JP7040094B2 - Head-up display device - Google Patents

Description

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

A head-up that displays information superimposed on the background beyond the driver's line of sight by reflecting the display light output via the liquid crystal display on the vehicle's windshield and forming a virtual image in the front view of the vehicle driver. 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 incident on the HUD through the windshield, and the display performance deteriorates.
The following Patent Document 1 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.

Japanese Unexamined Patent Publication No. 2017-15778

However, as a result of detailed studies by the inventor, the following problems have been found in the prior art described in Patent Document 1.
That is, in the prior art, the component of the external light that passes through the polarizing plate cannot be prevented from entering the HUD device, so that a sufficient temperature suppressing effect cannot be obtained. Therefore, it is necessary to use a combination of derating control that suppresses the current flowing through the backlight light source of the liquid crystal display before the allowable temperature of the liquid crystal display is exceeded, and light source off control that turns off the current flowing through the backlight light source. 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.

The head-up display device according to one aspect of the present disclosure includes an optical unit (10), a housing (20), and a dimming member (21).
The optical unit has a display (11) that emits visible light and an optical component (12, 13) that guides the display light output from the display to a projected member (30, 40) provided in front of the driver of the vehicle. By having and reflecting the display light by the projected member, a virtual image display to be visually recognized by the driver is generated. The housing houses the optical unit. The dimming member is provided in the optical path from the display to the projected member, and the larger the amount of activated light, which is light having a preset wavelength, the lower the transmittance of light.

According to such a configuration, the larger the amount of activated light, the lower the transmittance of the light, and the less the external light reaching the display can be reduced. As a result, it is possible to suppress heat generation of the display based on external light, and eventually deterioration of 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.

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

It is a block diagram which shows the structure and operation of the head-up display apparatus of 1st Embodiment. It is explanatory drawing which shows the action of the head-up display device with respect to the outside 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 a display | display in 3rd Embodiment.

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

The windshield 30 has a built-in interlayer film 31 having a wedge-shaped cross-sectional shape. The interlayer film 31 has a function of controlling the refraction of light by utilizing its cross-sectional shape so that a virtual image based on the display light reflected by the windshield 30 is clearly reflected. Further, the interlayer film 31 may have a heat shielding function of blocking 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. Housing]
The housing 20 is a box-shaped object having a space for accommodating the optical unit 10. The housing 20 has an opening 20a on the upper surface facing the windshield 30 in a state of being attached to the dashboard for extracting the display light output from the optical unit 10 to the outside. A dustproof cover 21 made of a material that transmits display light is attached to the opening 20a.

The dustproof cover 21 is a material containing a photochromic compound that becomes darker as the amount of light increases and at least lowers the transmittance of infrared rays, depending on the amount of activated light which is light having a preset wavelength (hereinafter, It is formed by using a dimming member). In this embodiment, a photochromic compound containing at least visible light is used as the activation light. As a photochromic lens containing a photochromic compound having such a function, for example, transition extraactive 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 11 includes a liquid crystal panel 111 and a backlight light source 112. As the liquid crystal panel 111, a TFT liquid crystal display having a large number of thin film-like fine transistors arranged for turning on and off pixels on a glass substrate is used. TFT is an abbreviation for Thin Film Transistor. The backlight light source 112 is a light source that generates a backlight that illuminates the liquid crystal panel from the back surface. The light emitted from the backlight light source 112 and passing through the liquid crystal panel 111 is output as display light. A light emitting diode is used for the backlight light source 112, but the backlight source 112 is not limited to this.

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 magnifying a 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. motion]
As shown by the broken line in FIG. 1, the display light projected from the HUD device 1 through the dustproof cover 21 is reflected by the windshield 30 and directed to the driver's line of sight, that is, the eye range ER. As a result, 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 range of distribution that statistically indicates the position of the driver's eyes.

Here, as shown in FIG. 2, external light such as sunlight passing through the windshield 30 and heading toward the dustproof cover 21 passes through the dustproof cover 21, is reflected by the concave mirror 13 and the plane mirror 12, and reaches the display 11. do. The external light that reaches the display 11 becomes a factor that heats 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 toward the eye range ER. Hereinafter, this light is referred to as external light reflected light. The reflected external 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 dustproof cover 21 is made of a dimming material, the amount of external light is attenuated when it is incident into the housing 20 through the dustproof 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 via the dustproof cover 21. That is, since the external light reflected light passes through the dustproof cover 21 made of the dimming 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 the present embodiment, since the dustproof cover 21 is made of a dimming material, it is possible to suppress the incident amount of external light incident on the inside of the HUD device 1. As a result, not only the heat generation of the display 11 due to external light and the deterioration of the display performance due to the heat generation can be suppressed, but also the derating control and the light source off control of the backlight light source 112 can be omitted.

