JP6792194B2 - Wavelength estimation device, light source device, image display device, object device, wavelength estimation method and light source control method - Google Patents

Description

The present invention relates to a wavelength estimation device, a light source device, an image display device, an object device, a wavelength estimation method, and a light source control method.

Conventionally, a wavelength measurement method for measuring the wavelength of light from a light source (for example, a superheterodyne method using an optical bandpass filter) is known.

Further, there are known devices that synthesize light from a plurality of light sources having different emission wavelength bands and display a virtual image (see, for example, Patent Documents 1 and 2).

For example, in order to display a high-quality virtual image in the devices disclosed in Patent Documents 1 and 2, it is necessary to measure or accurately estimate the wavelength of light from a light source.

However, if the conventional wavelength measurement method is introduced into the devices disclosed in Patent Documents 1 and 2, for example, there is a concern that the configuration becomes complicated.

The present invention is a wavelength estimation device that estimates the wavelength of light from a light source, the light detector that receives the light from the light source, the detection system that detects the ambient temperature around the light source, and the light detection. Based on the amount of light received by the device, the ambient temperature detected by the detection system, and the equation λ = λ (0) + α × (Ta-Ta (0)) + β × (PP (0)). It is a wavelength estimation device including the estimation means for estimating the wavelength. However, λ: current wavelength, λ (0): reference wavelength, α: temperature coefficient, Ta: current atmospheric temperature, Ta (0): atmospheric temperature at the time of reference wavelength measurement, β: light amount coefficient, P: current Emission light amount, P (0): Emission light amount at the time of reference wavelength measurement.

According to the present invention, the wavelength of light from a light source can be estimated with high accuracy by a simple configuration.

It is a figure which shows the schematic structure of the HUD apparatus of one Embodiment. It is a block diagram which shows the hardware composition of the control system of a HUD apparatus. It is a functional block diagram of the HUD apparatus. It is a figure for demonstrating the optical deflector of a HUD apparatus. It is a figure which shows an example of the scanning line locus at the time of two-dimensional scanning. It is a figure for demonstrating the light source apparatus of a HUD apparatus. It is a figure which shows the spectrum distribution of the high-power semiconductor laser which oscillates in the vertical multimode. It is a graph which shows the self-temperature dependence and the atmosphere temperature dependence of the wavelength of the light from a red semiconductor laser. It is a graph which shows the self-temperature dependence and the atmosphere temperature dependence of the wavelength of the light from a green semiconductor laser. It is a graph which shows the self-temperature dependence and the atmosphere temperature dependence of the wavelength of the light from a blue semiconductor laser. It is a figure for demonstrating how to obtain a reference wavelength. It is a flowchart for demonstrating the light source control process. It is a flowchart for demonstrating the emission light amount setting process. It is a figure for demonstrating an example (modification example 1) in which a light receiving element is arranged in a package in which a semiconductor laser is housed. It is a figure for demonstrating another example (modification example 2) in which a light receiving element is arranged in a package in which a semiconductor laser is housed. It is a figure for demonstrating the light source apparatus which has a single semiconductor laser. It is a figure for demonstrating the procedure for setting the emission light amount of each semiconductor laser.

Hereinafter, the HUD device 100 as the image display device of one embodiment will be described with reference to the drawings. In addition, "HUD" is an abbreviation for "head-up display".

FIG. 1 schematically shows the overall configuration of the HUD device 100 of the present embodiment.

<< Overall configuration of HUD device >>
By the way, the projection method of the head-up display is a "panel method" in which an intermediate image is formed by an imaging device such as a liquid crystal panel, a DMD panel (digital mirror device panel), and a vacuum fluorescent display (VFD), and is emitted from a laser light source. There is a "laser scanning method" in which an intermediate image is formed by scanning a laser beam with a two-dimensional scanning device. In particular, the latter laser scanning method, unlike the panel method in which an image is formed by partial shading of full-screen light emission, can assign light emission / non-light emission to each pixel, and thus generally forms a high-contrast image. be able to.

Therefore, the HUD device 100 employs a "laser scanning method". Of course, the above-mentioned "panel method" can also be used as the projection method.

As an example, the HUD device 100 is mounted on a moving body such as a vehicle, an aircraft, a ship, or a robot, and navigation information (see FIG. 1) necessary for maneuvering the moving body via the front windshield 50 (see FIG. 1) of the moving body (see FIG. 1). For example, the speed of the moving body, the direction of travel, the distance to the destination, the name of the current location, the presence / absence and position of an object in front of the moving body, signs such as the speed limit, information such as traffic jam information) can be visually recognized. In this case, the front windshield 50 also functions as a transmission / reflection member that transmits a part of the incident light and reflects at least a part of the remaining part. In the following, an example in which the HUD device is mounted on an automobile provided with the front windshield 50 will be mainly described.

As shown in FIG. 1, the HUD device 100 includes an optical scanning means 10 including a light source unit 11, an optical deflector 15, and a scanning mirror 20 (for example, a concave mirror), a screen 30, and a concave mirror 40, and includes a front window. By irradiating the shield 50 with light (image light) that forms an image, the virtual image I can be visually recognized from the viewpoint position of the viewer A (here, the driver who is a occupant of the automobile). That is, the viewer A can visually recognize the image (intermediate image) formed (drawn) on the screen by the optical scanning means 10 as a virtual image I through the front windshield 50.

The HUD device 100 is arranged below the dashboard of the automobile as an example, and the distance from the viewpoint position of the viewer A to the front windshield 50 is about several tens of cm to at most 1 m.

Here, the concave mirror 40 is designed by using existing optical design simulation software so as to have a constant focusing power so that the imaging position of the virtual image I becomes a desired position.

In the HUD device 100, the focusing power of the concave mirror 40 is set so that the virtual image I is displayed at a position (depth position) of 1 m or more and 10 m or less (preferably 6 m or less) from the viewpoint position of the viewer A. There is.

Normally, the front windshield is not flat but slightly curved. Therefore, the image formation position of the virtual image I is determined by the curved surfaces of the concave mirror 40 and the front windshield 50.

The light source unit 11 synthesizes laser beams of three colors of R, G, and B modulated according to the image data. A part of the combined light in which the three colors of laser light are combined is guided to the reflecting surface of the light deflector 15. The optical deflector 15 is a MEMS scanner manufactured by a semiconductor manufacturing process or the like, and includes a single micromirror that can swing independently around two orthogonal axes. The optical deflector 15 may be a combination of two MEMS scanners including a minute mirror that can swing around one axis. Further, the scanner is not limited to the MEMS scanner, and for example, a galvano scanner or a polygon scanner may be used. Details of the light source unit 11 and the light deflector 15 will be described later.

The light corresponding to the image data from the light source unit 11 (a part of the synthetic light) is deflected by the light deflector 15, folded back while being suppressed by the scanning mirror 20, and irradiated to the screen 30. Therefore, the screen 30 is light-scanned to form an intermediate image on the screen 30. The concave mirror 40 is preferably designed and arranged so as to correct an optical distortion element in which the horizontal line of the intermediate image becomes convex upward or downward due to the influence of the front windshield 50.

The light passing through the screen 30 is reflected by the concave mirror 40 toward the front windshield 50. A part of the luminous flux incident on the front windshield 50 is transmitted through the front windshield 50, and at least a part of the remaining light is reflected toward the viewpoint position (eye point) of the viewer A. As a result, the viewer A can see the magnified virtual image I of the intermediate image through the front windshield 50. That is, the virtual image I is enlarged and displayed through the front windshield 50 when viewed from the viewer.

