Head-up display

Abstract

To achieve miniaturization in a head-up display capable of projecting two virtual images with different degrees of inclination. [Solution] The head-up display 1 includes a liquid crystal display device 10 that emits a first light L1 corresponding to a first image G1 from the display surface 10a toward a light-transmitting body 2 along a first emission direction W1, and emits a second light L2 corresponding to a second image G2 from the display surface 10a along a second emission direction W2 different from the first emission direction W1, and a reflector 40 that receives the second light L2 and reflects the second light L2 toward the light-transmitting body 2 along the first emission direction W1.

Description

Technical Field

[0001] The present disclosure relates to a head-up display.

Background Art

[0002] As an example of a head-up display, Patent Document 1 discloses a vehicle display device that projects a plurality of virtual images at different positions from each other. Further, Patent Document 2 discloses a head-up display device that projects two virtual images in a state having different degrees of inclination from each other.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The head-up display of Patent Document 1 includes a plurality of display panels (liquid crystal display devices) in order to display a plurality of virtual images. Further, the head-up display of Patent Document 2 includes two display surfaces having different degrees of inclination from each other in order to display two virtual images. Thus, the head-up displays of Patent Documents 1 and 2 are relatively large in size by having a plurality of display surfaces for projecting a plurality of virtual images.

[0005] An object of the present disclosure is to reduce the size of a head-up display capable of projecting two virtual images having different degrees of inclination from each other.

Means for Solving the Problems

[0006] The head-up display of this disclosure comprises a liquid crystal display device that emits first light corresponding to a first image from a display surface toward a translucent material along a first emission direction, and emits second light corresponding to a second image from the display surface along a second emission direction different from the first emission direction, and a reflector having a reflective surface that receives the second light and reflects the second light toward the translucent material along the first emission direction.

[0007] Furthermore, the head-up display of the present disclosure includes a liquid crystal display device that emits first light corresponding to a first image from a display surface toward a light-transmitting material along a first emission direction, and emits second light corresponding to a second image from the display surface along a second emission direction different from the first emission direction; a quarter-phase difference plate into which the second light emitted from the display surface is incident; and a reflector having a reflective surface that reflects the light transmitted through the quarter-phase difference plate toward the display surface along the second emission direction via the quarter-phase difference plate, wherein the first angle between the orthogonal direction perpendicular to the display surface and the first emission direction, and the second angle between the orthogonal direction and the second emission direction are equal to each other, and the liquid crystal display device includes a reflective polarizer that allows linearly polarized light having a first polarization direction perpendicular to the first emission direction and the second emission direction to pass through, and reflects linearly polarized light having a second polarization direction perpendicular to the first emission direction, the second emission direction and the first polarization direction. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic diagram of a head-up display according to the first embodiment of the present disclosure. [Figure 2] Figure 2 is a conceptual diagram of the liquid crystal display device shown in Figure 1. [Figure 3] Figure 3 is a plan view of the liquid crystal display device shown in Figure 1. [Figure 4] Figure 4 is a side view of the liquid crystal display device shown in Figure 3. [Figure 5] Figure 5 shows the arrangement of the first and second subpixels as shown in Figure 3. [Figure 6] Figure 6 shows the circuit configuration of the display panel shown in Figure 3. [Figure 7] Figure 7 is a cross-sectional view of the display panel shown in Figure 3. [Figure 8] Figure 8 is a plan view of the parallax barrier shown in Figure 7. [Figure 9] Figure 9 shows the first and second virtual images perceived by the observer in the head-up display shown in Figure 1. [Figure 10] Figure 10 is a schematic diagram of a head-up display according to the second embodiment of the present disclosure. [Figure 11] Figure 11 is a schematic diagram of a head-up display according to the third embodiment of this disclosure. [Figure 12] Figure 12 is a cross-sectional view of the display panel of the liquid crystal display device shown in Figure 11. [Figure 13] Figure 13 shows the quarter phase difference plate shown in Figure 11 as viewed from a direction perpendicular to the reflective surface. [Figure 14] Figure 14 shows the first and second virtual images as viewed by the observer in the head-up display shown in Figure 1. [Figure 15] Figure 15 shows the arrangement of a first subpixel and a second subpixel in a liquid crystal display device provided in a modified head-up display according to an embodiment of the present disclosure. [Figure 16] Figure 16 is a plan view of a parallax barrier in a liquid crystal display device provided in a head-up display according to a modified embodiment of the present disclosure. [Modes for carrying out the invention]

[0009] The embodiments of this disclosure will be described below with reference to the drawings. This disclosure is not limited to the embodiments described below. Furthermore, the components described below include those that are readily conceivable to those skilled in the art, and those that are substantially the same. In addition, the components described below can be combined as appropriate.

[0010] Note that the disclosure is merely an example, and for those that can be easily conceived by those skilled in the art with appropriate modifications while maintaining the gist of the disclosure, they are naturally included in the scope of the present disclosure. Also, for the purpose of making the description clearer, the drawings may schematically represent the width, thickness, shape, etc. of each part compared to the actual embodiment, but it is merely an example and does not limit the interpretation of the present disclosure. Also, in this specification and each figure, elements similar to those previously described with respect to the existing figures may be denoted by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0011] The X direction, Y direction, and Z direction shown in the drawings are the depth direction, width direction, and height direction of the head-up display 1. The X direction, Y direction, and Z direction are orthogonal to each other. Note that the X direction, Y direction, and Z direction are an example, and the present disclosure is not limited to these directions.

[0012] <First Embodiment> FIG. 1 is a schematic diagram of a head-up display 1 according to a first embodiment of the present disclosure. The head-up display 1 (hereinafter sometimes referred to as HUD1) projects an image onto a light-transmitting body 2 to allow an observer to visually recognize a virtual image VG. The light-transmitting body 2 is plate-shaped and has light-transmitting properties. The light-transmitting body 2 is, for example, a vehicle windshield and a combiner, but it is needless to say that it is not limited to the windshield and the combiner, and any configuration in which the image output by HUD1 is projected is acceptable.

