JP6380797B2 - Head-up display device - Google Patents

Description

The present invention relates to a head-up display device using a laser light source.

A laser beam is emitted, and a scanning unit scans the laser beam in a two-dimensional direction to generate an image. By projecting this image onto a reflection / transmission surface such as a windshield or a combiner mounted on the vehicle, the vehicle Patent Document 1 discloses a head-up display device capable of visually recognizing a front real scene and an image while suppressing movement of an observer's line of sight.

As a head-up display device, it can display images with high brightness so that it can be clearly seen even in a bright environment in the daytime, and low brightness images that do not look dazzling even in a dark environment at night It is required that it can be displayed. In order to realize such a display with a wide luminance range, Patent Document 1 describes the light intensity of laser light by adjusting the polarization angle of the laser light emitted from the laser light source and adjusting the voltage applied to the polarization control element. What is appropriately attenuated (dimmed) is described.

JP 2009-244797 A

However, a vehicle equipped with such a head-up display device may enter or exit a tunnel or the like. For example, when a vehicle enters a tunnel, a polarization control element is displayed to display an image having a luminance suitable for a dark environment. It is necessary to rapidly increase the voltage applied to the laser beam and rapidly decrease the laser beam transmitted through the polarization control element.

By the way, as a method of generating an applied voltage to be applied to the polarization control element, a digital signal is generated based on the light intensity data of the outside light intensity sensor of the vehicle, and an applied voltage that is an analog signal is obtained by performing DA conversion on the digital signal. However, if a digital signal that changes rapidly due to changes in the intensity of external light is converted from digital to analog, ripples will occur, causing fluctuations in dimming, and configuring the circuit to suppress this ripple. In this case, there is a problem that the analog signal to be output cannot quickly respond to a sudden change in the digital signal.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a head-up display device capable of quickly controlling light control and generating an image with stable luminance.

  In order to achieve the above object, a head-up display device according to a first aspect of the present invention includes a laser light source that emits laser light, a scanning unit that scans the laser light to generate an image, and the laser light source; A dimming unit arranged between the scanning unit and dimming the laser light and directing the laser beam to the scanning unit; a control unit outputting a pulse signal for controlling dimming of the dimming unit; and the control unit A dimming control unit that converts the pulse signal from the analog signal into an analog signal and drives the dimming unit with the analog signal, wherein the dimming control unit converts the pulse signal into an analog signal. An integration circuit; and a second integration circuit connected to an output side of the first integration circuit and having a ripple voltage set lower than that of the first integration circuit.

According to the present invention, it is possible to provide a head-up display device that can quickly perform dimming control and can generate an image with stable luminance.

It is a figure for demonstrating the mounting aspect of the head-up display (HUD) apparatus which concerns on 1st Embodiment of this invention. It is a schematic block diagram of the HUD apparatus which concerns on the said embodiment. It is a figure for demonstrating the structure of a synthetic | combination laser beam emission part, a light control part, and a photon detection part. It is a figure for demonstrating a mode that an image is scanned on a screen. It is a figure which shows the time transition of the scanning of a MEMS mirror, (a) is a figure which shows the time transition of a vertical scanning position, (b) is a figure which shows the time transition of a horizontal scanning position. It is a figure for demonstrating the electrical structure of the HUD apparatus which concerns on the said embodiment. It is a figure which shows the structure of the waveform conversion part which concerns on the said embodiment. It is a figure for demonstrating the light control digital signal in the said embodiment. It is a figure for demonstrating the light control analog signal in the said embodiment. It is a figure for demonstrating the ripple voltage of the 1st waveform conversion part of the waveform conversion part in the said embodiment, and a 2nd waveform conversion part. It is a figure for demonstrating the electrical constitution of the HUD apparatus which concerns on 2nd Embodiment. It is a figure for demonstrating arrangement | positioning of the resistor for voltage adjustment with which the light control part of 3rd Embodiment is provided. It is a figure for demonstrating the effect | action of the resistor for voltage adjustment in the said embodiment, and is a figure which shows the dimming voltage signal based on the change of the duty ratio of the dimming digital signal which a dimming control part inputs. It is a figure which shows the difference in the transmittance | permeability of each color laser beam in a light control part. It is a figure which shows the modification of arrangement | positioning of the resistor for voltage adjustment in the said embodiment.

First Embodiment A first embodiment of a head-up display device (hereinafter referred to as a HUD device) of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram for explaining a mounting mode of a head-up display (HUD) device according to this embodiment, and FIG. 2 is a schematic configuration diagram of the HUD device according to this embodiment.

As shown in FIG. 1, the HUD device 1 in the present embodiment is disposed on the dashboard of the vehicle 2 and emits display light K toward the windshield 3. The display light K reflected by the windshield 3 is visually recognized by the user 4 (mainly the driver of the vehicle 2) as a virtual image V in front of the windshield 3. In this way, the HUD device 1 displays the virtual image V for the user 4. The display light K represents a predetermined image M (see FIG. 2). The image M is, for example, an image for notifying information about the vehicle 2 (hereinafter, vehicle information).

