Liquid crystal display device

Abstract

To provide a liquid crystal display device that can perform partial driving with a simple structure.SOLUTION: A liquid crystal display device 10 includes a liquid crystal display panel 20, a backlight 30 disposed on a rear surface of the liquid crystal display panel 20, and a liquid crystal lens 40 disposed between the liquid crystal display panel 20 and the backlight 30. The backlight 30 emits collimated light 31. The liquid crystal lens 40 includes a light-blocking layer 48 provided in a part of a region on a side where the liquid crystal display panel 20 is disposed. The liquid crystal lens 40 is divided into a plurality of segments. For each segment, a light-blocking state 41 in which the collimated light 31 from the backlight 30 is condensed in the light-blocking layer 48 and an emission state 42 in which the collimated light 31 from the backlight 30 is condensed in a region where the light-blocking layer 48 is not provided and emitted can be independently switched.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a liquid crystal display device. [Background technology]

[0002] In order to improve image quality, a liquid crystal display device may perform local dimming, in which the backlight is divided into a plurality of segments and partially illuminated.

[0003] For example, Figures 3 and 8 to 10 of Patent Document 1 describe a technology in which one LED (60) is arranged in each segment (141) that performs local dimming, and each segment (141) is separated by a partition plate (70). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-74264 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technique described in Patent Document 1 has a problem in that as the number of segments increases, the number of LEDs also increases, resulting in higher costs.

[0006] An object of the present invention is to provide a liquid crystal display device that can perform partial driving with a simple configuration. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the liquid crystal display device of the present invention comprises a liquid crystal display panel, a backlight arranged on the back of the liquid crystal display panel, and a liquid crystal lens arranged between the liquid crystal display panel and the backlight, wherein the backlight emits collimated light, the liquid crystal lens has a light-shielding layer provided in a partial area on the side where the liquid crystal display panel is arranged, and the liquid crystal lens is divided into a plurality of segments, and each of the plurality of segments is capable of independently switching between a light-shielding state in which the collimated light from the backlight is focused on the light-shielding layer to block the light, and an emission state in which the collimated light from the backlight is focused on an area where the light-shielding layer is not provided and emitted. [Effects of the Invention]

[0008] According to the present invention, it is possible to realize a liquid crystal display device that can perform partial driving with a simple configuration. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a top view of a liquid crystal lens according to an embodiment. [Figure 2] FIG. 1 is a cross-sectional view of a liquid crystal display device according to an embodiment. [Figure 3] FIG. 2 is a cross-sectional view of a liquid crystal lens according to an embodiment. [Figure 4] FIG. 2 is a plan view of a first substrate in the liquid crystal lens of the embodiment. [Figure 5] FIG. 3 is a plan view of a second substrate in the liquid crystal lens of the embodiment. [Figure 6] 5A and 5B are cross-sectional views illustrating the operation of the liquid crystal lens in a light blocking state according to the embodiment. [Figure 7] 5A and 5B are cross-sectional views illustrating the operation of the liquid crystal lens in the emission state according to the embodiment. [Figure 8] FIG. 2 is a perspective view of a backlight according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In each drawing, the same or similar components are designated by the same reference numerals, and redundant explanations will be omitted.

[0011] Fig. 1 is a top view of a liquid crystal lens of an embodiment. Fig. 2 is a cross-sectional view of a liquid crystal display device of an embodiment. The position of the cross section in Fig. 2 corresponds to the position AA in Fig. 1.

[0012] 2, the liquid crystal display device 10 of this embodiment includes a liquid crystal display panel 20, a backlight 30 disposed on the rear surface of the liquid crystal display panel 20, and a liquid crystal lens 40 disposed between the liquid crystal display panel 20 and the backlight 30. The liquid crystal display device 10 also includes, for example, an optical sheet, a control device, a housing, and the like, which are not shown in the drawings.

