阅读说明：本技术 车辆用灯具 (Vehicle lamp ) 是由 都甲康夫 于 2019-07-24 设计创作，主要内容包括：本发明提供一种车辆用灯具,该车辆用灯具具有新型结构。该车辆用灯具包括：光源；配置在从所述光源射出的光的光路上并包含液晶层以及夹持该液晶层的一对夹持基板的液晶元件；以及配置在透过所述液晶元件的光的光路上的投影光学系统,所述液晶元件的一对夹持基板中的一方包含第1透明基板和配置在所述第1透明基板上的公共电极,所述液晶元件的一对夹持基板中的另一方包含：第2透明基板；配置在所述第2透明基板上的多个配线电极；以覆盖所述多个配线电极的方式配置在所述第2透明基板上的绝缘层；配置在所述绝缘层上的多个分段电极；以及贯穿所述绝缘层并对所述多个配线电极各自与所述多个分段电极各自进行电连接的多个连接电极。(The invention provides a vehicle lamp having a novel structure. The vehicular lamp includes: a light source; a liquid crystal element which is arranged on an optical path of light emitted from the light source and includes a liquid crystal layer and a pair of sandwiching substrates sandwiching the liquid crystal layer; and a projection optical system disposed on an optical path of light transmitted through the liquid crystal element, wherein one of a pair of sandwiching substrates of the liquid crystal element includes a 1 st transparent substrate and a common electrode disposed on the 1 st transparent substrate, and the other of the pair of sandwiching substrates of the liquid crystal element includes: a 2 nd transparent substrate; a plurality of wiring electrodes disposed on the 2 nd transparent substrate; an insulating layer disposed on the 2 nd transparent substrate so as to cover the plurality of wiring electrodes; a plurality of segment electrodes disposed on the insulating layer; and a plurality of connection electrodes penetrating the insulating layer and electrically connecting each of the plurality of wiring electrodes and each of the plurality of segment electrodes.)

1. A lamp for a vehicle, comprising:

a light source;

a liquid crystal element disposed on an optical path of light emitted from the light source, the liquid crystal element including a liquid crystal layer and a pair of sandwiching substrates sandwiching the liquid crystal layer; and

a projection optical system disposed on an optical path of the light transmitted through the liquid crystal element,

one of the pair of sandwiching substrates of the liquid crystal element includes:

a 1 st transparent substrate; and

a common electrode disposed on the 1 st transparent substrate,

the other of the pair of sandwiching substrates of the liquid crystal element includes:

a 2 nd transparent substrate;

a plurality of wiring electrodes disposed on the 2 nd transparent substrate;

an insulating layer disposed on the 2 nd transparent substrate so as to cover the plurality of wiring electrodes;

a plurality of segment electrodes disposed on the insulating layer; and

a plurality of connection electrodes that penetrate the insulating layer and electrically connect each of the plurality of wiring electrodes and each of the plurality of segment electrodes.

2. The vehicular lamp according to claim 1, wherein,

the plurality of segment electrodes are arranged in a matrix.

3. The vehicular lamp according to claim 2, wherein,

the plurality of segment electrodes include 1 st group of segment electrodes arranged in the 1 st direction in a plan view,

the width of each of the 1 st group of segment electrodes in the 1 st direction becomes gradually narrower from one end toward the center, and becomes gradually wider from the center toward the other end.

4. The vehicular lamp according to claim 3, wherein,

the plurality of segment electrodes include 2 nd component segment electrodes arranged in a 2 nd direction perpendicular to the 1 st direction in a plan view,

the width of each of the 2 nd group of segment electrodes in the 2 nd direction becomes gradually narrower from one end toward the center, and becomes gradually wider from the center toward the other end.

5. The vehicular lamp according to claim 1, wherein,

the shapes of the plurality of segment electrodes are different from each other in a plan view.

6. The vehicular lamp according to any one of claims 1 to 5,

the plurality of wiring electrodes are configured to overlap, in a plan view, 80% or more of a total area defined by gaps between the respective segment electrodes of the plurality of segment electrodes.

Technical Field

The present invention relates to a vehicle lamp including a liquid crystal element.

Background

In recent years, attention has been paid to a technology (referred to as ADB, adaptive driving beam, or the like) for controlling a light distribution shape in real time in accordance with the situation ahead, that is, the presence or absence of an oncoming vehicle, a leading vehicle, or the like, and the position thereof. A headlamp system (referred to as an AFS, adaptive front-lighting system, or the like) that adjusts the light distribution in the traveling direction in accordance with the steering angle of the steering wheel is becoming widespread. As a light distribution control element of the ADB or the AFS, a liquid crystal element can be used (for example, patent document 1).

Patent document 2 discloses a vehicle headlamp configured to include: a light emitting portion 11 composed of at least one LED11 a; and a light shielding portion 12 for cutting off a part of light emitted forward from the light emitting portion to form a cut-off line suitable for a light distribution pattern for a vehicle headlamp, wherein the light shielding portion 12 is composed of an electro-optical element having a light adjusting function and a control portion 14 for performing light adjusting control on the electro-optical element, and the shape of the light distribution pattern is changed by selectively adjusting the light adjusting portion by performing electrical switching control on the electro-optical element by the control portion. As the electro-optical element, for example, a liquid crystal element can be used.