[0013] HUD1 includes a liquid crystal display device 10 and a reflector 40.

[0014] FIG. 2 is a conceptual diagram of the liquid crystal display device 10 shown in FIG. 1. In the display area DA of the liquid crystal display device 10, a first image G1 and a second image G2 are simultaneously displayed over the entire display area DA at different viewing angles.

[0015] Figure 3 is a plan view of the liquid crystal display device 10 shown in Figure 1. Figure 4 is a side view of the liquid crystal display device 10 shown in Figure 3. The first direction D1, second direction D2, and third direction D3 (corresponding to "orthogonal directions") shown in the drawings are orthogonal to each other and correspond to the depth direction, width direction, and height direction of the liquid crystal display device 10, respectively. In the first direction D1, the side indicated by the arrow corresponds to the +D1 side of the liquid crystal display device 10, and the opposite side corresponds to the -D1 side of the liquid crystal display device 10. In the second direction D2, the side indicated by the arrow corresponds to the +D2 side of the liquid crystal display device 10, and the opposite side corresponds to the -D2 side of the liquid crystal display device 10. In the third direction D3, the side indicated by the arrow corresponds to the +D3 side (upper side) of the liquid crystal display device 10, and the opposite side corresponds to the -D3 side (lower side) of the liquid crystal display device 10. Note that the first direction D1, second direction D2, and third direction D3 are examples, and this disclosure is not limited to these directions. Furthermore, in this specification, "planar view" means viewing the liquid crystal display device 10 along the third direction D3.

[0016] The liquid crystal display device 10 displays an image based on an image signal output from an external device (e.g., a car navigation system) that is electrically connected via a flexible wiring board (not shown). In this first embodiment, the liquid crystal display device 10 is arranged such that the third direction D3 and the Z direction are parallel. The liquid crystal display device 10 is also arranged such that the first direction D1 and the X direction are parallel, and the second direction D2 and the Y direction are parallel.

[0017] As shown in Figure 4, the liquid crystal display device 10 includes a display panel 20 and a light source device 30.

[0018] The display panel 20 is a transmissive liquid crystal display. The display panel 20 may also be, for example, an organic EL display or an inorganic EL display. As shown in Figure 3, the display panel 20 has a display area DA on its display surface 10a where an image is displayed. The display surface 10a is flat and planar. The display surface 10a is perpendicular to the third direction D3.

[0019] The display panel 20 has a plurality of pixels P arranged in a matrix in a plan view. The row direction is parallel to the first direction D1. The column direction is parallel to the second direction D2. In a plan view, the plurality of pixels P overlap with the display area DA. The pixels P have a first pixel P1 and a second pixel P2.

[0020] The first pixel P1 is the pixel corresponding to the first image G1. The first pixel P1 has a first sub-pixel SP1a, a second first sub-pixel SP1b, and a third first sub-pixel SP1c. The first first sub-pixel SP1a is a red sub-pixel. The second first sub-pixel SP1b is a green sub-pixel. The third first sub-pixel SP1c is a blue sub-pixel. Hereafter, when describing the first first sub-pixel SP1a, the second first sub-pixel SP1b, and the third first sub-pixel SP1c without distinction, they will simply be referred to as "first sub-pixel SP1".

[0021] The second pixel P2 is the pixel corresponding to the second image G2. The second pixel P2 has a first second sub-pixel SP2a, a second second sub-pixel SP2b, and a third second sub-pixel SP2c. The first second sub-pixel SP2a is a red sub-pixel. The second second sub-pixel SP2b is a green sub-pixel. The third second sub-pixel SP2c is a blue sub-pixel. Hereafter, when describing the first second sub-pixel SP2a, the second second sub-pixel SP2b, and the third second sub-pixel SP2c without distinction, they will simply be referred to as "second sub-pixel SP2".

[0022] Thus, the first pixel P1 has three first subpixels SP1, and the second pixel P2 has three second subpixels SP2. Needless to say, the number and color of the first subpixels SP1, and the number and color of the second subpixels SP2, are not limited to the above.

[0023] Figure 5 shows the arrangement of the first subpixel SP1 and the second subpixel SP2 as shown in Figure 3. In Figure 5, the first subpixel SP1 is marked with a rectangular shape indicated by a dashed line, and the second subpixel SP2 is marked with a rectangular shape indicated by a dotted line.

[0024] The first pixel P1 and the second pixel P2 are arranged along the row direction (first direction D1), respectively. Furthermore, the first pixel P1 and the second pixel P2 are arranged in a zigzag pattern along the column direction (second direction D2), respectively.

[0025] In the row direction, focusing on the first pixel P1, the first sub-pixel SP1a, the third sub-pixel SP1c, and the second sub-pixel SP1b are repeatedly arranged in this order. Also, in the row direction, focusing on the second pixel P2, the second sub-pixel SP2b, the first sub-pixel SP2a, and the third sub-pixel SP2c are repeatedly arranged in this order.

[0026] Furthermore, the first subpixel SP1 and the second subpixel SP2 are arranged alternately along the row direction. That is, in the row direction, the first subpixel SP1 and the second subpixel SP2 are adjacent to each other. Specifically, in the row direction, the first first subpixel SP1a is adjacent to at least one of the second second subpixel SP2b and the third second subpixel SP2c. Also, in the row direction, the second first subpixel SP1b is adjacent to at least one of the third second subpixel SP2c and the first second subpixel SP2a. Furthermore, in the row direction, the third first subpixel SP1c is adjacent to at least one of the first second subpixel SP2a and the second second subpixel SP2b.

