JP2016058412A - Laser output device and output adjustment method of laser output device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser output device capable of increasing the dynamic range of laser light emitted.SOLUTION: A λ/2 wavelength plate 13 for converting the polarization direction of laser light is arranged on the optical path of laser light emitted from a light source 11, a polarization control element 142 for controlling the polarization direction of laser light is arranged on the optical path of laser light emitted from the λ/2 wavelength plate 13, an emission side polarization plate 143 is arranged on the optical path of laser light emitted from the polarization control element 142, the λ/2 wavelength plate 13 converts the polarization direction of incident laser light to become a polarization direction where the optical intensity of laser light emitted from a laser output device 10 takes an extreme value when the polarization control element 142 is turned on or off, or a polarization direction where the difference of the optical intensity of laser light emitted from the laser output device 10 takes an extreme value when the polarization control element 142 is turned on or off.SELECTED DRAWING: Figure 3

Description

The present invention relates to a laser output device that outputs laser light for generating an image by two-dimensional scanning, and an output adjustment method for the laser output device.

For example, Patent Document 1 discloses a laser scanning display device that generates an image by scanning laser light two-dimensionally. In such a laser scanning display device, a laser output device outputs laser light having a desired light intensity, and a scanning unit scans the laser light two-dimensionally to generate an image on a screen. .

In particular, when a laser scanning display device is applied to a head-up display device as disclosed in Patent Document 1, a high-luminance image that can be viewed even in a bright environment and a luminance that does not make the user feel dazzling even in a dark environment. Both low images need to be displayed.

The laser scanning display device of Patent Document 1 includes a polarizing plate that transmits light in a specific polarization direction, and a polarization control element that can control the polarization direction, and the polarization control element emits laser light from a light source. The polarization direction is adjusted, and the light intensity of the laser beam transmitted through the polarizing plate is adjusted. Therefore, in a bright environment, the amount of laser light transmitted through the polarizing plate is increased, and in a dark environment, the amount of laser light transmitted through the polarizing plate is decreased, thereby reducing the light intensity of the laser light emitted to the scanning unit. The dynamic range is secured.

JP 2013-15738 A

Normally, laser light emitted from a light source is light having a substantially constant polarization direction. For this reason, the relationship between the polarization direction of the laser light emitted from the light source and the polarization direction of the polarizing plate is not constant in the work process such as assembly, and laser light with an intensity higher than expected when it is desired to reduce the emitted laser light. When the laser beam is emitted or when it is desired to increase the amount of emitted laser light, a laser beam having a light intensity below the expected level is emitted, so that there is a problem that a sufficient dynamic range is not ensured.

In view of the above-described problems, an object of the present invention is to provide a laser output device that secures a dynamic range of emitted laser light and an output adjustment method for the laser output device.

The present invention employs the following means in order to solve the above problems.
That is, a laser output device according to the first aspect of the present invention includes a light source that emits laser light, a polarization direction conversion unit that is positioned on the optical path of the laser light emitted from the light source, and that converts the polarization direction of the laser light. A polarization control element that is located on the optical path of the laser light emitted from the polarization direction conversion unit and controls the polarization direction of the laser light, and a polarizing plate that is located on the optical path of the laser light emitted from the polarization control element, In the laser output device comprising: the polarization direction converter, the polarization direction in which the light intensity of the laser light emitted from the laser output device takes an extreme value when the polarization control element is turned on or off, or the When the polarization control element is turned on and off, the polarization direction of the laser light incident in the polarization direction where the difference in the light intensity of the laser light emitted from the laser output device takes a maximum Converting the, characterized in that.

  Further, the output adjustment method of the laser output device according to the second aspect of the present invention includes a light source that emits laser light, and polarization that is positioned on the optical path of the laser light emitted from the light source and converts the polarization direction of the laser light. A direction conversion unit, a polarization control element that controls the polarization direction of the laser light that is located on the optical path of the laser light emitted from the polarization direction conversion unit, and an optical path of the laser light that is emitted from the polarization control element In a method for adjusting the output of a laser output device comprising a polarizing plate, a laser light output step for emitting laser light to the light source, a polarization control step for turning on and / or off the polarization control element, and the polarization direction conversion A light intensity detecting step for detecting a light intensity of the laser beam emitted from the polarizing plate while adjusting a polarization direction of the laser beam emitted from the optical unit; The polarization direction of the laser light emitted from the light source is detected in the light intensity detection step by turning on and off the polarization control element, or the polarization direction in which the light intensity detected in the light intensity detection step takes an extreme value. A polarization direction adjusting step of adjusting the polarization direction so that the difference in light intensity takes a maximum value.

