JP6422361B2 - Vehicle headlamp unit, vehicle headlamp system - Google Patents

Description

  The present invention relates to a vehicle headlamp unit for performing selective light irradiation corresponding to a position of a vehicle ahead and the like, and a vehicle headlamp system including the vehicle headlamp unit.

  Conventionally, the irradiation range and non-irradiation range of light from the headlamp unit of the own vehicle are determined according to the position of an oncoming vehicle or a preceding vehicle (hereinafter referred to as a “front vehicle”) in front of the own vehicle. There are known vehicle headlamp systems to set. A prior example regarding such a vehicle headlamp system is disclosed in, for example, Japanese Patent Laid-Open No. 7-108873 (Patent Document 1). In this type of vehicle headlamp system, a camera is installed at a predetermined position in front of the host vehicle (for example, at the upper center of the front window), and the position of the vehicle body of the front vehicle, the taillight, or the headlight captured by the camera. Are detected by image processing. Then, light distribution control is performed so that the detected head vehicle portion is not irradiated with light from the headlamp unit of the host vehicle.

  Moreover, as a preceding example of a vehicle headlamp that can be applied to the above light distribution control, for example, Japanese Translation of PCT International Application No. 2009-534790 (Patent Document 2) discloses a liquid crystal element. . A lamp unit for a vehicle adaptive front lighting system disclosed in this document includes a liquid crystal element configured to receive light emitted by a light source, and the liquid crystal element is used when light passes through the liquid crystal element. And a first state configured to transmit incident light without substantially refracting incident light, and a second state configured to refract incident light, and the liquid crystal element Is a lamp unit that is controlled based on signals received from the adaptive front lighting system.

  By the way, in the prior example which concerns on patent document 2, although the thing using refraction and scattering is used as a liquid crystal element, these liquid crystal elements are liquid crystal elements for display (liquid crystal display elements) used for a liquid crystal television etc. In contrast, the light / dark ratio (contrast ratio) is low, and there is room for improvement in that the necessary illumination cannot always be sufficiently cut when used for light distribution control of a vehicle headlamp.

JP-A-7-108873 Special table 2009-534790 gazette

  A specific aspect of the present invention is to provide a vehicle headlamp unit or the like that has a high contrast ratio of bright and dark light and that can sufficiently cut off illumination.

  A vehicle headlamp unit according to an aspect of the present invention is a vehicle headlamp unit for selectively irradiating light ahead of the host vehicle, and includes (a) a light source and (b). A parallel optical system that converts the light from the light source into parallel light; and (c) two first surfaces and a second surface, and the polarization directions of the light emitted from the parallel optical system are orthogonal to each other. A polarizing beam splitter that separates the light and emits the light from each of the first surface and the second surface; (d) a reflecting mirror disposed opposite to the second surface of the polarizing beam splitter; and (e) the polarized light. In each of a first region where light emitted from the first surface of the beam splitter is incident and a second region where light emitted from the second surface of the polarizing beam splitter and reflected by the reflecting mirror is incident Without rotating the polarization direction of the light A reflective liquid crystal element capable of switching the first state to be rotated and the second state to be reflected by rotating the polarization direction for each predetermined section; and (f) reflected again by the first region of the reflective liquid crystal element. Projection that projects light that has passed through the polarizing beam splitter and light that has been reflected by the second region of the reflective liquid crystal element, reflected by the reflecting mirror, and again passed through the polarizing beam splitter, to the front of the host vehicle A vehicle headlamp unit including an optical system.

  A vehicle headlamp unit according to another aspect of the present invention is a vehicle headlamp unit for selectively irradiating light in front of the host vehicle. A light source that emits light of one wavelength, (b) a parallel optical system that converts light from the light source into parallel light, and (c) a first surface and a second surface, A polarizing beam splitter that splits outgoing light into two light beams whose polarization directions are orthogonal to each other and emits the light from each of the first surface and the second surface; and (d) the second surface of the polarizing beam splitter; Reflecting mirrors disposed opposite to each other, (e) a first region where light emitted from the first surface of the polarizing beam splitter is incident, and a second region of the polarizing beam splitter that is emitted from the second surface and reflected by the reflecting mirror. In each of the second regions where the incident light is incident, A reflective liquid crystal element capable of switching, for each predetermined section, a first state in which the polarization direction of the incident light is reflected without rotating and a second state in which the polarization direction is rotated and reflected; and (f) the reflective liquid crystal. The light reflected by the first region of the element and again passed through the polarizing beam splitter, and reflected by the second region of the reflective liquid crystal device and reflected by the reflecting mirror and again through the polarizing beam splitter. A phosphor that emits fluorescence having a second wavelength different from the first wavelength by being excited by each of the light that has passed; and (g) a mixed color light of the fluorescence from the phosphor and the light that has passed through the phosphor. It is a vehicle headlamp unit including a projection optical system that projects forward of the host vehicle.