Even if a combiner is arranged as a transmission reflection member on the viewpoint position side of the viewer A with respect to the front windshield 50 and the combiner is irradiated with the light from the concave mirror 40, the case where only the front windshield 50 is used is used. Similarly, a virtual image can be displayed.

<< Hardware configuration of the control system of the HUD device >>
FIG. 2 shows a block diagram showing the hardware configuration of the control system of the HUD device 100. As shown in FIG. 2, the control system of the HUD device 100 includes an FPGA 600, a CPU 602, a ROM 604, a RAM 606, an I / F 608, a bus line 610, an LD driver 6111, and a MEMS controller 615.

The FPGA 600 is an LD control circuit that controls the LD described later via the LD driver 6111 based on the image data, the output of the photodetector 117 or the signal processing unit 120 described later, and the output of the scanning light detection unit 60. Includes an optical deflector control circuit that controls the optical deflector 15 via the 700 and the MEMS controller 615. The CPU 602 controls each function of the HUD device 100. The ROM 604 stores an image processing program executed by the CPU 602 to control each function of the HUD device. The RAM 606 is used as a work area for the CPU 602. The I / F 608 is an interface for communicating with an external controller or the like, and is connected to, for example, a CAN (Controller Area Network) of an automobile.

<< Functional block of HUD device >>
FIG. 3 shows a block diagram showing the functions of the HUD device 100. As shown in FIG. 3, the HUD device 100 includes a vehicle information input unit 800, an external information input unit 802, an image data generation unit 804, and an image drawing unit 806. Vehicle information (information such as speed, mileage, distance to an object, brightness of the outside world, etc.) is input to the vehicle information input unit 800 from CAN or the like. Information outside the vehicle (navigation information from GPS, etc.) is input to the external information input unit 802 from the external network. The image data generation unit 804 generates image data of an image to be drawn based on the information input from the vehicle information input unit 800 and the external information input unit 802, and sends the image data to the FPGA 600. The image drawing unit 806 includes a control unit 8060, and the control unit 8060 transmits a control signal for starting or ending image drawing to the FPGA 600.

<< Configuration of optical deflector >>
FIG. 4 shows the configuration of the light deflector 15. The optical deflector 15 is a MEMS scanner manufactured by a semiconductor process, and as shown in FIG. 4, includes a mirror 150 having a reflecting surface and a plurality of beams arranged in the X-axis direction, and two adjacent beams. Has a pair of meandering portions 152 connected so as to meander through the folded portions. The two adjacent beams of each meandering portion 152 are beam A (152a) and beam B (152b), and are supported by the frame member 154. A plurality of piezoelectric members 156 (for example, PZT) are individually provided on the plurality of beams. By applying different voltages to the piezoelectric members of the two adjacent beams of each meandering portion, the two adjacent beams of the meandering portion bend in different directions, which are accumulated, and the mirror 150 is rotated around the X axis (=). It will rotate at a large angle in the vertical direction). With such a configuration, optical scanning in the vertical direction centered on the X-axis becomes possible at a low voltage. On the other hand, in the horizontal direction centered on the Y-axis, optical scanning by resonance is performed using a torsion bar or the like connected to the mirror 150.

The light deflector 15 configured as described above scans the laser beam two-dimensionally (for example, raster scan) with respect to the image drawing area of the screen 30 (see FIG. 5), and at the scanning position of the laser beam. By controlling the light emission of the LD accordingly, it is possible to draw each pixel and display a virtual image. In FIG. 5, Ps is the scanning line pitch.

《Optical scanning, virtual image display》
From the HUD device 100, only a point image corresponding to the diameter of the laser beam is instantaneously projected, but since scanning is performed at a very high speed, a sufficient afterimage remains in the human eye in one frame image. By utilizing this afterimage phenomenon, the driver perceives that the image is projected on the "display area". In reality, the image reflected on the screen 30 is reflected by the concave mirror 40 and the front windshield 50 and perceived by the driver as a virtual image in the "display area". Since it is such a mechanism, if the image is not displayed, the light emission of the LD may be stopped. That is, it is possible to set the brightness of the portion other than the portion where the virtual image is displayed in the "display area" to substantially zero.

That is, the imaging position of the virtual image by the HUD device 100 is an arbitrary position within a predetermined "display area" where the virtual image can be imaged. This "display area" is determined by the specifications at the time of designing the HUD device.

In this way, by adopting the "laser scanning method", it is possible to take measures such as turning off the LD or reducing the amount of light because there is no need to display the portion other than the portion to be displayed.

On the other hand, in the "panel method" in which an intermediate image is expressed by an imaging device such as a liquid crystal panel and a DMD panel, it is necessary to illuminate the entire panel, so that the image signal is displayed in black in order to hide it. Even if it is, the black part may appear to be raised because it is difficult to completely set it to 0 due to the characteristics of the liquid crystal panel or the DMD panel, but the laser scanning method makes it possible to eliminate the black part.

Here, as shown in FIG. 5, the scanning light detection unit 60 is provided in the peripheral region of the image drawing region (also referred to as “effective scanning region”) on the screen 30. The scanning light detection unit 60 is provided to detect the operation of the photodetector 15, and detects the scanning timing (scanning position of the beam) by irradiating the signal region with light, and the light accompanying the environment and changes over time. It is used to control changes in the characteristics of the deflector 15 to maintain a constant image quality. The scanning light detection unit 60 includes, for example, a photodiode, a phototransistor, and the like. The output signal of the scanning light detection unit 60 is sent to the FPGA 600.

《Light source part》
The light source unit 11 will be described in detail below. FIG. 6 schematically shows the configuration of the light source unit 11. In the following, the αβγ three-dimensional Cartesian coordinate system shown in FIG. 6 and the like will be described as appropriate.

As shown in FIG. 6 as an example, the light source unit 11 includes a plurality of (for example, three) light sources including a light emitting element having one or a plurality of light emitting points and a package accommodating the light emitting elements. The light emitting elements of the three light sources are referred to as light emitting elements 111R, 111B, and 111G, respectively.

Further, in addition to the above three light sources, the light source unit 11 combines a plurality of (for example, three) coupling lenses 112R, 112G, 112B, and a plurality of (for example, three) aperture members 113R, 113G, 113B, two optical paths. It includes elements 114 and 115, a reflection mirror 118, a condenser lens 116, an optical detector 117, and the like. Each component of the light source unit 11 is assembled to the housing 11a.

Each light emitting element is an end face light emitting type semiconductor laser (LD: laser diode) having different oscillation wavelength bands (emission wavelength bands). Assuming that the oscillation wavelengths (design values) of the light emitting elements 111R, 111G, and 111B are λR, λG, and λB, for example, λR = 653 nm, λG = 515 nm, and λB = 453 nm. Here, the emission directions of the light emitting elements 111R, 111G, and 111B are all in the + α direction. Each light emitting element is mounted on a circuit board 200 provided with an LD driver 6111. Hereinafter, each light emitting element is also referred to as a "semiconductor laser" or "LD".

The luminous fluxes Lr, Lg, and Lb emitted from the LD111R, 111G, and 111B are coupled to the subsequent optical system by the corresponding coupling lenses 112R, 112G, 112B.

