Transmitting type display device

• US 4,760,389 A
• Filed: 11/20/1986
• Issued: 07/26/1988
• Est. Priority Date: 11/27/1985
• Status: Expired due to Term

• Current Assignee: TPO Hong Kong Holding Limited (InnoLux Corporation)
• Original Assignee: Hosiden Electronics Co. Ltd. (Hosiden Corporation)
• Inventors: Yasui, Masaru, Ukai, Yasuhiro, Aoki, Shigeo
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US06/932,839
• Time in Patent Office: 614 Days
• Field of Search: 340/702, 340/78.4, 340/719, 340/793, 350/345
• US Class Current: 345/102
• CPC Class Codes: G02F 1/13318 Circuits comprising a photodetector
• CPC Class Codes: G02F 1/133604 with lamps
• CPC Class Codes: G02F 2201/58 Arrangements comprising a monitoring photodetector
• CPC Class Codes: G09G 2320/0633 by amplitude modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336

Abstract

A transmitting type display device is disclosed, which comprises a transmitting type display panel to provide a display on the front surface, a light source for producing light illuminating the back surface of the transmitting type display and a brightness controller for controlling the intensity of light from the light source. The device comprises an ambient light detector disposed near the transmitting type display panel for detecting the intensity of ambient light incident on the display surface of the transmitting type display panel, and the brightness controller for controlling the light source according to the detection output of the ambient light detector such that the intensity of light from the light source to the transmitting type display panel is increased with an increase of the detected light intensity.

Claims

1. A transmitting type display device comprising:

a transmitting type display panel mounted in a housing, said display panel closing an opening in said housing;

a light source disposed within said housing on the back side of said transmitting type display panel for producing light illuminating the back side of said transmitting type display panel;

an ambient light detector disposed near said transmitting type display panel for detecting the intensity of ambient light incident on the display surface of said transmitting type display panel, said ambient light detector being formed on a projecting portion of a transparent substrate of said transmitting type display panel, and a light-blocking layer being formed on said transparent substrate for shielding said ambient light detector from light from said light source; and

a brightness controller for controlling said light source according to the outside of said ambient light detector such that the intensity of light from said light source incident on said transmitting type display panel is increased with an increase in the detected ambient light intensity;

said transmitting type display panel being a liquid crystal display panel which includes first and second transparent substrates and a liquid crystal sealed therebetween, pixel electrodes and thin-film transistors for selectively driving said pixel electrodes being formed on the inner surface of said first transparent substrate, said first transparent substrate having said projecting portion projecting therefrom outwards of said second transparent substrate, and said ambient light detector being formed on the same surface of said first transparent substrate on which said thin-film transistors are formed.

2. The transmitting type display device according to claim 1, wherein said thin-film transistors each have source and drain electrodes formed on said first transparent substrate, a semiconductor layer of amorphous silicon formed to stride said source and drain electrodes, a gate insulating layer formed on said semiconductor layer and a gate electrode formed on said gate insulating layer, and said ambient light detector having a pair of comb-like electrodes formed in a mutually interlaced arrangement and of the same material as said source and drain electrodes on said first transparent substrate, an amorphous silicon layer of the same material as said semiconductor layer formed to extend over said comb-like electrodes, and a protective insulating layer of the same material as said gate insulating layer formed on said amorphous silicon layer.

3. The transmitting type display device according to claim 1, which further comprises a back light detector for detecting the intensity of light incident on the back surface of said transmitting type display panel, the output of said back light detector being fed to said brightness controller, whereby said light source is so controlled that the intensity of light incident from said light source on the back surface of said transmitting type display panel is reduced with increasing light intensity detected by said back light detector.

4. The transmitting type display device according to claim 3, wherein said back light detector is formed on said projecting portion of said first transparent substrate and a light-blocking layer is formed on said first transparent substrate for blocking ambient light incident on said back light detector from the front side of said display panel.

5. The transmitting type display device according to claim 4, which further comprises a subtractor means for producing the difference between the detection outputs of said ambient light detector and said back surface light detector, an adder means for producing the sum of the output of said subtractor means and the output of a variable reference brightness setter, and a light control means for controlling said light source according to the output of said adder means.

6. The transmitting type display device according to claim 3, wherein said back light detector is formed in the same configuration as said ambient light detector on the same surface of said first transparent substrate on which said thin-film transistors are formed on, and a second light-blocking layer is formed on that same surface for shielding said back light detector from ambient light.