Display device and display method

Abstract

To provide a field sequential display device and display method that do not cause color separation. [Solution] The display device according to the embodiment comprises a light source, a display panel, a detector for detecting the movement speed of the observer's line of sight to an image, and a control means. The control means, when the movement speed is equal to or less than the threshold speed, causes the light source to irradiate with light of one color corresponding to one of the multiple color image signals, and causes the display panel to control the amount of light transmitted to multiple pixels according to the one color image signal, thereby displaying an image of one color at a first saturation. When the movement speed is greater than the threshold speed, the control means causes the light source to irradiate with light of other colors corresponding to other color image signals among the multiple color image signals in addition to the light of one color, and causes the display panel to control the amount of light transmitted to multiple pixels according to the one color image signal, thereby displaying an image of one color at a second saturation lower than the first saturation.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to a field sequential display device and a display method.

Background Art

[0002] There is a field sequential method as one method of color display. In this method, each pixel is driven in a time division manner so as to display a blue image, a green image, or a red image. In synchronization with the display of the blue image, the green image, and the red image, blue display light, green display light, and red display light are lit respectively.

[0003] Eye movement may occur while the user is viewing an image. In this case, color separation (also referred to as Color Brake Up: CBU) may occur due to the shift of the blue image, the green image, and the red image on the retinal image.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Non-Patent Documents

[0005]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] The purpose of this disclosure is to provide a field sequential display device and display method that do not cause color separation. [Means for solving the problem]

[0007] The display device according to this embodiment comprises a light source capable of emitting light of multiple colors, a display panel having multiple pixels capable of controlling the amount of light transmitted and sequentially displaying multiple colored images based on the transmitted light of multiple colors emitted from the light source, a detector for detecting the speed at which the viewer's line of sight moves along the image, and control means. The control means, when the movement speed is not greater than a threshold (equal to or less than the threshold), causes the light source to emit light of one color corresponding to one of the multiple color image signals, causes the display panel to control the amount of light transmitted to multiple pixels according to the one color image signal, and displays an image of one color at a first saturation level. The control means, when the movement speed is greater than a threshold, causes the light source to emit light of one color in addition to light of other colors corresponding to other color image signals among multiple color image signals, and causes the display panel to control the amount of light transmitted to multiple pixels according to one color image signal, thereby displaying an image of one color at a second saturation lower than the first saturation. [Brief explanation of the drawing]

[0008] [Figure 1] A block diagram illustrating an example of a display device according to the first embodiment. [Figure 2] A perspective view illustrating an example of the appearance of a head-mounted display according to the first embodiment. [Figure 3] A diagram illustrating an example of the configuration of a head-mounted display according to the first embodiment. [Figure 4] A cross-sectional view illustrating an example of the configuration of a display unit according to the first embodiment. [Figure 5] A diagram illustrating an example of the configuration of a display panel according to the first embodiment. [Figure 6] A diagram illustrating an example of the configuration of a light source according to the first embodiment. [Figure 7] A diagram illustrating an example of a field sequential method for driving a display panel and light source according to the first embodiment. [Figure 8] A diagram illustrating a first example of preventing color separation in a display device according to the first embodiment. [Figure 9] A flowchart illustrating a first example of color separation prevention according to the first embodiment. [Figure 10] A diagram illustrating a first example of color separation prevention according to the first embodiment. [Figure 11] A diagram illustrating a second example of color separation prevention according to the first embodiment. [Figure 12] A flowchart illustrating a second example of color separation prevention according to the first embodiment. [Figure 13] A diagram illustrating a second example of color separation prevention according to the first embodiment. [Figure 14] A diagram illustrating a second example of a low-saturation light emission pattern according to the first embodiment. [Figure 15] A diagram illustrating a third example of a low-saturation light emission pattern according to the first embodiment. [Figure 16] A diagram illustrating a fourth example of a low-saturation light emission pattern according to the first embodiment. [Modes for carrying out the invention]

[0009] Hereinafter, embodiments will be described with reference to the drawings. The following description exemplifies devices and methods for embodying the technical idea of the embodiments. The technical idea of the embodiments is not limited to the structure, shape, arrangement, material, etc. of the components described below. Modifications that can be easily conceived by those skilled in the art are naturally included in the scope of the disclosure. For the sake of clarity, in the drawings, the size, thickness, planar dimensions, shape, etc. of each element may be changed and schematically represented with respect to the actual element. In a plurality of drawings, there may be elements whose dimensional relationships and ratios to each other are different. In a plurality of drawings, corresponding elements may be assigned the same reference numerals and redundant descriptions may be omitted. Some elements may have multiple designations, but these examples of designations are merely illustrative and do not preclude other designations for these elements. Nor does it preclude other designations for elements that do not have multiple designations. "Connection" may include not only direct connection but also connection through other elements. When the number of elements is not specified as plural, the element may be a single element or a plurality of elements.