In the vehicle lamp described above, the electro-optical element such as the liquid crystal element is configured to have a plurality of pixel electrodes in order to realize selective light control. These pixel electrodes are separated from each other so that voltages can be applied independently, respectively, with a gap for electrical insulation provided therebetween. In this case, the gap between the pixel electrodes is, for example, about 10 μm, although it depends on the forming accuracy. In addition, in the case where three or more pixel electrodes are provided in a column, a wiring portion for supplying a voltage to each pixel electrode in an intermediate column needs to be inserted between the pixel electrodes, and thus a gap between the pixel electrodes becomes larger. The gap between the pixel electrodes is a portion that does not contribute to image formation, and is a factor causing dark lines to be generated in the light distribution pattern. In the vehicle lamp, since an image (an image corresponding to the light distribution pattern) formed by the electro-optical element is enlarged by a lens or the like and projected forward of the vehicle, the dark line as described above is also enlarged and easily visually recognized, and thus there is a problem that the beauty of the light distribution pattern is deteriorated. In this case, although a solution can be considered such that the gap between the pixel electrodes is further narrowed, this is not preferable because the manufacturing cost is increased and a defect such as a short circuit between the pixel electrodes is likely to occur. In addition, a solution can be considered in which the width of the wiring portion passing between the pixel electrodes is made smaller, but in this case, the resistance value of the wiring portion is increased, it is difficult to apply a sufficient voltage necessary for the pixel electrodes, and the probability of occurrence of disconnection due to thinning is also increased, which is not preferable. Such a problem is not limited to the vehicle lamp, but is also applicable to a general lighting device that controls a light distribution pattern using a liquid crystal element or the like.

Disclosure of Invention

Problems to be solved by the invention

The invention mainly aims to provide a vehicle lamp with a novel structure.

Means for solving the problems

According to a main aspect of the present invention, there is provided a lamp for a vehicle, comprising: a light source; a liquid crystal element disposed on an optical path of light emitted from the light source, the liquid crystal element including a liquid crystal layer and a pair of sandwiching substrates sandwiching the liquid crystal layer; and a projection optical system disposed on an optical path of light transmitted through the liquid crystal element, one of the pair of sandwiching substrates of the liquid crystal element including: a 1 st transparent substrate; and a common electrode disposed on the 1 st transparent substrate, wherein the other of the pair of sandwiching substrates of the liquid crystal element includes: a 2 nd transparent substrate; a plurality of wiring electrodes disposed on the 2 nd transparent substrate; an insulating layer disposed on the 2 nd transparent substrate so as to cover the plurality of wiring electrodes; a plurality of segment electrodes disposed on the insulating layer; and a plurality of connection electrodes that penetrate the insulating layer and electrically connect each of the plurality of wiring electrodes and each of the plurality of segment electrodes.

The plurality of segment electrodes may be arranged in a matrix.

In this case, it is preferable that the plurality of segment electrodes include 1 st group of segment electrodes arranged in the 1 st direction in a plan view, and a width of each of the 1 st group of segment electrodes in the 1 st direction gradually becomes narrower from one end toward the center and gradually becomes wider from the center toward the other end.

Preferably, the plurality of segment electrodes include a 2 nd group of segment electrodes arranged in a 2 nd direction perpendicular to the 1 st direction in a plan view, and a width of each of the 2 nd group of segment electrodes in the 2 nd direction gradually becomes narrower from one end toward a center and gradually becomes wider from the center toward the other end.

Alternatively, the plurality of segment electrodes may have different shapes from each other in a plan view.

Preferably, the plurality of wiring electrodes are arranged so as to overlap, in a plan view, 80% or more of a total area defined by gaps between the respective segment electrodes of the plurality of segment electrodes.

Effects of the invention

A vehicle lamp having a novel structure can be provided.

Drawings

Fig. 1 is a diagram showing a configuration of a vehicle headlamp system according to an embodiment.

Fig. 2 (a) and 2 (B) are schematic cross-sectional views showing the structure of the liquid crystal element.

Fig. 3 is a schematic plan view showing the structure of the liquid crystal element.

Fig. 4 is a diagram for explaining a relationship between the shape of the connection portion of each pixel electrode and the orientation processing direction.

Fig. 5 (a) to 5 (C) are diagrams for explaining the relationship between each connection portion and the orientation processing direction.

Fig. 6 is a graph showing transmittance characteristics of each sample of the liquid crystal element.

Fig. 7 is a graph showing the change in chromaticity of each sample.

Fig. 8 is a plan view for explaining a modified example of the common electrode.

Fig. 9 is a plan view for explaining a modified embodiment of the pixel electrode and the inter-pixel electrode.

Fig. 10 is a plan view for explaining a modified embodiment of the pixel electrode.

Fig. 11 and 12 are plan views for explaining another modified embodiment of the pixel electrode.

Fig. 13 is a plan view for explaining another modified embodiment of the pixel electrode.

Description of the symbols

1: light source

2: camera head

3: control device

4: liquid crystal driving device

5: liquid crystal element

6a, 6 b: polarizing plate

7: projection lens

11: upper substrate

12: lower substrate

13: common electrode

14. 14a, 14b, 14 c: pixel electrode

15. 15a, 15b, 15 c: inter-pixel electrode

16. 16a, 16b, 16 c: wiring part

17: insulating layer

18: liquid crystal layer

19: through hole

20. 20a, 20b, 20 c: connecting part

21: direction of orientation treatment

22: side chain of alignment film

23: opening part

Detailed Description

Fig. 1 is a diagram showing a configuration of a vehicle headlamp system according to an embodiment. The vehicle headlamp system shown in fig. 1 includes a light source 1, a camera 2, a control device 3, a liquid crystal driving device 4, a liquid crystal element 5, a pair of polarizing plates 6a and 6b, and a projection lens 7. The vehicle headlamp system has the following purposes: the position of a preceding vehicle, a pedestrian, or the like present around the host vehicle is detected from the image captured by the camera 2, a fixed range including the position of the preceding vehicle or the like is set as a non-irradiation range, and the other ranges are set as light irradiation ranges, and selective light irradiation is performed.

The light source 1 includes a white light LED configured by combining a yellow phosphor and a light emitting element (LED) that emits, for example, blue light. The light source 1 includes, for example, a plurality of white light LEDs arranged in a matrix. As the light source 1, in addition to LEDs, light sources generally used in vehicle lamp units, such as a laser, a bulb, and a discharge lamp, can be used. The lighting and off states of the light source 1 are controlled by the control device 3. Light emitted from the light source 1 is incident on the liquid crystal element (liquid crystal panel) 5 via the polarizing plate 6 a. In addition, another optical system (for example, a lens or a mirror, and a combination thereof) may be present on the path from the light source 1 to the liquid crystal element 5.

