JP7779223B2 - Liquid crystal light control device, imaging device and adapter device - Google Patents

Description

This disclosure relates to a liquid crystal dimming device, an imaging device, and an adapter device.

Imaging devices commonly used in digital still cameras, video cameras, etc. have a lens and an imaging element located on the optical axis of the lens. Some imaging devices also have a liquid crystal dimming device used as an ND (Neutral Density) filter between the lens and the imaging element. This liquid crystal dimming device makes it possible to adjust the amount of light traveling from the lens to the imaging element. Patent Document 1 below discloses a liquid crystal dimming device that can be used in imaging devices. Patent Document 2 below also discloses a liquid crystal display element formed by injecting liquid crystal through an opening in a sealing portion.

International Publication No. 2020/195177 Japanese Patent Application Publication No. 6-34984

In this field, it is desirable for the liquid crystal to be dispersed as uniformly as possible within the liquid crystal injection layer into which the liquid crystal is injected.

One of the objectives of this disclosure is to provide a liquid crystal dimming device, an imaging device, and an adapter device that are capable of dispersing liquid crystal as uniformly as possible within a liquid crystal injection layer into which the liquid crystal is injected.

The present disclosure provides, for example,
a liquid crystal injection port for injecting liquid crystal into the liquid crystal injection layer surrounded by the sealing portion;
a wall portion for providing asymmetry in the inflow of liquid crystal in a plurality of inflow paths extending from the liquid crystal inlet;
and
the sealing portion has a side portion along a propagation direction in which the liquid crystal propagates from the liquid crystal injection port toward approximately the center of an effective dimming area set within the sealing portion,
the wall portion is provided independently of the sealing portion within the liquid crystal injection layer surrounded by the sealing portion;
Further, the wall portion has a first end and a second end;
the first end is provided at a position closer to the approximate center of the effective dimming area than the second end, and the second end is provided at a position closer to the side than the first end,
The liquid crystal injection port is provided at a position closer to the first end than to the second end.
It is an LCD dimming device.

The present disclosure provides, for example,
An imaging element;
A liquid crystal dimming unit,
a dimming driver that drives the liquid crystal dimming unit;
and
The LCD dimming section is
a liquid crystal injection port for injecting liquid crystal into the liquid crystal injection layer surrounded by the sealing portion;
a wall portion for providing asymmetry in the inflow of liquid crystal in a plurality of inflow paths extending from the liquid crystal inlet;
and
the sealing portion has a side portion along a propagation direction in which the liquid crystal propagates from the liquid crystal injection port toward approximately the center of an effective dimming area set within the sealing portion,
the wall portion is provided independently of the sealing portion within the liquid crystal injection layer surrounded by the sealing portion;
Further, the wall portion has a first end and a second end;
the first end is provided at a position closer to the approximate center of the effective dimming area than the second end, and the second end is provided at a position closer to the side than the first end,
The liquid crystal injection port is provided at a position closer to the first end than to the second end.

The present disclosure provides, for example,
a liquid crystal injection port for injecting liquid crystal into the liquid crystal injection layer surrounded by the sealing portion;
a wall portion for providing asymmetry in the inflow of liquid crystal in a plurality of inflow paths extending from the liquid crystal inlet;
and
the sealing portion has a side portion along a propagation direction in which the liquid crystal propagates from the liquid crystal injection port toward approximately the center of an effective dimming area set within the sealing portion,
the wall portion is provided independently of the sealing portion within the liquid crystal injection layer surrounded by the sealing portion;
Further, the wall portion has a first end and a second end;
the first end is provided at a position closer to the approximate center of the effective dimming area than the second end, and the second end is provided at a position closer to the side than the first end,
The liquid crystal filling port is located closer to the first end than to the second end of the adapter device.

FIG. 1 is a diagram to which reference is made when describing the issues to be considered in this disclosure. FIG. 1 is a diagram to which reference is made when describing the issues to be considered in this disclosure. 1A to 1D are figures to which reference is made when discussing the issues to be considered in this disclosure. 1 is an exploded perspective view of a liquid crystal light control device according to an embodiment. 1 is a cross-sectional view of a liquid crystal light control device according to an embodiment. 10A and 10B are diagrams to be referred to when describing examples of shapes of asymmetric forming portions according to one embodiment. 6A and 6B are enlarged views of a portion of FIG. 10A and 10B are diagrams to be referred to when explaining the function of an asymmetric forming portion according to one embodiment. 10A and 10B are diagrams to be referred to when explaining the function of an asymmetric forming portion according to one embodiment. FIG. 2 is a diagram to be referred to when explaining the liquid crystal injection process. 1A to 1D are diagrams to be referred to when explaining an example of the effect obtained by the liquid crystal light control device according to one embodiment. 1 is a diagram to be referred to when describing an example of application of a liquid crystal light control device according to an embodiment to an imaging device. 1 is a diagram to be referred to when describing an example of application of a liquid crystal light control device according to an embodiment to an imaging device. 1A and 1B are diagrams to be referred to when describing an example of application of a liquid crystal light control device according to an embodiment to an imaging device. 1 is a diagram to be referred to when describing an example of application of a liquid crystal light control device according to an embodiment to an imaging device. 1 is a diagram to be referred to when describing an example of application of a liquid crystal light control device according to an embodiment to an imaging device. FIG. 10 is a diagram for explaining a modified example. FIG. 10 is a diagram for explaining a modified example.

Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. The description will be made in the following order.
<Issues to be considered in this disclosure>
<One embodiment>
<Modification>
The embodiments and the like described below are preferred specific examples of the present disclosure, and the contents of the present disclosure are not limited to these embodiments and the like.

<Issues to be considered in this disclosure>
First, to facilitate understanding of the present disclosure, issues to be considered in the present disclosure will be described. FIG. 1 is a plan view of a typical liquid crystal light control device (liquid crystal light control device 1). FIG. 2 is a cross-sectional view of the liquid crystal light control device 1 taken along line AA-AA in FIG. 1. The liquid crystal light control device 1 can be used, for example, as an ND filter for an imaging device. In the following description, the horizontal direction (left-right direction) in FIG. 1 is defined as the X direction, the vertical direction (up-down direction) as the Y direction, and the direction toward the paper surface (thickness direction) as the Z direction.

