JPH11281916A - Information display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an information display device which is superior in see- through property and has a high display luminance and has a combiner whose reflection factor can be adjusted from the outside. SOLUTION: This device is provided with at least a fluorescent display tube 25 which generates information to be displayed as light, a polarizing member 21 which reflects light, and a combiner 20 which reflects light from the polarizing member 21 toward an observer 1 to display it as a virtual image. A polarizing modulation member and a polarizing reflection member are arranged on the combiner 20 in order from the light incidence side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an information display device.

[0002]

2. Description of the Related Art In recent years, as a method of displaying information to a driver of a vehicle such as an automobile, a head-up display (hereinafter referred to as H
Display devices such as UD) have been used. This is because the optical information projected from an information projection member such as a liquid crystal display device is projected on a combiner incorporated in a windshield of a car, etc., and the information is superimposed on the foreground, so that the driver can almost see from the driving state. The information can be read without moving the. Further, a separate HUD mounted on a dashboard of a vehicle in which a combiner is pivotally supported by a small main body having an information display source has been used.

FIG. 8 is a conceptual diagram showing an example of a conventional HUD. Light 3 including information to be displayed, which is emitted from a light source 6 and passes through a transmissive liquid crystal display element 5 via a lens system 4 and a wavelength selection filter 11, is applied to a combiner 2 provided on a windshield 7 of a vehicle body. The reflected light is visually recognized by an observer 1 such as a driver. The lens system 4 has a function as a collimator.

Here, the windshield 7 is a laminated glass, and the combiner 2 has a laminated glass surface (inside of the vehicle).
Is formed by applying a reflective coating to the substrate. Also, by using a color information display source,
A desired multicolor image can be displayed. For example, by setting the speed display 8 to green and the warning display 9 to red, information can be more accurately transmitted to the driver.

[0005]

Since the HUD superimposes display information on the foreground, it is desirable to display a bright and easy-to-view image without obstructing the field of view. For that purpose, it is necessary to obtain high display luminance while securing the transparency of the foreground. However,
In a conventional half-mirror type combiner, there is a problem in that the transmittance and the reflectance have a trade-off relationship, and when one is increased, the other is decreased. In a windshield of an automobile, the visible light transmittance when measured vertically is 70%.
% Is required by law, so that a combiner with high reflectance cannot be adopted.

[0006] For example, in the case of a colored laminated glass, it is preferable that the thickness of the laminated glass be 0.1.
7 ≦ transmittance = (1−surface reflectance) × internal transmittance × (1−
Back reflectance), and the back reflectance = 0.04, ie, 4
%, Internal transmittance = 0.9 or 90%, the approximate surface reflectivity should be less than about 0.19 or about 19% perpendicular. When light is incident from an oblique direction, the reflectance increases as compared with the case in the vertical direction, but the reflectance is still insufficient to obtain sufficient display luminance. For this reason, a light source with a large amount of light is required to obtain high display brightness,
There were problems in terms of power consumption, heat generation and size.

FIG. 6 is a diagram showing measured values of the incident angle dependence of the visible light transmittance of a conventional HUD combiner in which a reflective glass is applied to a laminated glass made of bronze glass and clear glass. In this figure, the solid line is s-polarized light and the dotted line is p-polarized light. In this example, the visible light transmittance when measured vertically is 76%. FIG. 7 is a diagram showing a calculation result of the incident angle dependence of the surface coating reflectance of the conventional combiner, where the solid line is s-polarized light and the dotted line is p-polarized light. This figure was calculated from the data of FIG. 6 using the transmittance and the reflectance of the glass.

The reflectance at normal incidence is about 13%. In case of HUD using windshield, incident angle is 60 °
Therefore, in the case of s-polarized light, the reflectance is about 35%. Although it is larger than that at the time of normal incidence, (1-0.35)
= 0.65, that is, 65% of the light cannot be used effectively. In the case of p-polarized light, the incident angle of 60 ° is close to the Brewster's angle and there is almost no reflection.

There is a similar problem in a separately placed HUD in which the visible light transmittance has no legal regulation. Separately placed HUD
Since miniaturization is essential, there are even more severe restrictions on the size and power consumption of the light source. Moreover, since the installation angle of the combiner is nearly vertical as compared with the windshield, the incident angle of the display light is as small as 20 to 30 °.

Since the angle of incidence is small, the reflectance at the time of use is not much different from the reflectance at the time of vertical incidence, and it cannot be expected that the display luminance is increased. Therefore, a larger combiner reflectance is required. For example, when a transparent resin combiner is coated with a surface coating having a reflectance of 50%, the backside reflectance = 0.04, ie, 4%, and the internal transmittance =
Assuming 1.0 or 100%, the transmittance is about 0.
48, that is, 48%.