[0027] Furthermore, in the row direction, the first second subpixel SP2a is adjacent to at least one of the second first subpixel SP1b and the third first subpixel SP1c. Also, in the row direction, the second second subpixel SP2b is adjacent to at least one of the third first subpixel SP1c and the first first subpixel SP1a. Moreover, in the row direction, the third second subpixel SP2c is adjacent to at least one of the first first subpixel SP1a and the second first subpixel SP1b.

[0028] Furthermore, the first subpixel SP1 and the second subpixel SP2 are arranged alternately along the column direction. That is, the first subpixel SP1 and the second subpixel SP2 are adjacent to each other in the column direction. Specifically, the first first subpixel SP1a and the first second subpixel SP2a are arranged alternately along the column direction. The second first subpixel SP1b and the second second subpixel SP2b are arranged alternately along the column direction. The third first subpixel SP1c and the third second subpixel SP2c are arranged alternately along the column direction.

[0029] Figure 6 shows the circuit configuration of the display panel 20 shown in Figure 3. The display panel 20 includes a drive circuit 21, as well as switching elements SW, sub-pixel electrodes PE, common electrodes CE, liquid crystal capacitors LC, and holding capacitors CS, which are present in the first sub-pixel SP1 and the second sub-pixel SP2, respectively. The first sub-pixel SP1 and the second sub-pixel SP2 are configured similarly.

[0030] The drive circuit 21 drives the display panel 20. The drive circuit 21 includes a signal processing circuit 21a, a signal output circuit 21b, and a scanning circuit 21c.

[0031] The signal processing circuit 21a outputs a first sub-pixel signal indicating the gradation of the first sub-pixel SP1 and a second sub-pixel signal indicating the gradation of the second sub-pixel SP2 to the signal output circuit 21b based on the image signal transmitted from an external device. The signal processing circuit 21a also outputs a clock signal to the signal output circuit 21b and the scanning circuit 21c to synchronize the operation of the signal output circuit 21b and the scanning circuit 21c.

[0032] The signal output circuit 21b outputs the first sub-pixel signal to the first sub-pixel SP1 and the second sub-pixel signal to the second sub-pixel SP2. The signal output circuit 21b and the first sub-pixel SP1 and second sub-pixel SP2 are electrically connected via a plurality of signal lines Lb extending along the second direction D2.

[0033] The scanning circuit 21c scans the first sub-pixel SP1 and the second sub-pixel SP2 in synchronization with the output of the first sub-pixel signal and the second sub-pixel signal by the signal output circuit 21b. The scanning circuit 21c and the first sub-pixel SP1 and the second sub-pixel SP2 are electrically connected via a plurality of scan lines Lc extending along the first direction D1.

[0034] In a plan view, the region demarcated by two adjacent signal lines Lb in the first direction D1 and two adjacent scan lines Lc in the second direction D2 corresponds to either the first subpixel SP1 or the second subpixel SP2.

[0035] A switching element SW is composed of, for example, a thin-film transistor (TFT). In a switching element SW, the source electrode and the signal line Lb are electrically connected, and the gate electrode and the scan line Lc are electrically connected.

[0036] The sub-pixel electrode PE is connected to the drain electrode of the switching element SW. Multiple common electrodes CE are arranged to correspond to multiple scan lines Lc. Both the sub-pixel electrode PE and the common electrode CE are translucent.

[0037] The liquid crystal capacitance LC is the capacitive component of the liquid crystal material in the liquid crystal layer 23, which will be described later, located between the sub-pixel electrode PE and the common electrode CE. The retained capacitance CS is located between the electrode at the same potential as the common electrode CE and the electrode at the same potential as the sub-pixel electrode PE.

[0038] Figure 7 is a cross-sectional view of the display panel 20 shown in Figure 3. The display panel 20 further comprises a first substrate 22, a liquid crystal layer 23, and a second substrate 24. The first substrate 22, the liquid crystal layer 23, and the second substrate 24 are all translucent and are arranged in this order along the third direction D3 from the -D3 side to the +D3 side. The first substrate 22 and the second substrate 24 are rectangular in plan view. However, the plan view shape of the first substrate 22 and the second substrate 24 may be a shape other than rectangular, such as a circle or a trapezoid.

[0039] A common electrode CE is placed on the main surface 22a of the first substrate 22 on the +D3 side. An insulating layer IL is placed on the +D3 side of the common electrode CE, and furthermore, a sub-pixel electrode PE and an alignment film AL are placed thereon.

[0040] The sub-pixel electrode PE is positioned between the insulating layer IL and the alignment layer AL. Thus, the common electrode CE and the sub-pixel electrode PE are positioned on the first substrate 22. In other words, the display panel 20 is a transverse electric field type liquid crystal display.

[0041] The second substrate 24 is located on the +D3 side of the first substrate 22. On the lower surface 24b side of the second substrate 24, the overcoat layer OC, the first color filter CF1, the second color filter CF2, the light-shielding film SM, and the alignment film AL are arranged. The light-shielding film SM, the first color filter CF1, the second color filter CF2, and the overcoat layer OC are arranged between the second substrate 24 and the alignment film AL.

[0042] The overcoat layer OC is formed from a translucent material.

[0043] The first color filter CF1 and the second color filter CF2 are placed between the second substrate 24 and the liquid crystal layer 23. The first color filter CF1 is a color filter included in the first sub-pixel SP1. The second color filter CF2 is a color filter included in the second sub-pixel SP2.

[0044] The first color filter CF1 and the second color filter CF2 are rectangular in plan view. The first color filter CF1 and the second color filter CF2 are light-transmitting, and the peaks of the spectrum of the light they transmit are predetermined. These spectral peaks correspond to the colors of the first color filter CF1 and the second color filter CF2. In other words, the light transmitted through the first color filter CF1 and the second color filter CF2 is colored. Note that the plan view shapes of the first color filter CF1 and the second color filter CF2 may be changed to match the shapes of the first sub-pixel SP1 and the second sub-pixel SP2.

