Stereoscopic image display apparatus

Abstract

To provide a stereoscopic image display device capable of controlling average luminance of pixels in a display period without depending on a position in a line sequential direction.SOLUTION: A stereoscopic image display device 10 includes a liquid crystal display panel 22, a variable focus lens unit 40, and a control unit 80. The liquid crystal display panel 22 displays the first image and the second image that are sequentially displayed by the line sequential scanning, and emits the display light PL1 of the first image and the display light PL1 of the second image. The variable focus lens unit 40 switches the focal distance with respect to the display light PL1, and forms the first image and the second image as virtual images on the first display surface 102 and the second display surface 104, respectively. The control unit 80 forms a display period for displaying each of the first image and the second image from a plurality of frame periods, and controls the luminance of the pixels of the liquid crystal display panel to the minimum luminance of the pixels in the last frame period of the plurality of frame periods forming the display period.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a stereoscopic image display device. [Background technology]

[0002] Depth Fused 3D (DFD) stereoscopic image display devices are known as display devices that display stereoscopic images (three-dimensional images) that are visible to the naked eye. For example, Patent Document 1 discloses a three-dimensional display device that includes a display device that alternately displays two two-dimensional images, a polarizing plate that outputs light emitted from the display device as polarized light, a polarization switching device that switches the polarization direction of the light emitted from the polarizing plate, and a polarized bifocal lens.

[0003] In the three-dimensional display device of Patent Document 1, two two-dimensional images are alternately formed on display surfaces located at different depth positions from the observer, and the brightness or transparency of the two two-dimensional images is changed independently to display a three-dimensional image. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-129983 Summary of the Invention [Problem to be solved by the invention]

[0005] When the three-dimensional display device of Patent Document 1 uses a display device that performs display operation continuously over one frame period by line-sequential scanning, such as a liquid crystal display device or an organic EL (Electro Luminescence) display device, the luminance of the pixels (the luminance of the pixels forming the two-dimensional image) perceived by the viewer is the luminance obtained by averaging the luminance of the pixels of the display device over one frame period. In this case, for pixels located on the start side of the line-sequential scanning, the luminance perceived by the viewer and the luminance of the display device are approximately equal. On the other hand, for pixels located on the end side of the line-sequential scanning, the time during which display light is emitted according to an image signal within one frame period is short, so the luminance perceived by the viewer is significantly different from the luminance of the display device.

[0006] That is, since pixel signals (pixel data) are rewritten at different times within one frame period depending on the position in the line sequential direction of the display device (two-dimensional image), even if the luminance of the pixels on the display device is the same, the luminance perceived by the viewer (luminance obtained by averaging the luminance of the pixels on the display device over one frame period) will differ depending on the position in the line sequential direction of the display device. In the three-dimensional display device of Patent Document 1, if pixels of the same luminance on the display device are perceived by the viewer as pixels of different luminance depending on the position in the line sequential direction of the display device, the viewer will perceive a three-dimensional image with a different shape from the three-dimensional image that should be displayed.

[0007] The present disclosure has been made in consideration of the above circumstances, and aims to provide a stereoscopic image display device that can control the average luminance of pixels during a display period, regardless of their position in the line-sequential direction. [Means for solving the problem]

[0008] In order to achieve the above object, a stereoscopic image display device according to a first aspect of the present disclosure comprises: a liquid crystal display panel that sequentially displays a first image and a second image and emits display light for the first image and display light for the second image; a variable-focus lens unit that switches between a focal length for displaying the first image and a focal length for displaying the second image; a control unit that controls the display of the liquid crystal display panel, the first image and the second image are two-dimensional images of a display object projected from a side of the observer onto a first display surface and a second display surface that are located at different positions in a depth direction as seen from the observer, respectively; the liquid crystal display panel displays the first image and the second image by line-sequential scanning; the variable-focus lens unit forms the first image and the second image as virtual images on the first display surface and the second display surface, respectively; The control unit forming a display period for displaying each of the first image and the second image from a plurality of frame periods; In the last frame period among the plurality of frame periods that form the display period, the luminance of the pixel of the liquid crystal display panel is controlled to the minimum luminance of the pixel.

[0009] A stereoscopic image display device according to a second aspect of the present disclosure includes: a self-luminous display panel that sequentially displays a first image and a second image and emits display light for the first image and display light for the second image; a variable-focus lens unit that switches between a focal length for displaying the first image and a focal length for displaying the second image; a control unit that controls the display of the self-luminous display panel, the first image and the second image are two-dimensional images of a display object projected from a side of the observer onto a first display surface and a second display surface that are located at different positions in a depth direction as seen from the observer, respectively; the self-luminous display panel displays the first image and the second image by line-sequential scanning; the variable-focus lens unit forms the first image and the second image as virtual images on the first display surface and the second display surface, respectively; The control unit forming a display period for displaying each of the first image and the second image from a plurality of frame periods; In the last frame period of the plurality of frame periods that form the display period, the luminance of the pixel of the self-luminous display panel is controlled to the minimum luminance of the pixel. [Effects of the Invention]

[0010] According to the present disclosure, the display period for displaying each of the first and second images is formed from multiple frame periods, and the brightness of the pixel in the last frame period is controlled to the minimum brightness of the pixel, so that the average brightness of the pixel in the display period can be controlled regardless of its position in the line sequential direction. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram showing a stereoscopic image display device according to a first embodiment. [Figure 2] 1 is a plan view showing a liquid crystal display panel according to Embodiment 1. FIG. [Figure 3] 1 is a cross-sectional view showing a polarization switching section according to a first embodiment. [Figure 4] 1 is a cross-sectional view showing a polarized bifocal lens according to embodiment 1. [Figure 5] FIG. 2 is a block diagram showing a control unit according to the first embodiment. [Figure 6] FIG. 2 is a diagram illustrating a hardware configuration of a control unit according to the first embodiment. [Figure 7] FIG. 2 is a diagram showing a first image according to the first embodiment. [Figure 8] FIG. 4 is a diagram showing a second image according to the first embodiment. [Figure 9] 5A and 5B are diagrams for explaining display control of a liquid crystal display panel and control of a polarization switching unit according to the first embodiment. [Figure 10] 10A and 10B are diagrams for explaining a display operation of a liquid crystal display panel according to a comparative example. [Figure 11] FIG. 10 is a diagram showing a first image to be recognized according to a comparative example. [Figure 12] FIG. 10 is a diagram showing a second image to be recognized according to a comparative example. [Figure 13]FIG. 10 is a diagram illustrating display control of a liquid crystal display panel according to a second embodiment. [Figure 14] FIG. 10 is a diagram for explaining display control of a liquid crystal display panel according to a third embodiment. [Figure 15] FIG. 10 is a schematic diagram showing a stereoscopic image display device according to a fourth embodiment. [Figure 16] FIG. 10 is a plan view showing a self-luminous display panel according to a fourth embodiment. [Figure 17] FIG. 10 is a diagram showing the relationship between the brightness half-life and the brightness of an organic EL element according to the fourth embodiment. [Figure 18] FIG. 10 is a diagram showing a luminance reduction rate according to the fourth embodiment. [Figure 19] 10 is a diagram showing the relationship between the luminance of an organic EL element, the time during which the organic EL element emits light, and the time until the luminance is reduced to half of the time of a self-luminous display panel according to the fourth embodiment. FIG. [Figure 20] 10A and 10B are diagrams for explaining display control of a liquid crystal display panel according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, a stereoscopic image display device according to an embodiment will be described with reference to the drawings.