As shown in FIG. 2, the HUD device 1 includes a synthetic laser beam emitting unit 10, a light control unit 20, a light detection unit 30, a light scanning unit 40, a screen 50, a first reflection unit 60, 2 reflection part 70, case 80, and external light detection part 90 are provided.

The synthetic laser beam emitting unit 10 emits a synthetic laser beam P, which will be described later, toward the optical scanning unit 40. As shown in FIG. 3, a laser diode (LD) 11, a condensing unit 12, and a multiplexing unit are used. Part 13.

The LD 11 includes a red LD 11a that emits red laser light, a green LD 11b that emits green laser light, and a blue LD 11c that emits blue laser light. Each of the LDs 11a to 11c emits light at a predetermined light intensity and timing by a drive current supplied from a light source control unit 100 described later.

The condensing unit 12 condenses each of the synthetic laser beams P emitted from the LD 11 and reduces the spot diameter to be converged light. Specifically, the condensing part 12 is comprised from the condensing parts 12a-12c which each consist of a lens etc. The condensing part 12a is located on the optical path of the laser light emitted from the red LD 11a, the condensing part 12b is located on the optical path of the laser light emitted from the green LD 11b, and the condensing part 12c is located on the optical path of the laser light emitted from the blue LD 11c. Located in.

The combining unit 13 emits a single combined laser beam P by aligning the optical axes of the laser beams emitted from the LD 11 and reaching via the condensing unit 12. The combining unit 13 includes a reflecting unit 13a made of a plane mirror or the like, a combining unit 13b and a combining unit 13c made of a dichroic mirror or the like that each reflects light of a specific wavelength but transmits light of other wavelengths, It is composed of

The light control unit 20 includes a liquid crystal panel (not shown), a pair of polarizing filters (not shown) that sandwich the liquid crystal panel, and the like, and is positioned between the combined laser light emitting unit 10 and the optical scanning unit 40, which will be described later. Under the control of the dimming control unit 200, the transmittance of the synthetic laser light P from the synthetic laser light emitting unit 10 is changed to adjust the amount of the synthetic laser light P incident on the optical scanning unit 40. (Dimming). The liquid crystal panel is, for example, a VA (Vertical Alignment) type liquid crystal element, and the polarizing filter is configured by a reflective aluminum wire grid polarizing filter or the like.

The light control unit 20 can arbitrarily control the polarization angle of the synthetic laser light P in a range of 0 to 90 ° by controlling the magnitude of the voltage applied to the liquid crystal panel (PAM (Pulse Amplitude Modulation) control). The transmittance (light control rate) of the synthetic laser light P in the light control unit 20 is controlled. Thereby, the light intensity of the synthetic laser light P passing through the light control unit 20 can be arbitrarily determined.
Further, in the present embodiment, a normally black liquid crystal that cuts off laser light when the applied voltage of the liquid crystal panel is used in an off state and transmits laser light when used in an on state is used as an example. You may comprise with a White liquid crystal.

In addition, the liquid crystal panel of the light control unit 20 is not sandwiched between a pair of polarizing filters as in the present embodiment, but as a modification, the polarizing filter is disposed only in the rear stage (away from the LD 11) of the liquid crystal panel. It may be. This is because laser light is emitted from the LD 11 with a certain polarization direction, and can be achieved by adjusting the polarization direction of the LD 11 and the polarization direction of the polarizing filter.

In the present embodiment, the synthesized laser light P is incident on the light control unit 20 and the red laser light, the green laser light, and the blue laser light are adjusted by the same light control unit 20, but as a modification, The dimming unit 20 may be disposed between each LD 11 and each multiplexing unit 13, and each of the red laser light, the green laser light, and the blue laser light may be dimmed by the individual dimming unit 20. The above is a modification of the light control part 20 of this embodiment, and the structure of the HUD apparatus 1 is demonstrated again with reference to FIGS.

The light detection unit 30 includes a photodiode or the like, and receives light reflected by the transmission film 31 (hereinafter referred to as reflected light P <b> 1) among the synthetic laser light P. The light detection unit 30 detects the light intensity (for example, luminance) of the laser light from the received reflected light P1, and outputs the detected light intensity to the main control unit 300 described later. Specifically, the light detection unit 30 outputs a detection signal (voltage) corresponding to the light intensity of each synthetic laser beam P to the main control unit 300 as data indicating the light intensity (light intensity data).

