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EP-4431999-B1 - IMAGE GENERATION APPARATUS, DISPLAY DEVICE AND VEHICLE

EP4431999B1EP 4431999 B1EP4431999 B1EP 4431999B1EP-4431999-B1

Inventors

  • CHEN, Yanzhe
  • FANG, Yuanrong
  • FANG, Zhifang

Dates

Publication Date
20260506
Application Date
20220906

Claims (15)

  1. A picture generation apparatus (100), comprising: a light source (110), configured to provide a light beam; and a beam splitting unit (120), configured to separate a linearly polarized polychromatic light from the light beam, and input the linearly polarized polychromatic light into a spatial light modulator (130), wherein the spatial light modulator (130) is configured to perform light modulation on the linearly polarized polychromatic light based on picture data, characterized in that the spatial light modulator (130) is further configured to input a modulated linearly polarized polychromatic light into a polarization conversion unit (140); and the polarization conversion unit (140) is configured to convert a polarization direction of a first colored light in the modulated linearly polarized polychromatic light, and output an imaging light, wherein the imaging light comprises the first colored light and a second colored light whose polarization directions are perpendicular to each other.
  2. The picture generation apparatus (100) according to claim 1, wherein the polarization conversion unit (140) comprises a retarder stack filter, RSF, and the RSF is configured to rotate the polarization direction of the first colored light by 90°.
  3. The picture generation apparatus (100) according to claim 1 or 2, wherein the first colored light comprises a red light, and the second colored light comprises a blue light and/or a green light; or the first colored light comprises a blue light and/or a green light, and the second colored light comprises a red light.
  4. The picture generation apparatus (100) according to any one of claims 1 to 3, wherein the beam splitting unit (120) comprises: a polarization beam splitter (1211, 1212), configured to guide the linearly polarized polychromatic light to the spatial light modulator (130), wherein the linearly polarized polychromatic light is a P light; the spatial light modulator (130) is configured to perform light modulation on the linearly polarized polychromatic light based on the picture data, wherein the modulated linearly polarized polychromatic light is an S light; and the polarization beam splitter (1211, 1212) is further configured to guide the modulated linearly polarized polychromatic light to the polarization conversion unit (140).
  5. The picture generation apparatus (100) according to claim 4, wherein the beam splitting unit (120) further comprises: a polarizer (122), wherein the polarizer (122) is located on a light path between the light source (110) and the polarization beam splitter (1212), and the polarizer (122) is configured to separate the P light from the light beam to obtain the linearly polarized polychromatic light.
  6. The picture generation apparatus (100) according to any one of claims 1 to 3, wherein the beam splitting unit (120) comprises: a polarization beam splitter (1211, 1212), configured to guide the linearly polarized polychromatic light to the spatial light modulator (130), wherein the linearly polarized polychromatic light is an S light; the spatial light modulator (130) is configured to perform light modulation on the linearly polarized polychromatic light based on the picture data, wherein the modulated linearly polarized polychromatic light is a P light; and the polarization beam splitter (1211, 1212) is further configured to guide the modulated linearly polarized polychromatic light to the polarization conversion unit (140).
  7. The picture generation apparatus (100) according to claim 6, wherein the beam splitting unit (120) further comprises: a polarizer (122), wherein the polarizer is located on a light path between the light source (110) and the polarization beam splitter (1212), and the polarizer (122) is configured to separate the S light from the light beam to obtain the linearly polarized polychromatic light.
  8. The picture generation apparatus (100) according to any one of claims 4 to 7, wherein the polarization beam splitter (120) comprises a wire grid (1212) and/or a polarization beam splitting prism (1211).
  9. The picture generation apparatus (100) according to any one of claims 1 to 3, wherein the spatial light modulator (130) is specifically configured to: perform light modulation on the linearly polarized polychromatic light based on the picture data, and transmit the modulated linearly polarized polychromatic light.
  10. The picture generation apparatus (100) according to claim 9, wherein the beam splitting unit (120) further comprises: a polarizer (122), configured to separate a P light or an S light from the light beam to obtain the linearly polarized polychromatic light.
  11. The picture generation apparatus (100) according to any one of claims 1 to 10, wherein the spatial light modulator (130) comprises at least one of a liquid crystal on silicon LCOS, a liquid crystal display LCD (132), an organic light-emitting diode OLED, a micro-light-emitting diode micro-LED, a digital micromirror device DMD, and a micro-electro-mechanical system MEMS.
  12. A display device, comprising a host central processing unit (1101) and the picture generation apparatus (100) according to any one of claims 1 to 11, wherein the host central processing unit (1101) is configured to send picture data to the spatial light modulator (130).
  13. A vehicle, comprising a display device and a windshield, wherein the display device comprises a picture generation apparatus (100) according to any one of claims 1 to 11, wherein the picture generation apparatus (100) is configured to project an imaging light onto the windshield.
  14. The vehicle according to claim 13, wherein a first colored light in the imaging light is a red light, and the first colored light is an S light projected onto the windshield.
  15. The vehicle according to claim 13, wherein a first colored light in the imaging light is a blue light and/or a green light, and the first colored light is a P light projected onto the windshield.