[0045] The color of the first color filter CF1 is the same as the color of the first sub-pixel SP1. The color of the second color filter CF2 is the same as the color of the second sub-pixel SP2. In other words, the first red sub-pixel SP1a has a red first color filter CF1, the second green sub-pixel SP1b has a green first color filter CF1, and the third blue sub-pixel SP1c has a blue first color filter CF1. Also, the first red sub-pixel SP2a has a red second color filter CF2, the second green sub-pixel SP2b has a green second color filter CF2, and the third blue sub-pixel SP2c has a blue second color filter CF2.

[0046] The light-shielding film SM has light-shielding properties and, in a plan view, overlaps with the boundaries of the first sub-pixel SP1 and the second sub-pixel SP2 that are adjacent to each other in the first direction D1 and the second direction D2. That is, the light-shielding film SM overlaps with the signal line Lb and the scan line Lc in a plan view. Note that the signal line Lb and the scan line Lc are not shown in Figure 7. The signal line Lb and the scan line Lc are located on the main surface 22a of the first substrate 22. Also, in Figure 5, the solid lines that demarcate the first sub-pixel SP1 and the second sub-pixel SP2 correspond to the light-shielding film SM. Furthermore, the periphery of the first color filter CF1 and the periphery of the second color filter CF2 overlap with the light-shielding film SM in a plan view.

[0047] As shown in Figure 7, the liquid crystal layer 23 is located between the first substrate 22 and the second substrate 24. The liquid crystal layer 23 contains multiple liquid crystal molecules LM. In a plan view, the liquid crystal layer 23 overlaps with the display area DA. Specifically, the liquid crystal layer 23 is located between two opposing alignment films AL. The initial orientation of the liquid crystal molecules LM is determined by the two opposing alignment films AL.

[0048] The display panel 20 further includes a first polarizing plate 25, a second polarizing plate 26, and a parallax barrier 27.

[0049] The first polarizing plate 25 is positioned on the lower surface 22b of the first substrate 22. The first polarizing plate 25 has a transmission axis perpendicular to the third direction D3. The second polarizing plate 26 is positioned on the upper surface 24a of the second substrate 24. The second polarizing plate 26 has a transmission axis perpendicular to the transmission axis of the first polarizing plate 25 and the third direction D3. The upper surface of the second polarizing plate 26 corresponds to the display surface 10a.

[0050] The parallax barrier 27 is positioned between the second substrate 24 and the second polarizing plate 26. The parallax barrier 27 is plate-shaped. On the second substrate 24, the parallax barrier 27 is positioned on the side opposite to the surface (top surface 24a) facing the first color filter CF1 and the second color filter CF2 (bottom surface 24b). The parallax barrier 27 has a plurality of openings 27a and light-shielding portions 27b.

[0051] The aperture 27a allows light that has passed through the first color filter CF1 to pass through along the first emission direction W1. The first emission direction W1 is shown by a solid line in Figure 7 and is a direction inclined from the third direction D3 toward -D1. The first emission direction W1 is perpendicular to the second direction D2. The first emission direction W1 is the direction toward the light-transmitting body 2 (see Figure 1).

[0052] Furthermore, the aperture 27a allows light that has passed through the second color filter CF2 to pass through, specifically light that travels along the second emission direction W2, which is different from the first emission direction W1. The second emission direction W2 is shown by a dashed line in Figure 7 and is a direction inclined toward +D1 from the third direction D3. The second emission direction W2 is perpendicular to the second direction D2. The first angle θ1 between the first emission direction W1 and the third direction D3 is different from the second angle θ2 between the second emission direction W2 and the third direction D3.

[0053] Figure 8 is a plan view of the parallax barrier 27 shown in Figure 7. In Figure 8, the first sub-pixel SP1 and the second sub-pixel SP2 are shown by dashed lines. As shown in Figures 7 and 8, the multiple apertures 27a overlap in plan view with the first color filter CF1 of the first sub-pixel SP1 and the second color filter CF2 of the second pixel P2, which are adjacent to each other in the row direction. In the plan view shown in Figure 8, the multiple apertures 27a overlap with the -D1 side of the first color filter CF1 and the +D1 side of the second color filter CF2, respectively.

[0054] Furthermore, as shown in Figure 8, the multiple openings 27a are arranged along the row direction in a plan view. In addition, the multiple openings 27a are arranged in a zigzag pattern along the column direction in a plan view.

[0055] The light-shielding portion 27b shown in Figures 7 and 8 is made of a material with high light absorption (for example, metallic chromium (Cr), chromium oxide (CrO2), resin, etc.). The light-shielding portion 27b blocks the light that travels along the second emission direction W2 from the light transmitted through the first color filter CF1. In addition, the light-shielding portion 27b blocks the light that travels along the first emission direction W1 from the light transmitted through the second color filter CF2.

[0056] Furthermore, as shown in Figure 3, the first substrate 22 has an exposed portion E that is exposed from the second substrate 24 in a plan view. The exposed portion E is located on the -D2 side of the second substrate 24 in a plan view. An IC chip Ti including the drive circuit 21 is placed on the upper surface of the exposed portion E. The upper surface of the exposed portion E is part of the main surface 22a of the first substrate 22.

[0057] As shown in Figure 4, the light source device 30 is located on the -D3 side of the display panel 20. The light source device 30 emits light toward the display panel 20. The light source device 30 is, for example, a direct-lit backlight and has multiple light-emitting diodes (not shown).

[0058] Next, the operation of the liquid crystal display device 10 when the first image G1 and the second image G2 are displayed in the display area DA will be described.