The transmissive film 31 is made of a transmissive member having a reflectivity of about 5%, for example, and is located between the light control unit 20 and the optical scanning unit 40. The transmission film 31 transmits most of the synthetic laser light P emitted from the synthetic laser light emitting unit 10 and transmitted through the dimming unit 20 as it is, but reflects part of the light toward the light detection unit 30 ( Reflected light P1). The synthetic laser light P that has passed through the transmission film 31 enters the optical scanning unit 40.

The optical scanning unit 40 is configured by a MEMS (Micro Electro Mechanical System) mirror or the like. Under the control of a scanning control unit 400 described later, the synthetic laser light P is applied onto a screen 50 described later as shown in FIG. An image M is generated by performing vertical scanning while performing horizontal scanning.

The screen 50 displays the image M on the front side by receiving the synthesized laser beam P from the optical scanning unit 40 on the back side and transmitting and diffusing it. The screen 50 includes a holographic diffuser, a microlens array, a diffusion plate, and the like.

As shown in FIG. 4, the screen 50 is divided into a display area 50a, which is an area where the image M is displayed, and a non-display area 50b, which is an area where the image M is not displayed. That is, the display area 50 a is an area corresponding to the display light K emitted to the outside of the HUD device 1 and is an area that can be visually recognized by the user 4 as the virtual image V. The non-display area 50b is an area that the user 4 cannot visually recognize.

As shown in FIG. 4, the optical scanning unit 40 scans the synthetic laser beam P from the scanning start position F1 to the scanning end position F4 of the screen 50 (see the solid line indicated by the symbol P), and the scanning end position F4. When the value reaches, scanning returns to the scanning start position F1 again. As shown in FIG. 5A, the scanning period of the optical scanning unit 40 includes an actual scanning period Fa, which is a period during which the display area 50a and the non-display area 50b are scanned, and a scanning start position F1 from the scanning end position F4. It is classified into a retrace line period Fb which is a period returning to. A frame period (one frame), which is a period from when the optical scanning unit 40 starts scanning from the scanning start position F1 to returning to the scanning start position F1, is 1 so that the flicker due to the period is not recognized by the user 4. / Set to less than 60 seconds.

The first reflection unit 60 is made of a plane mirror or the like, and reflects the display light K representing the image M displayed on the screen 50 toward the second reflection unit 70.

The second reflecting unit 70 is formed of a concave mirror or the like, and reflects the display light K from the first reflecting unit 60 toward the windshield 3. The display light K reflected by the second reflecting portion 70 reaches the windshield 3 via a light transmitting portion 81 described later.

The housing 80 accommodates the above-described parts (the synthetic laser light emitting part 10 to the second reflecting part 70), and is formed of a light-shielding member. The housing 80 is formed with an opening through which the display light K reflected by the second reflecting unit 70 passes. A translucent part 81 is provided in the opening.

The light transmitting portion 81 is made of a light transmitting resin such as acrylic and transmits the display light K reflected by the second reflecting portion 70. The translucent part 81 is formed in a curved shape so that external light is not reflected in the direction of the user 4.

The external light detection unit 90 is disposed on the inner surface of the translucent unit 81, detects external light intensity (for example, illuminance), and sends data indicating the detected external light intensity (external light intensity data) to the main control unit 300. Output.

Next, the electrical configuration of the HUD device 1 will be described.

In addition to the above configuration, the HUD device 1 includes a light source control unit 100, a dimming control unit 200, a main control unit 300, and a scanning control unit 400, as shown in FIG. These control units are mounted, for example, on a printed circuit board (not shown) disposed in the housing 80. Note that these control units may be provided outside the housing 80.

The light source control unit 100 drives and controls the LD 11 and includes a drive unit 110 and a power feeding unit 120.

The drive unit 110 includes a driver IC (Integrated Circuit) and the like, and drives each of the LDs 11a to 11c by a PAM (Pulse Amplitude Modulation) method and a PWM (Pulse Width Modulation) method under the control of the main control unit 300. To do. The drive unit 110 supplies a drive current having a current value based on a control signal from the main control unit 300 to each of the LDs 11a to 11c.

The power feeding unit 120 supplies power to the LD 11 via the driving unit 110, and includes a power supply IC, a switching circuit using a transistor, and the like. The power supply unit 120 switches between supply and non-supply of power to each of the LDs 11 a to 11 c under the control of the main control unit 300. In addition, the electric power feeding part 120 may be independently provided in each of LD11a-11c, and may be shared by these.

The dimming control unit 200 is a waveform converting unit 210 that converts a dimming digital signal output from the main control unit 300 described later into a dimming analog signal, and a voltage value of the dimming analog signal by inputting the dimming analog signal. And a gain adjusting unit 220 that outputs a dimming control voltage.

The dimming control unit 200 generates a predetermined applied voltage (dimming control voltage) to be applied to the dimming unit 20 under the control of the main control unit 300, and adjusts the voltage value of the dimming control voltage ( PAM control) adjusts the transmittance of the synthetic laser light P in the light control unit 20 (light control). Specific configurations and operations of the waveform conversion unit 210 and the gain adjustment unit 220 will be described in detail later.