[0013] The liquid crystal display panel 20 has, for example, an upper substrate, a lower substrate, a liquid crystal layer sandwiched between the upper and lower substrates, electrodes for driving the liquid crystal layer, an upper polarizer arranged above the upper substrate, and a lower polarizer arranged below the lower substrate.

[0014] The backlight 30 is a surface-emitting lighting device. The backlight 30 of this embodiment emits collimated light 31.

[0015] 1 and 2, the liquid crystal lens 40 is divided into a plurality of segments. In this embodiment, an example will be described in which the lens is divided into four segments (A11, A12, A21, and A22), two segments in the vertical direction and two segments in the horizontal direction. Note that the segment division method and the number of divisions are merely examples and are not limited to these.

[0016] The liquid crystal lens 40 of this embodiment has a light-shielding layer 48 provided in a partial region on the side where the liquid crystal display panel 20 is disposed. The liquid crystal lens 40 of this embodiment can independently switch, for each of the multiple segments, between a light-shielding state 41 in which collimated light 31 from the backlight 30 is condensed on the light-shielding layer 48 and blocked, and an emission state 42 in which the collimated light 31 from the backlight 30 is condensed in a region where the light-shielding layer 48 is not provided and emitted.

[0017] For example, segment A12 is in the light-blocking state 41, and collimated light 31 from backlight 30 is condensed onto light-blocking layer 48, blocking the light. This achieves a dark state during partial driving. Figure 1 shows an example in which segments A21 and A22 are also in the light-blocking state 41, similar to segment A12.

[0018] In contrast, segment A11 is in the emission state 42, and collimated light 31 from the backlight 30 is condensed and emitted to an area where no light-shielding layer 48 is provided. This achieves a bright state of partial driving. Because the emitted light 42A is diffused light, brightness can be ensured not only in the front direction but also in oblique directions.

[0019] As described above, by combining the backlight 30 that emits collimated light 31 with the liquid crystal lens 40 and independently switching between the light-blocking state 41 and the light-emitting state 42 for each segment using the liquid crystal lens 40, partial driving can be performed in which the light from the backlight 30 is divided into multiple segments and partially illuminated.

[0020] FIG. 3 is a cross-sectional view of a liquid crystal lens according to an embodiment.

[0021] The liquid crystal lens 40 of this embodiment includes a first substrate 43, a second substrate 44, a liquid crystal layer 45 disposed between the first substrate 43 and the second substrate 44, multiple electrodes 46, and a light-shielding layer 48. The liquid crystal lens 40 can be switched between a light-shielding state 41 and an emission state 42 by applying a predetermined voltage to each of the multiple electrodes 46. The multiple electrodes 46 are preferably transparent electrodes so as to minimize blocking of the collimated light 31. The number and size of the multiple electrodes 46 are exaggerated for clarity; in practice, the electrodes 46 are preferably smaller and more numerous. The same applies to the number and size of the light-shielding layers 48. In this embodiment, some of the light-shielding layers 48 are omitted from FIG. 2 for clarity. Details of FIG. 3 will be described later, also with reference to FIGS. 6 and 7.

[0022] FIG. 4 is a plan view of a first substrate in the liquid crystal lens of the embodiment.

[0023] The multiple electrodes 46 include first drive electrodes 46B and second drive electrodes 46C formed on the first substrate 43, to which voltages are applied independently for each segment. In this embodiment, as an example, the first drive electrodes 46B and second drive electrodes 46C are shown as stripe-shaped electrodes. Specifically, the first drive electrodes 46B and second drive electrodes 46C extend in a first direction (the vertical direction in the figure in this embodiment) and are arranged side by side in a second direction (the horizontal direction in the figure in this embodiment) different from the first direction. The first drive electrodes 46B and second drive electrodes 46C are arranged alternately.

