Vehicle projection device

Abstract

To provide a vehicle projection device capable of improving utilization efficiency of light.SOLUTION: A vehicle projection device 1 according to the embodiment comprises: a plurality of projectors 30 projecting an image; and a light source unit 10 supplying light to the plurality of projectors 30. The light source unit 10 includes: a laser light source 11 emitting a laser beam with a first polarization component; a polarization rotation unit 12 rotating the polarization direction of the laser beam emitted from the laser light source 11; and a branch part 14 branching a laser beam passing through the polarization rotation unit 12 into the first polarization component and a second polarization component other than the first polarization component and supplying it to each of the plurality of projectors 30.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a projection device for a vehicle. [Background technology]

[0002] Conventionally, Patent Document 1 discloses a technique in which laser light emitted from a laser light source is split into multiple directions and used as light sources in different locations. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-207390 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology disclosed in Patent Document 1 splits the laser light and then adjusts the brightness of each split laser light. As a result, the laser light with reduced brightness is wasted, resulting in inefficient use of the laser light emitted from the light source.

[0005] The present disclosure has been made in consideration of the above circumstances, and has an object to provide a vehicle projection device that can improve light utilization efficiency. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the vehicle projection device of the present disclosure includes a plurality of projection units that project images and a light source unit that supplies light to the plurality of projection units, and the light source unit has a laser light source that emits laser light of a first polarization component, a polarization rotation unit that rotates the polarization direction of the laser light emitted from the laser light source, and a branching unit that branches the laser light that passes through the polarization rotation unit into the first polarization component and a second polarization component other than the first polarization component and supplies them to each of the plurality of projection units. [Effects of the Invention]

[0007] The vehicle projection device of the present disclosure can improve the light utilization efficiency. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is an explanatory diagram conceptually showing a vehicle projection device according to an embodiment of the present invention mounted on a vehicle; [Figure 2] FIG. 2 is a schematic functional block diagram showing the functional configuration of the vehicle projection device. [Figure 3] FIG. 10 is a schematic functional block diagram showing the functional configuration of a projection device as a first modified example. [Figure 4] FIG. 10 is a schematic functional block diagram showing the functional configuration of a projection device as a second modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of a vehicle projection device according to the present disclosure will be described with reference to the accompanying drawings. The vehicle projection device according to the present disclosure can be applied to any vehicle, such as an automobile, a motorcycle, agricultural machinery, or construction machinery. In this embodiment, an example in which the vehicle projection device is mounted on an automobile will be described.

[0010] FIG. 1 is an explanatory diagram conceptually showing a vehicle projection device 1 according to this embodiment that is mounted on a vehicle 2. As shown in FIG.

[0011] FIG. 2 is a schematic functional block diagram showing the functional configuration of the vehicle projection device 1. As shown in FIG.

[0012] In the following description, "front," "rear," "top," and "bottom" follow the definitions of "Fr.", "Re.", "To.", and "Bo." in FIG.

[0013] The vehicle projection device 1 (hereinafter referred to as "projection device 1") includes a light source unit 10, an optical fiber 20, and a projector 30 (projection unit).

[0014] The light source unit 10 supplies light to multiple projectors 30. The light source unit 10 has a laser light source 11, a polarization rotation unit 12, a branching unit 13, and a control unit 14. The laser light source 11, the polarization rotation unit 12, the branching unit 13, and the control unit 14 are housed in a single housing, which is disposed in, for example, the rear trunk 3 of the vehicle 2.

[0015] The laser light source 11 emits a laser beam that is a linearly polarized P-polarized light as a first polarization component. The laser light source 11 may be a single (single color) or multiple (multiple colors) laser light source, for example, three light sources for RGB.

[0016] Polarization rotation unit 12 rotates the polarization direction of the laser light emitted from laser light source 11. Specifically, polarization rotation unit 12 rotates P-polarized laser light to convert it into S-polarized laser light. Polarization rotation unit 12 is, for example, a liquid crystal polarization rotator that rotates the incident polarized light to a desired angle by electrically controlling liquid crystal. Note that polarization rotation unit 12 may also be a wave plate that is mechanically controlled to rotate polarized light.

[0017] The branching unit 13 branches the laser light passing through the polarization rotation unit 12 into P-polarized light (first polarization component) and S-polarized light (second polarization component other than the first polarization component) in order to supply the laser light to multiple projectors 30. Specifically, the branching unit 13 reflects (or transmits) the P-polarized light and transmits (or reflects) the S-polarized light, thereby branching the laser light and supplying it in two directions. The branching unit 13 is, for example, a polarizing beam splitter.

[0018] The control unit 14 is a control board that controls the laser light source 11 and the polarization rotation unit 12. The control unit 14 controls, for example, whether or not the laser light source 11 emits light, the brightness, and the amount of rotation of the polarization rotation unit 12.

