JP2019003153A - Light source unit, video generating device, and head-up display - Google Patents

Abstract

To provide a video generating device and a head-up display that can reproduce a desired hue while preventing a reduction in luminance, and a light source unit that can be suitably used for the video generating device.SOLUTION: A light source unit comprises a light source, and a reflector that has a cylindrical shape with an opening and includes a mirror surface having a color adjustment film laminated on its inner surface, where the light source is arranged inside the reflector.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light source unit, a video generation device, and a head-up display.

A head-up display (hereinafter sometimes referred to as HUD) that projects an image generated by an image generation device including a liquid crystal panel or the like onto an automobile front window or the like via an optical system and provides an image to an observer. It has been known.
As an example, Patent Document 1 discloses a display including a specific liquid crystal display element, a specific mirror arranged to be inclined with respect to the liquid crystal display element, and a specific light source arranged behind the liquid crystal display element. An apparatus is disclosed. According to Patent Document 1, a display image having a desired color can be output while suppressing a decrease in luminance by using a mirror that transmits light in a predetermined wavelength region and reflects other light. .

JP 2005-338325 A

  HUDs are required to have higher brightness. On the other hand, in particular, in-vehicle HUDs are required to have high reliability such as heat resistance, so that types of usable light sources and liquid crystal panels are limited. Since the color reproduction range is largely determined by the combination of the light source and the liquid crystal panel included in the video generation apparatus, the current color reproduction range of the in-vehicle HUD has a low degree of freedom, and there is a problem that a desired color cannot be obtained.

  Since the technique of Patent Document 1 uses a specific mirror to display a desired color, it is necessary to change the image light to a desired color by a single reflection. Therefore, there is a problem that the degree of design difficulty is high, the color adjustment is limited, and the degree of freedom in color adjustment is low.

  The present invention has been made in view of the above circumstances, and can be suitably used for a video generation device and a head-up display capable of reproducing a desired color while suppressing a decrease in luminance, and the video generation device. An object is to provide a light source unit.

The present invention comprises a light source;
A cylindrical shape having an opening, and a reflective material having a mirror surface with a color adjustment film laminated on the inner surface,
A light source unit is provided in which the light source is disposed inside the reflector.

  The present invention provides a video generation device including the light source unit according to the present invention and a lens and a liquid crystal panel on the opening side of the light source unit.

  The present invention also provides a video generation device according to the present invention and a head-up display including an optical system on the video light output side of the video generation device.

  ADVANTAGE OF THE INVENTION According to this invention, the video production | generation apparatus and head-up display which can reproduce a desired color while suppressing the fall of a brightness | luminance, and the light source unit which can be used conveniently for the said video production | generation apparatus can be provided.

FIG. 1 is a schematic sectional view showing an example of a light source unit of the present invention. FIG. 2 is a schematic cross-sectional view showing an example of the video generation apparatus of the present invention. FIG. 3 is a schematic cross-sectional view showing an example of the head-up display of the present invention. FIG. 4 is a graph showing an example of the spectral reflectance of the mirror surface on which the color reflection films are laminated.

  Hereinafter, a light source unit, a video generation device, and a head-up display according to the present invention will be described in order with reference to the drawings. For the sake of explanation, the scale of each member in the drawings may differ greatly. In the drawings and the like, the same or equivalent elements are denoted by the same reference numerals, and redundant description is omitted.

  First, an embodiment of a light source unit will be described with reference to FIG. The light source unit 10 of the present embodiment includes a light source 1 and a reflector 2 having a mirror surface 4 having an opening 6 through which light is emitted and having a color adjustment film 5 laminated on the inner surface. The reflector 2 is disposed inside.

The light source 1 is a light emitter that emits light itself. The light source 1 is disposed inside a reflector 2 to be described later, and as indicated by an optical path 9, at least part of the light emitted from the light source 1 is reflected by the reflector 2 at least once and exits from the opening 6. . The light source 1 is preferably a light emitting diode (LED) from the viewpoint of high luminance and miniaturization, and is preferably a white LED from the viewpoint of the color reproduction range. Moreover, it is preferable that the light emission surface of LED is a plane from the point of the ease of adjustment of a color. One light source 1 may be used, or two or more light sources may be used.
When an LED is used as the light source 1, the LED may be provided on the substrate 7. When providing 2 or more LED on the board | substrate 7, it is preferable to arrange | position on the common plane of the light emission surface of each LED. The substrate 7 usually has a circuit for supplying power to the LEDs. The surface of the substrate 7 may be a mirror surface or may not be a mirror surface.