[0010] Eye movement is the movement of the eyeball, which is approximately spherical, rotating around the axis of rotation within the orbit. Types of eye movements include the vestibulo-ocular reflex, optokinetic nystagmus, saccadic eye movement, smooth pursuit eye movement, convergence / divergence movement, and fixation microtremor. Among these, the eye movements that cause color separation are saccadic eye movement (also called saccade) and smooth pursuit eye movement (also called Smooth Pursuit Eye Movement: SPEM). SPEM is a low-speed eye movement that smoothly moves the line of sight in accordance with the movement of a visual target. The moving speed of the eyeball as a criterion for distinguishing SPEM from saccades is several tens of degrees per second. For example, an eye movement with a moving speed of 100 degrees per second or more is called a saccade, and an eye movement with a moving speed of less than 100 degrees per second may be called SPEM. Alternatively, an eye movement with a moving speed of 50 degrees per second or more is called a saccade, and an eye movement with a moving speed of less than 50 degrees per second may also be called SPEM. The criterion for distinguishing SPEM from saccades also includes the duration. For example, the duration of a saccade is 100 milliseconds or less (from about 20 milliseconds to about 80 milliseconds), but the duration of SPEM is longer than 100 milliseconds. Hereinafter, saccades are called high-speed eye movements, and SPEM is called low-speed eye movements.

[0011] The first embodiment prevents color separation from occurring due to eye movement.

[0012] FIG. 1 is a block diagram for explaining an example of a display device 1 according to the first embodiment.

[0013] The display device 1 includes a display panel 10, a light source 12, a line-of-sight detector 14, a driver 16, a driver 18, and a controller 20. The display device 1 is a field-sequential display device. The controller 20 is connected to an external host (not shown in FIG. 1). The host supplies a video signal to be displayed on the display device 1 to the controller 20.

[0014] An example of the display panel 10 is a liquid crystal display panel. A driver 16 that drives the display panel 10 is connected to the display panel 10. A light source 12 illuminates the display panel 10. An example of the light source is a light-emitting diode (LED). A driver 18 that drives the light source 12 is connected to the light source 12.

[0015] An example of a gaze detector 14 includes a near-infrared LED, a camera, and a processor. Near-infrared light is shone onto the eyeball, the light reflected from the cornea is captured by the camera, the pupil is detected from the image, and the position of the gaze is determined. Examples of gaze detector types 14 include those in the form of eyeglasses or those embedded in a display panel 10.

[0016] The controller 20 controls the display panel 10 via the driver 16 and the light source 12 via the driver 18, thereby realizing field sequential color display. The controller 20 obtains the position of the gaze from the gaze detector 14 and calculates the speed of the gaze movement.

[0017] The controller 20 detects eye movements by comparing the movement speed with a threshold speed. The controller 20 can detect high-speed eye movements if the threshold speed is set to either 100 degrees / second or 50 degrees / second. If the threshold speed is set to a few degrees / second, the controller 20 can detect eye movements including both high-speed and low-speed eye movements. Upon detecting eye movements, the controller 20 controls drivers 16 and 18 to prevent color separation. Details of color separation prevention will be described later.

[0018] Examples of the display device 1 include flat-panel displays and head-mounted displays. Figure 2 is a perspective view illustrating an example of the appearance of a head-mounted display 26 according to the first embodiment.

[0019] The head-mounted display 26 includes a display unit DSPR for the right eye, a display unit DSPL for the left eye, and a gaze detector 14. When the right-eye display unit DSPR and the left-eye display unit DSPL are not distinguished, they are simply referred to as the display unit DSP. When the user wears the head-mounted display 26 on their head, the display unit DSPR is positioned in front of the user's right eye, and the display unit DSPL is positioned in front of the user's left eye.

[0020] The controller 20, driver 16, and driver 18 are located outside the head-mounted display 26. The head-mounted display 26 may include the controller 20 and drivers 16 and 18. The gaze detector 14 may also be located outside the head-mounted display 26.

[0021] Figure 3 is a diagram illustrating an example of the configuration of a head-mounted display 26 according to the first embodiment.

[0022] The DSPR display unit comprises a display panel 10R, a light source 12R, and an optical system 4R, indicated by a dotted line. The display panel 10R is part of the display panel 10. The light source 12R is part of the light source 12. The light source 12R is located behind the display panel 10R and is configured to illuminate the display panel 10R. The optical system 4R is located in front of the display panel 10R (or between the user's right eye ER and the display panel 10R) and is configured to direct the display light from the display panel 10R to the right eye ER.

[0023] The display panel 10R includes, for example, a liquid crystal panel and a polarizing plate, and is configured to emit linearly polarized display light. The display panel 10R is positioned between the light source 12R and the optical system 4R. The display panel 10R is connected to, for example, a driver IC chip 5R and a flexible printed circuit board 6R. The driver IC chip 5R drives the display panel 10R and controls the display operation of the display panel 10R. The driver IC chip 5R is part of drivers 16 and 18.

[0024] The DSPL display unit comprises a display panel 10L, a light source 12L, and an optical system 4L, indicated by a dotted line. The display panel 10L is part of the display panel 10. The light source 12L is part of the light source 12. The light source 12L is located behind the display panel 10L and is configured to illuminate the display panel 10L. The optical system 4L is located in front of the display panel 10L (or between the user's left eye EL and the display panel 10L) and is configured to direct the display light from the display panel 10L to the left eye EL.

[0025] The display panel 10L includes, for example, a liquid crystal panel and a polarizing plate, and is configured to emit linearly polarized display light. The display panel 10L is positioned between the light source 12L and the optical system 4L. The display panel 10L is connected to, for example, a driver IC chip 5L and a flexible printed circuit board 6L. The driver IC chip 5L drives the display panel 10L and controls the display operation of the display panel 10L. The driver IC chip 5L is part of drivers 16 and 18.

