KR20210145655A - System of virtual image projectiion on screen with effect of eliminating influence of solar radiation - Google Patents

Abstract

Provided is a system for projecting a virtual image on a screen with an effect of eliminating the influence of solar radiation, which polarizes solar radiation in an optical path along which solar radiation is delivered to a display through a screen, eliminates and filters out ultraviolet and infrared components, and processes only radiation of an operating range of the display to the display.

Description

SYSTEM OF VIRTUAL IMAGE PROJECTIION ON SCREEN WITH EFFECT OF ELIMINATING INFLUENCE OF SOLAR RADIATION

The following embodiments relate to projecting a virtual image on an augmented reality device, in particular an augmented reality screen.

Head-up display (HUD) systems for projecting images onto transparent or translucent screens are becoming increasingly popular. Such systems are used to project images on virtual reality helmets or car windshields, etc. Windshield projection systems have been used on military aircraft and with the help of these systems the pilot can read flight data from the aircraft windshield rather than the instrument cluster. However, there is a problem in that the head-up display is overheated by solar radiation through the windshield in an environment in which the projection display image is projected on the windshield. A projection display system for image projection consists of a display, projection optics and a windshield, the solar radiation passing through the windshield concentrates a strong amount of light on the display, which causes the display to start overheating, resulting in distorted color transmission from the display. This can happen and can ultimately lead to damage to the display.

Various solutions have been proposed to solve the problem of overheating of the display due to solar radiation. For example, a fan system may be used but such a system may be bulky and noisy. Water cooling solutions are also possible, but these systems are complex and expensive.

In the prior art, when the amount of solar radiation is greatly increased, a method of lowering the temperature of the display by lowering the brightness of the backlight illumination is used. In this case, there is a problem that limits the use of the system.

Therefore, there is a need for a technique for preventing overheating of a display by solar radiation and distorted color transmission in a display due to overheating and damage to the display by removing harmful solar radiation.

An image projection system according to an embodiment of the present disclosure includes a screen; polarizing filters; selective dichroic filter; a first mirror; a second mirror; and a display, wherein the polarizing filter, the optional dichroic filter, the first mirror, the second mirror are positioned between the screen and the display, and the polarizing filter is configured to reduce solar radiation passing through the screen. wherein the optional dichroic filter is positioned behind the polarizing filter and transmits radiation in the operating range of the display in radiation polarized through the polarizing filter, the ultraviolet component of the radiation and/or the infrared component of the radiation; the first mirror reflects radiation that has passed through the selective dichroic filter to the second mirror, and the second mirror reflects the infrared component of the radiation reflected from the first mirror and It transmits or absorbs the ultraviolet component of radiation and directs radiation having a remaining wavelength that is not transmitted or absorbed in the radiation reflected from the first mirror to the display.

In this case, the image projection system may further include a radiation source located behind the display.

In this case, the polarization filter includes a linear s-polarizer with a quarter-wave plate, a linear p-polarizer with a quarter-wave plate, and a left polarizer. It may be one of a circular polarizer with

An image projection system according to another embodiment of the present disclosure includes a screen; polarizing filter; optional dichroic filter; filter; a first mirror; a second mirror; and a display, wherein the polarizing filter, the optional dichroic filter, the first mirror, and the second mirror are positioned between the screen and the display, the polarizing filter polarizing solar radiation passing through the screen; The optional dichroic filter is located behind the polarizing filter and transmits radiation in the operating range of the display, the ultraviolet component of the radiation and/or the infrared component of the radiation among the radiation polarized through the polarizing filter, and reflects all other wavelengths of radiation. and the filter absorbs the ultraviolet component and the infrared component of radiation, transmits all other wavelengths of radiation that are not absorbed, and the first mirror captures the radiation that has passed through the polarizing filter, the selective dichroic filter and the filter. Reflecting to the second mirror, the second mirror directs the radiation reflected from the first mirror to the display.

In this case, the image projection system may further include a radiation source located behind the display.

In this case, the filter may be located in front of the polarizing filter or located after the selective dichroic filter.

In this case, the polarization filter includes a linear s-polarizer with a quarter wave plate, a linear p-polarizer with a quarter wave plate, a circular polarizer with a left polarization, a circular polarizer with a right polarization, a linear s-polarizer, and a linear p - It can be one of the polarizers.

