JP7470592B2 - Liquid crystal elements, vehicle headlights - Google Patents

Description

The present invention relates to a liquid crystal element and a vehicle headlamp that uses the same.

JP 3-167039 A (Patent Document 1) describes a cornering headlamp that variably sets the headlamp's light irradiation range according to the inclination of the vehicle body in order to prevent glare on oncoming vehicles caused by changes in the headlamp's illumination range (particularly the cutoff line) due to the inclination of the motorcycle when traveling on a curved road, etc.

The headlights described above have room for improvement in that relatively large dark spots (black spots) appear in the light emitted, which can impair the appearance of the light emitted.

Japanese Patent Application Laid-Open No. 3-167039

One of the objectives of a specific embodiment of the present invention is to improve the appearance of the illuminated light, which is variable according to the inclination of the vehicle body.

[1] A liquid crystal element according to one aspect of the present invention is a liquid crystal element including: (a) a first substrate and a second substrate disposed opposite each other; (c) a liquid crystal layer disposed between the first substrate and the second substrate; (d) a common electrode provided on one surface side of the first substrate; and (e) a plurality of pixel electrodes provided on one surface side of the second substrate, (f) a pixel portion is formed in each region where each of the plurality of pixel electrodes and the common electrode overlap in a planar view; (g) each of the plurality of pixel electrodes is disposed separately from each other by gaps corresponding to a plurality of virtual dividing lines; (h) the plurality of virtual dividing lines are set such that the larger the angle they form with a first direction, the farther the intersection point with a virtual center line along a second direction substantially perpendicular to the first direction is from the virtual center point on the virtual center line; and (i) the plurality of pixel electrodes have planar shapes that are linearly symmetrical with respect to the virtual center line .
[2] One aspect of the present invention provides a vehicle headlamp including: (a) the liquid crystal element according to [1]; (b) a light source that introduces light into the liquid crystal element; (c) a pair of polarizing plates that are disposed opposite each other and sandwich the liquid crystal element; and (d) a projection lens that projects an image generated by the liquid crystal element and the pair of polarizing plates.

The above configuration improves the appearance of the illuminated light, which varies depending on the inclination of the vehicle body.

FIG. 1 is a diagram showing a schematic configuration of a two-wheeled vehicle equipped with a vehicle headlamp according to an embodiment. FIG. 2 is a diagram showing a configuration of a vehicle headlamp according to an embodiment. 3A and 3B are diagrams for explaining the outline of the state of light irradiation by a vehicle headlamp. Fig. 4 is an enlarged view of a portion a shown in Fig. 3(A) Fig. 4(B) is a diagram for explaining how to determine the shape and arrangement of each individual region. FIG. 5 is a plan view showing an example of pixel electrodes provided corresponding to each pixel portion in the portion a shown in FIG. Fig. 6A is a schematic cross-sectional view showing a configuration of a liquid crystal element, and Fig. 6B is a schematic cross-sectional view showing another configuration example of the liquid crystal element. FIG. 7 is a diagram showing individual regions in a vehicle headlamp according to another embodiment. FIG. 8 shows an example of the configuration of a liquid crystal element for providing each individual region in another embodiment. FIG. 9 illustrates an example of a method for determining the position of each division line. FIG. 10 is a partially enlarged view of a plurality of pixel portions in a liquid crystal element of a reference example.

First, the reason why a relatively large dark spot may occur in the light emitted by a vehicle headlamp (vehicle lamp) when the liquid crystal element of the reference example is used will be described in detail. FIG. 10 is a partially enlarged view of a plurality of pixel units in the liquid crystal element of the reference example. The liquid crystal element of the reference example includes a plurality of pixel units 210, 211, 212, and 213. In detail, the pixel unit 210 is an inverted triangular pixel unit in the upper center, the pixel unit 211 is a triangular pixel unit in the lower center, each pixel unit 212 is a pixel unit arranged radially on the right side, and each pixel unit 213 is a pixel unit arranged radially on the left side. Each pixel unit 210, 211, 212, and 213 is arranged radially so that one end of each of them converges toward the center. By individually controlling the transmittance of these pixel units 210, etc., and projecting the transmitted light by making light incident on each pixel unit 210, etc., the light irradiation range of the headlamp can be variably set according to the inclination of the vehicle body.