The liquid crystal dimming device 1 has an upper glass substrate 2A and a lower glass substrate 2B arranged opposite each other. The gap between the upper glass substrate 2A and the lower glass substrate 2B forms a liquid crystal injection layer 3 into which liquid crystal is injected (filled), and liquid crystal (liquid crystal composition) 4 is injected into this liquid crystal injection layer 3. The periphery of the liquid crystal injection layer 3 is sealed with a sealing portion 5. In addition, bead-shaped spacers 6 are arranged in the liquid crystal injection layer 3 to maintain a gap between the upper glass substrate 2A and the lower glass substrate 2B.

A conductive film 7A and an alignment film 8A are laminated in this order in the -Z direction on the main surface of the upper glass substrate 2A facing the liquid crystal injection layer 3. Furthermore, a conductive film 7B and an alignment film 8B are laminated in this order in the +Z direction on the main surface of the lower glass substrate 2B facing the liquid crystal injection layer 3. The amount of light passing through the liquid crystal dimming device 1 can be controlled by controlling the drive voltage applied to the conductive films 7A and 7B.

Liquid crystal injection ports 9A, 9B, 9C, and 9D are provided near the four corners of the upper glass substrate 2A. These ports are used to inject liquid crystal into the liquid crystal injection layer 3. When there is no need to distinguish between the individual liquid crystal injection ports, they will be referred to collectively as liquid crystal injection port 9. The liquid crystal injection ports 9 communicate with the liquid crystal injection layer 3, and the liquid crystal 4 is injected into the liquid crystal injection layer 3 through the liquid crystal injection ports 9. After the liquid crystal 4 is injected, the liquid crystal injection ports 9 are closed with a plug. For example, liquid crystal injection port 9A is closed with plug 10A, and liquid crystal injection port 9B is closed with plug 10B. While the number of liquid crystal injection ports 10 is four in this example, there may be one, two, or even five or more.

In the in-plane directions (X and Y directions) of the liquid crystal injection layer 3, an effective dimming area AP is defined within the liquid crystal 4 filling area surrounded by the sealing portion 5 (see Figure 1). The effective dimming area AP is an area that ensures effective dimming, and is defined as an area narrower than the entire liquid crystal 4 filling area.

Such a typical liquid crystal dimming device 1 has the following problems. For example, if the liquid crystal injection layer 3 is made up of multiple layers and the alignment directions of the liquid crystal in each liquid crystal injection layer 3 are orthogonal, it is necessary to stack multiple configurations such as those shown in Figure 2, which results in a problem of an increased thickness of the liquid crystal dimming device 1.

Furthermore, when liquid crystal is injected through a liquid crystal injection port 9 located outside the effective dimming area AP, the flow rate of the liquid crystal 4 near the liquid crystal injection port 9 (near the four corners of the effective dimming area AP) increases. This can damage the alignment films 8A and 8B, leading to problems such as white spots caused by peeling of the alignment films 8A and 8B, and in-plane unevenness of the liquid crystal 4.

Figures 3A through 3D are schematic diagrams showing the process of injecting liquid crystal 4 into the liquid crystal injection layer 3 in chronological order. Note that Figures 3A through 3D show simplified views of some of the components, with the liquid crystal 4 indicated by dots. Figure 3A shows the state before the liquid crystal 4 is injected. The liquid crystal 4 is then injected through the liquid crystal injection port 9. As shown in Figures 3B and 3C, the liquid crystal 4 gradually fills the liquid crystal injection layer 3 from the four corners where the liquid crystal injection ports 9 are located. Then, as shown in Figure 3D, the flow of liquid crystal 4 eventually converges near the center of the effective dimming area AP. If the flow of liquid crystal 4 converges near the center in this way, there is a risk that the spacers 6 and any remaining gas in the liquid crystal injection layer 3 will collect near the center. Furthermore, there is a risk that the spacers 6 will aggregate near the center, increasing the risk of image quality problems such as the generation of bright spots.

In addition, with the technology described in Patent Document 2, liquid crystal is injected through an opening in the sealing section, so if there are multiple liquid crystal injection layers, an opening must be provided in each of the sealing sections. This requires injecting liquid crystal into each of the multiple liquid crystal injection layers, which may complicate the process. Furthermore, with the technology described in Patent Document 2, the liquid crystal inflow path starting from the liquid crystal injection port is symmetrical, which may prevent effective reduction of the load on the alignment film during liquid crystal injection. Taking the above points into consideration, the contents of the present disclosure will be described in detail with reference to embodiments.

<One embodiment>
[Configuration example of liquid crystal light control device]
First, a configuration example of a liquid crystal light control device (liquid crystal light control device 100) according to this embodiment will be described with reference to Figures 4 and 5. Figure 4 is an exploded perspective view of the liquid crystal light control device 100. Figure 5 is a cross-sectional view showing a cross section of the liquid crystal light control device 100 taken along the cutting line BB-BB in Figure 4. In the following description, the surface of each component located on the +Z direction side will be referred to as the front surface or upper surface, and the surface located on the -Z direction side will be referred to as the back surface or lower surface.

As shown in FIG. 4, the liquid crystal dimming device 100 has a configuration in which, for example, an upper substrate 11, a first sealing portion 21, a middle substrate 12, a second sealing portion 22, and a lower substrate 13 are stacked in this order from top to bottom. That is, the first sealing portion 21 is interposed between the upper substrate 11 and the middle substrate 12, and the second sealing portion 22 is interposed between the middle substrate 12 and the lower substrate 13. The area surrounded by the first sealing portion 21 (the area inside the first sealing portion 21) forms a first liquid crystal injection layer 25 into which liquid crystal is injected. A first liquid crystal layer 25A (see FIG. 5) is formed by injecting liquid crystal into the first liquid crystal injection layer 25. The area surrounded by the second sealing portion 22 (the area inside the second sealing portion 22) forms a second liquid crystal injection layer 26 into which liquid crystal is injected. A second liquid crystal layer 26A (see FIG. 5) is formed by injecting liquid crystal into the second liquid crystal injection layer 26.