According to the laser output device and the output adjustment method of the laser output device of the present invention, the dynamic range of the emitted laser light can be increased.

It is a figure for demonstrating the mounting aspect of the HUD apparatus which concerns on embodiment of this invention. It is a schematic sectional drawing of the HUD apparatus of the said embodiment. It is a schematic sectional drawing of the laser output apparatus of the said embodiment. It is a figure which shows the polarization direction of the laser beam before permeate | transmitting the polarization direction conversion part of the said embodiment, and the polarization direction of the laser beam after permeate | transmitting. It is a figure which shows the electrical structure of the laser output apparatus of the said embodiment, and the electrical structure of the adjustment apparatus used for the output adjustment method of a laser output apparatus. It is a flowchart of the output adjustment method of the said embodiment. It is a figure for demonstrating the determination method of the angle of the polarization direction conversion part in the output adjustment method of the said embodiment, and is the figure which showed an example of the relationship between the angle of a polarization direction conversion part, and the light intensity of a laser beam.

Hereinafter, an embodiment in which a laser output device of the present invention is applied to a head-up display device (HUD device) will be described with reference to the drawings.

As shown in the figure, the HUD device 1 is arranged on the dashboard of the vehicle 2 and directs the display light L representing an image M (see FIG. 2) for notifying predetermined information toward the windshield (transmission reflection surface) 3. Exit. The display light L reflected by the windshield 3 is visually recognized by the observer 4 (mainly the driver of the vehicle 2) as a virtual image V of the image M formed in front of the windshield 3. In this way, the HUD device 1 causes the observer 4 to visually recognize the virtual image V of the image M.

As shown in FIG. 2, the HUD device 1 includes a laser output device 10, a scanning unit 20, a screen 30, a plane mirror 40, a concave mirror 50, and an illuminance sensor 60.

The laser output device 10 emits a synthetic laser beam C, which will be described later, mixed with laser beams of a plurality of colors toward the scanning unit 20. As shown in FIG. 3, the laser output device 10 includes a light source 11 made of a semiconductor laser, a condensing optical system 12, a polarization direction conversion unit 13, a light control unit 14, an optical axis adjustment unit 15, and a transmission. A reflection unit 16 and a light intensity detection unit 17 are included.

The light source 11 includes a light source 11a that emits red laser light R having a peak at a wavelength of about 640 nm, a light source 11b that emits green laser light G having a peak at a wavelength of about 520 nm, and a peak at a wavelength of about 450 nm. A light source 11c that emits blue laser light B having The light source 11 is supplied with a drive signal (drive current) from a laser output control unit 100 described later, and each emits light at a predetermined light intensity and timing. The red laser light R, green laser light G, and blue laser light B emitted from the light source 11 are light having linearly polarized light having a certain polarization direction, and are combined laser light C to be described later. The respective deflection directions are aligned and fixed with an adhesive or the like. Note that aligning the polarization direction does not only mean that the polarization directions of the red laser beam R, the green laser beam G, and the blue laser beam B are completely matched, but, for example, within a range of ± 5 degrees. Including aligning.

The condensing optical system 12 includes a condensing optical system 12a, a condensing optical system 12b, and a condensing optical system 12c disposed on the optical paths of the red laser light R, the green laser light G, and the blue laser light B, respectively. , And each laser beam R, G, B emitted from each light source 11 is condensed, and the spot diameter is reduced to obtain convergent light.

The polarization direction conversion unit 13 is, for example, a λ / 2 wavelength plate or the like, and rotates the polarization directions of the incident red laser light R, green laser light G, and blue laser light B. Specifically, as shown in FIG. 4, the λ / 2 wavelength plate 13 has an angle θ formed by the fast axis and the polarization direction of the incident laser beam as an angle θ, 2θ that is twice this angle θ. Only the polarization direction is rotated and emitted. The λ / 2 wavelength plate 13 has an index portion indicating a fast axis, and is assembled before output adjustment, which will be described later, with the index portion as a mark.

