KR102695520B1 - Image display device - Google Patents

Abstract

An image display device is provided, comprising: a scanning optical section for scanning laser light; a beam shaper on which the laser light scanned by the scanning optical section is incident approximately vertically; two reflective optical elements having free-form surfaces; and one anamorphic lens; an illumination optical section for illuminating a display panel with the laser light emitted from the beam shaper; the display panel for displaying an image using the laser light illuminated from the illumination optical section; and an eyepiece optical section including three reflective optical elements having free-form surfaces and focusing the image light emitted from the display panel onto the eyes of an observer.

Description

IMAGE DISPLAY DEVICE

Hereinafter, a technology relating to an image display device is provided.

A head-up display device can create augmented reality (AR) by superimposing a virtual image on a real scene in front of a vehicle, thereby adding information to the real scene. The head-up display device can contribute to safe and comfortable driving by providing desired information to an observer accurately while minimizing eye movement of the observer driving the vehicle.

Japanese Patent Publication No. 2016-014861

An image display device according to one embodiment may include: a scanning optical unit that scans laser light; a beam shaper on which laser light scanned from the scanning optical unit is vertically incident; an illumination optical unit that includes two reflective optical elements having free-form curves and one anamorphic lens and illuminates a display panel with the laser light emitted from the beam shaper; the display panel that displays an image using the laser light illuminated from the illumination optical unit; and an eyepiece optical unit that includes three reflective optical elements having free-form curves and focuses image light emitted from the display panel onto the eyes of a viewer.

The image display device may further include a first control unit that controls a position at which the injected laser light is incident on the beam shaper based on the position information of the eye.

The above-mentioned scanning optical unit includes a laser scanning unit, and the first control unit can control the position at which the injected laser light is incident on the beam shaper by controlling the laser scanning unit.

The above first control unit can focus the image light by controlling the position at which the injected laser light is incident on the beam shaper in response to a change in position in the direction perpendicular to the optical axis of the eye.

The image display device may further include a second control unit that controls the position of the beam shaper based on the position information of the eye.

The above second control unit can control the position of the beam shaper forward and backward with respect to the optical axis.

The second control unit can focus the image light by controlling the position of the beam shaper in response to the eye moving back and forth with respect to the optical axis.

The above beam shaper may be a diffractive optics element (DOE), a holographic optical element (HOE), or a diffuser plate.

The image display device may further include a third control unit that controls the content of the image based on the position information of the eye.

The third control unit can provide right-eye images and left-eye images that are distinct from each other for both eyes.

The above scanning optical unit may further include a light source unit that emits the laser light; a laser scanning unit that scans the laser light emitted from the light source unit; and a mirror that reflects the laser light scanned by the laser scanning unit and causes the laser light to enter the beam shaper.

The above laser injection unit may be implemented as a MEMS (Micro Electro Mechanical Systems) scanner, and the mirror may be implemented as a parabolic mirror.

The light source unit may include a condensing lens that concentrates the laser light onto a diffuser; the diffuser plate that scatters the laser light concentrated by the condensing lens; a collimating lens that emits parallel light generated by collimating the laser light scattered by the diffuser plate to the laser scanning unit; and a motor that rotates the diffuser plate.

The above-described eyepiece optical unit may include a front end free-form mirror that reflects image light emitted from the display panel; a back end free-form mirror that additionally reflects image light reflected by the front end free-form mirror; and a combiner that additionally reflects image light reflected by the back end free-form mirror to focus the image light onto the eye.

The free-form mirror of the above-mentioned front end and the free-form mirror of the above-mentioned rear end can be arranged so that at least two image lights cross each other between the optical path from the free-form mirror of the above-mentioned front end to the free-form mirror of the above-mentioned rear end.

The free-form mirror at the rear end and the coupler can be arranged so that at least two rays of image light intersect between the optical path from the free-form mirror at the rear end to the coupler.

The above image display device may be a head-up display (HUD) device.

The above display panel can be implemented as a holographic display device.

The above light source unit can generate white light by combining red light, green light, and blue light laser light.

The above light source unit may include semiconductor laser light sources arranged in an array shape.

FIG. 1 is a block diagram illustrating the configuration of an image display device according to one embodiment.
FIG. 2 is a drawing explaining the configuration of an image display device according to one embodiment and the positional relationship with a windshield glass and a virtual image.
FIG. 3 is a drawing explaining the configuration of an image display device according to one embodiment.
FIG. 4 is a drawing explaining each control unit included in an image display device according to one embodiment.
FIG. 5 is a drawing explaining the configuration of a scanning optical unit and a beam shaper according to one embodiment.
Fig. 6 is a drawing explaining the configuration of a light source unit according to one embodiment.
Fig. 7 is a block diagram illustrating the configuration of an illumination optical unit according to one embodiment.
Figure 8 is a block diagram illustrating the configuration of an eyepiece optical unit according to one embodiment.
FIG. 9 is a drawing explaining an aspect where light rays intersect in an eyepiece optical unit according to one embodiment.
FIG. 10 and FIG. 11 are drawings explaining the configuration of an image display device according to one embodiment.
FIG. 12 is a drawing explaining the configuration of a scanning optical unit and a beam shaper according to another embodiment.
Fig. 13 is a drawing explaining the configuration of a light source unit according to another embodiment.
Fig. 14 is a drawing explaining the configuration of a light source unit according to another embodiment.

Hereinafter, embodiments will be described in detail with reference to the attached drawings. However, the scope of the patent application is not limited or restricted by these embodiments. The same reference numerals presented in each drawing represent the same components.

The embodiments described below may be modified in various ways. The embodiments described below are not intended to be limiting in terms of the embodiments, and should be understood to include all modifications, equivalents, or alternatives thereto.

The terms used in the examples are only used to describe specific embodiments and are not intended to limit the embodiments. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this specification, the terms "comprises" or "has" and the like are intended to specify that a feature, number, step, operation, component, part or combination thereof described in the specification is present, but should be understood to not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the embodiments belong. Terms defined in commonly used dictionaries, such as those defined in common usage dictionaries, should be interpreted as having a meaning consistent with the meaning they have in the context of the relevant art, and will not be interpreted in an idealized or overly formal sense unless expressly defined in this application.

