JPH11271665A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple display device capable of preventing double images by using a liquid crystal display device having the normal polarization axis of 45 deg.. SOLUTION: Display information from the liquid crystal display device 6 having the polarization axis of 45 deg. to a vertical axis on the display screen is projected on the surface of transparent planar bodies 1 and 1' by the incident angle of the Brewster angle, reflected and displayed on the eye point 8 on the side of the display device 6 by the transparent planar bodies 1 and 1' or a translucent reflection film 3 provided on the transparent planar bodies 1 and 1'. In this case, an azimuth rotator 7 for performing 45 deg. optical rotation is installed on the front surface of the liquid crystal display device 6 or the azimuth rotator for performing the 45 deg. optical rotation and attaining P wave is installed to the transparent planar bodies 1 and 1'.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a liquid crystal display as a display, projects display information from the display onto a windshield of a vehicle or the like, or a combiner provided on the windshield, so that the display information can be viewed from within a front view. The present invention relates to a display device for a vehicle, a head-up display for a ship (hereinafter, abbreviated as HUD), a building, or the like in which a foreground in the vicinity thereof is superimposed and visually recognized by a driver or the like.

[0002]

2. Description of the Related Art Conventionally, as a HUD, a film or a film having a function of a half mirror has been formed or bonded on the surface of a single glass plate or the inside of a laminated glass. However, reflection on the front or back surface of the glass sheet is unavoidable, and there is a drawback that the image is double-viewed. In order to prevent this double image, a λ / 2 plate (optical rotation) Child layer)
(Japanese Unexamined Patent Publication No. 2-141720) has been proposed, and the present applicant has also proposed a method in which a transparent film having birefringence is adhered to a transparent plate-shaped body (Japanese Unexamined Patent Publication No. 2-294615). An optical rotator made of a liquid crystal polymer adhered (Japanese Patent Application Laid-Open No. 6-40271), an optical rotator and a translucent reflective film,
Combination of antireflection films (Japanese Patent Application No. Hei 7-98878)
No.).

In this case, as a display, a liquid crystal display is known together with a fluorescent display tube and the like.

[0004]

However, a liquid crystal display, which is widely used as a normal display, usually has a display screen except for some small liquid crystal televisions in order to maintain the symmetrical viewing angle. The polarization axis is set to be substantially diagonal (horizontal and oblique in the vertical direction) with respect to the vertical axis.

For this reason, it is impossible to prevent a double image from occurring by using a conventional liquid crystal display and using a conventional optical rotator that rotates the 90 ° polarization direction. It is necessary to use a small-sized liquid crystal display having a parallel or perpendicular polarization axis, or to specially manufacture a display whose polarization axis is adjusted for exclusive use.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to provide a simple display device which prevents a double image by using a liquid crystal display having a normal 45-degree polarization axis. Aim.

[0007]

In order to solve such a problem, a display device according to the present invention is provided on a transparent plate-like body provided with a part of a rotator that makes a 90 ° rotation. Display information from a liquid crystal display having a polarization axis of 45 ° with respect to the vertical axis is expressed as S-polarized light (hereinafter referred to as S-wave) whose electric field direction is perpendicular to the surface of the transparent plate, or a transparent plate. Irradiation with P-polarized light (hereinafter referred to as P-wave) whose electric field direction is parallel to the body surface at a Brewster angle, and a transparent plate or a semi-transparent reflective film provided on the transparent plate is used to illuminate the display side. In a display device that reflects light at an eye point and displays an image, a rotator that rotates 45 ° is installed on the front of the liquid crystal display, or a liquid crystal display having a polarization axis of 45 ° with respect to the vertical axis on the display screen is used. Information is reflected on the transparent plate In a display device that irradiates at a star angle and reflects the light to the eye point on the liquid crystal display side by a transparent plate or a semi-transparent reflective film provided on the transparent plate for display, the direction of the electric field is changed by 45 ° rotation. An optical rotator having P-polarized light parallel to the transparent plate is provided on the transparent plate.