The light control unit 14 includes an incident-side polarizing plate 141, a polarization control element 142, and an output-side polarizing plate 143, and adjusts (controls) the amount of each of the laser beams R, G, and B that pass therethrough. . In the present embodiment, the incident side polarizing plate 141, the polarization control element 142, and the output side polarizing plate 143 are the incident side polarizing plate 141, the polarization control element 142, and the optical axis described later in the traveling direction of the laser beams R, G, and B. The adjustment unit 15 and the emission-side polarizing plate 143 are arranged in this order.

The incident-side polarizing plate 141 is configured by a reflective polarizing plate such as a wire grid polarizing plate, and is disposed on the optical path of each laser beam R, G, B emitted from the laser output device 10. The transmission axis of the incident-side polarizing plate 141 is arranged so as to be substantially in the same direction as the polarization directions of the laser beams R, G, and B when the light sources 11a, 11b, and 11c are fixed.

The polarization control element 142 is, for example, a VA (Vertical Alignment) type liquid crystal element. The VA-type liquid crystal element 142 includes two transparent substrates having transparent electrodes and a nematic liquid crystal sandwiched between the transparent electrodes and vertically aligned with negative dielectric anisotropy.

The emission side polarizing plate 143 is formed of a reflection type polarizing plate such as a wire grid polarizing plate, and is a light of a synthetic laser beam C in which the optical axes of the laser beams R, G, and B are aligned by an optical axis adjusting unit 15 described later. Located on the road. The transmission axis of the output side polarizing plate 143 is arranged in a direction orthogonal to the transmission axis of the incident side polarizing plate 141. That is, the transmission axis of the output side polarizing plate 143 is arranged in a direction substantially orthogonal to the polarization direction of the laser beams R, G, and B when the light sources 11a, 11b, and 11c are fixed.

As described above, since the transmission axis of the exit-side polarizing plate 143 is arranged so as to be orthogonal to the polarization directions of the laser beams R, G, and B, the polarization control element 142 and the exit-side polarizing plate 143 have 1 It functions as one normally black liquid crystal element. That is, when no voltage is applied to the polarization control element 142 (turning off the polarization control element 142), the laser beams R, G, and B incident on the polarization control element 142 maintain the polarization state while maintaining the polarization control element 142. Emanates from. The laser beams R, G, and B emitted from the polarization control element 142 are incident on the emission side polarizing plate 143. Since the transmission axis of the output side polarizing plate 143 is a direction orthogonal to the laser beams R, G, and B, the laser beams R, G, and B cannot pass through the output side polarizing plate 143.

On the other hand, when a voltage is applied to the polarization control element 142 (turns on the polarization control element 142), the laser light R, G, B incident on the polarization control element 142 is applied by the birefringence of the polarization control element 142. Depending on the polarization direction, the polarization direction changes and the light is emitted from the polarization control element 142. The laser beams R, G, and B emitted from the polarization control element 142 with the polarization direction changed are incident on the emission side polarizing plate 143. Since the transmission axis of the exit-side polarizing plate 143 is a direction orthogonal to the polarization direction of each of the laser beams R, G, and B before the polarization direction changes, a part of the laser beams R, G, and B whose polarization direction has changed. (Or all) is transmitted through the output-side polarizing plate 143. Since the light intensity of each of the laser beams R, G, and B that passes through the emission-side polarizing plate 143 depends on the voltage applied to the polarization control element 142, the light control unit 14 uses the light of each of the laser beams R, G, and B. The intensity can be controlled.

The optical axis adjusting unit 15 is configured to match the optical axes of the laser beams R, G, and B emitted from the light source 11 and passed through the dimming unit 14 and output the combined laser beam C as one synthetic laser beam C. . Specifically, the optical axis adjustment unit 15 includes an optical axis adjustment unit 15a that reflects light, and a dichroic mirror that reflects light of a specific wavelength but transmits light of other wavelengths. Part 15b and an optical axis adjusting part 15c.

The transmission / reflection part 16 is made of a transmissive member having a reflectivity of, for example, about 5%, and receives the combined laser light C from the output-side polarizing plate 143, and a part thereof as reflected light D, which will be described later. The light is reflected on the part 17 and most of the other part is transmitted toward the scanning part 20 described later.

