JPH07101267A - Head up display device - Google Patents

Abstract

PURPOSE:To provide a head up display device making a display image visible not only to a driver but also to occupants in an assistant's seat and a rear seat. CONSTITUTION:This head up display device is provided with a display 2 for displaying a display image, and a hologram 3 formed by recording a concave mirror 14 reflecting display light radiated from the display 2. A display image is reflected on the inside of a windshield 5 and focused in front of the outside of the windshield. The hologram 3 is manufactured through multiple exposure by changing the angle of the concave mirror 14 to a hologram dry plate 3a at the time of exposure so that the display light from the display 2 is diffracted and reflected in plural directions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automobile head-up display device using a hologram.

[0002]

2. Description of the Related Art As a device for displaying a meter or the like of an instrument panel of an automobile, an image of the meter or the like is projected on a windshield, and an image reflected by the windshield is made incident on a driver's eye, so that the windshield A head-up display device is known in which the image is formed on the front outside so that a driver can visually recognize a meter or the like without looking away.

As a head-up display device of this type, a hologram that reflects only light in the wavelength region that is incident at a specific angle is arranged in a part of the optical system, and the display image reflected by the hologram is displayed on the inner surface of the windshield or its inside. With a combiner attached inside, reflect in the driver's line of sight,
Devices have been developed that reduce the influence of external light such as sunlight.

[0004]

By the way, in this type of head-up display device, the hologram emits the display light from the display device at a specific emission angle, and the display light is displayed to the eyes of the driver located at a specific location. To make the incident.
Therefore, there is a problem that passengers in the front passenger seat and the rear seat, which the display light does not reach, cannot see the display on the head-up display.

The present invention has been made in view of the above points, and an object of the present invention is to provide a head-up display device in which a driver and a passenger in a passenger seat or a rear seat can visually recognize a displayed image. To do.

[0006]

In order to achieve the above object, a head-up display device of the present invention comprises a display for displaying a display image and a hologram for reflecting display light emitted from the display. In a head-up display device that has a display image reflected on the inside of the windshield and an image is formed on the outside of the windshield, the hologram is designed so that the display light from the display is diffracted and reflected in a plurality of different directions. In addition, at the time of exposure, it is manufactured by multiple exposure by changing the angle with respect to the hologram dry plate.

[0007]

In the head-up display device configured as described above, multiple exposure is performed by changing the angle with respect to the hologram plate during exposure so that the display light from the display is diffracted and reflected in a plurality of different directions. Then, the hologram is produced, and if the hologram is subjected to multiple exposure so that the display light from the display is directed to the driver, the passenger seat or / and the passenger in the rear seat, the hologram is reflected by the windshield or the like. The display light is reflected not only to the driver but also to the passenger and / or the rear seat occupant, and not only the driver,
An occupant in the passenger seat and / or the rear seat can also visually recognize the display on the head-up display.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in the schematic block diagram of FIG. 1, the head-up display device is mainly composed of a display 2 and a hologram 3, and the display 2 is a liquid crystal display with a backlight, an EL display, It consists of a CRT, etc., and is installed inside the dashboard of a car.
Displays warning images, etc.

In front of the display device 2, a hologram 3 is arranged so as to be inclined at a position for receiving the display light emitted from the display device 2. The hologram 3 diffracts / reflects the display light, and the light travels upward, is reflected inside the windshield 5 located above, and enters the eyes of the driver and the passenger in the passenger seat or the rear seat. The angle and position of the hologram 3 etc. are set.

A vapor-deposited film of titanium oxide or the like is attached as a semi-transmissive reflective film on the inside of the windshield 5 serving as a combiner, but a reflective surface is formed on the glass surface without attaching the vapor-deposited film. You may

The hologram 3 used here has a light reflection characteristic of diffracting / reflecting only the light of the specific wavelength at the specific emission angle by exposing the light of the specific wavelength at the specific incident angle. Both are exposed to record a concave mirror (eg, off-axis parabolic mirror) 14 therein. Also,
By changing the position of the concave mirror, that is, changing the incident angle of light to perform multiple exposure, the display light from the display 2 is diffracted and reflected not only by the driver but also by the passenger in the passenger seat or the rear seat. It is manufactured as follows.

