JP6664555B2 - Head-up display device - Google Patents

Description

  The present invention relates to a head that reflects display light of an image displayed on an image display surface to an observer side on an image reflection surface facing an observer, and enlarges and displays an image as a virtual image over the image reflection surface to the observer. The present invention relates to an up display device.

  2. Description of the Related Art Conventionally, a head-up display device has been known as a device that displays information such as a direction instruction, a warning, and a traveling speed for a driver of an automobile or the like. The head-up display device projects a virtual image of an image to be displayed on an image reflecting surface such as a front window or a combiner so that a driver can recognize information necessary for driving an automobile or the like without looking away from the field of view. It is to make. Patent Documents 1 to 5 have been proposed as such a head-up display device.

Patent No. 6096911 JP 2014-170112 A JP 2016-186509 A JP-A-2006-95411 JP-A-2006-224461

  Since such a head-up display device must be installed in a limited space around the driver's seat of a moving body such as an automobile, it is required to be small.

  In recent head-up display devices, a method called Augmented Reality (AR) has been proposed in which navigation information and / or facility information is displayed in accordance with a scene seen through a front window. When displaying this AR content, it is not effective unless the information is displayed exactly in accordance with the location of each facility and / or road in the scenery seen through the front window, so that the position of the driver's eyes is considered. Thus, it is necessary to set the virtual image display position and angle strictly.

  By the way, in the head-up display device, a range in which a driver can appropriately observe a virtual image, that is, an eye box is determined. This eye box is set in a range in which the driver's eyes are expected to be located when the driver takes an appropriate driving posture. Since the position of the driver's seat in the left-right direction is generally fixed, it is unlikely that the driver's eyes separate from the eyebox in the left-right direction. However, the position of the driver's seat in the front-rear direction and the vertical direction is generally adjustable, and the driver's height and driving posture are also various, so that the driver's eyes are displaced from the eye box in the vertical direction. It will be easier.

  In order to solve such a problem, it is conceivable that the display unit of the head-up display device is rotated in the front-rear direction of the vehicle in accordance with the driver's pupil position, so that the vertical position of the eye box can be adjusted. However, in this case, since the display depression angle of the virtual image changes, it is not suitable for displaying AR-based content.

  From the above, there is a demand for a head-up display device that is small in size but expands the eyebox itself in the vertical direction and can appropriately display virtual images to various drivers. In this device, a head-up display device in which the optical path is bent using two or three mirrors has not been sufficiently miniaturized. Further, the apparatuses disclosed in Patent Documents 4 and 5 have a problem that the vertical direction of the eye box is as narrow as about 60 mm (millimeter).

  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 that is small and has a wide range in the vertical direction of an eye box.

  The head-up display device of the present invention reflects the display light of the image displayed on the image display surface to the observer side on the image reflection surface facing the observer, and forms a virtual image on the observer through the image reflection surface. A head-up display device that enlarges and displays the image as an image display surface, a first concave mirror, a second concave mirror, and a third concave mirror, wherein display light emitted from the image display surface is The first concave mirror, the second concave mirror, and the third concave mirror reflect in this order, reach the image reflecting surface, and an intermediate image of the image displayed on the image display surface between the second concave mirror and the third concave mirror. Is formed, and the light beam traveling from the image display surface to the first concave mirror intersects with the light beam traveling from the second concave mirror to the third concave mirror.

  Here, the “image display surface” means not only the image display surface of the image display element itself, but also the range of the pupil position of the observer who can properly observe the virtual image (hereinafter, referred to as an eye box). Regarding an image displayed on the image display element that is once projected onto a diffusion member such as a diffuser, the image display surface of the diffusion member may be regarded as the above-mentioned “image display surface”.

In the head-up display device of the present invention, the reflection area of the display light on the first concave mirror is M1, the reflection area of the display light on the second concave mirror is M2, and the reflection area of the display light on the third concave mirror is M3. In this case, it is preferable to satisfy the conditional expression (1).
M2 <M1 <M3 (1)

  Here, the “reflection area of the display light on the first to third concave mirrors” is not the area of the reflection surface of each concave mirror, but contributes to the reflection of the display light in the reflection surface of each concave mirror. Means the area of

  Further, it is preferable that the image display surface is disposed on the side opposite to the image reflection surface with respect to the light beam traveling from the second concave mirror to the third concave mirror.

  Further, it is preferable that a stop is provided between the second concave mirror and the third concave mirror.