In addition, when describing with reference to the attached drawings, the same components will be given the same reference numerals regardless of the drawing numbers, and redundant descriptions thereof will be omitted. When describing an embodiment, if it is determined that a specific description of a related known technology may unnecessarily obscure the gist of the embodiment, the detailed description thereof will be omitted.

FIG. 1 is a block diagram illustrating the configuration of an image display device according to one embodiment.

The image display device (100) may include a scanning optical unit (110), a beam shaper (120), an illuminating optical unit (130), a display panel (140), and an eyepiece optical unit (150).

The injection optical unit (110) can inject laser light.

The beam shaper (120) can receive laser light scanned from the scanning optical unit (110). For example, the laser light scanned from the scanning optical unit (110) can be incident on the beam shaper (120) at approximately a vertical angle. The laser light scanned from the scanning optical unit (110) can be incident at an angle perpendicular to the surface of the beam shaper (120) or an angle similar to the vertical angle. The angle similar to the vertical angle can indicate an angle in which an angle difference with respect to the angle perpendicular to the surface of the beam shaper (120) is less than a predetermined critical angle.

The illumination optical unit (130) can illuminate the display panel (140) with laser light emitted from the beam shaper (120).

The display panel (140) can display an image using laser light illuminated by the illumination optical unit (130). For example, the display panel (140) can generate image light corresponding to the image by passing the laser light illuminated by the illumination optical unit (130). The image light can represent light after the laser light passes through an arbitrary point of the display panel (140). The image light can include a bundle of rays emitted from an arbitrary point of the display panel (140).

The eyepiece optical unit (150) can concentrate image light emitted from the display panel (140) onto the observer's eye.

An image display device (100) according to one embodiment is, for example, a head-up display device equipped in a vehicle, and can display a virtual image by overlapping it on a real scene in front of the vehicle. The image display device (100) can create augmented reality by adding information, etc. to the real scene. However, the application of the image display device (100) to the head-up display device is a simple example, and it can be applied to other devices.

An image display device (100) according to one embodiment can efficiently focus image light emitted from a head-up display device onto the eyes of an observer. For example, the image display device (100) can focus image light onto the eyes of an observer in order to display an image over an entire eye box. By focusing image light onto the eyes of an observer, the image display device (100) can focus different image light onto each of both eyes. Accordingly, the image display device (100) can provide a left-eye image to the left eye of an observer and a right-eye image to the right eye of an observer, thereby providing a three-dimensional image to an observer.

FIG. 2 is a drawing explaining the configuration of an image display device according to one embodiment and the positional relationship with a windshield glass and a virtual image. FIG. 3 is a drawing explaining the configuration of an image display device according to one embodiment.

First, the scanning optical unit (110) can scan laser light to the beam shaper (120). Then, the beam shaper (120) can emit laser light to the illumination optical unit (130). The scanning of laser light by the scanning optical unit (110) and the beam shaper (120) are described in FIGS. 5 and 6 below.

Laser light emitted from the beam shaper (120) can be incident on the illumination optical unit (130). The laser light can be transmitted in the order of the anamorphic lens (131), the first free-form mirror (132), and the second free-form mirror (133) provided in the illumination optical unit (130).

And the corresponding laser light can be incident on the display panel (140) from the second free-form mirror (133). The display panel (140) can display an image using the corresponding laser light. For example, the display panel (140) is a transmissive panel, can receive laser light through the back surface, and can emit image light based on the received laser light. And the image light emitted from the display panel (140) can be incident on the eyepiece optical unit (150).

Next, the image light can be transmitted sequentially to the third free-form mirror (151), the fourth free-form mirror (152), and the combiner (153) provided in the eyepiece optical unit (150). The image light reflected by the combiner (153) is focused on the observer's eye. Accordingly, the observer can recognize a virtual image displayed on the projection plane (11) superimposed on the real scene in front through the windshield glass (10), as illustrated in FIG. 2.

According to one embodiment, the image display device (100) can continuously focus image light on the eyes of an observer by controlling predetermined optical elements. For example, when the position of the observer's eyes changes, the image display device (100) can control the movement or position of the predetermined optical elements based on the eye position information. The image display device (100) can continuously focus image light on the eyes of an observer by controlling the positions of the optical elements, etc. in response to the change in the eye position. Here, the eye position information is information indicating the position of the observer's eyes generated by analysis of predetermined sensing data, etc., and the generation method is not particularly limited. In addition, the generation of the eye position information may be realized by an external device or may be realized by the image display device (100). In addition, although the image light is described as being focused on both eyes of the observer, it may be focused on only one eye.

The image display device (100) can focus different image lights for each of the two eyes. The image display device (100) can allow an observer to perceive a three-dimensional image by providing different image lights to each of the two eyes. For example, the image display device (100) can focus image lights of a left-eye image and image lights of a right-eye image, which have disparities from each other, on each eye.

Below, each component of the image display device (100) is described in detail.

FIG. 4 is a drawing explaining each control unit included in an image display device according to one embodiment. FIG. 5 is a drawing explaining the configuration of a scanning optical unit and a beam shaper according to one embodiment.

The scanning optical unit (110) may include a light source unit (111), a laser scanning unit (for example, a MEMS (Micro Electro Mechanical Systems) scanner (112)), and a parabolic mirror (113). In addition, the scanning optical unit (110) may be placed in a dead space that occurs when the illumination optical unit (130) and the eyepiece optical unit (150) are placed. The dead space may refer to a space remaining other than the space occupied by the illumination optical unit (130) and the eyepiece optical unit (150) within a space defined by the housing of the image display device (100). Therefore, the image display device (100) may be miniaturized.

The light source unit (111) is an optical element that generates laser light and can generate, for example, white light. The specific configuration of the light source unit (111) is described in FIG. 6 below.

