle is the same as the foregoing example, it will not be described here.

[Third embodiment]

3A and FIG. 3B are schematic cross-sectional views showing a variable-variable Fresnel lens and a display panel according to a third embodiment of the present invention, wherein FIG. 3A and FIG. 3B respectively show whether an adjustable variable Fresnel lens applies an electric field. Schematic diagram of the section. Referring to FIG. 3A, the adjustable variable Fresnel lens 400 of the present embodiment is adapted to pass a light L2, and the adjustable variable Fresnel lens 400 includes a variable polarization unit 410 and a Fresnel lens. Portion 420 and optical material layer 430. In the present embodiment, the light ray L2 is, for example, light passing through the display panel 500, and the display panel 500 is, for example, a liquid crystal display panel.

As shown in FIG. 3A, the variable-variation polarization unit 410 is adapted to convert the light L2 into a polarized light L3. The variable-variation polarization unit 410 determines the polarization direction of the polarized light L3, wherein the polarization direction of the polarized light L3 is, for example, a direction perpendicular to the paper surface or a direction parallel to the paper surface. In addition, the Fresnel lens portion 420 has a light incident surface S1 and a light exit surface S2. In addition to this, the Fresnel lens portion 420 has birefringence, and the polarized light L3 enters the Fresnel lens portion 420 from the light incident surface S1 and exits the Fresnel lens portion 420 from the light exit surface S2.

In the present embodiment, the material of the Fresnel lens portion 420 includes a birefringent liquid crystal 422, wherein the birefringent liquid crystal 422 is, for example, a positive liquid crystal or a negative liquid crystal. That is, in FIG. 3A, the long-axis refractive index n _{e of the} birefringent liquid crystal 412 is larger or smaller than the short-axis refractive index n _o . In addition, as shown in FIGS. 3A and 3B, the direction of the major axis d1 of the birefringent liquid crystal 412 of the present embodiment is fixed in a direction perpendicular to the polarization direction of the polarized light L3, and the arrangement of the birefringent liquid crystal 412 is arranged. It is fixed.

Referring to FIG. 3A, the optical material layer 430 is disposed on the light exit surface S2 of the Fresnel lens portion 420, and the optical material layer 420 has a single refractive index n _x . Further, in the present embodiment, the single refractive index n _x is substantially equal to the short-axis refractive index n _{o of the} birefringent liquid crystal 422. In addition, as shown in FIG. 3A, the optical material layer 430 has a bonding surface S3 and a top surface S4. The joint surface S3 is joined to the light exit surface S2 of the Fresnel lens portion 420, and the top surface S4 is, for example, a flat surface. In the present embodiment, the optical material layer 430 is formed by, for example, a stamper using a stamper, and the Fresnel lens portion 420 is injected, for example, by injecting the birefringent liquid crystal 422. Formed in the irregular cavity formed by the joint surface S3.

In addition, the variable polarization unit 410 of the present embodiment includes a liquid crystal cell 412. In addition, the two electrode layers 230 are also disposed on opposite surfaces of the liquid crystal cells 412, respectively. The material of the electrode layer 230 is, for example, a light-transmitting conductive material such as Indium Tin Oxide (ITO) or Indium Zinc Oxide (IZO). As shown in FIG. 3A, the variable-variation polarization unit 410 is adapted to provide polarized light L3 of different polarization directions such that the Fresnel lens portion 420 changes the refractive index of the polarized light L3.