An image projection system according to another embodiment of the present disclosure includes a screen; a first mirror; a second mirror; polarizing filter; optional dichroic filter; and a display, wherein the first mirror, the second mirror, the polarization filter, and the optional dichroic filter are positioned between the screen and the display, and the first mirror directs the solar radiation passing through the screen to the second mirror. reflected by two mirrors, wherein the second mirror transmits or absorbs the ultraviolet component of the solar radiation and/or the infrared component of the solar radiation, and transmits radiation having a remaining wavelength that is not transmitted or absorbed in the solar radiation through the polarizing filter wherein the polarizing filter polarizes the radiation reflected from the second mirror, and the optional dichroic filter is located behind the polarizing filter and directs radiation in the operating range of the display in radiation polarized through the polarizing filter. It transmits and directs to the display, and reflects the remaining wavelengths of radiation not transmitted by the selective dichroic filter.

In this case, the image projection system may further include a radiation source located behind the display.

In this case, the polarization filter includes a linear s-polarizer with a quarter wave plate, a linear p-polarizer with a quarter wave plate, a circular polarizer with a left polarization, a circular polarizer with a right polarization, a linear s-polarizer, and a linear p - It can be one of the polarizers.

An image projection system according to another embodiment of the present disclosure includes a screen; polarizing filter; a first mirror; a second mirror; and a display, wherein the polarizing filter, the first mirror, and the second mirror are positioned between the screen and the display, the polarizing filter polarizing solar radiation, the first mirror polarizing through the polarizing filter all other non-reflected radiation of the polarized radiation through the polarizing filter that reflects the radiation of the display operating range in the polarized radiation to the second mirror, the ultraviolet component of the polarized radiation and/or the infrared component of the polarized radiation absorbs radiation of a wavelength, wherein the second mirror transmits or absorbs the ultraviolet component of the radiation reflected from the first mirror and/or the infrared component of the radiation reflected from the first mirror, and the second mirror transmits or absorbs the infrared component of the radiation reflected from the first mirror; All other wavelengths in the radiation that are not transmitted or absorbed are reflected towards the display.

In this case, the first mirror may be a selective dichroic mirror.

In this case, the image projection system may further include a radiation source located behind the display.

In this case, the polarization filter includes a linear s-polarizer with a quarter wave plate, a linear p-polarizer with a quarter wave plate, a circular polarizer with a left polarization, a circular polarizer with a right polarization, a linear s-polarizer, and a linear p - It can be one of the polarizers.

An image projection system according to another embodiment of the present disclosure includes a screen; polarizing filter; a first mirror; a second mirror; and a display, wherein the polarizing filter, the first mirror, and the second mirror are positioned between the screen and the display, the polarizing filter polarizing solar radiation, the first mirror polarizing through the polarizing filter The second mirror transmits or absorbs the ultraviolet component of the polarized radiation and/or the infrared component of the radiation polarized through the polarizing filter, and all other wavelengths of radiation that are not transmitted or absorbed in the radiation polarized through the polarizing filter. reflecting, the second mirror reflects radiation in the operating range of the display in the radiation reflected from the first mirror to the display, and absorbs all other wavelengths that are not reflected in the radiation reflected from the first mirror.

In this case, the second mirror may be a selective dichroic mirror.

In this case, the image projection system may further include a radiation source located behind the display.

In this case, the polarization filter includes a linear s-polarizer with a quarter wave plate, a linear p-polarizer with a quarter wave plate, a circular polarizer with a left polarization, a circular polarizer with a right polarization, a linear s-polarizer, and a linear p - It can be one of the polarizers.

1 is a diagram illustrating an optical scheme of a system for eliminating solar illumination of a display in an on-screen image projection system according to an embodiment.
2 is a diagram illustrating an example in which the polarizing filter is a linear s-polarizer coupled with a quarter wave plate according to an embodiment.
3 is a diagram illustrating an example including an ultraviolet and infrared absorption filter according to an embodiment.
4 is a diagram illustrating an example in which a polarizing filter and an optional dichroic filter are positioned immediately behind a display according to an embodiment.
5 is a diagram illustrating an example in which a first mirror is formed in the form of a selective dichroic mirror according to an exemplary embodiment.
6 is a diagram illustrating an example in which a second mirror is formed in the form of a selective dichroic mirror according to an exemplary embodiment.
7 is a diagram illustrating a schematic transmission spectrum of a selective dichroic filter according to an embodiment.
8A is a diagram illustrating a solar illumination density graph of a display to which a system is not applied according to an embodiment.
8B is a diagram illustrating a solar illumination density graph of a display in the case of a screen projection system including only a linear s-polarizer and a quarter wave plate according to an embodiment.
8C is a diagram illustrating a graph of solar illumination density of a display when an image projection system is applied to a screen including only a linear s-polarizer, a quarter wave plate, and a selective dichroic filter according to an embodiment.
8D uses an image projection system effective to cancel the effects of solar radiation comprising a linear s-polarizer, a quarter wave plate, a dichroic filter and a filter that removes ultraviolet and infrared radiation components according to an embodiment; It is a diagram showing a graph of the solar illumination density of the display.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, since various changes may be made to the embodiments, the scope of the patent application is not limited or limited by these embodiments. It should be understood that all modifications, equivalents and substitutes for the embodiments are included in the scope of the rights.