[0008] The present invention is based on the assumption that 4
By installing an optical rotator that rotates 45 ° on the front surface of a liquid crystal display having a polarization axis of 5 °, the polarized light having the same polarization plane as that of the original display is polarized by a polarizing plate having a polarization axis of 90 °. As a result, a double image can be prevented. Alternatively, by installing an optical rotator that rotates the light by 45 ° and turns it into a P wave on the transparent plate, the P wave is emitted at the Brewster angle from the back of the transparent plate, so there is no reflection on the back and there is no double image. Can be prevented.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As a transparent plate, inorganic glass such as plate glass or organic glass such as a transparent resin plate can be used. Not only a single plate but also two transparent plates can be used as an intermediate film. It can be applied to a structure with a laminated structure such as a glass plate and a transparent resin plate, etc., and is also used as a combiner in a windshield for automobiles (laminated glass) or as a combiner in a single plate glass. As a separate combiner, not only can they be applied to a head-up display, but they can also be provided on architectural glass, partitions, and the like to perform various displays.

When applied to windshields for vehicles,
It is preferable to provide an optical rotator layer on the mating surface side of the vehicle exterior glass sheet because the impact resistance and penetration resistance are improved, and when provided on the mating surface side of the vehicle interior glass sheet, sunlight passes through the polyvinyl butyral which is the interlayer. Since the light is irradiated to the optical rotator, the ultraviolet light is absorbed to some extent, and the durability is improved.

As for the optical rotator, a twisted nematic alignment in a liquid crystal state, and a liquid crystal polymer which is in a glassy state below a liquid crystal transition point is used so that a double image cannot be seen over the entire visible region. However, for a specific wavelength, a transparent film having birefringence, an optical rotator layer such as a λ / 2 plate, or the like can also be used.

Such an optical rotator is obtained by applying a liquid crystal polymer onto a transparent substrate such as a transparent plastic film such as polyethylene terephthalate (PET), applying a shearing force, an electric field or a magnetic field, and then heat-treating and cooling the liquid crystal. It can be obtained by fixing the orientation.

An alignment film such as a rubbing polyimide film, a rubbing polyvinyl alcohol film, or a film obtained by obliquely depositing silicon oxide is formed on a transparent substrate, and a liquid crystal polymer is applied thereon. Can be adopted.

Further, after the liquid crystal alignment is fixed by the above-mentioned means, the liquid crystal polymer itself can be used as a rotator without a transparent substrate. Here, the thickness of the optical rotator is 0.5 to 20 μm, preferably 1 to 15 μm.

The angle of rotation can be adjusted by controlling the content of the optically active unit component in the liquid crystal polymer, the thickness of the liquid crystal polymer, and the conditions during heat treatment for developing liquid crystallinity.

As the liquid crystal polymer, those which are twisted nematic in the liquid crystal state and become glassy below the liquid crystal transition point can be used. Main-chain type liquid crystals such as optically active polyester, polyamide, polycarbonate and polyesterimide can be used. Polymers or optically active polyacrylates, polymethacrylates, polymalonates,
A side chain type liquid crystal polymer such as polysiloxane can be used.

Also, a polymer composition or the like obtained by adding other low-molecular or high-molecular optically active compounds to these main-chain or side-chain polymers which are not optically active can be used.

Specifically, various polymers represented by Chemical Formulas 1 to 7 can be exemplified. All of these polymers have a glass transition point in the range of 0 ° C to 150 ° C,
It shows a twisted nematic orientation at a temperature higher than the glass transition point, and becomes a glass at a temperature lower than the glass transition point.

[0019]

Embedded image

(M / n = usually 99.n)
9 / 0.1-70 / 30, preferably 99.8 / 0.2
９０90/10, more preferably 99.7 / 0.3９9
5/5). (* In the formula indicates an optically active carbon. The same applies to the following chemical formulas.)

[0021]

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(M / n = normally 0.1)
/99.9 to 10/90, preferably 0.3 / 99.7
５5/95).

[0023]

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A polymer represented by the formula (k = 1 + m + n, k
/ N = normally 99.9 / 0.1 to 90/10, preferably 99.7 / 0.3 to 95/5, l / m = 5/95 to 95
/ 5).

[0025]

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A polymer represented by the formula (k = 1 + m + n, k
/ N = normally 99.9 / 0.1 to 90/10, preferably 99.7 / 0.3 to 95/5, l / m = 5/95 to 95
/ 5).

[0027]

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The polymer mixture represented by the formula ((A) /
(B) = usually 99.9 / 0.1 to 80/20 (weight ratio), preferably 99.8 / 0.2 to 90/10, more preferably 99.7 / 0.3 to 95/5, k = 1 +
m, l / m = 75/25 to 25/75, p = q + r, q
/ R = 80/20 to 20/80).

