Patent Application
20210385430
This application claims priority to Japanese Patent Application No. 2018-205979 (filed on Oct. 31, 2018), the contents of which are incorporated herein by reference in its entirety.
The present disclosure relates to an image display device, an image display system, and a moving body.
In a recent year, an image display device has been known that provides a stereoscopic view by projecting a parallax image to both eyes of a user by providing an optical element which defines a direction of image light. This technique is described in, for example, Japanese Unexamined Patent Publication JP-A 2012-141331.
An image display device according to an embodiment of the disclosure includes a display panel, a barrier panel, and a controller. The display panel includes display-pixels arranged along a parallax direction which gives parallax to both eyes of a user. The barrier panel is positioned so as to overlap the display panel. The barrier panel includes barrier-pixels arranged along the parallax direction. The controller is configured so that first display regions for displaying a first image projected on the first eye of the user and second display regions for displaying a second image projected on the second eye of the user, can be set in the display panel. The controller is configured so that the first display regions and the second display regions can be set so that the first display regions and the second display regions are alternately arranged along the parallax direction. The controller is configured so that first transparent regions and second transparent regions can be set in the barrier panel, image light emitted from the display panel being transmitted through the first transparent regions at a first transmittance and the image light being transmitted through the second transparent regions at a second transmittance lower than the first transmittance. The controller is configured so that the first transparent regions and the second transparent regions can be set so that the first transparent regions and the second transparent regions are alternately arranged along the parallax direction. The controller is configured so that eye-position information representing an eye-position of at least one of the first eye and the second eye can be acquired. The controller is configured so that a reference position can be set in at least one of the display panel and the barrier panel, based on the eye-position information. The controller is configured so that division regions can be set for at least one of the display panel and the barrier panel, based on a distance from the reference position along the parallax direction. The controller is configured so that at least one of a parallax image pitch and a barrier pitch can be set for each of the division regions. The parallax image pitch represents a pitch at which the first display regions and the second display regions are alternately arranged in the display panel. The barrier pitch represents a pitch at which the first transparent regions and the second transparent regions are alternately arranged in the barrier panel.
An image display system according to another embodiment of the disclosure includes an image display device and a reflective member. The image display device includes a display panel, a barrier panel, and a controller. The display panel includes display-pixels arranged along a parallax direction which gives parallax to both eyes of a user. The barrier panel is positioned so as to overlap the display panel. The barrier panel includes barrier-pixels arranged along the parallax direction. The controller is configured so that first display regions for displaying a first image projected on the first eye of the user and second display regions for displaying a second image projected on the second eye of the user, can be set in the display panel. The controller is configured so that the first display regions and the second display regions can be set so that the first display regions and the second display regions are alternately arranged along the parallax direction. The controller is configured so that first transparent regions and second transparent regions can be set in the barrier panel, image light emitted from the display panel being transmitted through the first transparent regions at a first transmittance and the image light being transmitted through the second transparent regions at a second transmittance lower than the first transmittance. The controller is configured so that the first transparent regions and the second transparent regions can be set so that the first transparent regions and the second transparent regions are alternately arranged along the parallax direction. The controller is configured so that eye-position information representing an eye-position of at least one of the first eye and the second eye can be acquired. The controller is configured so that a reference position can be set in at least one of the display panel and the barrier panel, based on the eye-position information. The controller is configured so that division regions can be set for at least one of the display panel and the barrier panel, based on a distance from the reference position along the parallax direction. The controller is configured so that at least one of a parallax image pitch and a barrier pitch can be set for each of the division regions. The parallax image pitch represents a pitch at which the first display regions and the second display regions are alternately arranged in the display panel. The barrier pitch represents a pitch at which the first transparent regions and the second transparent regions are alternately arranged in the barrier panel. The reflective member reflects image light related to the parallax image to cause the image light to reach the first eye and the second eye of the user.
