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 diffusion light 31 and the liquid crystal lens 40 is divided into a plurality of segments. For each segment, a transmission state 41 in which the diffusion light 31 from the backlight 30 is transmitted and emitted and a light condensed state 42 in which the diffusion light 31 from the backlight 30 is condensed and emitted with the degree of diffusion reduced 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 diffused light, and the liquid crystal lens is divided into a plurality of segments, and each of the plurality of segments can be independently switched between a transmissive state in which the diffused light from the backlight is transmitted and emitted, and a concentrating state in which the diffused light from the backlight is concentrated and emitted with a reduced degree of diffusion. [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 the liquid crystal lens of the first embodiment. [Figure 2] FIG. 1 is a cross-sectional view of a liquid crystal display device according to a first embodiment. [Figure 3] FIG. 2 is a cross-sectional view of the liquid crystal lens of the first embodiment. [Figure 4] FIG. 2 is a plan view of a first substrate in the liquid crystal lens of the first embodiment. [Figure 5] FIG. 3 is a plan view of a second substrate in the liquid crystal lens of the first embodiment. [Figure 6] 4A and 4B are cross-sectional views illustrating the operation of the liquid crystal lens of the first embodiment. [Figure 7] FIG. 10 is a plan view of a driving electrode according to a second embodiment. [Figure 8] FIG. 10 is a plan view of a driving electrode according to a third embodiment. [Figure 9] FIG. 10 is a perspective view of a backlight according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

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

[0011] Fig. 1 is a top view of the liquid crystal lens of Example 1. Fig. 2 is a cross-sectional view of the liquid crystal display device of Example 1. 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 diffused light 31. The backlight 30 may be, for example, a sidelight type backlight having a light guide plate and a light source such as an LED arranged at the end of the light guide plate, or a direct type backlight that does not use a light guide plate and has a light source and a diffusion sheet that diffuses light from the light source.

[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 can independently switch between a transmissive state 41, in which the diffused light 31 from the backlight 30 is transmitted and emitted, and a concentrating state 42, in which the diffused light 31 from the backlight 30 is concentrated and emitted with a reduced degree of diffusion, for each of the multiple segments.

[0017] For example, segment A12 is in the transmissive state 41, and transmits diffused light 31 from backlight 30 and emits it as diffused light 41A. In the transmissive state 41, incident light is transmitted and emitted almost unchanged, so diffused light 41A remains diffused light with the same degree of diffusion as diffused light 31. FIG. 1 shows an example in which segments A21 and A22 are also in the transmissive state 41, just like segment A12.

[0018] In contrast, segment A11 is in a light-collecting state 42, where it collects diffused light 31 from backlight 30, weakens the degree of diffusion, and emits collimated light 42A. Collimated light 42A has a higher front luminance than diffused light 41A, so segment A11 is brighter than segment A12. Note that, while it is desirable for the light emitted in light-collecting state 42 to be collimated light, this is not a limitation, and it may be diffused light that is less diffused than diffused light 31. Even in this case, segment A11 is brighter than segment A12.

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

[0020] FIG. 3 is a cross-sectional view of the liquid crystal lens of the first embodiment.

[0021] The liquid crystal lens 40 of this embodiment has a first substrate 43, a second substrate 44, a liquid crystal layer 45 disposed between the first substrate 43 and the second substrate 44, and a plurality of electrodes 46, and is capable of switching between a transmissive state 41 and a condensing state 42 by applying a predetermined voltage to each of the plurality of electrodes 46. The plurality of electrodes 46 are preferably made of transparent electrodes so as to block as little of the diffused light 31 as possible. Note that the number and size of the plurality of electrodes 46 are exaggerated for clarity in the drawing, and therefore it is desirable that they be smaller and that a greater number of them be disposed in practice.

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

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

[0024] 4, the drawing wires and terminals for applying predetermined voltages to the drive electrodes 46B are not shown, and only the electrical connections using the drawing wires are shown by lines. A voltage E2 is applied to the drive electrodes 46B in the segment A11, a voltage E3 is applied to the segment A12, a voltage E4 is applied to the segment A21, and a voltage E5 is applied to the segment A22.