The camera 2 captures an image of the front of the host vehicle and outputs the image (information), and the camera 2 is disposed at a predetermined position (for example, an upper portion inside the front windshield) in the host vehicle. In addition, when a camera for another use (for example, an automatic brake system) is provided in the host vehicle, the camera may be shared.

The control device 3 detects the position of the vehicle ahead by performing image processing based on the image obtained by the camera 2 that captures the image of the vehicle ahead, sets a light distribution pattern in which the detected position of the vehicle ahead or the like is a non-irradiation range and the other region is a light irradiation range, generates a control signal for forming an image corresponding to the light distribution pattern, and supplies the control signal to the liquid crystal driving device 4. The control device 3 is realized by executing a predetermined operation program on a computer system having, for example, a CPU, a ROM, a RAM, or the like.

The liquid crystal driving device 4 supplies a driving voltage to the liquid crystal element 5 in accordance with a control signal supplied from the control device 3, thereby independently controlling the alignment state of the liquid crystal layer in each pixel region of the liquid crystal element 5.

The liquid crystal element 5 has, for example, a plurality of pixel regions (light modulation regions) which can be independently controlled, and the transmittance of each pixel region is variably set in accordance with the magnitude of the voltage applied to the liquid crystal layer by the liquid crystal driving device 4. By irradiating the liquid crystal element 5 with light from the light source 1, an image having a brightness corresponding to the light irradiation range and the non-irradiation range is formed. For example, the liquid crystal element 5 has a vertical alignment type liquid crystal layer, is disposed between a pair of polarizing plates 6a and 6b arranged in cross-nicol, and is in a state where light transmittance is extremely low (light-shielded state) when a voltage applied to the liquid crystal layer is no (or a voltage equal to or less than a threshold), and is in a state where light transmittance is relatively high (transmissive state) when a voltage is applied to the liquid crystal layer.

The pair of polarizing plates 6a and 6b are disposed so as to face each other with the liquid crystal element 5 interposed therebetween, for example, with their polarization axes substantially perpendicular to each other. In this embodiment, a normally-off mode is assumed as an operation mode in which light is blocked (transmittance is extremely low) when no voltage is applied to the liquid crystal layer. As the polarizing plates 6a and 6b, for example, absorption-type polarizing plates made of a general organic material (iodine-based or dye-based) can be used. When importance is attached to heat resistance, a wire grid type polarizing plate is also preferably used. The wire grid type polarizing plate is a polarizing plate in which extremely thin wires made of metal such as aluminum are arranged. Further, the absorption-type polarizing plate and the wire-grid-type polarizing plate may be used in a stacked manner.

The projection lens 7 projects an image formed by light transmitted through the liquid crystal element 5 (an image having a light and shade corresponding to the light irradiation range and the non-irradiation range) forward of the vehicle by expanding the image to be a light distribution for the headlight, and the projection lens 7 is a lens designed appropriately. In this embodiment, an inverted projection type projector lens is used.

Fig. 2 (a) and 2 (B) are schematic cross-sectional views showing the structure of the liquid crystal element. Fig. 3 is a schematic plan view showing the structure of the liquid crystal element. The sectional view shown in fig. 2 (a) corresponds to a partial section taken along line a-a shown in fig. 3, and the sectional view shown in fig. 2 (B) corresponds to a partial section taken along line B-B shown in fig. 3. The liquid crystal element 5 includes an upper substrate (1 st substrate) 11 and a lower substrate (2 nd substrate) 12 which are arranged to face each other, a common electrode (counter electrode) 13 provided on the upper substrate 11, a plurality of pixel electrodes 14 provided on the lower substrate 12, a plurality of inter-pixel electrodes 15, a plurality of wiring portions 16, an insulating layer 17, and a liquid crystal layer 18 arranged between the upper substrate 11 and the lower substrate 12. For convenience of explanation, alignment films for regulating the alignment state of the liquid crystal layer 18 are suitably provided on the upper substrate 11 and the lower substrate 12, respectively.

The upper substrate 11 and the lower substrate 12 are rectangular substrates in plan view, and are arranged to face each other. As each substrate, a transparent substrate such as a glass substrate or a plastic substrate can be used. A plurality of spacers are equally distributed between the upper substrate 11 and the lower substrate 12, for example, and the substrate gap is maintained at a desired size (for example, about several μm) by the spacers.

The common electrode 13 is provided on one surface side of the upper substrate 11. The common electrode 13 is integrally provided so as to face each pixel electrode 14 provided on the lower substrate 12. The common electrode 13 is formed by appropriately forming a wiring pattern (patterning) on a transparent conductive film such as Indium Tin Oxide (ITO).

The plurality of pixel electrodes 14 are provided on the upper side of the insulating layer 17 on one surface side of the lower substrate 12. These pixel electrodes 14 are formed by appropriately forming a wiring pattern on a transparent conductive film such as Indium Tin Oxide (ITO). As shown in fig. 4, each pixel electrode 14 has an outer edge shape having a substantially square shape in plan view, for example, and is arranged in a matrix in the x direction and the y direction. A gap is provided between the pixel electrodes 14. The regions where the common electrode 13 overlaps the pixel electrodes 14 constitute the pixel regions (light modulation regions).

The plurality of inter-pixel electrodes 15 are provided on the lower layer side of the insulating layer 17 on one surface side of the lower substrate 12. These inter-pixel electrodes 15 are formed by appropriately forming a wiring pattern on a transparent conductive film such as Indium Tin Oxide (ITO). As shown in fig. 4, each inter-pixel electrode 15 has an outer edge shape, for example, a rectangular shape in a plan view, and is arranged so as to overlap with a gap between two pixel electrodes 14 adjacent to each other in the x direction in the drawing.

The plurality of wiring portions 16 are provided on the lower layer side of the insulating layer 17 on one surface side of the lower substrate 12. These wiring portions 16 are formed by forming a wiring pattern appropriately on a transparent conductive film such as Indium Tin Oxide (ITO). Each wiring section 16 is used to supply a voltage from the liquid crystal driving device 4 to each pixel electrode 14.