As a function necessary for the information display device, there is a function of adjusting display brightness in accordance with ambient brightness.
Since the reflectivity of the conventional combiner cannot be changed externally, this function is provided solely by adjusting the luminance on the information display source side. Information display is required to obtain appropriate display brightness from surrounding situations where the foreground brightness is extremely bright, such as when the weather is clear after a snowfall in midsummer or winter, or in dark surroundings such as at night or in a tunnel. It is necessary to change the luminance of the source from several hundred times to about 1000 times according to the surrounding situation. In a halogen lamp or the like, the brightness can be adjusted by controlling the current. However, in a cathode ray tube or the like often used in combination with a liquid crystal display device, it is difficult to adjust the brightness over a wide range, so that an appropriate display brightness cannot be adjusted. An object of the present invention is to provide a novel information display device that solves the above-mentioned problems of the prior art.

[0012]

SUMMARY OF THE INVENTION The present invention provides an information display source for generating information to be displayed as light, a polarizing member for transmitting or reflecting the light, and directing the light from the polarizing member to an observer. An information display device comprising at least a combiner that reflects and displays a virtual image, wherein the combiner is a device in which a polarization modulation member and a polarization reflection member are arranged in order from the light incident side. provide.

[0013] Further, a light receiving sensor for measuring ambient brightness is provided, and the light reflectance of the combiner is adjusted by adjusting the polarization modulating member according to the magnitude of the measured value. An information display device as described above is provided. Further, there is provided the information display device described above, wherein the light generated from the information display source is linearly polarized light, and a polarization direction thereof substantially coincides with a polarization axis direction of the polarization member. Further, the polarizing member has wavelength selectivity, has a polarizing function for light in a specific wavelength range, and does not have a polarizing function for light in other wavelength ranges. An information display device is provided.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the drawings. FIG. 1 is a schematic sectional view showing an example of the information display device of the present invention, and FIG. 2A is a sectional view of a combiner according to the present invention. FIG. 1 shows an example in which the present invention is applied to a separately placed HUD. Combiner 20
Is supported by the main body 22 of the HUD so as to be rotatable via the horizontal axis of the holding member 24. The bottom of the main body 22 is provided with legs 23 that can adjust the inclination and direction of the main body as necessary, and the legs 23 are held at the installation location of the HUD (for example, on the dashboard of the vehicle). .

The leg 23 is detachable from the main body 22, and is used as needed. An information display source including a fluorescent display tube 25 is provided in the main body 22. The light 3 containing information from the information display source is reflected by the reflective polarizing member, which is the polarizing member 21, and the combiner 20, and the observer 1
(For example, a driver) visually recognizes as a display image 10 such as driving information. The angle with respect to the horizontal direction of the combiner during use is theta _w, incidence of light 3 which includes information on combiner output angle is theta.

FIG. 2A is a sectional view of the combiner 20 according to the present invention. The upper side is the light incident side. The polarization modulation member 42 and the polarization reflection member 43 are laminated on the transparent substrate 40 in order from the light incident side. FIG. 2B is a cross-sectional view showing one example of the polarizing reflective member of the present invention. As the polarizing reflection member 43, a multilayer film of two or more polymer materials having different refractive indexes can be exemplified. That is, a polymer layer 1 indicated by 45 in FIG. 2B and a polymer layer 2 indicated by 46 are laminated in a plurality of layers, and at least one of the polymer layer 1 and the polymer layer 2 is birefringent. It has nature.

Here, the refractive indexes of the polymer layers 1 and 2 differ depending on the polarization direction of the linearly polarized light incident on the polarizing reflection member. That is, the refractive index differs in the polarization direction of the incident light in which the polarizing reflective member exhibits high reflection characteristics, and the refractive indices are substantially equal in the polarization direction of the incident light exhibiting the high transmission characteristics. That is, the transmittance in one direction of the two substantially orthogonal linear polarization directions is high, and the reflectance in the other direction is high. By adjusting the refractive indices of the polymer layers 1 and 2 in this manner, the polarizing reflective member can have a polarizing function.

FIG. 2C is a sectional view showing an example of the polarization modulation member according to the present invention. As the polarization modulation member 42, an electric field response type liquid crystal cell can be preferably used. For example, as shown in FIG. 2C, an electric field responsive liquid crystal 47 is sealed between two transparent insulating base materials 49 to which a transparent electrode 48 is joined to form a liquid crystal cell.

