JP6933002B2 - Display device - Google Patents

Description

The present invention relates to a display device for a vehicle provided with a display panel (such as a liquid crystal display panel) for displaying an image.

Conventionally, as a display device of this type, for example, one described in Patent Document 1 below is known. The display device described in Patent Document 1 comprises a vehicle instrument mounted on a vehicle, and has a liquid crystal display panel having a rectangular display element provided with a display area capable of displaying predetermined information, and the liquid crystal display panel. The display board arranged on the front side of the liquid crystal display panel so as to cover the liquid crystal display panel is joined by a translucent spacer filled in the gap formed between the liquid crystal display panel and the display board. ..

In this case, the display board is made of a transparent synthetic resin material, and the front side thereof is provided with index parts such as scales and characters constituting the speedometer so that it can be used for a vehicle instrument. On the surface of the display board facing the liquid crystal display panel, a frame-shaped light-shielding layer that does not transmit light is formed so as to correspond to an area outside the display area. Therefore, when the display device is viewed straight from the viewer side, the viewer can see through the predetermined information through the perspective portion area of the display plate on which the light-shielding layer is not formed.

Further, as a display board of this type, for example, those described in Patent Document 2 below are known. The display board described in Patent Document 2 is a so-called squeeze display board that is squeezed into a three-dimensional shape by applying compressed air to a flat plate-shaped display board heated by a heating member (hot plate pressure-pneumatic molding).

Japanese Unexamined Patent Publication No. 2014-202685 Japanese Unexamined Patent Publication No. 2004-181639

However, in such a drawing display board, the refractive index is irregular due to the orientation of the molecular chains developed by hot plate pressure air forming and the residual strain due to quenching during molding, especially in the vicinity of the part drawn into a three-dimensional shape. And a phenomenon having optical anisotropy occurs. When the transparent portion area is provided in the portion having the optical anisotropy, the linearly polarized light of the longitudinal wave component of the liquid crystal display panel is refracted to become the linearly polarized light in which the longitudinal wave and the transverse wave component are mixed. When the viewer visually recognizes with polarized sunglasses, polarized sunglasses generally cut the linearly polarized light of the transverse wave component, so that the portion of the display plate having optical anisotropy is visually recognized as a rainbow-colored shadow, and the predetermined information is displayed. There was a risk that visibility would decrease.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a display device having good visibility even when visually recognizing through polarized sunglasses.

In the present invention, a liquid crystal display panel 51 provided with a display area 51d capable of displaying predetermined information as an image and having a biased member 51b attached to the front side, and the liquid crystal display panel on the front side of the liquid crystal display panel 51. In a display device including a display plate 40 covering the 51, the display plate 40 is optically anisotropic to a portion in which the three-dimensionally shaped narrowing portion 49 and the display area 51d around the narrowing portion 49 are visually recognized. A retardation plate 90 having a portion R and arranged between the liquid crystal display panel 51 and the display plate 40 so that the crystal axis J2 differs from the absorption axis J1 of the polarizing member 51b by about 45 degrees. It is characterized by having.

Further, the present invention is characterized in that the throttle portion 49 is formed into a protruding shape in cross section .

Further, the present invention is characterized by having a first transparent resin layer 81 that is filled between the display plate 40 and the retardation plate 90 and joins the display plate 40 and the retardation plate 90. do.

Further, the present invention has a second transparent resin layer 82 that is filled between the retardation plate 90 and the liquid crystal display panel 51 and joins the retardation plate 90 and the liquid crystal display panel 51. It is a feature.

Further, the present invention is characterized in that the area of the first transparent resin layer 81 or the second transparent resin layer 82 in the surface direction is smaller than the area of the retardation plate 90 in the surface direction.

According to the display device according to the present invention, the linearly polarized light of the liquid crystal display panel becomes circularly polarized light by passing through the retardation plate, so that the portion of the display plate having optical anisotropy is not affected by the polarized sunglasses. Therefore, it is possible to provide a display device having good visibility.