The coupled light flux is shaped by the corresponding aperture members 113R, 113G, 113B. The opening shape of each aperture member can be various shapes such as a circle, an ellipse, a rectangle, and a square depending on the divergence angle of the light flux.

The luminous flux Lb via the aperture member 113B is reflected by the reflection mirror 118 in the −β direction and is incident on the optical path synthesis element 114 (for example, a dichroic mirror).

The luminous flux Lg via the aperture member 113G is optical path-combined with the luminous flux Lb by the optical path synthesizing element 114 (for example, a dichroic mirror). More specifically, the luminous flux Lb via the reflection mirror 118 is transmitted in the −β direction through the center of the optical path synthesizer 114, and the luminous flux Lg via the aperture member 113G is reflected in the −β direction at the center of the optical path synthesizer 114. ..

Then, the combined luminous flux Lgb in which the luminous flux Lg and the luminous flux Lb are combined and the luminous flux Lr via the aperture member 113R are combined by the optical path synthesizing element 115, and the combined luminous flux is branched into a transmitted luminous flux and a reflected luminous flux. Although the two optical path synthesis elements 114 and 115 and the reflection mirror 118 are separate bodies here, at least two of them may be provided integrally.

More specifically, a part of the combined luminous flux Lgb is transmitted in the −β direction through the center of the optical path synthesis element 115, and the rest is reflected in the + α direction at the center of the optical path synthesis element 115. A part of the luminous flux Lr via the aperture member 113R is reflected in the −β direction at the center of the optical path synthesis element 115, and the rest is transmitted through the center of the optical path synthesis element 115 in the + α direction.

That is, from the optical path synthesizing element 115, the combined luminous flux Lrgb1 in which a part of the combined luminous flux Lgb and a part of the luminous flux Lr are combined is emitted in the −β direction, and the balance of the combined luminous flux Lgb and the remaining portion of the luminous flux Lr are combined. The luminous flux Lrgb2 is emitted in the + α direction.

The combined luminous flux Lrgb1 is applied to the light deflector 15 via a light transmitting window member 5 attached to the periphery of the opening of the housing 11a so as to cover the opening, and an image is drawn (virtual image display) on the screen 30. Used for. A meniscus lens having a concave surface facing the optical deflector 15 may be installed between the optical path synthesizer 115 and the optical deflector 15.

The combined luminous flux Lrgb2 is guided to the photodetector 117 via the condenser lens 116. The photodetector 117 outputs a signal corresponding to the amount of light of the received combined luminous flux Lrgb2 to the LD control circuit 700. The photodetector 117 includes a light receiving element 117a and a current-voltage converter 117b that converts the output current of the light receiving element 117a into a voltage signal (light receiving signal). As the light receiving element 117a, for example, a photodiode (PD) or a phototransistor can be used.

A signal processing unit 120 that time-averages the received signal is provided in the subsequent stage of the current-voltage converter 117b. The signal processing unit 120 integrates the received light signals input in a certain time zone T, averages the integrated values over time (divides by T), and outputs the integrated values to the LD control circuit 700. The signal processing unit 120 is not essential, and the received signal from the current-voltage converter 117b may be directly output to the LD control circuit 700.

As is clear from FIG. 6, the optical path lengths from each light emitting element to the optical path synthesis element 115 are different from each other. Specifically, the optical path length from the light emitting element 111B to the optical path synthesis element 115 is the longest, and the optical path length from the light emitting element 111R to the optical path synthesis element 115 is the shortest. This is because when white is composed of a virtual image, the RGB composition ratio is about 2.5: 1: 0.5, a large amount of red light is required, and conversely, the amount of blue light may be small. This is to suppress a decrease in light utilization efficiency due to the light emitting element.

The LD control circuit 700 generates a modulation signal (pulse signal) for each light emitting element based on the output signal of the photodetector 117, and sends it to the LD driver 6111. The LD driver 6111 applies a drive current corresponding to the modulation signal of each light emitting element to the light emitting element.

By the way, in order to display a virtual image of a desired color in the HUD device, it is necessary for the light source unit 11 to generate light of a desired color.

That is, it is necessary that the power balance of the light (emitted light) emitted from the three semiconductor lasers 111R, 111G, 111B having the oscillation wavelengths λR, λG, and λB and synthesized is appropriate.

Therefore, the ratio of the amount of emitted light (ratio of the driving current) of the light emitting elements 111R, 111G, and 111B is set to a ratio a: b: c according to the oscillation wavelengths λR, λG, and λB for producing light of a desired color. Once set, in theory, it should be able to produce the desired color of light.

However, in reality, the oscillation wavelength of the semiconductor laser fluctuates depending on the ambient ambient temperature and the amount of emitted light that increases or decreases depending on the amount of current (driving current) injected into the semiconductor laser, so that light of a desired color is generated. There is concern that it will not be possible. In particular, in the HUD device, since the dynamic range of light and darkness of the surrounding environment of the vehicle is large, the fluctuation of the amount of emitted light required to cope with it becomes large, and the atmospheric temperature fluctuates depending on the time and the position of the vehicle, which in turn oscillates. The wavelength fluctuates. That is, the oscillation wavelength deviates from the design value. If the oscillation wavelength deviates, the oscillation wavelength band including the oscillation wavelength also deviates.

Therefore, in order to display a virtual image of a desired color in the HUD device, the wavelength of the emitted light of each semiconductor laser is monitored in a timely manner, and the amount of emitted light of the semiconductor laser is appropriately controlled based on the monitored wavelength. There is a need.

As a method for measuring wavelength, a superheterodyne method using an optical bandpass filter is known, but when this is introduced, the HUD device becomes large and miniaturization is required due to the limitation of the installation space in the vehicle. This is not preferable due to the nature of the HUD device.

Therefore, the inventors have focused on the fact that the temperature dependence of the oscillation wavelength is linear regardless of the type of the semiconductor laser, and by utilizing this property, the wavelength of the emitted light of the semiconductor laser can be estimated accurately. I found.

Here, the wavelength estimated by the wavelength estimation unit 700a (wavelength to be estimated) will be described. FIG. 7 shows the spectrum distribution of a high-power semiconductor laser oscillating in vertical multimode.

As can be seen from FIG. 7, in a semiconductor laser having such a spectrum distribution in the oscillation wavelength band, unlike a semiconductor laser that oscillates in a vertical single mode, the wavelength of the emitted light of this semiconductor laser ( It is very difficult to determine the wavelength to be estimated.

However, when considering the generation of virtual image colors in a HUD device, if the wavelength to be estimated is defined as the wavelength obtained by weighted averaging the wavelength components having an intensity of -20 dB or more of the peak intensity in the vertical multimode, this wavelength is defined. The inventors have found that the correlation between power balance and color generation based on is very high.

Wavelength components with an intensity smaller than -20 dB can be almost ignored as an error in color generation, and if it is a weighted average wavelength, the color coordinates of a semiconductor laser like the dominant wavelength used in LEDs and the like. It is easy to measure because it is not necessary to obtain.

On the other hand, in a semiconductor laser that oscillates in a vertical single mode, the wavelength of a single spectrum itself is the wavelength to be estimated.

The "temperature dependence of the oscillation wavelength" ("the temperature dependence of the emitted light of the semiconductor laser") will be specifically described below.