The insulating layer 17 is provided on the upper side of each inter-pixel electrode 15 and each wiring portion 16 on the one surface side of the lower substrate 12 so as to cover each inter-pixel electrode 15 and each wiring portion 16. The insulating layer 17 is for example SiO ₂The film or SiON film can be formed by a gas phase process such as sputtering or a solution process.

The liquid crystal layer 18 is disposed between the upper substrate 11 and the lower substrate 12. In the present embodiment, the liquid crystal layer 18 is formed using a nematic liquid crystal material having negative dielectric anisotropy Δ ∈ and containing a chiral agent and having fluidity. The liquid crystal layer 18 of the present embodiment is set as follows: the alignment direction of the liquid crystal molecules in the absence of voltage is inclined in one direction, and the liquid crystal molecules are aligned substantially perpendicularly to the substrate surfaces with a pretilt angle in a range of, for example, 88 ° or more and less than 90 °.

As described above, the alignment films are provided on the one surface side of the upper substrate 11 and the one surface side of the lower substrate 12, respectively. As each alignment film, a vertical alignment film is used which restricts the alignment state of liquid crystal molecules of the liquid crystal layer 18 to vertical alignment. Each alignment film is subjected to uniaxial alignment treatment such as rubbing treatment, and has a uniaxial alignment regulating force for regulating the alignment of liquid crystal molecules of the liquid crystal layer 18 in this direction. The directions of the alignment treatment applied to the respective alignment films are set to be different from each other (antiparallel), for example.

The liquid crystal element 5 of the present embodiment has tens to hundreds of pixel regions, which are arranged in a matrix, and the pixel regions are defined as regions where the common electrode 13 and the pixel electrodes 14 overlap each other in a plan view. In the present embodiment, the shape of each pixel region is, for example, a square shape, but the shape of each pixel region can be set arbitrarily, and for example, a rectangular shape and a square shape are mixed. The common electrode 13, the pixel electrodes 14, and the inter-pixel electrodes 15 are connected to the liquid crystal driving device 4 via the wiring portions 16 and the like, and are statically driven.

Referring again to fig. 3, the structures of the pixel electrodes 14, the inter-pixel electrodes 15, and the wiring portions 16 will be described in detail. In the present embodiment, the pixel electrodes 14 are arranged in three rows in the y direction, and an arbitrary number of the pixel electrodes are arranged in the x direction. Here, the 1 st column from the top in the drawing is referred to as a pixel electrode 14a, the 2 nd column is referred to as a pixel electrode 14b, and the 3 rd column is referred to as a pixel electrode 14c for each pixel electrode 14. Further, as for the inter-pixel electrode 15, the inter-pixel electrode corresponding to the 1 st column pixel electrode 14a is referred to as an inter-pixel electrode 15a, the inter-pixel electrode corresponding to the 2 nd column pixel electrode 14b is referred to as an inter-pixel electrode 15b, and the inter-pixel electrode corresponding to the 3 rd column pixel electrode 14c is referred to as an inter-pixel electrode 15 c. In addition, in the wiring section 16, the wiring section corresponding to the 1 st column pixel electrode 14a and the inter-pixel electrode 15a is referred to as a wiring section 16a, the wiring section corresponding to the 2 nd column pixel electrode 14b and the inter-pixel electrode 15b is referred to as a wiring section 16b, and the wiring section associated with the 3 rd column pixel electrode 14c and the inter-pixel electrode 15c is referred to as a wiring section 16 c.

Each pixel electrode 14a is connected to the lower-layer inter-pixel electrode 15a and the wiring portion 16a via a through hole 19 provided in the insulating layer 17. Thereby, the pixel electrode 14a, the inter-pixel electrode 15a, and the wiring portion 16a have the same potential. Each through hole 19 has an outer edge shape having a substantially triangular shape in plan view as shown in fig. 3, and is provided so as to correspond to one of four corners (upper left corner in the drawing) of each pixel electrode 14a in plan view. Each pixel electrode 14a has a connection portion 20a formed along the wall surface of the through hole 19. The connection portion 20a is in contact with the lower inter-pixel electrode 15a and the portion of the wiring portion 16a exposed at the bottom of the through hole 19.

Similarly, each pixel electrode 14b has a connection portion 20b formed along the wall surface of the through hole 19, and is connected to the inter-pixel electrode 15b and the wiring portion 16b on the lower layer side. Thereby, the pixel electrode 14b, the inter-pixel electrode 15b, and the wiring portion 16b have the same potential. Similarly, each pixel electrode 14c has a connection portion 20c formed along the wall surface of the through hole 19, and is connected to the inter-pixel electrode 15c and the wiring portion 16c on the lower layer side. Thereby, the pixel electrode 14c, the inter-pixel electrode 15c, and the wiring portion 16c have the same potential.

Each inter-pixel electrode 15a is disposed so as to fill the gap between two adjacent pixel electrodes 14a in the x direction in a plan view. In the present embodiment, each of the inter-pixel electrodes 15a is disposed so that the left outer edge thereof and the right outer edge of the pixel electrode 14a disposed on the left side thereof are substantially at the same position in the vertical direction in plan view.

Each inter-pixel electrode 15a is disposed so that a partial region (1 st region) 115a partially overlaps a partial region in the vicinity of the left outer edge of the pixel electrode 14a disposed on the right side thereof, and the partial region 115a is located inward of the right edge thereof in plan view. These local regions 115a prevent the generation of an oblique electric field in the vicinity of the outer edge on the left side in the figure of the pixel electrode 14a, and have an effect of suppressing the generation of a dark region. From this point of view, it is preferable to increase the y-direction length of each local region 115a as much as possible, and in the present embodiment, the y-direction length of the local region 115a is set to be substantially the same as the y-direction length of the corresponding pixel electrode 14 a.