Terms used in the examples are used for the purpose of description only, and should not be construed as limiting. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present specification, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the embodiment belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

In addition, in the description with reference to the accompanying drawings, the same components are given the same reference numerals regardless of the reference numerals, and the overlapping description thereof will be omitted. In the description of the embodiment, if it is determined that a detailed description of a related known technology may unnecessarily obscure the gist of the embodiment, the detailed description thereof will be omitted.

In addition, in describing the components of the embodiment, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the components from other components, and the essence, order, or order of the components are not limited by the terms. When it is described that a component is “connected”, “coupled” or “connected” to another component, the component may be directly connected or connected to the other component, but between each component another component It will be understood that may also be "connected", "coupled" or "connected".

Components included in one embodiment and components having a common function will be described using the same names in other embodiments. Unless otherwise stated, a description described in one embodiment may be applied to another embodiment, and a detailed description in the overlapping range will be omitted.

Hereinafter, according to an embodiment of the present disclosure A system for projecting a virtual image on a screen which has the effect of canceling the effects of solar radiation will be described in detail with reference to the accompanying Figures 1 to 8D.

The present disclosure not only solves the problem of removing overheating of the display in an apparatus for projecting an image on a screen, but also solves the problem of image distortion of the display caused by illumination of the display by radiation from the surroundings. Any transparent or translucent surface can be used as the screen.

A schematic diagram of a device for projecting an image onto a screen consists of an illumination optic, a display, a projection optic, and a screen. With the aid of projection optics and screens, the display image is redirected to the observer's eye.

When solar radiation, i.e., radiation from the external environment, enters the screen and travels in the opposite direction in the same optical path as the radiation on the display, it will focus on the display and cause the display to overheat, causing the device to fail or overheat. To prevent the display from overheating, the solar light to the display must be removed.

A technical problem directed by the present disclosure is the need to reduce overheating of a display device for projecting a virtual image on a transparent screen by minimizing the solar radiation load on the display.

To solve this problem, you need to do the following:

- some removal of unpolarized solar radiation;

- Partial removal of the visible spectrum of solar radiation;

- removal of the infrared and ultraviolet spectrum of solar radiation;

1 is a diagram illustrating an optical scheme of a system for eliminating solar illumination of a display in an on-screen image projection system according to an embodiment.

The system of Figure 1 is a system for projecting an image onto a transparent screen with the effect of eliminating the effects of solar radiation.

A system (device) for projecting an image on a screen consists of a display 1 , a mirror optical system 2 and a screen 3 . In general, radiation from the display 1 (indicated by a solid arrow) is reflected from the mirror optical system 2 and projected onto the screen 3 . The user sees an image projected from the display 1 to the screen 3 .

The elimination of the effects of solar radiation is realized by means of an optical element which is a polarizing filter 4 , an optional dichroic filter 5 and a coating 6 applied to one of the mirrors.

The optional dichroic filter 5 transmits the ultraviolet component of the solar radiation and the infrared component of the solar radiation as well as the wavelength of the operating radiation (visible light partial region) at which the display 1 operates. A coating 6 applied to one of the mirrors transmits or absorbs ultraviolet and infrared rays and reflects the remaining solar radiation (in the visible region).

In this case, the system for projecting an image onto the screen with the effect of eliminating the effects of solar radiation includes the following elements located in the direction of solar radiation:

screen (3);

a polarizing filter 4 configured to polarize solar radiation;

Selective dichroism configured to transmit radiation (part of visible light region), ultraviolet component of solar radiation and infrared component of solar radiation, and reflect all other wavelengths of solar radiation (visible light region) in the operating range of display 1 sex filter (5);

a first mirror (a) configured to reflect any radiation;

a second mirror (b) configured to transmit or absorb the ultraviolet solar component and the infrared solar component and reflect the remaining solar radiation component;

Display (1).