  According to the configuration of any one of the above aspects, a vehicle headlamp unit having a high contrast ratio of bright and dark light and capable of sufficiently cutting illumination can be obtained.

  In the vehicle headlamp unit of each aspect described above, the light distribution pattern in each of the first region and the second region of the reflective liquid crystal element is the same, and the same light distribution pattern overlaps each other. It is also preferable that they are synthesized by the polarization beam splitter.

  In the vehicle headlamp unit of each aspect described above, the light distribution pattern in each of the first region and the second region of the reflective liquid crystal element is different, and the different light distribution patterns overlap each other. It is also preferable to combine with a polarization beam splitter.

  A vehicle headlamp system according to an aspect of the present invention is a vehicle headlamp system including the vehicle headlamp unit described above and a lighting control device that controls the operation of the vehicle headlamp unit. is there.

  According to the above configuration, a vehicular headlamp system can be obtained that has a high contrast ratio of bright and dark light and can sufficiently cut off illumination. In addition, since any two light beams having different polarization directions emitted from the polarization beam splitter can be used for illumination, the light use efficiency can be further increased.

It is a schematic diagram for demonstrating the vehicle lamp unit of 1st embodiment. It is a figure for demonstrating the principle in which the brightness of the irradiation light of the vehicle lamp unit of 1st embodiment is switched. It is a figure for demonstrating the superimposition of a light distribution pattern. It is a figure for demonstrating the superimposition of a light distribution pattern. It is a schematic diagram for demonstrating the vehicle lamp unit of 2nd embodiment. It is a figure for demonstrating the principle by which the brightness of the irradiation light of the lamp unit for vehicles of 2nd embodiment is switched.

  Embodiments of the present invention will be described below with reference to the drawings.

<First embodiment>
Drawing 1 is a mimetic diagram for explaining a vehicular lamp unit (vehicle headlamp unit) of a first embodiment. The vehicle lamp unit 100a according to the first embodiment accommodates a light source 1a, a parallel optical system 2, a polarizing beam splitter 3a, a reflecting mirror 4, a reflective liquid crystal element (light control means) 5a, a projection optical system 6a, and these. The lamp unit housing 7 is included.

  The vehicle lamp unit 100a is configured to form a light distribution pattern according to the position of a forward vehicle or the like existing in front of the host vehicle under the control of the lighting control device 200. The lighting control device 200 is a camera that captures the front of the host vehicle, an image processing unit that detects the position of the front vehicle based on an image obtained by the camera, and a position of the front vehicle that is detected by the image processing unit. And a control unit for setting the light irradiation range and driving the vehicle lamp unit 100a. A vehicle headlamp system is configured to include the vehicle lamp unit 100a and the lighting control device 200 (the same applies to other embodiments).

  The light source 1a emits white light, and is, for example, a white light LED configured by combining a yellow phosphor with a light emitting element (LED) that emits blue light. As the light source 1a, in addition to the LED, a laser, and a light source generally used for a vehicle lamp unit such as a light bulb or a discharge lamp can be used.

  The parallel optical system 2 converts the light emitted from the light source 1a into parallel light. For example, a convex lens can be used. In this case, parallel light can be created by arranging the light source 1a near the focal point of the convex lens. As the parallel optical system 2, a lens, a reflecting mirror, or a combination of them can be used (the same applies to other embodiments).

  The polarization beam splitter 3a separates the light emitted from the parallel optical system 2 into two P-waves and S-waves having different polarization directions, and the lower side (first side) and right side (first side) in the figure. The light is emitted from each of the two surfaces. As the polarizing beam splitter 3a, for example, a wire grid type having a wide wavelength region can be used. An example of such a polarizing beam splitter 3a is a type in which a wire grid polarizer is bonded and fixed between two right-angle prisms (for example, a wire grid cube type polarizing beam splitter manufactured by Edmund Optics).