The main control unit 300 includes a processing unit 310 having one or more microprocessors, controllers, microcontrollers, ASICs, FPGAs, arbitrary other ICs (not shown), a rewritable RAM (not shown), and a read-only memory. A storage unit 320 having one or a plurality of memories capable of storing programs and data, such as a ROM as a memory, an EEPROM as an erasable program read-only memory, and a flash memory as a nonvolatile memory.

The storage unit 320 stores programs and various data necessary for the operation of the HUD device 1. The storage unit 320 stores in advance dimming table data in which external light intensity data and dimming digital signals are associated with each other.

The processing unit 310 reads each program from the storage unit 320 and executes it to control each unit. Specifically, the processing unit 310 inputs an information signal from a vehicle side (not shown), reads out image data based on the information signal, and controls the light source control unit 100 and the scanning control unit 400 to control the screen 50. An image M is generated. In addition, the processing unit 310 receives the external light intensity data from the external light detection unit 90, determines the dimming digital signal Sa based on the dimming table data stored in the storage unit 320, and sends it to the waveform conversion unit 210. The light control digital signal Sa is output, and the light control unit 20 is controlled via the light control unit 200 to execute “light control processing” of the combined laser light P. Details of the “light control processing” will be described later.

The scanning control unit 400 drives the optical scanning unit 40 and includes a driving unit 410 and a mirror position detection unit 420.

The driving unit 410 includes a driver IC and the like, and drives the optical scanning unit 40 under the control of the main control unit 300. After driving the optical scanning unit 40, the driving unit 410 acquires the scanning position detection data output from the mirror position detection unit 420, calculates feedback data based on the acquired scanning position detection data, and uses the feedback data as the feedback data. Output to the main control unit 300. The feedback data output from the drive unit 410 includes horizontal scanning switching data indicating the reciprocal switching timing of horizontal scanning, and scanning period data in which the scanning period indicates either the actual scanning period Fa or the blanking period Fb. .

The feedback data is mainly used for the processing unit 310 to specify the scanning position of the optical scanning unit 40. The processing unit 310 counts the number of horizontal scanning lines based on the horizontal scanning switching data of the feedback data. Based on this count number, the processing unit 310 identifies the scanning position of the optical scanning unit 40 and determines the current scanning area.

The mirror position detection unit 420 detects the shake position of the piezo element that moves the mirror of the optical scanning unit 40 for each time, and outputs the detected position to the drive unit 410 as scanning position detection data.

From here, the specific configuration and operation of the dimming control unit 200 (the waveform converting unit 210 and the gain adjusting unit 220) in the present embodiment will be described.

The waveform converter 210 receives the dimming digital signal Sa that is a digital signal output from the main control unit 300 determined based on the external light intensity data from the external light detection unit 90, and is a dimming that is an analog signal. The analog signal Sb is output. As shown in FIG. 7, the first waveform converter 211 and the second waveform converter 212 are connected in series.

The first waveform converter 211 is an integrating circuit having a first resistor 211a and a first capacitor 211b. The main controller 300 is connected to the input line, and the second waveform converter 212 is connected to the output line. The The CR time constant of the first resistor 211a and the first capacitor 211b is determined with emphasis on responsiveness.

The second waveform converter 212 is an integrating circuit having a second resistor 212a and a second capacitor 212b. The output line of the first waveform converter 211 is connected to the input line, and the gain is adjusted to the output line. The input line of the unit 220 is connected. The CR time constant of the second resistor 212a and the second capacitor 212b is determined with emphasis on voltage stabilization.

なお、第１波
形変換部２１１によるリップル電圧Ｖｒ１を求める場合、入力電圧Ｖｉｎは、主制御部３００から入力する調光デジタル信号Ｓａのハイ電圧ＶＨ（図８参照）となる。また、第２波形変換部２１２によるリップル電圧Ｖｒ２を求める場合、入力電圧Ｖｉｎは、第１波形変換部２１１から入力する電圧信号のリップル電圧Ｖｒ１となる。 When the pulse signal (the dimming digital signal Sa) is input to the first waveform conversion unit 211 including an integration circuit, the first waveform conversion unit 211 outputs a voltage signal having the ripple voltage Vr1. Further, since the voltage signal having the ripple voltage Vr1 is also input from the first waveform converting unit 211 to the second waveform converting unit 212, the voltage signal (the dimming analog signal) having the ripple voltage Vr2 is also input from the second waveform converting unit 212. Sb) is output. Since the second waveform converter 212 works to suppress the ripple voltage Vr1 of the first waveform converter 211, the ripple voltage Vr2 of the voltage signal (dimming analog signal Sb) output from the second waveform converter 212 is , Becomes smaller than the ripple voltage Vr1. The ripple voltage Vr is obtained by the following equation (Equation 1), where Vin is the voltage input to the integration circuit, time is t, resistor constant is R, and capacitor constant is C.