If the display 1 is transparent it can have a separate lighting part 8 (backlit lighting).

The sun's radiation (the path of the solar radiation beam is indicated by a dotted line and the light path of the display is indicated by a solid line) passes through the screen 3 and falls on a polarizing filter 4, where it is polarized. The polarizer only transmits one linearly polarized part of the solar radiation, eliminating up to 50% of the solar illumination. The polarized radiation strikes a selective dichroic filter 5 that partially cancels out the visible spectrum of solar radiation, and the selective dichroic filter 5 provides radiation in the operating range of the display 1 (part of visible light), the sun It transmits the ultraviolet component of radiation and the infrared component of solar radiation and reflects the remaining visible radiation. Further, the remaining solar radiation (radiation in the operating range of the display 1 , the ultraviolet component of the solar radiation and the infrared component of the solar radiation) is incident on the first mirror a and reflected to the second mirror with the coating 6 applied thereto ( b), which absorbs or transmits the ultraviolet component of solar radiation and the infrared component of solar radiation by means of the coating 6 , and reflects the remainder of the solar radiation remaining after absorption or transmission. The remaining solar radiation is input to the display 1 . In addition, the solar radiation treated in this way has a very low intensity and *?* output, so that heating of the display 1 can be avoided. In addition, the treated solar radiation cannot interfere with the operation of the display 1 and cannot distort the image transmitted from the display 1 to the screen 3 .

As a result, only a very small amount of radiation corresponding to the operating wavelength range of the display 1 among solar radiation is transmitted to the display 1 of FIG. 1 .

2 is a diagram illustrating an example in which the polarizing filter is a linear s-polarizer coupled with a quarter wave plate according to an embodiment.

As shown in FIG. 2 , the polarizing filter 4 may be a linear s-polarizer 4a coupled with a quarter wave plate 4b. The s-polarizer 4a transmits only the s-polarized radiation and absorbs the remaining radiation. Linear s-polarized light passes through the quarter wave plate 4b without attenuation, but its polarization is converted to circular polarization. The narrow spectral lines of the visible spectrum are partially transmitted by the optional dichroic filter 5 and the remainder of the radiation is reflected and no longer passes through, returning to the quarter wave plate 4b 90 It is converted into linearly polarized light by rotating ° and reaches the s-polarizer 4a and is absorbed. The linear s-polarizer 4a and the quarter wave plate 4b are made of a crystalline material (eg quartz) and should be positioned in the projection device along the axial direction and the polarization axis of the display 1 . .

The quarter wave plate 4b is also used to convert elliptically polarized (or unpolarized) radiation from the display into linear s-polarized light. It is also possible to use a p-polarizer instead of an s-polarizer, but it is more preferable to use a linear s-polarizer for higher Fresnel reflection at the surface of the screen 3 . If the display emits elliptically polarized light, it must be converted to s-polarized light to get maximum reflection from the windshield because the reflection coefficient of s-polarized light is much higher than that of p-polarized light. This is because the reflection coefficient and transmittance according to polarization are always determined by the Fresnel formula.

The optional dichroic filter 5 consists of multiple layers, the thickness of which is calculated by the spectral wavelength range. The filter 5 is a glass substrate to which a layer of dielectric materials is applied, and the thickness and number of layers can be calculated in such a way that only certain wavelengths are reflected. Such filters are used in laser resonators, beam splitters, interferometers, and the like. The spectral wavelength range corresponds to the operating wavelength (λn) of the display and wavelengths in the infrared (IR) and ultraviolet (UV) ranges, and the like.

The coating applied to the mirror, which transmits the IR and UV radiation ranges, consists of multiple layers, the thickness of which is calculated according to the transmission of the spectral range. The action of a dielectric mirror is based on the interference of reflected light rays at the boundary between the layers of the dielectric coating. The layer thickness determines the maximum position of the transmission curve. The width of the filter passband and the degree of removal of unnecessary spectral wavelengths are determined by the number of layers. Solar radiation treated in this way is converted into radiation in the selective visible wavelength range, which is the operating wavelength of the display.

3 is a diagram illustrating an example including an ultraviolet and infrared absorption filter according to an embodiment.