[0013] <Embodiment 1> A stereoscopic image display device 10 according to this embodiment will be described with reference to FIGS. 1 to 12. The stereoscopic image display device 10 is a display device that displays stereoscopic images using a DFD (Depth Fused 3D) method. The stereoscopic image display device 10 is used as a head-mounted display in combination with, for example, eyepieces. In this embodiment, the stereoscopic image display device 10 using a monochrome liquid crystal panel will be described as an example.

[0014] (Overall composition) First, we will explain the overall configuration of the stereoscopic image display device 10. The stereoscopic image display device 10 includes a display unit 20, a variable-focus lens unit 40, and a control unit 80, as shown in FIG.

[0015] The display unit 20 sequentially displays a first image and a second image in a time-division manner. In this embodiment, the display unit 20 emits display light PL1 for the first image and the second image as polarized light polarized in a predetermined first direction. The variable-focus lens unit 40 switches the focal length of the display light PL1 for the first image and the focal length of the display light PL1 for the second image, thereby forming virtual images of the first image and the second image on the first display surface 102 and the second display surface 104, respectively. The variable-focus lens unit 40 includes a polarization switching unit 50 and a polarized bifocal lens 60. The polarization switching unit 50 switches the polarization direction of the display light PL1 emitted from the display unit 20 between a predetermined first direction and a predetermined second direction, and then emits the light. The polarized bifocal lens 60 is a lens whose focal length for the light emitted from the polarization switching unit 50 varies depending on the polarization direction of the emitted light. The control unit 80 controls the display of the display unit 20. The control unit 80 supplies a first image signal for displaying a first image on the display unit 20, a second image signal for displaying a second image, and a minimum luminance signal (described later) to the display unit 20. Furthermore, the control unit 80 controls the switching of the polarization direction of the polarization switching unit 50.

[0016] 1 (left direction on the paper) is referred to as the +Z direction, the upward direction (upward on the paper) is referred to as the +Y direction, and the direction perpendicular to the +Y and +Z directions (toward the viewer on the paper) is referred to as the +X direction. Furthermore, the first image signal for displaying the first image and the second image signal for displaying the second image are also collectively referred to as image signals.

[0017] (Display unit) The display unit 20 of the stereoscopic image display device 10 includes a liquid crystal display panel 22 and a light source unit 32. The liquid crystal display panel 22 of the display unit 20 modulates light emitted from the light source unit 32 based on a first image signal, a second image signal, and a minimum luminance signal supplied from the control unit 80, and sequentially displays a first image and a second image in a time-division manner. The liquid crystal display panel 22 emits display light PL1 of an image (e.g., the first image and the second image) as polarized light whose polarization direction is a predetermined first direction. The display light PL1 emitted from the liquid crystal display panel 22 is incident on the polarization switching unit 50. In this embodiment, the predetermined first direction is the X direction.

[0018] The first and second images are two-dimensional images of the display object projected from the observer's side onto first display surface 102 and second display surface 104, which are located at different positions in the depth direction (+Z direction) as seen from the observer. First display surface 102 and second display surface 104 will be described later.

[0019] The liquid crystal display panel 22 is, for example, a transmissive TN (Twisted Nematic) liquid crystal panel that is driven by active matrix driving using line-sequential scanning with TFTs (Thin Film Transistors). As shown in FIG. 2, the liquid crystal display panel 22 includes pixels P arranged in a matrix, a gate driver 23G, and a data driver 23D. The gate driver 23G sequentially selects the pixels P row by row and performs line-sequential scanning from the +Y side to the -Y side. The data driver 23D supplies a voltage corresponding to an image signal or a minimum luminance signal to each selected pixel P, thereby writing the image signal or minimum luminance signal to each pixel P. Note that FIG. 2 illustrates only a portion of the pixels P arranged in a matrix. The liquid crystal display panel 22 also includes a light-transmitting substrate, TFTs, liquid crystal, polarizing plates, and other components (not shown).

[0020] The light source section 32 of the display unit 20 is a light source for the liquid crystal display panel 22. The light source section 32 is, for example, a direct backlight provided on the back surface of the liquid crystal display panel 22. The light source section (backlight) 32 includes LED (light emitting diode) elements, a reflective sheet, a diffusion sheet, etc., which are not shown.

[0021] (variable focus lens unit) The polarization switching unit 50 of the stereoscopic image display device 10 switches the polarization direction of the display light PL1 emitted from the display unit 20 between a predetermined first direction (X direction) and a predetermined second direction based on a switching signal synchronized with the image signal. In this embodiment, the predetermined second direction is the Y direction. Specifically, when a first image is displayed on the liquid crystal display panel 22 of the display unit 20, the polarization switching unit 50 outputs the incident display light PL1 while maintaining the polarization direction in the X direction. On the other hand, when a second image is displayed on the liquid crystal display panel 22 of the display unit 20, the polarization switching unit 50 switches the polarization direction of the incident display light PL1 to the Y direction and outputs it.

[0022] The polarization switching unit 50 is, for example, a TN liquid crystal element with a twist angle of 90°. As shown in FIG. 3, the polarization switching unit (TN liquid crystal element) 50 includes liquid crystal 52, two light-transmitting substrates 54a and 54b, and an alignment film (not shown) that aligns the liquid crystal 52. The light-transmitting substrate 54a and the light-transmitting substrate 54b each have an electrode 53 that applies a voltage to the liquid crystal 52. The light-transmitting substrate 54a and the light-transmitting substrate 54b are bonded together with a sealant 56, sandwiching the liquid crystal 52. When an OFF-level switching signal is supplied to the polarization switching unit 50, the polarization direction of the display light PL1 is rotated by 90° and the display light PL2 is emitted whose polarization direction is in the Y direction. On the other hand, when an ON-level switching signal is supplied to the polarization switching unit 50, the liquid crystal 52 is oriented perpendicular to the light-transmitting substrates 54a and 54b, and the polarization switching unit 50 maintains the polarization direction of the display light PL1 in the X direction and emits the display light PL2. The display light PL2 emitted from the polarization switching unit 50 is incident on the polarized bifocal lens 60. The switching signal will be described later.