[0026] The DSPL display unit is configured substantially the same as the DSPR display unit. In other words, the display panel 10R, light source 12R, and optical system 4R that make up the DSPR display unit are configured similarly to the display panel 10L, light source 12L, and optical system 4L that make up the DSPL display unit.

[0027] The image displayed on display panel 10L is an image for the left eye (or an image that can be seen by the user's left eye EL). The image displayed on display panel 10R is an image for the right eye (or an image that can be seen by the user's right eye ER).

[0028] One application example of the head-mounted display 26 is virtual reality (VR). When the head-mounted display 26 is used as a display for VR, the image for the left eye and the image for the right eye are similar images that reproduce the parallax between the two eyes. When the image for the left eye displayed on the display panel 10L is viewed by the user's left eye EL, and the image for the right eye displayed on the display panel 10R is viewed by the user's right eye ER, the user can perceive a three-dimensional space as a virtual reality space.

[0029] Figure 4 is a cross-sectional view illustrating an example of the configuration of a display unit DSP according to the first embodiment.

[0030] The display unit DSP comprises a display panel 10, a light source 12, and an optical system 4. The display unit DSP can be applied to display units DSPR and DSPL, respectively. The display panel 10 can be applied to display panels 10R and 2L, respectively. The light source 12 can be applied to light sources 12R and 3L, respectively. The optical system 4 can be applied to optical systems 4R and 4L, respectively.

[0031] The light source 12 comprises a light guide plate LG and a light-emitting element LD. The light-emitting element LD is positioned facing the side surface LGS of the light guide plate LG. The first main surface LGA of the light guide plate LG faces the display panel 10.

[0032] The display panel 10 comprises a first substrate SUB1, a second substrate SUB2, a first liquid crystal layer LC1, a first polarizer PL1, and a second polarizer PL2. The first liquid crystal layer LC1 is sealed between the first substrate SUB1 and the second substrate SUB2 by a seal SE1. The first polarizer PL1 is located between the first substrate SUB1 and the light source 12 (or light guide plate LG). The second polarizer PL2 is located between the second substrate SUB2 and the optical system 4 (or first phase difference plate R1).

[0033] The display panel 10 is configured to achieve so-called normally white, by transmitting ambient light that has passed through the light guide plate LG when no electric field is formed in the first liquid crystal layer LC1.

[0034] Illumination light emitted from the light-emitting element LD of the light source 12 propagates through the light guide plate LG and illuminates the display panel 10. In the display panel 10, some of the linearly polarized illumination light passes through the first polarizer plate PL1 and is selectively modulated in the first liquid crystal layer LC1. Some of the light modulated in the first liquid crystal layer LC1 passes through the second polarizer plate PL2 and is emitted as display light DL. Display light DL is linearly polarized parallel to the transmission axis of the second polarizer plate PL2.

[0035] The optical system 4 comprises a first structure 4A and a second structure 4B. The first structure 4A is spaced apart from the second structure 4B. In the example shown in Figure 4, an air layer 4C is interposed between the first structure 4A and the second structure 4B. The first structure 4A is located between the display panel 10 and the second structure 4B (or the air layer 4C). A transparent medium may be interposed between the first structure 4A and the second structure 4B instead of the air layer 4C.

[0036] The first structure 4A comprises a first phase difference plate R1, a holographic optical element HE, and a second phase difference plate R2. The first phase difference plate R1 faces the display panel 10 (or the second polarizer PL2). The holographic optical element HE faces the first phase difference plate R1. The second phase difference plate R2 faces the holographic optical element HE. The holographic optical element HE is located between the first phase difference plate R1 and the second phase difference plate R2.

[0037] The first phase difference plate R1 and the second phase difference plate R2 are quarter-wave plates and are configured to impart a quarter-wave retardation to the transmitted light.

[0038] A holographic optical element HE has an interference fringe pattern and a refractive index component in the thickness direction with a period corresponding to the wavelength. Such a holographic optical element HE is configured to reflect and diffract a portion of the incident light and has substantially the same function as a concave mirror.

[0039] The second structure 4B comprises a polarization conversion element PE and a reflective polarizer PR. The polarization conversion element PE is located between the second phase difference plate R2 (or air layer 4C) and the reflective polarizer PR. The second phase difference plate R2, the air layer 4C, and the polarization conversion element PE are interposed between the reflective polarizer PR and the holographic optical element HE.

[0040] The polarization conversion element PE is, for example, a liquid crystal element and comprises a third substrate SUB3, a fourth substrate SUB4, and a second liquid crystal layer LC2. The second liquid crystal layer LC2 is sealed between the third substrate SUB3 and the fourth substrate SUB4 by a seal SE2. In the illustrated example, the third substrate SUB3 faces the second phase difference plate R2 via an air layer 4C, and the fourth substrate SUB4 faces the reflective polarizer PR. The second liquid crystal layer LC2 contains twist-oriented liquid crystal molecules, which will be described later.

[0041] The polarization conversion element PE is configured to have a no-conversion mode that maintains the polarization direction of the linearly polarized light DL, which is the display light, and a conversion mode that rotates the polarization direction of the linearly polarized light, which is the ambient light transmitted through the light guide plate LG. An example of a polarization conversion element PE is a twisted nematic (TN) liquid crystal element. However, an element other than a TN liquid crystal element may be used as the polarization conversion element PE as long as it is configured to be switchable between the no-conversion mode and the conversion mode.

[0042] The reflective polarizer PR is configured to transmit the first linearly polarized light and reflect the second linearly polarized light that is orthogonal to the first linearly polarized light.