Here, each pixel section 210, 211, 212, 213 has a certain amount of gap between adjacent ones (not shown). These gaps are for preventing short-circuiting between electrodes corresponding to adjacent pixel sections 210, etc., and require a width of, for example, about 10 μm, depending on the etching accuracy during manufacturing. For this reason, a relatively large blank area 220 is generated between one end of each pixel section 210, etc. The blank area 220 can have a width (diameter) of, for example, about 300 μm. Since the blank area 220 is an area where no pixel section is arranged, for example, if the liquid crystal element is a normally black type, the blank area 220 is always in a light-shielding state. The size of the dark spot generated in the irradiated light by this blank area 220 can be very noticeable when projected forward of a motorcycle or the like. In contrast, in the vehicle headlamp of the embodiment disclosed below, the shape of each pixel section of the liquid crystal element is devised to prevent large dark spots from occurring.

Figure 1 is a diagram showing the schematic configuration of a motorcycle equipped with a vehicle headlamp of one embodiment. As shown in Figure 1, the vehicle headlamp 100 of this embodiment is installed at a predetermined position on the front of the motorcycle 101 and is intended to illuminate the area ahead of the motorcycle 101. As shown in Figure 1, when the motorcycle 101 is traveling on a curved road, the rider tilts the motorcycle 101 to the left or right depending on the direction of travel. At this time, as the motorcycle 101 leans, the vehicle headlamp 100 also leans to the left or right as shown in the figure.

Figure 2 is a diagram showing the configuration of a vehicle headlamp according to one embodiment. The vehicle headlamp 100 shown in Figure 2 is for irradiating light ahead of the vehicle by variably setting the light irradiation range and dimming range (or non-irradiation range) according to the left-right tilt angle of the two-wheeled vehicle 101 detected by the tilt sensor 2. This vehicle headlamp 100 includes a light source 1, a tilt sensor 2, a controller 3, a driver 4, a liquid crystal element 5, a pair of polarizing plates 6a, 6b, and a projection lens 7. The controller 3 is connected to the light source 1, the tilt sensor 2, and the driver 4. The driver 4 is connected to the liquid crystal element 5.

The light source 1 is configured to include a white light LED that is configured by combining a light emitting element (LED) that emits blue light with a yellow phosphor. The light source 1 includes, for example, a plurality of white light LEDs arranged in a matrix or line. In addition to LEDs, the light source 1 can be a laser or a light source commonly used in vehicle lamp units such as a light bulb or a discharge lamp. The on/off state of the light source 1 is controlled by the controller 3. The light emitted from the light source 1 is incident on the liquid crystal element (liquid crystal panel) 5 via a polarizing plate 6a. In addition, other optical systems (for example, a lens, a reflector, or a combination thereof) may be present on the path from the light source 1 to the liquid crystal element 5.

The tilt sensor (inclination sensor) 2 is installed on the two-wheeled vehicle 101 to detect the tilt angle of the two-wheeled vehicle 101. The tilt angle here is the angle of tilt when the two-wheeled vehicle 101 tilts to the left or right as shown in FIG. 1 above, and is shown as an angle based on the vertical direction, for example. In this case, when there is no tilt, the tilt angle θ = 0°.

The controller 3 sets the dimming range and the light irradiation range according to the tilt angle detected by the tilt sensor 2, generates a control signal for forming an image corresponding to a light distribution pattern including the dimming range and the light irradiation range, and supplies the control signal to the driver 4. This controller 3 is realized by executing a predetermined operating program in a computer system having, for example, a CPU, ROM, RAM, etc.

The driver 4 individually controls the alignment state of the liquid crystal layer in each pixel of the liquid crystal element 5 by supplying a drive voltage to the liquid crystal element 5 based on a control signal supplied from the controller 3. The driver 4 may be mounted on the substrate of the liquid crystal element 5 using, for example, COG (Chip On Glass) technology.