In this embodiment, GH liquid crystal (guest-host liquid crystal) is used as the liquid crystal that constitutes the first liquid crystal layer 25A and the second liquid crystal layer 26A. By aligning the liquid crystal between the two liquid crystal layers in a crossed Nicol configuration, image quality is improved when the liquid crystal dimming device 100 is applied to an imaging device.

The upper substrate 11, middle substrate 12, and lower substrate 13 are glass substrates that separate the first liquid crystal layer 25A and the second liquid crystal layer 26A. The upper substrate 11 is the uppermost substrate, the lower substrate 13 is the lowermost substrate, and the middle substrate 12 is a glass substrate that is positioned between the upper substrate 11 and the lower substrate 13.

The upper substrate 11 and the middle substrate 12 are joined by a first seal 21. For example, the first seal 21 joins the periphery of the upper substrate 11 to the periphery of the middle substrate 12. The middle substrate 12 and the lower substrate 13 are joined by a second seal 22. For example, the second seal 22 joins the periphery of the middle substrate 12 to the periphery of the lower substrate 13. An adhesive such as an epoxy adhesive or an acrylic adhesive is used as the first seal 21 and the second seal 22.

As described above, in this embodiment, the liquid crystal dimming device 100 has two liquid crystal layers (first liquid crystal layer 25A and second liquid crystal layer 26A). Corresponding to this configuration, a total of four electrodes are formed: two electrodes serving as counter electrodes for one liquid crystal layer and two electrodes serving as counter electrodes for the other liquid crystal layer. Accordingly, four terminals are also formed. For example, ITO (Indium Tin Oxide) can be used as the electrodes. Alternatively, ITO with an AR (Anti-Reflection) film laminated thereon can be used.

Specifically, a first electrode E1 is formed on the back surface 11B of the upper substrate 11. A first terminal T1 corresponding to the first electrode E1 is formed on the front surface 12A of the middle substrate 12. The second terminal T2 is a terminal corresponding to the second electrode E2 formed on the front surface 12A of the middle substrate 12. The second terminal T2 is a terminal formed as part of the second electrode E2 formed on the front surface 12A of the same middle substrate 12. Note that there is a gap in the thickness direction (Z direction) between the first electrode E1 formed on the upper substrate 11 and the first terminal T1 formed on the middle substrate 12. For this reason, a silver point 31 is provided between the upper substrate 11 and the middle substrate 12 to electrically connect the first terminal T1 and the first electrode E1.

The third terminal T3 corresponds to the third electrode E3 formed on the back surface 12B of the middle substrate 12, and the fourth terminal T4 corresponds to the fourth electrode E4 formed on the front surface 13A of the lower substrate 13. The fourth terminal T4 is formed as part of the fourth electrode E4 formed on the front surface 13A of the lower substrate 13. A gap exists in the thickness direction of the liquid crystal dimming device 100 between the third terminal T3 formed on the lower substrate 13 and the third electrode E3 formed on the middle substrate 12. Therefore, a silver point 32 electrically connecting the third terminal T3 and the third electrode E3 is provided between the middle substrate 12 and the lower substrate 13. The silver points 31 and 32 are made of, for example, conductive carbon. To avoid cluttering the illustration, FIG. 5 omits the alignment films laminated on the first electrode E1, second electrode E2, third electrode E3, and fourth electrode E4, as well as the spacers disposed between the substrates.

A cable-equipped connector (not shown) is connected to the first terminal T1, the second terminal T2, the third terminal T3, and the fourth terminal T4. A liquid crystal drive signal SP1 is supplied to the pair of first terminal T1 and second terminal T2 via the cable-equipped connector. The liquid crystal drive signal SP1 controls the orientation of the liquid crystal that constitutes the first liquid crystal layer 25A. A liquid crystal drive signal SP2 is supplied to the pair of third terminal T3 and fourth terminal T4. The liquid crystal drive signal SP2 controls the orientation of the liquid crystal that constitutes the second liquid crystal layer 26A.

The lower substrate 13 is formed with liquid crystal injection ports 36 for injecting liquid crystal into the first liquid crystal injection layer 25 and the second liquid crystal injection layer 26. In this embodiment, the liquid crystal injection ports 36 include four liquid crystal injection ports 36A, 36B, 36C, and 36D. The four liquid crystal injection ports are provided at positions on the lower substrate 13 that correspond to positions near the four corners of the second liquid crystal injection layer 26 when viewed in a plan view. Note that when there is no need to distinguish between the four liquid crystal injection ports, they will be collectively referred to as liquid crystal injection ports 36.

The middle substrate 12 is formed with a liquid crystal injection port 37 for injecting liquid crystal into the first liquid crystal injection layer 25. In this embodiment, the liquid crystal injection port 37 includes four liquid crystal injection ports 37A, 37B, 37C, and 37D. The four liquid crystal injection ports are provided at positions on the middle substrate 12 that correspond to positions near the four corners of the first liquid crystal injection layer 25 when viewed in a plan view. Note that when there is no need to distinguish between the four liquid crystal injection ports, they will be collectively referred to as liquid crystal injection ports 37.

The liquid crystal injection port 36 penetrates the lower substrate 13, and the liquid crystal injection port 37 penetrates the middle substrate 12. In this embodiment, the liquid crystal injection ports 36 and 37 are formed to have the same shape and size. Furthermore, their formation positions overlap in the in-plane direction; in other words, they are arranged so that their formation positions overlap in the thickness direction (the Z direction, the stacking direction of the first liquid crystal injection layer 25 and the second liquid crystal injection layer 26). Specifically, the formation positions of the liquid crystal injection ports 36A and 37A overlap in the in-plane direction and thickness direction. Furthermore, the formation positions of the liquid crystal injection ports 36B and 37B overlap in the in-plane direction and thickness direction. Furthermore, the formation positions of the liquid crystal injection ports 36C and 37C overlap in the in-plane direction and thickness direction. Furthermore, the formation positions of the liquid crystal injection ports 36D and 37D overlap in the in-plane direction and thickness direction. The liquid crystal injection port 37 located between the layers communicates with the first liquid crystal injection layer 25 and the second liquid crystal injection layer 26.