When the ripple voltage Vr1 is obtained by the first waveform converter 211, the input voltage Vin becomes the high voltage VH (see FIG. 8) of the dimming digital signal Sa input from the main controller 300. Further, when the ripple voltage Vr <b> 2 by the second waveform conversion unit 212 is obtained, the input voltage Vin is the ripple voltage Vr <b> 1 of the voltage signal input from the first waveform conversion unit 211.

なお、リップル電圧Ｖｒ１がハイ電圧ＶＨと比べて大幅に小さいため、第２波形変換部２１２のＣＲ時定数βを、第１波形変換部２１１のＣＲ時定数αよりも小さくすることで電圧安定化を行うことが出来る。上記式（数２）を満たすように、第１波形変換部２１１のＣＲ時定数αと、第２波形変換部２１２のＣＲ時定数βとを調整することにより、波形変換部２１０の入力側（第１波形変換部２１１）の応答性を速め、出力側（第２波形変換部２１２）により電圧を安定化させることができるため、調光部２０による調光を迅速に行い、かつ安定した輝度を提供することができる。 In addition, the CR time constant α of the first waveform converter 211 (first resistor 211a and first capacitor 211b) focusing on responsiveness and the second waveform converter 212 (second resistor 212a) focusing on voltage stabilization. And the CR time constant β of the second capacitor 212b) are as follows:

Since the ripple voltage Vr1 is significantly smaller than the high voltage VH, voltage stabilization is achieved by making the CR time constant β of the second waveform converter 212 smaller than the CR time constant α of the first waveform converter 211. Can be done. By adjusting the CR time constant α of the first waveform conversion unit 211 and the CR time constant β of the second waveform conversion unit 212 so as to satisfy the above equation (Equation 2), the input side ( Since the responsiveness of the first waveform converting unit 211) can be accelerated and the voltage can be stabilized by the output side (second waveform converting unit 212), the dimming by the dimming unit 20 can be quickly performed and the luminance can be stabilized. Can be provided.

FIG. 10 is a graph showing the time transition of the ripple voltage Vr in the above equation (Equation 1). Specifically, the ripple voltage Vr2 of the second waveform converter 212 is expressed as a time t as shown in FIG. As a result, the ripple voltage Vr1 of the first waveform converter 211 is set to be suppressed to a ripple voltage Vr2 of about 1/10.

The gain adjustment unit 220 outputs a dimming voltage signal Sc having a predetermined voltage value obtained by multiplying or dividing the dimming analog signal Sb from the waveform conversion unit 210 by a predetermined magnification to the dimming unit 20. And an inverting or non-inverting amplifier circuit using an operational amplifier. In addition, by using an operational amplifier (all general operational amplifiers) having a high power supply voltage rejection ratio for the gain adjustment unit 220, voltage fluctuation of the dimming voltage signal Sc due to voltage fluctuation of the power supply (battery) of the HUD device 1 is minimized. It can be suppressed. That is, even if the voltage of the battery fluctuates, the dimming voltage signal Sc output from the gain adjustment unit 220 does not change, and a stable voltage can be supplied to the dimming unit 20. The dimming process in the present embodiment will be described below.

  First, the external light detection unit 90 detects the light intensity outside the vehicle 2 and outputs the detected external light intensity data to the main control unit 300. The processing unit 310 determines the dimming digital signal Sa based on the input external light intensity data with the dimming table data stored in the storage unit 320 below. Specifically, the dimming digital signal Sa associated with the external light intensity data is a pulse signal that repeats the high voltage VH and the low voltage VL (usually 0 V) at a predetermined ratio (duty ratio) within a certain cycle. is there. The dimming table data is data in which dimming digital signals Sa having different duty ratios are associated with a plurality of levels of external light intensity data. When the outside is bright and the outside light intensity data is large, the processing unit 310 selects the dimming digital signal Sa (Sa1) having a large duty ratio (FIG. 8A), and when the outside is dark and the outside light intensity data is small, The dimming digital signal Sa (Sa2) having a small duty ratio is selected (FIG. 8B). As the duty ratio of the dimming digital signal Sa increases, the voltage of the dimming voltage signal Sc output from the dimming control unit 200 to the dimming unit 20 also increases, and the dimming unit 20 having a normally black liquid crystal panel. Increases transmittance. As a modification, when a normally white liquid crystal panel is used for the light control unit 20, the storage unit 320 adjusts the light control so that the duty ratio of the light control digital signal Sa decreases as the external light intensity data increases. Table data is stored in advance. The frequency of the dimming digital signal Sa is set sufficiently faster (about 5 to 10 times) than the frame frequency (60 Hz) of the image.