The liquid crystal element 5 has a plurality of pixel sections (light modulation regions) that can be controlled individually, and the light modulation state (liquid crystal layer alignment state) of each pixel section is variably set according to the magnitude of the voltage applied to the liquid crystal layer given by the driver 4. The liquid crystal element 5 is irradiated with light from the light source 1 through the polarizing plate 6a, and the transmitted light passes through the polarizing plate 6b, forming an image having brightness (or color tone in addition to this) corresponding to the above-mentioned light irradiation range and dimming range. For example, the liquid crystal element 5 has a vertically oriented liquid crystal layer and is arranged between a pair of polarizing plates 6a and 6b arranged in crossed Nicols. When no voltage is applied to the liquid crystal layer (or a voltage below a threshold value) in each pixel section, the light transmittance is extremely low (light blocking state), and when a voltage is applied to the liquid crystal layer, the light transmittance is relatively high (transmitting state).

The pair of polarizing plates 6a, 6b are arranged facing each other with the liquid crystal element 5 sandwiched between them, with their polarization axes approximately perpendicular to each other. In this embodiment, a normally black type is assumed, which is an operating mode in which light is blocked (transmittance is extremely low) when no voltage is applied to the liquid crystal layer. For each of the polarizing plates 6a, 6b, for example, an absorption type polarizing plate made of a general organic material (iodine-based, dye-based) can be used. In addition, if heat resistance is important, it is also preferable to use a wire grid type polarizing plate. A wire grid type polarizing plate is a polarizing plate made of an arrangement of extremely fine lines made of metal such as aluminum. In addition, an absorption type polarizing plate and a wire grid type polarizing plate may be used in a stacked manner.

The projection lens 7 expands the image formed by the light passing through the liquid crystal element 5 (an image having brightness corresponding to the light irradiation range and the dimming range) and projects it forward of the motorcycle 101, and an appropriately designed lens is used. In this embodiment, an inverted projection type projector lens is used.

3(A) and 3(B) are diagrams for explaining the outline of the light irradiation by the vehicle headlamp. FIG. 4 is an enlarged view of part a shown in FIG. 3(A). The light irradiated by the vehicle headlamp can be switched on and off individually for each of the individual regions 20-33 and 40-53. "On" here means that the light is irradiated and the state is relatively bright, and "off" means that no light is irradiated or only very weak light is irradiated and the state is relatively dark. The individual regions with patterns in the figure are lit. The V line is parallel to the vertical direction, and the H line is parallel to the horizontal direction. In reality, the light distribution can be controlled finely according to the inclination angle of the motorcycle 101 by dividing each individual region into smaller parts. However, for the sake of convenience, an embodiment with a reduced number of individual regions is illustrated here.

When traveling straight and the road surface is not inclined, and the motorcycle 101 is not inclined, the vehicle headlamp 100 is not inclined either, so the individual areas 20, 22, 23, 24, 28, 29, 30 (see FIG. 3A) and the individual areas 40, 41, 42, 43, 47, 48, 52, 53, 54 (see FIG. 4A) that correspond above the H line are turned off, and the individual areas below the H line are turned on. This makes it possible to prevent glare to the oncoming vehicle 102.

On the other hand, when the motorcycle 101 tilts when traveling on a curved road and/or when the road surface is inclined, the vehicle headlamp 100 also tilts, so for example, the individual areas 20, 22, 23, 28, 29, 30, 31 (see FIG. 3B) and the individual areas 40, 41, 42, 43, 50, 51, 52, 53 (see FIG. 4A) above the H line are turned off, and the individual areas below the H line are turned on. This makes it possible to prevent glare to the oncoming vehicle 102. This makes it possible to prevent glare to the oncoming vehicle 102 even when the motorcycle 101 tilts. Note that the control mode in FIG. 3B is an example, and the turning on and off of each individual area is appropriately selected depending on the tilt direction and tilt angle of the motorcycle 101.

