Liquid crystal dazzle-free reflection mirror

• US 4,671,617 A
• Filed: 08/06/1985
• Issued: 06/09/1987
• Est. Priority Date: 08/08/1984
• Status: Expired due to Fees

• Current Assignee: Nippondenso Company Limited 1-1 Showa-Cho Kariya-Shi Aichi Japan
• Original Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Inventors: Hara, Kunihiko
• Primary Examiner(s): Corbin, John K.
• Assistant Examiner(s): Lewis, David
• Application Number:
  US06/762,837
• Time in Patent Office: 672 Days
• Field of Search: 350/331 R, 350/332, 350/338, 350/342, 350/335, 350/349, 350/357, 350/278, 350/283
• 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
• CPC Class Codes: G02F 1/13318 Circuits comprising a photodetector
• CPC Class Codes: G02F 1/133553 Reflecting elements associated to illuminating devices G02F1/133605
• CPC Class Codes: G02F 1/13475 in which at least one liquid crystal cell or layer is doped with a pleochroic dye, e.g. GH-LC cell G02F1/13476 takes precedence
• CPC Class Codes: G02F 1/13476 in which at least one liquid crystal cell or layer assumes a scattering state
• CPC Class Codes: G02F 1/13725 based on guest-host interaction G02F1/13762, G02F1/13737, take precedence
• CPC Class Codes: G02F 1/1375 using dynamic scattering
• CPC Class Codes: G02F 2203/02 reflective

Abstract

A liquid crystal type dazzle-free reflection mirror has a scattering type liquid crystal cell such as DSM liquid crystal switching the orientation of the liquid crystal molecular axis thereof between a random orientation and a regular orientation depending on an electric field applied thereto. At least one coloring filter cell such as guest-host liquid crystal provided at a front side of the scattering type liquid crystal cell to which light is incident and switching, depending on an electric field applied thereto, between two light transmitting states in which white light is transmitted and specific color light is transmitted more, respectively. A reflection mirror layer reflecting the light transmitted through the scattering type liquid crystal cell and the coloring filter cell is provided behind the scattering type liquid crystal cell so that a reflection image may be provided on the mirror surface.

Claims

1. A liquid crystal type dazzle-free reflection mirror comprising:

a scattering liquid crystal cell switching, depending on an electric field applied thereto, the orientation of liquid crystal molecular axis thereof between a random orientation and a regular orientation;

a coloring filter cell provided at a front side of said scattering liquid crystal cell to which light is incident and switching, depending on an electric field applied thereto, between two light transmitting states in one and the other of which the light transmitted therethrough is colored and decolored;

a reflection mirror layer reflecting the light transmitted from said coloring filter cell through said scattering liquid crystal cell; and

control means responsive to a light incident thereto for controlling the electric fields applied to said scattering liquid crystal cell and said coloring filter cell so that said scattering liquid crystal cell provides the random orientation and the coloring filter cell colors the light when the incident light is intensive.

2. A dazzle-free reflection mirror according to claim 1, wherein said coloring filter cell comprises a guest-host liquid crystal in which liquid crystal molecules and pigment molecules are mixed and oriented so that the light transmitted therethrough is colored in response to the presence of the electric field applied thereto.

3. A dazzle-free reflection mirror according to claim 1, wherein said scattering liquid crystal cell comprises a dynamic scattering mode liquid crystal the molecules of which are oriented regularly and at random in response to the absence and presence of the electric field applied thereto, respectively.

4. A dazzle-free reflection mirror according to claim 3, wherein said coloring filter cell comprises a guest-host liquid crystal the molecules of which are oriented vertically and horizontally relative to electrodes thereof in response to the absence and presence of the electric field applied thereto.

5. A dazzle-free reflection mirror according to claim 1, wherein said coloring filter cell is inclined relative to the scattering liquid crystal cell.

6. A dazzle-free reflection mirror according to claim 1, wherein said scattering liquid crystal cell comprises a liquid crystal the molecules of which are twisted in the regular orientation.

7. A dazzle-free reflection mirror according to claim 6, further comprising a coloring filter cell provided between said scattering liquid crystal cell and said reflection mirror layer and switching, depending on an electric field applied thereto, between two light transmitting states in one and the other of which the light transmitted therethrough is colored and decolored.

8. A dazzle-free reflection mirror according to claim 7, wherein each of said coloring filter cells comprise guest-host liquid crystals the molecules of which are oriented horizontally relative to respective electrodes thereof but arranged at a right angle to each other in the absence of the electric field applied thereto.

9. A dazzle-free reflection mirror according to claim 1, wherein said coloring filter cell comprises an electrochromic element.