[0019] Specifically, control unit 14 controls polarization rotation unit 12 not to rotate the polarization direction of the laser light (rotate it by 0 degrees), thereby causing the P-polarized laser light emitted from laser light source 11 to be emitted as is from polarization rotation unit 12. Control unit 14 also controls polarization rotation unit 12 to rotate the polarization direction of the laser light by 90 degrees, thereby converting the P-polarized laser light emitted from laser light source 11 into S-polarized laser light and causing it to be emitted from polarization rotation unit 12. In this way, control unit 14 controls the laser light heading toward branching unit 13, thereby controlling whether or not the laser light emitted from laser light source 11 is branched.

[0020] Furthermore, the control unit 14 controls the ratio of the brightness of the P-polarized light to the S-polarized light by controlling the polarization rotation unit 12 to convert the polarization direction to a desired angle. For example, the control unit 14 controls the polarization rotation unit 12 to rotate the polarization direction of the laser light by 45 degrees, causing the polarization rotation unit 12 to emit laser light in which the brightness ratio of the P-polarized light to the S-polarized light is 50:50. In this way, by controlling the polarization rotation unit 12, the control unit 14 can arbitrarily control the ratio of the brightness of the P-polarized light to the S-polarized light, such as 30:70 or 60:40. As a result, in cases where two projectors 30 project images to different projection locations, the control unit 14 can control the ratio of the P-polarized light component to the S-polarized light component depending on the brightness of the projection location.

[0021] The optical fibers 20 are two optical fibers 20 provided so that the light source unit 10 can supply laser light, which is branched light, to each projector 30. The laser light from the branching unit 13 is coupled by a required optical element and guided to the optical fibers 20. The optical fibers 20 have a required length depending on where the projectors 30 are installed, and are wired inside the vehicle 2 so as not to be visible to passengers, etc.

[0022] The projector 30 is made up of two (or more) projectors, a ceiling projector 30a and an instrument panel projector 30b, which project an image onto a projection destination. The projector 30 uses laser light guided by an optical fiber 20 as a light source to generate display light L relating to the image, and emits the display light L to a required location. The projector 30 has required optical members, a display, a control unit, and a case.

[0023] The optical members diffuse the laser light supplied from the light source unit 10 and correct distortion of the display light L emitted from the display. The display is, for example, a TFT (Thin Film Transistor), a DMD (Digital Micromirror Device), or a GOBO projector. The control unit is a control board that controls the display to generate the required display light L. The case houses the optical members, the display, and the control unit, and emits the display light L to the projection destination.

[0024] The ceiling projector 30a is disposed between the driver's seat and the passenger's seat so as to project the display light L onto the ceiling 4. The instrument panel projector 30b is disposed on the ceiling 4 so as to project the display light L onto the instrument panel 5.

[0025] As shown in FIG. 1, the projection device 1 projects display light L from one or both of a ceiling projector 30a and an instrument panel projector 30b according to predetermined conditions.

[0026] For example, during manual driving, the projection device 1 uses the instrument panel projector 30b to display vehicle information necessary for driving on the instrument panel 5. Specifically, the projection device 1 supplies only P-polarized light from the light source unit 10 to the instrument panel projector 30b without rotating the polarization direction of the laser light, and displays an image on the instrument panel 5.

[0027] On the other hand, during autonomous driving or when the vehicle is stopped, the projection device 1 displays entertainment images on the instrument panel 5 and the ceiling 4 using the instrument panel projector 30b and the ceiling projector 30a. Specifically, the projection device 1 rotates the polarization direction of the laser light by 45 degrees and supplies P-polarized light to the instrument panel projector 30b and S-polarized light to the ceiling projector 30a from the light source unit 10, respectively, to display images on the instrument panel 5 and the ceiling 4. At this time, if the instrument panel 5 is brighter than the ceiling 4 and the display light L emitted from the instrument panel projector 30b requires brightness, the projection device 1 controls the polarization rotation unit 12 so that the brightness of the P-polarized light is greater than the brightness of the S-polarized light, thereby increasing the amount of P-polarized light and maintaining the visibility of the image projected on the instrument panel 5.

[0028] The projection device 1 of this embodiment can use the light from the light source without loss when selectively projecting images onto a plurality of projection destinations, thereby improving the light utilization efficiency.

[0029] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims.