[0043] The polarization conversion element PE may be provided in the first structure 4A. The second phase difference plate R2 may be provided in the second structure 4B.

[0044] The controller 20 is configured to control drivers 16, 18, and 30.

[0045] The driver 16 drives the display panel 10 and switches between display mode and transmission mode. In display mode, the driver 16 selectively forms an electric field in the first liquid crystal layer LC1 to display an image. In transmission mode, the driver 16 does not form an electric field in the first liquid crystal layer LC1 and transmits ambient light through the display panel 10 without displaying an image.

[0046] The driver 18 drives the light source 12 and switches between an on mode synchronized with the display mode and an off mode synchronized with the translucent mode.

[0047] The driver 30 drives the polarization conversion element PE and switches between a no-conversion mode synchronized with the display mode and a conversion mode synchronized with the transmission mode.

[0048] Figure 5 is a diagram illustrating an example of the configuration of the display panel 10 (Figure 4) according to the first embodiment.

[0049] The display panel 10 has a display area DA for displaying an image. The display area DA has a plurality of pixels PX arranged in a matrix.

[0050] The display panel 10 includes, in the display area DA, a plurality of scan lines GL, a plurality of signal lines SL, a switching element SW and a first transparent electrode TE1 arranged on each pixel PX, and a second transparent electrode TE2 arranged across the plurality of pixels PX. The plurality of scan lines GL and the plurality of signal lines SL intersect with each other. The switching element SW is electrically connected to either scan line GL and either signal line SL. The first transparent electrode TE1 corresponds to a pixel electrode electrically connected to the switching element SW. The second transparent electrode TE2 corresponds to a common electrode facing the plurality of first transparent electrodes TE1.

[0051] The scan line GL, signal line SL, switching element SW, and first transparent electrode TE1 are provided on the first substrate SUB1 (Figure 4). The second transparent electrode TE2 is provided on the first substrate SUB1, but may also be provided on the second substrate SUB2. At each pixel PX, an electric field is formed in the first liquid crystal layer LC1 due to the potential difference between the first transparent electrode TE1 and the second transparent electrode TE2.

[0052] The driver 16 includes a gate driver 32 that supplies a scanning signal to the scan line GL and a display driver 34 that supplies a video signal to the signal line SL.

[0053] Figure 6 is a diagram illustrating an example of the configuration of the light source 12 (Figure 4) according to the first embodiment.

[0054] The light source 12 comprises a light guide plate LG and a plurality of light-emitting elements LD. The plurality of light-emitting elements LD are facing the side surface LGS of the light guide plate LG. The plurality of light-emitting elements LD include a light-emitting element LDB configured to emit blue wavelength (first wavelength) light, a light-emitting element LDG configured to emit green wavelength (second wavelength) light, and a light-emitting element LDR configured to emit red wavelength (third wavelength) light. The light-emitting elements LDB, LDG, and LDR are spaced apart. These light-emitting elements LD are driven by a driver 18.

[0055] The light emitted from the light-emitting element LD may be light with a narrow spectral width (or high color purity). In this case, a laser light source may be used as the light-emitting element LD. The central wavelength of the blue laser light emitted from the light-emitting element LDB is represented by λb, the central wavelength of the green laser light emitted from the light-emitting element LDG is represented by λg, and the central wavelength of the red laser light emitted from the light-emitting element LDR is represented by λr. The holographic optical element HE shown in Figure 4 is optimized to reflect light with central wavelengths λb, λg, and λr, respectively.

[0056] Figure 7 is a diagram illustrating an example of a driving method for the display panel 10 and light source 12 using a field sequential method according to the first embodiment.

[0057] Driver 16 drives each pixel PX in a time-division manner. Driver 18 sequentially drives the light-emitting element LDB, light-emitting element LDG, and light-emitting element LDR. Controller 20 controls drivers 16 and 18 to synchronize the timing of each light-emitting element lighting up with the timing of writing the video signal of the color of the lit light-emitting element to the pixel PX.

[0058] Each frame displaying an image includes a first subframe displaying a blue image, a second subframe displaying a green image, and a third subframe displaying a red image.

[0059] In the first subframe, a blue image signal corresponding to the blue image is written to pixel PX, the light-emitting element LDB lights up, and the other light-emitting elements LDG and LDR turn off. As a result, blue display light DLB is emitted from the display panel 10. In the second subframe, a green image signal corresponding to the green image is written to pixel PX, the light-emitting element LDG lights up, and the other light-emitting elements LDB and LDR turn off. As a result, green display light DLG is emitted from the display panel 10. In the third subframe, a red image signal corresponding to the red image is written to pixel PX, the light-emitting element LDR lights up, and the other light-emitting elements LDG and LDB turn off. As a result, red display light DLR is emitted from the display panel 10.

[0060] By applying this field sequential method, a color image can be displayed on the display panel 10, which does not have a color filter. Compared to a color filter method in which each pixel PX has a color filter, the field sequential method does not have unwanted light absorption by the color filter, and the transmittance of the display panel 10 can be improved.

[0061] Figure 8 is a diagram illustrating a first example of color separation prevention in the display device 1 according to the first embodiment. The color separation prevention mechanism comprises a gaze detector 14, a controller 20, and a head-mounted display 26. The gaze detector 14 may be integrated with the head-mounted display 26. A general flat-panel display or the like may be used instead of the head-mounted display 26.