The front view which shows the embodiment of this invention. A cross-sectional view taken along the line AA in FIG. FIG. 2 is an enlarged cross-sectional view showing details of part B in FIG. The front view which shows the absorption axis J1 of the front side polarizing plate 51b. The front view which shows the crystal axis J2 of the retardation plate 90. The front view which shows the absorption axis J3 of polarized sunglasses G.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 6. Further, the front-rear direction and the XY direction of the display device are indicated by arrows in each figure. The display device for a vehicle includes a pointer 10, a circuit board 20, a case body 30, a display board 40, a liquid crystal display 50, and a rear cover 60.

The pointer 10 includes an indicator portion 11 made of a translucent resin, a pointer cap 12 made of an opaque resin, a boss portion 13 into which the rotation shaft 22a of the pointer drive portion 22 described later is press-fitted, and the indicator portion 11. It has a pointer seat 14 to be placed, and an index unit 41, which will be described later, is instructed by the instruction unit 11. The boss portion 13 and the pointer seat 14 are integrally formed of white resin. The illumination light emitted from the light emitting element 25 mounted on the front side of the circuit board 20 passes through the through hole 40c and is reflected by the boss portion 13 in the vicinity of the through hole 40c of the display plate 40.

The circuit board 20 includes a board main body 21, a pointer driving unit 22 mounted on the rear surface side of the board main body 21, and a plurality of light emitting elements 24 and 25 mounted on the front surface side of the board main body 21. It is arranged behind the display board 40.

The substrate main body 21 is a rigid plate-shaped glass epoxy-based substrate on which a drive circuit (not shown) for driving the pointer drive unit 22, a light emitting circuit (not shown) for causing the light emitting elements 24 and 25 to emit light, and the like are formed. It consists of a printed circuit board. The drive circuit and the light emitting circuit are each composed of a wiring pattern, a resistor, a capacitor, and the like. The drive circuit drives the pointer drive unit 22 based on the control signal supplied from the control unit. The light emitting circuit causes the light emitting elements 24 and 25 to emit light based on the control signal supplied from the control unit.

The pointer drive unit 22 includes a movable magnet type drive device, a stepping motor, and the like. The rotation shaft 22a of the pointer drive unit 22 is inserted into a through hole 21a formed in the substrate main body 21, and the pointer 10 is attached to the rotation shaft 22a. The boss portion 13 is inserted into the through hole 40c formed in the display plate 40. The through hole 40c of the display plate 40 is formed at a position corresponding to the rotation shaft 22a, and has a circular shape when viewed from the front.

The drive circuit of the board body 21 drives the pointer drive unit 22 based on the control signal supplied from the control unit. The rotation shaft 22a rotates at a rotation angle according to the control signal. As a result, the pointer 10 rotates at a predetermined rotation angle according to the vehicle speed, and the instruction unit 11 instructs the index unit 41, which will be described later.

The light emitting elements 24 and 25 are each composed of one or more light emitting diodes and the like. The light emitting element 24 transmits and illuminates the display plate 40. The light emitting element 25 makes the indicator 11 shine. The light emitting elements 24 and 25 are driven based on a control signal supplied from the control unit, and are turned on / off according to an illumination switch or the like operated by the vehicle driver.

The case body 30 is made of a white synthetic resin (for example, polypropylene), and the circuit board 20 is fixed to the case body 30. Further, the case body 30 has a first vertical portion 31, a first inclined portion 32, a parallel portion 33, a second inclined portion 34, and a second vertical portion 35. The first vertical portion 31 has a cylindrical shape, the front end of which is in contact with the rear surface of the display plate 40, and the rear end of which is in contact with the front surface of the circuit board 20. Further, the first vertical portion 31 is a light-shielding wall that prevents the illumination light emitted by the light emitting element 24 and the illumination light emitted by the light emitting element 25 from being mixed.