A moving body according to still another embodiment of the disclosure mounts an image display system. The image display system includes an image display device and a reflective member. The image display device includes a display panel, a barrier panel, and a controller. The display panel includes display-pixels arranged along a parallax direction which gives parallax to both eyes of a user. The barrier panel is positioned so as to overlap the display panel. The barrier panel includes barrier-pixels arranged along the parallax direction. The controller is configured so that first display regions for displaying a first image projected on the first eye of the user and second display regions for displaying a second image projected on the second eye of the user, can be set in the display panel. The controller is configured so that the first display regions and the second display regions can be set so that the first display regions and the second display regions are alternately arranged along the parallax direction. The controller is configured so that first transparent regions and second transparent regions can be set in the barrier panel, image light emitted from the display panel being transmitted through the first transparent regions at a first transmittance and the image light being s transmitted through the second transparent regions at a second transmittance lower than the first transmittance. The controller is configured so that the first transparent regions and the second transparent regions can be set so that the first transparent regions and the second transparent regions are alternately arranged along the parallax direction. The controller is configured so that eye-position information representing an eye-position of at least one of the first eye and the second eye can be acquired. The controller is configured so that a reference position can be set in at least one of the display panel and the barrier panel, based on the eye-position information. The controller is configured so that division regions can be set for at least one of the display panel and the barrier panel, based on a distance from the reference position along the parallax direction. The controller is configured so that at least one of a parallax image pitch and a barrier pitch can be set for each of the division regions. The parallax image pitch represents a pitch at which the first display regions and the second display regions are alternately arranged in the display panel. The barrier pitch represents a pitch at which the first transparent regions and the second transparent regions are alternately arranged in the barrier panel. The reflective member reflects image light related to the parallax image to cause the image light to reach the first eye and the second eye of the user.
As illustrated in
The display panel 20 is configured to be able to display an image to be viewed by a user. The barrier panel 30 is configured to allow part of image light emitted from the display panel 20 to reach one of a left eye 5L and a right eye 5R of the user and to allow the other part of the image light to reach the other eye of the user. That is, the barrier panel 30 is configured to divide traveling directions of at least part of the image light into the left eye 5L and the right eye 5R of the user. Compared to the display panel 20, the barrier panel 30 may be located closer to or farther from the user when viewed from the user. The image light traveling in a direction limited by the barrier panel 30 can reach the left eye 5L and the right eye 5R of the user as different image light. As a result, the user can view different images for each of the left eye 5L and the right eye 5R. That is, the image display device 10 can be configured to project a parallax image onto both eyes of the user. The parallax image is an image projected on each of the left eye 5L and the right eye 5R of the user and is an image which gives parallax to both eyes of the user. The user can see the image stereoscopically by viewing the parallax image by the left eye 5L and the right eye 5R. A direction which gives parallax to both eyes of the user is also called a parallax direction. The parallax direction corresponds to a direction in which the left eye 5L and the right eye 5R of the user are lined up. The left eye 5L and the right eye 5R of the user are also referred to as a first eye and a second eye of the user, respectively.
The controller 50 is connected to each component of the image display device 10 and is configured to be able to control each component. The controller 50 may be configured as, for example, a processor. The controller 50 may include one or more processors. The processor may include a general-purpose processor which loads a specific program and executes a specific function and a dedicated processor specialized for a specific process. The dedicated processors may include an application specific IC (Application Specific Integrated Circuit: ASIC). The processor may include a Programmable Logic Device (PLD). The PLD may include an FPGA (Field-Programmable Gate Array). The controller 50 may be either a System-on-a-Chip (SoC) or a System In a Package (SiP) in which one or a plurality of processors cooperate. The controller 50 may include a storage unit, and the storage unit may store various kinds of information, a program for operating each component of the image display device 10, and the like. The storage unit may be composed of, for example, a semiconductor memory or the like. The storage unit may be configured to function as a work memory of the controller 50.
The acquisition unit 40 is configured to be able to acquire information regarding an eye-position of at least one of the left eye 5L and the right eye 5R of the user and is configured to be able to output the information to the controller 50. The acquisition unit 40 may be configured to be able to acquire information regarding the eye-positions of the left eye 5L and the right eye 5R of the user. The information regarding the eye-position of at least one of the left eye 5L and the right eye 5R of the user is also referred to as eye-position information. The acquisition unit 40 may be configured to be connectable to a camera. In the case where the acquisition unit 40 is connected to a camera, the acquisition unit 40 may be configured to be able to acquire a captured image from the camera and acquire the eye-position information based on the captured image.
The camera may be configured to be capable of detecting the eye-position of at least one of the left eye 5L and the right eye 5R of the user. The eye-position of at least one of the left eye 5L and the right eye 5R of the user is also referred to as an eye-position. The camera may be configured to be able to output the eye-position information based on an eye-position detection result. The camera may be configured to be capable of capturing an image of a user's face and to be able to detect the eye-position based on the captured image. The camera may be configured to be able to detect the eye-position as coordinates in three-dimensional space based on the captured image. The camera may include a plurality of imaging elements. The camera may be configured so that the eye-position can be detected as the coordinates in the three-dimensional space based on the captured image of each imaging element.
The acquisition unit 40 may include a camera. The acquisition unit 40 may be configured to be connectable to a camera provided as a configuration separate from the image display device 10. The acquisition unit 40 may include an input terminal configured to be capable of inputting a signal from the camera. The camera may be configured to be directly connectable to the input terminal. The camera may be configured to be indirectly connectable to the input terminal via a shared network. The acquisition unit 40 without a camera may include an input terminal configured so that a video signal can be inputted from the camera. The acquisition unit 40 may be configured to be able to detect the eye-position based on the video signal inputted to the input terminal.