Referring to FIG. 3 , a system for projecting an image onto a screen having the effect of canceling the effects of solar radiation on the display comprises:

screen (3);

display (1);

polarizing filter (4);

optional dichroic filter (5);

Ultraviolet/infrared (UV/IR; ultraviolet/infrared) filter 9;

a first mirror (a);

a second mirror (b).

A polarizing filter 4 , an optional dichroic filter 5 , a UV/IR filter 9 , a first mirror a and a second mirror b are positioned between the screen 3 and the display 1 .

Solar radiation indicated by dashed arrows (the path of the sun's rays is indicated by dashed lines and the light path of the display is indicated by solid lines) passes through the screen 3 and falls onto the polarizing filter 4 . The polarizing filter 4 passes only the linearly polarized portion of the solar radiation, removing 50% of the solar *?* illumination. In addition, the radiation falls on a selective dichroic filter 5 which partially removes the visible spectrum of solar radiation. The optional dichroic filter 5 transmits the radiation (part of visible light region) of the operating range of the display 1, the ultraviolet component of solar radiation and the infrared component of solar radiation, and reflects the remaining visible radiation. Further, the radiation falls on a UV/IR filter 9 configured to absorb the ultraviolet and infrared components of the radiation and transmit the remaining wavelengths of radiation (visible light). The UV/IR filter 9 may be located before the polarizing filter 4 or after the optional dichroic filter 5 . After filtering the solar radiation, the remaining radiation (part of visible light) falls on the first mirror (a), which guides the radiation to the second mirror (b). A second mirror b directs the remaining solar radiation to the display.

Also, as in one embodiment, the lighting system may be located behind the display and the polarizing filter 4 may be an s-polarizer combined with a quarter wave plate.

4 is a diagram illustrating an example in which a polarizing filter and an optional dichroic filter are positioned immediately behind a display according to an embodiment.

4 , the system for projecting an image onto a transparent screen with the effect of canceling the effects of solar radiation comprises the following elements:

screen (3);

display (1);

a first mirror (a);

a second mirror (b);

polarizing filter (4);

Optional dichroic filter (5).

Here, the first mirror (a), the second mirror (b), the polarizing filter (4) and the optional dichroic filter (5) are located between the screen (3) and the display (1).

The first mirror a is positioned in such a way that it receives solar radiation passing through the screen 3 (the path of the sun's rays is indicated by a dashed line, and the path of the rays from the display is indicated by a solid line) indicated). Solar radiation is reflected off the first mirror (a) and directed to the second mirror (b). The second mirror b is configured to transmit (or absorb) the ultraviolet component of solar radiation and the infrared component of solar radiation and direct (reflect) all other wavelengths of radiation to the polarizing filter 4 .

As with other embodiments of the present disclosure, the polarizing filter 4 transmits only the linearly polarized portion of solar radiation, removing up to 50% of the sun *?* exposure. The polarized radiation enters the selective dichroic filter 5 and transmits only radiation of a visible light wavelength corresponding to the operating range of the display 1, and removes the visible spectrum of the remaining wavelength region. In this way filtered solar radiation enters the display.

5 is a diagram illustrating an example in which a first mirror is formed in the form of a selective dichroic mirror according to an exemplary embodiment.

Referring to FIG. 5 , in an embodiment in which a selective dichroic mirror is used instead of the selective dichroic filter 5 , the first mirror a is configured as a selective dichroic mirror. In this case, the selective dichroic mirror can be made in the form of a conventional mirror with a selective dichroic coating applied. In this embodiment, solar radiation passes through the screen 3 and enters the polarizing filter 4 .

As with other embodiments, the polarizer only passes the linearly polarized portion of the solar radiation, removing up to 50% of the solar illumination. The polarized radiation enters the first mirror a which reflects only the radiation of the working range of the display 1 , the ultraviolet component of solar radiation and the infrared component of solar radiation and absorbs the remaining visible radiation. In addition, the remaining solar radiation enters the second mirror b to which the coating 6 is applied, and the second mirror b to which the coating 6 is applied absorbs or transmits the ultraviolet and infrared components of the solar radiation, Reflects a portion of the remaining radiation. Also, as in all embodiments, the treated solar radiation has a very low intensity and output and cannot heat the display 1 .

A radiation source (or light source) 8 is used as backlight illumination and may be located behind the display 1 , which illuminates the display 1 .

6 is a diagram illustrating an example in which a second mirror is formed in the form of a selective dichroic mirror according to an exemplary embodiment.