8 to 10 show the temperature of the package in which the semiconductor laser is housed and the measured value of the oscillation wavelength for the semiconductor laser having the design value of the oscillation wavelength of 653 nm (red), 515 nm (green), and 453 nm (blue). The relationship is shown.

From FIGS. 8 to 10, the temperature dependence of the oscillation wavelength does not depend on the type of semiconductor laser.
It can be understood that there are two types of temperature dependence: (1) atmospheric temperature dependence due to the temperature of the surrounding atmosphere (2) self-temperature dependence due to self-heating according to the amount of emitted light.

In order to accurately estimate the wavelength of the emitted light of the semiconductor laser, it is necessary to take these two types of temperature dependence into consideration.

Therefore, in the present embodiment, as will be described in detail below, for example, the temperature sensor 130 (see FIG. 6) is used to monitor the ambient temperature around the semiconductor laser, and the photodetector 117 is used to monitor the temperature of the semiconductor laser. By monitoring the amount of emitted light, the wavelength of the emitted light of each semiconductor laser is estimated from both the "atmosphere temperature dependence" and the "self-temperature dependence".

Returning to FIG. 6, the LD control circuit 700 includes a wavelength estimation unit 700a, a power balance determination unit 700b, and a modulation signal generation unit 700c.

The wavelength estimation unit 700a estimates the wavelength of the emitted light of each semiconductor laser based on the output signal of the photodetector 117 and the output of the temperature sensor 130 or a detection means described later. Therefore, a wavelength estimation device is configured including a wavelength estimation unit 700a, a photodetector 117, and a temperature sensor 130 or a detection means.

Specifically, the wavelength estimation unit 700a _monitors the light reception light amount P _moni (output signal of the photodetector 117) in the light receiving element 117a, and the light utilization efficiency η from the semiconductor laser to the light receiving element 117a with _respect to the P _{moni. Is} calculated and converted into the amount of emitted light P of the current semiconductor laser (P = P _moni ÷ η).

As the oscillation method of the semiconductor laser, various pulse oscillations can be considered depending on what kind of information is generated as a virtual image of the HUD device. If the emitted light amount P is defined as "time averaged time average light amount", the wavelength The inventors have found that the estimation can be performed accurately.

Here, since the wavelength of the emitted light of the semiconductor laser depends on the ambient temperature as described above, it is preferable to install the temperature sensor 130 at a position where the ambient temperature of the semiconductor laser can be acquired.

Instead of detecting the ambient temperature with the temperature sensor 130, the package temperature T _pk , which is the temperature of the package containing the semiconductor laser, can be monitored by the temperature sensor (hereinafter referred to as "package temperature sensor"). good. As the package temperature sensor, either a contact type or a non-contact type may be used. Package temperature _{T pk,} ambient temperature _{T a,} the temperature _{T LD} of the semiconductor _{laser, T pk} = T a ₊ T _LD is established, be determined ambient temperature _{T a} from the temperature _{T LD} of the package temperature _{T pk} a semiconductor laser it can.

Here, the temperature _TLD of the semiconductor laser depends on the ratio of the on-time to the period of pulse oscillation, that is, the duty ratio.
Therefore, advance write the temperature T _LD of the semiconductor laser in accordance with the pre-Duty ratio of the respective colors of the semiconductor laser in the firmware of the wavelength estimator 700a, a pulse oscillation information (the semiconductor laser of each color when the acquired package temperature T _pk and from Duty ratio) reads the temperature _{T LD} of the semiconductor laser from the _firmware, by calculating the T pk _{-T LD,} it may be obtained the ambient temperature _{T a.} In this case, not all of the semiconductor laser for _T pk _{-T LD} not necessary to obtain the calculated _{T a} a may be determined to _{T a} to calculate the _T pk _{-T LD} for at least one semiconductor laser. However, since sometimes an error occurs in the _T pk _{-T LD} between the semiconductor laser, it obtains a plurality of semiconductor lasers to calculate the _T pk _{-T LD T a,} adopting the average or median of _{T a} Is preferable.

Moreover, it not lit the semiconductor laser (Duty ratio = 0%), the lowest temperature _{T LD} of the semiconductor laser, the temperature _{T LD} of the semiconductor laser is highest when the continuous lighting (Duty ratio = 100%) Therefore, the temperature change of the semiconductor laser with respect to the change of the duty ratio during that period can be assumed to be linear.
Therefore, the semiconductor laser of each color, and the temperature T _LD of the semiconductor laser in a state where no light the semiconductor laser in advance written the temperature T _LD of the semiconductor laser at the time of continuous lighting in the firmware of the wavelength estimator 700a, the temperature T _LD of the semiconductor laser when the acquired package temperature T _pk may be determined by calculation based on the Duty ratio. In this case, for the same reason as described above, it may be obtained the T _LD for at least one semiconductor laser.

Further, since the temperature T _LD of the semiconductor laser in the state where the semiconductor laser is not lit (Duty ratio = 0%) is generally 0 ° C., only the temperature _TL of the semiconductor laser when continuously lit is the wavelength. leave written to the firmware of the estimating section 700a, the semiconductor laser of the temperature T _LD of the semiconductor laser when the acquired package temperature T _pk when determined by calculation based on the Duty ratio is a state in which no light the semiconductor laser The temperature of T _LD = 0 ° C. may be calculated. In this case, for the same reason as described above, it may be obtained the T _LD for at least one semiconductor laser.

Or detection of ambient temperature _{T a} by monitoring the package temperature _{T pk} as described includes a package temperature sensor, and Duty ratio acquisition unit for acquiring Duty ratio of the semiconductor laser, and the _firmware, T pk _{-T LD} It is performed by a detection means including a calculation unit for calculating.

In order to speed up the pulse oscillation of the semiconductor laser, it is preferable that the wiring length between the LD driver 6111 and the semiconductor laser is short. In this case, the heat generated by driving the LD driver 6111 causes the ground layer of the circuit board 200 to be generated. It may propagate and promote the temperature rise of the semiconductor laser. In this case, the package temperature _{T pk} which the semiconductor laser is accommodated, the atmospheric temperature _{T a,} the temperature _T LD of the semiconductor laser, the temperature of the temperature _T 3 one temperature components of the _IC of the LD driver 6111 has been synthesized. That is, T _pk = T _a + T _LD + T _IC is established.
Further, when the LD driver 6111 is common to the semiconductor lasers of each color, it is necessary to consider the influence other than the duty ratio, for example, when only red is lit and other colors are not lit. .. Thus, in the method of extracting the ambient temperature T _a from the package temperature T _pk which the semiconductor laser is accommodated and should be considered for the effect of temperature T _IC of LD driver 6111.

In the present embodiment, as an example, the temperature sensor 130 is installed in the vicinity of the aperture member 113B in the housing 11a at a certain distance from each semiconductor laser. Of course, it may be provided at other positions such as near other aperture members, near the reflection mirror, near the optical path synthesizer, near the condensing lens, etc., but in any case, it is suitable for detecting the ambient temperature around the semiconductor laser. It is desirable to install it within a reasonable distance range.

The temperature sensor 130 may be any temperature sensor that can detect the temperature of the atmosphere around the light emitting element, and examples thereof include a thermocouple, a thermistor, a resistance temperature detector, and a radiation thermometer.