The acquisition unit 40 may include, for example, a sensor. The sensor may be an ultrasonic sensor, an optical sensor, or the like. The acquisition unit 40 may be configured so that the position of a user's head can be detected by a sensor and the eye-position can be detected based on the position of the head. The acquisition unit 40 may be configured so that the eye-position can be detected as coordinates in three-dimensional space by one or two or more sensors.
The acquisition unit 40 is configured to be able to calculate a distance between the left eye 5L and the right eye 5R and the barrier panel 30 as an observation distance (P) based on the detection result of the eye-position. The acquisition unit 40 may be configured so that a difference between a Z coordinate of the eye-position and a Z coordinate of the barrier panel 30 can be calculated as the observation distance (P). The acquisition unit 40 may be configured to be able to calculate an inter-eye distance (E) based on the detection result of the eye-position.
The image display device 10 does not have to include the acquisition unit 40. When the image display device 10 does not include the acquisition unit 40, the controller 50 may include an input terminal provided outside the device so as to be able to input a signal from a device for detecting the eye-position of the eye of the user. A device provided outside the device which can detect the eye-position of the eye of the user is also referred to as a detection device outside the device. The detection device outside the device may be configured to be connectable to the input terminal. The detection device outside the device may be configured to enable the use of an electrical signal and an optical signal as a transmission signal to the input terminal. The detection device outside the device may be configured to be indirectly connectable to the input terminal via a shared network.
The display panel 20 is configured to be able to display a left-eye image which is viewed by the left eye 5L of the user and a right-eye image which is viewed by the right eye 5R of the user. The display panel 20 may include a liquid crystal device such as an LCD (Liquid Crystal Display). The display panel 20 may include a self-luminous device such as an organic EL (Electro-Luminescence) or an inorganic EL. In the case where the display panel 20 includes the self-luminous device, the barrier panel 30 is located closer to the user than the display panel 20.
As illustrated in
As illustrated in
As illustrated in
The plurality of light-transmitting regions 31 are configured so that the image light related to the left-eye image reaches the left eye 5L of the user, and also the plurality of light-transmitting regions 31 are configured so that the image light related to the right-eye image reaches the right eye 5R of the user. The plurality of dimming regions 32 are configured so as to prevent or make it difficult for the image light related to the left-eye image to reach the right eye 5R of the user, and also the plurality of dimming regions 32 are configured to prevent or make it difficult for the image light related to the right-eye image to reach the left eye 5L of the user. The barrier panel 30 may be configured so that the user can view the right-eye image by the right eye 5R, while the right-eye image is not viewed or is difficult to be viewed by the left eye 5L. The barrier panel 30 may be configured so that the user can view the left-eye image by the left eye 5L, while the left-eye image is not viewed or is difficult to be viewed by the right eye 5R. The barrier panel 30 is configured to define the direction of image light for a parallax image including a left-eye image and a right-eye image by being configured to form a plurality of light-transmitting regions 31 and a plurality of dimming regions 32. The direction of the image light related to the parallax image is also referred to as a light direction of the parallax image.
The plurality of light-transmitting regions 31 and the plurality of dimming regions 32 are arranged alternately in the X-axis direction. A boundary between each light-transmitting region 31 and each dimming region 32 may be along the Y-axis direction as illustrated in
The shapes of the plurality of light-transmitting regions 31 and the plurality of dimming regions 32 may be determined based on the shapes of the plurality of left-eye image display regions 21L and the plurality of right-eye image display regions 21R. Conversely, the shapes of the plurality of left-eye image display regions 21L and the plurality of right-eye image display regions 21R may be determined based on the shapes of the plurality of light-transmitting regions 31 and the plurality of dimming regions 32.
It is assumed that the barrier panel 30 is constituted by a liquid crystal shutter. The liquid crystal shutter may be configured to control the light transmittance based on an applied voltage. The liquid crystal shutter may be configured to be constituted by a plurality of pixels, and the light transmittance in each pixel may be controllable. The liquid crystal shutter may be configured so that a region having a high light transmittance or a region having a low light transmittance can be formed in an arbitrary shape. In the case where the barrier panel 30 is constituted by a liquid crystal shutter, the plurality of light-transmitting regions 31 may have a transmittance equal to or higher than the first transmittance. In the case where the barrier panel 30 is constituted by a liquid crystal shutter, the plurality of dimming regions 32 may have a transmittance of equal to or less than the second transmittance.