Description

TECHNICAL FIELD Embodiments of this application relate to the picture display field, and in particular, to a picture generation apparatus, a display device, and a vehicle. BACKGROUND CN 105 824 177 A describes a liquid crystal liquid crystal projection system. US 2021/333545 A1 describes a head-up display apparatus. In a projection display technology, a display may be a reflective device. A display device projects an imaging light onto the reflective device like glass. The reflective device reflects the imaging light to human eyes, to implement projection of the imaging light to human eyes. During projection of a panchromatic imaging light from inside the display device to human eyes, because different colored lights have different wavelength ranges, display effect of the different colored lights is different, and imaging effect is affected. For example, parameters such as light intensity and contrast of a part of colored lights in the imaging light are greatly different from those of other colored lights. This results in uneven color rendering, and a like phenomenon. SUMMARY Embodiments of this application provide a picture generation apparatus, a display device, and a vehicle according to the independent claims, to improve color rendering evenness and imaging effect of a picture on a reflective device. According to a first aspect, an embodiment of this application provides a picture generation apparatus. The picture generation apparatus includes a light source, a beam splitter, a spatial light modulator, and a polarization conversion unit. The light source is configured to provide a light beam. The beam splitting unit is configured to separate a linearly polarized polychromatic light from the light beam, and input the linearly polarized polychromatic light into the spatial light modulator. The spatial light modulator is configured to perform light modulation on the linearly polarized polychromatic light based on picture data, and input a modulated linearly polarized polychromatic light into the polarization conversion unit. The polarization conversion unit is configured to convert a polarization direction of a first colored light in the modulated linearly polarized polychromatic light, and output an imaging light, where the imaging light includes the first colored light and a second colored light whose polarization directions are perpendicular to each other. In this embodiment of this application, polarization directions of colored lights in the linearly polarized polychromatic light separated by the beam splitting unit are the same. The polarization conversion unit converts the polarization direction of the first colored light in the linearly polarized polychromatic light, so that the polarization directions of the first colored light and the second colored light in the imaging light are perpendicular to each other. Therefore, different operations may be performed on the first colored light and the second colored light based on the polarization directions or the first colored light and the second colored light pass through different light paths, to avoid poor display effect of the first colored light or the second colored light caused by performing a same operation or passing through a same light path. This improves the display effect of the first colored light or the second colored light, and improves color rendering evenness and imaging effect. For example, in a vehicle-mounted HUD scenario, a coating in a windshield is used as a reflective device. The imaging light is incident to the windshield by using a P light, and is imaged in human eyes through reflection of the coating. However, some coatings have low reflectivity and high absorbance on a red P light. This results in low color rendering of a red light in imaging and uneven color rendering of the imaging. According to the picture generation apparatus provided in this embodiment of this application, a red light that is used as the first colored light is an S light, of the windshield, projected onto the windshield, and another colored light (the second colored light) is a P light projected onto the windshield. Based on different properties of the P light and the S light, the red light (the first colored light) is reflected on two boundary planes of the windshield and the air, and the another colored light (the second colored light) is reflected on the coating in the windshield. This avoids a light intensity defect of the red light caused by reflection of the red light on the coating, and improves color rendering evenness of the imaging. In an optional implementation, the polarization conversion unit includes a retarder stack filter (retarder stack filter, RSF). The RSF is configured to rotate the polarization direction of the first colored light by 90°. The RSF changes a polarization status of the first colored light through a phase delay, and has a low loss to the first colored light and other colored lights in a polychromatic light source. Theref