[0030] For example, Fig. 3 is a schematic functional block diagram showing the functional configuration of a projection device 1 as a first modified example. If it is desired to increase the brightness of the laser light source 11, the light source unit 10 may have two laser light sources, first and second laser light sources 11a and 11b, and two polarization rotation units 12a and 12b. In this case, the first laser light source 11a may emit P-polarized light, which may pass through the first polarization rotation unit 12a as P-polarized light and be reflected (or transmitted) by the branching unit 13. The second laser light source 11b may emit S-polarized light, which may pass through the second polarization rotation unit 12b as S-polarized light and be transmitted (or reflected) by the branching unit 13 in the same direction as the laser light from the first laser light source 11a is reflected. This makes it possible to obtain brightness equal to the sum of the brightness of the first laser light source 11a and the brightness of the second laser light source 11b.

[0031] 4 is a schematic functional block diagram showing the functional configuration of a projection device 1 as a second modified example. If it is desired to further increase the number of projectors 30, a second polarization rotation unit 12b can be arranged downstream of the branching unit 13a (at the end of one of the laser beams branched by the branching unit 13) to rotate the polarization direction of the laser beam, and a second branching unit 13b can be arranged further downstream to branch the laser beam, thereby obtaining two or more branched beams from the branched beam of the branching unit 13a. In the polarization rotation unit 12b and the second polarization rotation unit 12b, the ratio of S-polarized light to P-polarized light can be adjusted as desired, and the distribution ratio of the light amount of the laser beam distributed by the branching unit 13a and the branching unit 13b can be adjusted as desired. In other words, the light amount of each projector 30 can be adjusted as desired depending on the installation location.

[0032] The arrangement and projection destination of the multiple projectors 30 are not limited to those described above, and may be selected from any location inside or outside the vehicle 2. For example, each projector 30 may be arranged in the middle of the rear seats of the vehicle 2 and project an image onto the ceiling 4. Alternatively, each projector 30 may be arranged on the ceiling 4 behind the rear seats and project an image onto a screen separately provided between the front and rear seats. Furthermore, each projector 30 may be arranged on the front and rear bumpers and inside the side mirrors of the vehicle 2 and project an image onto the road surface consisting of a warning or message intended for other vehicles, pedestrians, and passengers of the vehicle 2 located around the vehicle 2.

[0033] Furthermore, the multiple projectors 30 may be arranged together on the ceiling 4 of the vehicle 2 and project images adjacently onto the instrument panel 5. In this case, for example, during the daytime or evening when the surroundings are bright, brightness is required for the display light L, so laser light may be supplied to one projector 30 without branching the laser light, and an image may be projected by the single projector 30. On the other hand, during the night when the surroundings are dark, brightness is not required for the display light L compared to daytime, etc., so laser light may be branched and supplied to multiple projectors 30, and an image may be projected over a wide area by the multiple projectors 30.

[0034] Furthermore, if the light source unit 10 and the multiple projectors 30 can be arranged in close proximity, the laser light emitted from the light source unit 10 may be supplied directly to each projector 30 without guiding the laser light through the optical fiber 20.

[0035] Although the projection unit is explained as a projector 30, it may be a microlens array capable of displaying a floating image. The projection unit may also be a projector that projects an image by irradiating a laser beam onto a MEMS mirror and scanning it.

[0036] Furthermore, although an example has been described in which the first polarization component is P polarization and the second polarization component, which is a component other than the first polarization component, is S polarization, other polarization components may be used as the first polarization component and the second polarization component without being limited to this. [Explanation of symbols]

[0037] 1 Vehicle projection device (projection device) 2 vehicles 3 Rear trunk 4. Ceiling 5. Instrument panel 10 Light source unit 11, 11a, 11b Laser light source 12, 12b Polarization rotation unit 13, 13a, 13b Branch 14 Control Unit 20. Optical Fiber 30 Projector (projection unit) 30a Ceiling Projector 30b Instrument panel projector L display light

Claims

1. a plurality of projection units for projecting images; a light source unit that supplies light to the plurality of projection units, The light source unit is a laser light source that emits laser light of a first polarization component; a polarization rotation unit that rotates the polarization direction of the laser light emitted from the laser light source; a branching section that branches the laser light passing through the polarization rotation section into the first polarization component and a second polarization component other than the first polarization component and supplies the components to each of the plurality of projection units.

2. The projection device for a vehicle according to claim 1 , wherein the splitter splits the laser light by reflecting or transmitting the first polarized component and by reflecting or transmitting the second polarized component.

3. The vehicle projection device according to claim 1 , wherein the light source unit supplies the laser light to each of the plurality of projection units via an optical fiber.

4. 2. The projection device for a vehicle according to claim 1, further comprising a control unit that controls the polarization rotation unit to control whether or not the laser light is branched.

5. 2. The projection device for a vehicle according to claim 1, further comprising a control unit that controls the polarization rotation unit to control a ratio between the first polarization component and the second polarization component of the laser light.

6. the plurality of projection units project images onto different projection locations; The projection device for a vehicle according to claim 5 , wherein the control unit controls a ratio between the first polarized light component and the second polarized light component in accordance with brightness of the projection location.

Images