The display panel 20 and the barrier panel 30 each include a plurality of pixels. The plurality of pixels of the display panel 20 are also referred to as a plurality of display-pixels. The plurality of pixels of the barrier panel 30 is also referred to as a plurality of barrier-pixels. It is assumed that the plurality of display-pixels and the plurality of barrier-pixels are arranged along the parallax direction. An arrangement pitch of the plurality of display-pixels in the parallax direction and an arrangement pitch of the plurality of barrier-pixels in the parallax direction may be the same or different. In the embodiment, it is assumed that the arrangement pitch of the plurality of display-pixels in the parallax direction and the arrangement pitch of the plurality of barrier-pixels in the parallax direction are the same. In this case, each display-pixel and each barrier-pixel are associated with each other. Each barrier-pixel may be controllably configured to function as any of the plurality of light-transmitting regions 31 and the plurality of dimming regions 32. The controller 50 may be configured to be able to synchronize the control of each display-pixel with the control of each barrier-pixel associated with the control. Image quality can be improved by configuring control of display-pixels and barrier-pixels associated with each other in a synchronous manner.
In the case where the display panel 20 and the barrier panel 30 include the same pixel arrangement pitch, the display panel 20 and the barrier panel 30 have a common pixel configuration. The display panel 20 may include a color filter for expressing each color of RGB (Red Green Blue) in the display image. The barrier panel 30 does not have to include a color filter. Since the barrier panel 30 does not include a color filter, the light transmittance of the barrier panel 30 can be increased. When the display panel 20 and the barrier panel 30 have a pixel configuration common to each other, members other than the color filter can be commonly used in the display panel 20 and the barrier panel 30. By making the display panel 20 and the barrier panel 30 have a common pixel configuration, the cost of the member can be reduced.
The barrier panel 30 may be located closer to or farther from the user than the display panel 20 when viewed from the user located on a positive side of the Z axis. It is assumed that the barrier panel 30 is located closer to the user than the display panel 20 when viewed from the user, as illustrated in
It is assumed that the left eye 5L and the right eye 5R of the user are located apart from the barrier panel 30 by a distance represented by P. The distance between the left eye 5L and the right eye 5R of the user and the barrier panel 30 is also referred to as the observation distance. A distance between the left eye 5L and the right eye 5R along the parallax direction is also called an inter-eye distance and is represented by E. A distance from the barrier panel 30 to the display panel 20 is also called a gap and is represented by g. A pitch at which the plurality of light-transmitting regions 31 and the plurality of dimming regions 32 are alternately arranged in the X-axis direction is also called a barrier pitch and is represented by Bp. The controller 50 is configured to be able to control the barrier pitch by being configured to be able to control the plurality of light-transmitting regions 31 and the plurality of dimming regions 32 of the barrier panel 30. A pitch at which the plurality of left-eye image display regions 21L and the plurality of right-eye image display regions 21R are alternately arranged in the X-axis direction is also called a parallax image pitch and is represented by k. The controller 50 is configured to be able to control the parallax image pitch by being configured to be able to control the plurality of left-eye image display regions 21L and the plurality of right-eye image display regions 21R of the display panel 20.
The display panel 20 is configured so that a plurality of left eye visible regions 22L and a plurality of left eye non-visible regions 23L can be formed. The plurality of left eye visible regions 22L are configured to be viewable by the left eye 5L of the user through the plurality of light-transmitting regions 31. The plurality of left eye non-visible regions 23L are configured to be not viewable or difficult to be viewed by the left eye 5L of the user by the plurality of dimming regions 32. The plurality of left eye visible regions 22L and the plurality of left eye non-visible regions 23L are alternately arranged in the X-axis direction. A position of a boundary between each left eye visible region 22L and each left eye non-visible region 23L is determined by the position of the boundary between each light-transmitting region 31 and each dimming region 32, the distance from the barrier panel 30 to both eyes of the user, and the gap.
The display panel 20 is configured so that a plurality of right eye visible regions 22R and a plurality of right eye non-visible regions 23R can be formed. The plurality of right eye visible regions 22R are configured to be viewable by the right eye 5R of the user through the plurality of light-transmitting regions 31. The plurality of right eye non-visible regions 23R are configured so as to be not viewable or difficult to be viewed by the right eye 5R of the user by the plurality of dimming regions 32. The plurality of right eye visible regions 22R and the plurality of right eye non-visible regions 23R are alternately arranged in the X-axis direction. A position of a boundary between each right eye visible region 22R and each right eye non-visible region 23R is determined by the position of the boundary between each light-transmitting region 31 and each dimming region 32, the distance from the barrier panel 30 to both eyes of the user, and the gap.