[0062] The head-mounted display 26 includes display panels 10R, 10L, light sources 12R, 12L, and drivers 16, 18.

[0063] The controller 20 includes an eye movement detector 42 and a rendering unit 44. A video signal is supplied from the host to the rendering unit 44. The video signal includes a blue image signal, a green image signal, and a red image signal.

[0064] The eye movement detector 42 is connected to the gaze detector 14. The eye movement detector 42 acquires the gaze position detected by the gaze detector 14 and calculates the gaze movement speed and direction based on the change in the gaze position. If the movement speed is greater than the threshold speed, the eye movement detector 42 detects eye movement. The eye movement detector 42 outputs an eye movement determination signal indicating whether or not eye movement has been detected, and a gaze movement signal indicating the gaze movement speed and direction, to the rendering unit 44.

[0065] A single frame of color image consists of multiple color images (e.g., blue, green, red). When the gaze moves during the display period of these multiple color images, the positions of the multiple color images on the retina shift, causing color separation. To prevent color separation, the display positions of the color images on the retina should be shifted to counteract the movement of the gaze. Since the multiple pixel signals that make up the color image signal each correspond to a predetermined pixel, the rendering unit 44 can shift the display position of the color image on the retina from its predetermined position by making the image output to the driver 16 correspond to pixels shifted by a few pixels from the predetermined pixels. For example, if the gaze moves to the right by P pixels / microseconds, the rendering unit 44 generates a corrected color image signal in which all pixels correspond to pixels shifted P pixels to the right from the predetermined pixels. This pixel shifting process may also be implemented in the driver 16 and controlled by commands from the rendering unit 44.

[0066] When the driver 16 performs color separation correction processing, the rendering unit 44 outputs a color image signal to the driver 16 if the eye movement detection signal indicates that no eye movement has been detected. In this case, the driver 16 drives a predetermined pixel according to the color image signal. If the eye movement detection signal indicates that eye movement has been detected, the rendering unit 44 calculates a corrected color image signal that shifts the correspondence between pixel signals and pixels from the predetermined relationship according to the speed and direction of gaze movement. If the eye movement detection signal indicates that eye movement has been detected, the rendering unit 44 outputs the corrected color image signal to the driver 16. The driver 16 drives a pixel that has shifted from the predetermined pixel according to the corrected color image signal.

[0067] The corrected color image signal calculated by the rendering unit 44 is the corrected color image signal for a given frame. The display position is changed by this corrected color image signal for frames following a given frame. Therefore, simply changing the display position of the image may not be sufficient to prevent color separation.

[0068] It is known that perceptual information on the retina decreases during eye movements, making it difficult to recognize changes in the displayed image before and after eye movements. Furthermore, perceptual information during eye movements is more sensitive to saturation than to brightness. That is, changes in brightness are difficult to recognize during eye movements, but changes in saturation are easily recognized. This is particularly pronounced when eye movements are fast. Therefore, if eye movements are detected, reducing the saturation of the displayed image makes color separation difficult to perceive. The color separation prevention according to this embodiment includes reducing the saturation of the displayed image. Reducing saturation includes reducing the saturation of a color image and changing the color display to a monochrome display.

[0069] The rendering unit 44 outputs an eye movement detection signal to the driver 18. When the eye movement detection signal indicates the detection of eye movement, the driver 18 changes the emission pattern of the light source 12 and reduces the saturation of the displayed image.

[0070] The controller 20 may include two hardware blocks that implement the eye movement detector 42 and the rendering 44, respectively. Alternatively, the controller 20 may include one or more CPUs. One or more CPUs implement the functions of the eye movement detector 42 and the rendering 44 by executing a program.

[0071] Figure 9 is a flowchart illustrating a first example of color separation prevention according to the first embodiment shown in Figure 8.

[0072] The eye movement detector 42 obtains the gaze position from the gaze detection detector 14 (step S12). The eye movement detector 42 calculates the gaze movement speed from the change in gaze position (step S14). The eye movement detector 42 determines whether the gaze movement speed is greater than the threshold speed (step S16).

[0073] If the speed of gaze movement is greater than the threshold speed, i.e., if eye movement is detected (Yes in step S16), the eye movement detector 42 outputs an eye movement determination signal and a gaze movement signal to the rendering unit 44 (step S18).

[0074] The rendering unit 44 calculates a corrected color image signal in which the correspondence between pixel signals and pixels is shifted from the default relationship according to the gaze movement signal. The rendering unit 44 outputs the corrected color image signal to the driver 16 (step S20).

[0075] The driver 16 drives the pixels according to the corrected color image signal (step S22).

[0076] The rendering unit 44 outputs an eye movement detection signal to the driver 18 (step S24).

[0077] If the eye movement detection signal indicates that eye movement has been detected, the driver 18 changes the light emission pattern of the light source 12 from a default field sequential light emission pattern to a low-saturation light emission pattern, thereby reducing the saturation of the displayed image (step S26).

[0078] If the speed of eye movement is not greater than the threshold speed (i.e., equal to or less than the threshold speed), i.e., if no eye movement is detected (No. in step S16), the eye movement detector 42 outputs an eye movement determination signal to the rendering unit 44 (step S28).

[0079] The rendering unit 44 outputs a color image signal to the driver 16 (step S30). The driver 16 drives the pixels according to the color image signal (step S32). The display position of the displayed image is the default position.