The first inclined portion 32 has a shape that extends in an inverted conical shape from the outer peripheral surface of the first vertical portion 31. Further, the first inclined portion 32 reflects the illumination light emitted by the light emitting element 24 toward the parallel portion 33 and the second inclined portion 34. The parallel portion 33 has a flat plate shape parallel to the display plate 40. The second inclined portion 34 has an inverted conical shape and is connected to the outer peripheral end of the parallel portion 33. Further, the second inclined portion 34 reflects the illumination light emitted by the light emitting element 24 toward the display plate 40. The second vertical portion 35 has a cylindrical shape, and its rear end is in contact with the front surface of the circuit board 20. Further, the second vertical portion 35 is connected to the outer peripheral end of the second inclined portion 34. Further, the front end of the second vertical portion 35 is in contact with the rear surface of the display plate 40, and the rear end is in contact with the front surface of the circuit board 20.

The display plate 40 has an index unit 41 and a number / unit unit 43 formed of an opening portion of a light-shielding portion 45 of the display plate 40, which will be described later. The index unit 41 is a scale arranged in the vicinity of the number / unit unit 43. Further, the index unit 41 is arranged in an arc shape centered on the through hole 40c, and is transmitted and illuminated by the illumination light emitted by the light emitting element 24.

Further, the display board 40 has a translucent substrate 44, a light-shielding portion 45, and a protective layer 46. The translucent substrate 44 is made of a flat plate-shaped PC (polycarbonate). The light-shielding portion 45 is made of a black printing layer and is formed on the rear surface of the translucent substrate 44. Further, the light-shielding portion 45 has a rectangular window portion 45d. The protective layer 46 is made of a transparent printing layer and is formed on the front surface of the translucent substrate 44.

Further, the display plate 40 has a drawing protrusion 49 whose cross section is formed into a protrusion shape by hot plate compressed air molding so as to surround the outer periphery of the index portion 41 and the number / unit portion 43. As a result, around the diaphragm protrusion 49, the refractive index becomes irregular due to the orientation of the molecular chains developed by hot plate pressure air molding and the residual strain due to quenching during molding, and thus has optical anisotropy. An optically anisotropic portion R is provided at a portion of the portion 45d close to the diaphragm protrusion 49.

The liquid crystal display 50 is arranged between two pointer type instruments (speedometer and tachometer). The front side of the liquid crystal display 50 is covered with a display board 40. The liquid crystal display 50 includes a liquid crystal display panel 51, a backlight unit 52, a light diffusing plate 53, and a case body 54. The liquid crystal display panel 51 has a front polarizing member (polarizing member) 51b attached to the front surface of the TFT type color LCD cell 51a, and a rear polarizing member 51c attached to the rear surface. A displayable display area 51d is provided. The display area 51d is provided so as to be visible to the viewer through the rectangular window portion 45d.

The backlight unit 52 is arranged behind the liquid crystal display panel 51, and transmits and illuminates the liquid crystal display panel 51. The light diffusing plate 53 is arranged between the liquid crystal display panel 51 and the backlight unit 52, and diffuses the illumination light emitted from the backlight unit 52. The case body 54 is made of a metal bottomed housing, and houses a liquid crystal display panel 51, a backlight unit 52, and a light diffusing plate 53.

Between the display plate 40 and the liquid crystal display 50, a first translucent adhesive 81 (first transparent resin layer), a retardation plate 90, and a second translucent adhesive 82 (second transparent). Resin layer) is arranged. The retardation plate 90 has a phase of light polarized in a direction perpendicular to the crystal axis (in the plane of the wave plate), which is 1/4 wavelength (as a phase) of the phase of light polarized in a direction parallel to the crystal axis. Is an optical element that has the function of delaying π / 2).