  The head-up display device of the present invention reflects the display light of the image displayed on the image display surface to the observer side on the image reflection surface facing the observer, and forms a virtual image on the observer through the image reflection surface. A head-up display device for enlarging and displaying an image as an image, having an image display surface, a first concave mirror, a second concave mirror, and a third concave mirror, wherein display light emitted from the image display surface is The first concave mirror, the second concave mirror, and the third concave mirror reflect in this order, reach the image reflecting surface, and an intermediate image of the image displayed on the image display surface between the second concave mirror and the third concave mirror. Is formed, and the luminous flux going from the image display surface to the first concave mirror and the luminous flux going from the second concave mirror to the third concave mirror intersect with each other, so that the vertical range of the eye box is small. Wide head Can be-up display device.

FIG. 1 is a schematic view of a driver seat of an automobile equipped with a head-up display device according to an embodiment of the present invention. Schematic configuration diagram of the head-up display device 1 is a schematic configuration diagram of a head-up display device according to an embodiment of the present invention. Sectional view of light flux on aperture (aperture) surface of head-up display device of the above embodiment

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram of a driver's seat of an automobile equipped with a head-up display device according to an embodiment of the present invention, and FIG. 2 is a schematic configuration diagram of the head-up display device.

  As shown in FIG. 1, a head-up display device 10 of the present embodiment is arranged in a dashboard of an automobile, and displays an image indicating information such as a traveling speed emitted from the inside of the device on a front window (image reflection surface) 6. The reflected light is enlarged and displayed as a virtual image 8 in front of the driver (observer) 7 through the front window 6.

  As shown in FIG. 2, the head-up display device 10 has an image display surface 1, a first concave mirror 2, a second concave mirror 3, and a third concave mirror 5, and emits light from the image display surface 1. The displayed light is reflected in the order of the first concave mirror 2, the second concave mirror 3, and the third concave mirror 5, and reaches the image reflection surface.

  The image display surface 1 may be configured such that the image display surface of an image display element such as an LCD (Liquid Crystal Display) or an OLED (Organic Light Emitting Diode) is the image display surface 1 in FIG. A configuration may be adopted in which a screen is arranged on the display surface 1 and an image is projected on the screen using a projector device (not shown).

  In addition, the three mirrors (the first concave mirror 2, the second concave mirror 3, and the third concave mirror 5) for bending the light beam are all concave mirrors, so that the power for converging the light beam is three. Can be shared by the mirrors, so that aberrations can be suppressed.

  Further, an intermediate image of the image displayed on the image display surface 1 is formed between the second concave mirror 3 and the third concave mirror 5. With such a configuration, the luminous flux around the intermediate image can be reduced while the eye box is enlarged, so that the entire apparatus can be reduced in size.

  Further, the light beam traveling from the image display surface 1 to the first concave mirror 2 and the light beam traveling from the second concave mirror 3 to the third concave mirror 5 intersect. With such a configuration, it is possible to reduce the size of the entire device while securing the optical path length.

  From the above, the head-up display device 10 of the present embodiment can be a small-sized head-up display device having a wide range in the vertical direction of the eye box while suppressing aberration.

In the head-up display device 10 of the present embodiment, the reflection area of the display light on the first concave mirror 2 is M1, the reflection area of the display light on the second concave mirror 3 is M2, and the reflection of the display light on the third concave mirror 5 is M1. When the area is M3, it is preferable to satisfy the conditional expression (1). With such a configuration, the display light emitted from the image display surface 1 is converged by the first concave mirror 2, and the light flux of the display light between the first concave mirror 2 and the intermediate image is relatively narrow. The second concave mirror 3 is disposed on the second mirror, and the third concave mirror 5 converges the luminous flux of the display light diverged from the intermediate image again. The image of the pupil of the driver (observer) 7 and the second concave mirror Since the lenses 3 are close to each other and have an arrangement suitable for correcting spherical aberration, the second concave mirror 3 can effectively correct spherical aberration.
M2 <M1 <M3 (1)

  Further, it is preferable that the image display surface 1 is disposed on the side opposite to the image reflection surface 6 with respect to the light beam traveling from the second concave mirror 3 to the third concave mirror 5. With such a configuration, it is easy to secure a space for arranging the members constituting the image display surface 1.

  Further, it is preferable that the diaphragm 4 is provided between the second concave mirror 3 and the third concave mirror 5. With such a configuration, stray light can be prevented, and the display contrast of the virtual image 8 can be improved.