Similarly, each inter-pixel electrode 15b is disposed between two pixel electrodes 14b adjacent in the x direction in a plan view, and is disposed such that a partial region (1 st region) 115b partially overlaps its own right pixel electrode 14 b. Similarly, each inter-pixel electrode 15c is disposed between two pixel electrodes 14c adjacent in the x direction in a plan view, and is disposed such that a partial region (1 st region) 115c partially overlaps its own right pixel electrode 14 c.

In the figure, the lower ends of the inter-pixel electrodes 15a, 15b, and 15c are illustrated as protruding slightly downward from the lower ends of the pixel electrodes 14a, 14b, and 14c, but the lower ends may be aligned actually. Further, the pixel electrodes may not reach the lower ends of the pixel electrodes 14a, 14b, and 14c to some extent. For example, the width (length) of each of the inter-pixel electrodes 15a, 15b, and 15c may be 80% or more of the width (length) of each of the pixel electrodes 14a, 14b, and 14 c.

Each wiring portion 16a is connected to one of the inter-pixel electrodes 15a and extends upward in the drawing. In the present embodiment, each wiring portion 16a is integrally provided with the same width as the corresponding inter-pixel electrode 15 a. Each wiring portion 16a is connected to the liquid crystal driving device 4.

Each wiring portion 16b is connected to one of the inter-pixel electrodes 15b, and extends upward in the drawing. Each wiring portion 16b is connected to the liquid crystal driving device 4. In the present embodiment, each wiring portion 16b includes: a local region (2 nd region) 116b partially overlapping the pixel electrode 14b in a plan view, the pixel electrode 14b being adjacent to the inter-pixel electrode 15b connected to the wiring portion 16b itself in the x direction; a local region (region 3) 216b disposed between the pixel electrode 14b and the pixel electrode 14a adjacent to the pixel electrode 14b in the y direction; and a local region 316b arranged to overlap with the pixel electrode 14 a. The respective partial regions 116b, 216b, 316b are integrally provided.

Similarly to the above-described local region 115b, the local regions 116b of the respective wiring portions 16b have an effect of suppressing the occurrence of dark regions in the vicinity of the upper outer edge of the pixel electrode 14b in the drawing. Therefore, the width of each local region 116b in the x direction is preferably as large as possible, and for example, the width is preferably 50% or more of the width of the corresponding pixel electrode 14a, 14 b. In the illustrated example, the width of each local region 216b is about 70% of the width of the corresponding pixel electrode 14a, 14 b.

Each local region 216b of each wiring portion 16b also functions as an inter-pixel electrode disposed between two pixel electrodes 14a and 14b adjacent to each other in the y direction. Therefore, the x-direction length of each local region 216b is preferably as long as possible, and for example, the length is preferably 50% or more of the x-direction length of the corresponding pixel electrode 14a or 14 b. In the illustrated example, the width of each local region 216b is about 70% of the length of the associated pixel electrode 14a, 14b in the x direction. By providing such a local region 216b, a region that functions substantially as a pixel region can be enlarged.

Each wiring portion 16c is connected to one of the inter-pixel electrodes 15c and extends upward in the drawing. Each wiring portion 16c is connected to the liquid crystal driving device 4. In the present embodiment, each wiring portion 16c includes: a local region (2 nd region) 116c partially overlapping the pixel electrode 14c in a plan view, the pixel electrode 14c being adjacent to the inter-pixel electrode 15c connected to the wiring portion 16c itself in the x direction; a local region (region 3) 216c disposed between the pixel electrode 14c and the pixel electrode 14b adjacent to the pixel electrode 14c in the y direction; a local region 316c arranged to overlap the pixel electrode 14b with an insulating layer 17 interposed therebetween; a local region 416c arranged to overlap the pixel electrode 14a with the insulating layer 17 interposed therebetween, the pixel electrode 14a being adjacent to the pixel electrode 14b in the y direction; and a connection region 516c disposed between the pixel electrode 14a and the pixel electrode 14b and connecting the local region 316c and the local region 416 c. The respective partial regions 116c, 216c, 316c, 416c and the connection region 516c are integrally provided.

Similarly to the above-described local region 115c, the local regions 116c of the respective wiring portions 16c have an effect of suppressing the occurrence of dark regions in the vicinity of the upper outer edge of the pixel electrode 14c in the drawing. Therefore, the length in the x direction of each local region 116c is preferably as long as possible, and for example, the length is preferably 50% or more of the length in the x direction of the corresponding pixel electrode 14b, 14 c. In the illustrated example, the length of each local region 116c is about 87% of the width of the corresponding pixel electrode 14b, 14c in the x direction.

Each local region 216c of each wiring portion 16c also functions as an inter-pixel electrode disposed between two pixel electrodes 14b and 14c adjacent to each other in the y direction. Therefore, the length in the x direction of each local region 216c is preferably as long as possible, and for example, the length is preferably 50% or more of the length in the x direction of the corresponding pixel electrode 14b, 14 c. In the illustrated example, the length of each local region 216c is about 87% of the width of the corresponding pixel electrode 14b, 14c in the x direction. By providing such a local region 216c, a region that functions substantially as a pixel region can be enlarged.

Further, the pattern of the inter-pixel electrode 15 and the wiring portion 16 may be designed as follows: the inter-pixel electrode 15 and the wiring portion 16 overlap (occupy) 80% or more of the total area defined by the gap between the pixel electrodes 14. That is, the inter-pixel electrode 15 and the wiring portion 16 may overlap with a region of 80% or more of the total region defined by the gap between the pixel electrodes 14. This can suppress the occurrence of a dark region in the vicinity of the peripheral edge of each pixel electrode 14 in the entire element (display region).