  The reflecting material 2 has an opening 6 and has a mirror surface 4 in which a color adjusting film 5 is laminated on the inner surface. A diffusion plate 8 may be further disposed on the opening 6. By using the diffusing plate 8, the in-plane uniformity of the luminance of light incident on the liquid crystal panel is improved. The diffusion plate 8 can be appropriately selected from known diffusion plates.

The shape of the reflecting material 2 may be any shape that reflects at least part of the light emitted from the light source 1. From the viewpoint of in-plane uniformity of the luminance of light on the exit surface, the shape of the reflector 2 is preferably a cylindrical shape with a constant cross section. The cylindrical shape may be a cylindrical shape or an elliptical cylindrical shape, or may be a polygonal rectangular tube shape. It is preferable that the shape of the reflecting material 2 is a square tube type in which the emission surface is the same type as a liquid crystal panel described later.
When the reflecting material 2 has a cylindrical shape, it is preferable that one end of the tube is an opening 6 and the light source 1 is disposed at one end facing the opening 6. Moreover, when the reflecting material 2 is cylindrical, it is preferable that the mirror surface 4 is arrange | positioned perpendicularly | vertically with respect to the issuing surface of the light source 1. FIG.
When the reflecting material 2 has a cylindrical shape, the vertical length from the center of the light source to the color adjustment film surface is D, and the length L of the cylinder is dependent on the incident angle of the spectral reflectance of the color adjustment film 5. In view of the above, it is desirable that D · tan 5 ° <L <D · tan 25 °. By setting L within the above range, most of the light incident on the mirror surface has an incident angle in the range of 5 ° to 25 °. If the incident angle of light when reflected by the color adjustment film is about 5 °, the spectral reflectance is almost the same as that of vertical incidence. On the other hand, when the incident angle is 25 ° or more, the blue shift of the spectral reflectance becomes remarkable, and a desired color may not be obtained.

  The method for forming the mirror surface 4 of the reflector 2 is not particularly limited, and the substrate 3 itself may be mirror-finished, a metal film may be formed on the substrate 3, and the metal film surface may be used as the mirror surface 4. When the substrate 3 is mirror-finished, the material of the substrate 3 is preferably a metal, and particularly preferably aluminum. On the other hand, when forming a metal film on the base material 3, the material of the base material 3 is not specifically limited, A metal may be sufficient and resin, such as a polycarbonate, glass, etc. may be sufficient. The metal of the metal film used as the mirror surface 4 is preferably a metal having a high visible light reflectivity. For example, aluminum, nickel, silver and the like are preferable, and aluminum is particularly preferable from the viewpoint of heat resistance. The method for forming the metal film can be appropriately selected from known methods such as vapor deposition, sputtering, and transfer of metal foil.

In the present invention, the color adjustment film 5 is laminated on the mirror surface 4. Thereby, the spectral reflectance of the inner surface of the reflecting material 2 is adjusted, and the light emitted from the light source 1 is reflected by the inner surface of the reflecting material 2, so that it can be adjusted to a desired color.
The material of the color adjustment film 5 is preferably a dielectric film having a high visible light transmittance and a high refractive index. Examples of the dielectric film include silicon oxide (SiO ₂ ), titanium oxide (TiO ₂ ), and zirconium oxide (ZrO ₂ ). The color adjusting film 5 may be composed of only one layer or a combination of two or more layers, but in the present invention, it is preferably a single layer.
The film thickness of the color adjustment film is not particularly limited, but is preferably 50 nm or more and preferably 400 nm or less from the viewpoint of color adjustment. When the film thickness of the color adjustment film is 50 nm or less, the color adjustment film hardly affects the spectral reflectance of the mirror surface of the substrate 3 or the metal film, and the color adjustment effect may not be obtained. When the film thickness of the color adjustment film exceeds 400 nm, the spectral reflectance is likely to be a mixture of a number of high and low reflectance wavelengths in the visible light range, and color adjustment may be difficult.