[0059] When the liquid crystal display device 10 acquires an image signal transmitted from an external device, it displays the first image G1 and the second image G2 in the display area DA. The image signal includes the gradation of the first sub-pixel SP1 corresponding to the first image G1, and the gradation of the second sub-pixel SP2 corresponding to the second image G2. As described above, the first sub-pixel signal indicating the gradation of the first sub-pixel SP1 is output to the first sub-pixel SP1, and the second sub-pixel signal indicating the gradation of the second sub-pixel SP2 is output to the second sub-pixel SP2.

[0060] A voltage corresponding to the grayscale indicated by the first sub-pixel signal is applied to the liquid crystal layer 23 corresponding to the first sub-pixel SP1, causing the liquid crystal molecules LM to tilt. The degree of tilt of the liquid crystal molecules LM changes according to the grayscale indicated by the first sub-pixel signal. The light from the light source 30 that passes through the liquid crystal layer 23 corresponding to the first sub-pixel SP1 is modulated to the grayscale indicated by the first sub-pixel signal. Furthermore, the light that has passed through the liquid crystal layer 23 corresponding to the first sub-pixel SP1 is colored by passing through the first color filter CF1. The light that has passed through the display panel 20 via the first color filter CF1 corresponds to the first image G1.

[0061] Of the light transmitted through the first color filter CF1, the light traveling along the second emission direction W2 is blocked by the light-shielding portion 27b. Therefore, of the light transmitted through the first color filter CF1, the light traveling along the second emission direction W2 is invisible.

[0062] On the other hand, the light that travels along the first emission direction W1 from the light transmitted through the first color filter CF1 (hereinafter referred to as the first light L1: see Figure 1) passes through the opening 27a of the parallax barrier 27 and is emitted to the outside from the display surface 10a. In other words, the first light L1 is visible as the first image G1.

[0063] Furthermore, a voltage corresponding to the gradation indicated by the second sub-pixel signal is applied to the liquid crystal layer 23 corresponding to the second sub-pixel SP2, causing the liquid crystal molecules LM to tilt. The degree of tilt of the liquid crystal molecules LM changes according to the gradation indicated by the second sub-pixel signal. Light transmitted through the liquid crystal layer 23 corresponding to the second sub-pixel SP2 is modulated to the gradation indicated by the second sub-pixel signal. In addition, the light transmitted through the liquid crystal layer 23 corresponding to the second sub-pixel SP2 is colored by passing through the second color filter CF2. The light transmitted through the display panel 20 via the second color filter CF2 corresponds to the second image G2.

[0064] Of the light transmitted through the second color filter CF2, the light traveling along the first emission direction W1 is blocked by the light-shielding portion 27b. Therefore, of the light transmitted through the second color filter CF2, the light traveling along the first emission direction W1 is invisible.

[0065] On the other hand, the light that travels along the second emission direction W2 from the light transmitted through the second color filter CF2 (hereinafter referred to as the second light L2: see Figure 1) passes through the opening 27a of the parallax barrier 27 and is emitted to the outside from the display surface 10a. In other words, the second light L2 is visible as the second image G2.

[0066] Thus, the parallax barrier 27 causes the viewing angles of the first image G1 and the second image G2 to be different from each other. Furthermore, as described above, the first sub-pixel SP1 and the second sub-pixel SP2 are arranged across the entire display area DA. Therefore, the first image G1 corresponding to the first light L1 and the second image G2 corresponding to the second light L2 are simultaneously displayed across the entire display area DA of the display surface 10a.

[0067] As shown in Figure 1, the first light L1 emitted from the display surface 10a travels toward the transparent material 2 along the first emission direction W1 and is projected by the transparent material 2. An observer who directs their line of sight Lv toward the first light L1 projected onto the transparent material 2 perceives the first image G1 as the first virtual image VG1.

[0068] The first virtual image VG1 is perceived by the observer in a state that is nearly perpendicular to the observer's line of sight Lv. The observer's line of sight Lv is nearly parallel to the X direction. The first virtual image VG1 is perpendicular to the X direction. The first image G1 displayed on the display surface 10a and the first virtual image VG1 are symmetrical with respect to the transparent material 2 as the axis of symmetry. In other words, the degree of inclination of the transparent material 2, the degree of inclination of the display surface 10a, and the first angle θ1 are determined so that the first virtual image VG1 is perceived in a state that is perpendicular to the X direction.

[0069] Meanwhile, the second light L2 emitted from the display surface 10a is incident on the reflector 40.

[0070] The reflector 40 is, for example, a mirror. The reflector 40 has a reflective surface 41 to which the second light L2 emitted from the display surface 10a of the liquid crystal display device 10 is incident. The reflective surface 41 reflects the second light L2 toward the translucent body 2 along the first emission direction W1. In other words, the second angle θ2 and the degree of inclination (orientation) of the reflector 40 are determined so that the second light L2 reflected by the reflective surface 41 travels toward the translucent body 2 along the first emission direction W1.

[0071] The second light L2 reflected by the reflector 40 travels along the first emission direction W1 and is projected by the translucent body 2. An observer who directs their line of sight Lv towards the second light L2 projected onto the translucent body 2 perceives the second image G2 as the second virtual image VG2. The second virtual image VG2 is perceived by the observer as being adjacent to the first virtual image VG1 without overlapping. Furthermore, the second virtual image VG2 is perceived by the observer at an angle to the first virtual image VG1.

[0072] If we define the virtual image TG as the image that is line-symmetric to the second image G2 displayed on the display surface 10a with respect to the reflective surface 41 as the axis of symmetry, then the second virtual image VG2 and the virtual image TG are line-symmetric with respect to the transparent material 2 as the axis of symmetry. Furthermore, the virtual image TG is tilted with respect to the second virtual image VG2 displayed on the display surface 10a. Therefore, the second virtual image VG2 is tilted with respect to the first virtual image VG1.