The electric field responsive liquid crystal 47 may be any liquid crystal capable of controlling the polarization state of light passing through the liquid crystal cell by applying an electric field between two transparent electrodes. The liquid crystal cell is
In a preferred embodiment, the angle between the transparent electrodes is approximately 9
TN type liquid crystal display element, ferroelectric liquid crystal element, anti-ferroelectric liquid crystal element twisted at 0 ° or an angle of 200 to 2
It is selected from STN type liquid crystal display elements twisted at 70 °.

The polarizing member 41 may be transmissive or reflective. That is, the polarizing member has a high transmittance in one direction and a low transmittance in the other direction of the two linearly polarized lights whose polarization directions are substantially orthogonal to each other, or has a high reflectance in one direction and a high reflectance in the other direction. On the other hand, it is only necessary that it be low. As the polarizing member, the above-described polarizing reflective member 43 may be used, or a transmissive polarizing member, that is, a polarizer, a polarizing film, or the like may be used. Further, it is preferable to apply an antireflection coating or a hard coating on the light incident side of the polarizing member in order to prevent the reflection of the incident light and to protect the polarizing member.

In the combiner 20 having the above configuration, when the electric field applied to the polarization modulation member is turned on and off, the reflection of light containing information and the transmission of light incident from the outside are shown in FIG. , (B) and FIG. That is, FIG. 3A is a conceptual diagram showing the state of reflection and transmission of the combiner unit in the present invention, and FIG. 3B is a diagram when the electric field applied to the liquid crystal of the combiner in the present invention is turned on and off. It is a conceptual diagram showing the state of reflectance and transmittance of the
FIG. 5 is a conceptual diagram showing the state of reflection and transmission of the combiner according to the present invention. The principle of the present invention will be described with reference to these drawings. However, in these figures, the electric field is simply expressed as electric field on and electric field off. Here, the reflectance and the transmittance indicate ideal values.

In FIG. 3A, a reflective polarizing member that reflects p-polarized light is selected as the polarizing member 41. The combiner section includes a polarization modulation member 42, a polarization reflection member 43, and a transparent substrate (not shown). TN as the polarization modulation member 42
Select a liquid crystal cell. The polarizing reflecting member 43 determines the orientation of the polarizing reflecting member with respect to the p-polarized light in the plane so as to reflect the p-polarized light. The light from the information display source 30 is randomly polarized (r) or p-polarized (p).

The p-polarized light component of the light from the information display source 30 is reflected by the reflective polarizing member 41 and guided toward the combiner. The light of the p-polarized light component that has reached the combiner passes through the polarization modulation member 42 and reaches the polarization reflection member 43. When the electric field applied to the polarization modulation member 42 is off, it is converted into s-polarized light, so that it is transmitted without being reflected by the polarizing reflection member 43. That is, the reflectivity of the combiner is 0%. On the other hand, when the electric field applied to the polarization modulation member 42 is on, the transmitted light remains p-polarized light,
The reflected light is transmitted through the polarization modulation member 42 again and observed by the observer 1 as a display image. That is, the reflectivity of the combiner is 100%.

On the other hand, light incident from the outside is randomly polarized light, and a p-polarized light component corresponding to 50% of the light is reflected by the polarizing reflection member 43. The transmitted s-polarized light component is converted into p-polarized light and transmitted when the electric field applied to the polarization modulation member 42 is off. That is, the transmittance of the combiner is 50
%. On the other hand, when the electric field applied to the polarization modulation member 42 is on, the transmitted s-polarized component is transmitted as s-polarized light. That is, the transmittance of the combiner is 50%.

FIG. 3B summarizes the above. Turning on the applied electric field of the polarization modulation member (TN liquid crystal cell),
By controlling the off and electric field magnitude, the reflectivity of the combiner can be controlled between 0% and 100%. On the other hand, for the transmitted light, the polarization direction changes, but the transmittance remains constant at 50%. That is, according to the present invention, it is possible to change the reflectance of the combiner while keeping the transmittance constant.

On the other hand, in the conventional combiner, the reflectance was fixed and could not be changed. Further, even when the fixed reflectance is determined, the reflectance and the transmittance cannot be set independently, and the value of the reflectance cannot be set while keeping the transmittance constant as in the present invention. Did not.

In the conventional combiner, only 50% reflectance was obtained when the transmittance was 50%.
100% of the reflectance is obtained, and both high reflectance and high transmittance can be achieved. Moreover, since the reflectance can be changed in the range of 0% to 100%, the brightness of the display image can be adjusted according to the foreground brightness. If a conventional luminance modulation method is used together, a wider range of luminance can be adjusted. As described above, the above-mentioned problems of the conventional information display device can be solved by the present invention.