[0025] FIG. 5 is a plan view of the second substrate in the liquid crystal lens of the first 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] 6 is a cross-sectional view illustrating the operation of the liquid crystal lens of Example 1. FIG. 6 corresponds to an enlarged view of a part of FIG.

[0028] In the absence of an electric field, the liquid crystal molecules in the liquid crystal layer 45 are oriented with their longitudinal direction parallel to 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 drive electrode 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 results in a light-condensing state 42. In the light-condensing state 42, a virtual convex lens 47 is formed. Furthermore, by setting the voltage between the common electrode 46A and the drive electrode 46B to zero or a value smaller than a predetermined value, a state in which there is no electric field or the electric field is weak can be achieved, resulting in a transmissive state 41.

[0029] 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. [Example]

[0030] FIG. 7 is a plan view of the driving electrode of the second embodiment.

[0031] Example 2 is a modification of Example 1, in which the driving electrode 46B is a honeycomb-shaped electrode. The driving electrode 46B has hexagonal openings 46C and is arranged in a honeycomb pattern. While the driving electrode 46B in segment A11 is illustrated here, the same applies to the other segments.

[0032] According to this embodiment, light that diffuses in the vertical direction in FIG. 7 can also be collected, so that the front luminance in the light collection state 42 can be made higher than that of the first embodiment. [Example]

[0033] FIG. 8 is a plan view of the driving electrode of the third embodiment.

[0034] Example 3 is a modification of Example 1, in which the driving electrode 46B is an electrode having a circular opening 46C. The driving electrode 46B has a circular opening 46C. Although the driving electrode 46B in the segment A11 is illustrated here, the same applies to the other segments.

[0035] In this embodiment, since light diffusing in the vertical direction in FIG. 8 can also be collected, the front luminance in the light collection state 42 can be made higher than in the first embodiment. [Example]

[0036] FIG. 9 is a perspective view of the backlight of the fourth embodiment.

[0037] The fourth embodiment is an embodiment that explains an example of the structure of the backlight 30 explained in the first embodiment.

[0038] The backlight 30 of this embodiment is a side light type backlight, as shown in Fig. 9. The backlight 30 emits diffused 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 on which the light source 35 is mounted 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.

[0039] 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.

[0040] 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]

[0041] 10:LCD display device 20: LCD display panel 30: Backlight 31: Diffused light 32: Reflective sheet 33: Light guide plate 34: Prism sheet 35: Light source 36: Light source board 40: Liquid crystal lens 41:Transparent state 41A: Diffused light 42: Focused state 42A: Collimated light 43: First substrate 44: Second board 45: Liquid crystal layer 46: Electrode 46A: Common electrode 46B: Drive electrode 46C:Aperture 47: Convex lens A11, A12, A21, A22: Segments E1~E5: 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 diffused light; The liquid crystal lens is divided into a plurality of segments, and each of the plurality of segments can be independently switched between a transmissive state in which the diffused light from the backlight is transmitted and emitted, and a concentrating state in which the diffused light from the backlight is concentrated and emitted with a reduced degree of diffusion.

2. In claim 1, The liquid crystal display device is characterized in that the light emitted from the liquid crystal lens in the light-condensing state is collimated light.

3. 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 transmissive state and the light-collecting state by applying a predetermined voltage to each of the plurality of electrodes.

4. In claim 3, A liquid crystal display device characterized in that the plurality of electrodes include a drive electrode formed on the first substrate to which a voltage is applied independently for each of the segments, and a common electrode formed on the second substrate to cover the entire surfaces of the plurality of segments.

5. In claim 4, 10. A liquid crystal display device, wherein the driving electrodes are stripe-shaped electrodes.

6. In claim 4, The liquid crystal display device is characterized in that the drive electrodes are honeycomb electrodes.

7. In claim 4, 10. A liquid crystal display device, wherein the drive electrode is an electrode having a circular opening.

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