The first translucent adhesive 81 and the second translucent adhesive 82 are, for example, colorless and transparent sheet-like adhesives. Further, the first translucent adhesive 81 is arranged between the display plate 40 and the retardation plate 90, is in close contact with both, and is attached to the rear surface of the display plate 40 and the front surface of the retardation plate 90. .. Further, the first translucent adhesive 81 covers the window portion 45d of the light-shielding portion 45 and overlaps the light-shielding portion 45. The area of the first translucent adhesive 81 in the surface direction is formed smaller than the area of the retardation plate 90 in the surface direction, and the first translucent adhesive 81 does not protrude from the retardation plate 90. It is pasted like this.

The second translucent adhesive 82 is arranged between the retardation plate 90 and the liquid crystal display panel 51, is in close contact with both, and is on the rear surface of the retardation plate 90 and the front surface of the front polarizing member 51b of the liquid crystal display panel 51. It is pasted. The area of the second translucent adhesive 82 in the surface direction is formed smaller than the area of the retardation plate 90 in the surface direction, and the second translucent adhesive 82 does not protrude from the retardation plate 90. It is pasted like this. Here, the absorption axis J1 of the front polarizing member 51b is set in the X direction (left-right direction) as shown in FIG. 4, and the crystal axis (crystal axis) J2 of the retardation plate 90 is as shown in FIG. , It is arranged in a state of being tilted 45 degrees with respect to the absorption axis J1.

As shown in FIG. 3, a viewer sees an optical path L1 when the light emitted from the liquid crystal display panel 51 does not pass through the optically anisotropic portion R and an optical path L2 when passing through the optically anisotropic portion R. Explains how the viewer sees the display device when the polarized sunglasses G are used. Further, as shown in FIG. 6, since polarized sunglasses G generally cut linearly polarized light (transverse wave component) polarized in the X direction, the absorption axis J3 of the polarized sunglasses G is oriented in the X direction. The case where it is set will be described.

First, in the optical path L1, the light emitted from the liquid crystal display panel 51 becomes linearly polarized light (of the longitudinal wave component) polarized in the Y direction (direction perpendicular to the X direction). Since the second translucent adhesive 82 does not affect the polarization, the light that has passed through the second translucent adhesive 82 remains linearly polarized light that is polarized in the Y direction thereafter. When the crystal axis of the 1/4 wave plate of the retardation plate 90 is set to 45 degrees with respect to linearly polarized light, circularly polarized light is obtained. Therefore, the light passing through the retardation plate 90 is circularly polarized light thereafter. Since the first translucent adhesive 81 does not affect the polarization, the light that has passed through the first translucent adhesive 81 remains circularly polarized. Since the translucent substrate 44 of the display plate 40 does not affect the polarization, the light that has passed through the translucent substrate 44 thereafter remains circularly polarized light.

Polarized sunglasses G cuts linearly polarized light polarized in the X direction (transverse wave component), but does not affect circularly polarized light. The person can visually recognize the vehicle information as an image.

Next, in the optical path L2, the light emitted from the liquid crystal display panel 51 and the light passing through the second translucent adhesive 82 remain linearly polarized light polarized in the Y direction. After that, the light that has passed through the retardation plate 90 becomes circularly polarized light. After that, the light that has passed through the first translucent adhesive 81 remains circularly polarized light. Since the optically anisotropic portion R of the translucent substrate 44 does not affect the circularly polarized light, the light that has passed through the optically anisotropic portion R thereafter remains circularly polarized light. After that, the light that has passed through the polarized sunglasses G also remains circularly polarized, so that the viewer can visually recognize the vehicle information as an image in the same manner as in the optical path L2.

Hereinafter, for comparison, a case where the retardation plate 90 and the second translucent adhesive 82 are not arranged between the display plate 40 and the liquid crystal display 50 will be described. Here, the rear surface of the first translucent adhesive 81 is attached to the liquid crystal display panel 51.

First, in the optical path L1, the light that has passed through the first translucent adhesive 81 and the light that has passed through the translucent substrate 44 remains linearly polarized light that is polarized in the Y direction. The polarized sunglasses G cuts the linearly polarized light polarized in the X direction, but does not affect the linearly polarized light polarized in the Y direction, so that the light passing through the polarized sunglasses G is then polarized in the Y direction. Since the linearly polarized light remains, the viewer can visually recognize the vehicle information as an image.