FIG. 5 shows an example in which the polarizing member 41 is used in a transmissive arrangement. If the transmitted light has the desired polarization direction,
As the polarizing member 41, a transmitting polarizing member or a reflecting polarizing member may be used. FIG. 5 shows an example in which the p-polarized light component is transmitted. The combiner is shown in FIG.
Similarly to the above, it is composed of a polarization modulation member 42, a polarization reflection member 43, and a transparent substrate (not shown). A TN type liquid crystal cell is selected as the polarization modulation member. The polarizing reflective member 43 is p
The direction of p-polarized light in the plane of the polarizing reflective member is selected to reflect polarized light. The light from the information display source 30 is assumed to be randomly polarized light (r) or p-polarized light (p).

The p-polarized light component of the light from the information display source 30 passes through the polarizing member 41 and is guided toward the combiner.
When the light from the information display source 30 is randomly polarized light (r), the s-polarized light component is reflected or absorbed, and only the p-polarized light component is transmitted. The state of reflection of the p-polarized component light reaching the combiner and the state of transmission of light incident from the outside are the same as those in FIG. 3B described above. As described above, the same effect as that of FIG. 3A can be obtained in the arrangement of FIG.

In each of the above examples, a light receiving sensor (for example, shown at 27 in FIG. 1) is provided to measure the surrounding brightness, and the electric field applied to the liquid crystal is adjusted according to the magnitude of the measured value. For example, it is possible to automatically adjust the display brightness according to the surrounding brightness. This adjustment may be made automatically,
It may be performed manually according to the observer's preference.

In each of the above examples, the polarization direction of the polarization member 41 and the polarization direction of the polarizing reflection member 43 are the same. It is possible to obtain a combiner in which the behavior of the reflectance corresponding to the off state is reversed. That is, when the electric field applied to the liquid crystal is off, the reflectance can be 100%, and when it is on, the reflectance can be 0%. In each of the above examples, an example in which p-polarized light is guided to an observer is shown.
A configuration for guiding polarized light to the observer is obtained. As described above, according to the present invention, both high transmittance and high reflectance can be achieved.
In addition, the reflectivity can be adjusted from the outside, and the above-mentioned problem of the prior art can be solved.

As the polarizing reflective member (including the reflective polarizing member) in the present invention, a polymer multilayer film composed of two or more polymer materials having different refractive indexes can be exemplified. This configuration is described in U.S. Pat. No. 5,486,949 and International Patent Publication WO9619347.
Hereinafter, the polarizing reflective member will be described separately for each item of (1) material, (2) multilayer extrusion molding, (3) stretching, and (4) physical properties.

(1) Material In order to easily develop birefringence, it is preferable to use a polymer material. The polymer material used is transparent in the state of use. Further, those having excellent heat resistance and moisture resistance are preferable. Further, an extrudable material is preferable. Examples are methacrylate polymers (polymethyl methacrylate, polyethyl methacrylate, etc.),
Polycarbonate, styrene-based polymer (polystyrene,
Polyterephthalate (polyethylene terephthalate, polybutylene terephthalate, polycyclohexane dimethylene terephthalate, etc.), polyolefin (polyethylene, polypropylene, polymethylpentene, polyisobutylene, etc.), fluororesin (PFA, FEP, polyvinylidene fluoride, etc.) Ethylene-tetrafluoroethylene copolymer, ethylene trifluoride ethylene polymer, polyvinyl fluoride, etc.), triacetyl cellulose, polysulfone, polyether sulfone, polyalkylene naphthalate (polyethylene-2,6-naphthalate, polybutylene-2) , 6-naphthalate, etc.), 4-hydroxybenzoic acid and terephthalic acid as starting materials, main chain type polymer liquid crystal (Econol (trade name of Sumitomo Chemical Co., Ltd.)), Vectra (poly) Plastic Co., Ltd., trade name), LODRUN (Unitika Co., Ltd., trade name), etc.),
Side chain type polymer liquid crystals, and furthermore, copolymers of polyterephthalate and polyalkylene naphthalate, etc., can be mentioned. The thickness of each layer is preferably equal to or less than the wavelength of visible light. Furthermore, the thickness of each layer is 0.1 to 0.5 μm
Is preferred.

(2) Multilayer Extrusion Molding The reflective polarizing member can be manufactured by multilayer extrusion molding of two or more materials selected from these polymer materials. The technique of multilayer extrusion is disclosed in U.S. Pat.
No. 82, and U.S. Pat. No. 3,884,606.

(3) Stretching Depending on the polymer material to be used, it may be necessary to stretch the film during multilayer extrusion.
At least one of the polymer materials of the above types has a birefringent property, but in some cases, it is preferable to stretch in at least one axial direction in order to further enhance the birefringent property.

