KR20110127470A - Head-up display - Google Patents

Abstract

PURPOSE: A head-up display is provided to display a clear image regardless of the intensity of external light, thereby reducing eye fatigue. CONSTITUTION: A reflective polarization part(30) reflects an image projected from a display device(10). A PVA(Poly-Vinyl Acetate) absorption type polarization part(40) is placed in the rear side of the reflective polarization part. A transmission axis of the PVA absorption type polarization part and transmission axis of the reflective polarization part are arranged to be parallel each other. A transparent base layer(20) is located in the rear side of the PVA absorption type polarization part. A rotary shaft equipped with a rotary motor is combined in the center of the transparent base layer.

Description

Head-up display {HEAD-UP DISPLAY}

The present invention relates to a head-up display capable of delivering a clear image regardless of the inflow of external light.

The head-up display (HUD) is a device that provides driving information, information on surrounding conditions, and the like within the range of the driver while driving. This applies to windshields, goggle lenses and helmet shades for aircraft, ships and vehicles.

The head-up display has conventionally been composed of a display element for emitting an image and a partial mirror (partial reflector, partial window) which makes a virtual image of the image, projects it and reflects it to the driver's eyes. However, when the partial mirror is used, all the external light behind the head-up display is introduced so that the driver cannot see the image during the day.

In addition, Korean Patent Publication No. 2005-0110614 proposes a head-up display in which a reflecting polarizer is included in a partial mirror to increase the reflectivity of a virtual image. However, the reflective polarizer can reflect approximately half of the external light (P-polarized light) but transmit the rest (S-polarized light), so if the external light is stronger than 100,000 lux, such as during the day, the driver will There was a problem that you do not see or the image is not clear.

The present invention provides a head-up display capable of delivering a clear image regardless of the inflow of external light.

1. A reflective polarizer which reflects an image emitted from a display element; An absorption type polarizer which polarizes external light introduced from the rear of the reflective polarizer to be incident on the reflective polarizer; And a control unit for adjusting an angle formed by the transmission axes of the two polarizers.

2. The head-up display of 1 above, wherein the controller is a liquid crystal panel positioned between the two polarizers.

3. The head-up display of 1 above, wherein the reflective polarizer and the absorption polarizer are linearly or rotationally moved by the controller, respectively.

4. The head-up display of 1 above, wherein the controller is operated by sensing the intensity of the external light.

5. The head-up display of 1 above, wherein the absorption type polarizer is made of a polarizer and a protective film bonded to at least one surface thereof.

6. Reflective polarizing unit for reflecting the image emitted from the display element; And a color changer unit configured to absorb external light introduced from the rear of the reflective polarizer to control an amount of light incident to the reflective polarizer.

7. The head-up display of the above 6, wherein the color fading element is to reduce the transmittance in proportion to the intensity of the external light.

The head-up display of the present invention can provide a clear image regardless of the intensity of external light introduced from the rear.

The head-up display of the present invention absorbs the external light during the day when the external light is strong to improve the contrast of the image so that the driver can observe the clear image.

The head-up display of the present invention can provide a clear image regardless of the intensity of external light, thereby reducing eye fatigue.

The head-up display of the present invention can transmit all external light at night when no image is emitted, so that it is easy to recognize the external environment.

1A-1C are exemplary head-up displays in accordance with the present invention;
2 is an exemplary head-up display with a liquid crystal panel according to the present invention;
3 is an exemplary head-up display with an electrochromic device portion according to the present invention.

The present invention provides a reflective polarizer for reflecting an image emitted from a display element; An absorption type polarizer which polarizes external light introduced from the rear of the reflective polarizer to be incident on the reflective polarizer; And a control unit for adjusting an angle formed by the transmission axes of the two polarizers, thereby providing a clear image regardless of the intensity of external light flowing from the rear of the head-up display.

Hereinafter, the present invention will be described in detail.

The head-up display of the present invention includes a reflective polarizer for reflecting an image emitted from the display element; An absorption type polarizer which polarizes external light introduced from the rear side of the reflective polarizer and enters the reflective polarizer; And a control unit for adjusting an angle formed by the transmission axes of the two polarizers.

The head-up display emits an image to the reflective polarizer in the display element and is reflected by the reflective polarizer to provide the image to the driver. At this time, the image emitted from the display element and the image reflected from the reflective polarizer have the same polarization direction.

The display device emits an image by using light generated from the light source. It may be used a light emitting, transmissive or reflective display.

