Color/black-and-white switchable portable terminal and display unit

• US 20040140972A1
• Filed: 01/08/2004
• Published: 07/22/2004
• Est. Priority Date: 05/24/2000
• Status: Active Grant

• Current Assignee: Panasonic Liquid Crystal Display Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Hitachi Displays Limited (Japan Display Incorporated)
• Inventors: Hirota, Shouichi, Hiyama, Ikuo, Tsumura, Makoto, Oouchi, Takayuki
• Granted Patent: US 7,038,641 B2
• Time in Patent Office: Days
• US Class Current: 345/204
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0056 for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G09G 2300/023 Display panel composed of stacked panels
• CPC Class Codes: G09G 2300/0434 Flat panel display in which a field is applied parallel to the display plane
• CPC Class Codes: G09G 2300/0456 with a reflective area and a transmissive area combined in one pixel, such as in transflectance pixels
• CPC Class Codes: G09G 2300/046 with an emissive area and a light-modulating area combined in one pixel
• CPC Class Codes: G09G 2300/0809 Several active elements per pixel in active matrix panels
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2300/0852 being a dynamic memory with more than one capacitor
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2310/027 Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
• CPC Class Codes: G09G 2320/041 Temperature compensation
• CPC Class Codes: G09G 2320/062 Adjustment of illumination source parameters
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2330/02 Details of power systems and of start or stop of display operation
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2330/022 in absence of operation, e.g. no data being entered during a predetermined time
• CPC Class Codes: G09G 2340/0428 Gradation resolution change
• CPC Class Codes: G09G 2340/0435 Change or adaptation of the frame rate of the video stream
• CPC Class Codes: G09G 2340/14 : Solving problems related to the presentation of information to be displayed
• CPC Class Codes: G09G 2360/144 : the light being ambient light
• CPC Class Codes: G09G 3/20 : for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
• CPC Class Codes: G09G 3/2011 : by amplitude modulation
• CPC Class Codes: G09G 3/2014 : by modulation of the duration of a single pulse during which the logic level remains constant
• CPC Class Codes: G09G 3/3225 : using an active matrix
• CPC Class Codes: G09G 3/3233 : with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/3258 : with pixel circuitry controlling the voltage across the light-emitting element
• CPC Class Codes: G09G 3/3406 : Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3611 : Control of matrices with row and column drivers
• CPC Class Codes: G09G 3/3648 : using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: G09G 5/028 : Circuits for converting colour display signals into monochrome display signals
• CPC Class Codes: H04W 52/027 : by controlling a display operation or backlight unit
• CPC Class Codes: Y02D 30/70 : in wireless communication networks

Abstract

A display unit has a brightness equal to that in a conventional black-and-white reflection type and the power consumption is small at a standby time, and bright color display of high quality can be produced and power consumption is small at the time of use. An information device having this display unit, such as a portable phone, also is provided. The display unit has a color light emitting means, a reflecting mean of external light and a light polarizing state modulating means. The display unit has a driving method switching means for switching color light emitting display and reflection display by on/off control of the light emitting means and switching control of a driving method of a display element.

Claims

1. A display device comprising:

a display section for displaying an image corresponding to a received image signal; and

a light source for supplying light to the display section;

a display mode judging section for judging one of a color display mode and a monochromatic reflection display mode using external light as a display mode of the image displayed in the display section;

a signal generating section for generating a control signal and an image signal corresponding to the display mode of the display section in accordance with instructions of the display mode judging section;

a signal processing switching section for switching a signal processing path in accordance with the control signal from the signal generating section;

a signal processing section for processing the image signal in accordance with the switching of the signal processing path of the signal switching section; and

a light source control section for controlling an operation of the light source in accordance with instructions from the signal switching section.

2. A display device comprising:

a display section for displaying an image corresponding to a received image signal; and

a light source for supplying light to the display section;

a display mode judging section for judging one of a color display mode and a monochromatic display mode as a display mode of the image displayed in the display section;

signal generating section for generating an image signal corresponding to the display mode of the display section by instructions of the display mode judging section;

a signal processing switching section for switching a signal processing path by instructions from the display mode judging section;

a signal processing section for processing the image signal in accordance with the switching of the signal processing path of the signal switching section; and

a light source control section for controlling an operation of the light source in accordance with instructions from the signal switching section.