Next, in the optical path L2, the light that has passed through the first translucent adhesive 81 remains linearly polarized light that is polarized in the Y direction. Since the optically anisotropic portion R of the translucent substrate 44 complexly refracts linearly polarized light, the light that has passed through the optically anisotropic portion R is linearly polarized light that is polarized in the X direction, or in the X and Y directions. It becomes polarized light that is polarized in the middle of. Since the polarized sunglasses G cuts the linearly polarized light polarized in the X direction, the light polarized in the X direction among the light passing through the polarized sunglasses G is visually recognized as a black shadow, and the X direction and the Y are also recognized. Since the polarized light in which the directions are mixed is visually recognized as a rainbow-colored shadow, the viewer cannot visually recognize the vehicle information in the image.

As described in the first embodiment of the present invention, the retardation plate 90 is arranged between the display board 40 and the liquid crystal display 50, so that the linearly polarized light of the liquid crystal display panel 51 causes the retardation plate 90 to move. Since it becomes circularly polarized light by being transmitted, the portion of the display board 40 having the optically anisotropic portion R is not affected by the polarized sunglasses G, and it is possible to provide a display device having good visibility.

Further, a first translucent adhesive 81 is provided between the display plate 40 and the retardation plate 90, and a surface of the second translucent adhesive 82 is provided between the retardation plate 90 and the liquid crystal display panel 51. By arranging them, it is possible to suppress the reflection generated at each interface, suppress the decrease in the display contrast of the liquid crystal display 50, and secure the visibility.

Further, by forming the area of the first translucent adhesive 81 and the second translucent adhesive 82 in the surface direction smaller than the area of the retardation plate 90 in the surface direction, the first translucency is transmitted. It becomes easy to attach the sex adhesive 81 and the second translucent adhesive 82 so as not to protrude from the front and back surfaces of the retardation plate 90, and the productivity can be improved.

Although the display device of the present invention has been described by taking the configuration of the above-described embodiment as an example, the present invention is not limited to this, and other configurations are not deviated from the gist of the present invention. Of course, various improvements and design changes are possible.

The present invention relates to a display device for a vehicle, and can be applied to, for example, a display device for a vehicle mounted on a moving body including an automobile, a motorcycle, or an agricultural machine or a construction machine.

40 Display board 51 Liquid crystal display panel 51b Front polarizing member (polarizing member)
51d Display area 81 Translucent adhesive 81 (first transparent resin layer)
82 Second translucent adhesive 82 (second transparent resin layer)
90 Phase difference plate J1 Absorption shaft (absorption shaft) of front polarizing member 51b
Crystal axis (crystal axis) of J2 retardation plate 90
R Optical anisotropy

Claims (5)

A liquid crystal display panel that has a display area on which predetermined information can be displayed as an image and has a polarizing member attached to the front side.
A display plate that covers the liquid crystal display panel on the front side of the liquid crystal display panel,
In a display device equipped with
The display plate has a three-dimensional diaphragm portion and an optically anisotropic portion at a portion where the display area around the diaphragm portion is visible.
A display device characterized by having a retardation plate arranged between the liquid crystal display panel and the display plate so that the crystal axis differs from the absorption axis of the polarizing member by about 45 degrees. The display device according to claim 1, wherein the throttle portion is formed into a protruding shape in cross section. Either of claims 1 and 2, characterized in that it has a first transparent resin layer that is filled between the display plate and the retardation plate and joins the display plate and the retardation plate. The display device according to item 1. Any one of claims 1 to 3, which is filled between the retardation plate and the liquid crystal display panel and has a second transparent resin layer for joining the retardation plate and the liquid crystal display panel. The display device according to item 1. The area of the surface direction of the first transparent resin layer or the second transparent resin layer according to claim 4 dependent on claim 3, characterized in that less than the area of a plane direction of the retardation plate Display device.

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