The light intensity detection unit 17 includes a color sensor, a photodiode, and the like, receives the reflected light D reflected by the transmission / reflection unit 16, and detects the light intensity of each color laser light C constituting the received reflected light D. Specifically, the light intensity detection unit 17 outputs a detection signal (voltage) corresponding to the light intensity, and this detection signal is converted into a digital value by an A / D converter (not shown) to obtain light intensity information. It outputs to the laser output control part 100 mentioned later. Since the light intensity detector 17 only needs to be able to detect the light intensity of each of the laser beams R, G, and B, it is not the optical path of the combined laser beam C, for example, each of the laser beams R, G before being combined. , B may be provided separately at locations where the light intensity of each can be detected.

The scanning unit 20 receives the synthesized laser beam C from the laser output device 10 and scans the received synthesized laser beam C on the screen 30. As a result, the image M is displayed on the screen 30.

The screen 30 displays the image M on the front side by receiving and transmitting the synthetic laser beam C from the scanning unit 20 on the back side. The screen 30 is configured by, for example, a holographic diffuser, a microlens array, a diffusion plate, and the like.

The plane mirror 40 receives the display light L representing the image M displayed on the screen 30 and reflects it to the concave mirror 50 side.

The concave mirror 50 reflects the display light L from the plane mirror 40 in the direction of the windshield 3. The display light L reflected by the concave mirror 50 is emitted from the HUD device 1 and reaches the windshield 3.

The illuminance sensor 60 is an illuminance sensor that detects the illuminance outside the HUD device 1, detects the illuminance around the observer 4 (vehicle 2), and controls the light control unit 14 based on the illuminance data. Then, the brightness of the image M is adjusted by adjusting the light intensity of the synthetic laser beam C.

Next, an output adjustment method of the laser output device 10 will be described with reference to FIGS. FIG. 5 is a block diagram showing the electrical configuration of the adjustment device 200 and the laser output device 10 used in the output adjustment method of the laser output device 10, and FIG. 6 shows the steps of the output adjustment method of the laser output device 10. FIG. 7 is a flowchart illustrating an example of the relationship between the angle θ of the polarization direction conversion unit 13 and the light intensity of the laser light.

(Output Adjustment Method) First, when adjusting the output of the laser output device 10, the laser output control unit 100 is connected to the adjustment device 200. The adjustment device 200 is a device for adjusting the angle θ of the λ / 2 wavelength plate 13 to an appropriate position. When the angle adjustment of the λ / 2 wavelength plate 13 is completed, the adjustment device 200 is disconnected from the laser output control unit 100.

The adjustment device 200 includes an adjustment control unit 210 that controls the entire adjustment device 200, a light source adjustment unit 220 that drives the light source 11 of the laser output device 10, and a polarization control element that drives the polarization control element 142 of the laser output device 10. An adjustment unit 230, a light intensity information acquisition unit 240 that acquires light intensity information from the light intensity detection unit 17, and an angle adjustment unit 250 that adjusts the angle θ of the λ / 2 wavelength plate 13 are provided.

As step S11 of the output adjustment method, the light source 11 and the light control unit 14 are assembled together. At this time, the polarization directions of the laser beams R, G, and B and the transmission axes of the incident side polarizing plate 141 and the outgoing side polarizing plate 143 are assembled so as to have a specific relationship. Specifically, as described above, the transmission axis of the exit-side polarizing plate 143 is disposed so as to be orthogonal to the polarization directions of the laser beams R, G, and B, and the transmission axis of the incident-side polarizing plate 141 is the exit side. The polarizing plate 143 is disposed so as to be orthogonal to the transmission axis. The light sources 11a, 11b, and 11c that emit laser beams of different colors are respectively fixed with an adhesive or the like while adjusting the polarization direction and the optical axis.