Referring to FIG. 6 , the first mirror (a) is an embodiment configured to transmit or absorb an ultraviolet component of solar radiation and an infrared component of solar radiation and reflect the rest of the spectrum. The second mirror (b) is comprised of a coating configured to reflect radiation in the operating range of the display and to absorb all other wavelengths of solar radiation (the remaining visible radiation), and the second mirror (b) is comprised of an optional dichroic mirror .

In this embodiment, the solar radiation passes through the screen 3 and enters the polarizing filter 4, and like other embodiments, the polarizer passes only the linearly polarized portion of the solar radiation, removing up to 50% of the solar illumination. . The polarized radiation enters the first mirror a on which the coating 6 is applied and absorbs or transmits the ultraviolet and infrared components of the solar radiation, and reflects the remaining portion. The remaining radiation enters the second mirror b which reflects only the radiation in the operating range of the display 1 and absorbs the remaining visible radiation. The remaining solar radiation is input to the display 1 .

A radiation source (or light source 8 ) is used as backlight illumination and may be located behind the display 1 , which illuminates the display 1 .

The solar radiation initially falling on the screen 3 is not polarized. The solar radiation passing through the polarizing filter 4 does not change the spectral composition, but because it passes through only one polarization allowed for a given polarizing filter, the amplitude part of the solar radiation is changed. As is known, unpolarized radiation can be represented by two orthogonal polarizations and the amplitude of all radiation is equally divided into these two orthogonal polarizations. Thus, the polarizing filter 4, which removes unpolarized radiation, transmits only 50% of the solar radiation. Polarizing filter 4 may be a combination of a linear s-polarizer and a quarter wave plate, a combination of a linear p-polarizer and a quarter wave plate, a circular polarizer with a left polarizer or a circular polarizer with a right polarizer, linear It can be an s-polarizer or a combination of p-polarizers. Any combination of polarizing elements may be used, and the polarization axis of the polarizing filter element should correspond to the polarization of the display and the reflectivity of the screen. That is, the polarization axes of the polarizer and the display must match. In addition, since the degree of reflection of radiation from the screen 3 to the user's eyes depends on the polarization of the radiation, it is necessary to consider the consistency of the polarization of the radiation and the type of screen used in the manufacture of the proposed system.

7 is a diagram illustrating a schematic transmission spectrum of a selective dichroic filter according to an embodiment.

1,

2,

3, 즉, 시스템에서 사용되는 디스플레이의 작동 파장, 즉 디스플레이의 스펙트럼 범위를 보여준다.The optional dichroic filter 5 has a transmission spectrum schematically shown in FIG. 7 . The selective dichroic filter passes only wavelengths corresponding to the wavelength at which the display operates, and other wavelengths are reflected by the selective dichroic filter. The selective dichroic filter removes about 17.5% of solar radiation. That is, only radiation in the display operating range is transmitted excluding radiation in the visible region of the solar radiation spectrum. 7 shows the wavelength through which the optional dichroic filter passes;

One,

2,

3, that is, the operating wavelength of the display used in the system, ie the spectral range of the display.

When the polarizing filter 4 and the optional dichroic filter 5 are used, the white balance of the virtual image projected by the display onto the transparent screen is improved. When using a display with broad spectrum radiation, the virtual image obtained from a transparent screen will not have sufficient contrast. Because a color image is formed of three components: spectrum R, G, and B, the narrower the band of each spectrum, the more accurate the color rendering of the virtual image. To increase contrast and improve white balance, polarizing filters and optional dichroic filters can be designed to pass only the specific essential operating wavelength range of the display.

The second mirror (b) or filter is configured to absorb or transmit the ultraviolet component of solar radiation and the infrared component of solar radiation, and removes about 28.5% of the solar radiation. This element is a substrate with a multilayer thin-film coating or a filter that transmits, absorbs or reflects the ultraviolet (UV) and infrared (IR) parts of the spectrum and reflects or transmits the visible part of the spectrum. can be Also, this element could be made to absorb only IR radiation, and the manufacture of such a filter (or mirror) would be much cheaper than making a filter or mirror that absorbs both ultraviolet and infrared components.

The first mirror (a) may be a fully (or partially) reflective mirror with an aspherical surface, a flat surface or any surface shape. Other suitable optical elements and lens systems may be used instead of mirrors.

The screen 3 on which the image from the display is projected may be a car windshield, may be a translucent screen, and may be a screen or combiner that combines a real image and a virtual image used in virtual reality helmets. ), a partially reflecting mirror, or a holographic optical element.