[0023] The polarized bifocal lens 60 of the stereoscopic image display device 10 is a lens whose focal length with respect to the display light PL2 emitted from the polarization switching unit 50 varies depending on the polarization direction (X direction and Y direction) of the display light PL2. The polarized bifocal lens 60 forms the first image and the second image on the first display surface 102 and the second display surface 104, respectively, as virtual images as seen by the viewer. The first display surface 102 and the second display surface 104 are virtual display surfaces located at different positions in the depth direction (+Z direction) as seen by the viewer. In this embodiment, as shown in FIG. 1 , the first display surface 102 and the second display surface 104 are located farther away from the viewer than the display unit 20. Furthermore, the first display surface 102 is located closer to the viewer (-Z side) than the second display surface 104.

[0024] The observer views the virtual image of the first image on the first display surface 102 and the virtual image of the second image on the second display surface 104, which are displayed sequentially in a time-division manner, and recognizes that the display object is located between the first display surface 102 and the second display surface 104. The position of the display object recognized by the observer can be changed by adjusting the ratio of the brightness (e.g., luminance) of the first image and the second image. For example, when the luminance ratio of the first image and the second image is 1:1, the observer recognizes that the display object is located midway between the first display surface 102 and the second display surface 104.

[0025] The polarized bifocal lens 60 is, for example, a liquid crystal lens. The polarized bifocal lens (liquid crystal lens) 60 includes a first light-transmitting substrate 61, a second light-transmitting substrate 62, and a liquid crystal 64, as shown in FIG.

[0026] The first light-transmitting substrate 61 and the second light-transmitting substrate 62 are, for example, glass substrates. The first light-transmitting substrate 61 has a resin Fresnel lens 66 on a first main surface 61a facing the second light-transmitting substrate 62. The first light-transmitting substrate 61 and the second light-transmitting substrate 62 are bonded together with a sealant 67, sandwiching a liquid crystal 64 therebetween. The liquid crystal 64 is, for example, a nematic liquid crystal having positive refractive index anisotropy (Δn=ne-no>0, where n e is the extraordinary ray refractive index and n no is the ordinary ray refractive index). The liquid crystal 64 is aligned in the Y direction by an alignment film (not shown).

[0027] When display light PL2 of a first image, whose polarization direction is in the X direction, enters the polarized bifocal lens, the nematic liquid crystal with positive refractive index anisotropy is oriented in the Y direction, so the focal length of the polarized bifocal lens 60 for the display light PL2 is long, and the first image is formed on the first display surface 102. On the other hand, when display light PL2 of a second image, whose polarization direction is in the Y direction, enters the polarized bifocal lens, the focal length of the polarized bifocal lens 60 for the display light PL2 is short, and the second image is formed on the second display surface 104.

[0028] (Control unit) The control unit 80 of the stereoscopic image display device 10 generates first image data representing a first image and second image data representing a second image based on three-dimensional object data representing a display target input from an external device. The three-dimensional object data includes coordinate data representing the position of the display target in the display space, color data representing the color of the display target, brightness data representing the brightness of the display target, etc.

[0029] The control unit 80 also controls the display of the display unit 20 by supplying a first image signal for displaying the first image, a second image signal for displaying the second image, and a minimum luminance signal to the liquid crystal display panel 22 (display unit 20). Furthermore, the control unit 80 controls the polarization switching unit 50 by supplying a switching signal to the polarization switching unit 50. As shown in FIG. 5 , the control unit 80 has a storage unit 82, an image generation unit 84, a display drive unit 86, and a polarization switching drive unit 88.

[0030] The storage unit 82 of the control unit 80 stores programs that cause the image generation unit 84, the display drive unit 86, and the polarization switching drive unit 88 to function. The storage unit 82 also stores various data such as display surface data, viewpoint data, the distance between the observer and the first display surface 102, and the distance between the observer and the second display surface 104. The display surface data is coordinate data that represents the positions of the first display surface 102 and the second display surface 104 in a display space (three-dimensional space) in which the display object is displayed. The viewpoint data is coordinate data that represents the position of the observer's viewpoint in the display space.

[0031] An image generation unit 84 of the control unit 80 calculates a ratio between the luminance of the first image and the luminance of the second image based on the three-dimensional object data, the display surface data, and the viewpoint data, and further generates first image data representing the first image and second image data representing the second image. The image generation unit 84 outputs the first image data and the second image data to a storage unit 82 (frame memory) and stores them in the storage unit 82. Hereinafter, the first image data and the second image data will also be collectively referred to as image data.

[0032] The display drive unit 86 of the control unit 80 forms a first display period DP1, in which a first image is displayed, and a second display period DP2, in which a second image is displayed, each from a plurality of frame periods FP. Furthermore, the display drive unit 86 controls the luminance of the pixel P of the liquid crystal display panel 22 to the minimum luminance Lmin of the pixel P during the last frame period FP of the plurality of frame periods FP that form the first display period DP1. The display drive unit 86 controls the luminance of the pixel P of the liquid crystal display panel 22 to the minimum luminance Lmin of the pixel P during the last frame period FP of the plurality of frame periods FP that form the second display period DP2. The minimum luminance Lmin of the pixel P is calculated in advance and stored in the storage unit 82. Controlling the luminance of the pixel P of the liquid crystal display panel 22 to the minimum luminance Lmin of the pixel P can also be expressed as setting the gradation of the pixel P of the liquid crystal display panel 22 to zero gradation.

[0033] Hereinafter, the first display period DP1 and the second display period DP2 will also be collectively referred to as the display period. Furthermore, the minimum luminance Lmin of the pixel P will also be referred to as the minimum luminance Lmin.

[0034] The display drive unit 86 sequentially reads out the first image data and the second image data from the storage unit 82, and generates a first image signal for displaying the first image and a second image signal for displaying the second image. In addition, the display drive unit 86 generates a minimum luminance signal for controlling the luminance of the pixel P of the liquid crystal display panel 22 to the minimum luminance Lmin in the last frame period FP of the display period.

[0035] The display driver 86 supplies the generated image signal and minimum luminance signal to the liquid crystal display panel 22. The display driver 86 also supplies a synchronization signal synchronized with the display period to the polarization switching driver 88. Display control of the liquid crystal display panel 22 will be described later.

