Abstract: This invention relates to a cold mirror for a head-up display apparatus and provides a cold mirror that enables suppression of a phenomenon of change in color tone of an image depending on a position from which the image is viewed. This invention also provides a head-up display apparatus including the cold mirror. In a head-up display apparatus, display light of an image displayed on a display is reflected by a cold mirror and a reflected image of the image is viewed by a viewer. A relationship between an incident wavelength and a reflection phase difference in the cold mirror is set so that the reflection phase difference falls within a range of 180±60 degrees for an entire visible wavelength range of 420 to 680 nm.

Abstract: This invention relates to a cold mirror for a head-up display apparatus and provides a cold mirror that enables suppression of a phenomenon of change in color tone of an image depending on a position from which the image is viewed. This invention also provides a head-up display apparatus including the cold mirror. In a head-up display apparatus, display light of an image displayed on a display is reflected by a cold mirror and a reflected image of the image is viewed by a viewer. A relationship between an incident wavelength and a reflection phase difference in the cold mirror is set so that the reflection phase difference falls within a range of 180±60 degrees for an entire visible wavelength range of 420 to 680 nm.

Abstract: Disclosed is a display device at a low cost which enhances the color purity of light to be projected, and which resists deterioration due to ambient light such as infrared ray. This display device includes an LED, an optical member for selectively outputting light components, of which wavelength is a predetermined minimum-limit wavelength or longer, from incident light, and a mirror for selectively reflecting light components, of which wavelength is a predetermined maximum-limit wavelength or shorter, from irradiated light. One of the optical member or the mirror receives light directly from the LED, and outputs it to the other. Subsequently, the other receives the light from one of the optical member and the mirror, and outputs it.

Abstract: Disclosed is a display device at a low cost which enhances the color purity of light to be projected, and which resists deterioration due to ambient light such as infrared ray. This display device includes an LED, an optical member for selectively outputting light components, of which wavelength is a predetermined minimum-limit wavelength or longer, from incident light, and a mirror for selectively reflecting light components, of which wavelength is a predetermined maximum-limit wavelength or shorter, from irradiated light. One of the optical member or the mirror receives light directly from the LED, and outputs it to the other. Subsequently, the other receives the light from one of the optical member and the mirror, and outputs it.