JP2019139157A - Head-up display device - Google Patents

Abstract

To prevent a deterioration in performance due to external light in a head-up display device.SOLUTION: An optical unit 10 includes a display 11 that emits visible light and a plane mirror 12 and a concave mirror 13 that guide display light output from the display to a windshield 30 that is a projection target member provided in front of a driver of a vehicle, and reflects the display light on the windshield 30 to generate virtual image display that is visually recognized by the driver. A housing 20 accommodating the optical unit 10 is provided with an opening 20a for taking out the display light to the outside of the housing 20, and the opening 20a is attached with a dust-proof cover 21. The dust-proof cover 21 also functions as a light control member configured such that the transmittance of light decreases as the quantity of preset activated light increases.SELECTED DRAWING: Figure 2

Description

  The present disclosure relates to an on-vehicle head-up display device.

  A head-up that displays information superimposed on the background behind the driver's line of sight by reflecting the display light output through the liquid crystal display to the windshield of the vehicle and forming a virtual image in the front field of view of the driver of the vehicle A display (hereinafter, HUD) device is known.

In the HUD device, the temperature of the liquid crystal display or the like rises due to external light such as sunlight that passes through the windshield and enters the HUD, and the display performance deteriorates.
Japanese Patent Application Laid-Open No. 2004-228561 discloses a technique of installing a polarizing plate on an optical path from a liquid crystal display to a windshield in order to suppress performance deterioration due to external light.

JP 2017-15778 A

However, as a result of detailed studies by the inventors, the following problems have been found in the conventional technique described in Patent Document 1.
That is, in the prior art, it is not possible to obtain a sufficient temperature suppression effect for components that pass through the polarizing plate in the external light because the incident into the HUD device cannot be prevented. For this reason, it is necessary to use a combination of derating control that suppresses the current flowing to the backlight light source of the liquid crystal display and light source off control that turns off the current flowing to the backlight light source before exceeding the allowable temperature of the liquid crystal display. was there.

  One aspect of the present disclosure is to provide a technique for suppressing performance deterioration due to external light in a head-up display device.

A head-up display device according to an aspect of the present disclosure includes an optical unit (10), a housing (20), and a light control member (21).
The optical unit includes an indicator (11) that emits visible light and an optical component (12, 13) that guides display light output from the indicator to a projection member (30, 40) provided in front of a vehicle driver. And generating a virtual image display to be visually recognized by the driver by reflecting the display light on the projection member. The housing houses the optical unit. The light control member is provided in an optical path from the display device to the projection member, and the light transmittance decreases as the amount of activation light, which is light having a preset wavelength, increases.

  According to such a configuration, the greater the amount of activation light, the lower the light transmittance, and the external light reaching the display can be reduced. As a result, it is possible to suppress the heat generation of the display device based on external light, and hence the deterioration in display performance due to heat generation. Further, by suppressing the heat generation of the display, derating control and light source off control for the backlight light source of the display can be omitted.

  Note that the reference numerals in parentheses described in this column and in the claims indicate the correspondence with the specific means described in the embodiment described later as one aspect, and the technical scope of the present disclosure It is not limited.

It is a block diagram which shows the structure and operation | movement of a head-up display apparatus of 1st Embodiment. It is explanatory drawing which shows the effect | action of the head-up display apparatus with respect to external light. It is a block diagram which shows the structure of the head-up display apparatus of 2nd Embodiment. It is a block diagram which shows the structure around the display in 3rd Embodiment.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.
[1. First Embodiment]
[1-1. Constitution]
A head-up display (hereinafter, HUD) device 1 shown in FIG. 1 is mounted on a vehicle and projects display light by using a windshield or combiner positioned in front of the driver of the vehicle as a projection target member, thereby displaying the display light. It is a device that causes the driver to recognize information as a virtual image superimposed on the foreground of the vehicle. HUD is an abbreviation for Head-Up Display. In the present embodiment, the case where the windshield 30 is a projection member will be described.

  The windshield 30 incorporates an intermediate film 31 having a wedge-shaped cross section. The intermediate film 31 has a function of making the virtual image based on the display light reflected on the windshield 30 appear clear by controlling the refraction of light using the cross-sectional shape. Further, the intermediate film 31 may have a heat shielding function for cutting ultraviolet rays.

  The HUD device 1 is housed in a dashboard provided in front of the front seat of the vehicle below the windshield 30 in front of the vehicle. The HUD device 1 includes an optical unit 10 and a housing 20.

[1-1-2. Enclosure]
The housing 20 is a box-shaped object having a space for housing the optical unit 10. The housing 20 has an opening 20a for extracting display light output from the optical unit 10 to the outside on the upper surface facing the windshield 30 in a state of being attached to the dashboard. A dustproof cover 21 made of a material that transmits display light is attached to the opening 20a.