[0036] The polarization switching drive unit 88 of the control unit 80 generates a switching signal based on the synchronization signal supplied from the display drive unit 86. The polarization switching drive unit 88 also supplies the generated switching signal to the polarization switching unit 50. In this embodiment, when the first image is displayed on the liquid crystal display panel 22, the polarization switching drive unit 88 sets the switching signal to an ON level and supplies the switching signal to the polarization switching unit 50.

[0037] FIG. 6 shows the hardware configuration of the control unit 80. The control unit 80 includes a CPU (Central Processing Unit) 92, a ROM (Read Only Memory) 94, a RAM (Random Access Memory) 96, and an input / output interface 98. The CPU 92, ROM 94, RAM 96, and input / output interface 98 are connected via a bus 99. The CPU 92 executes various processes. The ROM 94 stores programs and data. The RAM 96 stores data. The input / output interface 98 inputs and outputs signals between the CPU 92, the display unit 20 (liquid crystal display panel 22), the variable-focus lens unit 40 (polarization switching unit 50), and external devices. The functions of the control unit 80 are realized by the CPU 92 executing programs stored in the ROM 94.

[0038] Display control of the liquid crystal display panel 22 will now be described. For ease of understanding, in this embodiment, the first image will be described as an image with uniform high luminance across the entire surface (a gray image close to white) as shown in Fig. 7, and the second image will be described as an image with uniform low luminance across the entire surface (a gray image close to black) as shown in Fig. 8. The display drive unit 86 supplies signals to the liquid crystal display panel 22 at a cycle of 240 Hz (frame period: 4.2 ms), and the liquid crystal display panel 22 performs line-sequential scanning (i.e., writing to pixels P) at a cycle of 240 Hz.

[0039] FIG. 9 is a diagram illustrating display control of the liquid crystal display panel 22 and control of the polarization switching unit 50. In FIG. 9, the first row shows signals (first image signal, second image signal, and minimum luminance signal) supplied from the display drive unit 86 of the control unit 80 to the liquid crystal display panel 22. The second row of FIG. 9 shows the luminance of pixels P in the first row in line sequential scanning of the liquid crystal display panel 22, and the third row of FIG. 9 shows the luminance of pixels P in the middle row in line sequential scanning of the liquid crystal display panel 22. The fourth row of FIG. 9 shows the luminance of pixels P in the last row in line sequential scanning of the liquid crystal display panel 22. The fifth row of FIG. 9 shows a switching signal supplied from the polarization switching drive unit 88 of the control unit 80 to the polarization switching unit 50, and the sixth row of FIG. 9 shows the polarization direction of display light PL2 emitted from the polarization switching unit 50.

[0040] 9, the display driver 86 of the control unit 80 forms each of a first display period DP1 in which a first image is displayed and a second display period DP2 in which a second image is displayed, from two frame periods FP. Then, as shown in the first row of FIG. 9, the display driver 86 supplies an image signal (first image signal or second image signal) to the liquid crystal display panel 22 in the first frame period FP of the two frame periods FP, and supplies a minimum luminance signal to the liquid crystal display panel 22 in the last frame period FP (second frame) of the two frame periods FP. Specifically, the display driver 86 sequentially supplies the first image signal, minimum luminance signal, second image signal, and minimum luminance signal to the liquid crystal display panel 22 at a cycle of 240 Hz (frame period FP: 4.2 ms).

[0041] Hereinafter, the luminance of pixel P in the first image signal is defined as La, and the luminance of pixel P in the second image signal is defined as Lb. The luminance La of pixel P in the first image signal corresponds to the luminance of pixel P displaying the first image on the liquid crystal display panel 22, and also corresponds to a predetermined luminance. The luminance Lb of pixel P in the second image signal corresponds to the luminance of pixel P displaying the second image on the liquid crystal display panel 22, and also corresponds to a predetermined luminance.

[0042] Furthermore, the average luminance of the pixels P of the liquid crystal display panel 22 during the first display period DP1 in which the first image is displayed is designated DL1av, and the average luminance of the pixels P of the liquid crystal display panel 22 during the second display period DP2 in which the second image is displayed is designated DL2av. The average luminance of the pixels P of the liquid crystal display panel 22 during a display period refers to the luminance obtained by averaging the luminance of the pixels P of the liquid crystal display panel 22 over the display period. The average luminance DL1av and the average luminance DL2av are collectively referred to as average luminance.

[0043] The liquid crystal display panel 22 sequentially performs line-sequential scanning (writing to pixels P) at a cycle of 240 Hz in response to signals sequentially supplied from the display drive unit 86. The liquid crystal display panel 22 sequentially displays a first image and a second image.

[0044] 9, the luminance of the pixel P on the first row in the line-sequential scanning of the liquid crystal display panel 22 becomes luminance La near the start of the first frame period FP of the first display period DP1, and becomes minimum luminance Lmin near the start of the last frame period FP of the first display period DP1. The luminance of the pixel P on the first row in the line-sequential scanning of the liquid crystal display panel 22 becomes luminance Lb near the start of the first frame period FP of the second display period DP2, and becomes minimum luminance Lmin near the start of the last frame period FP of the second display period DP2.

[0045] During a first display period DP1 formed from two frame periods FP, the luminance of pixels P on the first row in line-sequential scanning of the liquid crystal display panel 22 is luminance La for one frame period FP and reaches the minimum luminance Lmin for one frame period FP. During a second display period DP2 formed from two frame periods FP, the luminance of pixels P on the first row in line-sequential scanning of the liquid crystal display panel 22 is luminance Lb for one frame period FP and reaches the minimum luminance Lmin for one frame period FP. Therefore, for the first row in line-sequential scanning, the average luminance DL1av of pixels P on the liquid crystal display panel 22 during the first display period DP1 is expressed as DL1av = (La + Lmin) / 2, and the average luminance DL2av of pixels P on the liquid crystal display panel 22 during the second display period DP2 is expressed as DL2av = (Lb + Lmin) / 2.

[0046] 9, the luminance of the pixel P in the center row in line-sequential scanning of the liquid crystal display panel 22 becomes luminance La near the center of the first frame period FP of the first display period DP1, and becomes minimum luminance Lmin near the center of the last frame period FP of the first display period DP1.The luminance of the pixel P in the center row becomes luminance Lb near the center of the first frame period FP of the second display period DP2, and becomes minimum luminance Lmin near the center of the last frame period FP of the second display period DP2.

[0047] Similarly to the first row, in the center row of the line-sequential scanning of the liquid crystal display panel 22, the luminance of the pixel P of the liquid crystal display panel 22 in the first display period DP1 is luminance La for one frame period FP and reaches the minimum luminance Lmin for one frame period FP. Also, in the second display period DP2, the luminance of the pixel P of the center row of the liquid crystal display panel 22 is luminance Lb for one frame period FP and reaches the minimum luminance Lmin for one frame period FP. Therefore, in the center row as well, the average luminance DL1av is expressed as DL1av = (La + Lmin) / 2, and the average luminance DL2av is expressed as DL2av = (Lb + Lmin) / 2.