As will be described in detail later, liquid crystal is injected into the first liquid crystal injection layer 25 and the second liquid crystal injection layer 26 through the liquid crystal injection port 36 and the liquid crystal injection port 37. After the liquid crystal is injected, the liquid crystal injection port 36 is closed with the stopper material 41. Specifically, the liquid crystal injection ports 36A to 36D are closed with the corresponding stopper materials 41A to 41D, respectively (see FIG. 5). After the liquid crystal is injected, the liquid crystal injection port 37 is closed with the stopper material 42. Specifically, the liquid crystal injection ports 37A to 37D are closed with the corresponding stopper materials 42A to 42D, respectively (see FIG. 5). The stopper materials 41 and 42 are the same stopper material, and for example, a hardened adhesive can be used.

The components of the liquid crystal light control device 100 described above are examples, and the liquid crystal light control device 100 may include components other than those described above. For example, in FIG. 4, the area of each electrode that protrudes in the -X direction may be used as a monitoring area for optical density. A connector equipped with a sensor for detecting optical density may be connected to this monitoring area.

[Regarding asymmetric formations]
(Example of shape)
6 and 7, an example of an asymmetric forming portion of the liquid crystal light control device 100 will be described. Fig. 6 is a plan view of the surface 12A of the middle substrate 12 on which the first seal portion 21 is formed. Fig. 7A is a partial enlarged view of the area surrounded by the dotted line PA in Fig. 6, and Fig. 7B is a partial enlarged view of the area surrounded by the dotted line PB in Fig. 6.

As shown in FIG. 6, the first sealing portion 21 is roughly frame-shaped. An effective dimming area AP is defined within the area enclosed by the first sealing portion 21. The effective dimming area AP is an area that ensures that dimming works effectively, and is defined as an area narrower than the entire liquid crystal filling area in the first liquid crystal injection layer 25. A reference position RP is set approximately in the center of the effective dimming area AP. Note that the reference position RP can be set to an appropriate position different from approximately the center of the effective dimming area AP. Although not shown in the figure, an effective dimming area AP is also defined within the area enclosed by the second sealing portion 22.

Specifically, the first seal portion 21 has a first side portion 21A, a second side portion 21B opposite the first side portion 21A, a third side portion 21C connecting the first side portion 21A and the second side portion 21B, and a fourth side portion 21D opposite the third side portion 21C. The first side portion 21A, the second side portion 21B, and the third side portion 21C are straight sides. The fourth side portion 21D has linear portions 21DA and 21DB extending from the respective ends, a bent portion 21DC that bends diagonally upward from the tip of linear portion 21DA toward the inside, a bent portion 21DD that bends diagonally downward from the tip of linear portion 21DB toward the inside, and a linear portion 21DE that connects the tip of bent portion 21DC with the tip of bent portion 21DD.

The asymmetric forming portion is intended to impart asymmetry to the inflow of liquid crystal along the multiple inflow paths for liquid crystal extending from the liquid crystal injection port. In this embodiment, the asymmetric forming portion has a first wall portion 51 and a second wall portion 61. The first wall portion 51 is formed from the same material as the first sealing portion 21 and is formed using the same process. This simplifies the manufacturing process for the liquid crystal light control device 100. The second wall portion 52 is formed from the same material as the second sealing portion 22 and is formed using the same process. This simplifies the manufacturing process for the liquid crystal light control device 100.

Example shapes of the first wall portion 51 will be described below. The first wall portion 51 has wall portion 51A and wall portion 51B located on the right side outside the effective dimming area AP, wall portion 51C located near the bottom left corner outside the effective dimming area AP, and wall portion 51D located near the top left corner outside the effective dimming area AP.

The wall portion 51A is a wall portion that is approximately parallel to the third side portion 21C. A liquid crystal injection port 37A is provided between a portion of the wall portion 51A near the lower side and the third side portion 21C. The wall portion 51B is a wall portion that is approximately parallel to the third side portion 21C. A liquid crystal injection port 37B is provided between a portion of the wall portion 51B near the upper side and the third side portion 21C.

The wall portion 51C has a generally C-shape. Specifically, as shown in FIG. 7A, the wall portion 51C has a wall portion 511C that is generally parallel to the second side portion 21B, a wall portion 512C that is generally parallel to the straight portion 21DA, and a wall portion 513C that is generally parallel to the bent portion 21DC. These wall portions 511C, 512C, and 513C are integrally connected to form the wall portion 51C. Liquid crystal injection ports 37C are provided near the boundary between the straight portion 21DA and the bent portion 21DC and near the boundary between the wall portion 512C and the wall portion 513C.

The wall portion 51D has a generally C-shape. Specifically, as shown in FIG. 7B, the wall portion 51D has a wall portion 511D that is generally parallel to the first side portion 21A, a wall portion 512D that is generally parallel to the straight portion 21DB, and a wall portion 513D that is generally parallel to the bent portion 21DD. These wall portions 511D, 512D, and 513D are integrally connected to form the wall portion 51D. Liquid crystal injection ports 37D are provided near the boundary between the straight portion 21DB and the bent portion 21DD, and near the boundary between the wall portion 512D and the wall portion 513D.

In this embodiment, the first wall portion 51 and the second wall portion 52 have substantially the same shape. Therefore, the above description is also applicable to the second wall portion 52. However, this does not exclude the possibility that the first wall portion 51 and the second wall portion 52 may have structural differences.

An example configuration of the second wall portion 52 will be described briefly with reference to Figure 4. The second wall portion 52 has a wall portion 52A having a shape similar to that of wall portion 51A, a wall portion 52B having a shape similar to that of wall portion 51B, a wall portion 52C having a shape similar to that of wall portion 51C, and a wall portion 52D having a shape similar to that of wall portion 51D. In this embodiment, the first seal portion 21 and the second seal portion 22 form a seal portion.

(effect)
Next, the function of the asymmetric forming portion according to this embodiment will be described. The wall portion 51A constituting the asymmetric forming portion imparts asymmetric characteristics to the inflow of liquid crystal in the multiple inflow paths of liquid crystal extending from the liquid crystal injection port 37A. Here, the asymmetry in the inflow of liquid crystal is, for example, a difference in the length (e.g., the shortest distance) of the inflow path from the liquid crystal injection port 37A to a reference position, and the reference position is, for example, approximately the center of the effective dimming area AP set within the first seal portion 21 (the reference position RP described above).