The display panel 20 may be configured to be capable of displaying a parallax image so that the plurality of left-eye image display regions 21L coincide with the plurality of left eye visible regions 22L. The display panel 20 may be configured to be capable of displaying a parallax image so that the plurality of right-eye image display regions 21R coincide with the plurality of right eye visible regions 22R. That is, the display panel 20 may be configured to be capable of displaying a parallax image based on the position of the boundary between each light-transmitting region 31 and each dimming region 32, the distance from the barrier panel 30 to both eyes of the user, and the gap.
In the case where the plurality of left eye visible regions 22L and the plurality of right eye visible regions 22R overlap at least in part along the X-axis direction, crosstalk can occur, with some of the plurality of left-eye images projected onto the right eye 5R and some of the plurality of right-eye images projected onto the left eye 5L. Crosstalk deteriorates the image quality of the parallax image projected on the user.
In the case where the plurality of left eye visible regions 22L and the plurality of right eye visible regions 22R are alternately arranged in the X-axis direction without overlapping each other, the left eye 5L can view only the plurality of left-eye images, and the right eye 5R can view only the plurality of right-eye images. In this case, crosstalk can be reduced. A state in which the left eye 5L can view only the plurality of left-eye images and the right eye 5R can view only the plurality of right-eye images, can be realized in the case where the observation distance is the optimum viewing distance (OVD).
In the case where the observation distance becomes the OVD, the following expressions (1) and (2) are established based on a geometrical relationship illustrated in
According to the expressions (1) and (2), the barrier pitch (Bp) and the parallax image pitch (K) are uniquely determined based on the inter-eye distance (E), the gap (g), and the observation distance (P). In other words, by configuring the controller 50 to be able to control the display panel 20 and the barrier panel 30 based on the values of the barrier pitch and the parallax image pitch determined by the expressions (1) and (2), the condition that the observation distance becomes the OVD is satisfied. The barrier pitch and the parallax image pitch which satisfy the condition that the observation distance becomes the OVD are also referred to as the optimum barrier pitch and the optimum parallax image pitch, respectively. The controller 50 is configured so that the eye-position information of the user can be acquired from the acquisition unit 40, the detection device outside the device, or the like, and the controller 50 may be configured to be able to calculate the optimum barrier pitch and the optimum parallax image pitch based on the eye-position information.
In the case where the controller 50 is configured to be able to control both the barrier pitch and the parallax image pitch, the condition that any observation distance becomes the OVD can be satisfied. In the case where the controller 50 is configured so that either the barrier pitch or the parallax image pitch can be changed only within a predetermined range, the observation distance which can satisfy the condition of OVD is limited to a narrow range based on the expressions (1) and (2). In other words, the controller 50 is configured to be able to control both the barrier pitch and the parallax image pitch, thereby expanding the range of the observation distances that can satisfy the condition of OVD.
The controller 50 is configured to be able to control the display panel 20 and the barrier panel 30 so as to satisfy the condition that the observation distance becomes the OVD. The controller 50 may be configured to be able to control the shape and position of the plurality of left-eye image display regions 21L and the plurality of right-eye image display regions 21R on the display panel 20 so that the condition that the observation distance becomes the OVD is satisfied and the controller 50 may be configured to be able to control the parallax image pitch. The controller 50 may be configured so that the shape and position of the plurality of light-transmitting regions 31 and the plurality of dimming regions 32 can be controlled in the barrier panel 30 so as to satisfy the condition that the observation distance becomes the OVD and the controller 50 may be configured to be able to control the barrier pitch.
As illustrated in
Among the image light traveling toward the left eye 5L and the right eye 5R of the user, the image light traveling in a direction having an inclination with respect to the normal of the surface of the cover 24 is refracted at the surface of the cover 24. Based on Snell's law, the larger the emission angle of the image light emitted from the display element 25, the shallower the virtual image 25Q of the display element 25 looks.
The thickness of the cover 24 is represented by t. That is, the actual distance from the surface of the cover 24 to the display element 25 is represented by t. An emission angle of the image light emitted from the display element 25 from the surface of the cover 24 is represented by θ1. In the case where the emission angle is θ1, an angle of incidence on the surface of the cover 24 is represented by θ2. The unit of θ1 and θ2 is radian. Based on Snell's law, the following expression (3) is established between θ1 and θ2.
sin θ1=n×sin θ2 (3)
Based on n>1, it can be said that θ1 is larger than θ2.
A position facing the user when the display panel 20 is viewed by the user is also called a display reference position. It is assumed that the display reference position is set in the display surface 26 of the display panel 20.