[0048] 9, the luminance of the pixel P in the last row in the line-sequential scanning of the liquid crystal display panel 22 becomes luminance La near the end of the first frame period FP of the first display period DP1, and becomes the minimum luminance Lmin near the end of the last frame period FP of the first display period DP1.The luminance of the pixel P in the last row becomes luminance Lb near the end of the first frame period FP of the second display period DP2, and becomes the minimum luminance Lmin near the end of the last frame period FP of the second display period DP2.

[0049] For the pixels P in the last row, the luminance of the pixels P in the liquid crystal display panel 22 in the first display period DP1 is luminance La for one frame period FP and reaches the minimum luminance Lmin for one frame period FP. Similarly, for the pixels P in the last row of the liquid crystal display panel 22 in the second display period DP2, the luminance is luminance Lb for one frame period FP and reaches the minimum luminance Lmin for one frame period FP. For the last row, the average luminance DL1av is also expressed as DL1av=(La+Lmin) / 2, and the average luminance DL2av is also expressed as DL2av=(Lb+Lmin) / 2.

[0050] As described above, in this embodiment, the average luminance DL1av is expressed as DL1av=(La+Lmin) / 2, and the average luminance DL2av is expressed as DL2av=(Lb+Lmin) / 2, regardless of the position in the line sequential direction of the liquid crystal display panel 22. That is, the display period (first display period DP1, second display period DP2) is formed from a plurality of frame periods FP (two frame periods FP), and in the last frame period FP (second frame) of the plurality of frame periods FP that form the display period, the luminance of the pixels P of the liquid crystal display panel 22 is controlled to the minimum luminance Lmin. Therefore, the stereoscopic image display device 10 can control the average luminance (average luminance DL1av, average luminance DL2av) of the pixels P of the liquid crystal display panel 22 during the display period, regardless of the position in the line sequential direction of the liquid crystal display panel 22.

[0051] In this embodiment, if the luminance of pixel P in the first image data is L1 and the luminance of pixel P in the second image data is L2, the display drive unit 86 sets the luminance of pixel P in the first image signal (i.e., the luminance of pixel P displaying the first image on the liquid crystal display panel 22) La and the luminance of pixel P in the second image signal (i.e., the luminance of pixel P displaying the second image on the liquid crystal display panel 22) Lb so as to satisfy the following equations (1) and (2). Note that the luminance L1 of pixel P in the first image data and the luminance L2 of pixel P in the second image data are also expressed as the luminance to be displayed by the liquid crystal display panel 22 or the target luminance of the liquid crystal display panel 22.

[0052]

number

number

[0053] That is, the display drive unit 86 sets the luminance of the pixel P in the pixel signal (i.e., the luminance of the pixel P displaying the image on the liquid crystal display panel 22) to a luminance that matches the luminance of the pixel P in the image data with the average luminance of the pixel P on the liquid crystal display panel 22 during the display period. This enables the stereoscopic image display device 10 to allow the viewer to recognize the correct first and second images.

[0054] On the other hand, when the display driver 86 forms each of the first display period DP1 in which the first image is displayed and the second display period DP2 in which the second image is displayed from one frame period FP (hereinafter referred to as a comparative example), the average luminance (average luminance DL1av, average luminance DL2av) of the pixels P of the liquid crystal display panel 22 during the display period differs depending on the position in the line-sequential direction of the liquid crystal display panel 22, as shown in Fig. 10. As a result, the viewer perceives the first image as shown in Fig. 11 and the second image as shown in Fig. 12. As a result, in the comparative example, the first image and the second image are not displayed correctly, and the viewer perceives a three-dimensional image having a different shape from the three-dimensional image that should be displayed.

[0055] Returning to the fifth row of Fig. 9, the polarization switching drive unit 88 of the control unit 80 supplies an ON-level switching signal to the polarization switching unit 50 in synchronization with the supply of the first image signal from the display drive unit 86. In addition, the polarization switching drive unit 88 supplies an OFF-level switching signal to the polarization switching unit 50 in synchronization with the supply of the second image signal from the display drive unit 86. As shown in the sixth row of Fig. 9, the polarization switching unit 50 switches the polarization direction of the display light PL2 in response to the switching signal.

[0056] As described above, the display period is formed from a plurality of frame periods FP, and in the last frame period FP of the plurality of frame periods FP that form the display period, the luminance of the pixel P of the liquid crystal display panel 22 is controlled to the minimum luminance Lmin of the pixel P, so the stereoscopic image display device 10 can control the average luminance of the pixel P of the liquid crystal display panel 22 during the display period, regardless of the position in the line sequential direction of the liquid crystal display panel 22. Furthermore, by setting the luminance of the pixel P in the pixel signal (the luminance of the pixel P displaying the image on the liquid crystal display panel 22) to a luminance that matches the luminance of the pixel P in the image data and the average luminance of the pixel P of the liquid crystal display panel 22 during the display period, the stereoscopic image display device 10 can allow the viewer to recognize the correct first and second images and display a correct stereoscopic image.

[0057] <Embodiment 2> In the first embodiment, the display period is formed of two frame periods FP, and the luminance of the pixels P of the liquid crystal display panel 22 is controlled to the minimum luminance Lmin in the last frame period FP of the two frame periods FP. The display period may be formed of a plurality of frame periods FP. Furthermore, the luminance of the pixels P of the liquid crystal display panel 22 may be controlled to the minimum luminance Lmin in a frame period FP other than the last frame period FP of the plurality of frame periods FP that form the display period.

[0058] Like the stereoscopic image display device 10 of Embodiment 1, the stereoscopic image display device 10 of this embodiment includes a display unit 20, a variable-focus lens unit 40, and a control unit 80. The configuration of the stereoscopic image display device 10 of this embodiment is the same as the configuration of the stereoscopic image display device 10 of Embodiment 1, except for the configuration of the display drive unit 86 of the control unit 80. Here, the configuration of the display drive unit 86 of the control unit 80 of this embodiment and display control of the liquid crystal display panel 22 will be described.

[0059] The display drive unit 86 of this embodiment forms a display period from a plurality of frame periods FP, similar to the display drive unit 86 of embodiment 1. Furthermore, the display drive unit 86 of this embodiment controls the luminance of the pixel P of the liquid crystal display panel 22 to the minimum luminance Lmin of the pixel P in the last frame period FP of the plurality of frame periods FP that form the display period.