Next, in step S12, the direction of the index portion indicating the fast axis of the λ / 2 wavelength plate 13 is shifted from the ideal fast axis direction in a predetermined rotational direction. The ideal fast axis direction is a direction in which the fast axis is perpendicular to the transmission axis of the exit-side polarizing plate 143. In addition, specifically, the arrangement in a predetermined rotational direction means that the λ / 2 wavelength plate 1
The index portion indicating the phase advance axis of 3 is about −5 degrees counterclockwise (CCW: Counter Clock Wise) in the laser beam traveling direction with respect to the direction orthogonal to the transmission axis of the output-side polarizing plate 143. It is to rotate and arrange. In this way, by arranging the indicator portion indicating the fast axis of the λ / 2 wavelength plate 13 by rotating it in a specific direction in advance, the λ / 2 wavelength plate 13 is placed in a certain direction in the light intensity detection step described later. By rotating, the fixed angle θ of the λ / 2 wavelength plate 13 can be quickly determined.

In step S13 (laser light output step), the adjustment control unit 210 drives the single color light source 11 of the light sources 11 with a constant output via the light source adjustment unit 220, and emits single color laser light. When the angle adjustment of the λ / 2 wavelength plate 13 arranged on the optical path of the light source 11 of one color is completed, the light sources 11 of other colors are driven.

In step S14 (polarization control step), the adjustment control unit 210 drives the polarization control element 142 off (applied voltage is 0 V) via the polarization control element adjustment unit 230. Then, the monochromatic laser light emitted from the light source 11 passes through the polarization control element 142 without changing the polarization direction, enters the output-side polarizing plate 143, and matches the transmission axis of the output-side polarizing plate 143. Part of the light passes through the exit side polarizing plate 143.

In step S <b> 15 (light intensity detection step), the laser light transmitted through the emission-side polarizing plate 143 reaches the light intensity detection unit 17, and the light intensity detection unit 17 provides the light intensity information to the light intensity information acquisition unit 240. Output. The adjustment control unit 210 stores the light intensity information input via the light intensity information acquisition unit 240 and the angle θ of the λ / 2 wavelength plate 13. The adjustment control unit 210 acquires a plurality of relationships between the light intensity information and the angle θ of the λ / 2 wavelength plate 13 while rotating the angle θ of the λ / 2 wavelength plate 13.

In step S16 (light intensity detection step), the adjustment control unit 210 determines whether the light intensity information with respect to the angle θ of the λ / 2 wavelength plate 13 has a minimum value, as shown in FIG.

When the light intensity information with respect to the angle θ of the λ / 2 wavelength plate 13 does not take the minimum value (NO in step S16), the process proceeds to step S17 (light intensity detection step), and the adjustment control unit 210 sets the angle adjustment unit 250. Then, the angle θ of the λ / 2 wavelength plate 13 is finely rotated, and light intensity information is input again in step S17 (light intensity detection step), and the process returns to step S16 to determine whether the light intensity information has taken a minimum value. .

On the other hand, when it is determined that the light intensity information with respect to the angle θ of the λ / 2 wavelength plate 13 has a minimum value (YES in step S16), the process proceeds to step S19 (polarization direction adjustment step), and the adjustment control unit 210 The λ / 2 wavelength plate 13 is rotated to an angle θ at which the light intensity information takes a minimum value via the adjustment unit 250, and the angle of the λ / 2 wavelength plate 13 is fixed. The λ / 2 wave plate 13 is fixed with an adhesive such as a UV curable resin, but the fixing method is not limited to this.

  As described above, according to the output adjustment method of the laser output device 10 in the present embodiment, the light source 11 that emits the laser light and the polarization direction of the laser light are converted onto the optical path of the laser light emitted from the light source 11. A λ / 2 wavelength plate 13 is disposed, a polarization control element 142 for controlling the polarization direction of the laser light is disposed on the optical path of the laser light emitted from the λ / 2 wavelength plate 13, and the laser emitted from the polarization control element 142 An emission-side polarizing plate 143 is disposed on the optical path of the light, the laser light is emitted from the light source 11, the polarization control element 142 is turned off (applied voltage is 0 V), and the angle θ of the λ / 2 wavelength plate 13 is adjusted. The light intensity of the laser light is detected, and the angle θ at which the light intensity takes a minimum value is determined as a fixed angle. With such a configuration, the polarization direction of the light source 11 is transmitted through the output side polarizing plate 143. Even when assembled off the axis, the polarization direction of the laser light can be incident on the polarization control element 142 in a state of being substantially perpendicular to the transmission axis of the output side polarizing plate 143, and the polarization control element 142 is turned off. At this time, it is difficult for laser light to be emitted from the emission-side polarizing plate 143, and when the polarization control element 142 is turned on, more laser light can be emitted from the emission-side polarizing plate 143 and adjusted by the light control unit 14. The dynamic range of the emitted laser light can be increased.