  The reflecting mirror 4 is disposed so as to face the right side surface of the polarizing beam splitter 3a, and reflects the light emitted from the right side surface by bending it by approximately 90 degrees. As the reflecting mirror 4, for example, a plane mirror in which silver is vapor-deposited on the surface of a glass substrate can be used. In this case, the reflecting mirror 4 is arranged so that the surface thereof forms an angle of approximately 45 degrees with respect to the path (optical axis) of the light emitted from the right side surface of the polarizing beam splitter 3a (in other embodiments). The same).

  The reflective liquid crystal element 5a includes a first region 51 where light emitted from the lower side surface of the polarizing beam splitter 3a is incident, and a second region where light emitted from the right side surface of the polarizing beam splitter 3a and reflected by the reflecting mirror 4 is incident. The first region 51 and the second region 52 are reflected without rotating the polarization direction of the incident light (first state) or reflected by rotating the polarization direction. (Second state). The first state and the second state in the reflective liquid crystal element 5a can be switched for each predetermined section (pixel) according to the magnitude of the voltage applied to the liquid crystal layer given by the lighting control device 200. The reflective liquid crystal element 5a includes, for example, a liquid crystal layer disposed between upper and lower substrates, and a 45 degree twist twist in which the liquid crystal molecules of the liquid crystal layer are horizontally aligned by twisting 45 degrees between the upper substrate and the lower substrate. A nematic (TN) liquid crystal element can be used. A reflective film made of aluminum is provided on the outside (or inside) of the back side substrate of the reflective liquid crystal element 5a.

  Here, the reason why the TN liquid crystal element is used as the reflective liquid crystal element 5a is that the liquid crystal molecules are twist-oriented to reflect the light by rotating the polarization direction of a wide wavelength band by 90 degrees. The reflective liquid crystal element 5a can reflect the polarized light from the polarization beam splitter 3a by rotating it approximately 90 degrees when no voltage is applied to the liquid crystal layer, and can reflect the polarized light without rotating when a voltage is applied. These two states can be switched based on a signal (applied voltage to the liquid crystal element) received from the lighting control device 200.

  The projection optical system 6 a is reflected by the first region 51 of the reflective liquid crystal element 5 a and again passes through the polarization beam splitter 3 a, and is reflected by the second region 52 of the reflective liquid crystal element 5 a and reflected by the reflecting mirror 4. The light reflected and again passed through the polarization beam splitter 3a is spread so as to be a predetermined headlight light distribution and projected to the front of the host vehicle, and an appropriately designed lens is used. As the projection optical system 6a, a lens, a reflecting mirror, or a combination thereof can be used (the same applies to other embodiments).

  FIG. 2 is a diagram for explaining the principle of switching the brightness of the irradiation light of the vehicle lamp unit of the first embodiment. Here, the polarization beam splitter 3a and the reflective liquid crystal element 5a are extracted from the constituent members of the vehicular lamp unit 100a, and the principle by which the brightness of the irradiated light is switched by these will be described.

  Since the parallel light incident on the polarization beam splitter 3a is non-polarized light, it has both P wave and S wave components. This parallel light passes straight through the wire grid polarizer 8a, which is a polarization separation part of the polarization beam splitter 3a, and is emitted from the right side surface of the polarization beam splitter 3a, and reflected by a 90 degree angle (advancing light). Direction) is changed to be separated into S waves that are emitted from the lower surface of the polarizing beam splitter 3a and enter the reflective liquid crystal element 5a.

  When no voltage is applied to the reflective liquid crystal element 5a, the S wave incident on the first region 51 of the reflective liquid crystal element 5a reciprocates through the liquid crystal layer, thereby rotating the polarization direction by 90 degrees to become a P wave. The light is emitted from the reflective liquid crystal element 5a and again enters the polarization beam splitter 3a. The P wave incident on the polarization beam splitter 3a passes straight through the wire grid polarizer 8a. Thus, when no voltage is applied to the reflective liquid crystal element 5a, the light irradiated through the projection optical system 6a is in a bright state.