(4) Properties One or more of the two or more polymer materials exhibit birefringence by stretching or extrusion. Also,
It is preferable that the minimum two kinds of materials used have a difference in the degree of imparting birefringence by multi-layer extrusion or stretching. A material that easily imparts birefringence by multi-layer extrusion or stretching is a material having high crystallinity or liquid crystallinity, and a material that does not easily impart birefringence is an amorphous material. Generally, the refractive index in the extrusion direction or uniaxial stretching direction is larger than that in the direction perpendicular to that direction. The polarizing reflective member thus obtained has a property of reflecting polarized light in a direction having a larger refractive index difference and transmitting polarized light in a direction perpendicular thereto.

In the present invention, it is preferable that the light generated from the information display source is linearly polarized light, and the direction of the polarization substantially coincides with the direction of the polarization axis of the polarizing member for the following reasons. That is, when light generated from the information display source is transmitted or reflected by the polarizing member, light loss is small, and the light can be transmitted or reflected with high efficiency.

As the reflective polarizing member in the present invention, those having wavelength selectivity can also be preferably used. The term “wavelength selectivity” means that the light has a polarization function for light in a specific wavelength range and has no polarization function for light of other wavelengths. That is, for light in a specific wavelength range, the transmittance in one direction is high and the reflectivity in the other direction is high among the two linear polarization directions in which the polarization directions are substantially orthogonal to each other, but the reflectance in the other wavelength ranges is high. It has high transparency to light regardless of the polarization direction. Here, the light in the specific wavelength region is light such as red, green, and blue in a visible light region of 400 to 700 nm. Such a polarizing reflective member is described in, for example, Japanese Patent Application Laid-Open No. 9-506837. In order to reflect only light in the wavelength range used for display and transmit other light,
High reflectivity and higher transparency can be secured.

As the polarizing / reflecting polarizing member of the present invention, a member comprising a cholesteric liquid crystal layer and a quarter-wave plate can be used. In this case, the cholesteric liquid crystal layer and 1/4
What was superimposed on the wave plate is a polarizing reflective member.
The cholesteric liquid crystal layer has a property of transmitting, for example, right circularly polarized light components and reflecting left circularly polarized light components. Therefore, 1 /
When combined with a 4-wavelength plate, the incident linearly polarized light is 1/4
The light is converted into left-handed circularly polarized light by the wave plate and can be reflected 100%. On the other hand, for random polarization from the foreground, 5
The left circularly polarized light component corresponding to 0% is reflected, but the right circularly polarized light component is transmitted. Similar to the above-described polymer multilayer film, ideally, a reflectance of 100% and a transmittance of 50% are obtained. As such a combination of the cholesteric liquid crystal layer and the quarter-wave plate, Transmax (T
M).

It is also possible to use a reflection type hologram as the polarizing reflection member of the present invention. The hologram has different reflection / diffraction efficiency depending on the polarization direction depending on the material characteristics and the incident / emission angle. In particular, when the angle between the incident light direction and the outgoing light direction is large, the difference in diffraction efficiency depending on the polarization direction increases.

For example, when producing a hologram that diffracts light around 540 nm using a hologram material having a refractive index modulation value of 0.03 and a film thickness of 15 μm, an incident angle = outgoing angle = 0 ° (perpendicular incidence) Then, both s-polarized light and p-polarized light are about 9
Diffraction efficiency of 8%, wavelength half-width of about 14 nm and no difference due to polarization, but when the incident angle = outgoing angle = 60 °, the diffraction efficiency of s-polarized light is about 93%, the wavelength half-width of about 20 nm, and p For polarized light, the diffraction efficiency is about 62%, and the wavelength half width is about 10 nm. Since the efficiency of reflection is approximately proportional to the product of the diffraction efficiency and the half width, the reflection efficiency of s-polarized light is about three times that of p-polarized light. Thus, a reflection type hologram can also be used as a polarizing reflection member.

Next, the polarization modulation member will be described separately for each item of (A) basic structure, (B) arrangement and configuration, and (C) substrate material. (A) Basic Structure As the polarization modulation member in FIG. 2C, an electric field responsive liquid crystal can be preferably used. A liquid crystal cell having a structure in which an electric field responsive liquid crystal 47 is sealed between two transparent insulating substrates 49 with transparent electrodes 48 can be used. The insulating substrate is selected from glass, a transparent polymer, or the like, but in some cases, a polarizing reflective member may be used as it is.
The electric field responsive liquid crystal may be any liquid crystal capable of controlling the polarization state of light passing through the liquid crystal cell by applying an electric field between the transparent electrodes.