[0080] The rendering unit 44 outputs a color image signal and an eye movement detection signal to the driver 18 (step S34). If the eye movement detection signal indicates that no eye movement has been detected, the driver 18 sets the light emission pattern of the light source 12 to a default field sequential light emission pattern and displays the image with a default saturation (step S36).

[0081] Figure 10 is a diagram illustrating a first example of color separation prevention according to the first embodiment shown in Figures 8 and 9. The horizontal axis in Figure 10 represents time. Assume that eye movement begins at time t1 and the eye movement detector 42 detects eye movement at time t2. Assume that time t2 is after the rendering of frame N and before the rendering of frame (N+1).

[0082] Prior to the eye movement detection time t2, the driver 18 drives the light source 12 in a predetermined field sequential emission pattern. That is, the driver 18 lights up the light-emitting elements LDB, LDG, and LDR for a certain period in each subframe. The driver 16 drives predetermined pixels according to the color image signal. The light source 12 lights up the display panel 10 for a certain period in each subframe with blue, green, or red indicator light. The display panel 10 displays a blue image, a green image, or a red image in the subframes where the blue, green, or red indicator light is lit. The display image (color image) of one frame, consisting of three subframe periods of the blue, green, and red images, is displayed with a first saturation corresponding to the certain period during which the blue, green, and red indicator light is lit. From the eye movement start time t1 up to frame N, color separation is recognized in the display images of each frame, where the positions of the blue, green, and red images are shifted relative to each other.

[0083] When the eye movement detector 42 detects eye movement at time t2, the eye movement detector 42 outputs an eye movement determination signal to the rendering unit 44. Subsequently, the rendering unit 44 outputs the eye movement determination signal to the driver 18. Upon receiving the eye movement determination signal, the driver 18 drives the light source 12 with a low-saturation emission pattern. Since the eye movement determination signal is supplied to the driver 18 via the rendering unit 44, there is a delay between time t2 when the eye movement detector 42 detects eye movement and the timing when the driver 18 switches the light emission pattern of the light source 12 from the default emission pattern to the low-saturation emission pattern. In the example in Figure 10, after the blue display light of frame (N+1) is emitted, the driver 18 drives the light source 12 with a low-saturation emission pattern.

[0084] In the low-saturation illumination pattern, the light-emitting elements LDB, LDG, and LDR are illuminated simultaneously in each subframe. The simultaneous illumination period is 1 / 3 of the illumination time of the blue, green, or red indicator light in one subframe of the default illumination pattern using the field sequential method. Therefore, the brightness of the displayed image does not change before and after time t2, but the saturation decreases. Because the light-emitting elements LDB, LDG, and LDR are illuminated simultaneously, the displayed image of frame (N+1) and subsequent frames becomes a monochrome image (achromatic). Therefore, when eye movement is detected, the saturation of the displayed image decreases, making color separation difficult to perceive.

[0085] Figure 11 is a diagram illustrating a second example of color separation prevention according to the first embodiment. In the first example shown in Figure 8, the eye movement detector 42 outputs an eye movement detection signal and a gaze movement signal to the rendering unit 44. The rendering unit 44 outputs the eye movement detection signal to the driver 18. In the second example shown in Figure 11, the eye movement detector 42 outputs the eye movement detection signal and the gaze movement signal to the rendering unit 44, and also outputs the eye movement detection signal to the driver 18.

[0086] Figure 12 is a flowchart illustrating a second example of color separation prevention according to the first embodiment shown in Figure 11. Processes in Figure 12 that are the same as those in Figure 9 are given the same step numbers as in Figure 9, and their explanations are omitted.

[0087] In step S18B of Figure 12, which corresponds to step S18 of Figure 8, the eye movement detector 42 outputs the eye movement detection signal and the gaze movement signal to the rendering unit 44, and outputs the eye movement detection signal to the driver 18. Since the eye movement detector 42 outputs the eye movement detection signal to the driver 18 in step S18B, step S24 of Figure 8, in which the eye movement detection signal is output to the driver 18, is omitted in Figure 12.

[0088] Figure 13 is a diagram illustrating a second example of color separation prevention according to the first embodiment shown in Figures 11 and 12. Figure 13 corresponds to Figure 10. According to the second example, in step S18B of Figure 12, the eye movement detector 42 outputs an eye movement determination signal to the driver 18, so the timing at which the driver 18 changes the light emission pattern of the light source 12 from a predetermined light emission pattern using a field sequential method to a light emission pattern for low saturation in response to the eye movement determination signal becomes earlier compared to the first example shown in Figure 10. In the example of Figure 13, after the red display light of frame (N-1) is emitted, the driver 18 drives the light source 12 with a light emission pattern for low saturation. Therefore, according to the second example, the time from the detection time t2 of eye movement to the start of frame N displaying a low-saturation image is shortened compared to the first example shown in Figure 10.

[0089] In the above description, the driver 16 drives the pixels of the display panel 10 according to the color image even after detecting eye movement. However, after detecting eye movement, the driver 16 may drive the pixels of the display panel 10 according to a monochrome image (for example, a green image signal) instead of a color image.

[0090] Other examples of low-saturation light emission patterns according to the first embodiment are described below. The following description describes the light emission pattern in the configuration example shown in Figure 11. However, the following light emission patterns are also applicable to the configuration example shown in Figure 8.

[0091] The first example of a low-saturation emission pattern is an emission pattern that reduces saturation by displaying a monochrome image. The second example of a low-saturation emission pattern is an emission pattern that reduces the saturation of a color image. Figure 14 is a diagram illustrating the second example of a low-saturation emission pattern according to the first embodiment. Figure 14 corresponds to Figure 13.