  Further, when a voltage is applied to the reflective liquid crystal element 5a, the S wave incident on the first region 51 of the reflective liquid crystal element 5a is reflected as an S wave without changing the polarization direction even if it passes back and forth through the liquid crystal layer. The light exits from the element 5a and enters the polarization beam splitter 3a again. The S wave incident on the polarization beam splitter 3a changes its angle by 90 degrees (light traveling direction) due to reflection at the wire grid polarizer 8a, and returns to the light source 1a side. Thus, when a voltage is applied to the reflective liquid crystal element 5a, the light irradiated through the projection optical system 6a is in a dark state.

  On the other hand, when no voltage is applied to the reflective liquid crystal element 5a, the P wave incident on the second region 52 of the reflective liquid crystal element 5a passes through the liquid crystal layer, so that the polarization direction is rotated by 90 degrees and reflected as an S wave. The light is emitted from the type liquid crystal element 5a, reflected by the reflecting mirror 4, and then enters the polarizing beam splitter 3a again. The S wave incident on the polarizing beam splitter 3a changes its angle by 90 degrees (light traveling direction) due to reflection at the wire grid polarizer 8a, and is emitted from the polarizing beam splitter 3a as irradiation light. Thus, when no voltage is applied to the reflective liquid crystal element 5a, the light irradiated through the projection optical system 6a is in a bright state.

  In addition, when a voltage is applied to the reflective liquid crystal element 5a, the P wave incident on the second region 52 of the reflective liquid crystal element 5a does not change the polarization direction even when passing through the liquid crystal layer, and the P wave does not change from the reflective liquid crystal element 5a. After being emitted and reflected by the reflecting mirror 4, it enters the polarizing beam splitter 3 a again. The P wave incident on the polarization beam splitter 3a passes straight through the wire grid polarizer 8a and returns to the light source 1a side. Thus, when a voltage is applied to the reflective liquid crystal element 5a, the light irradiated through the projection optical system 6a is in a dark state.

  The outgoing light reflected by each of the first region 51 and the second region 52 of the reflective liquid crystal element 5a is added by the polarization beam splitter 3a. At this time, a desired light distribution pattern is formed by controlling the polarization direction of the emitted light for each pixel (predetermined section) of the reflective liquid crystal element 5a. For example, if the light distribution pattern of the emitted light in each of the first region 51 and the second region 52 of the reflective liquid crystal element 5a is exactly the same, and the light distribution patterns are overlapped at the same position, the light use efficiency can be improved. A vehicle lamp unit with high contrast between light and dark can be realized. An example of the light distribution pattern (light / dark pattern) in this case is shown in FIG. 3A is an example of a light distribution pattern by the first region 51 of the reflective liquid crystal element 5a, FIG. 3B is an example of a light distribution pattern by the second region 52 of the reflective liquid crystal element 5a, and FIG. It is a figure which shows the example of a synthetic light distribution pattern.

  In addition, the light distribution patterns of the emitted light in the first region 51 and the second region 52 of the reflective liquid crystal element 5a are made different and overlapped at the same position, or the light distribution patterns are arranged using the same light distribution pattern. If the positions of the light patterns are shifted and overlapped, the reflected light patterns of the light that is the brightest when the light from each light distribution pattern is added, and the light that is intermediate brightness from only one pattern are both It is possible to realize a vehicle lamp unit that can control three types of brightness of the darkest part that does not reach. An example of the light distribution pattern (light / dark pattern) in this case is shown in FIG. 4A shows an example of a light distribution pattern by the first region 51 of the reflective liquid crystal element 5a, FIG. 4B shows an example of a light distribution pattern by the second region 52 of the reflective liquid crystal element 5a, and FIG. It is a figure which shows the example of a synthetic light distribution pattern.

<Second embodiment>
FIG. 5 is a schematic diagram for explaining the vehicular lamp unit of the second embodiment. A vehicle lamp unit 100b according to the second embodiment includes a light source 1b, a parallel optical system 2, a polarizing beam splitter 3b, a reflecting mirror 4, a reflective liquid crystal element 5b, a projection optical system 6b, a phosphor 9, and a lamp unit that accommodates these. A housing 7 is included. The vehicle lamp unit 100b is configured to form a light distribution pattern according to the position of a forward vehicle or the like existing in front of the host vehicle under the control of the lighting control device 200.

  The light source 1b emits light having a single wavelength, and is a light emitting element (LED) that emits blue light, for example.