In addition to monitoring the amount of light received by the light receiving element 117a, the wavelength estimation unit 700a monitors the ambient temperature detected by the temperature sensor 130 or the detection means, and estimates the current wavelength of the emitted light of the semiconductor laser.

At this time, the current wavelength λ of the emitted light of the semiconductor laser is
λ ⁽⁰⁾ : Reference wavelength α: Atmospheric temperature coefficient T _a : Current atmospheric temperature _Ta ⁽⁰⁾ : Atmospheric temperature at the time of reference wavelength measurement β: Light intensity coefficient P: Current emission light intensity P ⁽⁰⁾ : Reference wavelength measurement The amount of emitted light at an hour is expressed by the following equation (1).
λ = λ ⁽⁰⁾ + α × (T _a −T _a ⁽⁰⁾ ) + β × (PP ⁽⁰⁾ )… (1)

The temperature coefficient α is the slope of the atmosphere temperature dependence graph in FIGS. 8 to 10, and the light amount coefficient β is the slope of the self-temperature dependence graph in FIGS. 8 to 10.

The reference wavelength λ ⁽⁰⁾ is preferably a weighted average wavelength. In this case, the current wavelength λ is also a weighted average wavelength.

By using the above equation (1), the current wavelength λ can be estimated accurately regardless of the current atmospheric temperature and the current amount of emitted light.

The reference wavelength λ ⁽⁰⁾ is “a certain condition” at an arbitrary atmospheric temperature _Ta ⁽⁰⁾ and an arbitrary light intensity P ⁽⁰⁾ if the pulse condition oscillated from the light emitting element is always fixed. However, the information generated as a virtual image of the HUD device 100 is various, and it is necessary to change the brightness of the virtual image of the HUD device 100 according to the brightness outside the vehicle. It is generally unlikely that it is fixed under one condition.

In this case, the reference wavelength λ ⁽⁰⁾ is preferably defined as a virtual wavelength at P ⁽⁰⁾ = 0 [W]. This is because there is no situation common to all pulse conditions other than P ⁽⁰⁾ = 0 [W].

Naturally, the wavelength cannot be actually measured under the condition of P ⁽⁰⁾ = 0 [W], but as shown in FIG. 11, P ₁ , P ₂ , ..., P ₅ , P ₆ and the amount of emitted light of the semiconductor laser are emitted. The virtual wavelength at P ⁽⁰⁾ = 0 [W] can be obtained by linearly interpolating from the corresponding wavelengths λ ₁ , λ ₂ , ..., λ ₅ and λ _{6 by} changing. The wavelength is λ ⁽⁰⁾ . At this time, since the ambient temperature can be regarded as substantially constant for an extremely short time, the measurement error of the reference wavelength hardly occurs.

In FIG. 11, the emission light amount of the semiconductor laser is changed in 6 steps and the wavelength is measured in each step. However, the wavelength is not limited to this, and the point is that the emission light amount of the semiconductor laser is changed in at least 2 steps. The wavelength may be measured at each stage. Since most LDs have very good linearity, for example, the intersection (intercept) between the straight line and the vertical axis passing through the two plots obtained by measuring the wavelength in two steps (low emission light amount and high emission light amount) is used as a reference. You can also find the wavelength.

Further, even among semiconductor lasers having the same oscillation wavelength band (same color), there are individual differences in the oscillation wavelength in the range of about ± 5 nm, so it is preferable to measure the reference wavelength for each semiconductor laser.

On the other hand, the temperature coefficient α and the light intensity coefficient β are determined to be constant values for each color because there is almost no individual difference for each semiconductor laser. Of course, in order to improve the wavelength estimation accuracy, the temperature coefficient α and the light amount coefficient β may be measured in advance for each individual, and the measured values may be written in the firmware of the wavelength estimation unit 700a.

The process of obtaining the reference wavelength shown in FIG. 11 is performed for each semiconductor laser using a wavelength measuring device (spectrum analyzer or the like). The acquired reference wavelength, the atmospheric temperature at the time of measuring the reference wavelength, and the amount of emitted light at the time of measuring the reference wavelength are substituted into the above equation (1). Specifically, the acquired reference wavelength, the atmospheric temperature at the time of measuring the reference wavelength, and the numerical values of the amount of emitted light are written in the firmware of the wavelength estimation unit 700a.

The wavelength estimation unit 700a receives light _amounts of light emitted from the semiconductor lasers 111R, 111G, and 111B at different timings and received by the light receiving element 117a at different timings P _moni ^(red) , P _moni ^(green) , and P _moni ^(blue). And calculate the amount of light emitted by the current light emitting element P ^(red) , P ^(green) , P ^(blue) from the monitor information (P ^(red) = P _moni ^(red) ÷ η ^(red) , P ^(Green) = P _moni ^(green) ÷ η ^(green) , P ^(blue) = P _moni ^(blue) ÷ η ^(blue) ).

The calculated wavelength estimator 700a from the information of the current ambient temperature T _a of the temperature sensor 130 or the detection means, a current wavelength λ of light being emitted from the semiconductor laser, the above (1) Then, the calculation result is sent to the power balance determination unit 700b.

The power balance determination unit 700b is based on the color of each pixel of the image data and the current wavelengths of the three semiconductor lasers, and each semiconductor has a suitable (appropriate) power balance for generating light of the color. The amount of emitted light of the laser is set, and the set value is sent to the modulation signal generation unit 700c.

Specifically, for example, in the chromaticity coordinates shown in FIG. 17, when the current wavelengths of the three semiconductor lasers 111R, 111G, and 111B are set to 650 nm, 515 nm, and 445 nm, respectively, two of the three semiconductor lasers 111R, 111G, and 111B are used. The amount of light emitted by one semiconductor laser is appropriately determined to generate a color P, and the amount of light emitted by the remaining one semiconductor laser is set to an appropriate value according to the color P so as to be a desired color (target color). In FIG. 17, all colors in a triangle having three points of 650 nm, 515 nm, and 445 nm as vertices can be generated. The horseshoe-shaped edge of FIG. 17 is called the "spectral locus" and is a line in which wavelength and color correspond.

The modulation signal generation unit 700c generates a modulation signal for each light emitting element based on the amount of light emitted from each light emitting element and image data set by the power balance determination unit 700b, and uses the output signal from the scanning light detection unit 60 as an output signal. Output to the LD driver 6111 at a predetermined timing based on the above.

As a result, the power balance of the emitted light is optimized from the three light emitting elements to generate a composite light of a desired color, and the image drawing area is scanned by the composite light to display a virtual image of the desired color.

That is, it is possible to display a high-quality color virtual image that faithfully reproduces the color information of each pixel of the image data.

The color of the virtual image has been described above. Regarding the brightness of the virtual image, by uniformly increasing or decreasing the amount of emitted light while keeping the ratio of the amount of emitted light after setting of the three light emitting elements 111R, 111G, and 111B constant. It is possible to control the virtual image to a desired color and a desired brightness.

The light source control process of this embodiment will be described below with reference to FIG. The flowchart of FIG. 12 is based on a processing algorithm executed by the LD control circuit 700. This light source control process is started, for example, when the electric system of the automobile on which the HUD device 100 is mounted is turned on and the HUD device 100 is activated. When the HUD device 100 is activated, the optical deflector 15 starts operating.