The MEMS scanner (112) is an optical element that scans laser light incident from a light source unit (111). For example, the MEMS scanner (112) may be placed at the focal position of the parabolic mirror (113). The laser light scanned by the MEMS scanner (112) is reflected by the parabolic mirror (113) and incident on the beam shaper (120). Here, when the laser light emitted from the focal position of the parabolic mirror (113) is reflected at each point on the parabolic mirror (113), the propagation direction of each reflected light has a characteristic of being approximately parallel to the optical axis of the parabolic mirror (113). The reflected light that is approximately parallel to each other is incident approximately perpendicularly to the surface of the beam shaper (120). In this specification, the optical axis may represent a line indicating an optical path through which light passes.

In addition, the image display device (100) may further include a first control unit (191) that controls a position at which the laser light is incident on the beam shaper (120) based on position information of the observer's eye. More specifically, the first control unit (191) controls the MEMS scanner (112) to control a position at which the laser light reflected on the parabolic mirror (113) is incident on the beam shaper (120). In addition, in the beam shaper (120), even if the position at which the laser light is incident changes, the incident angle of the laser light does not change. Even if the position at which the laser light is incident on the beam shaper (120) changes, the laser light can still be incident at an angle that is approximately perpendicular to the surface of the beam shaper (120). The MEMS scanner (112) may also operate as the first control unit (191).

For reference, the beam shaper (120) according to one embodiment is in a coupled relationship with the position of the eye of the observer in the optical system of the image display device (100). If the position at which the laser light is incident on the beam shaper (120) changes, the position at which the image light is finally focused also changes. Therefore, the image display device (100) can determine the position at which the laser light is incident on the beam shaper (120) according to the change in the position of the eye of the observer. For example, the first control unit (191) can focus the image light in response to the change in position in the direction perpendicular to the optical axis of the eye by controlling the position at which the injected laser light is incident on the beam shaper (120). It can be assumed that the position of the eye of the observer moves in a direction approximately perpendicular to the optical axis. The first control unit (191) can control the MEMS scanner (112) to cause laser light to be incident on a point corresponding to the changed position on the beam shaper (120) in response to the change in the position of the observer's eye. Accordingly, the image display device (100) can continuously focus image light on the observer's eye.

In addition, the MEMS scanner (112) can generate right-eye image light corresponding to different right-eye images and left-eye image light corresponding to different left-eye images by adjusting the position at which the laser light is incident on the beam shaper (120). For example, the MEMS scanner (112) can alternately and time sequentially scan laser light at points corresponding to the left eye and points corresponding to the right eye on the beam shaper (120) by driving at high speed. The laser light incident on the point corresponding to the left eye on the beam shaper (120) can then be converted into left-eye image light by the display panel (140) and focused onto the left eye of the observer. The laser light incident on the point corresponding to the right eye can then be converted into right-eye image light by the display panel (140) and focused onto the right eye. Accordingly, the MEMS scanner (112) can scan laser light so that different right-eye images and left-eye images are provided to the observer while switching at high speed. The image display device can provide the right-eye image and the left-eye image to the observer through high-speed operation of the MEMS scanner (112), thereby allowing the observer to recognize a three-dimensional image.

In FIG. 4, the scanning optical unit (110) is illustrated as including a MEMS scanner (112), but is not limited thereto. In addition to the MEMS scanner (112), the scanning optical unit (110) may include an optical element that scans laser light. In addition to the parabolic mirror (113), the scanning optical unit (110) may include an optical element that causes the laser light to be incident approximately perpendicularly to the beam shaper (120).

The beam shaper (120) is an optical element that transmits laser light reflected by a parabolic mirror (113) to an illumination optical unit (130). The beam shaper (120) can change the direction of propagation of laser light reflected by the parabolic mirror (113) through a diffraction phenomenon, etc. In addition, the beam shaper (120) can change the beam shape of the laser light. The beam shaper (120) can be implemented with a circuit optical element such as a DOE (Diffractive Optics Element), a holographic optical element such as a HOE (Holographic Optical Element), or a diffuser plate.

As described above, the laser light reflected by the parabolic mirror (113) can be incident approximately perpendicularly to the surface of the beam shaper (120). The beam shaper (120) can typically broaden the light beam diameter of the incident laser light to a critical size, thereby changing the shape of the laser light (e.g., originally circular) into a rectangular shape. The shape into which the laser light is changed is not limited to a rectangular shape, and may also have a shape similar to a rectangle. The critical size can be determined according to the design, and can be, for example, a size corresponding to a cone angle of the illumination light in the illumination optical unit (130). The light beam diameter of the laser light can represent the diameter of the laser light with respect to the direction in which the laser light travels.

In addition, the image display device (100) may further include a second control unit (192) that controls the position of the beam shaper (120) based on position information of the observer's eye. For example, the second control unit (192) may control the position of the beam shaper (120) forward and backward with respect to the optical axis. The forward and backward direction with respect to the optical axis may be, for example, a direction that is approximately perpendicular to a surface of the beam shaper (120). The approximately perpendicular direction may be a direction that is perpendicular to or similar to perpendicular to a surface of the beam shaper (120).

As described above, the beam shaper (120) according to one embodiment is in a coupled relationship with the position of the observer's eye in the optical system of the image display device (100). In response to the position of the observer's eye moving back and forth with respect to the optical axis, the second control unit (192) can change the position of the beam shaper (120) to a position corresponding to the change in the position of the observer's eye. Accordingly, even when the observer's eye moves back and forth with respect to the optical axis, the image display device (100) can continue to focus the image light on the observer's eye. However, the method of changing the position of the beam shaper (120) is not limited thereto.