For example, referring to FIG. 3A, when a voltage is applied to the two-electrode layer 230 such that the electric field provided by the two-electrode layer 230 is applied to the variable-polarization unit 410, the birefringent liquid crystal 412a in the liquid crystal cell 412 (for example, The long axis d1 of the positive liquid crystal is arranged in the direction of the electric field (that is, the direction parallel to the paper surface), so the polarization direction of the polarized light L3 is the same as the polarization direction of the light L2, and does not change. For example, when the polarization direction of the light ray L2 is the direction perpendicular to the paper surface, the polarization direction of the polarized light L3 passing through the variable polarization unit 410 is also the direction of the vertical paper surface. As a result, when the polarized light L3 enters the Fresnel lens portion 420, the equivalent refractive index of the birefringent liquid crystal 422 is the short-axis refractive index n _o . Since the refractive index n _{o of the} optical material layer 430 and the equivalent refractive index n _{o of the} birefringent liquid crystal 422 are the same, the polarized light L3 does not refract in the interface between the Fresnel lens portion 420 and the optical material layer 430, and It is directly penetrating the Fresnel lens portion 420 and the optical material layer 430. In other words, in the present embodiment, when the electric field provided by the two electrode layer 230 is applied to the variable polarization unit 410, the variable-variable Fresnel lens 400 is in a closed state, so that the image frame is not affected.

FIG. 3B is a schematic cross-sectional view of the variable-variable Fresnel lens when no electric field is applied. As shown in FIG. 3B, when no bias is applied between the two electrode layers 230 such that the electric field between the two electrode layers 230 is equal to 0 (ie, E=0), the birefringent liquid crystal 412a in the liquid crystal cell 412 changes. The polarization direction of the light L2. For example, when the polarization direction of the light ray L2 is the direction perpendicular to the paper surface, the polarization direction of the polarized light L3 passing through the variable polarization unit 410 is parallel to the direction of the paper surface. As a result, when the polarized light L3 enters the Fresnel lens portion 420, the equivalent refractive index of the birefringent liquid crystal 422 is the long-axis refractive index n _e . Since the refractive index n _{o of the} optical material layer 430 and the equivalent refractive index n _{e of the} birefringent liquid crystal 422 are different, the polarized light L3 is refracted at the interface between the Fresnel lens portion 420 and the optical material layer 430. In other words, in the present embodiment, when the two-electrode layer 230 provides an electric field to the variable-variation polarization unit 410, the adjustable variable Fresnel lens 400 is in an open state, and the adjustable variable Fresnel at this time The ear lens 400 has a function similar to a conventional lens (a convex lens, a concave lens).

In the present embodiment, the adjustable variable Fresnel lens 400 in an open state can enlarge the image frame of the display panel 500. In this way, when a plurality of small-sized display panels 500 need to be combined into a single large panel, the adjustable variable Fresnel lens 400 can be opened to enlarge the displayed image, thereby making the joint gap between the panels less. Will be perceived by the human eye.

It is worth mentioning that in the present embodiment, the birefringent liquid crystal 422 is, for example, a positive liquid crystal, and the single refractive index n _{x of the} optical material layer 430 is substantially the same as the long-axis refractive index n _{e of the} birefringent liquid crystal 422. However, in other embodiments, the single refractive index n _x may also be between the short-axis refractive index n _o and the long-axis refractive index n _e , that is, the short-axis refractive index n _o <single refractive index n _x long The axial refractive index n _e .

In addition, in other embodiments, the birefringent liquid crystal 422 may also be a negative liquid crystal, wherein the negative-axis liquid crystal has a long-axis refractive index n _e smaller than the short-axis refractive index n _o . In addition, the single refractive index n _{x of the} optical material layer 430 is, for example, between the long-axis refractive index n _e and the short-axis refractive index n _o , that is, the long-axis refractive index n _e <single refractive index n _x < short-axis refraction Rate n _o . Under the above circumstances, the designer can also design the arrangement of the birefringent liquid crystal 422 in the Fresnel lens portion 420 according to the single refractive index n _x and provide polarization of different polarization directions by the variable polarization unit 410. Light is caused to cause the Fresnel lens portion 420 to change the refractive index of the polarized light L1. In this way, the Fresnel lens 400 can also be turned on or off by using the change of the electric field. Since the applied principle is the same as the foregoing example, it will not be described here.

In addition, although the birefringent liquid crystal 412a of the present embodiment changes the polarization direction of the light ray L2 without applying an electric field, in other embodiments, the birefringence liquid crystal 422a may also have an applied electric field. The polarization direction of the light ray L2 is changed.