[0073] Figure 9 shows the first virtual image VG1 and the second virtual image VG2 as viewed by the observer in the head-up display 1 shown in Figure 1. In the example shown in Figure 9, the first image G1 includes letters and symbols indicating the vehicle's speed and speed limit. The second image G2 includes an arrow indicating the direction of travel of the vehicle and a straight line indicating the roadway.

[0074] The first virtual image VG1, corresponding to the first image G1, is perceived by the observer in a state that is almost perpendicular to the observer's line of sight Lv, as described above. Therefore, the observer can properly perceive the letters and symbols indicating the vehicle's speed and speed limit.

[0075] On the other hand, the second virtual image VG2, which corresponds to the second image G2, is perceived by the observer at an angle relative to the first virtual image VG1, as described above. As a result, the arrow indicating the direction of travel of the vehicle and the straight line indicating the roadway, which are included in the second virtual image VG2, are perceived by the observer with depth. Therefore, the observer can appropriately determine the direction of travel of the vehicle based on the second virtual image VG2.

[0076] Thus, the HUD1 emits a first light L1 and a second light L2 from a planar display surface 10a in different directions, allowing the observer to see a first virtual image VG1 and a second virtual image VG2 with different degrees of inclination. Therefore, the HUD1 can be made smaller than when multiple display surfaces with different degrees of inclination are used to allow the observer to see a first virtual image VG1 and a second virtual image VG2 with different degrees of inclination.

[0077] <Second Embodiment> Next, the differences between the HUD1 of the second embodiment of this disclosure and the HUD1 of the first embodiment described above will be explained.

[0078] Figure 10 is a schematic diagram of a head-up display 1 according to the second embodiment of this disclosure. In the HUD 1 of this second embodiment, the first angle θ1 between the third direction D3 and the first emission direction W1 and the second angle θ2 between the third direction D3 and the second emission direction W2 are equal to each other. Furthermore, the reflector 40 is positioned such that the reflective surface 41 is perpendicular to the display surface 10a (parallel to the third direction D3).

[0079] In this case, the virtual image TG is parallel to the second image G2 displayed on the display surface 10a. As described above, the second virtual image VG2 and the virtual image TG are symmetrical with respect to the transparent material 2 as the axis of symmetry. Also, the first image G1 and the first virtual image VG1 displayed on the display surface 10a are symmetrical with respect to the transparent material 2 as the axis of symmetry. Therefore, the degree of inclination of the first virtual image VG1 and the degree of inclination of the second virtual image VG2 are equal. Furthermore, similar to the first embodiment described above, the second virtual image VG2 is visible to the observer in a state where it is adjacent to the first virtual image VG1 without overlapping with it.

[0080] Thus, in the HUD1 of this second embodiment, a first light L1 and a second light L2 are emitted from one display surface 10a, and the first virtual image VG1 and the second virtual image VG2 are visible to the observer in a state where they have the same degree of inclination and are adjacent to each other.

[0081] HUD1 allows the virtual image to be viewed over a wider area than when light is emitted from a single display surface 10a in only one direction (for example, the first emission direction W1) and not in two directions, and a virtual image corresponding to that light is visible.

[0082] <Third Embodiment> Next, the differences between the HUD1 of the third embodiment of this disclosure and the HUD1 of the first embodiment described above will be explained.

[0083] Figure 11 is a schematic diagram of a head-up display 1 according to the third embodiment of this disclosure. In the HUD 1 of this third embodiment, the first angle θ1 between the first emission direction W1 and the third direction D3 and the second angle θ2 between the second emission direction W2 and the third direction D3 are equal to each other.

[0084] Figure 12 is a cross-sectional view of the display panel 20 of the liquid crystal display device 10 shown in Figure 11. In this third embodiment, the liquid crystal display device 10 includes a reflective polarizing plate 228 instead of the second polarizing plate 26 of the first embodiment described above. The upper surface 228a of the reflective polarizing plate 228 corresponds to the display surface 10a.

[0085] The reflective polarizer 228 has a polarization axis that transmits linearly polarized light having a first polarization direction. The polarization axis of the reflective polarizer 228 is parallel to the transmission axis of the second polarizer 26 in the first embodiment described above. The first light L1 and the second light L2 emitted from the display surface 10a are transmitted through the polarization axis of the reflective polarizer 228. In other words, the first light L1 and the second light L2 emitted from the display surface 10a are linearly polarized light having a first polarization direction parallel to the polarization axis of the reflective polarizer 228. The first polarization direction is orthogonal to the first emission direction W1 and the second emission direction W2. In Figure 11, the symbols indicating the first light L1 and the second light L2 having the first polarization direction are "L1(S)" and "L2(S)".

[0086] Furthermore, the upper surface 228a of the reflective polarizer 228 reflects linearly polarized light having a second polarization direction perpendicular to the first polarization direction. The second polarization direction is perpendicular to both the first emission direction W1 and the second emission direction W2.

[0087] As shown in Figure 11, the reflector 40 is positioned so that the reflective surface 41 and the display surface 10a face each other, and the reflective surface 41 is perpendicular to the second emission direction W2. As a result, the second light L2 incident on the reflector 40 is reflected by the reflective surface 41 toward the display surface 10a of the liquid crystal display device 10 along the second emission direction W2.

[0088] Furthermore, a quarter-wavelength phase difference plate 242 is placed on the reflective surface 41 of the reflector 40. Light transmitted through the quarter-wavelength phase difference plate 242 is given a phase difference of 1 / 4 wavelength.

[0089] Figure 13 shows the quarter phase difference plate 242 shown in Figure 11 as viewed from a direction perpendicular to the reflective surface 41. The leading axis 242a and the lagging axis 242b of the quarter phase difference plate 242 are tilted at 45° with respect to the second polarization direction.

[0090] As shown in Figure 11, in this third embodiment, the first light L1 travels toward the transparent body 2 along the first emission direction W1, similar to the first embodiment, and is projected by the transparent body 2. The first virtual image VG1 is perpendicular to the X direction.