The display reference position may be set to a position where θ1=θ2=0 is satisfied in display panel 20 and the path of the image light reaching one of the left eye 5L and the right eye 5R of the user intersects the display surface 26. The display reference position may be set to a position where θ1=θ2=0 is satisfied in display panel 20 and the path of the image light reaching a predetermined point located between the left eye 5L and the right eye 5R intersects the display surface 26. In the case where the user looks directly at the image display device 10, the display reference position may be set to a position of a foot of a perpendicular line drawn from a point where one of the left eye 5L and the right eye 5R of the user is located with respect to the display surface 26. The display reference position may be set at a position of the foot of the perpendicular line drawn from a predetermined point located between the left eye 5L and the right eye 5R with respect to the display surface 26. In the case where the user views the image display device 10 through an optical system including a reflective member 60 (see
It is assumed that, on the display surface 26, the x-coordinate including the display reference position is defined along the X-axis. As illustrated in
It is assumed that the virtual image 25Q of the display element 25 appears to be located at the depth represented by d (x). That is, the apparent depth of the display element 25 is represented by d(x). The apparent depth of the display element 25 is expressed by the following expression (4).
The virtual image 250Q of the display element 250, located at the point represented by x0, appears to be located at the depth represented by d(x0). The virtual image 251Q of the display element 251 located at the point represented by x1 appears to be located at the depth represented by d(x1). Here, d(x0) is expressed by the following expression (5).
In the case where the emission angle of the image light emitted from the display element 25 is 0, the virtual image 250Q of the display element 250 appears to be located at the depth represented by t/n. That is, the apparent depth of the display element 250 is expressed in t/n.
Based on the expression (2), the value of d(x) becomes the maximum value in the case where θ1=θ2=0. On the other hand, as θ1 increases in a range of 0<θ1<n/2, the value of d(x) decreases and approaches 0. In the case where the user looks at the display panel 20, the emission angle of the image light emitted from the display element 250 at the display reference position becomes 0. The apparent depth of the display element 250 at the display reference position is greater than the apparent depth of the display element 251 located away from the display reference position in the X-axis direction. That is, d(x0) becomes the maximum value of d(x).
The more distant the position of the display element 25 is from the display reference position along the X axis, θ1 becomes larger in the range of 0<θ1<n/2. As a result, the farther the x-coordinate of the display element 25 is from the display reference position, the closer its virtual image 25Q appears to be to the display surface 20a. That is, the farther the display element 25 is located at the x-coordinate from the display reference position, the shallower the apparent depth (d) of the display element 25. The relationship between the distance from the display reference position and the apparent depth (d) is illustrated in a graph of
The gap (g) illustrated in
Here, g(x) can be represented as a continuous function with the X coordinate as an argument. The controller 50 is configured to be able to determine the optimum parallax image pitch so that the condition that the observation distance becomes the OVD is satisfied based on the value of g(x) at points with different x-coordinates originating from the display reference position on the display panel 20.
The position facing the user when the barrier panel 30 is viewed from the user is also called a barrier reference position. The barrier reference position may be set based on the display reference position. It is assumed that the barrier reference position is set as a position facing the display reference position on the barrier panel 30. The controller 50 is configured to be able to determine the optimum barrier pitch so that the condition that the observation distance becomes the OVD is satisfied based on the value of g(x) at points with different x-coordinates originating from the barrier reference position on the barrier panel 30.
The display reference position and the barrier reference position are also collectively referred to as a common reference position. The controller 50 may be configured to be able to determine the optimum parallax image pitch and the optimum barrier pitch based on the common reference position.
It is assumed that the distance between the display panel 20 and the barrier panel 30 is small enough for the observation distance. That is, it is assumed that P>>g(x) is established. In this case, according to the expressions (1) and (2), the parallax image pitch (k) and the barrier pitch (Bp) can be regarded as equal. Hereinafter, it is assumed that the parallax image pitch and the barrier pitch are equal.
In the case where the parallax image pitch and the barrier pitch are equal, the parallax image pitch and the barrier pitch are also collectively referred to as a common pitch. The controller 50 may be configured so that the parallax image pitch and the barrier pitch can be controlled as the common pitch. The common pitch which satisfies the condition that the observation distance becomes the OVD is also called an optimum common pitch. The display panel 20 and the barrier panel 30 are also collectively referred to as a parallax panel.