[0092] In the first example of the low-saturation light emission pattern shown in Figure 13, the driver 18 illuminates the light-emitting element LDB, light-emitting element LDG, and light-emitting element LDR evenly in each subframe. In the second example shown in Figure 14, the light-emitting element LDB, light-emitting element LDG, and light-emitting element LDR are illuminated simultaneously in each subframe, but the illumination periods of the three elements are not equal. Any two illumination periods are equal to each other, but the remaining illumination period is longer than the other two. The sum of the three illumination periods of one subfield in the low-saturation light emission pattern is equal to the illumination time of the blue, green, or red indicator light in one subframe in the default light emission pattern using the field sequential method.

[0093] A single color image in a field sequential system consists of a blue image, a green image, and a red image, and one frame consists of a subframe of blue display light, a subframe of green display light, and a subframe of the red image. In the second example of the low-saturation emission pattern, in the subframe of blue display light, the illumination periods of the green display light and the red display light are equal, and the illumination period of blue display light is longer than that of green display light and red display light. In the subframe of green display light, the illumination periods of blue display light and red display light are equal, and the illumination period of green display light is longer than that of blue display light and red display light. In the subframe of red display light, the illumination periods of blue display light and green display light are equal, and the illumination period of red display light is longer than that of blue display light and green display light.

[0094] Therefore, until eye movement is detected, a color image with the first saturation level is displayed, and once eye movement is detected, a color image with a lower saturation level than the first saturation level is displayed.

[0095] Figure 15 is a diagram illustrating a third example of a low-saturation light emission pattern according to the first embodiment. The third example is a light emission pattern that reduces saturation by displaying a monochrome image. Figure 15 corresponds to Figure 13.

[0096] In the first example of the low-saturation light emission pattern shown in Figure 13, the driver 18 evenly illuminates the light-emitting element LDB, LDG, and LDR in each subframe. In the third example shown in Figure 15, the light-emitting element LDB, LDG, and LDR are also illuminated simultaneously in each subframe, but the simultaneous illumination periods differ in each subframe.

[0097] In the blue indicator light subframe, three indicator lights illuminate simultaneously during period d1. In the green indicator light subframe, three indicator lights illuminate simultaneously during period d2. In the red indicator light subframe, three indicator lights illuminate simultaneously during period d3. d1 is shorter than d2 and d3. d2 is longer than d3. d3 is longer than d1. That is, d1 <d3<d2である。

[0098] The total illumination time for each color indicator light in one frame is equal to the illumination time of the blue, green, or red indicator light in one subframe in a predetermined illumination pattern using the field sequential method.

[0099] The ratios of d1, d2, and d3 are set according to human perceptual characteristics. Human color perception sensitivity is such that, if the sensitivity to blue is 1, the sensitivity to red is approximately 3, and the sensitivity to green is approximately 6. Therefore, d1:d2:d3 is approximately 1:6:3.

[0100] In the third example, a color image with the first saturation level is displayed until eye movement is detected, and once eye movement is detected, a monochrome image with a lower saturation level than the first saturation level is displayed.

[0101] Figure 16 is a diagram illustrating a fourth example of a low-saturation light emission pattern according to the first embodiment. The fourth example is a light emission pattern that reduces saturation by displaying a monochrome image. Figure 16 corresponds to Figure 13.

[0102] In the first example of the low-saturation light emission pattern shown in Figure 13, the driver 18 evenly illuminates the light-emitting element LDB, LDG, and LDR in each subframe. In the fourth example shown in Figure 16, the light-emitting element LDB, LDG, and LDR are simultaneously illuminated in only one of the three subframes that make up one frame (for example, the subframe that displays blue indicator light). The simultaneous illumination time is equal to the illumination time of the blue indicator light, green indicator light, or red indicator light in one subframe in the default light emission pattern using the field sequential method. Therefore, the total illumination time of the blue indicator light, green indicator light, and red indicator light in one frame is the same for both the default light emission pattern using the field sequential method and the low-saturation light emission pattern.

[0103] This disclosure is not limited to the embodiments described above, and the components can be modified and implemented in practice without departing from the gist of the invention. Furthermore, various disclosures can be formed by appropriately combining the multiple components disclosed in the embodiments. For example, some components may be deleted from all the components shown in the embodiments. Moreover, components from different embodiments may be combined as appropriate. [Explanation of symbols]

[0104] 10…Display panel, 12…Light source, 14…Eye-tracking detector, 16, 18…Driver, 20…Controller

Claims

1. A light source capable of emitting light of multiple colors, A display panel having multiple pixels capable of controlling the amount of light transmitted, which sequentially displays multiple colored images based on the transmitted light of multiple lights irradiated from the light source, A detector that detects the speed of movement of the observer's line of sight in the aforementioned image, Control means that, when the moving speed is equal to or less than the threshold speed, the light source is irradiated with light of one color corresponding to one of the multiple color image signals, the amount of light transmitted to the multiple pixels on the display panel is controlled according to the one color image signal, and the image of the one color is displayed at a first saturation; and when the moving speed is greater than the threshold speed, the light source is irradiated with light of other colors corresponding to other color image signals among the multiple color image signals in addition to the light of the one color, the amount of light transmitted to the multiple pixels on the display panel is controlled according to the one color image signal, and the image of the one color is displayed at a second saturation lower than the first saturation, A display device equipped with the following.