The light emitting display has organic EL or inorganic EL, the transmissive display has LCD, and the reflective display has DLP and LCOS.

For example, when using a reflective display as a display device, it is preferable that the image emitted from the device and the polarized light reflected by the reflective polarizer are the same.

The display element may be built-in in the interior of the vehicle (dashboard, instrument panel, transmission gear, etc.) or may be provided externally.

The reflective polarizer provides an image to the driver by reflecting the image emitted from the display element. The reflective polarizer reflects certain polarized light and transmits the remaining polarized light.

For example, the reflective polarizer may be formed in a layer structure including a polymer that does not absorb wavelengths in the visible or infrared region. In this case, the layer structure may be a multilayer structure in which different polymer layers are alternately stacked.

Also, for example, the reflective polarizer may be a wire grid pattern in which linear metal wires are periodically arranged at nano size intervals. The metal wire may be aluminum, silver, chromium, copper, nickel, titanium, gold or two or more alloys thereof.

The absorption type polarizer polarizes the external light flowing into the rear side of the reflective polarizer to enter the reflective polarizer.

The absorption type polarizing unit transmits specific polarized light among the external light, and absorbs the remaining polarized light. For example, the absorption type polarizer may use a PVA polarizer that is an iodine absorption polarizer having excellent polarization degree and transmittance.

In addition, the absorption type polarizing part may further include a transparent substrate layer on a surface on which external light is introduced. For example, the transparent substrate layer may be a window of an aircraft, a ship, or a land vehicle.

In addition, the absorption type polarizer may be made of a polarizer and a protective film bonded to at least one side thereof.

The protective film is for protecting a weak polarizer mechanically, and may be appropriately selected and used according to transparency, mechanical strength, thermal stability, moisture shielding, and isotropy.

The protective film is, for example, polyester resin, cellulose resin, acrylic resin, styrene resin, polyolefin resin, amide resin, imide resin, polyether sulfone resin, sulfone resin, polyether sulfone resin, poly In the group consisting of thermoplastic resins such as ether ether ketone resin, polyphenylene sulfide resin, vinyl alcohol resin, vinylidene chloride resin, vinyl butyral resin, allylate resin, polyoxymethylene resin and epoxy resin The selected film can be used.

The controller adjusts the angle formed by the transmission axis of the reflective polarizer and the absorption polarizer. The angle can be changed according to the intensity of the external light within 0 to 90 degrees.

For example, when the angle formed by the polarizers is 0 ° (transmission axis is parallel to each other), the incoming external light passes through both the absorption type polarizer and the reflective type polarizer. When this case is applied at night when the inflow of external light is low, the external light is incident on the driver's eyes, so the external environment can be well recognized while driving.

For example, when the angle formed by the polarizers is 90 ° (the transmission axis is perpendicular to each other), the incoming external light is transmitted through the absorption type polarizer but not the reflective type polarizer. In this case, when the external light is introduced in a daytime, the external light is not incident on the driver's eyes, and thus, the image emitted from the display element is easily recognized.

The controller may be a liquid crystal panel positioned between the reflective polarizer and the absorption polarizer.

The liquid crystal panel changes the angles of the polarized light incident to the liquid crystal panel and the polarized light emitted by adjusting the liquid crystal alignment state according to the intensity of external light.

External light transmitted through the reflective polarizer is adjusted according to the changed angle.

The liquid crystal panel is formed by injecting liquid crystal between two transparent substrates on which electrodes are formed. The liquid crystal panel is not particularly limited, and for example, a twisted nematic mode, a vertical alignment mode, a planar switching mode, or the like may be used. It is preferable to use the planar switching mode excellent in the double light transmittance uniformity.

Since the angle between the transmission axes of the two polarizers may vary depending on the type of liquid crystal mode, it is preferable to use the liquid crystal mode.

For example, when the transmission axes of the two polarizers are perpendicular to each other and a maximum voltage is applied to the planar switching mode liquid crystal panel between the two polarizers, the polarization direction of the absorption type polarizer passes through the liquid crystal and the polarization direction is changed to 90 °. And incident on the reflective polarizer. Since the polarized light passing through the liquid crystal is the same as the transmission axis of the reflective polarizer, all of them are transmitted.

On the other hand, when 1/2 of the maximum voltage is applied, when the polarized light emitted from the absorption type polarizer passes through the liquid crystal, the polarized light is converted into elliptical polarization and incident on the reflective polarizer. The elliptical polarized light passing through the liquid crystal is partially transmitted through the reflective polarization part.