Figure 4 (B) is a diagram for explaining how to determine the shape and arrangement of each individual region. As shown in the figure, dividing lines 60, 61, 62, 63, 64, 65, and 66 are set to divide the individual regions. These dividing lines 60 to 66 correspond to the positions where the cutoff line (the boundary between the light region and the dark region) is provided in the irradiated light according to the tilt direction and tilt angle of the motorcycle 101. In detail, the dividing lines 60 to 62 are each straight lines extending from the upper right side to the lower left side in the figure, and each obliquely intersects with the H line. The angle between each line and the H line is the largest with the dividing line 60, the next largest with the dividing line 61, and the smallest with the dividing line 62. Similarly, the dividing lines 64 to 66 are each straight lines extending from the upper left side to the lower right side in the figure, and each obliquely intersects with the H line. The angle between each of the lines and the H line is the largest with the dividing line 64, the next largest with the dividing line 65, and the smallest with the dividing line 66. The dividing lines 60 and 64, the dividing lines 61 and 65, and the dividing lines 62 and 66 are symmetrically arranged in the left-right direction. Therefore, the intersections of the dividing lines 60 and 64 with the V line are at the same position, which is designated as X1. Similarly, the intersections of the dividing lines 61 and 65 with the V line are at the same position, which is designated as X2. Similarly, the intersections of the dividing lines 62 and 66 with the V line are at the same position, which is designated as X3. The dividing line 63 is a straight line that is disposed below the V line and extends parallel to the V line, and intersects the H line at a substantially right angle. The intersection of the dividing line 66 with the V line is designated as X4.

In this embodiment, the arrangement of the dividing lines 60 to 66 is set so that the intersections X1 to X4 of each dividing line for setting each individual region are not gathered at the same position on the V line (on a virtual reference line along the vertical direction) but are distributed in the vertical direction. More specifically, the arrangement of each dividing line is determined so that the intersections of the dividing line and the V line that form a larger angle with the H line, i.e., the horizontal direction, are relatively higher on the V line. In the illustrated example, the arrangement of the dividing lines 60 to 66 is determined so that the intersection X1 of the dividing lines 60, 64 and the V line is the uppermost, the intersection X2 of the dividing lines 61, 65 and the V line is the next highest, the intersection X3 of the dividing lines 62, 66 and the V line is the next highest, and the intersection X4 of the dividing line 63 and the V line is the lowest. The dividing line 66 is substantially parallel to the horizontal direction, and the intersection X4 between the dividing line 66 and the V line is the virtual reference point located at the lowest position among the multiple intersections. The other intersections X1, X2, and X3 are arranged in this order at positions far from the intersection X4, which is the virtual reference point. Then, individual areas are provided corresponding to the areas divided by the dividing lines 60 to 66 arranged in this manner (see FIG. 4A). In this way, it is possible to prevent the ends of each individual area from concentrating in one place, and therefore it is possible to prevent the occurrence of large dark spots. Also, as shown in each figure, each individual area has a shape that is line-symmetrical with respect to the V line. Furthermore, in this embodiment, there are diamond-shaped individual areas 40 and 41 that are arranged at a position that overlaps with the V line in a plan view. These diamond-shaped individual areas 40 and 41 are the individual areas that overlap with the V line among the individual areas defined by the intersection of the dividing lines 60 to 62 and 64 to 66 that are arranged symmetrically with respect to the H line.

To achieve the above-described lighting/extinguishing in each individual region, for example, a liquid crystal element having multiple pixel electrodes of a planar shape corresponding to each individual region and a common electrode arranged opposite these pixel electrodes is used, and light from a light source is made to enter this liquid crystal element, and the voltage applied between each pixel electrode and the common electrode is individually controlled.

Figure 5 is a plan view showing an example of pixel electrodes provided corresponding to each pixel portion in part a shown in Figure 3 (A). Figure 5 also shows the state of wiring for each pixel electrode. As shown in the figure, each pixel electrode has a planar shape corresponding to each of the individual regions 20 to 33 and 40 to 53 shown in Figure 4 (A) described above, and is provided in a shape that is line-symmetrical with respect to the imaginary center line o. In addition, each pixel electrode is physically and electrically separated from each other by a gap in plan view where no conductor such as a conductive film is present. In addition, the two pixel electrodes corresponding to the diamond-shaped individual regions 40 and 41 described above are arranged at a position that overlaps with the imaginary center line o.