An element using an electric field responsive type liquid crystal is a liquid crystal / polymer dispersion type display element for controlling between a scattering state and a transparent state, a ferroelectric liquid crystal called smectic C ^* and an antiferroelectric liquid crystal. And a so-called twisted nematic (TN) liquid crystal element in which a nematic liquid crystal having a positive dielectric anisotropy oriented substantially parallel to each substrate exists in a twisted state. However, since the liquid crystal / polymer dispersed display element involves scattering in principle, the present invention is not necessarily suitable for window applications requiring a secure view.

The surface-stabilized ferroelectric liquid crystal found by Clark et al. Has a helix disappeared by the influence of the substrate when the chiral smectic C (Sc ^* ) liquid crystal is confined in a space having a cell thickness of about 2 μm. Is perpendicular to the surface of the substrate, and the direction is in two stable states, upper and lower. At this time, the major axis direction of the liquid crystal molecules is in a plane parallel to the substrate, and the direction is related to the direction of spontaneous polarization. Depending on the direction of spontaneous polarization, that is, upward or downward, the direction of the long axis of the molecule is in two different states in a plane parallel to the substrate, for example, rightward or leftward. Then, the direction of the spontaneous polarization is aligned with the direction of the electric field by the application of the electric field, so that the direction of the long axis of the molecule can be aligned with either the left or right direction according to the direction of the spontaneous polarization. This state can be maintained even when the electric field is turned off. When an antiferroelectric liquid crystal is used in a liquid crystal cell, the light transmission state can be selected according to the presence or absence of an electric field and its polarity.

(B) Arrangement Configuration It is desirable to appropriately select and arrange the directions of the polarization axes of the polarizing member, the polarization modulating member and the polarizing reflecting member according to the type and purpose. For example, in the case of a TN liquid crystal element, the liquid crystal is 2
Twist orientation is substantially 90 ° between the two transparent electrode substrates, and when no electric field is applied, the polarization direction of the linearly polarized light incident on the liquid crystal element is emitted after being rotated by 90 °. An arrangement is conceivable in which the polarization direction of the polarizing member and the polarization direction of the polarizing reflective member are parallel or perpendicular. The case of parallel is equivalent to the case of FIG. 3A, FIG. 3B and FIG. 5. In the case where no electric field is applied to the liquid crystal cell, the non-reflection / semi-transmissive state is obtained. Can select the total reflection / semi-transmission state. On the other hand, in the case of a right angle, a total reflection / semi-transmission state can be selected when no electric field is applied to the liquid crystal cell, and a non-reflection / semi-transmission state can be selected when an electric field is applied.

(C) Substrate Material The transparent insulating substrate 49 of the liquid crystal cell as the polarization modulating member in FIG. 2C is a glass substrate such as soda lime glass or non-alkali glass, and (1) Most of the plastic substrates exemplified in the material section can be mentioned. In the case of a plastic substrate, it can also serve as a polarizing reflective member. In the case of a plastic substrate, it may be sandwiched between glass substrates via a transparent shock absorbing film such as a polyvinyl butyral film. When the element is used outdoors, the polyvinyl butyral film preferably has an ultraviolet absorbing ability from the viewpoint of durability.

When the combiner of the present invention is used by entering light not obliquely but obliquely, the twist angle of the liquid crystal of the polarization modulating member is adjusted so that the change width of the reflectance or transmittance becomes maximum in the viewing direction. It is preferable to optimize the direction showing the maximum transmittance of the polarizing member and the polarizing reflective member.

The transparent substrate 40 of the combiner 20 according to the present invention is appropriately selected according to the use and the use situation. It is preferable that the light incident side and the reflected light emission side be transparent substrates, but this may be a material that partially transmits light. For example, in addition to a transparent glass plate, a glass plate colored with bronze, green, or the like can be used as the base material. Further, a portion through which incident light or reflected light does not pass may be opaque. As a material of the base material, besides glass, a resin substrate such as acryl, polycarbonate, polyvinyl chloride, polyolefin, or the like, or a transparent crystal may be used.

The thickness of the substrate may be a plate having a thickness of several mm, a film having a thickness of 1 mm or less, or a block having a thickness of several cm. The surface of these substrates may be provided with an antireflection coating or a hard coating, if necessary.

It is preferable that the adhesive for fixing the base material and the polarizing reflective member is one which can be adhered with necessary strength and can secure long-term reliability. As the material of the adhesive, acrylic, epoxy, urethane, vinyl acetate, rubber and the like can be widely used. Also, an adhesive or the like can be used. Examples of such forms include a photo-curing type, a thermosetting type, a curing agent mixed type, a hot melt type, and a pressure-sensitive type. Those having high transparency and low scattering property are particularly preferable in that light loss is small.

As a form of the combiner of the present invention, as shown in FIG.
3. The form in which the polarization modulation member 42 is attached is shown.
A form sandwiched between two transparent substrates is also possible. In that case, it is preferable to apply an antireflection coating or a hard coating on the light incident side as necessary.