[0060] Specifically, the display driver 86 of this embodiment forms each of a first display period DP1 in which a first image is displayed and a second display period DP2 in which a second image is displayed, from three frame periods FP, as shown in Fig. 13. The display driver 86 of this embodiment supplies an image signal (first image signal or second image signal) to the liquid crystal display panel 22 in the first frame period FP of the three frame periods FP, as shown in the first row of Fig. 13. Furthermore, the display driver 86 of this embodiment supplies a minimum luminance signal to the liquid crystal display panel 22 in the second frame period FP and the last frame period FP (third frame) of the three frame periods FP.

[0061] The liquid crystal display panel 22 sequentially performs line-sequential scanning (writing to the pixels P) in response to signals sequentially supplied from the display drive unit 86. The liquid crystal display panel 22 sequentially displays the first image and the second image.

[0062] 13, in a first display period DP1 formed from three frame periods FP, the luminance of the pixel P in the first row in the line-sequential scanning of the liquid crystal display panel 22 is luminance La for one frame period FP and reaches the minimum luminance Lmin for two frame periods FP. Also, in a second display period DP2 formed from three frame periods FP, the luminance of the pixel P in the first row in the line-sequential scanning of the liquid crystal display panel 22 is luminance Lb for one frame period FP and reaches the minimum luminance Lmin for two frame periods FP. Therefore, in the first row in the line-sequential scanning, the average luminance DL1av of the pixel P in the liquid crystal display panel 22 in the first display period DP1 is expressed as DL1av = (La + 2 × Lmin) / 3, and the average luminance DL2av of the pixel P in the liquid crystal display panel 22 in the second display period DP2 is expressed as DL2av = (Lb + 2 × Lmin) / 3.

[0063] 13, during the first display period DP1, the luminance of the pixels P in the center row and the last row of the liquid crystal display panel 22 also becomes luminance La for one frame period FP and reaches the minimum luminance Lmin for two frame periods FP. Also, during the second display period DP2, the luminance of the pixels P in the center row and the last row of the liquid crystal display panel 22 also becomes luminance Lb for one frame period FP and reaches the minimum luminance Lmin for two frame periods FP. Therefore, for the center row and the last row in line-sequential scanning, the average luminance DL1av is expressed as DL1av = (La + 2 × Lmin) / 3, and the average luminance DL2av is expressed as DL2av = (Lb + 2 × Lmin) / 3.

[0064] As described above, in this embodiment, the average luminance DL1av is expressed as DL1av = (La + 2 × Lmin) / 3, and the average luminance DL2av is expressed as DL2av = (Lb + 2 × Lmin) / 3, regardless of the position in the line sequential direction on the liquid crystal display panel 22. In this embodiment as well, the display period is formed from a plurality of frame periods FP (three frame periods FP), and the luminance of the pixel P is controlled to the minimum luminance Lmin in the last frame period FP (third frame) of the plurality of frame periods FP that form the display period. Therefore, the stereoscopic image display device 10 can control the average luminance of the pixel P in the display period, regardless of the position in the line sequential direction on the liquid crystal display panel 22.

[0065] In this embodiment as well, the display drive unit 86 sets the luminance of pixel P in the pixel signal to a luminance that matches the luminance of pixel P in the image data with the average luminance of pixel P on the liquid crystal display panel 22 during the display period. Specifically, the luminance La of pixel P in the first image signal and the luminance Lb of pixel P in the second image signal are set so as to satisfy the following equations (3) and (4). This enables the stereoscopic image display device 10 to allow the viewer to recognize the correct first and second images.

[0066]

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number

[0067] As described above, in this embodiment as well, the stereoscopic image display device 10 can control the average luminance of the pixels P of the liquid crystal display panel 22 during the display period, regardless of the position in the line-sequential direction of the liquid crystal display panel 22. Furthermore, the stereoscopic image display device 10 of this embodiment can allow the viewer to recognize the correct first image and second image, and can display a correct stereoscopic image.

[0068] <Embodiment 3> In the first and second embodiments, the display drive unit 86 controls the luminance of the pixel P of the liquid crystal display panel 22 to luminance La during one frame period FP among the plurality of frame periods FP that form the first display period DP1, and controls the luminance of the pixel P of the liquid crystal display panel 22 to luminance Lb during one frame period FP among the plurality of frame periods FP that form the second display period DP2. The display drive unit 86 may control the luminance of the pixel P of the liquid crystal display panel 22 to luminance La or luminance Lb during multiple frame periods FP.

[0069] Like the stereoscopic image display device 10 of Embodiment 1, the stereoscopic image display device 10 of this embodiment includes a display unit 20, a variable-focus lens unit 40, and a control unit 80. The configuration of the stereoscopic image display device 10 of this embodiment is the same as the configuration of the stereoscopic image display device 10 of Embodiment 1, except for the configuration of the display drive unit 86 of the control unit 80. Here, the configuration of the display drive unit 86 of the control unit 80 of this embodiment and display control of the liquid crystal display panel 22 will be described.

[0070] In this embodiment, the display driver 86 forms each of a first display period DP1 in which a first image is displayed and a second display period DP2 in which a second image is displayed, from three frame periods FP, as shown in Fig. 14. The display driver 86 of this embodiment supplies an image signal (first image signal or second image signal) to the liquid crystal display panel 22 in the first frame period FP and the second frame period FP of the three frame periods FP, as shown in the first row of Fig. 14. Furthermore, the display driver 86 of this embodiment supplies a minimum luminance signal to the liquid crystal display panel 22 in the last frame period FP (third frame) of the three frame periods FP.

[0071] The liquid crystal display panel 22 sequentially performs line-sequential scanning (writing to the pixels P) in response to signals sequentially supplied from the display drive unit 86. The liquid crystal display panel 22 sequentially displays the first image and the second image.

[0072] 14, in a first display period DP1 formed from three frame periods FP, the luminance of the pixel P in the first row in the line-sequential scanning of the liquid crystal display panel 22 is luminance La for two frame periods FP and reaches the minimum luminance Lmin for one frame period FP. Also, in a second display period DP2 formed from three frame periods FP, the luminance of the pixel P in the first row in the line-sequential scanning of the liquid crystal display panel 22 is luminance Lb for two frame periods FP and reaches the minimum luminance Lmin for one frame period FP. Therefore, in the first row in the line-sequential scanning, the average luminance DL1av of the pixel P in the liquid crystal display panel 22 in the first display period DP1 is expressed as DL1av = (2 × La + Lmin) / 3, and the average luminance DL2av of the pixel P in the liquid crystal display panel 22 in the second display period DP2 is expressed as DL2av = (2 × Lb + Lmin) / 3.