[0024] 4 does not show the lead-out wiring and terminals for applying predetermined voltages to the first drive electrode 46B and the second drive electrode 46C, and only the electrical connection relationship using the lead-out wiring is shown by lines. In segment A11, a voltage E2 is applied to the first drive electrode 46B, and a voltage E3 is applied to the second drive electrode 46C. Similarly, in segment A12, a voltage E4 is applied to the first drive electrode 46B, and a voltage E5 is applied to the second drive electrode 46C. In segment A21, a voltage E6 is applied to the first drive electrode 46B, and a voltage E7 is applied to the second drive electrode 46C. In segment A22, a voltage E8 is applied to the first drive electrode 46B, and a voltage E9 is applied to the second drive electrode 46C.

[0025] FIG. 5 is a plan view of the second substrate in the liquid crystal lens of the embodiment.

[0026] The multiple electrodes 46 include a common electrode 46A formed on the second substrate 44 and covering the entire surfaces of the multiple segments. The common electrode 46A is a so-called solid electrode. A voltage E1 is applied to the common electrode 46A. The voltage E1 is preferably supplied to the common electrode 46A from a terminal provided on the first substrate 43, for example, via an inter-substrate connecting conductive member that connects the first substrate 43 and the second substrate 44.

[0027] A light-shielding layer 48 is also formed on the second substrate 44, but is not shown in the figure. The light-shielding layer 48 is preferably disposed in a position facing the second drive electrode 46C. Therefore, the light-shielding layer 48 is formed, for example, in a striped pattern. The light-shielding layer 48 can be formed, for example, from a resin black used in the color filters of the liquid crystal display panel 20, or a metal such as Al or Mo used in wiring.

[0028] 6 is a cross-sectional view illustrating the operation of the liquid crystal lens in the light blocking state according to the embodiment, which corresponds to an enlarged view of a part of the right half area of ​​FIG.

[0029] In the absence of an electric field, the liquid crystal molecules in the liquid crystal layer 45 are oriented with their longitudinal direction aligned with the major surface of the first substrate 43. As shown in FIG. 6, a voltage equal to or greater than a predetermined threshold is applied between the common electrode 46A and the first drive electrodes 46B to generate an electric field, thereby driving the liquid crystal layer 45 and controlling the orientation of the liquid crystal molecules to the direction of the electric field. This allows the liquid crystal layer 45 to enter a light-shielding state 41. In the light-shielding state 41, a virtual convex lens 47 is formed between the two first drive electrodes 46B, with its end located at the first drive electrode 46B. As a result, as shown in the right half of FIG. 3, collimated light 31 from the backlight 30 is focused by the convex lens 47 onto the light-shielding layer 48, thereby blocking the light.

[0030] Regarding the second drive electrode 46C, by setting the voltage between the common electrode 46A and the second drive electrode 46C to 0 or a value smaller than a predetermined value, it is possible to create a state in which there is no electric field or a weak electric field between the common electrode 46A and the second drive electrode 46C. At this time, an electric field is also generated between the first drive electrode 46B and the second drive electrode 46C, but the liquid crystal molecules affected by this electric field remain in a region close to the first substrate 43, so the effect on the convex lens 47 is small.

[0031] 7 is a cross-sectional view illustrating the operation of the liquid crystal lens in the emission state according to the embodiment, which corresponds to an enlarged view of a part of the left half area of ​​FIG.

[0032] In the emission state 42, a voltage equal to or greater than a predetermined threshold is applied between the common electrode 46A and the second drive electrode 46C to generate an electric field, thereby driving the liquid crystal layer 45 and controlling the orientation of the liquid crystal molecules to follow the electric field. In the emission state 42, a virtual convex lens 47 having an end at the second drive electrode 46C is formed between the two second drive electrodes 46C. Therefore, in the emission state 42, the convex lens 47 can be formed in a position different from that in the light-shielding state 41. As a result, as shown in the left half of FIG. 3, the collimated light 31 from the backlight 30 is condensed by the convex lens 47 in an area where the light-shielding layer 48 is not provided, and is emitted as diffused emission light 42A.