[0029]

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The polymer mixture ((A) /
(B) = usually 99.9 / 0.1 to 70/30 (weight ratio), preferably 99.8 / 0.2 to 80/20, more preferably 99.7 / 0.3 to 90/10, m = k +
1, k / l = 80/20 to 20/80).

[0031]

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The polymer mixture ((A) /
(B) = usually 99.9 / 0.1 to 70/30 (weight ratio), preferably 99.8 / 0.2 to 80/20, more preferably 99.7 / 0.3 to 90/10, K = 1 +
m, l / m = 25/75 to 75/25, p = q + r, q
/ R = 20 / 80-80 / 20). The molecular weight of these polymers can be determined in various solvents such as tetrahydrofuran, acetone, phenol / tetrachloroethane (60/40)
The logarithmic viscosity measured at 30 ° C in a mixed solvent is 0.0
The range is preferably from 5 to 3.0 (dl / g), more preferably from 0.07 to 2.0 (dl / g).

When the logarithmic viscosity is smaller than 0.05, the strength of the obtained polymer liquid crystal becomes low, which is not preferable. If it is larger than 3.0, the viscosity at the time of liquid crystal formation is too high,
It is not preferable because there is a possibility that the time required for the orientation is lowered and the orientation is required.

When display information is radiated from the liquid crystal display to the transparent plate at a Brewster angle, an S wave whose electric field direction is perpendicular to the incident surface of the transparent plate or a P wave parallel to the incident surface is used. However, it is preferable to use the S-wave because it can be reflected on the outermost surface and the amount of reflection to the eye point is larger than that in the case of the P-wave.

Although the polarization axis of the liquid crystal display in the present invention is polarized at 45 ° with respect to the vertical axis of the display screen, it may be 45 ° to the right or 45 ° to the left. When the light is polarized 45 ° to the right, a rotator that rotates 45 ° to the left becomes S-polarized light, and when a rotator that rotates 45 ° to the right is used, it becomes P-polarized. The body can be irradiated.

When the light is rotated left by 45 °, a rotator that rotates 45 ° to the right is used to obtain S-polarized light, and when a rotator that rotates 45 ° to the left is used, P is used.
The transparent plate can be irradiated as polarized light.

The reflective surface of the display information may be reflected on the front or back surface of a transparent plate such as a plate glass. However, when a semi-transparent reflective film is provided and reflected on this surface, the surface of the transparent plate or the reflective surface may be reflected. This is preferable because the amount of light reflected on the eye point is larger than when the light is reflected on the back surface.

In this case, it is necessary to provide on the outermost surface on the display side when the light is incident on the S-wave, and on the rearmost surface of the transparent plate opposite to the display side for the P-wave. There is. As the translucent reflection film, a metal thin film of Al, Au, Ag, Cu or the like can be suitably used.

[0039]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 and FIG. 2 are schematic views of a main part in which the laminated glass in Example 1 and Example 2 of the present invention is used as a windshield for an automobile and applied as a HUD.

Example 1 A case where a laminated glass is irradiated with S-waves as display information and twisted nematically aligned in a liquid crystal state as an optical rotator, and an optical rotator made of a liquid crystal polymer which is in a glassy state below a liquid crystal transition point is used. Will be exemplified.

As such an optical rotator, a liquid crystal polymer is coated on a transparent substrate such as a transparent plastic film such as polyethylene terephthalate (PET), and then subjected to a shearing force, followed by heat treatment and cooling to fix the liquid crystal alignment. As the polymer, a twisted nematic alignment in a liquid crystal state and a glassy state below the liquid crystal transition point can be obtained. For example, a liquid crystal polymer represented by the following formula (Formula 8) (shown by the above-mentioned chemical formula 3) is used. I do.

[0042]

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By controlling the content of the optically active unit component in the liquid crystal polymer, the thickness of the liquid crystal polymer, and the conditions at the time of heat treatment for developing liquid crystallinity, an optical rotator rotating at 90 ° and an optical rotator rotating at 45 ° can be obtained. Prepare each.

After the substrate film of the optical rotator film 2 having a 90 ° optical rotation obtained in this manner is peeled off, it is adhered to the concave side of the outdoor glass sheet 1 via a double-sided adhesive tape (not shown).