In the first step S1, each light emitting element is turned on. Specifically, the modulation signal generation unit 700c generates a modulation signal for each light emitting element according to the color of each pixel of the image data, and outputs the modulation signal to the LD driver 6111 at a predetermined timing based on the output signal of the scanning light detection unit 60. To do. As a result, a drive current corresponding to the modulation signal of each light emitting element is applied to the light emitting element, and the drawing of the image according to the image data on the screen 30 and the display of the virtual image are started.

In the next step S2, it is determined whether or not the scan has been performed a predetermined number of times. Specifically, the number of reciprocating or one-way scanning in the main scanning direction is counted based on the output signal of the scanning light detection unit 60 and the horizontal scanning frequency of the optical deflector 15, and when the number of counts reaches a predetermined number. , The process proceeds to the next step S3. That is, it is in a waiting state until the number of scans reaches a predetermined number. The "predetermined number of times" may be one to at least one frame of reciprocating scanning when counting in units of reciprocating scanning, and one to at least one frame when counting in one-way scanning units. The number of one-way scans is sufficient.

In step S3, the "emission light amount setting process" is performed. The details of the emission light amount setting process will be described later.

In the next step S4, each light emitting element is lit with the amount of light emitted after setting. Specifically, each light emitting element is turned on with the amount of light emitted set in step S3. As a result, the power balance of the emitted light of the three light emitting elements becomes appropriate, and a virtual image of a desired color is displayed.

In the next step S5, it is determined whether or not the processing is completed. When the electric system of the automobile on which the HUD device 100 is mounted is ON, the determination here is denied and the process returns to step S2, and when it is OFF, the determination here is affirmed and the flow ends.

In step S2 of the light source control process, it is determined whether or not the scanning has been performed a predetermined number of times. Instead, it may be determined whether or not a predetermined time has elapsed.

Hereinafter, the “emission light amount setting process” in step S3 of the light source control process will be described with reference to FIG. The flowchart of FIG. 13 is based on a processing algorithm executed by the LD control circuit 700. This emission light amount setting process is continuous when the scanning light is not applied to the effective scanning area (image drawing area) (time period when the image is not drawn), for example, when the scanning light is applied to the peripheral area of the effective scanning area. It is carried out at the transition time between frames.

In the first step S12, the time average light amount for each light emitting element is acquired. Specifically, each light emitting element is turned on in sequence, and a signal from the signal processing unit 120 in which the received signal for each lighting is time-averaged is acquired.

In the next step S13, the ambient temperature detected by the temperature sensor 130 is acquired.

In the next step S14, the wavelength λ of the emitted light of each light emitting element is estimated based on the acquired time average light amount (current emitted light amount) and atmospheric temperature (current atmospheric temperature). Specifically, the wavelength λ is estimated using the above equation (1).

In the next step S15, the amount of emitted light of each light emitting element is set based on the estimated wavelength λ (see FIG. 17).

In the above embodiment, the light receiving element is provided outside the package accommodating the semiconductor laser, but in the package accommodating the semiconductor laser as shown in the modified examples 1 and 2 shown in FIGS. 14 and 15, for example. It is also possible to provide it in.

Since a semiconductor laser used in a HUD device is required to have a high output, it is difficult to directly use the back light monitor method generally used for a low output semiconductor laser.

Therefore, in the above embodiment, the beams emitted from the plurality of semiconductor lasers are combined and then branched, and one of the branched lights is guided to the light receiving element 117a.

However, in this case, there is a concern about the loss of the amount of light of the other branch light guided to the virtual image side of the HUD device.

Therefore, if a light source having a built-in light receiving element is used as in the first and second modifications, this problem can be alleviated.

In the first modification, as shown in FIG. 14, the beam emitted from the semiconductor laser is transmitted by a cover glass (light transmitting window member) attached to the periphery of the opening of the package so as to cover the opening. It is branched into reflected light, and the reflected light is received by the light receiving element.

Further, in the second modification of the back light monitor method, as shown in FIG. 15, the light emitted from one end surface of the semiconductor laser is radiated through the cover glass, and the light emitted from the other end surface of the semiconductor laser is emitted. By incident light on the light receiving element via the dimming element (ND filter), saturation of the amount of light in the light receiving element is suppressed.

Then, according to the light sources 3 and 4 in which the light sources of the first and second modifications are prepared for three colors of red, green, and blue as in the above embodiment, the light receiving element is provided for each light source. In the light source control process and the emission light amount setting process, the light emitting elements of each light source can be turned on at the same time and the light receiving elements can receive light at the same time. In this case, the amount of emitted light can be set in a shorter time.

Further, in the above-described embodiment and the wavelength estimation method of each modification, a light source device having a plurality of light sources has been described as an example, but as in the modification 5 shown in FIG. 16, a single light source is provided. It can also be applied to light source devices. Even when a single light source is used, the amount of emitted light from the light source can be set accurately by estimating the wavelength of the emitted light with high accuracy. Applications of a light source device having a single light source (for example, a semiconductor laser) include, for example, an image display device for displaying a monochrome image, a laser processing machine, a laser annealing device, a laser spark plug, and the like.

In this case, the wavelength of the emitted light of the light source is estimated by the wavelength estimation unit, the amount of emitted light is calculated by the power setting unit based on the estimation result, and the modulation signal is generated by the modulation signal generation unit based on the calculation result. Therefore, the light source can be turned on with a desired amount of emitted light.

Further, the image display device of the present invention can be applied not only to a HUD device but also to, for example, a head-mounted display device, a prompter device, and a projector device. In this case as well, it is possible to display an image of a desired color.

For example, when applied to a projector device, the projector device can be configured in the same manner as the HUD device 100. That is, the image light through the concave mirror 40 may be projected onto a projection curtain, a wall surface, or the like. The image light passing through the screen 30 may be projected onto a projection curtain, a wall surface, or the like without providing the concave mirror 40. Further, a free curved mirror may be used instead of the concave mirror 40.

Further, the light source device provided with the light source and the wavelength estimation device of the present invention can also be used as an exposure light source for an image forming device such as a color printer or a color copier that exposes a photoconductor to form an image. In this case as well, it is possible to form an image of a desired color.

In the above explanation, the wavelength of the emitted light is estimated from both the atmospheric temperature dependence and the self-temperature dependence of the wavelength of the emitted light of the semiconductor laser. For example, in an environment where the atmospheric temperature of the semiconductor laser can be regarded as substantially constant. As a modification 6, the wavelength of the emitted light may be estimated based only on the self-temperature dependence (only the amount of light received by the light receiving element 117a or the amount of averaged light). In this case, the temperature sensor 130 and the detection means may not be provided.

Here, "in an environment where the atmospheric temperature of the semiconductor laser can be regarded as substantially constant" means that the temperature inside the vehicle on which the HUD device 100 is mounted is kept substantially constant by air conditioning, or the light source of the present invention and the light source of the present invention. When a head-mounted display device, a prompter device, or a projector device as an image display device including a light source device including a wavelength estimation device is used indoors, it is assumed that the temperature in the room is kept substantially constant by air conditioning. To.

Specifically, the wavelength of the emitted light can be estimated using the following equation (2).

λ = λ ⁽⁰⁾ + β × (PP ⁽⁰⁾ )… (2)
However, λ: current wavelength λ ⁽⁰⁾ : reference wavelength β: light intensity coefficient P: current emission light intensity P ⁽⁰⁾ : emission light intensity at the time of reference wavelength measurement

In this case as well, the reference wavelength can be obtained in the same manner as in the above embodiment (see FIG. 11). In this case, in the semiconductor laser that oscillates in the vertical multimode, the wavelength to be estimated may be, for example, the weighted average wavelength or the wavelength at the peak intensity.