As shown in FIG. 8, liquid crystal LC is injected through the liquid crystal injection port 37A. The wall portion 51A branches the inflow path of the liquid crystal LC within the first liquid crystal injection layer 25 into two, forming two inflow paths starting from the liquid crystal injection port 37A. For example, an inflow path RA having a short length from the liquid crystal injection port 37A to the reference position RP, and an inflow path RB having a long length from the liquid crystal injection port 37A to the reference position RP are formed. Similarly, the wall portion 51B also forms two inflow paths of different lengths through which the liquid crystal LC injected through the liquid crystal injection port 37B flows.

The wall portion 51C also forms two inflow paths for the liquid crystal LC of different lengths. As shown in FIG. 9, the liquid crystal LC is injected through the liquid crystal injection port 37C. The wall portion 51C branches the inflow path of the liquid crystal LC within the first liquid crystal injection layer 25 into two, forming two inflow paths starting from the liquid crystal injection port 37C. For example, an inflow path RC with a short length from the liquid crystal injection port 37C to the reference position RP and an inflow path RD with a long length from the liquid crystal injection port 37C to the reference position RP are formed. Similarly, the wall portion 51D also forms two inflow paths with different lengths along which the liquid crystal LC injected through the liquid crystal injection port 37D flows.

[Example of manufacturing method of liquid crystal light control device]
Next, an example of a manufacturing method for the liquid crystal light control device 100 according to this embodiment will be described. First, the upper substrate 11, middle substrate 12, and lower substrate 13 are prepared. A first electrode E1 is formed on the rear surface 11B of the upper substrate 11. A second electrode E2 is formed on the front surface 12A of the middle substrate 12, and a third electrode E3 is formed on the rear surface 12B. A fourth electrode E4 is formed on the front surface 13A of the lower substrate 13. For example, each electrode is formed by patterning a transparent conductive film with a laser.

Next, a liquid crystal injection port 36 is formed in the lower substrate 13, and a liquid crystal injection port 37 is formed in the middle substrate 12. For example, the liquid crystal injection port 36 and the liquid crystal injection port 37 are formed by laser drilling.

Next, the process of forming the seal portion is carried out. For example, the first seal portion 21 is formed on the back surface 11B of the upper substrate 11. At this time, the first wall portion 51 is also formed at the same time. The second seal portion 22 is formed on the front surface 13A of the lower substrate 13. At this time, the second wall portion 52 is also formed at the same time. For example, the first seal portion 21, the second seal portion 22, the first wall portion 51, and the second wall portion 52 (hereinafter collectively referred to as the first seal portion 21, etc.) are formed by screen printing. The material for the first seal portion 21, etc., is, for example, a thermosetting resin such as an epoxy resin.

Next, silver dots 31 are formed on the back surface 11B of the upper substrate 11, and silver dots 32 are formed on the back surface 12B of the middle substrate 12. For example, the silver dots 31 and 32 are formed by applying conductive carbon.

Next, a spacer dispersion process is performed. For example, glass beads are dispersed on the back surface 11B of the upper substrate 11 and the front surface 12A of the middle substrate 12. In this example, a liquid (e.g., ethanol) containing glass beads with a diameter of 7 μm is dispersed using a spray method or the like.

Next, the upper substrate 11 and middle substrate 12 are bonded together with the first seal 21, and the middle substrate 12 and lower substrate 13 are bonded together with the second seal 22. In this embodiment, because a thermosetting resin is used as the material for the first seal 21 and the second seal 22, the bonding process is performed by applying heat and pressure to the aligned upper substrate 11, middle substrate 12, and lower substrate 13. Through this process, the periphery of the first liquid crystal injection layer 25 is sealed with the first seal 21, and a first wall 51 is disposed within the first liquid crystal injection layer 25. Furthermore, the periphery of the second liquid crystal injection layer 26 is sealed with the second seal 22, and a first wall 52 is disposed within the second liquid crystal injection layer 26.

Next, liquid crystal LC is injected into the first liquid crystal injection layer 25 and the second liquid crystal injection layer 26 through the liquid crystal injection port 36 and the liquid crystal injection port 37. Liquid crystal LC is injected using a liquid crystal droplet LCA containing liquid crystal LC placed on a predetermined jig 60, as shown in the schematic diagram of FIG. 10. Specifically, in this example, the tip of the liquid crystal droplet LCA placed on the jig 60 and subjected to surface tension is brought into contact with the liquid crystal injection port 36 to inject the liquid crystal LC. In this case, the liquid crystal LC is injected using capillary action. Note that the liquid crystal LC is injected into the four liquid crystal injection ports (liquid crystal injection ports 36A to 36D) simultaneously, for example.

The liquid crystal LC injected through the liquid crystal injection port 36 fills not only the second liquid crystal injection layer 26 formed between the lower substrate 13 and the middle substrate 12, but also the first liquid crystal injection layer 25 formed between the middle substrate 12 and the upper substrate 11 via the liquid crystal injection port 37. Here, by injecting the liquid crystal by bringing the tip of the liquid crystal droplet LCA, which is subject to surface tension as described above, into contact with the liquid crystal injection port 36, the liquid crystal is less likely to leak outside the liquid crystal injection port 36, improving the efficiency of liquid crystal LC use. The overlapping of the in-plane positions of the liquid crystal injection ports 36 and 37, particularly their central positions, makes it easier for the liquid crystal LC injected through the liquid crystal injection port 36 to be injected into the innermost liquid crystal layer (first liquid crystal injection layer 25) via the liquid crystal injection port 37, thereby shortening the time required for the liquid crystal injection process.

After the liquid crystal LC has been filled, the liquid crystal injection port 36 is closed with plug material 41, and the liquid crystal injection port 37 is closed with plug material 42. Specifically, in this example, the liquid crystal LC filled is expanded by heating, and the liquid crystal is sucked out through the liquid crystal injection port 36. An adhesive such as an ultraviolet-curable resin, acting as plug materials 41 and 42, is then injected into the gap formed through the liquid crystal injection port 36. As the filled liquid crystal LC then cools, the injected adhesive is drawn into the liquid crystal injection port 37, thereby closing the liquid crystal injection ports 36 and 37 and sealing the liquid crystal LC.

