Liquid crystal antidazzle mirror

• US 4,799,769 A
• Filed: 07/09/1986
• Issued: 01/24/1989
• Est. Priority Date: 07/09/1985
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Tokai RIKA Denki Seisakusho 1 AZA NODA OAZA Toyota Oguchi-Cho Niwa-Gun Aichi Japan, Toyota Jidosha Kabushiki Kaisha 1 Toyota-Cho Toyota-Shi Aichi-Ken Japan
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Kawahashi, Akira, Demura, Hiroshi, Hayashi, Kazumi, Kokubu, Sadao
• Primary Examiner(s): Miller, Stanley D.
• Assistant Examiner(s): Phan, Trong Q.
• Application Number:
  US06/883,881
• Time in Patent Office: 930 Days
• Field of Search: 350/331 R, 350/338, 350/342, 350/278, 350/279, 350/283, 350/332, 350/276 R, 307/597, 307/200 B, 361/92, 361/111
• US Class Current: 349/195
• CPC Class Codes: B60R 1/088 using a cell of electrically changeable optical characteristic, e.g. liquid-crystal or electrochromic mirrors

Abstract

A liquid crystal antidazzle mirror for turning OFF a power of a liquid crystal drive control circuit by a power switch provided between the liquid crystal drive control circuit and a power source comprising a capacitor of a predetermined capacity disposed between the power switch and the liquid crystal drive control circuit and connected in parallel between power lines to supply power from the capacitor to at least a mode memory circuit in the liquid crystal drive control circuit for a predetermined time determined by the discharging characteristic of the capacitor when the power switch is opened. Thus, the mirror can reset the set mode of the antidazzle mirror to the used mode immediately before a power switch is opened when the power switch is closed within a predetermined time after the power switch is opened.

Claims

1. An antidazzle mirror including a liquid crystal layer disposed in front of the mirror and a drive control circuit for controlling the operating mode of the liquid crystal, the drive control circuit comprising:

a drive circuit for controlling a voltage applied to the liquid crystal to change the light transmission factor of the layer between a high transmission dazzle mode and a low transmission antidazzle mode;

a mode memory circuit connected to the drive circuit for delivering a command signal for selectively placing the mirror in one of the dazzle and antidazzle modes; and

a mode switching circuit connected to the mode memory circuit, the mode switching circuit having a manually operable switch for changing the mode memory circuit from the one mode to the other mode, wherein

a capacitor is connected across power supply lines in parallel with a power source between a power switch and the mode memory circuit so as to be charged when the power switch is closed, the capacitor having a predetermined capacity sufficient to continue to supply power to the mode memory circuit for a predetermined time after the power switch is opened, so as to maintain for said predetermined time the mode memory circuit in the mode in effect at the time of opening the power switch.

2. A drive control circuit according to claim 1 wherein the mode memory circuit comprises a flip-flop.

3. A drive control circuit according to claim 2 wherein said mode switching circuit comprises means having an output terminal for delivering a pulse each time the manually operable switch is actuated, the output terminal of said pulse delivering means being connected to the flip-flop of the mode memory circuit.