The wavelength estimation device of the above-described embodiment and each modification described above is a wavelength estimation device that estimates the wavelength of light from a light source, and is a light detector that receives light from a light source and the light detector. It includes a wavelength estimation unit that estimates the wavelength of light from a light source based on the amount of received light.

In this case, the wavelength can be estimated accurately without introducing a method of directly measuring the wavelength from the light source (for example, a superheterodyne method using an optical bandpass filter).

That is, with a simple configuration, the wavelength of light from the light source can be estimated with high accuracy.

Further, the wavelength estimation device of the above-described embodiment and each modification further includes a signal processing unit that time-averages the signal according to the amount of light received from the photodetector, and the wavelength estimation unit is time-averaged from the signal processing unit. It is preferable to estimate the wavelength of light from the light source based on the signal.

In this case, the wavelength of the light from the light source can be estimated more accurately.

Further, the wavelength estimation devices of the above-described embodiments and modifications 1 to 5 further include a detection system (temperature sensor 130 and the above-mentioned detection means) for detecting the ambient temperature around the light source, and the wavelength estimation unit detects the amount of received light and the detection. It is preferable to estimate the wavelength of light from the light source based on the ambient temperature detected by the system.

In this case, the wavelength of the light from the light source can be estimated more accurately.

Further, it is preferable that λ = λ ⁽⁰⁾ + α × (T _{a −} T _a ⁽⁰⁾ ) + β × (PP ⁽⁰⁾ ) is established.
However, λ: current wavelength λ ⁽⁰⁾ : reference wavelength α: temperature coefficient T _a : current atmospheric temperature _Ta ⁽⁰⁾ : atmospheric temperature at the time of reference wavelength measurement β: light amount coefficient P: current emission light amount P ^{( 0)} : Amount of emitted light when measuring the reference wavelength

Further, it is preferable that the reference wavelength λ ⁽⁰⁾ is a virtual wavelength at P ⁽⁰⁾ = 0 [W].

Further, the light source includes a semiconductor laser, the semiconductor laser oscillates in the vertical multimode, and the reference wavelength λ ⁽⁰⁾ is a weighted average of wavelength components having an intensity of −20 dB or more of the peak intensity in the vertical multimode. It is preferably a wavelength.

Further, according to the light source device including the light source including the light emitting element and the wavelength estimation device of the above-described embodiment and each modification for estimating the wavelength of the light from the light source, the wavelength of the light from the light source is estimated with high accuracy. The amount of light emitted from the light source can be appropriately controlled based on the estimation result. As a result, light of a desired color can be generated with good reproducibility.

Further, the light source device further includes an LD driver (drive circuit) for driving the light source, and the temperature sensor 130 of the wavelength estimation device may be arranged at a position where the detected atmospheric temperature is not easily affected by the heat generated by the LD driver. preferable.

Further, in the above embodiment and the sixth modification, there are a plurality of (for example, three) light sources, and the light emitting elements of the plurality of light sources have different emission wavelength bands, synthesize light from the plurality of light sources, and combine the combined light. Further provided with a branched optical system, the light receiving element is arranged on the optical path of the branched light from the optical system, and the light source device is a plurality of light sources based on the wavelengths of light from the plurality of light sources measured by the wavelength estimation device. Further, it is provided with a light emitting light amount setting means for setting the light emitting light amount of the light emitting element.

Further, in the above modifications 1 and 3, the light source further includes a package (accommodating body) provided with a cover glass (light transmitting window member) for accommodating the light emitting element, and the light from the light emitting element is the cover glass. It is divided into transmitted light and reflected light, and the light receiving element of the wavelength estimation device is housed in a package so as to receive the reflected light.

Further, in the above modifications 2 and 4, the light emitting element is an end face light emitting type semiconductor laser, and the light source further includes a package (accommodating body) provided with a cover glass for accommodating the semiconductor laser, and the semiconductor laser. The light from one end surface is radiated to the outside of the package through the cover glass, and the light receiving element of the wavelength estimation device is housed in the package so as to receive the light from the other end surface of the semiconductor laser.

Further, in the above modifications 2 and 4, it is preferable that the dimming element is arranged on the optical path between the other end surface of the semiconductor laser and the light receiving element in the package.

Further, in the above modifications 3 and 4, there are a plurality of (for example, three) light sources, a plurality of light receiving elements corresponding to the plurality of light sources, and the light emitting elements of the plurality of light sources have different emission wavelength bands. Further, it is provided with an emission light amount setting means for setting the emission light amount of the plurality of semiconductor lasers based on the wavelengths of the light from the plurality of semiconductor lasers estimated by the wavelength estimation device.

Further, the HUD device 100 includes a light source device, a light deflector 15 (image forming element) that forms an image by light from the light source device, and a screen 30 that is irradiated with the light that forms the image. .. In this case, the image can be drawn on the screen 30 with good color reproducibility.

Further, a HUD device 100 further provided with a concave mirror 40 (light projecting unit) that projects light through the screen 30 toward the front windshield 50 (transmissive reflection member), an automobile on which the HUD device 100 is mounted, and an automobile. According to the moving body device including the above, a virtual image having excellent visibility can be displayed to the driver.

Further, the wavelength estimation method of the above-described embodiment and each modification is a wavelength estimation method for measuring the wavelength of light from a light source, and is based on a step of receiving light from a light source and a light receiving result in the step of receiving light. It includes a step of estimating the wavelength of light from a light source based on it.

In this case, the wavelength can be estimated accurately without introducing a method of directly measuring the wavelength from the light source (for example, a superheterodyne method using an optical bandpass filter).

That is, with a simple configuration, the wavelength of light from the light source can be estimated with high accuracy.

The wavelength estimation methods of the above-described embodiments and modifications 1 to 5 further include a step of detecting the ambient temperature around the light source, and in the step of estimating, the wavelength estimation method from the light source is based on the detection result and the light reception result in the detection step. Estimate the wavelength of light.

In this case, the wavelength of the light from the light source can be estimated more accurately.

Further, the light source control methods of the above-described embodiments and modifications 3, 4 and 6 are light source control methods for controlling a plurality of light sources having different emission wavelengths, and are a step of causing a plurality of light sources to emit light and a process of emitting light from the plurality of light sources. Based on the step of receiving light, the step of estimating the wavelength of light from a plurality of light sources based on the result of receiving light in the step of receiving light, and the step of estimating the wavelength of light from a plurality of light sources, and the step of estimating the amount of light emitted by a plurality of semiconductor lasers Including the setting process.

In this case, light of a desired color can be generated with good reproducibility.

Further, the light source control methods of the above-described embodiments and modifications 1 to 5 further include a step of detecting the ambient temperature around a plurality of light sources, and the estimation step is based on the detection result and the light receiving result in the detecting step. Estimate the wavelength of light from the light source.

In this case, light of a desired color can be generated with better reproducibility.

For example, in the light source devices of the above-described embodiments and modifications 5 and 6, a plurality of light receiving elements corresponding to at least one light source may be provided. Specifically, the light from at least one light source may be branched, one branched light may be received by the corresponding light receiving element, and the other branched light may be combined and used for image display.