Fourth Embodiment

4A and FIG. 4B are cross-sectional views showing a variable-variable Fresnel lens and a display panel according to a fourth embodiment of the present invention, wherein FIG. 4A and FIG. 4B respectively show whether an adjustable variable Fresnel lens applies an electric field. Schematic diagram of the section. Referring to FIG. 4A, the adjustable variable Fresnel lens 600 of the present embodiment is similar to the adjustable variable Fresnel lens 400 of FIG. 3A, but the main difference is that the variable-variable Fresnel lens The optical material layer 630 of 600 has a single refractive index n _x substantially equal to the long-axis refractive index n _{e of the} birefringent liquid crystal 622.

As shown in FIG. 4A, the variable-variation polarization unit 610 is adapted to provide polarized light L3 of different polarization directions such that the Fresnel lens portion 620 changes the refractive index of the polarized light L3. For example, referring to FIG. 4A, when a voltage is applied to the two-electrode layer 230 to generate an electric field E between the two electrode layers 230, the long axis of the birefringent liquid crystal 612a (for example, a positive liquid crystal) in the liquid crystal cell 612. It will be arranged in the direction of the electric field (that is, in the direction parallel to the paper surface), so the polarization direction of the polarized light L3 is the same as the polarization direction of the light ray L2, and does not change. As a result, when the polarized light L3 enters the Fresnel lens portion 620, the equivalent refractive index of the birefringent liquid crystal 622 is the short-axis refractive index n _o . Since the refractive index n _{e of the} optical material layer 630 and the equivalent refractive index n _{o of the} birefringent liquid crystal 622 are different, the polarized light L3 is refracted at the interface between the Fresnel lens portion 620 and the optical material layer 630. That is, in the present embodiment, when the two-electrode layer 230 supplies an electric field to the variable-variation polarization unit 610, the variable-variation Fresnel lens 600 is in an on state.

4B is a schematic cross-sectional view of a variable-varying Fresnel lens prior to application of an electric field. As shown in FIG. 4B, when the electric field between the two electrode layers 230 is equal to 0 (i.e., E = 0), the birefringent liquid crystal 612a in the liquid crystal cell 612 changes the polarization direction of the light beam L2. As a result, when the polarized light L3 enters the Fresnel lens portion 620, the equivalent refractive index of the birefringent liquid crystal 622 is the long-axis refractive index n _e . Since the refractive index n _{e of the} optical material layer 630 and the equivalent refractive index n _{e of the} birefringent liquid crystal 622 are the same, the polarized light L3 does not refract in the interface between the Fresnel lens portion 620 and the optical material layer 630, and It is directly penetrating the Fresnel lens portion 620 and the optical material layer 630. That is, in the present embodiment, when the electric field provided by the two electrode layer 230 is applied to the variable polarization unit 610, the adjustable variable Fresnel lens 600 is in a closed state, so that the image frame is not affected.

It is worth mentioning that in the present embodiment, the birefringent liquid crystal 622 is, for example, a positive liquid crystal, and the single refractive index n _{x of the} optical material layer 630 is substantially the same as the long-axis refractive index n _{e of the} birefringent liquid crystal 622. However, in other embodiments, the single refractive index n _x may also be between the short-axis refractive index n _o and the long-axis refractive index n _e , that is, the short-axis refractive index n _o <single refractive index n _x long The axial refractive index n _e .

In addition, in other embodiments, the birefringent liquid crystal 422 may also be a negative liquid crystal, wherein the negative-axis liquid crystal has a long-axis refractive index n _e smaller than the short-axis refractive index n _o . In addition, the single refractive index n _{x of the} optical material layer 630 is, for example, between the long-axis refractive index n _e and the short-axis refractive index n _o , that is, the long-axis refractive index n _e <single refractive index n _x < short-axis refraction Rate n _o . Under the above circumstances, the designer can also design the arrangement of the birefringent liquid crystal 622 on the Fresnel lens portion 620 according to the single refractive index n _x and provide polarization of different polarization directions by the variable polarization unit 610. Light is caused to cause the Fresnel lens portion 620 to change the refractive index of the polarized light L1. In this way, the electric field can also be used to switch the Fresnel lens 600. Since the applied principle is the same as the foregoing example, it will not be described here.