Next, a cable-attached connector is attached to each terminal or electrode to complete the liquid crystal light control device 100. Note that the manufacturing method described above is an example, and the order of some of the steps may be reversed.

[Effects Obtained by This Embodiment]
In the liquid crystal dimming device according to this embodiment, the asymmetrical forming portion forms liquid crystal inflow paths (flow channels) of different lengths in two directions from each liquid crystal inlet. This effectively reduces the wear load on the alignment film near the liquid crystal inlet compared to a configuration with only one inflow path from one liquid crystal inlet (see FIG. 2). This reduces the occurrence of defects such as in-plane unevenness and white spots caused by wear of the alignment film.

Furthermore, when injecting liquid crystal into the first or second liquid crystal injection layer, the liquid crystal tends to flow along the outer edges (first or second sealing portion), so the inflow speed of the liquid crystal LC is generally faster toward the outer edges (sealing side). In this embodiment, the two paths extending from one liquid crystal injection port are configured such that the shorter path toward the center of the effective dimming area (e.g., the inflow paths RA and RC described above) and the longer path toward the outer edges (e.g., the inflow paths RB and RD described above) are configured. In this manner, by providing asymmetry in the lengths of the inflow paths in consideration of the inflow speed of the liquid crystal, a liquid crystal inflow wavefront that is approximately parallel can be achieved. Figures 11A to 11D are schematic diagrams illustrating the process by which the liquid crystal LC (indicated by dots) spreads within the first liquid crystal injection layer 25 (or the second liquid crystal injection layer 26) in this embodiment. Figure 11A shows the state before the liquid crystal LC is injected. The edges of the liquid crystal LC that emerges from each liquid crystal injection port are positioned at approximately the same position in the X direction (Figure 11B), and ultimately the edges of the liquid crystal LC propagating left and right become approximately parallel (Figures 11C and 11D). This reduces the risk of spacers or residual gas agglomerating near the center and the resulting risk of bright spots, as explained in Figure 3, and not only improves the quality of image quality but also improves the strength and reliability of the liquid crystal dimming device. Furthermore, the liquid crystal LC can be dispersed as uniformly as possible in the in-plane direction of the liquid crystal injection layer into which the liquid crystal LC is injected.

Furthermore, with the liquid crystal light control device according to this embodiment, when multiple (e.g., two) liquid crystal layers are provided, only three substrates are required, compared to a configuration in which two substrates are stacked together with a liquid crystal layer filled between the substrates, making it possible to reduce the size of the entire liquid crystal light control device. Furthermore, the manufacturing process can be simplified because the liquid crystal injection process only needs to be performed once, rather than multiple times.

[Application example to imaging device]
The liquid crystal light control device 100 according to this embodiment can be applied to, for example, an imaging device. An example of application of the liquid crystal light control device 100 to an imaging device will be described with reference to Figs.

Figure 12 shows an imaging device 70 and a lens barrel 80 as one of the interchangeable lenses that can be detachably attached to the imaging device 70. The external shapes of the imaging device 70 and lens barrel 80 shown in the figure are merely examples. One type of this embodiment is envisioned as an interchangeable lens video camera or digital still camera.

As shown in the figure, the imaging device 70 is formed with a mount portion 71 for the lens barrel 80, and the lens barrel 80 can be detachably attached to the imaging device 70 via the mount portion 71. The mount portion 71 also has a terminal portion 72. The lens barrel 80 corresponding to the imaging device 70 is provided with electrical contacts that come into contact with the electrical contacts of the terminal portion 72 when attached to the imaging device 70, and this contact state forms a transmission path for various electrical signals between the imaging device 70 and the lens barrel 80.

Figure 13 schematically shows the arrangement of a liquid crystal dimming device 100, an image sensor 73, and a dimming driver 74 that drives the liquid crystal dimming device 100 within the camera body of the image capture device 70. The dimming driver 74 provides liquid crystal drive signals SP1 and SP2 to each liquid crystal layer in the liquid crystal dimming device 100 to control the transmittance of each liquid crystal layer. The image sensor 73 is configured, for example, as a CCD (Charge Coupled Device) type or a CMOS (Complementary Metal Oxide Semiconductor) type. A lens system 81 consisting of optical components such as multiple lenses, including a zoom lens and a focus lens, is provided on the lens barrel 80 side. In the configuration example of Figure 13, when the lens barrel 80 is attached to the image capture device 70, incident light through the lens system 81 is dimmed by the liquid crystal dimming device 100 on the image capture device 70 side and received by the image capture device 73.

FIG. 14A shows an example in which a lens system 81, a liquid crystal light control device 100, and a light control driver 74 are arranged on the lens barrel 80 side, and an imaging element 73 is arranged on the main body side of the imaging device 70.
In this case as well, when the lens barrel 80 is attached to the imaging device 70 , the incident light passing through the lens system 81 is modulated by the liquid crystal light control device 100 and received by the imaging element 73 .

Figure 14B shows an example in which the lens system 81 and liquid crystal dimming device 100 are arranged on the lens barrel 80 side, and the image sensor 73 and dimming driver 74 are arranged on the main body side of the imaging device 70. In this example, when the lens barrel 80 is attached to the imaging device 70, the liquid crystal drive signals SP1 and SP2 are supplied to the liquid crystal dimming device 100 from the dimming driver 74.

Figure 15 shows an image capture device 70A that is not a lens-interchangeable type, but is an integrated lens type, and this type of integrated lens type image capture device 70A is also one type of this embodiment. Naturally, in this case, the lens system 81, liquid crystal dimming device 100, image sensor 73, and dimming drive unit 74 are all located within the main body of the image capture device 70A.

Figure 16 shows an example in which the liquid crystal dimming device 100 and dimming drive unit 74 are built into an adapter device 90. As shown schematically in Figure 16, the adapter device 90 is disposed between the imaging device 70 and the lens barrel 80. The adapter device 90 is detachable from both the imaging device 70 and the lens barrel 80. In this way, the present disclosure can also be realized as an adapter device 90 having a liquid crystal dimming device 100 as the liquid crystal dimming unit. Note that in the configuration example shown in Figure 16, the dimming drive unit 74 may be located in the lens barrel 80 or the imaging device 70.

