Semi-transmissive liquid crystal display device and portable terminal device

• US 9,091,872 B2
• Filed: 08/07/2013
• Issued: 07/28/2015
• Est. Priority Date: 12/22/2005
• Status: Active Grant

• Current Assignee: NLT Technologies, Ltd. (Tianma Microelectronics Company Limited)
• Original Assignee: NLT Technologies, Ltd. (Tianma Microelectronics Company Limited)
• Inventors: Matsushima, Jin, Okumura, Hiroshi, Sumiyoshi, Ken
• Primary Examiner(s): Ghebretinsae, Temesgh
• Assistant Examiner(s): Ketema, Benyam
• Application Number:
  US13/960,896
• Publication Number:
  US 20140104520A1
• Time in Patent Office: 720 Days
• Field of Search: 345/87, 345/102, 349 61- 66
• US Class Current: 1/1
• CPC Class Codes: G02F 1/1323 Arrangements for providing a switchable viewing angle
• CPC Class Codes: G09G 2310/0297 Special arrangements with multiplexing or demultiplexing of display data in the drivers for data electrodes, in a pre-processing circuitry delivering display data to said drivers or in the matrix panel, e.g. multiplexing plural data signals to one D/A converter or demultiplexing the D/A converter output to multiple columns
• CPC Class Codes: G09G 2320/0209 Crosstalk reduction, i.e. to reduce direct or indirect influences of signals directed to a certain pixel of the displayed image on other pixels of said image, inclusive of influences affecting pixels in different frames or fields or sub-images which constitute a same image, e.g. left and right images of a stereoscopic display
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• CPC Class Codes: G09G 3/3688 suitable for active matrices only

Abstract

A liquid crystal display accommodates a reflective portion with a concavo-convex reflecting pixel electrode for reflecting incident light from the display face side, and a transmissive portion with a transmissive pixel electrode for transmitting light output from the backlight. In a wide viewing angle region, luminance of the reflective portion is greater than the transmissive portion. In other angle regions, luminance of the transmissive portion is greater than the reflective portion. In a wide viewing field mode, the reflective portion and transmissive portion both perform normal display. In the narrow viewing field mode, the transmissive portion performs normal display, while the reflective portion performs cancelling data display, thereby rendering unviewable the display content of the transmissive portion from beyond a certain viewing angle. Thus, a semi-transmissive liquid crystal display device and a portable terminal device is switchable between a narrow viewing field mode and a wide viewing field mode.

Claims

1. A semi-transmissive liquid crystal display device comprising:

a liquid crystal panel provided with a liquid crystal layer between two substrates having electrodes formed thereon;

a backlight for outputting light to the liquid crystal panel; and

a controller for controlling a voltage applied to the liquid crystal layer;

wherein

each of pixels of the liquid crystal panel individually has a reflective portion for reflecting and displaying light incident from the display screen side, and a transmissive portion for transmitting and displaying light that is output by said backlight;

a normal display by the reflective portion has wide viewing angle characteristics, solely viewable in a wide viewing area, and a normal display the transmissive portion has narrow viewing angle characteristics, solely viewable only in a narrow viewing area, and

the controller controls, independently for said reflective portion and the transmissive portion, the voltage applied to the liquid crystal layer, and switches a viewing angle between a wide viewing field mode and a narrow viewing field mode by performing control so that, in the wide viewing field mode, the reflective portion performs the normal display while the transmissive portion performs the normal display, thereby allowing the normal display by the reflective portion to be viewable in the wide viewing area, whereas in the narrow viewing field mode the reflective portion performs a dark display while the transmissive portion performs the normal display thereby allowing the normal display by the transmissive portion to be viewable only in the narrow viewing area,

wherein the reflective portions of part of the pixels perform normal display instead of dark display in the narrow viewing field mode, so that an image pattern is displayed and wherein the display of the image pattern in the narrow viewing field mode varies spatially, temporally, or spatiotemporally.

3. A portable terminal device comprising the semi-transmissive liquid crystal display device according to claim 1.

2. A semi-transmissive liquid crystal display device comprising:

a liquid crystal panel provided with a liquid crystal layer between two substrates having electrodes formed thereon;

a backlight for outputting light to the liquid crystal panel; and

a controller for controlling a voltage applied to the liquid crystal layer;

wherein

each of pixels of the liquid crystal panel individually has a reflective portion for reflecting and displaying light incident from the display screen side, and a transmissive portion for transmitting and displaying light that is output by the backlight;

a normal display by the reflective portion has narrow viewing angle characteristics, solely viewable only in a narrow viewing area, and the transmissive portion has wide viewing angle characteristics, solely viewable in a wide viewing area, and

the controller controls, independently for the reflective portion and the transmissive portion, the voltage applied to the liquid crystal layer, and switches a viewing angle between a wide viewing field mode and a narrow viewing field mode by performing control so that in the wide viewing field mode the reflective portion performs the normal display, thereby allowing the normal display by the transmissive portion to be viewable in the wide viewing area, while said transmissive portion performs normal display, whereas in the narrow viewing field mode the reflective portion performs the normal display while said transmissive portion performs a dark display, thereby allowing the normal display by the reflective portion to be viewable only in the narrow viewing area,

wherein the transmissive portions of part of the pixels perform normal display instead of dark display in the narrow viewing field mode, so that an image pattern is displayed and wherein the display of the image pattern in the narrow viewing field mode varies spatially, temporally, or spatiotemporally.

4. A portable terminal device comprising the semi-transmissive liquid crystal display device according to claim 2.