A metal thin film of Al, Au, Ag, or Cu is formed as a translucent reflective film 3 on a part of the concave surface side of the indoor side sheet glass 1 'by vapor deposition or the like. Thereafter, the sheet glass 1 as the transparent sheet body on the outdoor side and the sheet glass 1 ′ as the transparent sheet body on the indoor side are temporarily bonded by an intermediate film 4 such as polyvinyl butyral, and are subjected to a normal autoclave treatment to be combined for a vehicle. Glass 5 is obtained.

As shown in FIG. 1, the laminated glass 5 is mounted as a windshield for an automobile, and the Brewster angle (θ
Liquid crystal display 6 having a polarization axis of, for example, 45 ° in the right direction with respect to the vertical axis on the display screen and 45 degrees in the left direction, for example, attached to the front of the display so that the display information is incident at 56 °. A {7} optical rotator (rotating in this example so as to make an S wave by 45 [deg.] Rotation) is arranged.

In such a display device, first, when display information polarized, for example, 45 ° to the right is output from the liquid crystal display 6 with respect to the vertical axis on the display screen, the liquid crystal is rotated to the left by 45 °. The light is rotated by the optical rotator into an S wave, reaches the indoor side glass plate 1 ′, and a part of the light is reflected by the translucent reflective film 3 on this surface, reaches the eye point 8 on the liquid crystal display side, and the display information is displayed. Clearly visible.

On the other hand, the light (S-wave) incident on the laminated glass without being reflected by the translucent reflection film is rotated by the 90 ° optical rotator 2 into a P-wave and reaches the rear surface, but at a Brewster angle. Since the light is emitted, it is reflected on the back surface and is not reflected on the eye point side, and the entire amount is emitted.

In this case, even if there is no translucent reflective film, the light is reflected on the outermost surface of the indoor side glass sheet, so that the amount of reflection on the eye point side is reduced, although not always necessary. Example 2 A case in which a P-wave is irradiated as a display information on a laminated glass will be exemplified.

After the substrate film of the optical rotator film 2 having a 90 ° optical rotation obtained by the same method as in Example 1 is peeled off, it is adhered to the concave side of the outdoor glass sheet 1 via a double-sided adhesive tape (not shown).

On the other hand, a metal thin film of Al, Au, Ag, Cu is formed as a translucent reflective film 3 on a part of the surface of the outdoor sheet glass 1 on the convex side by vapor deposition or the like. Thereafter, the sheet glass 1 as the transparent sheet body on the outdoor side and the sheet glass 1 ′ as the transparent sheet body on the indoor side are temporarily bonded by an intermediate film 4 such as polyvinyl butyral, and are subjected to a normal autoclave treatment to be combined for a vehicle. Glass 5 is obtained.

As shown in FIG. 2, the laminated glass 5 is mounted as a windshield for an automobile, and the Brewster angle (θ
Liquid crystal display 6 having a polarization axis of, for example, 45 ° to the left with respect to the vertical axis on the display screen so that display information is incident at 56 °), and 45 ° to the left, for example, attached to the front of the display. A {rotatable optical rotator (in this example, 45 [deg.] Optical rotation to form a P-wave) 7 is arranged.

In such a display device, first, when display information polarized at 45 ° with respect to the vertical axis on the display screen is output from the liquid crystal display 6, the 45 ° optical rotator 7 rotates the P-wave. As a result, the P wave is incident at the Brewster's angle, but there is no reflection on the surface of the indoor side glass sheet, and the light (P wave) totally incident on the laminated glass does not reach the indoor glass sheet 1 '. The light is turned into an S wave by the 90 ° optical rotator 2 and reaches the back surface, and a part of the light is emitted from the back surface. Other light (S wave) is reflected by the reflection film 3 and passes through the 90 ° optical rotator 2 again. , The light is rotated by the P wave and reaches the surface of the indoor side glass sheet, and the P wave is emitted at the Brewster's angle, so there is no reflection on this surface, and the entire amount is emitted and the eye point 8 on the liquid crystal display side is obtained. , And the display information is visually recognized.

Even in this case, even if there is no translucent reflection film, the light is reflected on the rearmost surface of the outdoor glass sheet, so that the reflection amount to the eye point side is reduced, although not always necessary.

Embodiment 3 An example will be described in which a rotator that is turned into a P-wave by rotating it by 45 ° is disposed on the transparent plate. By controlling the content of the optically active unit component in the liquid crystal polymer, the thickness of the liquid crystal polymer, the conditions at the time of heat treatment for developing liquid crystallinity, etc., optical rotators that make 45-degree optical rotation and turn into P waves are produced. After peeling off the substrate film of the optical rotator film 7 having a 45-degree optical rotation obtained in this way, the outdoor side sheet glass 1 was removed.
Is bonded to the concave side of the substrate through a double-sided adhesive tape (not shown).