[0091] In this third embodiment, the second light L2 emitted from the display surface 10a travels along the second emission direction W2 and is incident on the quarter-wavelength phase difference plate 242 of the reflector 40. The second light L2 is given a phase difference of 1 / 4 wavelength by the quarter-wavelength phase difference plate 242 and is reflected by the reflector surface 41. The second light L2 reflected by the reflector surface 41 is incident on the quarter-wavelength phase difference plate 242, and a phase difference of another 1 / 4 wavelength is further added. In other words, the second light L2 emitted from the display surface 10a is given a phase difference of 1 / 2 wavelength (= 2 × (1 / 4 wavelength)) by being reflected by the reflector 40.

[0092] As described above, the second light L2 emitted from the display surface 10a is linearly polarized with a first polarization direction. Therefore, the second light L2 reflected by the reflector 40 is linearly polarized with a second polarization direction perpendicular to the first polarization direction. In Figure 11, the symbol indicating the second light L2 with the second polarization direction is "L2(P)".

[0093] Furthermore, as described above, the reflective surface 41 is perpendicular to the second emission direction W2. Therefore, the second light L2 reflected by the reflector 40 travels along the second emission direction W2. Thus, the reflector 40 has a reflective surface 41 that reflects light transmitted through the 1 / 4 phase difference plate 242 towards the display surface 10a along the second emission direction W2.

[0094] The second light L2 reflected by the reflector 40 is incident on the upper surface 228a of the reflective polarizer 228 along the second emission direction W2. The second light L2 incident on the upper surface 228a of the reflective polarizer 228 has a second polarization direction and is reflected by the upper surface 228a of the reflective polarizer 228. Also, the first angle θ1 and the second angle θ2 are equal to each other. Therefore, the second light L2 reflected by the upper surface 228a of the reflective polarizer 228 travels towards the translucent material 2 along the first emission direction W1 and is projected by the translucent material 2.

[0095] If we define the second virtual image TG2 as the image that is line-symmetric to the virtual image TG with respect to the display surface 10a as the axis of symmetry, then the second virtual image VG2 and the second virtual image TG2 are line-symmetric with respect to the transparent material 2 as the axis of symmetry. As a result, the second virtual image VG2 is tilted with respect to the first virtual image VG1.

[0096] Furthermore, the second virtual image VG2 is projected by the transparent body 2 from the second light L2 reflected by the upper surface 228a of the reflective polarizer 228. Therefore, the observer sees the second virtual image VG2 overlapping with the first virtual image VG1. Moreover, the optical path length of the second light L2 is longer than the optical path length of the first light L1. Consequently, the second virtual image VG2 is located on the -X side of the first virtual image VG1.

[0097] Figure 14 shows the first virtual image VG1 and the second virtual image VG2 as viewed by the observer in the head-up display 1 shown in Figure 1.

[0098] In the example shown in Figure 14, the first image G1 includes letters and symbols indicating the vehicle's speed and speed limit, as well as an arrow indicating the vehicle's direction of travel. The second image G2 also includes an arrow indicating the vehicle's direction of travel. The arrows indicating the vehicle's direction of travel in the first virtual image VG1 and the arrows indicating the vehicle's direction of travel in the second virtual image VG2 are positioned so that they do not overlap and are not visible to the observer.

[0099] The second virtual image VG2 is inclined relative to the first virtual image VG1, and the observer perceives the second virtual image VG2 as having depth relative to the first virtual image VG1. Therefore, the observer perceives the arrow indicating the direction of travel of the vehicle in the second virtual image VG2 as being further forward in the direction of travel than the arrow indicating the direction of travel of the vehicle in the first virtual image VG1. Thus, the observer can appropriately determine the direction of travel of the vehicle based on the first virtual image VG1 and the second virtual image VG2.

[0100] <Variation> While preferred embodiments of this disclosure have been described above, this disclosure is not limited to such embodiments. The content disclosed in the embodiments is merely an example, and various modifications are possible without departing from the spirit of this disclosure. Any modifications made without departing from the spirit of this disclosure will naturally fall within the technical scope of this disclosure.

[0101] For example, the liquid crystal display device 10 may be arranged in a state where the third direction D3 and the Z direction are tilted. In this case, the first virtual image VG1 does not have to be orthogonal to the X direction.

[0102] Furthermore, the aperture 27a does not need to overlap with at least one of the first color filter CF1 and the second color filter CF2 in a plan view.

[0103] Figure 15 shows the arrangement of the first sub-pixel SP1 and the second sub-pixel SP2 in the liquid crystal display device 10 of the head-up display 1 according to a modified embodiment of the present disclosure.

[0104] In this modified example, the first pixel P1 and the second pixel P2 are arranged along the row direction (first direction D1) and the column direction (second direction D2), respectively. Focusing on the first pixel P1 in the row direction, the first sub-pixel SP1a, the third sub-pixel SP1c, and the second sub-pixel SP1b are repeatedly arranged in this order. Similarly, focusing on the second pixel P2 in the row direction, the second sub-pixel SP2b, the first sub-pixel SP2a, and the third sub-pixel SP2c are repeatedly arranged in this order.

[0105] Furthermore, the first subpixel SP1 and the second subpixel SP2 are arranged alternately along the row direction. That is, in the row direction, the first subpixel SP1 and the second subpixel SP2 are adjacent to each other. Specifically, in the row direction, the first first subpixel SP1a is adjacent to at least one of the second second subpixel SP2b and the third second subpixel SP2c. Also, in the row direction, the second first subpixel SP1b is adjacent to at least one of the third second subpixel SP2c and the first second subpixel SP2a. Furthermore, in the row direction, the third first subpixel SP1c is adjacent to at least one of the first second subpixel SP2a and the second second subpixel SP2b.