  The method for forming the color adjustment film 5 is not particularly limited, and can be appropriately selected from known methods such as vapor deposition and sputtering.

A light source unit that emits light of a desired color can be obtained by appropriately combining the thickness and material of the color adjustment film 5. An example will be described with reference to FIG. FIG. 4 is a graph showing an example of the spectral reflectance of a mirror surface on which a color reflection film is laminated. Specifically, two reflective materials in which a silicon oxide film having a film thickness of 50 nm and 200 nm as a color adjusting film is formed on a mirror surface of aluminum are each irradiated with light using a white LED as a light source, and the reflected light is spectrophotometrically measured. The result measured using a meter is shown. As shown in FIG. 4, when the thickness of the silicon oxide film is 50 nm, the wavelength dependency of the light reflectance in the visible light region (wavelength 380 nm to 780 nm) is small, and the light emitted from the light source unit is a light source. Easy to reproduce colors. On the other hand, when the thickness of the silicon oxide film is 200 nm, the reflectance of light near the wavelength of 530 nm can be increased, and light with a green color emphasized near the wavelength of 530 nm can be obtained as light emitted from the light source unit. Can do.
Although the use of the light source unit of the present invention is not particularly limited, it is particularly suitable for use as a video generation device and a head-up display described later.

An embodiment of a video generation device will be described with reference to FIG. The image generation apparatus 20 of the present embodiment includes the light source unit 10 and a lens 11 and a liquid crystal panel 12 on the opening 6 side of the light source unit 10.
The lens 11 has the purpose of controlling the orientation of the light emitted from the opening 6 of the light source unit 10 and controlling the angle of the light emitted through the liquid crystal panel 12, and is appropriately selected from known lenses. Can be used. The liquid crystal panel 12 is not particularly limited, and a publicly known configuration can be appropriately selected and used as a liquid crystal panel generally used for HUD.

  Next, an embodiment of a head-up display will be described with reference to FIG. The head-up display 100 according to the present embodiment includes the video generation device 20 and an optical system on the video light emission side of the video generation device. In the example of FIG. 3, the optical system includes the reflecting mirror 21 and the concave mirror 22, but is not particularly limited to this configuration. In the example of FIG. 3, the reflecting mirror 21 is used to fold the optical system and reduce the size of the apparatus. The concave mirror 22 is used for enlarging and projecting the image light emitted from the image generation device 20.

DESCRIPTION OF SYMBOLS 1 Light source 2 Reflective material 3 Base material 4 Mirror surface 5 Color adjustment film | membrane 6 Opening part 7 Board | substrate 8 Diffusion plate 9 Optical path 10 Light source unit 11 Lens 12 Liquid crystal panel 20 Image generation device 21 Reflector 22 Concave mirror 100 Head-up display

Claims (8)

A light source;
A cylindrical shape having an opening, and a reflective material having a mirror surface with a color adjustment film laminated on the inner surface,
A light source unit in which the light source is disposed inside the reflector.   The light source unit according to claim 1, wherein the light source is a white light emitting diode having a light emitting surface.   The light source unit according to claim 2, wherein the mirror surface is disposed perpendicular to the light emitting surface.   The light source unit according to claim 1, wherein the color adjustment film is a dielectric film.   The light source unit according to claim 1, wherein the color adjustment film has a thickness of 50 nm or more and 400 nm or less. When the vertical distance D from the center of the light source to the surface of the color adjustment film is the length L of the cylindrical shape,
D ・ tan5 ° <L <D ・ tan25 °
The light source unit according to claim 1, wherein the light source unit satisfies the following conditions.   An image generation apparatus comprising: the light source unit according to claim 1; and a lens and a liquid crystal panel on the opening side of the light source unit.   8. A head-up display comprising: the video generation device according to claim 7; and an optical system on a video light emission side of the video generation device.

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