The information display source of the information display device of the present invention has a function of emitting light to display an image. A display element comprising a so-called light receiving type display element such as a liquid crystal display element has a hot cathode tube, a cold cathode tube, A light source that emits light emitted from a light source such as a fluorescent display tube, a halogen lamp, a light emitting diode, and a semiconductor laser can be exemplified. Apart from these, a self-luminous display element that generates specific information as light by arranging the above light sources themselves in a pattern and not using a light-receiving display element may be used. Examples include a fluorescent display tube, a field emission display, a plasma display, an organic EL element, and an arrangement of light emitting diodes and semiconductor lasers.

When the information display device of the present invention performs color display, a color liquid crystal display device comprising a color filter and a transmission type liquid crystal display device can be preferably used as the liquid crystal display device. Also, fluorescent materials, luminescent materials,
A self-luminous display element in which a semiconductor material is colored may be used. In the case of a combination of a light receiving display element and a light source,
An appropriate light beam collimating member such as a lens system or a curved reflecting mirror, an appropriate light guiding member such as a light guide plate, a polarizing member, and the like may be arranged between the light receiving type display element and the light source. Optical elements, such as reflection, refraction, and diffraction, may be appropriately arranged in a light path from the information display source to the light being projected onto the combiner.
Further, a polarizing member, a non-linear optical element and the like may be arranged as necessary.

The information display device of the present invention is suitably used in a conventional HUD for automobiles. In that case, it is desirable to adjust the reflectance of the polarizing reflective member or the like so that the visible light transmittance when measured vertically is 70% or more. Further, as described above, the combiner is supported by the main body having the information display source so as to be rotatable via the horizontal axis, is mounted on the dashboard of the vehicle, and allows a driver or the like to visually recognize the driving information, It can be preferably used as a separately placed HUD.

When the information display device of the present invention is used for a vehicle, the information to be displayed is appropriately selected according to the display purpose, information such as a speedometer, a tachometer, a shift lever position of a vehicle, and various warning lamps. Information,
Examples include navigation information and information on ancillary equipment such as an air conditioner and audio equipment. Also, road information,
Information from outside the vehicle, such as parking lot availability information, can also be displayed.
For aircraft and ships, position / direction information such as latitude, longitude, altitude, direction of travel, weather information, radar obstacle information,
Various information related to vehicle operation and duties, such as information on fish finder, can be considered. The observer is mainly a driver of a vehicle such as a vehicle, but may include a passenger in the passenger seat and other passengers, and all of these persons.

In addition to the above HUD, the information display device of the present invention can be used for various purposes. For example, the present invention can also be used for an information display device in which a combiner is arranged in a dark ceramic painted portion around a windshield of an automobile. In addition, a virtual image corner marker indicating a corner of the vehicle can be exemplified.

The present invention can be applied to various display devices other than those for automobiles. For example, an information display device in which a polarizing reflective member is disposed on a window material of a shop window of a store, and an information display source in which the polarization direction is adjusted to a direction in which the reflectivity of the polarizing reflective member is high can be exemplified. In addition, the information display device of the present invention can be preferably used for explanation display of an exhibit in an art museum, an aquarium, and the like, since both the visibility of the exhibit and the visibility of the explanation information can be compatible. Further, it is useful as an information display device which is installed in a transparent partition window installed in a consultation counter of a bank, a public institution or the like, a counter or the like, and provides information necessary for business. As a similar application, a prompter can be exemplified.

[0058]

[Embodiment 1] FIG. 1 shows a separately mounted HU of this embodiment.
D. The overall configuration is shown in FIG. 3A, and the configuration of the combiner is shown in FIG. The combiner 20 is composed of an acrylic resin base material, a polarizing reflective member 43, a polarization modulating member
With a transparent adhesive. A 3M D-BEF plate was used as the polarizing member 21 and the polarizing reflective member 43. As a polarization modulating member, after applying polyimide on two substrates with ITO film and heating, the rubbing direction was crossed by 90 °, and the gap 6 was rubbed.
A liquid crystal cell prepared by injecting a liquid crystal ZLI1565 (manufactured by Merck) into a cell of μm was used.

The fluorescent display tube 25 is used as the information display source in FIG.
Was used. Since the polarization direction of the light emitted from the information display source is random, only about 50% of the light that is reflected by the polarization member 21 and reaches the combiner has the same polarization direction. The angle of the combiner with respect to the horizontal direction is 75 °, and the incident angle of light is 20 ° measured from the normal direction (dotted line).
It is.