In addition, the image display device (100) can control the content of the image based on the position of the viewer's eyes. For example, when the position of the viewer's eyes changes while a three-dimensional image is displayed at a predetermined point in time, the image display device (100) can change the content of the image to a three-dimensional image at the point in time after the change. For example, the image display device (100) can further include a third control unit (193) that controls the content of the image based on the position information of the viewer's eyes. The third control unit (193) can change the content of the image by controlling the display panel (140). For example, it can be assumed that a three-dimensional image for a first view point is visualized while the position of the viewer's eyes changes to a second view point. In response to the user's eyes moving from the first view point to the second view point, the third control unit (193) can change the content corresponding to the first view point to the content corresponding to the second view point. The content corresponding to the first point of view can represent content of a three-dimensional object observed from the first point of view, and the content corresponding to the second point of view can represent content of a three-dimensional content observed from the second point of view. Accordingly, the image display device (100) can continuously provide an image appropriate for the corresponding point of view to the observer even if the position of the observer's eyes changes.

Fig. 6 is a drawing explaining the configuration of a light source unit according to one embodiment.

The light source unit (111) can generate white light by combining red, green, and blue laser light. Combining laser light can also be referred to as multiplexing. For example, as illustrated in FIG. 6, the light source unit (111) can include an R light source unit (111-1a), a G light source unit (111-1b), a B light source unit (111-1c), a collimating lens (111-2a) to a collimating lens (111-2c), a dichroic mirror (111-3a), and a dichroic mirror (111-3b).

Each of the R light source unit (111-1a), the G light source unit (111-1b), and the B light source unit (111-1c) can emit laser light having a peak intensity in a respective band. The R light source unit (111-1a) can emit red light as laser light having a peak intensity in a red wavelength band. The G light source unit (111-1b) can emit green light as laser light having a peak intensity in a green wavelength band. The B light source unit (111-1c) can emit blue light as laser light having a peak intensity in a blue wavelength band.

The laser light source used in the light source unit (111) is not limited. For example, a semiconductor laser light source can be used as the laser light source. For example, a GaInP quantum well structure laser diode using a GaInP semiconductor can be used as the R light source unit (111-1a), and a GaInN quantum well structure laser diode using a GaInN semiconductor can be used as the G light source unit (111-1b) and the B light source unit (111-1c). Since the laser light source is implemented as a semiconductor laser light source, the light source unit (111) can be miniaturized.

Each of the laser lights emitted from the R light source unit (111-1a), the G light source unit (111-1b), and the B light source unit (111-1c) becomes approximately parallel laser light by passing through the corresponding collimating lens (111-2a) to the collimating lens (111-2c). Thereafter, the red light from the R light source unit (111-1a) passes through the color separation mirror (111-3a) and the color separation mirror (111-3b). The optical path of the green light emitted from the G light source unit (111-1b) is switched by the color separation mirror (111-3a). The color separation mirror (111-3a) is a mirror that has the property of transmitting light with a longer wavelength than red light and reflecting green light. The green light whose optical path is switched by the color separation mirror (111-3a) can be combined with the red light. A light beam bundle of combined green light and red light passes through a color separation mirror (111-3b). The color separation mirror (111-3b) is a mirror having a characteristic of transmitting light with a longer wavelength than green light and reflecting blue light. The optical path of the blue light emitted from the B light source unit (111-1c) can be switched by the color separation mirror (111-3b). The blue light whose optical path is switched by the color separation mirror (111-3b) can be combined with red light and green light. Therefore, the light source unit (111) can generate white light by combining red light, green light, and blue light. The light source unit (111) emits the white light generated as described above to the MEMS scanner (112).

In addition, the configuration of the light source unit (111) is not limited to what is described above. For example, the light source unit (111) may instead use a semiconductor laser light source including all of the R light source, the G light source, and the B light source. In addition, the light source unit (111) may also emit laser light of a wavelength band other than red light, green light, and blue light.

Fig. 7 is a block diagram illustrating the configuration of an illumination optical unit according to one embodiment.

The illumination optical unit (130) may include an anamorphic lens (131), a first free-form mirror (132), and a second free-form mirror (133).

The anamorphic lens (131) is an optical element that expands laser light incident from the beam shaper (120), and can expand the laser light along at least one of the short axis direction and the long axis direction of the anamorphic lens (131). The anamorphic lens (131) may be, for example, a half cylindrical lens (for example, a lenticular lens). When the anamorphic lens (131) is a lenticular lens, the short axis direction may represent a direction corresponding to a line that briefly crosses a cross-section of one of a plurality of half cylindrical lenses constituting the lenticular lens. For example, in a half cylindrical lens, a direction corresponding to a line that crosses a cross-section orthogonal to an optical axis at the shortest distance may be a short axis direction, and a direction corresponding to a line that crosses it at the longest distance may be a long axis direction. For example, the optical characteristics (e.g., focal length) of the anamorphic lens (131) may be orthogonal to the optical axis, and may also have different curvatures in two directions orthogonal to each other. Efficient illumination of approximately the entire front of the display panel (140) is enabled by the beam shaper (120) and the anamorphic lens (131). One side of the anamorphic lens (131) may have an anamorphic surface, and a formula defining the anamorphic surface of the anamorphic lens (131) is described below. The other side of the anamorphic lens (131) may be a plane, but is not limited thereto.

The first free-form mirror (132) is an optical element that reflects laser light incident from the anamorphic lens (131).

The second free-form mirror (133) is an optical element that emits laser light toward the display panel (140) by reflecting the laser light incident from the first free-form mirror (132).

Through the above-described optical elements having a free-form curve, the image display device can appropriately control the reflection of light, and the image display device (100) can be miniaturized. The free-form curve can represent a non-rotationally symmetrical curve. The equation defining the free-form surface of the first free-form mirror (132) and the second free-form mirror (133) is explained below.

The display panel (140) forms an intermediate image by laser light incident from the second free-form mirror (133). Image light corresponding to the intermediate image can be transmitted to a combiner (153) through several optical elements, and can form a virtual image superimposed on an actual scene. The light formed on the display panel (140) is emitted from the emission side of the display panel (140) to the third free-form mirror (151) of the eyepiece optical unit (150).

In addition, as shown in FIGS. 2 and 3, the display panel (140) is placed between the optical path from the third free-form mirror (151) to the fourth free-form mirror (152) and the optical path from the fourth free-form mirror (152) to the coupler (153). Through this configuration, the eyepiece optical unit (150) can be miniaturized while exhibiting high optical performance.