  The parallel optical system 2 converts single-wavelength light emitted from the light source 1b into parallel light. For example, a convex lens can be used. In this case, parallel light can be created by disposing the light source 1b near the focal point of the convex lens.

  The polarization beam splitter 3b separates the outgoing light from the parallel optical system 2 into two light beams having different polarization directions, the P wave and the S wave, and the lower side surface (first surface) and the right side surface (first surface) in the figure. The light is emitted from each of the two surfaces. As the polarization beam splitter 3b, for example, a material using a dielectric multilayer film corresponding to the wavelength band of the light source 1b can be used. Examples of such a polarizing beam splitter 3b include a polarizing beam splitter manufactured by Sigma Kogyo Co., Ltd.

  The reflecting mirror 4 is disposed so as to face the right side surface of the polarizing beam splitter 3b, and reflects the light emitted from the right side surface by bending it by approximately 90 degrees.

  The reflective liquid crystal element 5b includes a first region 53 where light emitted from the lower side surface of the polarizing beam splitter 3b is incident, and a second region where light emitted from the right side surface of the polarizing beam splitter 3b and reflected by the reflecting mirror 4 is incident. The first region 53 and the second region 54 are reflected without rotating the polarization direction of the incident light (first state), or reflected by rotating the polarization direction. (Second state). The first state and the second state in the reflective liquid crystal element 5b can be switched for each predetermined section (pixel) according to the magnitude of the voltage applied to the liquid crystal layer given by the lighting control device 200. As the reflective liquid crystal element 5b, for example, a liquid crystal element that includes an upper and lower substrate and a liquid crystal layer sandwiched therebetween and in which liquid crystal molecules of the liquid crystal layer are uniaxially aligned vertically between the upper substrate and the lower substrate can be used. . A reflective film made of aluminum is provided on the outside (or inside) of the back side substrate of the reflective liquid crystal element 5b.

  Here, the reason why the vertical alignment type liquid crystal element is used as the reflection type liquid crystal element 5b is that the retardation when no voltage is applied to the liquid crystal layer is zero, so that the incident polarized light is not changed at all (the polarization direction). This is because the dark state of the illumination light can be made the darkest because the light is reflected and emitted (without rotating the light). Further, when a voltage is applied to the liquid crystal layer, the incident polarized light is rotated by 90 degrees and reflected and emitted, so that a bright state of illumination light can be created. These two states can be switched based on a signal (applied voltage to the liquid crystal element) received from the lighting control device 200. Polarization can be rotated 90 degrees by adjusting the retardation of the reflective liquid crystal element 5b, which is a vertical alignment type, to a quarter wavelength, but the value varies depending on the wavelength of incident light, that is, has wavelength dependence. Yes. However, in this embodiment, since a light source that emits light of a single wavelength is used as the light source 1b, it is not necessary to consider wavelength dependency.

  The phosphor 9 is arranged so that outgoing light from the upper side surface of the polarizing beam splitter 3b is incident, and light having a wavelength different from the single wavelength light generated by excitation by the incident single wavelength light ( (Fluorescence). As the phosphor 9, for example, a phosphor plate obtained by mixing and baking a YAG phosphor and a scattering substance, or a transparent substrate coated with a phosphor substance can be used. A part of the single wavelength light (blue light) reflected from the reflective liquid crystal element 5b and passing through the polarizing beam splitter 3b again excites the phosphor 9 to emit yellow light, and the remaining blue light is fluorescent as it is. The body 9 is emitted. At this time, yellow light becomes scattered light from the phosphor 9, blue light also becomes scattered light by the scattering material, and they are mixed and emitted from the phosphor 9 as white scattered light.

  The projection optical system 6b spreads the scattered light that has passed through the phosphor 9 so as to be a predetermined light distribution for headlights and projects it forward of the host vehicle, and an appropriately designed lens is used.

  FIG. 6 is a diagram for explaining the principle of switching the brightness of the irradiation light of the vehicle lamp unit according to the second embodiment. Here, the polarization beam splitter 3b, the reflective liquid crystal element 5b, and the phosphor 9 are extracted from the constituent members of the vehicle lamp unit 100b, and the principle by which the brightness of the irradiated light is switched by these will be described.