In detail, the gap 70 is provided based on a virtual dividing line corresponding to the above-mentioned dividing line 60, and extends from the upper right side to the lower left side in the figure. Similarly, the gap 71 is provided based on a virtual dividing line corresponding to the above-mentioned dividing line 61, the gap 72 is provided based on a virtual dividing line corresponding to the above-mentioned dividing line 62, the gap 73 is provided based on a virtual dividing line corresponding to the above-mentioned dividing line 63, the gap 74 is provided based on a virtual dividing line corresponding to the above-mentioned dividing line 64, the gap 75 is provided based on a virtual dividing line corresponding to the above-mentioned dividing line 65, and the gap 76 is provided based on a virtual dividing line corresponding to the above-mentioned dividing line 66. Note that the virtual dividing line refers to a virtual dividing line that is similar to each dividing line that divides the above-mentioned individual regions and has an appropriate scale adjusted to fit the size of the pixel electrode, and is illustrated as in FIG. 4(B). The gaps 70 to 76 are each provided in a straight line, and the intersections with a predetermined virtual center line o are distributed and arranged in the same manner as the intersections X1 to X4 of the above-mentioned dividing lines. In detail, the intersections are arranged so that the virtual center point corresponding to intersection X4 is at the bottom, and the other intersections corresponding to intersections X1 to X3 are located in that order farthest from the virtual center point. The pixel electrodes are separated from each other by gaps 70 to 76.

The wiring used to apply voltage to each pixel electrode may be provided, for example, below the layer on which each pixel electrode is provided, isolated via an insulating layer. This allows each wiring 78 to be placed below the pixel electrode, even if the number of pixel electrodes is large and the shape is complex, as shown in Figure 5 by the dotted lines and black circles indicating the wiring connection state to each pixel electrode.

Figure 6 (A) is a schematic cross-sectional view showing the configuration of a liquid crystal element. The liquid crystal element 5 includes an upper substrate (first substrate) 11 and a lower substrate (second substrate) 12 arranged opposite each other, a common electrode (opposite electrode) 13, a plurality of pixel electrodes 14, a plurality of wirings (wiring electrodes) 16, an insulating layer (insulating film) 17, and a liquid crystal layer 18.

The upper substrate 11 and the lower substrate 12 are each, for example, rectangular substrates in a plan view, and are arranged opposite each other. Each substrate may be, for example, a transparent substrate such as a glass substrate or a plastic substrate. Between the upper substrate 11 and the lower substrate 12, spherical spacers (not shown) made of, for example, a resin film are dispersed and arranged, and the substrate gap is maintained at a desired size (for example, about several μm) by these spherical spacers. Note that instead of the spherical spacers, columnar bodies made of, for example, a resin may be provided on the upper substrate 11 side or the lower substrate 12 side, and these may be used as spacers.

The common electrode 13 is provided on one side of the upper substrate 11. This common electrode 13 is provided integrally with each pixel electrode 14 of the lower substrate 12 so as to face each other. The common electrode 13 is formed by appropriately patterning a transparent conductive film such as indium tin oxide (ITO).

The pixel electrodes 14 are provided on one side of the lower substrate 12, above the insulating layer 17. These pixel electrodes 14 are formed by appropriately patterning a transparent conductive film such as indium tin oxide (ITO). Each of the overlapping areas of the common electrode 13 and each pixel electrode 14 constitutes the pixel section (light modulation area). Each pixel electrode 14 is provided in the shape shown in FIG. 5.

The wiring 16 is provided on one side of the lower substrate 12 below the insulating layer 17. These wiring 16 are formed by appropriately patterning a transparent conductive film such as indium tin oxide (ITO). Each wiring 16 is for applying a voltage from the driver 4 to each pixel electrode 14, and is connected to one of the pixel electrodes 14 via a through hole provided in the insulating layer 17. These wiring 16 correspond to the wiring 78 shown by the dotted line in FIG. 5 above. Each wiring 16 is provided below each pixel electrode 14 via the insulating layer 17, which increases the degree of freedom in the layout design of the wiring and pixel electrodes.