As illustrated in
In the case where the display panel 20 and the barrier panel 30 include pixels, the parallax image pitch and the barrier pitch are each determined in a unit of the pixel size. That is, the common pitch is set to the natural number multiple of the pixel size. Each pixel of the display panel 20 and the barrier panel 30 has a predetermined width in the X direction. The controller 50 is configured to be able to control the common pitch to a value which is the natural number multiple of the width of each pixel in the X direction. That is, the controller 50 is configured so that the common pitch is discretized to a value which is the natural number multiple of the width of the pixel in the X direction. In this case, the optimal common pitch is represented as the output of a stepped discontinuous function with the x coordinate as the input, as illustrated by a solid line in
As illustrated in
It is assumed that the plurality of division regions 17 include a first division region 17a, a second division region 17b, a third division region 17c, and a fourth division region 17d. The number of division regions 17 is not limited to four, and may be three or less, or five or more. The boundary of each division region 17 may coincide with the boundary of the predetermined section corresponding to the discretized optimum common pitch. The first division region 17a is set as a region from the common reference position to a point represented by x11. The second division region 17b is set as a region from the point represented by x11 to a point represented by x12. The third division region 17c is set as a region from the point represented by x12 to a point represented by x13. The fourth division region 17d is set as a region from the point represented by x13 to a point represented by x14.
The first division region 17a is adjacent to the second division region 17b with the point represented by x11 as the boundary. The controller 50 may make the optimum common pitch in the second division region 17b one pixel shorter than the optimum common pitch in the first division region 17a adjacent to the side closer to the common reference position.
Up to this point, the configuration when the barrier panel 30 is located closer to the user than the display panel 20 when viewed from the eyes of the user is described. As illustrated in
The apparent gap at each position of the configuration illustrated in
Regardless of the positional relationship between the display panel 20 and the barrier panel 30 as seen from the eyes of the user, it is assumed that the controller 50 is configured to be able to control the pixels in the first division region 17a of the barrier panel 30 as illustrated in
In the case where the barrier panel 30 is located closer to the user than the display panel 20 as seen by the user, the controller 50 may be configured to be able to control the pixels in the second division region 17b of the barrier panel 30 as illustrated in
In the case where the display panel 20 is located closer to the user than the barrier panel 30 as seen by the user, the controller 50 may be configured to be able to control the pixels in the second division region 17b of the barrier panel 30 as illustrated in
Regardless of the positional relationship between the display panel 20 and the barrier panel 30 as seen from the eyes of the user, it is assumed that the controller 50 is configured to be able to control the pixels in the first division region 17a of the display panel 20 as illustrated in
In the case where the barrier panel 30 is closer to the user than the display panel 20 as seen by the user, the controller 50 may be configured to be able to control the pixels in the second division region 17b of the display panel 20 as illustrated in
In the case where the plurality of black display regions 21B are configured to be removed or shortened in the second division region 17b, the controller 50 may be configured so that the length of the plurality of left-eye image display regions 21L or the plurality of right-eye image display regions 21R is reduced in the third division region 17c further away from the common reference position. In this case, crosstalk is less likely to occur as compared with the case where the plurality of black display regions 21B are continuously shortened.
The controller 50 is configured so that the lengths of the plurality of black display regions 21B reduced by one pixel in the second division region 17b is restored in the third division region 17c, and the controller 50 may be configured so that the plurality of left-eye image display regions 21L and the plurality of right-eye image display regions 21R are shortened by one pixel each. By doing so, the image quality of each of the plurality of left-eye images and the plurality of right-eye images can be maintained evenly.
The controller 50 may be configured so that the length of the plurality of left-eye image display regions 21L or the plurality of right-eye image display regions 21R is shortened in order to shorten the parallax image pitch. By doing so, crosstalk is less likely to occur as compared with the case where the plurality of black display regions 21B are shortened.
When the display panel 20 is located closer to the user than the barrier panel 30 as seen by the user, the controller 50 may be configured to be able to control the pixels in the second division region 17b of the display panel 20 as illustrated in
In the case where the controller 50 is configured so that the plurality of black display regions 21B is lengthened in the second division region 17b, the controller 50 may control such that the length of the plurality of left-eye image display regions 21L or the plurality of right-eye image display regions 21R is increased in the third division region 17c further away from the common reference position. In this case, the image quality of the parallax image is less likely to deteriorate as compared with the case where the plurality of black display regions 21B are continuously lengthened.
In the third division region 17c, the controller 50 may be configured so that the length of the plurality of black display regions 21B increased by one pixel in the second division region 17b is restored, and may be configured so that the plurality of left-eye image display regions 21L and the plurality of right-eye image display regions 21R is lengthened by one pixel each. By doing so, the image quality of each of the plurality of left-eye images and the plurality of right-eye images can be maintained evenly.
The controller 50 may be configured so that the length of the plurality of left-eye image display regions 21L or the plurality of right-eye image display regions 21R is increased in order to increase the parallax image pitch. By doing so, the image quality of the parallax image is less likely to deteriorate as compared with the case where the plurality of black display regions 21B are lengthened.