In addition, although the birefringent liquid crystal 622a of the present embodiment changes the polarization direction of the light ray L2 without an applied electric field, in other In the embodiment, the birefringent liquid crystal 622a may also change the polarization direction of the light ray L2 in the presence of an applied electric field.

In summary, since the adjustable variable Fresnel lens of the embodiment of the present invention is adapted to change the refractive index of the Fresnel lens portion to polarized light by changing the electric field or adjusting the variable polarization unit, The design requirements decided to turn the adjustable Fresnel lens on or off.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art can make some modifications and refinements without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

100, 300, 400, 600‧‧ Fresnel lenses

110, 310, 420‧‧ Fresnel lens

112, 312, 412a, 422, 612a, 622‧‧‧ birefringent liquid crystal

120, 320, 430, 630‧‧ ‧ optical material layer

130, 230‧‧‧ electrode layer

200, 500‧‧‧ display panel

410, 610‧‧‧ adjustable variable polarization unit

412, 612‧‧‧ liquid crystal cell

D1‧‧‧ long axis

D2‧‧‧ short axis

L1, L3‧‧‧ polarized light

L2‧‧‧Light

S1‧‧‧ into the glossy surface

S2‧‧‧ shiny surface

S3‧‧‧ joint surface

S4‧‧‧ top surface

n _e ‧‧‧Long-axis refractive index

n _o ‧‧‧Short-axis refractive index

n _x ‧‧‧refractive index

1A is a cross-sectional view showing a variable-variable Fresnel lens and a display panel according to a first embodiment of the present invention.

FIG. 1B is another schematic cross-sectional view of a variable-variable Fresnel lens and a display panel according to a first embodiment of the present invention.

FIG. 1C is an enlarged schematic view of a birefringent liquid crystal.

2A is a cross-sectional view showing a variable-variable Fresnel lens and a display panel according to a second embodiment of the present invention.

2B is another schematic cross-sectional view of a variable-variable Fresnel lens and a display panel according to a second embodiment of the present invention.

3A is a cross-sectional view showing a variable-variable Fresnel lens and a display panel according to a third embodiment of the present invention.

FIG. 3B is another schematic cross-sectional view of the adjustable variable Fresnel lens and the display panel according to the third embodiment of the present invention.

4A is a cross-sectional view showing a variably variable Fresnel lens and a display panel according to a fourth embodiment of the present invention.

4B is another schematic cross-sectional view of a variable-variable Fresnel lens and a display panel according to a fourth embodiment of the present invention.

100‧‧‧ Fresnel lens

110‧‧‧ Fresnel lens section

112‧‧‧birefringent liquid crystal

120‧‧‧Optical material layer

130‧‧‧electrode layer

200‧‧‧ display panel

D2‧‧‧ short axis

L1‧‧‧ polarized light

S1‧‧‧ into the glossy surface

S2‧‧‧ shiny surface

S3‧‧‧ joint surface

S4‧‧‧ top surface

n _o ‧‧‧Short-axis refractive index

n _x ‧‧‧refractive index

Claims (18)