That is, the hologram 3 is exposed and manufactured by using an optical system as shown in FIGS. FIG. 2 shows a side sectional view, and FIG. 3 shows a plane sectional view.
Reference numeral 3a denotes a hologram dry plate, which is formed by depositing dichromated gelatin serving as a photosensitizer to a thickness of about 20 nm on a base material such as soda glass and drying it. In addition to dichromated gelatin, silver salts, photopolymers, sensitizers such as elepon can also be used.

As shown in FIG. 2, on both sides of the hologram dry plate 3a, glass 11 with an antireflection film is sandwiched and adhered via a refractive index adjusting liquid 10, and the hologram dry plate 3a in such a state is It is arranged in a part of the optical system so as to be exposed by parallel light and divergent light of the same wavelength from both sides.

For example, a laser beam having a wavelength of 514.5 μm is used as a light source, and the laser beam emitted from a laser oscillator (not shown) passes through a lens 12 for divergence and is incident on one side of the hologram dry plate 3a as divergent light. The optical system is arranged as described above. On the other side of the hologram 3a, a concave mirror (off-axis paraboloidal mirror) 14 is arranged diagonally forward, and a part of the laser light emitted from the same laser oscillator irradiates the concave mirror 14 through the lens 13. Then, the parallel light reflected by the concave mirror 14 enters the hologram dry plate 3a.

At the time of exposure, the hologram dry plate 3 of the concave mirror 14
The angle with respect to a (the angle in the left-right direction in plan view) is shown in FIG.
As shown by the phantom line, the multiple exposure is performed by changing the angle α to the angle β. When the exposed and manufactured hologram is arranged and used as shown in FIG. 1, the display light reflected and diffracted by the hologram and reflected by the windshield 5 is used as the angle α and the angle β. It is decided to reach the eyes of the passenger or passenger in the back seat.

Further, as shown in FIG. 2, the incident angle θ (incident angle in the vertical direction in a side view) between the diverging light and the parallel light on the hologram dry plate 3a is actually the hologram 3 as a head-up display. In order to match the reproduction angle when used, for example, θ = 33.5 ° is set.

When performing the exposure, first, the concave mirror 14 is arranged at the position shown by the solid line in FIG. 3, the angle with respect to the hologram dry plate 3a is α, and the laser light of a predetermined wavelength is reflected by the lens 13.
Through the concave mirror 14 and the parallel light reflected from the concave mirror 14 is made incident on the hologram dry plate 3a. At the same time, the same laser light is made to diverge by the lens 12 and made to enter the hologram dry plate 3a from the opposite side. Exposure.

Next, the concave mirror 14 is moved to the position of the imaginary line in FIG. 3, and the angle with respect to the hologram dry plate 3a is β,
Similarly, the parallel light reflected from the concave mirror 14 is made incident on the hologram dry plate 3a, and the divergent light from the lens 12 is made incident on the hologram dry plate 3a from the opposite side to perform the next exposure.

In this way, the angle of the concave mirror 14 is changed to 2
After multiple times of multiple exposure, a predetermined developing / fixing process is performed to manufacture the hologram 3, and two concave mirrors 14 and 14 arranged at different angles are recorded on the hologram 3 as interference fringes.

When performing the first exposure and the second exposure, by changing the incident angle θ of the parallel light and the divergent light to a predetermined angle, the display light diffracted / reflected from the hologram at the time of use is changed. It is also possible to change the wavelength or color depending on the viewing direction.

In the hologram 3 thus manufactured, in order to prevent scattering and reflection on the surface and to prevent deterioration of the hologram layer, a cover plate made of epoxy resin is adhered in a sandwich form from the front and back through a sealant. The anti-reflection film and the anti-scattering film are formed on the surfaces of the front and back cover plates to complete the process. Then, as shown in FIG. 4, the hologram 3 is arranged below the windshield 5 at a predetermined angle θ (33.5 °) with respect to the optical axis of the display 2.

In the head-up display device configured as described above, as shown in FIG. 4 and FIG. 5 showing its plane, the light of the velocity image and the warning image emitted from the display 2 is incident on the hologram 3. The light of the specific wavelength diffracted and reflected by the hologram 3 travels upward.