  Since the parallel light incident on the polarization beam splitter 3b is non-polarized light, it has both P-wave and S-wave components. The parallel light passes straight through the dielectric multilayer film 8b, which is a polarization separation portion of the polarization beam splitter 3b, and exits from the right side surface of the polarization beam splitter 3b. Direction) is changed and separated into S-waves which are emitted from the lower surface side of the polarization beam splitter 3b and enter the reflective liquid crystal element 5b.

  When no voltage is applied to the reflective liquid crystal element 5b, the S wave incident on the first region 53 of the reflective liquid crystal element 5b is reflected as an S wave without changing the polarization direction even if it passes back and forth through the liquid crystal layer. The light is emitted from 5b and again enters the polarization beam splitter 3b. The S wave incident on the polarization beam splitter 3b changes its angle by 90 degrees (light traveling direction) due to reflection in the dielectric multilayer film 8b which is a polarization separation portion, and returns to the light source 1b side. Thus, when no voltage is applied to the reflective liquid crystal element 5b, the light irradiated through the projection optical system 6b is in a dark state.

  Further, when a voltage is applied to the reflective liquid crystal element 5b, the S wave incident on the first region 53 of the reflective liquid crystal element 5b passes through the liquid crystal layer so that the polarization direction is rotated by 90 degrees to become a P wave. The light is emitted from the liquid crystal element 5b and again enters the polarization beam splitter 3b. The P wave incident on the polarization beam splitter 3b passes straight through the dielectric multilayer film 8b and is emitted from the upper side surface of the polarization beam splitter 3b. Thus, when a voltage is applied to the reflective liquid crystal element 5b, the light irradiated through the projection optical system 6b becomes bright.

  On the other hand, when no voltage is applied to the reflective liquid crystal element 5b, the P wave incident on the second region 54 of the reflective liquid crystal element 5b is reflected as a P wave without changing the polarization direction even if it passes back and forth through the liquid crystal layer. The light is emitted from the liquid crystal element 5b, reflected by the reflecting mirror 4, and then enters the polarizing beam splitter 3b again. The P wave incident on the polarization beam splitter 3b passes straight through the dielectric multilayer film 8b, which is a polarization separation portion, and returns to the light source 1b side. Thus, when no voltage is applied to the reflective liquid crystal element 5b, the light irradiated through the projection optical system 6b is in a dark state.

  In addition, when a voltage is applied to the reflective liquid crystal element 5b, the P wave incident on the second region 54 of the reflective liquid crystal element 5b passes through the liquid crystal layer, so that the polarization direction rotates 90 degrees and becomes an S wave. The light is emitted from the liquid crystal element 5b, reflected by the reflecting mirror 4, and then enters the polarizing beam splitter 3b again. The S wave incident on the polarization beam splitter 3b changes its angle by 90 degrees (light traveling direction) due to reflection at the dielectric multilayer film 8b, and is emitted from the upper side surface of the polarization beam splitter 3b. Thus, when a voltage is applied to the reflective liquid crystal element 5b, the light irradiated through the projection optical system 6b becomes bright.

  The outgoing light reflected by each of the first region 53 and the second region 54 of the reflective liquid crystal element 5b is added by the polarization beam splitter 3b. At this time, a desired light distribution pattern is formed by controlling the polarization direction of the emitted light for each pixel (predetermined section) of the reflective liquid crystal element 5b. For example, if the light distribution pattern of the emitted light in each of the first region 53 and the second region 54 of the reflective liquid crystal element 5b is exactly the same and the light distribution patterns are overlapped at the same position, the light use efficiency can be improved. A vehicle lamp unit having high contrast between light and dark can be realized (see FIGS. 3A, 3B, and 3C).

  Further, the light distribution patterns of the emitted light in the first region 53 and the second region 54 of the reflective liquid crystal element 5b are made different from each other and overlapped at the same position, or are distributed using the same light distribution pattern. If the positions of the light patterns are shifted and overlapped, the reflected light patterns of the light that is the brightest when the light from each light distribution pattern is added, and the light that is intermediate brightness from only one pattern are both A vehicular lamp unit that can control three types of brightness of the darkest part that does not reach can be realized (see FIGS. 4A, 4B, and 4C).

  According to each embodiment as described above, a vehicle lamp unit and a vehicle headlamp system can be obtained that have a high contrast ratio of bright and dark light and can sufficiently cut off illumination. In addition, since any two light beams having different polarization directions emitted from the polarization beam splitter can be used for illumination, the light use efficiency can be further increased. Furthermore, since control of two lights having different polarization directions can be realized by using one reflective liquid crystal element, a cost reduction effect can be obtained.