(1b) In the present embodiment, since the dimming material forming the dustproof cover 21 contains visible light in the activated light, even in an environment where a windshield 30 that blocks ultraviolet rays is used, light is emitted according to the amount of visible light. The transmittance of the light can be changed.

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

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

In the first embodiment described above, the backlight light source 112 emits light with a constant amount of light. 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 conditions.

[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, among the configurations shown in the first embodiment, configurations other than the display 11 are omitted. Further, the illuminance sensor 14 corresponds to the sensor unit, and the backlight control unit 16 corresponds to the display adjustment unit.

The illuminance sensor 14 is a sensor that measures the intensity of external light incident on the dustproof cover 21. The illuminance sensor 14 is installed, for example, outside the housing 20 and near the dustproof 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 amount of light of the backlight light source 112 according to the transmittance of the dustproof cover 21 formed of the dimming member estimated from the intensity of the illuminance sensor 14. Specifically, as the estimated transmittance decreases, the amount of light of the backlight light source 112 is increased so as to compensate for the amount of light that is reduced when the display light passes through the dustproof cover 21. The backlight control unit 16 may control the amount of light of the backlight light source 112 to increase the amount of light only when the temperature measured by the temperature sensor 15 is within a preset allowable range. ..

[2-3. effect]
According to the second embodiment described in detail above, the effect (1a) of the above-mentioned first embodiment is achieved, and the following effects are further achieved.

(2a) By reducing the transmittance of the dustproof cover 21 formed of the dimming member, it is possible to suppress the deterioration of the appearance of the virtual image based on the display light.
[3. Other embodiments]
Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and can be variously modified and implemented.

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

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

(3c) A plurality of functions possessed by one component in the above embodiment may be realized by a plurality of components, or one function possessed by one component may be realized by a plurality of components. .. Further, a plurality of functions possessed by the plurality of components may be realized by one component, or one function realized by the plurality of components may be realized by one component. Further, a part of the configuration of the above embodiment may be omitted. Further, at least a part of the configuration of the above embodiment may be added or replaced with the configuration of the other above embodiment. It should be noted that all 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 above-mentioned head-up display device, the present disclosure can be realized in various forms such as a system having the head-up display device as a component and a method of suppressing external light incident on the head-up display device. ..

1 ... Head-up display device, 10 ... Optical unit, 11 ... Display, 12 ... Plan mirror, 13 ... Concave mirror, 14 ... Illuminance sensor, 15 ... Temperature sensor, 16 ... Backlight control unit, 20 ... Housing, 20a ... Opening Part, 21 ... Dustproof cover, 30 ... Windshield, 31 ... Intermediate film, 40 ... Combiner, 111 ... Liquid crystal panel, 112 ... Backlight light source, ER ... Eye range.

Claims (5)

It has an indicator (11) that emits visible light and an optical component (12,13) that guides the indicator light output from the indicator to a projected member (30, 40) provided in front of the driver of the vehicle. An optical unit (10) configured to generate a virtual image display to be visually recognized by the driver by reflecting the display light by the projected member.
A housing (20) configured to house the optical unit and
A dimming member provided in the optical path from the display to the projected member so that the light transmittance decreases as the amount of activated light, which is light having a preset wavelength, increases. 21) and
A dustproof cover that covers the opening of the housing formed to allow the display light to pass through, and a dustproof cover.
Equipped with
The dustproof cover is configured to also serve as the dimming member.
Head-up display device. It has an indicator (11) that emits visible light and an optical component (12,13) that guides the indicator light output from the indicator to a projected member (30, 40) provided in front of the driver of the vehicle. An optical unit (10) configured to generate a virtual image display to be visually recognized by the driver by reflecting the display light by the projected member.
A housing (20) configured to house the optical unit and
A dimming member provided in the optical path from the display to the projected member so that the light transmittance decreases as the amount of activated light, which is light having a preset wavelength, increases. 21) and
A sensor unit (14) that acquires information related to the transmittance of the dimming member, and
A display adjusting unit (16) that changes the amount of the display light output from the display according to the transmittance of the dimming member estimated from the output of the sensor unit.
A head-up display device. The head-up display device according to claim 2 .
A combiner (40) as the projected member is provided.
A head-up display device configured such that the combiner also serves as the dimming member. The head-up display device according to any one of claims 1 to 3 .
The dimming member is a head-up display device configured to change at least the transmittance of infrared rays. The head-up display device according to any one of claims 1 to 4 .
The dimming member is a head-up display device configured to include at least visible light as the activation light.

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