Fig. 4 is a diagram for explaining a relationship between the shape of the connection portion of each pixel electrode and the orientation processing direction. Each pixel electrode and the like are shown in a plan view, as in fig. 3. The alignment treatment refers to a treatment (uniaxial alignment treatment) for imparting an alignment regulating force (uniaxial alignment regulating force) to the alignment film in one direction, such as rubbing treatment or photo-alignment treatment. The orientation treatment direction is a direction in which the above-described orientation treatment is performed, and generally substantially coincides with a direction in which a uniaxial orientation restriction occurs. As described above, the through hole 19 provided with the connection portion 20a of each pixel electrode 14a has an outer edge of a substantially triangular shape. In the present embodiment, the direction L of the outer edge of the connection portion 20a, which is arranged so as to intersect both the left outer edge and the upper outer edge of the pixel electrode 14a in the figure, is a direction that is at an angle of approximately 45 ° with respect to both the xy directions as shown in the figure. The alignment processing direction 21 is set to a direction intersecting with (substantially perpendicular to in the present embodiment) the direction L of the outer edge and extending from the inside of the pixel electrode 14a toward the outer edge of the connection portion 20 a. The same applies to the relationship between the connection portions 20b of the pixel electrodes 14b, the connection portions 20c of the pixel electrodes 14c, and the alignment processing direction 21. The reason why the orientation processing direction 21 is preferably set as described above will be described below.

Fig. 5 is a diagram for explaining a relationship between each connection portion and the orientation processing direction. The state of the alignment film in the connection portion of each pixel electrode and the surface in the vicinity thereof is schematically shown. Fig. 5 (a) shows a state before the alignment process. As shown in the drawing, for example, the side chains 22 of the alignment film stand up from the surface at the connection portion 20a and its vicinity. Since the rising direction of the side chain 22 at this time changes according to the surface shape, the side chain 22 rises from the surface of the portion of the connection portion 20a that becomes an inclined surface along the through hole 19.

Fig. 5 (B) shows a state of the alignment film when the alignment treatment direction 21 is set and the alignment treatment (rubbing treatment) is performed in the preferred state shown in fig. 4. In this case, since the alignment treatment is performed in the direction from the right side to the left side in the figure, the side chain 22 is also slightly inclined in this direction. At this time, since the side chain 22 is inclined to the left side in the figure at any portion when viewed from the y direction in the figure, the orientation direction of the liquid crystal molecules restricted by the side chain 22 is also inclined to the left side in the figure at any portion. Therefore, the miswire can be prevented from being generated in the vicinity of the connection portion 20 a.

Fig. 5 (C) shows a comparative example, which shows the state of the alignment film when the alignment treatment (rubbing treatment) is performed with the alignment treatment direction 21 set in the opposite direction to the preferred state shown in fig. 4. In this case, since the alignment treatment is performed in the direction from the left side to the right side in the figure, the side chain 22 is also slightly inclined in this direction. At this time, when viewed from the y direction in the figure, the side chain 22 is inclined to the right in the figure at the flat portion of the pixel electrode 14a, and the side chain is inclined to the left in the figure at the inclined surface portion of the connection portion 20 a. This causes the alignment direction of the liquid crystal molecules to be opposite in the vicinity of the connection portion 20a and the periphery thereof, and an disclination line is generated at the boundary thereof. The generation of such an offset line involves a reduction in the quality of the formed light distribution pattern.

Fig. 6 is a graph showing transmittance characteristics of several samples of the liquid crystal element. Here, samples were prepared and transmittance characteristics thereof were measured, and various conditions other than cell thickness and presence/absence of addition of a chiral agent to the liquid crystal material were set in common for the samples, and the arrangement of the pair of polarizing plates was also set as described above. The homeotropic alignment film is formed by flexographic printing using a type having a rigid skeleton (liquid crystalline skeleton) in the side chain The thickness of the material is about 160 to 250 ℃ and the firing time is 1 to 1.5 hours. The pressing amount is set to 0.3 to 0.8mm for the rubbing treatment. The direction of rubbing treatment was set to be antiparallel. As the liquid crystal material, a material having a dielectric anisotropy Δ ∈ of-4.4 and a refractive index anisotropy Δ n of about 0.13 was used.

The characteristic line a shown in FIG. 6 is a sample to which the chiral agent is added at a cell thickness of 6 μm, the characteristic line b is a sample to which the chiral agent is not added at a cell thickness of 3 μm, the characteristic line c is a sample to which the chiral agent is not added at a cell thickness of 6 μm, and the characteristic line d is a sample to which the chiral agent is not added at a cell thickness of 4 μm. In the liquid crystal element of the characteristic line a and the liquid crystal element of the characteristic line b, the transmittance does not decrease and is substantially constant even when the applied voltage is increased. In contrast, in the liquid crystal element of the characteristic line c, the transmittance which temporarily increases with an increase in the applied voltage gradually decreases with a further increase in the applied voltage. In the liquid crystal element of the characteristic line d, the transmittance is saturated at a voltage of 3.8V or more, and the transmittance rapidly decreases at a voltage of 3.8V or more. Fig. 7 shows the chromaticity change of each sample of the characteristic line a and the characteristic line c. In the sample of the characteristic line a, the chromaticity hardly changes depending on the voltage change, but in the sample of the characteristic line c, the chromaticity largely changes. The sample of characteristic line b also has the same result as the sample of characteristic line a.

Here, in the liquid crystal element 5 of the present embodiment, the magnitude of the voltage effectively applied to the liquid crystal layer 18 differs between the region where the voltage is applied from each pixel electrode 14 to the liquid crystal layer 18 (hereinafter referred to as "1 st region") and the region where the voltage is applied from the inter-pixel electrode 15 to the liquid crystal layer 18 (hereinafter referred to as "2 nd region"). Depending on the difference generated by the presence or absence of the insulating layer 17. This is because, in the 2 nd region, since the insulating layer 17 exists between the inter-pixel electrode 15 and the liquid crystal layer 18, the applied voltage is divided between the insulating layer 17 and the liquid crystal layer 18. Therefore, for example, it is preferable to use a liquid crystal element having a wider range in which the transmittance is substantially constant with respect to the applied voltage, such as the samples of the characteristic lines a and b shown in fig. 8, as the liquid crystal element 5, and to apply a voltage sufficient for both the 1 st region and the 2 nd region by setting a relatively high applied voltage (for example, a voltage 1.5 times or more the threshold value). The "range in which the transmittance can be regarded as substantially constant" referred to herein means a range in which the transmittance varies by ± 3%, for example.