[0033] Regarding first drive electrode 46B, by setting the voltage between common electrode 46A and first drive electrode 46B to 0 or a value smaller than a predetermined value, it is possible to create a state in which there is no electric field or a weak electric field between common electrode 46A and first drive electrode 46B. At this time, an electric field is also generated between first drive electrode 46B and second drive electrode 46C, but the liquid crystal molecules affected by this electric field remain in a region close to first substrate 43, so the effect on convex lens 47 is small.

[0034] As described above, according to this embodiment, unlike the method of performing partial driving by individually driving the LEDs that are the light sources, there is no need to increase the number of LEDs for partial driving even if the number of segments increases, so partial driving can be performed with a simple configuration.

[0035] FIG. 8 is a perspective view of the backlight of the embodiment.

[0036] An example of the structure of a backlight 30 of this embodiment will be described. The backlight 30 of this embodiment is a side light type backlight, as shown in FIG. 8. The backlight 30 emits collimated light 31. The backlight 30 includes a reflective sheet 32, a light guide plate 33, and a prism sheet 34, which are stacked in the Z direction. The light source 35 is disposed on a light source substrate 36 along the Y direction. The light source substrate 36 equipped with the light source 35 is disposed opposite a side surface of the light guide plate 33. Light emitted from the light source 35 in the X direction enters the light guide plate 33 from the side surface of the light guide plate 33 and is emitted from the surface of the light guide plate 33 facing the prism sheet 34.

[0037] According to this embodiment, by using a side light type backlight, a thin backlight 30 can be obtained, and by combining it with the liquid crystal lens 40, partial driving becomes possible.

[0038] Although the embodiments of the present invention have been described above, the present invention is not limited to the configurations described in the embodiments, and various modifications are possible within the scope of the technical concept of the present invention. In addition, some or all of the configurations described in the embodiments may be combined and applied. [Explanation of symbols]

[0039] 10:LCD display device 20: LCD display panel 30: Backlight 31: Collimated light 32: Reflective sheet 33: Light guide plate 34: Prism sheet 35: Light source 36: Light source board 40: Liquid crystal lens 41: Light blocking state 42: Emission state 42A: Output light 43: First substrate 44: Second board 45: Liquid crystal layer 46: Electrode 46A: Common electrode 46B: First drive electrode 46C: Second driving electrode 47: Convex lens 48: Light blocking layer A11, A12, A21, A22: Segments E1~E9: Voltage

Claims

1. A liquid crystal display panel; a backlight disposed on the rear surface of the liquid crystal display panel; a liquid crystal lens disposed between the liquid crystal display panel and the backlight; the backlight emits collimated light; the liquid crystal lens has a light-shielding layer provided in a partial area on a side where the liquid crystal display panel is disposed, The liquid crystal lens is divided into a plurality of segments, and each of the plurality of segments can be independently switched between a light-blocking state in which the collimated light from the backlight is focused on the light-blocking layer and blocked, and an emission state in which the collimated light from the backlight is focused on an area where the light-blocking layer is not provided and emitted.

2. In claim 1, The liquid crystal lens has a first substrate, a second substrate, a liquid crystal layer disposed between the first substrate and the second substrate, and a plurality of electrodes, and is capable of switching between the light-blocking state and the light-emitting state by applying a predetermined voltage to each of the plurality of electrodes.

3. In claim 2, the light-shielding layer is formed on the second substrate, the plurality of electrodes include a first drive electrode and a second drive electrode formed on the first substrate and to which a voltage is applied independently for each of the segments, and a common electrode formed on the second substrate and covering the entire surfaces of the plurality of segments; A liquid crystal display device characterized in that the light-blocking state is achieved by generating an electric field between the first drive electrode and the common electrode, and the emission state is achieved by generating an electric field between the second drive electrode and the common electrode.

4. In claim 3, a first driving electrode and a second driving electrode, the first driving electrode and the second driving electrode being striped electrodes, the first driving electrode and the second driving electrode being alternately arranged;

5. In claim 4, The liquid crystal display device is characterized in that the light-shielding layer is disposed at a position facing the second drive electrode.

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