  The dust cover 21 is made of a material containing a photochromic compound (hereinafter, referred to as “photochromic compound”) that becomes darker as the amount of light increases in accordance with the amount of activation light, which is light having a preset wavelength. Dimming member). In the present embodiment, a photochromic compound containing at least visible light as the activation light is used. As a light control lens including a photochromic compound having such a function, for example, transition extra active is known. Transition Extra Active is a registered trademark.

[1-1-3. Optical unit]
The optical unit 10 includes a display 11, a plane mirror 12, and a concave mirror 13.
The display device 11 includes a liquid crystal panel 111 and a backlight light source 112. The liquid crystal panel 111 uses a TFT liquid crystal having a number of thin film-like fine transistors arranged on a glass substrate to turn on and off the pixels. TFT is an abbreviation for Thin Film Transistor. The backlight light source 112 is a light source that generates a backlight that irradiates the liquid crystal panel from the back. Light emitted from the backlight light source 112 and passed through the liquid crystal panel 111 is output as display light. The backlight light source 112 is a light emitting diode, but is not limited thereto.

The plane mirror 12 reflects the display light emitted from the display 11 toward the concave mirror.
The concave mirror 13 is a mirror for enlarging the display image formed by the display light reflected by the plane mirror 12. The concave mirror 13 reflects the display light incident from the plane mirror 12 and projects it toward the windshield 30 via the dustproof cover 21.

[1-2. Operation]
As indicated by a broken line in FIG. 1, the display light projected from the HUD device 1 through the dust cover 21 is reflected by the windshield 30 and travels toward the driver's line of sight, that is, the eye range ER. Thus, the driver recognizes the information represented by the display light as a virtual image superimposed on the foreground of the vehicle. The eye range ER is a distribution range that statistically indicates the driver's eye position.

  Here, as shown in FIG. 2, external light such as sunlight passing through the windshield 30 toward the dust cover 21 passes through the dust cover 21, is reflected by the concave mirror 13 and the plane mirror 12, and reaches the display 11. To do. External light reaching the display 11 becomes a factor for heating the display 11. Further, the external light that has reached the display 11 is reflected by the display 11 and follows the same path as the display light and travels toward the eye range ER. Hereinafter, this light is referred to as external light reflected light. The external light reflected light is reflected on the windshield 30 and becomes a factor of deteriorating the visibility of the virtual image based on the display light.

  However, since the dust-proof cover 21 is made of a light control material, the amount of external light is attenuated when it enters the housing 20 through the dust-proof cover 21, and is further reflected by the display 11. After that, the amount of light is also attenuated when the light is emitted to the outside of the housing 20 through the dust cover 21. That is, since the external light reflected light passes through the dustproof cover 21 formed of the light control material twice, it reaches the eye range ER in a sufficiently attenuated state.

[1-3. effect]
According to the first embodiment described in detail above, the following effects are obtained.
(1a) In this embodiment, since the dust-proof cover 21 is formed of a light control material, the amount of external light incident on the inside of the HUD device 1 can be suppressed. As a result, it is possible not only to suppress heat generation of the display 11 due to external light and deterioration of display performance due to heat generation, but also to omit derating control and light source off control of the backlight light source 112.

  (1b) In the present embodiment, the light-modulating material forming the dust-proof cover 21 includes visible light in the activation light. Therefore, even in an environment where the windshield 30 that cuts ultraviolet rays is used, the light control material is light according to the amount of visible light. The transmittance of can be changed.

  (1c) In the present embodiment, since the external light reflected light emitted from the HUD device 1 is sufficiently attenuated by the dust cover 21, the virtual image based on the display light by the external light reflected light being reflected on the windshield 30 It is possible to suppress the deterioration of the visibility.

[2. Second Embodiment]
[2-1. Difference from the first embodiment]
Since the basic configuration of the second embodiment is the same as that of the first embodiment, differences will be described below. Note that the same reference numerals as those in the first embodiment indicate the same configuration, and the preceding description is referred to.

  In the first embodiment described above, the backlight source 112 emits light with a constant light amount. On the other hand, the second embodiment is different from the first embodiment in that the amount of light of the backlight light source 112 is controlled according to the surrounding situation.

[2-2. Constitution]
In this embodiment, as shown in FIG. 3, in addition to the configuration shown in the first embodiment, an illuminance sensor 14, a temperature sensor 15, and a backlight control unit 16 are provided. In FIG. 3, the configuration other than the display unit 11 is omitted from the configuration shown in the first embodiment. The illuminance sensor 14 corresponds to a sensor unit, and the backlight control unit 16 corresponds to a display adjustment unit.