The arrangement of pixels in the configuration illustrated in
So far, the configuration in the case where the parallax image pitch and the barrier pitch are assumed to be equal has been described. The parallax image pitch and the barrier pitch may be different. In this case, according to the expressions (1) and (2), k>Bp is established in the case where the barrier panel 30 is located closer to the user than the display panel 20 when viewed from the user. In the case where the display panel 20 is located closer to the user than the barrier panel 30 as seen by the user, k<Bp is established. Regardless of the positional relationship between the display panel 20 and the barrier panel 30 as seen by the user, the controller 50 may be configured so that the optimum parallax image pitch and the optimum barrier pitch are discretized. The controller 50 may be configured so that a plurality of division regions 17 can be set in the display panel 20 and the barrier panel 30 based on the discretized optimum parallax image pitch and the optimum barrier pitch.
The controller 50 may be configured so that the division region 17 can be set in the display panel 20 based on the display reference position. In this case, the controller 50 is configured to be able to control the display panel 20 for each division region 17 based on the optimum parallax image pitch associated with the division region 17.
The controller 50 may be configured so that the plurality of division regions 17 can be set in the barrier panel 30 based on the barrier reference position. In this case, the controller 50 is configured to be able to control the barrier panel 30 for each division region 17 based on the optimum barrier pitch associated with the division region 17.
A device according to a comparative example is not configured to set the parallax image pitch based on the display reference position or set the barrier pitch based on the barrier reference position. In this case, the image quality of the parallax image may deteriorate due to the change in the apparent gap. In the image display device 10 according to the embodiment, by configuring at least one of the parallax image pitch and the barrier pitch to be controllable for each division region 17 set based on the reference position, it is possible to improve the image quality of the parallax image in the case where the apparent gap changes.
As illustrated in
The image display system 1 according to the embodiment may be mounted on a moving body. In the case where the image display system 1 is mounted on a moving body, a user of the image display system 1 may be a driver or an operator of the moving body, or a passenger. In the case where the image display system 1 is mounted on a moving body, a part of the configuration of the image display system 1 may be shared with other devices and parts included in the moving body. For example, a windshield of the moving body may also be used as part of the configuration of the image display system 1. For example, the reflective member 60 illustrated in
In the disclosure, examples of the “moving body” include vehicles, ships, and airplanes. In the disclosure, examples of “vehicles” include automobiles and industrial vehicles, but the disclosure is not limited thereto. The examples of “vehicles” may include railway vehicles, daily life vehicles, and fixed-wing aircrafts taxiing on the ground. Examples of automobiles include passenger cars, trucks, buses, motorcycles, and trolley buses, but the disclosure is not limited thereto. Examples of automobiles include other vehicles traveling on roads. Examples of the industrial vehicles include industrial vehicles for agriculture and construction. Examples of the industrial vehicles include forklifts and golf carts, but the disclosure is not limited thereto. Examples of the industrial vehicles for agriculture include tractors, tillers, transplanters, binders, combine harvesters, lawn mowers, but the disclosure is not limited thereto. Examples of the industrial vehicles for construction include bulldozers, scrapers, shovel cars, crane trucks, dump cars, and road rollers, but the disclosure is not limited thereto. Examples of vehicles include things traveling with manpower. The classification of the vehicles is not limited to the above-described vehicles. For example, the automobiles may include industrial vehicles which can travel on roads or may include the same vehicles classified into a plurality of classes. Examples of the ships in the disclosure include marine jets, boats, and tankers. Examples of the airplanes include fixed-wing aircrafts and rotary-wing aircrafts.
The configuration according to the disclosure is not limited to the embodiments described above and can be modified or changed in many ways. For example, the functions and the like included in each component and the like can be rearranged so as not to be logically inconsistent, and a plurality of components and the like can be combined into one or divided.
The diagram illustrating the configuration according to the disclosure is schematic. The dimensional ratios on the drawings do not always match the actual ones.
In the disclosure, the descriptions such as “first” and “second” are identifiers for distinguishing the configuration. The configurations distinguished by the descriptions such as “first” and “second” in the disclosure can exchange numbers in the relevant configurations. For example, the first display region and the second display region can exchange the identifiers “first” and “second”. The exchange of identifiers takes place at the same time. Even after exchanging identifiers, the configuration is distinguished. The identifier may be removed. The configuration with the identifier removed is distinguished by reference numerals and letters. Based solely on the description of identifiers such as “first” and “second” in this disclosure, it shall not be used as a basis for interpreting the order of the configurations or for the existence of identifiers with smaller numbers.
In the disclosure, the X-axis, Y-axis, and Z-axis are provided for convenience of explanation and may be interchanged with each other. The configuration according to the disclosure is described using a Cartesian coordinate system composed of the X-axis, the Y-axis, and the Z-axis. The positional relationship of each configuration according to the disclosure is not limited to being orthogonal.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-205979 | Oct 2018 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2019/041753 | 10/24/2019 | WO | 00 |