The external light intensity data input from the external light detection unit 90 is expected to change (increase) abruptly when, for example, the vehicle 2 exits the tunnel, and based on this, the adjustment data output from the main control unit 300 is expected. The optical digital signal Sa also changes abruptly (duty ratio increases rapidly). The operation of the waveform conversion unit 210 will be described with reference to FIG. 9, where t1 is the time when the dimming digital signal Sa increases rapidly.

When the duty ratio of the dimming digital signal Sa increases abruptly at time t1, the first waveform converter 211 has a small time constant, so that the dimming is performed in response to the increase in the duty ratio of the dimming digital signal Sa. The analog signal Sb is changed at high speed from the low voltage V1 to the high voltage V2. The second waveform converter 212 connected in series to the output line of the first waveform converter 211 operates to reduce the ripple voltage Vr. Thus, even when the external light intensity changes suddenly, the voltage value of the dimming analog signal Sb can be changed abruptly by the first waveform conversion unit 211, so that the dimming of the dimming unit 20 can be performed quickly. It is possible to make the user 4 visually recognize an image M having a luminance corresponding to a sudden change in the intensity of external light. Further, even when the user 4's eyes after the external light intensity suddenly changes, the second waveform converter 212 can gradually reduce the ripple voltage Vr, so that the dimming analog signal Sb It is possible to suppress the user 4 from visually recognizing fluctuations in image luminance due to the ripple voltage Vr.

The dimming analog signal Sb output from the waveform conversion unit 210 is input to the gain adjustment unit 220. When the duty ratio of the dimming digital signal Sa from the main control unit 300 is maximum, the gain adjustment unit 220 is set near the maximum drive voltage of the liquid crystal panel of the dimming unit 20 (so that the dimming rate is maximized). D) The gain is adjusted in advance, and the dimming unit 20 is driven by outputting the dimming voltage signal Sc (dimming control voltage) obtained by amplifying the dimming analog signal Sb from the waveform converting unit 210 with a predetermined gain. To do.

  As described above, the HUD device 1 of the present embodiment includes the LD 11 that emits laser light, the optical scanning unit 40 that scans the laser light to generate the image M, and the LD 11 and the optical scanning unit 40. A dimming unit 20 arranged and dimming laser light and directing it to the optical scanning unit 40; a main control unit 300 outputting a dimming digital signal Sa (pulse signal) for controlling dimming of the dimming unit 20; A dimming control unit 200 that converts the dimming digital signal Sa from the main control unit 300 into a dimming analog signal Sb (dimming voltage signal Sc) and drives the dimming unit 20 with the dimming analog signal Sb. The dimming control unit 200 is connected to the first waveform converting unit 211 that converts the dimming digital signal Sa into an analog signal, and the output side of the first waveform converting unit 211, and the ripple voltage Vr from the first waveform converting unit 211. Second set low Having a shape conversion unit 212, a. With such a configuration, for example, even when the external light intensity changes abruptly and the dimming digital signal Sa changes abruptly, the voltage value of the dimming analog signal Sb can be changed abruptly by the first waveform conversion unit 211. Therefore, the dimming of the dimming unit 20 can be quickly performed, and the user M can visually recognize the image M having a luminance corresponding to a sudden change in the external light intensity. Further, even when the user 4's eyes after the external light intensity suddenly changes, the second waveform converter 212 can gradually reduce the ripple voltage Vr, so that the dimming analog signal Sb It is possible to suppress the user 4 from visually recognizing fluctuations in image luminance due to the ripple voltage Vr.

(2nd Embodiment) A modification is demonstrated below. FIG. 11 is a diagram illustrating an electrical configuration of the HUD device 1 in the second embodiment. The HUD device 1 in the second embodiment reverses the dimming voltage signal Sc output to the dimming unit 20. It differs from the said embodiment by the point further provided with the part 230. About the structure similar to 1st Embodiment other than that, the same code | symbol is attached | subjected and description is abbreviate | omitted.

As shown in FIG. 11, the HUD device 1 in the second embodiment connects an inverting output unit 230 between the gain adjustment unit 220 and the dimming unit 20. Note that the connection between the inversion output unit 230 and the gain adjustment unit 220 may be reversed.

The inversion output unit 230 is configured by an inverter circuit or the like, and inverts the dimming voltage signal Sc from the gain adjustment unit 220 (waveform conversion unit 210) every predetermined period and outputs the inverted voltage to the dimming unit 20 as an AC voltage. Is. In this manner, by applying an AC voltage to the light control unit 20 including the liquid crystal panel, it is possible to prevent the liquid crystal panel from being burned.