The display 1 may emit elliptically polarized or non-polarized light. The display may be:

- LCD (liquid crystal) display;

- Diffuser combined with: LCoS display (non-polarized light), DLP display with digital lighting processing; Microelectromechanical systems (MEMS) displays.

A radiation source may be as follows.

- backlight unit with RGB (or white) LEDs;

- RGB (or white) LED lighting system;

- laser projection system;

- halogen lamps.

It should be noted that the characteristics of all elements of the system are selected in a manner consistent with the characteristics of the display being used.

8A is a diagram illustrating a solar illumination density graph of a display to which a system is not applied according to an embodiment.

When the system proposed in the present disclosure is not used, the power of solar radiation incident on the display is 50 W, and the maximum illumination density is 21.2 kW/m 2 .

8A - 8D , the X axis corresponds to the X coordinate (mm) of the display, and 0 is generally the center of the screen along the X axis. The Y-axis corresponds to the illumination density (W/mm2).

8B is a diagram illustrating a solar illumination density graph of a display for a screen projection system including a linear s-polarizer and a quarter wave plate according to an embodiment. In this case, the power of the solar radiation is much lower at 24.4 W, and the illumination density is 10.3 kW/m2.

8C is a graph illustrating a solar illumination density of a display for the application of an image projection system to a screen including a linear s-polarizer, a quarter wave plate and an optional dichroic filter, according to an embodiment. . In this case, the power of the solar radiation is much lower at 15.7 W, and the illumination density is 6.6 kW/m2.

8D is an image projection system effective to cancel the effects of solar radiation comprising a linear s-polarizer, a quarter wave plate, a dichroic filter, and a filter that removes ultraviolet and infrared radiation components according to an embodiment; It is a diagram showing a graph of the solar illumination density of the display for the case of In this case, the power of solar radiation is much lower at 2.07 W, and the illumination density is 0.9 kW/m2.

The content proposed in the present disclosure may be used in a projection display, a navigation system, an outdoor advertisement display, etc. in addition to a head-up display (HUD) for a vehicle.

The proposed system may be a body embedded in a dashboard when used in a car dashboard. This housing contains all the components of the proposed system, and the housing may have a window for outputting radiation from the display to the windshield.

As described above, although the embodiments have been described with reference to the limited drawings, those skilled in the art may apply various technical modifications and variations based on the above. For example, the described techniques are performed in a different order than the described method, and/or the described components of the system, structure, apparatus, circuit, etc. are combined or combined in a different form than the described method, or other components Or substituted or substituted by equivalents may achieve an appropriate result.

Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

Claims (18)