On one indoor side plate glass 1 ′, a metal thin film of Al, Au, Ag, or Cu is formed as a translucent reflective film 3 on a part of the concave surface by vapor deposition or the like. Thereafter, the sheet glass 1 as the transparent sheet body on the outdoor side and the sheet glass 1 ′ as the transparent sheet body on the indoor side are temporarily bonded by an intermediate film 4 such as polyvinyl butyral, and are subjected to a normal autoclave treatment to be combined for a vehicle. Glass 5 is obtained. As shown in FIG. 3, the laminated glass 5 is mounted as a windshield for an automobile, and a display screen is provided so that display information is incident on the windshield at a Brewster angle (θ = 56 °) of the windshield. A liquid crystal display 6 having, for example, a polarization axis of 45 ° to the right with respect to the upper vertical axis is arranged.

In such a display device, first, when display information which is polarized, for example, rightward by 45 ° with respect to the vertical axis on the display screen from the liquid crystal display device 6, is output, the indoor side sheet glass is kept in that state. When the light reaches 1 ', a part of the light is reflected by the translucent reflective film 3 on the surface, reaches the eye point 8 on the liquid crystal display side, and the display information is clearly recognized. On the other hand, light incident on the laminated glass without being reflected by the translucent reflection film is almost rotated to a P wave by the 45 ° optical rotator 7 and reaches the rear surface, but is emitted at a Brewster angle, and is reflected on the rear surface. Is hardly reflected to the eye point side,
Almost the entire amount is emitted. In this case, even if there is no translucent reflective film, the light is reflected on the outermost surface of the indoor side glass sheet, so that the amount of reflection to the eye point side is reduced, although not necessarily required.

[0058]

The display device of the present invention uses a liquid crystal display device having a polarization axis of 45.degree. On the screen, and can prevent double images from occurring by a simple device.

[Brief description of the drawings]

FIG. 1 is a schematic view of a main part in which the laminated glass in Example 1 is used as a windshield for an automobile and applied as a HUD.

FIG. 2 is a schematic diagram of a main part in which the laminated glass in Example 2 is used as a front glass for an automobile and applied as a HUD.

FIG. 3 is a schematic view of a main part in which the laminated glass in Example 3 is used as a windshield for an automobile and applied as a HUD.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1 'Transparent plate-like body 2 90 degree optical rotator 3 Translucent reflective film 4 Intermediate film 5 Laminated glass 6 Liquid crystal display 7 45 degree optical rotator 8 Eye point

Claims (3)

[Claims] 1. An optical rotator that rotates 90 ° to provide display information from a liquid crystal display having a polarization axis of 45 ° to a vertical axis on a display screen in a transmission part of incident light of the liquid crystal display. The transparent plate thus obtained is irradiated with S-polarized light whose electric field direction is perpendicular to the surface of the transparent plate at an incident angle of Brewster's angle, and the transparent plate or the half provided on the transparent plate is irradiated. A display device for reflecting an image at an eye point on the liquid crystal display side by a transparent reflection film to display an image, wherein a rotator that rotates by 45 ° is disposed in front of a display screen of the liquid crystal display device. 2. An optical rotator having a 90-degree optical rotation is provided on a transparent plate member provided at a part thereof, with respect to a vertical axis on the display screen.
Display information from a liquid crystal display having a polarization axis of 5 ° is radiated with P-polarized light whose electric field direction is parallel to the surface of the transparent plate-like body at an incident angle of Brewster's angle. In a display device that transmits light and reflects it at an eye point on the display side by a transparent plate or a translucent reflective film provided on the transparent plate to display the image, a rotator that rotates 45 ° is displayed on the display screen of the liquid crystal display. A display device characterized by being installed on the front. 3. A transparent plate-like body which irradiates information from a liquid crystal display having a polarization axis of 45 ° with respect to a vertical axis on a display screen at a Brewster angle at an incident angle with respect to a transparent plate-like body surface. Alternatively, in a display device in which an image is reflected at an eye point on the liquid crystal display side by a semi-transparent reflective film provided on a transparent plate and a display is performed, the light is rotated by 45 ° and the electric field direction is parallel to the transparent plate. Display device characterized in that an optical rotator as polarized light is disposed on the transparent plate.