At this time, since the two concave mirrors 14 whose angles are changed to α and β are recorded in the hologram 3 by multiple exposure, the display light diffracted / reflected from the hologram 3 as shown in FIG. Is an angle α1 corresponding to the angle α during exposure (angle with respect to the hologram plane) and an angle β1 corresponding to the angle β during exposure (angle with respect to the hologram plane)
Is emitted at. Then, one display light is reflected inside the windshield 5 and is incident on the eyes of the driver, and the other display light is reflected inside the windshield 5 and the eyes of the passenger or the passenger in the rear seat. Incident on.

Therefore, as shown in FIG. 1, for the eyes of the driver and the passenger or passenger in the rear seat, the speed image displayed on the display 2 is an image projected in front of the windshield 5. To be seen.

At this time, as shown in FIG. 4, the focal point F of the concave mirror recorded on the hologram 3 is located at the rear part of the display 2, and the focal length f thereof is the distance a between the display 2 and the hologram 3.
Since the virtual image B of the display image is generated on the back side of the hologram 3 and the distance b between the virtual image B and the hologram 3 is longer than the distance a, the magnification ratio m (m = b / a) of the display image exceeds 1. , An enlarged image is displayed.

According to a trial experiment, when the focal length of the concave mirror recorded on the hologram is 978 mm, the distance a between the display and the hologram is 400 mm, and the distance between the hologram and the windshield is 142 mm, the front of the windshield is A display image was displayed at a position of about 1000 mm.

Although the hologram 3 is arranged below the windshield 5 in the above description, the hologram 3 may be enclosed inside the windshield 5 or attached inside the windshield 5 as shown in FIG. it can.

The display 2 is usually installed inside the dashboard as shown in FIG. 6, but as shown in FIG. 7, the display 21 and the reflector 2 are provided in an independent case 20.
Alternatively, the head-up display device can be configured by disposing the two and mounting the hologram 23 on the upper part of the case 20 at a predetermined angle. This device is used by being placed at an arbitrary position on the dashboard so that the light diffracted / reflected from the hologram 23 enters the eyes of the driver or the like.

In the above embodiment, the concave mirrors with two different angles are recorded on the hologram by two multiple exposures, but the concave mirrors with three different angles are recorded on the hologram by three multiple exposures. The display light can be diffracted / reflected in three directions so that the driver, the passenger in the passenger seat, and the passenger in the rear seat can see the displayed image.
Also, instead of the concave mirror, a plane mirror can be recorded in the hologram.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional configuration diagram of a head-up display device showing an embodiment of the present invention.

FIG. 2 is a side sectional view showing an optical system when a hologram 3 is exposed.

FIG. 3 is a cross-sectional view from the plane side during the same exposure.

FIG. 4 is a side view showing a display 2, a hologram 3, a windshield 5, and an optical path therebetween.

5 is a plan arrow diagram of line VV in FIG. 4. FIG.

FIG. 6 is a schematic sectional view of a head-up display device showing another embodiment.

FIG. 7 is a perspective view of a head-up display device showing still another embodiment.

[Explanation of symbols]

 2-Display, 3-Hologram, 3a-Hologram dry plate, 5-Front glass, 14-Concave mirror.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhiro Mizutani 1-1, Showa-cho, Kariya city, Aichi Prefecture Nihondenso Co., Ltd.

Claims (3)

[Claims] 1. A display device for displaying a display image, and a hologram for reflecting display light emitted from the display device, wherein the display image is reflected on the inside of the windshield and the display image is formed on the outside front side thereof. In a head-up display device for forming an image, the hologram is produced by multiple exposure by changing an angle with respect to a hologram dry plate at the time of exposure so that display light from a display is diffracted and reflected in a plurality of different directions. Head-up display device characterized by being. 2. The head-up display device according to claim 1, wherein a concave mirror is recorded on the hologram. 3. The head-up display device according to claim 1, wherein the hologram is subjected to multiple exposure by changing an angle with respect to the hologram dry plate so that lights having different wavelengths are diffracted and reflected in different directions.