[0073] 14, the luminance of the pixels P in the center row and the last row of the liquid crystal display panel 22 in the first display period DP1 also becomes luminance La for two frame periods FP and reaches the minimum luminance Lmin for one frame period FP. Similarly, the luminance of the pixels P in the center row and the last row of the liquid crystal display panel 22 in the second display period DP2 also becomes luminance Lb for two frame periods FP and reaches the minimum luminance Lmin for one frame period FP. Therefore, for the center row and the last row in line-sequential scanning, the average luminance DL1av is expressed as DL1av = (La + 2 × Lmin) / 3, and the average luminance DL2av is expressed as DL2av = (Lb + 2 × Lmin) / 3.

[0074] As described above, in the last frame period FP among the multiple frame periods FP that form the display period, the brightness of pixel P is controlled to the minimum brightness Lmin, so that the stereoscopic image display device 10 can control the average brightness of pixel P during the display period regardless of its position in the line sequential direction of the liquid crystal display panel 22.

[0075] In this embodiment as well, the display drive unit 86 sets the luminance of pixel P in the pixel signal to a luminance that matches the luminance of pixel P in the image data with the average luminance of pixel P on the liquid crystal display panel 22 during the display period. Specifically, the luminance La of pixel P in the first image signal and the luminance Lb of pixel P in the second image signal are set so as to satisfy the following equations (5) and (6). This enables the stereoscopic image display device 10 to allow the viewer to recognize the correct first and second images.

[0076]

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[0077] Furthermore, in this embodiment, the luminance of the pixel P of the liquid crystal display panel 22 is controlled to luminance La or luminance Lb over multiple frame periods FP. Therefore, when the average luminance DL1av of Embodiments 1 and 2, in which the luminance of the pixel P of the liquid crystal display panel 22 is controlled to luminance La over one frame period FP, is the same as the average luminance DL1av of this embodiment, the luminance (luminance La) of the pixel P of the liquid crystal display panel 22 of this embodiment can be made smaller than the luminance (luminance La) of the pixel P of the liquid crystal display panel 22 of Embodiments 1 and 2. Furthermore, when the average luminance DL2av of Embodiments 1 and 2 is the same as the average luminance DL2av of this embodiment, the luminance (luminance Lb) of the pixel P of the liquid crystal display panel 22 of this embodiment can be made smaller than the luminance (luminance Lb) of the pixel P of the liquid crystal display panel 22 of Embodiments 1 and 2.

[0078] As described above, in this embodiment as well, the stereoscopic image display device 10 can control the average luminance of the pixels P of the liquid crystal display panel 22 during the display period, regardless of the position in the line-sequential direction of the liquid crystal display panel 22. Furthermore, the stereoscopic image display device 10 of this embodiment can allow the viewer to recognize the correct first image and second image, and can display a correct stereoscopic image.

[0079] <Embodiment 4> In the first to third embodiments, the display unit 20 of the stereoscopic image display device 10 includes a liquid crystal display panel 22 and a light source section 32. The configuration of the display unit 20 is not limited to this.

[0080] Like the stereoscopic image display device 10 of Embodiment 1, the stereoscopic image display device 10 of this embodiment includes a display unit 20, a variable-focus lens unit 40, and a control unit 80. Except for the configuration of the display unit 20, the configuration of the stereoscopic image display device 10 of this embodiment is the same as the configuration of the stereoscopic image display device 10 of Embodiments 1 to 3.

[0081] 15, the display unit 20 of this embodiment includes a self-luminous display panel 24 and a polarizing plate 34. The self-luminous display panel 24 is, for example, an organic EL display panel that is active-matrix driven by TFTs using line-sequential scanning. The polarizing plate 34 outputs light emitted from the self-luminous display panel 24 as display light PL1 whose polarization direction is a predetermined first direction.

[0082] 16, the self-luminous display panel 24 has pixels P arranged in a matrix, a gate driver 23G, and a data driver 23D. The configurations of the gate driver 23G and the data driver 23D of this embodiment are the same as those of the gate driver 23G and the data driver 23D of embodiments 1 to 3. The self-luminous display panel 24 includes a light-transmitting substrate, self-luminous elements (organic EL elements), TFTs, etc., which are not shown.

[0083] The display of the self-luminous display panel 24 is controlled in the same manner as the liquid crystal display panel 22 of Embodiments 1 to 3. Therefore, like the stereoscopic image display device 10 of Embodiments 1 to 3, the stereoscopic image display device 10 of this embodiment can control the average luminance of the pixels P of the self-luminous display panel 24 during the display period, regardless of the position in the line-sequential direction of the self-luminous display panel 24. Furthermore, the stereoscopic image display device 10 of this embodiment can allow the viewer to recognize the correct first image and second image, and can display a correct stereoscopic image.

[0084] In display control of the self-luminous display panel 24, when the display drive unit 86 controls the luminance of the pixel P of the self-luminous display panel 24 to luminance La or luminance Lb over multiple frame periods FP, as in the third embodiment, the luminance La and the luminance Lb can be reduced, thereby lengthening the time until the luminance of the self-luminous display panel 24 is reduced by half (luminance half-life time Th). This effect will be explained below using an organic EL display panel (organic EL element) as an example.

[0085] Current density J (mA / cm) of organic EL element 2 It is known that the relationship between the current density J and the luminance L (cd / m) when an organic EL element is continuously emitting light is expressed as follows: 2 ) are known to be proportional to each other. Therefore, the brightness half-life LT50 and the brightness L of an organic EL element can be expressed by the following formula (8) and as shown in Figure 17. N and b in formula (7) vary depending on the configuration and material of the organic EL element, but generally, N is 1.3 to 1.5, and b is about 5. Furthermore, A in formula (8) is a proportionality constant.

[0086]

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[0087] When the change in the luminance reduction rate DR is linearly approximated based on equation (8), the luminance reduction rate DR is expressed as shown in Fig. 18. In Fig. 18, the time at which the luminance reduction rate DR becomes 0.5 corresponds to the luminance half time Th of the self-luminous display panel 24 (organic EL display panel) of the embodiment.

[0088] Furthermore, the average luminance (L × t / T) of pixel P during the display period is set to 1000 cd / cm 2Assuming that the length T of the display period is 10 ms, an example of the relationship between the luminance L of the organic EL element, the time t during which the organic EL element emits light, and the luminance half-life Th ​​of the self-luminous display panel 24 is shown in Fig. 19. As shown in Fig. 19, the luminance half-life Th ​​can be extended by extending the time t during which the organic EL element emits light and reducing the luminance L of the organic EL element. That is, as in the display control of embodiment 3, the luminance of the pixel P of the self-luminous display panel 24 is controlled to luminance La or luminance Lb over multiple frame periods FP, and the luminance La and Lb are reduced, thereby extending the luminance half-life Th ​​(lifetime) of the self-luminous display panel 24.