In addition, the control unit may be activated by sensing the intensity of the external light. The sensor for detecting the intensity of the external light may be connected by wire or wirelessly to control the angle of the transmission axis formed by the polarizers according to the signal of the sensor.

For example, the sensor may use one capable of recognizing a change in external light quantity.

The reflective polarizer and the absorption polarizer of the present invention may be linearly or rotationally moved by the controller, respectively.

The linear motion can be performed with a guardrail on a pair of opposing faces, for example (FIG. 1C).

The rotational movement may be performed by, for example, a rotating shaft and a rotating motor coupled to the rotating shaft and capable of rotating the reflective polarizer or the absorbing polarizer at a predetermined angle about the rotary shaft (FIG. 1B).

In particular, by controlling the angle formed by the transmission axis of the polarizer by rotating at a set angle according to the signal of the external light sensor to control the external light flowing into the reflective polarizer.

Another head-up display of the present invention includes a reflective polarizer for reflecting the image emitted from the display element; And a color changing device unit which absorbs external light flowing from the rear of the reflective polarizer to control the amount of light incident to the reflective polarizer.

The discoloration element portion has a reduced transmittance in proportion to the intensity of external light.

For example, it is possible to use an electrochromic device whose color is reversibly changed by voltage application.

As the material of the electrochromic device, a material capable of reversibly changing the optical properties of the material by electrochemical oxidation and a reduction reaction may be used. The appearance of color in the reduced state is called reduction coloration, and examples thereof include WO ₃ , MoO ₃ , TiO _3, and the like. In addition, the appearance of color in the oxidized state is called oxidation coloration, for example, V ₂ O ₃ , IrO ₂ , Nb ₂ O ₅ , NiO and the like.

The color changing device unit may operate by sensing the intensity of external light. During the day when the amount of external light is large, the transmittance of the color change device is reduced to prevent the external light from entering the driver's eyes so that the image emitted from the display device is well recognized. On the other hand, at night, the transmittance of the color change device is increased to allow the driver to enter the eye to recognize the external environment.

Hereinafter, preferred examples are provided to aid the understanding of the present invention, but the following examples are merely for exemplifying the present invention, and it will be apparent to those skilled in the art that various changes and modifications can be made within the scope and spirit of the present invention. It is natural that such variations and modifications fall within the scope of the appended claims.

Example 1

As shown in FIG. 1A, the LCD display device 10, a reflective polarizer 30 for reflecting an image emitted from the device, a PVA absorbing polarizer 40 and a PVA absorbing polarizer behind the reflective polarizer. The head-up display provided with the transparent base material layer 20 was prepared.

The transparent base layer 20 used a glass window of the vehicle, and the reflective polarizer 30 used a wire grid pattern. At this time, the transmission axis 41 of the PVA absorption type polarizing part 40 and the transmission axis 31 of the reflection type polarizing part were arranged in parallel.

The PVA absorption type polarizer 40 is coupled to the rotation axis in the center of the transparent substrate layer 20, as shown in Figure 1b, the rotation axis was provided with a rotation motor 70 for rotating the polarizer. In addition, the PVA absorption polarizer 40 is connected to the external light sensor 60 for detecting the intensity of the external light by wire. The rotation angle of the rotation motor 70 is changed according to the amount of external light measured by the detection sensor. After the preparation was completed as above, the LCD display device was operated to allow external light to flow into the reflective polarizer.

As a result, if the amount of external light detected by the detection sensor is about 100,000 lux (cloudless day at midday in the summer), the angle between the transmission axis of the PVA absorption polarizer and the transmission axis of the reflective polarizer is about 89.5 °. The absorption type polarizer was rotated. The amount of external light flowing into the reflective polarizer by the rotation was reduced to about 50 lux.

When the amount of external light flowing into the reflective polarizer is about 50 lux, the image of the LCD display device 10 is clearly seen, and a change in the external environment is recognized while driving, thereby maintaining a safe driving environment.

In addition, when the amount of external light detected by the sensing sensor was about 30 lux or less (nighttime), the PVA absorption polarizer was rotated such that the angle formed between the transmission axis of the PVA absorption polarizer and the transmission axis of the reflection polarizer was 0 °. As a result, even when the image of the LCD display device 10 is clearly seen, a change in the external environment is recognized while driving, thereby maintaining a safe driving environment.