screen;
polarizing filter;
optional dichroic filter;
a first mirror;
a second mirror; and
display
including,
wherein the polarizing filter, the selective dichroic filter, the first mirror, and the second mirror are positioned between the screen and the display;
the polarizing filter polarizes solar radiation passing through the screen;
The optional dichroic filter is located behind the polarizing filter and transmits radiation of the operating range of the display in radiation polarized through the polarizing filter, the ultraviolet component of the radiation and/or the infrared component of the radiation, and all other non-transmitted radiation. reflect the wavelength of radiation,
the first mirror reflects the radiation that has passed through the selective dichroic filter to the second mirror;
The second mirror transmits or absorbs the infrared component of the radiation and/or the ultraviolet component of the radiation reflected from the first mirror, and transmits radiation having a remaining wavelength that is not transmitted or absorbed in the radiation reflected from the first mirror. leading to display
image projection system.
According to claim 1,
a radiation source located behind the display
An image projection system further comprising a.
According to claim 1,
The polarizing filter is
Linear s-polarizer with quarter wave plate,
Linear p-polarizer with quarter wave plate,
circular polarizer with left polarization,
circular polarizer with right polarization,
linear s-polarizer,
One of the linear p-polarizers is
image projection system.
screen;
polarizing filter;
optional dichroic filter;
filter;
a first mirror;
a second mirror; and
display
including,
wherein the polarizing filter, the selective dichroic filter, the first mirror, and the second mirror are located between the screen and the display;
the polarizing filter polarizes solar radiation passing through the screen;
The optional dichroic filter is located behind the polarizing filter and transmits radiation in the operating range of the display, the ultraviolet component of the radiation and/or the infrared component of the radiation among the radiation polarized through the polarizing filter, and reflects all other wavelengths of radiation. do,
the filter absorbs the ultraviolet and infrared components of radiation and transmits all other unabsorbed wavelengths of radiation;
the first mirror reflects the radiation that has passed through all of the polarizing filter, the selective dichroic filter and the filter to the second mirror;
The second mirror guides the radiation reflected from the first mirror to the display.
image projection system.
5. The method of claim 4,
a radiation source located behind the display
An image projection system further comprising a.
5. The method of claim 4,
The filter is
located in front of the polarizing filter, or located after the optional dichroic filter
image projection system.
5. The method of claim 4,
The polarizing filter is
Linear s-polarizer with quarter wave plate,
Linear p-polarizer with quarter wave plate,
circular polarizer with left polarization,
circular polarizer with right polarization,
linear s-polarizer,
One of the linear p-polarizers is
image projection system.
screen;
a first mirror;
a second mirror;
polarizing filter;
optional dichroic filter; and
display
including,
the first mirror, the second mirror, the polarization filter, and the optional dichroic filter are positioned between the screen and the display;
the first mirror reflects solar radiation that has passed through the screen to the second mirror;
the second mirror transmits or absorbs the ultraviolet component of the solar radiation and/or the infrared component of the solar radiation, and reflects radiation having a remaining wavelength that is not transmitted or absorbed in the solar radiation to the polarizing filter;
the polarizing filter polarizes the radiation reflected from the second mirror;
The selective dichroic filter is located behind the polarizing filter, transmits radiation in the operating range of the display from radiation polarized through the polarizing filter and guides it to the display, and the remaining wavelengths not transmitted by the selective dichroic filter reflect the radiation of
image projection system.
9. The method of claim 8,
a radiation source located behind the display
An image projection system further comprising a.
9. The method of claim 8,
The polarizing filter is
Linear s-polarizer with quarter wave plate,
Linear p-polarizer with quarter wave plate,
circular polarizer with left polarization,
circular polarizer with right polarization,
linear s-polarizer,
One of the linear p-polarizers is
image projection system.
screen;
polarizing filter;
a first mirror;
a second mirror; and
display
including,
the polarizing filter, the first mirror, and the second mirror are positioned between the screen and the display;
The polarizing filter polarizes solar radiation,
the first mirror reflects radiation in the display operating range in radiation polarized through the polarizing filter, an ultraviolet component of the polarized radiation and/or an infrared component of the polarized radiation to the second mirror, and the polarizing filter absorbs radiation of all other wavelengths that are not reflected among the radiation polarized through
The second mirror transmits or absorbs the ultraviolet component of the radiation reflected from the first mirror and/or the infrared component of the radiation reflected from the first mirror, and is not transmitted or absorbed in the radiation reflected from the first mirror. reflecting all other wavelengths towards the display.
image projection system.
12. The method of claim 11,
wherein the first mirror is a selective dichroic mirror
image projection system.
12. The method of claim 11,
a radiation source located behind the display
An image projection system further comprising a.
12. The method of claim 11,
The polarizing filter is
Linear s-polarizer with quarter wave plate,
Linear p-polarizer with quarter wave plate,
circular polarizer with left polarization,
circular polarizer with right polarization,
linear s-polarizer,
One of the linear p-polarizers is
image projection system.
screen;
polarizing filter;
a first mirror;
a second mirror; and
display
including,
the polarizing filter, the first mirror, and the second mirror are positioned between the screen and the display;
The polarizing filter polarizes solar radiation,
The first mirror transmits or absorbs an ultraviolet component of radiation polarized through the polarizing filter and/or an infrared component of radiation polarized through the polarization filter, and transmits or absorbs other components that are not transmitted or absorbed in the radiation polarized through the polarizing filter. reflects radiation of all wavelengths to the second mirror;
the second mirror reflects radiation in the operating range of the display to the display in radiation reflected from the first mirror, and absorbs all other unreflected wavelengths in radiation reflected from the first mirror.
image projection system.
16. The method of claim 15,
wherein the second mirror is a selective dichroic mirror
image projection system.
16. The method of claim 15,
a radiation source located behind the display
An image projection system further comprising a.
16. The method of claim 15,
The polarizing filter is
Linear s-polarizer with quarter wave plate,
Linear p-polarizer with quarter wave plate,
circular polarizer with left polarization,
circular polarizer with right polarization,
linear s-polarizer,
One of the linear p-polarizers is
image projection system.

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