An adjustable variable Fresnel lens adapted to pass a polarized light, the adjustable variable Fresnel lens comprising: a Fresnel lens portion having a light incident surface and a light exit surface, wherein the Fresnel The lenticular lens portion has birefringence, and the material of the Fresnel lens portion includes a birefringent liquid crystal, the polarized light enters the Fresnel lens portion from the light incident surface, and exits the Fresnel lens from the illuminating surface And the refractive index of the Fresnel lens portion is adapted to be modulated by an electric field; and an optical material layer disposed on the light exit surface of the Fresnel lens portion, wherein the optical material layer Has a single refractive index n _x . The variably variable Fresnel lens of claim 1, wherein the birefringent liquid crystal comprises a positive liquid crystal having a major axis refractive index n _e and a short axis refractive index n _o , and the long-axis refractive index n _{e is} greater than the short-axis refractive index n _o . The variable-variable Fresnel lens of claim 2, wherein the short-axis refractive index n _o < single refractive index n _x < long-axis refractive index n _e . The variably variable Fresnel lens of claim 2, wherein the single refractive index n _x is substantially equal to the short-axis refractive index n _o or the long-axis refractive index n _e . The variably variable Fresnel lens of claim 1, wherein the birefringent liquid crystal comprises a negative liquid crystal having a major axis refractive index n _e and a short axis refractive index n _o , and the long-axis refractive index n _{e is} smaller than the short-axis refractive index n _o . The variable-variable Fresnel lens of claim 5, wherein the long-axis refractive index n _e < single refractive index n _x < short-axis refractive index n _o . The variably variable Fresnel lens of claim 5, wherein the single refractive index n _x is substantially equal to the short-axis refractive index n _o or the long-axis refractive index n _e . The variably variable Fresnel lens of claim 1, further comprising a two-electrode layer, wherein the Fresnel lens portion and the optical material layer are disposed between the two electrodes, and the Fresnel The refractive index of the polarized light of the lens portion is adapted to be modulated by the electric field provided by the two electrode layers. The variegated Fresnel lens of claim 1, wherein the optical material layer has an engaging surface and a top surface, the engaging surface engaging the light exiting surface of the Fresnel lens portion, and The top surface is a flat surface. An adjustable variable Fresnel lens adapted to pass a light beam, the adjustable variable Fresnel lens comprising: an adjustable variable polarization unit adapted to convert the light into a polarized light, wherein the adjustable The variable polarization unit determines a polarization direction of the polarized light; a Fresnel lens portion having a light incident surface and a light exit surface, wherein the Fresnel lens portion has birefringence, and the material of the Fresnel lens portion includes a birefringent liquid crystal that enters the Fresnel lens portion from the light incident surface and exits the Fresnel lens portion from the light exit surface, and the adjustable variable polarization unit is adapted to provide different polarization directions The polarized light is such that the refractive index of the Fresnel lens portion changes to the polarized light; and an optical material layer disposed on the light exiting surface of the Fresnel lens portion, wherein the optical material layer has a single refractive index n _x . The variably variable Fresnel lens of claim 10, wherein the birefringent liquid crystal comprises a positive liquid crystal having a major axis refractive index n _e and a short axis refractive index n _o , and the long-axis refractive index n _{e is} greater than the short-axis refractive index n _o . The variably variable Fresnel lens of claim 11, wherein the short-axis refractive index n _o < single refractive index n _x < long-axis refractive index n _e . The application of the adjustable item Variant patentable scope of the Fresnel lens 11, wherein the single refractive index n _x minor axis substantially equal to the major axis of the refractive index of the refractive index n _o or n _e. The variably variable Fresnel lens of claim 10, wherein the birefringent liquid crystal comprises a negative liquid crystal having a major axis refractive index n _e and a short axis refractive index n _o , and the long-axis refractive index n _{e is} smaller than the short-axis refractive index n _o . The variable-variable Fresnel lens of claim 14, wherein the long-axis refractive index n _e < single refractive index n _x < short-axis refractive index n _o . The variably variable Fresnel lens of claim 14, wherein the single refractive index n _x is substantially equal to the short-axis refractive index n _o or the long-axis refractive index n _e . The variegated Fresnel lens of claim 10, wherein the optical material layer has an engaging surface and a top surface that engages the light exiting surface of the Fresnel lens portion, and The top surface is a flat surface. The variably variable Fresnel lens of claim 10, wherein the variably variable polarization unit comprises a liquid crystal cell.