Example 2

The configuration is the same as the second embodiment, but instead of the rotating shaft and the rotating motor as shown in Figure 2 between the PVA absorption type polarizing portion 40 and the reflective type polarizing portion 30 provided with a planar switching mode liquid crystal panel 43 head The up-display was made. When the voltage is not applied to the head-up display, the transmission axis 41 of the absorption type polarizer and the transmission axis 31 of the reflection type polarizer are disposed perpendicular to each other. In addition, the liquid crystal panel is connected to the external light sensor 60 for detecting the intensity of the external light by wire.

The voltage applied to the liquid crystal panel substrate is changed according to the amount of external light measured by the detection sensor, thereby changing the alignment state of the liquid crystal.

After the preparation was completed as above, the LCD display device was operated to allow external light to flow into the reflective polarizer.

As a result, when the amount of external light sensed by the sensor is about 100,000 lux (cloudless day at midday in the middle of summer), the polarization direction of the linearly polarized light emitted from the absorption polarizer passes through the liquid crystal and is incident on the reflective polarizer. A voltage was applied to the liquid crystal panel substrate so that the amount of light at the time was about 50 lux.

When the amount of external light flowing into the reflective polarizer is about 50 lux, the image of the LCD display device 10 is clearly seen, and a change in the external environment is recognized while driving, thereby maintaining a safe driving environment.

In addition, when the amount of external light detected by the detection sensor was about 30 lux or less (nighttime), a voltage was applied to the liquid crystal panel substrate so that the transmission axis of the polarized light passing through the liquid crystal and the reflection axis of the reflective polarizer were the same. As a result, even when the image of the LCD display device 10 is clearly seen, a change in the external environment is recognized while driving, thereby maintaining a safe driving environment.

Example 3

As shown in FIG. 3, the head-up includes a reflective polarizer 30, an electrochromic device 50, and a transparent substrate layer 20 for reflecting an image emitted from the LCD display device 10 and the LCD display device. The display was prepared.

The transparent base layer 20 uses a windshield of a vehicle, the reflective polarizer 30 has a wire grid pattern, and the electrochromic device uses a common commercial ECM mirror (ECM room mirror, Hankyung Hi-Tech) used for automobiles. It was.

The electrochromic device unit 50 is connected to the external light sensor 60 for detecting the intensity of the external light by wire.

According to the amount of external light measured by the detection sensor, the voltage applied to the electrochromic device unit 50 is changed, thereby setting the transmittance of the electrochromic device to be changed. After the preparation was completed as above, the LCD display device was operated to allow external light to flow into the reflective polarizer.

As a result, when the amount of external light sensed by the sensing sensor was about 100,000 lux (noon on a cloud at midday in summer), a voltage was applied to the electrochromic device so that the amount of external light flowing into the reflective polarizer was about 50 lux.

When the amount of external light flowing into the reflective polarizer is about 50 lux, the image of the LCD display device 10 is clearly seen, and a change in the external environment is recognized while driving, thereby maintaining a safe driving environment.

In addition, when the amount of external light sensed by the sensor was about 30 lux or less (nighttime), a voltage was applied to the electrochromic device so that the transmittance of the amount of external light flowing into the reflective polarizer was maximized. As a result, even when the image of the LCD display device 10 is clearly seen, a change in the external environment is recognized while driving, thereby maintaining a safe driving environment.

10: display element
20: transparent base material layer
30: reflection type polarizing part 31: transmission axis of reflection type polarizing part
40: absorption type polarizing part 41: transmission axis of absorption type polarizing part
43: liquid crystal panel
50: electrochromic device
60: external light sensor
70: rotating motor
80: guardrail
100: external light
200: video

Claims (7)

A reflective polarizer reflecting an image emitted from the display element;
An absorption type polarizer which polarizes external light introduced from the rear of the reflective polarizer to be incident on the reflective polarizer; And
Head-up display consisting of a control unit for adjusting the angle formed by the transmission axis of the two polarizers.
The head-up display of claim 1, wherein the controller is a liquid crystal panel positioned between the two polarizers.
The head-up display of claim 1, wherein the reflective polarizer and the absorption polarizer are respectively linearly or rotationally moved by a controller.
The head-up display of claim 1, wherein the controller is operated by sensing the intensity of the external light.
The head-up display of claim 1, wherein the absorption type polarizer comprises a polarizer and a protective film bonded to at least one surface thereof.
A reflective polarizer reflecting an image emitted from the display element; And
And a color changer unit configured to absorb external light introduced from the rear of the reflective polarizer to control an amount of light incident to the reflective polarizer.
The head-up display of claim 6, wherein the color fading element portion has a reduced transmittance in proportion to the intensity of external light.

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