The insulating layer 17 is provided on one surface of the lower substrate 12, above the wirings 16, so as to cover them. That is, the insulating layer 17 is provided so as to cover almost the entire surface of one surface of the lower substrate 12. This insulating layer 17 is, for example, a _SiO2 film or a SiON film, and can be formed by a gas phase process such as a sputtering method or a solution process. Note that an organic insulating film may be used as this insulating layer 17. The thickness of the insulating layer 17 is, for example, about 1 μm.

The liquid crystal layer 18 is provided between the upper substrate 11 and the lower substrate 12. In this embodiment, the liquid crystal layer 21 is formed using a nematic liquid crystal material that has a negative dielectric anisotropy Δε, contains a chiral material, and has fluidity. In this embodiment, the liquid crystal layer 18 is set so that the alignment direction of the liquid crystal molecules is tilted in one direction when no voltage is applied, and is aligned approximately perpendicular to the surfaces of the substrates with a pretilt angle, for example, in the range of 85° to 90°.

Although not shown, an alignment film for regulating the alignment state of the liquid crystal layer 18 is provided on one side of each of the upper substrate 11 and the lower substrate 12 as appropriate. For example, in this embodiment, a vertical alignment film that regulates the alignment state of the liquid crystal layer 18 to vertical alignment is used. Also, it is connected to the driver 4 via the common electrode 13, each pixel electrode 14, each wiring 16, etc., and is driven statically, for example. The common electrode 13 may be divided into multiple parts to perform duty driving (multiplex driving).

Figure 6 (B) is a schematic cross-sectional view showing another example of the configuration of a liquid crystal element. The difference from the liquid crystal element shown in Figure 6 (A) above is that multiple inter-pixel electrodes 15 are provided, so only the difference will be described in detail. The multiple inter-pixel electrodes 15 are provided on one side of the lower substrate 12, below the insulating layer 17. Each inter-pixel electrode 15 is arranged at a position overlapping the gap between adjacent pixel electrodes 14 in a plan view. Each pixel electrode 15 is connected to one wiring 16 on the back or front side of the paper (not shown). These inter-pixel electrodes 15 are formed by appropriately patterning a transparent conductive film such as indium tin oxide (ITO).

Each inter-pixel electrode 15 is connected to one adjacent pixel electrode 14 via a through hole. When a voltage is applied to a pixel electrode 14, the inter-pixel electrodes 15 and pixel electrodes 14 are at the same potential by applying a voltage from the wiring section 16 via the inter-pixel electrodes 15 connected to that pixel electrode 14, so that a voltage can be applied to the liquid crystal layer 18 even between the pixel electrodes 14. This makes it possible to control the transmission state or light-shielding state even between pixel sections, thereby suppressing or reducing the occurrence of dark lines between pixel sections.

7 is a diagram showing each individual area of a vehicle headlamp of another embodiment. The number of individual areas is increased compared to the above embodiment, making the light distribution pattern more precise. The shape and position of each individual area in the embodiment shown in FIG. 7 are set in the same manner as in the above embodiment (see FIG. 4(B)), and the ends of each individual area are not concentrated in one place but are distributed. FIG. 8 shows an example of the configuration of a liquid crystal element for providing each individual area. The liquid crystal element 5b shown in FIG. 8 has a pixel area 80 having a plurality of pixel parts having a planar shape corresponding to each individual area shown in FIG. 7. In addition, in the liquid crystal element 5b shown in FIG. 8, the lower substrate 12 is larger than the upper substrate 11, and the driver 4 is provided in the marginal part by COG technology. The control signal and power are supplied to the driver 4 via a flexible wiring board 81 connected to the driver 4. The overall configuration of the vehicle headlamp is the same as the above embodiment (see FIG. 2). In addition, since the image is inverted and projected by the projection lens 7, the actual arrangement of the liquid crystal element 5b is made upside down and left and right to that shown in the figure.