The illuminance sensor 14 is a sensor that measures the intensity of external light incident on the dust cover 21. For example, the illuminance sensor 14 is installed outside the housing 20 and near the dust cover 21.
The temperature sensor 15 is a sensor that measures the temperature of the liquid crystal panel 111 or the ambient temperature of the liquid crystal panel 111.

  The backlight control unit 16 controls the light amount of the backlight light source 112 according to the transmittance of the dustproof cover 21 formed by the light control member estimated from the intensity of the illuminance sensor 14. Specifically, the light amount of the backlight light source 112 is increased so as to compensate for the light amount that decreases when the display light passes through the dust cover 21 as the estimated transmittance decreases. In the control of the light amount of the backlight light source 112, the backlight control unit 16 may perform control to increase the light amount only when the temperature measured by the temperature sensor 15 is within a preset allowable range. .

[2-3. effect]
According to 2nd Embodiment explained in full detail above, there exists the effect (1a) of 1st Embodiment mentioned above, and also there exist the following effects.

(2a) It can suppress that the appearance of the virtual image based on display light deteriorates by the transmittance | permeability of the dust-proof cover 21 formed with the light control member falling.
[3. Other Embodiments]
As mentioned above, although embodiment of this indication was described, this indication is not limited to the above-mentioned embodiment, and can carry out various modifications.

  (3a) In the above embodiment, the dust cover 21 is configured to serve as a light control member, but the present invention is not limited to this. For example, a light control member may be prepared separately from the dust cover 21 and the light control member may be disposed at an arbitrary position in the optical path from the windshield 30 to the display unit 11.

  (3b) In the above embodiment, the windshield 30 is used as the projection member. However, as shown in FIG. 4, a combiner 40 may be used as the projection member instead of the windshield. The combiner 40 is a small transparent glass or resin plate-like member that is installed between the windshield 30 and the vehicle driver. In this case, by combining the combiner 40 with a light control material, the combiner 40 may also serve as a light control member instead of the dustproof cover 21.

  (3c) A plurality of functions of one constituent element in the above embodiment may be realized by a plurality of constituent elements, or a single function of one constituent element may be realized by a plurality of constituent elements. . Further, a plurality of functions possessed by a plurality of constituent elements may be realized by one constituent element, or one function realized by a plurality of constituent elements may be realized by one constituent element. Moreover, you may abbreviate | omit a part of structure of the said embodiment. In addition, at least a part of the configuration of the above embodiment may be added to or replaced with the configuration of the other embodiment. In addition, all the aspects included in the technical idea specified from the wording described in the claims are embodiments of the present disclosure.

  (3c) In addition to the head-up display device described above, the present disclosure can also be realized in various forms such as a system including the head-up display device as a constituent element and a method for suppressing external light incident on the head-up display device. .

  DESCRIPTION OF SYMBOLS 1 ... Head-up display apparatus, 10 ... Optical unit, 11 ... Display, 12 ... Plane mirror, 13 ... Concave mirror, 14 ... Illuminance sensor, 15 ... Temperature sensor, 16 ... Backlight control part, 20 ... Housing | casing, 20a ... Opening Part, 21 ... dust-proof cover, 30 ... windshield, 31 ... intermediate film, 40 ... combiner, 111 ... liquid crystal panel, 112 ... backlight light source, ER ... eye range.

Claims (6)

A display (11) that emits visible light, and an optical component (12, 13) that guides display light output from the display to a projection member (30, 40) provided in front of a vehicle driver; An optical unit (10) configured to generate a virtual image display to be visually recognized by the driver by reflecting the display light on the projection target member;
A housing (20) configured to house the optical unit;
A dimming member (provided in the optical path from the display to the projection member, and configured such that the light transmittance decreases as the amount of activation light, which is light having a preset wavelength, increases) 21) and
A head-up display device. The head-up display device according to claim 1,
A head-up display device, wherein the light control member is configured to change at least infrared transmittance. The head-up display device according to claim 1 or 2,
The light control member is configured to include at least visible light as the activation light. The head-up display device according to any one of claims 1 to 3,
A dust-proof cover that covers an opening of the housing formed to allow the display light to pass through;
A head-up display device configured such that the dust cover also serves as the light control member. The head-up display device according to any one of claims 1 to 3,
A combiner (40) as the projection member;
A head-up display device configured such that the combiner also serves as the light control member. The head-up display device according to any one of claims 1 to 5,
A sensor unit (14) for acquiring information related to the transmittance of the light control member;
A display adjustment unit (16) that changes the amount of the display light output from the display unit according to the transmittance of the light control member estimated from the output of the sensor unit;
Further comprising
Head-up display device.

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