  In the laser output device 10 in the above-described embodiment, the emission-side polarizing plate 143 is disposed on the optical path of the synthetic laser beam C in which the optical axes of the laser beams R, G, and B are aligned. With such a configuration, the output side polarizing plate 143 can be made common, the number of steps for adjusting the transmission axis of the output side polarizing plate 143 can be reduced, and the member cost of the output side polarizing plate 143 can be reduced. be able to. In addition, since the polarization directions of the laser beams R, G, and B included in the synthetic laser beam C emitted from the laser output device 10 can be matched, the windshield 3 (transmission reflection surface) is directed to the observer 4. The reflectance of the laser beams R, G, and B included in the display light L at the windshield 3 is constant, and the observer 4 can visually recognize the virtual image V of the image M without losing the balance of the colors. Further, λ / 2 wavelength plates 13 (λ / 2 wavelength plates 13a, 13b, 13c) are provided on the optical paths of the laser beams R, G, B, respectively, and the respective angles θ of the λ / 2 wavelength plates 13 are adjusted. Thus, when assembling the light source 11 (the light sources 11a, 11b, and 11c), it is not necessary to completely match the respective polarization directions, and the number of assembling steps can be reduced.

[Modification] The present invention is not limited to the above embodiments and drawings. Changes (including deletion of constituent elements) can be added to the embodiments and the drawings as appropriate without departing from the scope of the present invention. Below, an example of a modification is described.

  In the above embodiment, the exit-side polarizing plate 143 is arranged on the optical path of the synthetic laser light C in which the optical axes of the laser lights R, G, and B are aligned, but on all the optical paths of the laser lights R, G, and B. You may provide the common output side polarizing plate 143 arrange | positioned over.

  Moreover, although the polarization control element 142 in the said embodiment arrange | positions the polarization control element 142 over the optical path of each laser beam R, G, B, and controls the pixel on each optical path, it is polarization control. The element 142 may be independently arranged on the optical path of each laser beam R, G, B.

  In the above embodiment, the λ / 2 wavelength plate 13 is fixed to the angle θ of the λ / 2 wavelength plate 13 where the light intensity information when the polarization control element 142 is turned off takes a minimum value. As shown, the λ / 2 wavelength plate 13 is fixed to the angle θ of the λ / 2 wavelength plate 13 where the light intensity information when the polarization control element 142 is turned on (the polarization direction is rotated approximately 90 degrees) takes a maximum value. Also good.

  Further, the angle θ for fixing the λ / 2 wavelength plate 13 is the angle θ of the λ / 2 wavelength plate 13 where the light intensity information when the polarization control element 142 is turned off is the minimum value, or the polarization control element 142 is turned on. The ratio between the light intensity information when the polarization control element 142 is turned on and the light intensity information when the polarization control element 142 is turned on is not the angle θ of the λ / 2 wavelength plate 13 at which the light intensity information takes a maximum value. You may fix to angle (theta) from which becomes the maximum. With such a configuration, the dynamic range of the emitted laser light can be reliably increased.

  Further, when the light intensity information when the polarization control element 142 is turned off is equal to or less than the threshold value stored in advance by the adjustment control unit 210, the angle θ at that time may be determined as a fixed angle. In addition, when the light intensity information when the polarization control element 142 is turned on is equal to or greater than a threshold value stored in advance by the adjustment control unit 210, the angle θ at that time may be determined as a fixed angle. Further, in the λ / 2 wavelength plate 13, the difference between the light intensity information when the polarization control element 142 is turned off and the light intensity information when the polarization control element 142 is turned on is equal to or greater than a threshold stored in the adjustment control unit 210 in advance. The angle θ may be fixed.

  In the laser output device 10 in the above embodiment, the polarization control element 142 and the emission-side polarizing plate 143 function as one normally black liquid crystal element, but function as a normally white liquid crystal element. You may comprise.

  The polarization control element 142 only needs to be able to control the polarization direction. That is, instead of the VA liquid crystal element in the above embodiment, the polarization control element 142 is composed of a λ / 2 wavelength plate and an actuator that rotates the λ / 2 wavelength plate, and rotates the λ / 2 wavelength plate. The light may be dimmed.