The difference between the actual applied voltages in the 1 st region and the 2 nd region is examined. The 2 nd region can be regarded as being formed by connecting in series a capacitance component formed in the liquid crystal layer 18 and a capacitance component generated in the insulating layer 17. I.e. can be regarded as a series connection of two capacitors.

The dielectric constant (minor axis direction) of the liquid crystal material is ∈ _LCThe area of the region is S, and the thickness of the liquid crystal layer 18 is d _LCThe capacitance component C generated in the liquid crystal layer 18 is expressed as follows _LC. Similarly, the dielectric constant of the insulating layer 17 is ∈ _topS is the area of the region, d is the thickness of the insulating layer 17 _topThe capacitance component C generated in the insulating layer 17 is represented as follows _top。

C _LC＝ε _LC×S/d _LC

C _top＝ε _top×S/d _top

Since the capacitors are connected in series and the charge amount Q is common, if the voltage applied to the liquid crystal layer 18 is set to V _LCThe voltage applied to the insulating layer 17 is set to V _topThen, it is expressed as follows.

Q＝C _LC×V _LC

Q＝C _top×V _top

For example, in a liquid crystal cell having a cell thickness of 6 μm, if d of the liquid crystal layer 18 _LC：5μm、ε _LC: 8.0, d of insulating layer 17 _top：1μm、ε _top: 3.44, the capacitance components are as follows.

C _LC＝8.0×S/5＝1.6×S

C _top＝3.44×S/1＝3.44×S

Thereby, it becomes V _LC：V _top＝1/C _LC：1/C _top＝1/1.6：1/3.44，

Becomes V _LC：V _top＝1.96：1。

From the above, in the above numerical example, the voltage division ratio of the liquid crystal layer 18 to the insulating layer 17 is 1.96: 1, referred to as substantially 2: a partial pressure ratio of 1. That is, since the insulating layer 17 is not present in the "1 st region" which is a region where a voltage is applied from each pixel electrode 14 to the liquid crystal layer 18, the voltage is basically applied directly, but in the 2 nd region which is a region where a voltage is applied from the inter-pixel electrode 15 to the liquid crystal layer 18, the applied voltage is set to be 2: 1 is applied to the liquid crystal layer 18. Therefore, in order to avoid the difference in transmittance between the 1 st region and the 2 nd region, it is preferable to use the liquid crystal element 5 which can be regarded as a condition that the transmittance is substantially constant in a wide range as described above, and to supply a relatively high applied voltage. For example, in the liquid crystal element of the characteristic line a shown in fig. 6, if the applied voltage is set to 7V, the 7V is applied to the 1 st region of the liquid crystal layer 18, and about 4.7V of the divided voltage is applied to the 2 nd region, and the same transmittance can be obtained in both regions.

In other words, the liquid crystal element 5 is preferably configured to have the following transmittance characteristics: regarding the applied voltage, the transmittance when the voltage applied to the liquid crystal layer 18 is divided by the insulating layer 17 is substantially equal to the transmittance when the voltage is directly applied to the liquid crystal layer 18 without being divided by the insulating layer 17 (for example, within an error range of ± 3%).

Fig. 8 is a plan view for explaining a modified example of the common electrode. In fig. 8, the common electrode 13a is shown overlapping with each pixel electrode 14a and the like. The illustrated common electrode 13a has openings 23 in regions corresponding to the connection regions 516c of the respective wiring portions 16 c. The shape and size of the opening 23 in plan view are preferably substantially the same as those of the connection region 516c, but the connection region 516c may be slightly larger than the connection region 516c in view of the formation accuracy, alignment accuracy, and the like in manufacturing, and the connection region 516c may be built in the opening 23 in plan view. By providing such an opening 23, unnecessary light transmission in the connection region 516c can be prevented.

Specifically, when the opening 23 is not provided, if a voltage is applied to the pixel electrode 14c and the region is set to the light-transmitting state, the same voltage is applied to the connection region 516, and therefore the connection region 516c is also set to the light-transmitting state. At this time, for example, if each region corresponding to the pixel electrode 14a or the pixel electrode 14b is in a non-transmissive state (or a low-transmissive state), it is considered that the light-transmissive state of the connection region 516c is a state that can be visually recognized as a bright point. By providing the opening 23, occurrence of such bright spots can be avoided. The connection region 516c is always in a non-transmissive state and thus can be visually recognized as a black dot, but is not easily observed by the human eye, and thus is preferable to a bright dot. In the illustrated example, the connection region 516c is used to electrically connect the local region 316c and the local region 416c, and therefore can be formed to have a relatively narrow size. Therefore, the black spot can be virtually invisible.

Fig. 9 is a plan view for explaining a modified embodiment of the pixel electrode and the inter-pixel electrode. In the illustrated example, the vertical relationship between the pixel electrode in the 3 rd column and the inter-pixel electrode is reversed, which is different from the above-described embodiment. Specifically, each pixel electrode 14c ' is provided on the lower layer side, an insulating layer 17 (see fig. 2) is provided so as to cover each pixel electrode 14c ', and each inter-pixel electrode 15c ' is provided on the insulating layer 17. The inter-pixel electrode 15c ' is provided with a connection portion 20c ', and the inter-pixel electrode 15c ' and the pixel electrode 14c ' are connected by the connection portion 20c '. Each wiring portion 16c is connected to each pixel electrode 14 c'. As in this example, the vertical relationship between the pixel electrode and the inter-pixel electrode can be switched.

Fig. 10 is a plan view for explaining a modified embodiment of the pixel electrode. In the illustrated example, the 3 rd column pixel electrode 114c is integrated and provided at a position lower than the insulating layer 17, which is different from the embodiment. As in this example, a part of the pixel electrodes may be integrated.