Referring again to FIG. 7, the configuration of each individual area will be described in detail. The dividing line 90a is arranged at an angle of 38.2° (deg) in an upward-right direction with respect to the H line. For example, if the inclination angle of the motorcycle 101 is 38.2°, the dividing line 90a is used as a boundary to follow the inclination of the motorcycle 101, and the individual areas below the dividing line 90a are turned on and the individual areas above the dividing line are turned off. This forms a horizontal cutoff line to prevent glare on the motorcycle 101. Similarly, the dividing line 91a has an angle of 27.7° with respect to the H line, the dividing line 92a has an angle of 21.5° with respect to the H line, the dividing line 93a has an angle of 17.5° with respect to the H line, the dividing line 94a has an angle of 14.7° with respect to the H line, the dividing line 95a has an angle of 8.9° with respect to the H line, and the dividing line 96a has an angle of 4.5° with respect to the H line. Also, the intersections of the dividing lines 90a to 96a with the V line are arranged so that the intersections with the dividing lines that form larger angles with the H line are located relatively farther away from the virtual reference point P along the V line and further upward. Also, the dividing lines 90b to 96b are set symmetrically with the dividing lines 90a to 96a, and the intersections of the corresponding dividing lines (for example, the dividing lines 90a and 90b) are located at the same positions. In addition, the division line 97 is parallel to the line H and is disposed below the line H. The intersection of the division line 97 and the line V is the virtual reference point P described above.

Now, with reference to Figures 7 and 9, an example of a method for determining the positions of the intersections of each of the dividing lines 90a-96a, 90b-96b and the V line will be described. The intersections of each of the dividing lines and the V line are dispersed and located above the virtual reference point P, which is the intersection of the dividing line 97 and the V line, in the figure. The height (lamp height) of the installation position of the vehicle headlamp 100 on the motorcycle 101 is assumed to be h [unit: m] (see Figure 2). For example, if the lamp height h is 0.85 m when the inclination angle θ is 0°, the irradiation distance (reaching distance) of the irradiation light at an angle downward by 0.57° (deg) from the cutoff line (corresponding to the H line) defined by current regulations in Japan is approximately 85 m.

Here, when the inclination angle θ is changed, if the irradiated light is directed downward by 0.57° as described above, the greater the inclination angle θ, the smaller the lamp height h of the vehicle headlamp 100 (i.e., the lower the position), and the shorter the irradiation distance. For example, when the inclination angle θ is 38.2°, the irradiation distance is 67.1 m. Therefore, in order to make the irradiation distance about 85 m at any inclination angle θ, it is necessary to change the cutoff angle φ, which is an angle defined downward from the horizontal direction of the irradiated light. For example, when the inclination angle θ is 38.2°, in order to make the irradiation distance about 85 m, it is necessary to set the cutoff angle φ to 0.45°. The same applies to other inclination angles θ. These relationships are shown in a table in FIG. 9. The cutoff angle φ is obtained by calculating tan ⁻¹ (h/85). As shown in the figure, there is a correlation in which the cutoff angle φ becomes smaller as the inclination angle θ increases. Therefore, using the cutoff angle φ of 0.57° when the inclination angle θ is 0° as a reference, the cutoff angle φ for each inclination angle θ is calculated, and the intersection of each dividing line 90a etc. with the V line is determined corresponding to the difference between the cutoff angle φ and the reference value of 0.57° (for example, 0.12° when the inclination angle θ is 38.2°).

According to the above embodiment, it is possible to improve the appearance of the illuminated light, which is variable according to the inclination of the vehicle body.

The present invention is not limited to the contents of the above-described embodiments, and can be implemented in various modified forms within the scope of the gist of the present invention. For example, the configurations of the individual regions and the corresponding pixel sections in the above-described embodiments are merely examples, and the present invention is not limited to these.