[0106] Furthermore, in the row direction, the first second subpixel SP2a is adjacent to at least one of the second first subpixel SP1b and the third first subpixel SP1c. Also, in the row direction, the second second subpixel SP2b is adjacent to at least one of the third first subpixel SP1c and the first first subpixel SP1a. Moreover, in the row direction, the third second subpixel SP2c is adjacent to at least one of the first first subpixel SP1a and the second first subpixel SP1b.

[0107] Furthermore, multiple first subpixels SP1 are arranged along the column direction. Specifically, multiple first subpixels SP1a are arranged adjacent to each other along the column direction. Multiple second subpixels SP1b are arranged adjacent to each other along the column direction. Multiple third subpixels SP1c are arranged adjacent to each other along the column direction.

[0108] Furthermore, multiple second subpixels SP2 are arranged along the column direction. Specifically, multiple first second subpixels SP2a are arranged adjacent to each other along the column direction. Multiple second second subpixels SP2b are arranged adjacent to each other along the column direction. Multiple third second subpixels SP2c are arranged adjacent to each other along the column direction.

[0109] Figure 16 is a plan view of a parallax barrier 327 in a liquid crystal display device 10 provided in a modified head-up display 1 according to an embodiment of the present disclosure. The parallax barrier 327 in this modified embodiment corresponds to the arrangement of the first sub-pixel SP1 and the second sub-pixel SP2 shown in Figure 15. The parallax barrier 327 has an opening 327a and a light-shielding portion 327b.

[0110] In Figure 16, the first sub-pixel SP1 and the second sub-pixel SP2 are shown by dashed lines. In this modified example, each of the multiple apertures 327a overlaps in plan view with one first color filter CF1 and one second color filter CF2 that are adjacent to each other in the row direction. In the plan view shown in Figure 16, similar to the embodiment described above, each of the multiple apertures 327a overlaps with the -D1 side of the first color filter CF1 and the +D1 side of the second color filter CF2, respectively.

[0111] The aperture 327a has a shape that extends along the column direction (second direction D2). Multiple apertures 327a each overlap in a plan view with multiple first subpixels SP1 and multiple second subpixels SP2 arranged along the column direction. Multiple apertures 327a are arranged along the row direction (first direction D1).

[0112] As shown in Figures 15 and 16, the arrangement of the first sub-pixel SP1, the second sub-pixel SP2, and the aperture 327a results in different viewing angles for the first image G1 and the second image G2, similar to the embodiments described above. In this modified example, the first sub-pixel SP1 and the second sub-pixel SP2 are also arranged across the entire display area DA. Therefore, the first image G1 and the second image G2 are displayed simultaneously across the entire display area DA.

[0113] In the parallax barrier 327 shown in Figure 16, the aperture 327a may be formed so as to overlap with one first subpixel SP1 and one second subpixel SP2 in a plan view in the column direction. In this case, multiple apertures 327a are arranged along the row direction (first direction D1) and the column direction (second direction D2), respectively.

[0114] Furthermore, any other effects and advantages brought about by the embodiments described herein that are obvious from the description herein or that can be appropriately conceived by a person skilled in the art are naturally provided for by this disclosure. [Explanation of Symbols]

[0115] 1. Head-Up Display (HUD) 2 Translucent body 10 LCD display device 10a Display surface 27 Parallax Barrier 40 Reflector 41 Reflective surface 228 Reflective polarizing plate 242 1 / 4 retardation plate D1 1st direction D2 2nd direction D3 Third direction (orthogonal direction) DA display area G1 Image 1 G2 Image 2 L1 1st light L2 2nd light Lv line of sight P pixels P1: First pixel P2 2nd pixel SP1 First subpixel SP2 2nd subpixel W1 1st emission direction W2 Second exit direction θ1 1st angle θ2 2nd angle

Claims

1. A liquid crystal display device that emits a first light corresponding to a first image from the display surface toward a translucent material along a first emission direction, and emits a second light corresponding to a second image from the display surface along a second emission direction different from the first emission direction, The device comprises a reflector having a reflective surface that receives the second light and reflects the second light toward the light-transmitting body along the first emission direction, Head-up display.

2. The first angle between the orthogonal direction perpendicular to the display surface and the first emission direction, and the second angle between the orthogonal direction and the second emission direction are equal to each other. The display surface and the reflective surface are orthogonal to each other. The head-up display according to claim 1.

3. The aforementioned liquid crystal display device is A display panel having multiple pixels arranged in a matrix in a planar view, The device comprises a light source that emits light toward the display panel, The aforementioned pixel has a first pixel corresponding to the first image and a second pixel corresponding to the second image. The first pixel includes a plurality of first subpixels, The aforementioned second pixel includes a plurality of second subpixels, The aforementioned display panel is The light from the light source that has passed through the first sub-pixel and is traveling along the first emission direction is allowed to pass through, and the light from the light source that has passed through the second sub-pixel and is traveling along the second emission direction is allowed to pass through, The present invention further comprises a parallax barrier that blocks the light from the light source that has passed through the first sub-pixel and travels along the second emission direction, and the light from the light source that has passed through the second sub-pixel and travels along the first emission direction. The head-up display according to claim 1.

4. A liquid crystal display device that emits a first light corresponding to a first image from the display surface toward a translucent material along a first emission direction, and emits a second light corresponding to a second image from the display surface along a second emission direction different from the first emission direction, A 1 / 4 phase difference plate into which the second light emitted from the display surface is incident, The system includes a reflector having a reflective surface that reflects light transmitted through the 1 / 4 phase difference plate toward the display surface along the second emission direction, The first angle between the orthogonal direction perpendicular to the display surface and the first emission direction, and the second angle between the orthogonal direction and the second emission direction are equal to each other. The liquid crystal display device includes a reflective polarizing plate that allows linearly polarized light having a first polarization direction to pass through and reflects linearly polarized light having a second polarization direction perpendicular to the first polarization direction. Head-up display.

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