FIG. 4 shows measured values of the wavelength dependence of the transmittance of the combiner with respect to the linearly polarized light incident at 20 °. The solid line shows the state where the applied electric field is on, and the dotted line shows the state where the applied electric field is off. Since it is difficult to measure the absolute value of the reflectance, the conversion is made from the measurement of the transmittance. The combiner showed a transmittance of 87.9% when the applied electric field was off, that is, when 0 V (volt) was applied, and showed a transmittance of 5.0% when 5 V was applied. If the reflection and absorption losses are ignored, the reflectivity of the combiner is 1
It can be modulated from 2.1% to 95.0%. (5.0 + 87.9) / 2 = 46 for random polarization.
The transmittance becomes 5%. Compared with the conventional example using the above-mentioned reflective coating, the same visible light transmittance was obtained, but at the same time the reflectance was almost doubled at the maximum.

Further, by controlling the voltage applied to the liquid crystal cell in accordance with the signal from the light receiving element 27, the reflectance can be made variable according to the surrounding brightness, and an information display with good visibility can be obtained. I was able to. Also, an information display device capable of externally modulating the reflectance was realized.

[Embodiment 2] In this embodiment, the fluorescent display tube of Embodiment 1 was replaced with a combination of a transmission type color liquid crystal display device and a backlight of a cold cathode tube. The direction of polarized light from the liquid crystal display element was made to coincide with the direction in which the reflectance of the polarizing member 21 was maximum. As in the first embodiment, the entire configuration is as shown in FIG. 3A, and the configuration of the combiner is as shown in FIG. Since the direction of the polarized light from the liquid crystal display element is made to coincide with the direction in which the reflectance of the polarizing member 21 is maximum, almost 100% of the light from the liquid crystal display element is reflected and guided to the combiner.

The reflectivity and transmittance of the combiner are exactly the same as those of the first embodiment, and an information display device which achieves both high transmittance and high reflectivity and modulates the reflectivity from the outside can be realized.

[0064]

As described above, according to the present invention, an information display device having excellent transparency and high display luminance can be obtained. Further, an information display device whose reflectance can be adjusted from the outside can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of an information display device of the present invention.

FIG. 2A is a sectional view of a combiner according to the present invention;
(B) Sectional drawing which shows an example of the polarizing reflective member in this invention, (c) Sectional view which shows an example of the polarization modulation member in this invention.

FIG. 3A is a conceptual diagram showing a state of reflection and transmission of a combiner according to the present invention, and FIG. 3B is a diagram showing the reflectance and transmittance of the combiner according to the present invention when an electric field applied to a liquid crystal is turned on and off. The conceptual diagram which shows a situation.

FIG. 4 is a diagram showing the wavelength dependence of the transmittance of the combiner according to the present invention when the electric field applied to the liquid crystal is turned on (solid line) and off (dotted line).

FIG. 5 is a conceptual diagram showing a state of reflection and transmission of a combiner according to the present invention.

FIG. 6 is a diagram showing an example of the incident angle dependence of the visible light transmittance of a conventional combiner. The solid line indicates s-polarized light and the dotted line indicates p-polarized light.

FIG. 7 is a diagram showing an example of the incident angle dependence of the surface coating reflectance of a conventional combiner. Solid line is s-polarized light, dotted line is p
Indicates polarized light.

FIG. 8 is a conceptual diagram showing an example of a conventional HUD.

[Explanation of symbols]

 1: observer 3, 3 ': light containing information 10: display image 20: combiner 21: polarizing member 22: main body 25: fluorescent display tube 27: light receiving sensor 30: information display source 40: transparent substrate 41: polarized light Member 42: Polarization modulating member 43: Polarizing reflective member 45: Polymer layer 1 46: Polymer layer 2 47: Electric field responsive liquid crystal 48: Transparent electrode 49: Transparent insulating substrate

Claims (4)

[Claims] An information display source that generates information to be displayed as light, a polarizing member that transmits or reflects the light, and a combiner that reflects the light from the polarizing member toward an observer and displays it as a virtual image. The information display device according to claim 1, wherein the combiner includes a polarization modulation member and a polarization reflection member arranged in this order from the light incident side. 2. A light receiving sensor for measuring ambient brightness, wherein the light reflectance of the combiner is adjusted by adjusting the polarization modulation member in accordance with the magnitude of the measured value. The information display device according to claim 1, wherein: 3. The information display device according to claim 1, wherein the light generated from the information display source is linearly polarized light, and the polarization direction thereof substantially coincides with the polarization axis direction of the polarization member. . 4. The polarizing member has wavelength selectivity, has a polarizing function for light in a specific wavelength range, and does not have a polarizing function for light in other wavelength ranges. The information display device according to claim 1, 2 or 3, wherein