For reference, the display panel (140) may be implemented as a holographic display device such as an SLM (Spatial Light Modulator). The image display device (100) may display a holographic image using the holographic display device. In this case, the image display device (100) may provide a three-dimensional holographic image to the viewer by displaying different holographic images for each of the two eyes.

Figure 8 is a block diagram illustrating the configuration of an eyepiece optical unit according to one embodiment.

The eyepiece optical unit (150) includes a third free-form mirror (151), a fourth free-form mirror (152), and a coupler (153).

The third free-form mirror (151) is an optical element (e.g., a free-form mirror of the front end) that reflects image light that constitutes an intermediate image emitted from the display panel (140).

The fourth free-form mirror (152) is an optical element (e.g., a rear free-form mirror) that reflects image light incident from the third free-form mirror (151) and emits the image light toward the combiner (153).

The coupler (153) can receive image light from the fourth free-form mirror (152) and reflect a portion of the received image light to the eyes of the observer. For example, the image light emitted from the fourth free-form mirror (152) can be projected onto the coupler (153). The coupler (153) can cause the observer to perceive a virtual image by reflecting a portion of the projection light projected onto the coupler (153) to the eyes of the observer. For example, the coupler (153) can be implemented as a device in which an evaporation film that functions as a half mirror is formed on an observer-side surface (e.g., a reflective surface) of a colorless resin transparent plate. In addition, according to one embodiment, the reflective surface of the coupler (153) is exemplified as having a concave shape, but is not limited thereto, and the reflective surface of the coupler (153) may also have a convex shape. Additionally, instead of the coupler (153), a windshield glass (10) may be used.

The following Figure 9 explains the optical path in the eyepiece optical unit (150).

FIG. 9 is a drawing explaining an aspect where light rays intersect in an eyepiece optical unit according to one embodiment.

According to one embodiment, each optical element may be arranged such that at least two image lights intersect in the optical path from the third free-form mirror (151) to the fourth free-form mirror (152). For example, as illustrated in FIG. 9, image light reflected from any point of the third free-form mirror (151) intersects image light reflected from another point of the third free-form mirror (151) at position (20) and then enters the fourth free-form mirror (152).

Accordingly, the optical system of the image display device (100) according to one embodiment, particularly, the third free-form mirror (151) and the fourth free-form mirror (152), can be miniaturized. However, the form in which the image light intersects in the optical path from the third free-form mirror (151) to the fourth free-form mirror (152) is not particularly limited.

In addition, each optical element is arranged so that light rays of each image height intersect in the optical path from the fourth free-form mirror (152) to the combiner (153). For example, the fourth free-form mirror (152) and the combiner (153) may be arranged so that at least two light rays of the image light intersect in the optical path from the fourth free-form mirror (152) to the combiner (153). By intersecting the light rays of the image light, aberrations may be improved. For example, as illustrated in FIG. 9, light rays of each image height emitted from the fourth free-form mirror (152) may intersect at a position (30) and enter the combiner (153). However, the form in which light rays of each image height intersect in the optical path from the third free-form mirror (152) to the combiner (153) is not particularly limited. The equations defining the free surfaces of the third free-surface mirror (151) and the fourth free-surface mirror (152) are explained below.

Accordingly, the diffusion angle of the light incident on the coupler (153) can be increased. The image light reflected by the coupler (153) can be effectively focused on the observer's eyes. Accordingly, the optical performance of the image display device (100) can be improved. In addition, even when the image display device (100) according to one embodiment is applied to an optical system having a wide field of view (FOV), the optical system can be miniaturized.

Each component of the image display device (100) is described above. As described above, since the image display device (100) is a reflective optical system, it can prevent the occurrence of chromatic aberration due to a difference in wavelength. Therefore, the image display device (100) can display a high-quality image without color bleeding.

FIG. 10 and FIG. 11 are drawings explaining the configuration of an image display device according to one embodiment.

FIG. 10 and FIG. 11 illustrate an example of a configuration in which all optical elements of the image display device (100) described above are arranged. For convenience of explanation, FIG. 11 illustrates only light rays propagating from the center position of each optical element in a bundle of rays passing through each optical element of the image display device (100). However, the arrangement of each optical element of the image display device (100) is not limited to FIG. 10 and FIG. 11.

Below, equations defining a free-form surface are described. For example, equations defining the free-form surfaces of the first free-form mirror (132) and the second free-form mirror (133) provided in the illumination optical unit (130), and the third free-form mirror (151), the fourth free-form mirror (152), and the coupler (153) provided in the eyepiece optical unit (150) are described. The free-form surface of each optical element is defined by the following mathematical expressions 1, 2, and 3 when defining an orthogonal coordinate system (x, y, z) based on a vertex of the free-form surface. In addition, each coefficient of mathematical expression 1 for each optical element is shown in the following Table 1.

[Mathematical formula 1]

[Mathematical formula 2]

[Mathematical formula 3]

In the above mathematical expressions 1 to 3, x may represent the x-coordinate of the surface, y may represent the y-coordinate of the surface, and z may represent the amount of sag of the surface approximately parallel to the z-axis. C may represent the vertex curvature, which may represent 1/radius of curvature. k may represent the conic constant, and C _j may represent the coefficient of the monomial x ^m y ^m , which may represent the coefficient of the free-form surface.