<Modification>
Although one embodiment of the present disclosure has been specifically described above, the content of the present disclosure is not limited to the above-described embodiment, and various modifications based on the technical ideas of the present disclosure are possible.

The shape of the wall portion of the asymmetric forming portion can be changed as appropriate. For example, it may have the shape of the wall portion (wall portion 51E) shown in FIG. 17. Wall portion 51E has, for example, a wall portion 511E that is approximately parallel to third side portion 21C, a wall portion 512E that is located more inward than wall portion 511E and is approximately parallel to third side portion 21C, and a connecting portion 513E that is approximately parallel to first side portion 21A and connects wall portion 511E and wall portion 512E. A liquid crystal injection port 37A is provided between connecting portion 513E and third side portion 21C (approximately the center of wall portion 51E in the Y direction).

The wall portion 51E forms inflow channels RE and RF as inflow channels for the liquid crystal LC. In this example, the width WA (length in the X direction) of the inflow channel RE is different from the width WB (length in the X direction) of the inflow channel RF. For example, the width WA is set larger than the width WB. In this way, the asymmetry regarding the inflow of the liquid crystal may be due to the difference in width between the inflow channels. The difference in width WA and width WB results in a difference in the flow velocity of the liquid crystal LC flowing through the inflow channel RE and the flow velocity of the liquid crystal LC flowing through the inflow channel RF. Specifically, the flow velocity of the liquid crystal LC flowing through the inflow channel RF is faster than the flow velocity of the liquid crystal LC flowing through the inflow channel RE. In this way, from another perspective, the asymmetry regarding the inflow of the liquid crystal may be due to a difference in the flow velocity of the liquid crystal flowing through the inflow channels. Furthermore, the difference in width WA and width WB results in a difference in the flow rate of the liquid crystal LC flowing through the inflow channel RE (e.g., the flow rate of the liquid crystal LC flowing per unit time) and the flow rate of the liquid crystal LC flowing through the inflow channel RF. Specifically, the flow rate of the liquid crystal LC flowing through the inflow path RE is greater than the flow rate of the liquid crystal LC flowing through the inflow path RF. In this way, from another perspective, the asymmetry regarding the inflow of liquid crystal may be a difference in the flow rate of the liquid crystal flowing through the inflow paths.

In the embodiment described above, the liquid crystal was injected into the first and second liquid crystal injection layers from the same direction (the lower substrate side). However, the liquid crystal may be injected into the first and second liquid crystal injection layers from different directions. For example, as shown in FIG. 18 , a liquid crystal injection port 37 is provided in the upper substrate 11. Then, liquid crystal is injected into the first liquid crystal injection layer 25 through the liquid crystal injection port 37 from the front surface 11A side of the upper substrate 11 (upward (an example of a first direction)). As with the embodiment, liquid crystal is injected into the second liquid crystal injection layer 26 through the liquid crystal injection port 36 from the rear surface 13B side of the lower substrate 13 (downward (an example of a second direction)). This configuration enables the liquid crystal to be dispersed more uniformly in the first liquid crystal injection layer 25 than a configuration in which liquid crystal is injected through a liquid crystal injection port between layers.

In the embodiment described above, there were two liquid crystal layers, a first liquid crystal layer and a second liquid crystal layer, but the number may be one or three or more. The number of sealing portions may be other than two. Furthermore, while two liquid crystal inflow paths were formed by the wall portion, which is an example of an asymmetric forming portion, three or more inflow paths may be formed. Furthermore, in the embodiment described above, an example configuration was described in which the asymmetric forming portion included eight wall portions (four wall portions of the first wall portion 51 and four wall portions of the second wall portion 52). However, some of the eight wall portions may be asymmetric forming portions, or the number of wall portions may be other than eight. The shape of the wall portions may also be changed as appropriate. Furthermore, the asymmetric forming portion may be a recess provided in the middle substrate or the lower substrate rather than a wall portion, and such a recess may be used to create asymmetry in the inflow of liquid crystal. The liquid crystal dimming device may be applicable to applications other than ND filters.

The liquid crystal light control device described in the above embodiment may have other components. For example, the liquid crystal light control device may have a pair of polarizing plates provided on the front side of the upper substrate and the back side of the lower substrate.

The configurations, methods, processes, shapes, materials, and numerical values, etc., listed in the embodiment and modifications are merely examples, and different configurations, methods, processes, shapes, materials, and numerical values, etc., may be used as needed. Furthermore, unless otherwise specified, the materials exemplified in the embodiment and modifications can be used alone or in combination of two or more types. Furthermore, the components described in the embodiment and modifications can be combined as appropriate.

Please note that the effects described in this specification are merely examples and are not limiting, and other effects may also be present.

The present disclosure may also have the following configurations.
(1)
a liquid crystal injection port for injecting liquid crystal into the liquid crystal injection layer surrounded by the sealing portion;
an asymmetry forming portion for providing asymmetry regarding the inflow of the liquid crystal in a plurality of inflow paths extending from the liquid crystal inlet;
A liquid crystal dimming device having the same.
(2)
The asymmetry regarding the inflow of the liquid crystal is a difference in the length of the inflow path from the liquid crystal injection port to the reference position.
The liquid crystal light control device according to (1).
(3)
the reference position is approximately the center of an effective light control area set within the seal portion;
A liquid crystal dimming device according to (2).
(4)
The asymmetry in the inflow of the liquid crystal is a difference in the flow speed of the liquid crystal flowing through the inflow path.
The liquid crystal light control device according to (1).
(5)
The asymmetry regarding the inflow of the liquid crystal is a difference in width between the inflow paths.
The liquid crystal light control device according to (1).
(6)
The asymmetry regarding the inflow of the liquid crystal is a difference in the flow rate of the liquid crystal flowing through the inflow path.
The liquid crystal light control device according to (1).
(7)
a plurality of the liquid crystal injection layers stacked one on top of the other;
the liquid crystal injection ports for the liquid crystal injection layers are arranged so as to overlap each other along the stacking direction of the liquid crystal injection layers;
A liquid crystal light control device according to any one of (1) to (6).
(8)
a liquid crystal injection port is formed through which liquid crystal is injected from a first direction into the liquid crystal injection layer disposed below;
a liquid crystal injection port is formed through which liquid crystal is injected from a second direction opposite to the first direction into the liquid crystal injection layer disposed on the upper side;
(7) A liquid crystal light control device according to (7).
(9)
The asymmetric forming portion is a wall portion that is substantially parallel to the sealing portion.
A liquid crystal light control device according to any one of (1) to (8).
(10)
The asymmetric forming portion has a shape in which a plurality of wall portions substantially parallel to the sealing portion are connected by connecting portions.
A liquid crystal light control device according to any one of (1) to (9).
(11)
the asymmetric formation portion forms two inflow paths originating from the liquid crystal injection port;
A liquid crystal light control device according to any one of (1) to (10).
(12)
The asymmetric forming portion is formed of the same material as the sealing portion.
A liquid crystal light control device according to any one of (1) to (11).
(13)
The liquid crystal injection port is sealed with a plug.
A liquid crystal light control device according to any one of (1) to (12).
(14)
An imaging element;
A liquid crystal dimming unit,
a light control driver that drives the liquid crystal light control unit;
and
The liquid crystal light control unit
a liquid crystal injection port for injecting liquid crystal into the liquid crystal injection layer surrounded by the sealing portion;
an asymmetry forming portion for providing asymmetry regarding the inflow of the liquid crystal in a plurality of inflow paths extending from the liquid crystal inlet.
(15)
a liquid crystal injection port for injecting liquid crystal into the liquid crystal injection layer surrounded by the sealing portion;
an asymmetry forming portion for providing asymmetry regarding the inflow of the liquid crystal in a plurality of inflow paths extending from the liquid crystal inlet;
An adapter device having:

11: Upper substrate 12: Middle substrate 13: Lower substrate 21: First sealing portion 22: Second sealing portion 36A, 36B, 36C, 36D: Liquid crystal injection port 37A, 37B, 37C, 37D: Liquid crystal injection port 51: First wall portion 51A, 51B, 51C, 51D: Wall portion 52: Second wall portion 52A, 52B, 52C, 52D: Wall portion 73: Image pickup element 100: Liquid crystal dimming device AP: Effective dimming area LC: Liquid crystal RA, RB, RC, RD, RE, RF: Inflow path RP: Reference position

Claims (13)

a liquid crystal injection port for injecting liquid crystal into the liquid crystal injection layer surrounded by the sealing portion;
a wall portion for providing asymmetry regarding the inflow of the liquid crystal in a plurality of inflow paths extending from the liquid crystal inlet;
and
the sealing portion has a side portion along a propagation direction in which the liquid crystal propagates from the liquid crystal injection port toward approximately the center of an effective dimming area set within the sealing portion,
the wall portion is provided independently of the sealing portion within the liquid crystal injection layer surrounded by the sealing portion,
Further, the wall portion has a first end and a second end,
the first end is provided at a position closer to the approximate center of the effective light control area than the second end, and the second end is provided at a position closer to the side portion than the first end ,
the liquid crystal injection port is provided at a position closer to the first end than to the second end.
LCD dimmer. the asymmetry in the inflow of the liquid crystal is a difference in the length of the inflow path from the liquid crystal injection port to approximately the center of the effective dimming area;
The liquid crystal light control device according to claim 1 . The asymmetry in the inflow of the liquid crystal is a difference in the flow speed of the liquid crystal flowing through the inflow path.
The liquid crystal light control device according to claim 1 . The asymmetry regarding the inflow of the liquid crystal is a difference in width between the inflow paths.
The liquid crystal light control device according to claim 1 . a plurality of the liquid crystal injection layers stacked one on top of the other;
the liquid crystal injection ports for the liquid crystal injection layers are arranged so as to overlap each other along the stacking direction of the liquid crystal injection layers;
The liquid crystal light control device according to claim 1 . a liquid crystal injection port is formed through which liquid crystal is injected from a first direction into the liquid crystal injection layer disposed below;
a liquid crystal injection port is formed through which liquid crystal is injected from a second direction opposite to the first direction into the liquid crystal injection layer disposed on the upper side;
The liquid crystal light control device according to claim 5 . The wall portion is a wall portion that is substantially parallel to the seal portion.
The liquid crystal light control device according to claim 1 . The wall portion has a shape in which a plurality of wall portions substantially parallel to the sealing portion are connected by connecting portions.
The liquid crystal light control device according to claim 1 . the wall portion forms two inflow paths originating from the liquid crystal injection port;
The liquid crystal light control device according to claim 1 . The wall portion is formed of the same material as the sealing portion.
The liquid crystal light control device according to claim 1 . The liquid crystal injection port is sealed with a plug.
The liquid crystal light control device according to claim 1 . An imaging element;
A liquid crystal dimming unit,
a light control driver that drives the liquid crystal light control unit;
and
The liquid crystal light control unit
a liquid crystal injection port for injecting liquid crystal into the liquid crystal injection layer surrounded by the sealing portion;
a wall portion for providing asymmetry regarding the inflow of the liquid crystal in a plurality of inflow paths extending from the liquid crystal inlet;
and
the sealing portion has a side portion along a propagation direction in which the liquid crystal propagates from the liquid crystal injection port toward approximately the center of an effective dimming area set within the sealing portion,
the wall portion is provided independently of the sealing portion within the liquid crystal injection layer surrounded by the sealing portion,
Further, the wall portion has a first end and a second end,
the first end is provided at a position closer to the approximate center of the effective light control area than the second end, and the second end is provided at a position closer to the side portion than the first end ,
The liquid crystal injection port is provided at a position closer to the first end than to the second end. a liquid crystal injection port for injecting liquid crystal into the liquid crystal injection layer surrounded by the sealing portion;
a wall portion for providing asymmetry regarding the inflow of the liquid crystal in a plurality of inflow paths extending from the liquid crystal inlet;
and
the sealing portion has a side portion along a propagation direction in which the liquid crystal propagates from the liquid crystal injection port toward approximately the center of an effective dimming area set within the sealing portion,
the wall portion is provided independently of the sealing portion within the liquid crystal injection layer surrounded by the sealing portion,
Further, the wall portion has a first end and a second end,
the first end is provided at a position closer to the approximate center of the effective light control area than the second end, and the second end is provided at a position closer to the side portion than the first end ,
The liquid crystal injection port is provided at a position closer to the first end than to the second end.