2. The control means is If the aforementioned moving speed is not greater than the threshold speed, the display panel displays the image of one color at a first display position corresponding to the one color image signal. The display device according to claim 1, wherein if the moving speed is greater than the threshold speed, a second display position is determined by correcting the first display position according to the moving speed, and the image of the one color is displayed on the display panel at the second display position.

3. If the aforementioned moving speed is equal to or less than the aforementioned threshold speed, the control means: During the first period, the light source is irradiated with a first light corresponding to a first color image signal at a first light intensity. In the second period following the first period, the light source is irradiated with a second light corresponding to the second color image signal at the first light intensity. In the third period following the second period, the light source is irradiated with a third light corresponding to the third color image signal at the first light intensity. If the aforementioned moving speed is greater than the aforementioned threshold speed, the control means, During the fourth period, the fifth period following the fourth period, and the sixth period following the fifth period, the light source is irradiated with the first light, the second light, and the third light. During the fourth period, the amount of light from the first light was greater than the amount of light from the second light, and greater than the amount of light from the third light. During the fifth period, the amount of light from the second light was greater than the amount of light from the first light, and greater than the amount of light from the third light. The display device according to claim 1, wherein in the sixth period, the amount of light of the third light is greater than the amount of light of the first light and greater than the amount of light of the second light.

4. The display device according to claim 3, wherein in the fourth, fifth, and sixth periods, the sum of the light intensity of the first light, the light intensity of the second light, and the light intensity of the third light is equal to the light intensity of the first light.

5. If the aforementioned moving speed is equal to or less than the aforementioned threshold speed, the control means: During the first period, the light source is irradiated with a first light corresponding to a first color image signal at a first light intensity. In the second period following the first period, the light source is irradiated with a second light corresponding to the second color image signal at the first light intensity. In the third period following the second period, the light source is irradiated with a third light corresponding to the third color image signal at the first light intensity. If the aforementioned moving speed is greater than the aforementioned threshold speed, the control means, During the fourth period, the light source is irradiated with the first light at a second intensity, the second light at a second intensity, and the third light at a second intensity. In the fifth period following the fourth period, the light source is irradiated with the first light at a third intensity, the second light at a third intensity, and the third light at a third intensity. The display device according to claim 1, wherein in a sixth period following the fifth period, the light source is irradiated with the first light at a fourth intensity, the second light at a fourth intensity, and the third light at a fourth intensity.

6. The display device according to claim 5, wherein the relative ratio of the second light intensity, the third light intensity, and the fourth light intensity is proportional to the human visibility of the first light, the second light, and the third light.

7. If the aforementioned moving speed is equal to or less than the aforementioned threshold speed, the control means: During the first period, the light source is irradiated with a first light corresponding to a first color image signal at a first light intensity. In the second period following the first period, the light source is irradiated with a second light corresponding to the second color image signal at the first light intensity. In the third period following the second period, the light source is irradiated with a third light corresponding to the third color image signal at the first light intensity. If the aforementioned moving speed is greater than the aforementioned threshold speed, the control means, During the fourth period, the light source is irradiated with the first light, the second light, and the third light at a second light intensity. In the fifth period following the fourth period, the light source is irradiated with the first light, the second light, and the third light at a second light intensity. The display device according to claim 1, wherein in a sixth period following the fifth period, the light source is irradiated with the first light, the second light, and the third light at a second light intensity.

8. The display device according to claim 7, wherein the second light quantity is one-third of the first light quantity.

9. If the aforementioned moving speed is equal to or less than the aforementioned threshold speed, the control means: During the first period, the light source is irradiated with a first light corresponding to a first color image signal at a first light intensity. In the second period following the first period, the light source is irradiated with a second light corresponding to the second color image signal at the first light intensity. In the third period following the second period, the light source is irradiated with a third light corresponding to the third color image signal at the first light intensity. If the aforementioned moving speed is greater than the aforementioned threshold speed, the control means, During the fourth period, the fifth period following the fourth period, and the sixth period following the fifth period, the light source is irradiated with the first light at a second intensity, the second light at a second intensity, and the third light at a second intensity. The display device according to claim 1, wherein the light source is not irradiated with the first light, the second light, and the third light during the other two periods of the fourth period, the fifth period, and the sixth period.

10. The display device according to claim 9, wherein the second light quantity is equal to the first light quantity.

11. The display device according to any one of claims 1 to 10, wherein the threshold velocity is 50 degrees per second or 100 degrees per second.

12. A light source capable of emitting light of multiple colors, A display panel having multiple pixels capable of controlling the amount of light transmitted, which sequentially displays multiple colored images based on the transmitted light of multiple lights irradiated from the light source, A display method for a display device comprising a detector that detects the speed of movement of the observer's line of sight in the aforementioned image, When the aforementioned moving speed is equal to or less than the threshold speed, the light source is irradiated with light of one color corresponding to one of the multiple color image signals, the amount of light transmitted to the multiple pixels on the display panel is controlled according to the one color image signal, and the image of the one color is displayed with a first saturation. A display method in which, when the moving speed is greater than the threshold speed, the light source is irradiated with light of the other color corresponding to the other color image signals among the plurality of color image signals in addition to the light of the one color, the display panel controls the amount of light transmitted to the plurality of pixels according to the one color image signal, and the image of the one color is displayed with a second saturation lower than the first saturation.

Images