  Moreover, since the polarization direction conversion part 13 should just be able to control a polarization direction, you may comprise it with a liquid crystal element instead of the (lambda) / 2 wavelength plate in the said embodiment. In this case, instead of setting the angle θ of the λ / 2 wavelength plate 13 in the output adjustment method of the above embodiment, the drive value of the liquid crystal element is set.

1 HUD device (head-up display device) 2 vehicle 3 windshield 4 observer 10 laser output device 11 light source 12 condensing optical system 13 λ / 2 wavelength plate (polarization direction conversion unit) 14 dimming unit 15 optical axis adjustment unit 16 Transmitting / reflecting unit 17 Light intensity detecting unit 100 Laser output control unit 141 Incident side polarizing plate 142 Polarization control element 143 Outgoing side polarizing plate (polarizing plate) 200 Adjustment device 210 Adjustment control unit 220 Light source driving unit 230 Polarization control element driving unit 240 Light Intensity information acquisition unit 250 Angle adjustment unit B Blue laser beam C Synthetic laser beam D Reflected beam G Green laser beam L Display beam M Image R Red laser beam V Virtual image

Claims (8)

A light source that emits laser light;
A polarization direction converter that is located on the optical path of the laser beam emitted from the light source and converts the polarization direction of the laser beam;
A polarization control element that is positioned on the optical path of the laser light emitted from the polarization direction converter and controls the polarization direction of the laser light,
In a laser output device comprising a polarizing plate located on the optical path of the laser light emitted from the polarization control element,
The polarization direction conversion unit turns on or off the polarization direction in which the light intensity of laser light emitted from the laser output device takes an extreme value when the polarization control element is turned on or off, or the polarization control element. The polarization direction of the laser beam incident on the polarization direction in which the difference in the light intensity of the laser beam emitted from the laser output device takes a maximum value,
A laser output device characterized by that. The light source has a plurality of light sources that emit laser beams of different colors, and the polarization directions of the plurality of light sources are fixed and fixed when emitted from a laser output device,
The laser output device according to claim 1. The polarizing plate is disposed on an optical path of a synthetic laser beam in which optical axes of laser beams of different colors emitted from the plurality of light sources are aligned.
The laser output device according to claim 1, wherein the laser output device is a laser output device. The polarization direction conversion unit is disposed on an optical path of laser beams of different colors emitted from the plurality of light sources, and the polarization direction conversion unit individually determines the polarization direction of the incident laser light for each of the light sources. Convert,
The laser output device according to any one of claims 1 to 3, wherein The polarization direction conversion unit is composed of a λ / 2 wavelength plate, and converts the polarization direction of the emitted laser light by adjusting the installation angle.
The laser output device according to claim 1, wherein the laser output device is a laser output device. A light source that emits laser light;
A polarization direction converter that is located on the optical path of the laser beam emitted from the light source and converts the polarization direction of the laser beam;
A polarization control element that is positioned on the optical path of the laser light emitted from the polarization direction converter and controls the polarization direction of the laser light,
In a method for adjusting the output of a laser output device, comprising a polarizing plate positioned on the optical path of laser light emitted from the polarization control element,
A laser light output step for emitting laser light to the light source;
A polarization control step of turning on and / or off the polarization control element;
A light intensity detection step of detecting the light intensity of the laser light emitted from the polarizing plate while adjusting the angle of the polarization direction converter;
The polarization direction of the laser beam emitted from the polarization direction conversion unit, the polarization direction in which the light intensity detected in the light intensity detection step takes an extreme value, or the light intensity detection by turning on and off the polarization control element A polarization direction adjustment step of adjusting the polarization direction in which the difference in light intensity detected in the process takes a maximum value,
A method for adjusting the output of a laser output device. The light source has a plurality of light sources that emit laser beams of different colors,
The polarization direction conversion unit is disposed for each of the plurality of light sources, and the polarization direction of the laser light emitted from the polarization direction conversion unit is individually adjusted.
The method of adjusting an output of a laser output device according to claim 6. The light source has a plurality of light sources that emit laser beams of different colors,
Before the polarization direction adjustment step, comprising a light source fixing step of fixing the polarization directions of the plurality of light sources to be aligned.
The method of adjusting an output of a laser output device according to claim 6.

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