Further, the inversion output unit 230 inputs a signal for inversion switching from the main control unit 300. The main control unit 300 may determine whether it is a non-display period during which the image M such as a period during which the light scanning unit 40 scans the non-display area 50b on the screen 50 or a blanking period Fb is not generated. Is possible. When the scanning position of the optical scanning unit 40 is in the non-display area 50b, the main control unit 300 switches to the reverse output unit 230. When the light control unit 20 inverts the drive voltage, the transmittance is not constant but becomes unstable. Therefore, when the scanning position of the light scanning unit 40 is the non-display area 50b where the display is not emitted to the outside, the synthetic laser in which the appropriate light control is not performed by inverting the drive voltage of the light control unit 20 It is possible to prevent the light P from being emitted to the outside and viewed by the user 4.

Note that the main control unit 300 may determine whether it is the non-display period from the light intensity of the LD 11 detected by the light detection unit 30. That is, when the light intensity from the light detection unit 30 is small, it may be determined that the HUD device 1 is in the non-display period by determining that the LD 11 is not lit.

The light control unit 20 only needs to be able to control the synthesized laser light P under the control of the light control unit 200. Therefore, the light control unit 20 does not use a liquid crystal panel as in the above-described embodiment. ) Including a shutter, two polarizing filters, and a driving unit that rotationally drives one of the polarizing filters, and a shutter module that adjusts the synthesized laser light P by rotationally driving one of the polarizing filters. Good. In addition, the light control part 20 in these modifications can also control a light control rate rapidly by controlling according to the voltage value of the light control analog signal Sb output from the waveform conversion part 210. FIG.

(3rd Embodiment) The HUD apparatus 1 in 3rd Embodiment is demonstrated using FIG. 12 thru | or 15. FIG. FIG. 12 is a diagram for explaining the arrangement of the voltage adjusting resistors 240 included in the dimming control unit 200 of the third embodiment. One of the voltage adjusting resistors 240 is connected to the ground, and the other is connected to the output side of the waveform converting unit 210 (the input side of the gain adjusting unit 220). The voltage adjusting resistor 240 adjusts the magnitude of the dimming voltage signal Sc output by the dimming control unit 200 with respect to the dimming digital signal Sa input by the dimming control unit 200. The operation of the voltage adjusting resistor 240 will be described with reference to FIG.

FIG. 13 is a graph showing the relationship between the duty ratio D of the dimming digital signal Sa and the dimming voltage signal Sc. In FIG. 13, the dimming voltage signal Sc1 shows the case where the voltage adjusting resistor 240 is not provided, and the dimming voltage signal Sc2 shows the case where the appropriate voltage adjusting resistor 240 is provided, The dimming voltage signal Sc3 indicates a case where the resistance value of the voltage adjusting resistor 240 is too small. Also, the duty ratio Dm shown in the figure is the maximum duty ratio D of the dimming digital signal Sa output from the processing unit 310. The dimming voltage signal Scm is a voltage value necessary to maximize the transmittance of the dimming unit 20. When the voltage adjusting resistor 240 is not provided, the dimming voltage signal Sc reaches Scm when the duty ratio D of the dimming digital signal Sa reaches the duty ratio Da (Da <Dm) before reaching the Dm. Thus, even if the duty ratio D becomes larger than Da, the transmittance of the light control unit 20 does not change. That is, the transmittance of the light control unit 20 can be adjusted only within a narrow range of the duty ratio 0 to Da. In contrast, when the voltage adjustment resistor 240 is provided in the dimming control unit 200, the dimming voltage signal Sc2 gradually increases with the increase in the dimming digital signal Sa. The resistance value of the voltage adjusting resistor 240 is a dimming voltage signal Scm that maximizes the transmittance of the dimming unit 20 when the duty ratio D input by the dimming control unit 200 is maximum (Dm). To be adjusted. Thereby, the transmittance of the light control unit 20 can be adjusted in a wide range of duty ratios 0 to Dm input from the processing unit 310. That is, it is possible to increase the resolution of the light control rate of the light control unit 20 with respect to a change in external light intensity (change in the light control digital signal Sa). When the resistance value of the voltage adjusting resistor 240 is too small, the dimming voltage signal Sc3 does not reach the dimming voltage signal Scm having the dimming unit 20 as the maximum transmittance even when the duty ratio Dm is reached. As a result, the dynamic range of the dimming rate is lowered.

As described above, the HUD device 1 according to the third embodiment has a magnitude of the dimming voltage signal Sc output from the dimming control unit 200 with respect to the dimming digital signal Sa input to the dimming control unit 200. By providing the voltage adjusting resistor 240 for adjusting the light intensity, the dimming rate of the dimming unit 20 with respect to the change in the external light intensity (change in the dimming digital signal Sa) is ensured while ensuring the dynamic range of the dimming rate. The resolution can be increased.

The voltage adjusting resistor 240 is configured by a variable resistor, and the light control can be performed with higher accuracy by adjusting the resistance value of the variable resistor at the time of manufacture.