In addition, in the above embodiment, the liquid crystal layer of the liquid crystal element is described as being vertically aligned, but the configuration of the liquid crystal layer is not limited to this, and other configurations (e.g., TN orientation) may also be used. Also, a viewing angle compensation plate may be disposed between the liquid crystal element and the polarizing plate. Also, the inter-pixel electrodes may be omitted.

In addition, in the above embodiment, a vehicle headlamp that selectively irradiates light to the front of a motorcycle is illustrated, but the scope of application of this disclosure is not limited to this. Furthermore, this disclosure may be applied to lighting devices in general, not limited to vehicle applications.

1: Light source, 2: Tilt sensor, 3: Controller, 4: Driver, 5, 5a: Liquid crystal element, 6a, 6b: Polarizer, 7: Projection lens, 11: Upper substrate, 12: Lower substrate, 13: Common electrode, 14: Pixel electrode, 15: Inter-pixel electrode, 16: Wiring section, 17: Insulation layer, 18: Liquid crystal layer

Claims (10)

A liquid crystal element for generating an image corresponding to a light distribution pattern of a vehicle headlamp,
A first substrate and a second substrate disposed opposite each other;
a liquid crystal layer disposed between the first substrate and the second substrate;
A common electrode provided on one surface side of the first substrate;
A plurality of pixel electrodes provided on one surface side of the second substrate;
Including,
a pixel portion is formed in each region where each of the plurality of pixel electrodes and the common electrode overlap in a plan view,
The pixel electrodes are arranged separately from one another by gaps corresponding to a plurality of virtual division lines,
the plurality of virtual dividing lines are set such that the larger the angle the virtual dividing lines form with a first direction, the more distant the intersection point with a virtual center line along a second direction perpendicular to the first direction is from the virtual center point on the virtual center line,
the plurality of pixel electrodes have planar shapes that are line-symmetric with respect to the virtual center line;
Liquid crystal element. the virtual center point is an intersection point between the virtual center line and one of the plurality of virtual dividing lines that is substantially parallel to the first direction,
The liquid crystal device according to claim 1 . the plurality of pixel electrodes include at least one pixel electrode having a rhombic shape in a plan view,
The diamond-shaped pixel electrode is disposed at a position overlapping the virtual center line.
3. A liquid crystal device according to claim 1 or 2. A plurality of wirings arranged on one surface side of the second substrate;
an insulating layer disposed on one surface side of the second substrate so as to cover the plurality of wirings;
Further comprising:
the plurality of pixel electrodes are disposed on a surface of the insulating layer that does not contact the second substrate, and each of the pixel electrodes is connected to one of the plurality of wirings through a through hole in the insulating layer;
4. A liquid crystal device according to claim 1. A liquid crystal element according to any one of claims 1 to 4,
A light source that causes light to be incident on the liquid crystal element;
a pair of polarizing plates disposed opposite to each other with the liquid crystal element interposed therebetween;
a projection lens that projects an image generated by the liquid crystal element and the pair of polarizing plates;
2. A vehicle headlamp comprising: the projection lens projects the image into a plurality of individual regions, each of which can be independently switched on or off;
The individual regions are associated with the pixel electrodes of the liquid crystal element.
6. A vehicle headlamp according to claim 5. Each of the plurality of individual regions is divided by a plurality of division lines,
The plurality of dividing lines are set such that, when a vehicle on which the vehicle headlamp is mounted is not tilted, the larger the angle the dividing lines form with the horizontal direction, the more distant the intersection point with a virtual reference line along a vertical direction is from a virtual reference point on the virtual reference line.
7. A vehicle headlamp according to claim 6. The individual regions have planar shapes that are line-symmetric with respect to the virtual reference line.
8. A vehicle headlamp according to claim 7. the virtual reference point is an intersection point between one of the plurality of dividing lines, which is substantially parallel to a horizontal direction, and the virtual reference line when the vehicle is not tilted;
8. A vehicle headlamp according to claim 7. The plurality of individual regions include at least one individual region that is rhombic in plan view,
The individual diamond-shaped regions are arranged at positions overlapping the virtual reference line.
The vehicle headlamp according to any one of claims 7 to 9.

Images