[0089] <Modification> Although the embodiments have been described above, various modifications can be made to the present disclosure without departing from the spirit and scope of the present disclosure.

[0090] In the first embodiment, the light source section 32 of the display unit 20 is a direct type backlight. The light source section 32 is not limited to a direct type backlight. The light source section 32 of the display unit 20 may be, for example, a side edge type backlight.

[0091] Furthermore, the polarization switching section 50 is not limited to a TN liquid crystal element, but may be a PLZT (Lead Lanthanum Zirconate Titanate) element, an element utilizing the Faraday effect, or the like.

[0092] Furthermore, the variable-focus lens unit 40 does not have to be formed from the polarization switching section 50 and the polarized bifocal lens 60. For example, the variable-focus lens unit 40 may be a liquid lens whose focal length changes depending on the applied voltage. For example, a liquid lens that utilizes electrowetting can be used as the liquid lens.

[0093] In the embodiment, the stereoscopic image display device 10 is described as using a monochrome display panel (liquid crystal display panel 22, self-luminous display panel 24), but a color display panel may be used instead of the monochrome display panel. In this case, the pixel P may be a sub-pixel that is color-coded as R (red), G (green), B (blue), etc.

[0094] When the stereoscopic image display device 10 is used in a head-mounted display, the stereoscopic image display device 10 may include a variable-focus lens unit 40 for the right eye and a variable-focus lens unit 40 for the left eye. The head-mounted display may also include a stereoscopic image display device 10 for the right eye and a stereoscopic image display device 10 for the left eye.

[0095] In the embodiment, the control unit 80 generates the first image data and the second image data from the three-dimensional object data input from the external device. The control unit 80 may also receive the first image data and the second image data from the external device. In this case, the control unit 80 does not need to include the image generation unit 84.

[0096] In the second embodiment, the display drive unit 86 controls the luminance of the pixel P to the minimum luminance Lmin for two consecutive frame periods FP. In the third embodiment, the display drive unit 86 controls the luminance of the pixel P to the luminance La or the luminance Lb for two consecutive frame periods FP. The display drive unit 86 controls the luminance of the pixel P to the minimum luminance Lmin for the last frame period FP among the frame periods FP that form the display period, and controls the luminance of the pixel P to the luminance La or the luminance Lb for at least one frame period FP among the frame periods FP. For example, as shown in FIG. 20 , the display drive unit 86 may control the luminance of the pixel P in the following order: luminance La, minimum luminance Lmin, luminance La, minimum luminance Lmin, in four frame periods FP that form the first display period DP1. The display drive unit 86 may also control the luminance of the pixel P in the following order: luminance Lb, minimum luminance Lmin, luminance Lb, minimum luminance Lmin, in four frame periods FP that form the second display period DP2.

[0097] If the number of frame periods FP forming the display period is M (M: natural number) and the number of frames in which the brightness of pixel P is controlled to brightness La or brightness Lb is K (K: natural number), the display drive unit 86 may set brightness La and brightness Lb so as to satisfy the following equations (9) and (10).

[0098]

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[0099] Although the preferred embodiments have been described above, the present disclosure is not limited to such specific embodiments, and the present disclosure includes the inventions described in the claims and their equivalents. [Explanation of symbols]

[0100] 10 stereoscopic image display device, 20 display unit, 22 liquid crystal display panel, 23D data driver, 23G gate driver, 24 self-luminous display panel, 32 light source section, 34 polarizing plate, 40 variable focus lens unit, 50 polarization switching section, 52 liquid crystal, 53 electrode, 54a, 54b light-transmitting substrate, 56 sealing material, 60 polarized bifocal lens, 61 first light-transmitting substrate, 61a first main surface of first light-transmitting substrate, 62 second light-transmitting substrate, 64 liquid crystal, 66 Fresnel lens, 67 sealing material, 80 control section, 82 memory section, 84 image generation section, 86 display drive section, 88 polarization switching drive section, 92 CPU, 94 ROM, 96 RAM, 98 input / output interface, 99 bus, 102 first display surface, 104 second display surface, PL1, PL2 display light, P pixel, DP1 First display period, DP2 Second display period, FP Frame period, L, L1, L2, La, Lb Brightness, Lmin Minimum brightness, DL1av, DL2av Average brightness, LT50 Brightness half-life of organic EL element, J Current density, N, b Constant, A Proportionality constant, DR Brightness reduction rate, Th Brightness half-life of self-luminous display panel, t Time for organic EL element to emit light, T Length of display period, M, K Number

Claims

1. a liquid crystal display panel that sequentially displays a first image and a second image and emits display light for the first image and display light for the second image; a variable-focus lens unit that switches between a focal length for displaying the first image and a focal length for displaying the second image; a control unit that controls the display of the liquid crystal display panel, the first image and the second image are two-dimensional images of a display object projected from a side of the observer onto a first display surface and a second display surface that are located at different positions in a depth direction as viewed from the observer, respectively; the liquid crystal display panel displays the first image and the second image by line-sequential scanning; the variable-focus lens unit forms the first image and the second image as virtual images on the first display surface and the second display surface, respectively; The control unit forming a display period for displaying each of the first image and the second image from a plurality of frame periods; In the last frame period of the plurality of frame periods that form the display period, the luminance of the pixel of the liquid crystal display panel is controlled to the minimum luminance of the pixel. Stereoscopic image display device.

2. a self-luminous display panel that sequentially displays a first image and a second image and emits display light for the first image and display light for the second image; a variable-focus lens unit that switches between a focal length for displaying the first image and a focal length for displaying the second image; a control unit that controls the display of the self-luminous display panel, the first image and the second image are two-dimensional images of a display object projected from a side of the observer onto a first display surface and a second display surface that are located at different positions in a depth direction as viewed from the observer, respectively; the self-luminous display panel displays the first image and the second image by line-sequential scanning; the variable-focus lens unit forms the first image and the second image as virtual images on the first display surface and the second display surface, respectively; The control unit forming a display period for displaying each of the first image and the second image from a plurality of frame periods; In the last frame period of the plurality of frame periods that form the display period, the luminance of the pixel of the self-luminous display panel is controlled to the minimum luminance of the pixel. Stereoscopic image display device.

3. the control unit causes the luminance of the pixel in the pixel data representing each of the first image and the second image to match with an average luminance of the pixel during the display period; 3. The stereoscopic image display device according to claim 1 or 2.

4. the control unit controls the luminance of the pixel to the minimum luminance of the pixel for a plurality of the frame periods; 3. The stereoscopic image display device according to claim 1 or 2.

5. the control unit controls the luminance of the pixel to a predetermined luminance for a plurality of the frame periods; 3. The stereoscopic image display device according to claim 1 or 2.

Images