  Moreover, the light control part 20 is provided separately for each of the red laser light, the green laser light, and the blue laser light, and the light control part 200 provided with the voltage adjusting resistor 240 is provided for each light control part 20 individually. May be. As shown in FIG. 14, the transmittance of the light control unit 20 using the liquid crystal panel has different wavelength-dependent characteristics for each color of the laser light, and thus the voltage adjusting resistors 240 are individually adjusted. Specifically, the voltage for adjusting the dimming voltage signal Sc of the dimming unit 20 arranged on the optical path of the blue laser light having a short wavelength in order to suppress the difference in the transmittance of each color laser beam in the dimming unit 20. The resistance value of the adjusting resistor 240 is set to be lower than that of green or red having a long wavelength. In this way, by adjusting the resistance value of the voltage adjusting resistor 240 with the laser light of each color, it is possible to suppress variation due to the wavelength-dependent characteristics of the transmittance of the dimming unit 20. Therefore, if the white balance of the red laser light, the green laser light, and the blue laser light is adjusted by controlling the LD 11, the white balance can be maintained even after the light control unit 20 performs light control. It is also possible to adjust the variation in the transmittance of the laser light of each color in the light control unit 20 on the control side of the LD 11. However, since the control data of the LD 11 changes as appropriate according to individual variations of the LD 11 and temperature changes, it is necessary to perform a lot of correction processing to correct the control data in consideration of the variation in transmittance in the light control unit 20. It is said. According to the present embodiment, white balance can be maintained with a simple configuration in which the resistance value of the voltage adjusting resistor 240 is adjusted for each dimming unit 20.

The position to which the voltage adjusting resistor 240 is connected is not limited to the output side of the waveform converting unit 210 (the input side of the gain adjusting unit 220). For example, the gain adjustment unit 220 is configured by an operational amplifier 221 and a non-inverting amplifier circuit having feedback resistors 222 and 223, and the feedback resistor 222 or the feedback resistor 223 is configured by a variable resistor as shown in FIG. The dimming voltage signal Sc output to the dimming unit 20 may be adjusted by adjusting the resistance value of the variable resistor.

In addition, this invention is not limited by the above embodiment and the modification demonstrated from now on. Changes (including deletion of components) can be made as appropriate without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 ... HUD apparatus 10 ... Synthetic laser beam emission part 11 ... LD (laser light source) 20 ... Light control part 30 ... Light detection part 40 ... Optical scanning part 50 ... Screen 90 ... External light detection part 100 ... Light source control part 110 ... Drive Unit 120 ... Power feeding unit 200 ... Dimming control unit 300 ... Main control unit 310 ... Processing unit 320 ... Storage unit 400 ... Scanning control unit 410 ... Drive unit 420 ... Mirror position detection unit K ... Display light M ... Image P ... Synthetic laser Light Sa ... Dimming digital signal (pulse signal) Sb ... Dimming analog signal (analog signal) Sc ... Dimming voltage signal (analog signal)

Claims (6)

A laser light source that emits laser light;
A scanning unit that scans the laser beam to generate an image;
A dimming unit disposed between the laser light source and the scanning unit, dimming the laser beam and directing the laser beam to the scanning unit;
A control unit for outputting a pulse signal for controlling dimming of the dimming unit;
A dimming control unit that converts the pulse signal from the control unit into an analog signal and drives the dimming unit by the analog signal; and
The dimming control unit includes a first integration circuit that converts the pulse signal into an analog signal, and a second integration circuit that is connected to an output side of the first integration circuit and has a ripple voltage set lower than that of the first integration circuit. And having
A head-up display device. Further comprising an inversion output unit for inverting the polarity of the analog signal output from the dimming control unit at a predetermined cycle and outputting the inverted signal to the dimming unit.
The head-up display device according to claim 1. The scanning unit has a display period in which the image is displayed to the outside and a non-display period in which the image is not displayed to the outside within a frame period,
The inversion output unit inverts the analog signal when the scanning unit is in the non-display period.
The head-up display device according to claim 2. A light intensity detector that detects the light intensity of the laser light;
The inversion output unit determines non-lighting of the laser light source from light intensity data from the light intensity detection unit, and inverts the analog signal when the laser light source is not lighted.
The head-up display device according to any one of claims 2 to 3. A voltage adjusting resistor disposed between the second integrating circuit and the dimming unit and configured to adjust a magnitude of the analog signal that drives the dimming unit;
The head-up display device according to claim 1, wherein the head-up display device is a head-up display device. The laser light source is composed of a plurality of laser light sources that emit laser beams of different colors,
The light control unit is composed of a plurality of light control units respectively disposed on optical paths of laser beams of different colors emitted from the plurality of laser light sources,
The dimming control unit is provided for each of the plurality of dimming units,
The resistance value of the voltage adjusting resistor is adjusted so as to suppress the difference due to the wavelength-dependent characteristics of the transmittance of the dimmer.
The head-up display device according to claim 5.

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