Eyepiece optics (150) Lighting Optics Department (130) Combiner (153) 4th free-form mirror (152) Third free-form mirror (151) Second free-form mirror (133) 1st free-form mirror (132) Vertex curvature 0 0 0 0 0 Conic coefficient 0 0 0 0 0 coefficient of x 0 0 0 0 0 coefficient of y 0 0 0 1.43. E-01 -7.54. E-01 coefficient of x ² -5.19. E-04 6.20. E-04 8.21. E-04 -1.53. E-03 -1.13. E-03 coefficient of xy 0 0 0 0 0 coefficient of y ² -7.43. E-04 4.90. E-03 -3.21. E-03 3.46. E-03 1.16. E-03 coefficient of x ³ 0 0 0 0 0 coefficient of x ² y 3.85E-07 -6.34E-06 -1.40E-06 -5.25E-05 2.00E-05 coefficient of xy ² 0 0 0 0 0 coefficient of y ³ 4.37E-07 2.16E-06 -7.30E-06 -9.95E-06 -1.32E-05 coefficient of x ⁴ -2.57E-10 3.50E-09 1.16E-08 1.99E-07 1.36E-08 coefficient of x ³ y 0 0 0 0 0 coefficient of x ² y ² -1.39E-09 -8.60E-09 7.02E-09 -1.29E-07 -4.60E-07 coefficient of xy ³ 0 0 0 0 0 coefficient of y ⁴ -7.71E-10 2.53E-07 -4.67E-09 -1.96E-07 1.14E-07 coefficient of x ⁵ 0 0 0 0 0 coefficient of x ⁴ y 1.73E-12 -1.73E-11 -2.28E-10 2.48E-09 -1.94E-09 coefficient of x ³ y ² 0 0 0 0 0 coefficient of x ² y ³ 2.85E-12 -7.55E-10 -2.99E-10 9.53E-10 5.39E-09 coefficient of xy ⁴ 0 0 0 0 0 coefficient of y ⁵ 2.30E-12 1.47E-09 3.30E-12 -1.07E-09 7.12E-09 coefficient of x ⁶ 1.58E-15 5.07E-14 6.84E-13 -2.29E-12 1.57E-12 coefficient of x ⁵ y 0 0 0 0 0 coefficient of x ⁴ y ² 1.94E-15 2.77E-13 1.68E-12 8.47E-12 3.81E-11 coefficient of x ³ y ³ 0 0 0 0 0 coefficient of x ² y ⁴ 0 -1.44E-12 5.44E-13 4.40E-12 -5.49E-11 coefficient of xy ⁵ 0 0 0 0 0 coefficient of y ⁶ 0 -3.87E-11 -1.29E-12 -1.74E-12 -1.67E-10 coefficient of x ⁷ 0 0 0 0 0 coefficient of x ⁶ y 0 1.11E-15 0 -1.76E-14 2.51E-13

Above, the definition formula of the free-form surface of each optical element is explained. Next, the mathematical formula defining the anamorphic surface of the anamorphic lens (131) is explained. The anamorphic surface is defined by the following mathematical formula 4 when the rectangular coordinate system (x, y, z) with the vertex of the anamorphic surface as the origin is defined. In addition, each coefficient of the mathematical formula 4 is shown in Table 2 below.

[Mathematical Formula 4]

x: x-coordinate of the surface

y: y coordinate of the surface

z: amount of sag on the surface parallel to the z-axis

CUX: Curvature of x

CUY: curvature of y

KX: conic coefficient of x

KY: conic coefficient of y

AR: 4th order coefficient of rotational symmetry

BR: 6th order coefficient of rotational symmetry

8th order coefficient of CR rotational symmetry

DR: 10th order coefficient of rotational symmetry

AP: 4th order coefficient of non-rotational symmetry

BP: 6th order coefficient of non-rotational symmetry

CP: 8th order coefficient of non-rotational symmetry

DP: 10th order coefficient of non-rotational symmetry

CUX 3.22.E-03 CUY -1.52.E-03 KY 0 AR 0 BR 0 CR 0 DR 0 KX 0 AP 0 BP 0 CP 0 DP 0

The anamorphic surface having the anamorphic lens (131) is described above. Next, examples of position coordinates of each optical element of the image display device (100) will be described. For example, when an orthogonal coordinate system (x, y, z) (see FIGS. 10 and 11) having the center point of the eye box as the origin is defined, the position coordinates of each optical element can be arranged as exemplary coordinates as shown in Tables 3 to 5 below. Each position coordinate in Tables 3 to 5 below represents the center position of each optical element. In addition, the eccentricity of each optical element is also described. In the eccentricity, α, β, and γ can represent the inclination angle when the x-axis, the y-axis, and the z-axis are rotation axes, respectively. The amount (e.g., +) of the inclination angle α and the inclination angle β can represent the angle when rotated counterclockwise about the positive directions (e.g., forward) of the x-axis and y-axis, respectively. The amount (e.g., +) of the inclination angle γ represents the angle when rotated clockwise about the positive direction of the z-axis.

Coordinates (mm) Eccentricity (°) X Y Z α β γ Center point of iBox 0 0 0 0 0 0 Combiner (153) 0 0 800 32.4 0 0 4th free-form mirror (152) 0 -298.3 659.0 92.7 0 0 Third free-form mirror (151) 0 -211.6 607.5 149.7 0 0 Display panel (140) 0 -212.4 643.5 178.7 0 0 Second free-form mirror (133) 0 -391.6 813.7 163.1 0 0 1st free-form mirror (132) 0 -277.9 767.6 -105.6 0 0 Anamorphic lens (131) 0 -513.5 766.9 1.2 0 0 Beam Shaper (120) 0 -514.6 715.5 1.2 0 0

Coordinates (mm) Eccentricity (°) X Y Z α β γ Center point of iBox 0 0 0 0 0 0 Combiner (153) 0 0 750 32.4 0 0 4th free-form mirror (152) 0 -298.3 609.0 92.7 0 0 Third free-form mirror (151) 0 -211.6 557.5 149.7 0 0 Display panel (140) 0 -212.4 593.5 178.7 0 0 Second free-form mirror (133) 0 -391.6 763.7 163.1 0 0 1st free-form mirror (132) 0 -277.9 717.6 -105.6 0 0 Anamorphic lens (131) 0 -513.6 712.1 1.2 0 0 Beam Shaper (120) 0 -514.7 660.7 1.2 0 0