  Next, numerical examples of the head-up display device of the present invention will be described. FIG. 3 is a schematic configuration diagram of the head-up display device according to the embodiment, and FIG. 4 is a sectional view of a light beam on a stop (opening) surface of the head-up display device according to the embodiment. FIG. 2 includes the contents as a configuration diagram for explaining the configuration of the embodiment.

  Table 1 shows the data on the specifications. Here, FOV (Field of View) [horizontal direction H × vertical direction V] (°), eye box (entrance pupil) size (horizontal direction (mm: millimeter)) × vertical direction (mm: millimeter)), virtual image distance (Mm: millimeter) and the value of the image display area (horizontal direction (mm: millimeter) × vertical direction (mm: millimeter)).

  Table 2 shows arrangement coordinate data of each element constituting the head-up display device. Here, an absolute coordinate system whose origin is the center of the image display surface 1 shown in FIG. 2, a first concave mirror 2, a second concave mirror 3, an aperture (aperture) 4, a third concave mirror 5, and an image reflecting surface 6, a viewer (indicated as a pupil in Table 2) 7, and a local coordinate system set on the surface of each element of the virtual image 8 are described in combination.

  The setting of the local coordinate system is as follows. Let the origin of each local coordinate system and the component vector of the Z axis be (x, y, z) and (i, j, k) in the absolute coordinate system, respectively. A plane (XY plane) passing through the origin of each local coordinate system and orthogonal to the Z axis is used as a reference plane of each element, and the normal vector N of each reference plane matches the Z axis of the local coordinate system. The X axis is orthogonal to the display surface in FIG. 2, and the near side of the display surface is the plus side. The Y axis and the Z axis are parallel to the display surface in FIG. Further, the Y axis is set so as to coincide with the cross product of the Z axis and the X axis. The reference surfaces of the first concave mirror 2, the second concave mirror 3, the third concave mirror 5, and the image reflecting surface 6 have a paraxial curvature, and a free-form surface is set as an additional shape thereon. In the element having an aperture value, a rectangular aperture having a long side on the X axis and a short side on the Y axis is set on the reference plane.

  The first concave mirror 2, the second concave mirror 3, the third concave mirror 5, and the image reflecting surface 6 are reflecting surfaces having power. Table 3 shows data relating to the free-form surface coefficient of each surface. The free-form surface coefficient is a value of a rotationally asymmetric aspherical surface coefficient C (i, j) in the free-form surface expression represented by the following expression. Note that a rotationally asymmetric aspheric coefficient not particularly described in Table 3 is 0.

However,
X, Y, Z: coordinates at the origin of the surface vertex C (i, j): rotationally asymmetric aspherical coefficient (i + j = k, k = 1 to 10)
And

  From the above data, the vertical range of the eye box of the head-up display device of the embodiment is 150 mm, which is wider and smaller than a general head-up display device, and the vertical range of the eye box is wider. It can be seen that this is a head-up display device.

  As described above, the present invention has been described with reference to the embodiment and the example. However, the present invention is not limited to the embodiment and the example, and various modifications are possible. For example, the position and size of each element constituting the head-up display device are not limited to the values shown in the above-described numerical embodiments, but may take other values.

Claims (4)

A head for reflecting display light of an image displayed on an image display surface on an image reflection surface facing an observer to the observer side, and enlarging and displaying the image as a virtual image over the image reflection surface to the observer. An up display device,
The image display surface, a first concave mirror, a second concave mirror, and a third concave mirror,
The display light emitted from the image display surface is reflected in the order of the first concave mirror, the second concave mirror, and the third concave mirror to reach the image reflection surface,
Forming an intermediate image of the image displayed on the image display surface between the second concave mirror and the third concave mirror;
A head-up display device in which a light beam traveling from the image display surface to the first concave mirror and a light beam traveling from the second concave mirror to the third concave mirror intersect. The reflection area of the display light on the first concave mirror is M1,
The reflection area of the display light on the second concave mirror is M2,
When the reflection area of the display light on the third concave mirror is M3,
M2 <M1 <M3 (1)
The head-up display device according to claim 1, wherein conditional expression (1) represented by the following expression is satisfied. The head-up display device according to claim 1, wherein the image display surface is disposed on a side opposite to the image reflection surface with respect to a light beam traveling from the second concave mirror to the third concave mirror. The head-up display device according to any one of claims 1 to 3, further comprising a stop between the second concave mirror and the third concave mirror.