  In addition, this invention is not limited to the content of embodiment mentioned above, In the range of the summary of this invention, it can change and implement variously. For example, in each of the above-described embodiments, the control of the reflective liquid crystal element uses only a binary voltage such as voltage application and no voltage application. However, by setting the voltage to be applied more finely, the reflectance of incident light is set. Can be changed continuously. Thereby, the vehicle lamp unit and the vehicle headlamp system in which the brightness is freely set for each irradiation region can be realized. In the above-described embodiment, the light control means including one reflective liquid crystal element is used to perform light control in the first area and the second area. However, the light control means including two reflective liquid crystal elements is used. The light control corresponding to the first area may be performed on the one hand and the light control corresponding to the second area may be performed on the other hand.

DESCRIPTION OF SYMBOLS 1a, 1b: Light source 2: Parallel optical system 3a, 3b: Polarization beam splitter 4: Reflection mirror 5a, 5b: Reflective type liquid crystal element 6a, 6b: Projection optical system 7: Lamp unit housing | casing 8a: Wire grid polarizer 8b: Dielectric multilayer film 9: Phosphor 51, 53: First region 52, 54: Second region 100a, 100b: Vehicle lamp unit 200: Lighting control device

Claims (5)

A vehicle headlamp unit for selectively illuminating the front of the host vehicle,
A light source;
A collimating optical system that collimates light from the light source;
It has a first surface and a second surface, and separates the light emitted from the parallel optical system into two lights whose polarization directions are orthogonal to each other, and is emitted from each of the first surface and the second surface A polarizing beam splitter,
A reflecting mirror disposed opposite to the second surface of the polarizing beam splitter;
In each of a first region where light emitted from the first surface of the polarizing beam splitter is incident and a second region where light emitted from the second surface of the polarizing beam splitter and reflected by the reflecting mirror is incident A reflective liquid crystal element capable of switching, for each predetermined section, a first state in which incident light is reflected without rotating the polarization direction and a second state in which the polarization direction is rotated and reflected;
The light reflected by the first region of the reflective liquid crystal element and again passed through the polarization beam splitter, and reflected by the second region of the reflective liquid crystal element and reflected by the reflecting mirror and re-polarized. A projection optical system that projects light that has passed through a beam splitter to the front of the host vehicle;
Including a vehicle headlamp unit. A vehicle headlamp unit for selectively illuminating the front of the host vehicle,
A light source that emits light of a first wavelength that is a single wavelength;
A collimating optical system that collimates light from the light source;
It has a first surface and a second surface, and separates the light emitted from the parallel optical system into two lights whose polarization directions are orthogonal to each other, and is emitted from each of the first surface and the second surface A polarizing beam splitter,
A reflecting mirror disposed opposite to the second surface of the polarizing beam splitter;
In each of a first region where light emitted from the first surface of the polarizing beam splitter is incident and a second region where light emitted from the second surface of the polarizing beam splitter and reflected by the reflecting mirror is incident A reflective liquid crystal element capable of switching, for each predetermined section, a first state in which incident light is reflected without rotating the polarization direction and a second state in which the polarization direction is rotated and reflected;
The light reflected by the first region of the reflective liquid crystal element and again passed through the polarization beam splitter, and reflected by the second region of the reflective liquid crystal element, reflected by the reflecting mirror, and again A phosphor that emits fluorescence having a second wavelength different from the first wavelength by being excited by each of the light that has passed through the polarization beam splitter;
A projection optical system that projects the mixed color light of the fluorescence from the phosphor and the light that has passed through the phosphor to the front of the host vehicle;
Including a vehicle headlamp unit. The light distribution pattern in each of the first region and the second region of the reflective liquid crystal element is the same, and is synthesized by the polarization beam splitter so that the same light distribution pattern overlaps each other.
The vehicle headlamp unit according to claim 1 or 2. The light distribution pattern in each of the first region and the second region of the reflective liquid crystal element is different, and is synthesized by the polarization beam splitter so that the different light distribution patterns overlap each other.
The vehicle headlamp unit according to claim 1 or 2.   A vehicle headlamp system comprising: the vehicle headlamp unit according to any one of claims 1 to 4; and a lighting control device that controls the operation of the vehicle headlamp unit.

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