Coordinates (mm) Eccentricity (°) X Y Z α β γ Center point of iBox 0 0 0 0 0 0 Combiner (153) 0 0 850 32.4 0 0 4th free-form mirror (152) 0 -298.3 709.0 92.7 0 0 Third free-form mirror (151) 0 -211.6 657.5 149.7 0 0 Display panel (140) 0 -212.4 693.5 178.7 0 0 Second free-form mirror (133) 0 -391.6 863.7 163.1 0 0 1st free-form mirror (132) 0 -277.9 817.6 -105.6 0 0 Anamorphic lens (131) 0 -513.4 821.5 1.2 0 0 Beam Shaper (120) 0 -514.5 770.1 1.2 0 0

In addition, among the optical elements described above, each optical element arranged in front of the display panel (140) is an Off-Axis optical system (so-called, "axis-separated optical system"), and each optical element of the display panel (140) and the eyepiece optical unit (150) is an On-Axis optical system. Accordingly, an optical system having high optical performance can be realized while satisfying the above-described definition formula, position coordinates, and eccentricity. However, this is merely an example, and whether each optical element is an Off-Axis optical system or an On-Axis optical system can be appropriately changed according to various conditions (such as the above-described definition formula, position coordinates, eccentricity, or required optical performance). FIG. 12 is a drawing explaining the configuration of a scanning optical unit and a beam shaper according to another embodiment. FIG. 13 is a drawing explaining the configuration of a light source unit according to another embodiment.

Fig. 12 illustrates a light source unit (114) in which semiconductor laser light sources are arranged in an array shape instead of the light source unit (111) described above in Figs. 5 and 6. The remaining configuration other than the light source unit (114) can be implemented with the same structure as described above in Figs. 1 to 11.

Fig. 13 illustrates the light source unit (114) described in Fig. 12. As illustrated in Fig. 13, the light source unit (114) includes a laser light source unit (114-1a) to a laser light source unit (114-1d), a collimating lens (114-2a) to a collimating lens (114-2d), a parabolic mirror (114-3), and a collimating lens (114-4).

The laser light source unit (114-1a) to the laser light source unit (114-1d) are arranged in an array form and are light source elements that emit predetermined laser light. In Fig. 13, only four laser light source units referred to as the laser light source unit (114-1a) to the laser light source unit (114-1d) are illustrated, but the number of laser light source units is not limited and may be appropriately changed based on the size of the parabolic mirror (114-3), the required amount of light, etc. For reference, a total of 16 laser light source units arranged in 4 vertical rows and 4 horizontal rows are illustrated in Fig. 12. In addition, the wavelength of the laser light emitted by each laser light source unit is not limited. The laser lights can be combined regardless of the wavelength of each laser light.

The laser light emitted from the laser light source unit (114-1a) to the laser light source unit (114-1d) becomes approximately parallel laser light by passing through the corresponding collimating lens (114-2a) to the collimating lens (114-2d), respectively. This approximately parallel laser light is combined by being reflected by the parabolic mirror (114-3) and focused by the collimating lens (114-4) arranged at the focus position of the parabolic mirror (114-3).

Fig. 14 is a drawing explaining the configuration of a light source unit according to another embodiment.

The light source unit (115) illustrated in Fig. 14 can reduce the influence of speckle noise caused by laser light. Speckle noise is a phenomenon in which laser light interferes with each other when there are fine irregularities on a reflective surface or a transmitting surface, resulting in the generation of bright spots (e.g., bright spots). When speckle noise occurs, the image tends to sparkle, which is not desirable. In addition, since laser light has a narrow band, the emission wavelength is constant, so interference is easy and speckle noise is easy to occur.

Fig. 14 illustrates a light source unit (115) including a condenser lens (115-4), a diffuser plate (115-5), a motor (115-6), and a collimating lens (115-7) instead of the light source unit (111) described above in Figs. 5 and 6. In addition, the configuration other than the light source unit (115) can be implemented in the same manner as the structure described in Figs. 1 to 11.

Similar to the light source unit (111), white light generated by combining each color light by the color separation mirror (115-3a) and the color separation mirror (115-3b) enters the condenser lens (115-4). Each color light can be generated by the R light source unit (115-1a), the G light source unit (115-1b), the B light source unit (115-1c), and the collimating lens (115-2a) to the collimating lens (115-2c).

The condenser lens (115-4) condenses the incident laser light onto the diffuser plate (115-5). Thereafter, the laser light scattered by the diffuser plate (115-5) becomes approximately parallel laser light by passing through the collimating lens (115-7). In other words, the laser light becomes a beam by the collimating lens (115-7). By becoming a beam by the collimating lens (115-7), scanning by the subsequent MEMS scanner (112) can be performed.

Here, in the diffuser plate (115-5), the speckle state of the laser light emitted from the diffuser plate (115-5) changes depending on the location where the laser light reaches. Furthermore, as the motor (115-6) rotates the diffuser plate (115-5), the speckle state of the laser light emitted from the diffuser plate (115-5) changes along with the rotation.

Due to this, speckle noise is averaged and reduced. More specifically, although speckle noise occurs in the emission light at any time, by causing the motor (115-6) to rotate the diffusion plate (115-5) at a high speed (for example, at a speed higher than a predetermined speed), the speckle noise is averaged and it is possible to reduce the speckle noise to a level that is not visible to the naked eye. As a result, the sparkle of the image is reduced.

In addition, the above-described configuration is a simple example, and the above-described optical element may be appropriately changed to another optical element having a similar function.

For example, in the above-described embodiment, it was applied to a head-up display device, but it can also be applied to a head-mounted display device, etc.

It is possible to focus better image light onto the observer's eye.

The devices described above may be implemented as hardware components, software components, and/or a combination of hardware components and software components. For example, the devices and components described in the embodiments may be implemented using one or more general-purpose computers or special-purpose computers, such as, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable array (FPA), a programmable logic unit (PLU), a microprocessor, or any other device capable of executing instructions and responding to them. The processing device may execute an operating system (OS) and one or more software applications running on the operating system. In addition, the processing device may access, store, manipulate, process, and generate data in response to the execution of the software. For ease of understanding, the processing device is sometimes described as being used alone, but those skilled in the art will appreciate that the processing device may include multiple processing elements and/or multiple types of processing elements. For example, the processing device may include multiple processors, or a processor and a controller. Other processing configurations, such as parallel processors, are also possible.

