ELECTRONIC MIRROR DEVICE

• US 20170203693A1
• Filed: 05/12/2015
• Published: 07/20/2017
• Est. Priority Date: 06/03/2014
• Status: Abandoned Application

• Current Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Inventors: OISHI, TOSHIHARU
• Application Number:
  US15/313,078
• Publication Number:
  US 20170203693A1
• Time in Patent Office: Days
• CPC Class Codes: B60R 1/00 Optical viewing arrangements; Real-time viewing arrangements for drivers or passengers using optical image capturing systems, e.g. cameras or video systems specially adapted for use in or on vehicles
• CPC Class Codes: B60R 1/04 mounted inside vehicle B60R1/025, B60R1/08 take precedence
• CPC Class Codes: B60R 1/08 involving special optical features, e.g. avoiding blind spots , e.g. convex mirrors; Side-by-side associations of rear-view and other mirrors B60R1/025, B60R1/10 take precedence
• CPC Class Codes: B60R 1/12 Mirror assemblies combined with other articles, e.g. clocks
• CPC Class Codes: B60R 1/26 to the rear of the vehicle
• CPC Class Codes: B60R 2001/1215 with information displays
• CPC Class Codes: B60R 2300/20 characterised by the type of display used
• CPC Class Codes: B60R 2300/8066 for monitoring rearward traffic
• CPC Class Codes: G02F 1/133509 Filters, e.g. light shielding masks
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence
• CPC Class Codes: G02F 1/133543 Cholesteric polarisers
• CPC Class Codes: G02F 1/133562 on the viewer side
• CPC Class Codes: G02F 1/13363 Birefringent elements, e.g. for optical compensation
• CPC Class Codes: G02F 1/133638 Waveplates, i.e. plates with a retardation value of lambda/n
• CPC Class Codes: G02F 1/137 characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering
• CPC Class Codes: G02F 2201/343 cholesteric liquid crystal reflector
• CPC Class Codes: G09F 9/00 Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the variable information is permanently attached to a movable support G09F11/00; abacus G06C1/00; slide-rules G06G1/00
• CPC Class Codes: G09F 9/35 being liquid crystals G09F9/302 takes precedence; liquid crystal materials C09K19/00; liquid crystal panels comprising a number of electrodes in a single cell per se G02F1/13

Abstract

An electronic mirror device for displaying an image captured by a camera mounted to a vehicle includes a liquid crystal display having a display surface, a retarder, and a cholesteric liquid crystal layer. The retarder is disposed opposite the display surface of the liquid crystal display, and circularly polarizes a liquid crystal image emitted from the liquid crystal display. The cholesteric liquid crystal layer is disposed on the opposite side of the retarder from the liquid crystal display. The liquid crystal image circularly polarized by the retarder passes through the cholesteric liquid crystal layer.

Claims

1. An electronic mirror device for displaying an image captured by a camera mounted to a vehicle, the electronic mirror device comprising:

a liquid crystal display having a display surface;

a retarder disposed opposing the display surface of the liquid crystal display, the retarder circularly polarizing a liquid crystal image emitted from the liquid crystal display; and

a cholesteric liquid crystal layer disposed on an opposite side of the retarder from the liquid crystal display, the cholesteric liquid crystal layer transmitting the liquid crystal image circularly polarized by the retarder.

2. The electronic mirror device according to claim 1, wherein

the retarder is a quarter-wave retarder having a slow-phase axis tilted 45 degrees from an absorption axis of the liquid crystal display, and

the cholesteric liquid crystal layer is configured to transmit the liquid crystal image circularly polarized in a same direction as being circularly polarized by the retarder.

3. The electronic minor device according to claim 1, further comprising a filter that controls an amount of light reflection, the filter being disposed on an opposite side of the cholesteric liquid crystal layer from the retarder.

4. The electronic minor device according to claim 1, wherein when the liquid crystal display is ON, the cholesteric liquid crystal layer is kept in a state of transmitting one of right-circularly polarized light and left-circularly polarized light, and reflecting the other one of the right-circularly polarized light and the left-circularly polarized light.

5. The electronic mirror device according to claim 4, wherein when the liquid crystal display is OFF, the cholesteric liquid crystal layer has a same reflectivity for outside light as when the liquid crystal display is ON.

6. The electronic minor device according to claim 4, wherein the cholesteric liquid crystal layer has a reflectivity of 0.4 or greater for outside light.

7. The electronic minor device according to claim 1, wherein when the cholesteric liquid crystal layer has a reflectivity X where 0<

X<

1 for outside light, and the liquid crystal image emitted from the liquid crystal display has a luminance Y, the liquid crystal image passed through the cholesteric liquid crystal layer has a luminance Z exceeding Y×

(1−

X).