According to the above embodiments, the beauty of the light distribution pattern in the vehicle lamp system that controls the light distribution pattern using the liquid crystal element or the like can be improved.

In general, the common electrode 13 is sometimes referred to as a common electrode, and the pixel electrode 14 is sometimes referred to as a segment electrode. The wiring portion 16 may be referred to as a wiring electrode or a pull-around electrode, and may be regarded as a part of the inter-pixel electrode 15. Conversely, the inter-pixel electrode 15 can be regarded as a part of the wiring section 16.

Fig. 11 and 12 are overall plan views for explaining another modified embodiment of the pixel electrode (segment electrode). In addition, the segmented electrodes 14 are shown in phantom lines for convenience.

In ADB, AFS, or the like, generally, an area where light distribution control is performed more accurately (for example, the center of an illumination area) and an area where light distribution control is performed more roughly (for example, the periphery of the illumination area) are determined in advance. The size and shape of each segment electrode 14 are adjusted in accordance with the light irradiation accuracy of the illumination area.

The pixel electrodes (segment electrodes) in fig. 11 and 12 are examples of pixel electrodes arranged in a matrix. Here, the matrix state means a state in which a plurality of pixels are regularly arranged.

Fig. 11 shows an example of the arrangement in a lattice or net shape in the longitudinal and transverse directions. In the illustrated example, one electrode 14 extending in one direction (X direction) is disposed on one end side and the other end side in the Y direction, and various electrodes 14 having a relatively small size are disposed in the center. The various electrodes 14 have a tendency that the width in the Y direction gradually becomes narrower from the lower side toward the center and becomes wider again from the center toward the upper side.

Further, the electrodes 14 of the one group arranged at the center in the Y direction are arranged with relatively large-sized electrodes 14 on the left and right sides (one end side and the other end side in the X direction), and the electrodes 14 of the smaller size are arranged at the center. The one set of electrodes 14 has a tendency that the width in the left-right direction (X direction) becomes gradually narrower from the left side toward the center and becomes wider again from the center toward the right side.

Fig. 12 shows an example of the radial arrangement in the oblique direction. In the illustrated example, the electrodes 14 of the one group arranged at the center in the Y direction are arranged with relatively large-sized electrodes 14 on the left and right sides (one end side and the other end side in the X direction), and the electrodes 14 of the other group arranged at the center are arranged with relatively small-sized electrodes 14. The one set of electrodes 14 has a tendency that the width in the left-right direction (X direction) becomes gradually narrower from the left side toward the center and becomes wider again from the center toward the right side.

The electrodes 14 are arranged in a manner such that the electrodes 14 are divided by radially extending dividing lines and radially extend. Various electrodes 14 of relatively small size are arranged at the center. The various electrodes 14 have a tendency to become progressively smaller in size from the periphery toward the center and to become wider again from the center toward the periphery.

A vehicle headlamp system using a liquid crystal element 5 having a structure (multilayer electrode structure) in which segment electrodes 14 and wiring electrodes 16 (and inter-pixel electrodes 15) are laminated with an insulating layer 17 interposed therebetween, the segment electrodes 14 having a shape most suitable for ADB, AFS, or the like, and the liquid crystal element 5 has not been developed. By providing the multilayer electrode structure, even if the shape and arrangement of the segment electrodes 14 are complicated as described above, the wiring electrode 16 (the inter-electrode 15) can be easily patterned. Further, by patterning the inter-pixel electrodes 15 or the wiring electrodes 16 so as to be arranged in the gaps between the segment electrodes 14 in a plan view (see fig. 3 and the like), it is possible to suppress the occurrence of dark regions in the vicinity of the peripheral edge of each segment electrode 14.

Fig. 13 is an overall plan view for explaining another modified embodiment of the pixel electrode (segment electrode). In addition, the segmented electrodes 14 are shown in phantom lines for convenience.

In the ADB, AFS, or the like, there is a function of illuminating only a specific illumination area such as a destination guide sign or a pedestrian hanging on a road. The size and shape of each segmented electrode 14 are adjusted according to the illumination objects.

In the illustrated example, the electrodes 14 having different shapes are laid on the insulating layer 17. For example, by applying a voltage to the electrode 14 housed in the electrode region E1 surrounded by a broken line in the figure, a rectangular projection image can be output to the left side of the illumination region. By applying a voltage to the electrode 14 housed in the electrode region E2, a circular projected image can be output on the upper left side of the illumination region. Further, it is also possible to output a projected image such as desired characters ("LO", electrode region E3) or graphics (arrows or diamonds, electrode regions E4, E5) at a predetermined position in the illumination region.

By providing the multilayer electrode structure, the wiring electrode 16 (the interelectrode 15) can be easily patterned even if the shape and arrangement of the segment electrodes 14 are complicated. Further, by patterning the inter-pixel electrodes 15 or the wiring electrodes 16 so as to be arranged in the gaps between the segment electrodes 14 in a plan view (see fig. 3 and the like), it is possible to suppress the occurrence of dark regions in the vicinity of the peripheral edge of each segment electrode 14.

The present invention has been described above with reference to examples, but the present invention is not limited to these examples. For example, although the liquid crystal layer in the vertical alignment has been described as the liquid crystal layer of the liquid crystal element in the above embodiment, the structure of the liquid crystal layer is not limited thereto, and another structure (for example, TN alignment) may be adopted. Further, a viewing angle compensation sheet may be disposed between the liquid crystal element and the polarizing plate.

In the above-described embodiment, the example in which the present invention is applied to the system that selectively irradiates light in front of the vehicle has been described, but the application range of the present invention is not limited to this. For example, the present invention may be applied to a system that irradiates light diagonally forward of a vehicle according to a traveling direction of the vehicle, a system that adjusts an optical axis of a headlamp according to a front-rear direction inclination of the vehicle, a system that electronically switches high beam and low beam of the headlamp, and the like. The present invention is not limited to the vehicle application, and may be applied to a general lighting device. It should be apparent to those skilled in the art that various changes, improvements, combinations, and the like can be made.