Further, in the above embodiment and each modification, the light projecting portion is composed of the concave mirror 40, but the present invention is not limited to this, and may be composed of, for example, a convex mirror.

Further, in the above-described embodiment and each modification, the scanning mirror 20 is provided, but it may not be provided. That is, the light deflected by the light deflector 15 may be directly irradiated to the screen 30 or irradiated through a convex lens without folding back the optical path. Further, a plane mirror may be used as the scanning mirror 20.

Further, although the LD is used as the light emitting element in the above embodiment and each modification, for example, another laser such as VCSEL, an LED, an organic EL element, a light emitting element such as a white light source may be used.

Further, the transmission / reflection member is not limited to the windshield of the moving body, and may be, for example, a side glass, a rear glass, or the like. In short, the transmission / reflection member is provided on the moving body, and the passenger of the moving body is the moving body. It is preferable that the window member (windshield) for visually recognizing the outside of the windshield.

Further, in the above-described embodiment and each modification, the image display device (HUD) has been described as being mounted on a moving body such as a vehicle, an aircraft, a ship, or a robot, but the point is that the image display device (HUD) is mounted on an object. If it is good. In addition to moving objects, "objects" include objects that are permanently installed and objects that can be transported.

Further, the wavelength estimation device, the light source device, the image display device, and the object device of the present invention are not limited to the configurations described in the above-described embodiment and each modification, and can be appropriately changed.

11 ... Light source unit, 15 ... Light deflector (image forming element), 30 ... Screen, 40 ... Concave mirror (light projection unit), 50 ... Front windshield (transmissive reflection member), 100 ... HUD device (image display device) , 118 ... Reflective mirror (part of optical system), 114 ... Optical path synthesis element (part of optical system), 115 ... Optical path synthesis element (part of optical system), 111R, 111G, 111B ... Light emitting element (light source) , 700a ... Wavelength estimation unit (estimation means), 700b ... Power balance determination unit (emission light amount setting means), 6111 ... LD driver (drive circuit).

Japanese Patent No. 5304380 JP 2015-148665

Claims (15)

A wavelength estimation device that estimates the wavelength of light from a light source.
A photodetector that receives light from the light source and
A detection system that detects the ambient temperature around the light source,
The amount of light received by the photodetector , the ambient temperature detected by the detection system, and the formula λ = λ (0) + α × (Ta-Ta (0)) + β × (PP (0)). A wavelength estimation device including an estimation means for estimating the wavelength based on the above.
However, λ: current wavelength
λ (0): Reference wavelength
α: Temperature coefficient
Ta: Current ambient temperature
Ta (0): Atmospheric temperature at the time of reference wavelength measurement
β: Light intensity coefficient
P: Current amount of emitted light
P (0): Amount of emitted light when measuring the reference wavelength Further, a signal processing unit for time-averaging signals according to the amount of received light from the photodetector is provided.
The wavelength estimation device according to claim 1, wherein the estimation means estimates the wavelength based on a time-averaged signal from the signal processing unit. The light source includes a semiconductor laser.
The semiconductor laser oscillates in vertical multimode.
The wavelength estimation device according to claim 1 , wherein the reference wavelength λ (0) is a wavelength obtained by weighted averaging wavelength components having an intensity of −20 dB or more of the peak intensity in the vertical multimode. A light source including a light emitting element and
A light source device comprising the wavelength estimation device according to any one of claims 1 to 3 , which estimates the wavelength of light from the light source. Further provided with a drive circuit for driving the light source,
The detection system of the wavelength estimation device includes a temperature sensor.
The light source device according to claim 4 , wherein the temperature sensor is arranged at a position where the ambient temperature detected by the temperature sensor is not easily affected by heat generated by the drive circuit. There are multiple light sources,
The light emitting elements of the plurality of light sources have different emission wavelength bands.
An optical system that synthesizes light from the plurality of light sources and branches the combined light is further provided.
The photodetector of the wavelength estimation device is arranged on the optical path of the branched light from the optical system.
4. The fourth or fifth aspect of the present invention is characterized in that the emission light amount setting means for setting the emission light amount of the plurality of light emitting elements is further provided based on the wavelengths of the light from the plurality of light sources estimated by the wavelength estimation device. The light source device described. The light source further includes an accommodating body having a light transmitting window member accommodating the light emitting element.
The light from the light emitting element is branched into transmitted light and reflected light by the light transmitting window member.
The light source device according to claim 4 or 5 , wherein the photodetector of the wavelength estimation device includes a light receiving element housed in the housing so as to receive the reflected light. The light emitting element is an end face light emitting type semiconductor laser.
The light source further includes an accommodating body having a light transmitting window member accommodating the semiconductor laser.
The light from one end surface of the semiconductor laser is radiated to the outside of the housing through the light transmitting window member.
The light source device according to claim 4 or 5 , wherein the photodetector of the wavelength estimation device includes a light receiving element housed in the housing so as to receive light from the other end surface of the semiconductor laser. .. The light source device according to claim 8 , further comprising a dimming element arranged on an optical path between the other end surface of the semiconductor laser and the light receiving element in the housing. There are multiple light sources,
There are a plurality of the photodetectors corresponding to the plurality of light sources.
The light emitting elements of the plurality of light sources have different emission wavelength bands.
The invention according to claim 7 to 9 , further comprising a light emitting light amount setting means for setting the emission light amount of the plurality of light emitting elements based on the wavelengths of light from the plurality of light sources estimated by the wavelength estimation device. The light source device according to any one item. The light source device according to any one of claims 4 to 10 .
An image forming element that forms an image with light from the light source device,
An image display device including a screen on which the light forming the image is irradiated. The image display device according to claim 11 , further comprising a light projecting unit that projects light through the screen toward the transmission / reflection member.
An object device including an object on which the image display device is mounted. The object device according to claim 12 , wherein the object is a moving body. A wavelength estimation method that measures the wavelength of light from a light source.
The process of receiving light from the light source and
The process of detecting the ambient temperature around the light source and
The light receiving result in the light receiving step, the atmospheric temperature detected in the detecting step, and the formula λ = λ (0) + α × (Ta−Ta (0)) + β × (PP (0)) , wavelength estimation method comprising the steps of estimating the wavelength based on.
However, λ: current wavelength
λ (0): Reference wavelength
α: Temperature coefficient
Ta: Current ambient temperature
Ta (0): Atmospheric temperature at the time of reference wavelength measurement
β: Light intensity coefficient
P: Current amount of emitted light
P (0): Amount of emitted light when measuring the reference wavelength A light source control method that controls multiple light sources with different emission wavelengths.
The process of causing the plurality of light sources to emit light, and
The process of receiving light from the plurality of light sources and
The process of detecting the ambient temperature around the light source and
The light receiving result in the light receiving step, the atmospheric temperature detected in the detecting step, and the formula λ = λ (0) + α × (Ta−Ta (0)) + β × (PP (0)) , And the process of estimating the wavelength of light from the plurality of light sources based on
A light source control method including a step of setting emission light amounts of the plurality of light sources based on an estimation result in the estimation step.
However, λ: current wavelength
λ (0): Reference wavelength
α: Temperature coefficient
Ta: Current ambient temperature
Ta (0): Atmospheric temperature at the time of reference wavelength measurement
β: Light intensity coefficient
P: Current amount of emitted light
P (0): Amount of emitted light when measuring the reference wavelength

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