The software may include a computer program, code, instructions, or a combination of one or more of these, which may configure a processing device to perform a desired operation or may, independently or collectively, command the processing device. The software and/or data may be permanently or temporarily embodied in any type of machine, component, physical device, virtual equipment, computer storage medium or device, or transmitted signal waves, for interpretation by the processing device or for providing instructions or data to the processing device. The software may also be distributed over network-connected computer systems and stored or executed in a distributed manner. The software and data may be stored on one or more computer-readable recording media.

The method according to the embodiment may be implemented in the form of program commands that can be executed through various computer means and recorded on a computer-readable medium. The computer-readable medium may include program commands, data files, data structures, etc., alone or in combination. The program commands recorded on the medium may be those specially designed and configured for the embodiment or may be those known to and available to those skilled in the art of computer software. Examples of the computer-readable recording medium include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as CD-ROMs and DVDs, magneto-optical media such as floptical disks, and hardware devices specially configured to store and execute program commands such as ROMs, RAMs, flash memories, etc. Examples of the program commands include not only machine language codes generated by a compiler but also high-level language codes that can be executed by a computer using an interpreter, etc. The above-mentioned hardware devices may be configured to operate as one or more software modules to perform the operations of the embodiment, and vice versa.

Although the embodiments have been described with limited drawings as described above, those skilled in the art can apply various technical modifications and variations based on the above. For example, appropriate results can be achieved even if the described techniques are performed in a different order from the described method, and/or components of the described system, structure, device, circuit, etc. are combined or combined in a different form from the described method, or are replaced or substituted by other components or equivalents.

Therefore, other implementations, other embodiments, and equivalents to the claims are also included in the scope of the claims described below.

100: Image display device
110: Injection Optics Department
111, 114: Light source
112: MEMS scanner
113: Parabolic mirror
120: Beam Shaper
130: Lighting Optics Department
131: Anamorphic lens
132: 1st free-form mirror
133: Second free-form mirror
140: Display panel
150: Eyepiece optics
151: Third free-form mirror
152: 4th free surface mirror

Claims (20)

In the image display device,
A scanning optical unit that scans laser light;
A beam shaper into which laser light injected from the above-mentioned injection optical unit is incident vertically;
An illumination optical section including two reflective optical elements having free-form curves and one anamorphic lens, and illuminating a display panel with laser light emitted from the beam shaper;
The display panel that displays an image using laser light illuminated from the above lighting optical unit; and
An eyepiece optical section including three reflective optical elements having free-form surfaces and focusing image light emitted from the display panel onto the observer's eye
Including,
The above display panel,
It is arranged between the illumination optical unit and the eyepiece optical unit along the propagation path of the laser light.
Image display device. In the first paragraph,
A first control unit that controls the position at which the injected laser light enters the beam shaper based on the position information of the eye
An image display device further comprising: In the second paragraph,
The above injection optical unit is,
Including a laser injection unit,
The above first control unit,
By controlling the above laser injection unit, the position at which the injected laser light is incident on the beam shaper is controlled.
Image display device. In the second paragraph,
The above first control unit,
By controlling the position at which the injected laser light is incident on the beam shaper in response to a change in position in the direction perpendicular to the optical axis of the eye, the image light is focused.
Image display device. In the first paragraph,
A second control unit that controls the position of the beam shaper based on the position information of the eye
An image display device further comprising: In paragraph 5,
The second control unit,
Controlling the position of the above beam shaper forward and backward with respect to the optical axis,
Image display device. In paragraph 5,
The second control unit,
By controlling the position of the beam shaper in response to the eye moving back and forth about the optical axis, the image light is focused.
Image display device. In the first paragraph,
The above beam shaper,
A diffractive optical element (DOE), a holographic optical element (HOE), or a diffuser plate,
Image display device. In the first paragraph,
A third control unit that controls the content of the image based on the position information of the eye
An image display device further comprising: In Article 9,
The third control unit,
Providing distinct right eye and left eye images for both eyes,
Image display device. In the first paragraph,
The above injection optical unit is,
A light source unit that emits the laser light;
A laser scanning unit that scans the laser light emitted from the light source unit; and
A mirror that reflects the laser light injected by the laser injection unit, thereby causing the laser light to enter the beam shaper.
An image display device further comprising: In Article 11,
The above laser injection unit,
Implemented with a MEMS (Micro Electro Mechanical Systems) scanner,
The above mirror,
Implemented with a parabolic mirror,
Image display device. In Article 11,
The above light source part,
A condensing lens that concentrates the laser light onto a diffuser;
The diffusion plate that scatters the laser light collected by the collecting lens;
A collimating lens that emits parallel light generated by collimating the laser light scattered by the diffuser to the laser injection unit; and
A motor that rotates the above diffuser plate
An image display device including: In the first paragraph,
The above eyepiece optical part is,
A free-form mirror of the front end that reflects image light emitted from the display panel;
A back end free-form mirror that additionally reflects the image light reflected by the free-form mirror of the above-mentioned front end; and
A combiner that focuses the image light onto the eye by additionally reflecting the image light reflected by the free-form mirror at the rear end.
An image display device including: In Article 14,
The free-form mirror of the above-mentioned front end and the free-form mirror of the above-mentioned rear end are,
At least two image lights are arranged to cross each other between the optical path from the free-form mirror of the front end to the free-form mirror of the rear end.
Image display device. In Article 14,
The above rear-end free-form mirror and the above coupler are,
At least two rays of image light are arranged to intersect between the optical path from the free-form mirror at the rear end to the combiner.
Image display device. In the first paragraph,
The above image display device,
A head-up display (HUD) device,
Image display device. In the first paragraph,
The above display panel,
Implemented as a holographic display device,
Image display device. In Article 11,
The above light source part,
By combining red, green, and blue laser light, white light is generated.
Image display device. In Article 11,
The above light source part,
Semiconductor laser sources arranged in an array configuration
An image display device including:

Images