Color liquid crystal display device having a semitransparent layer on the inner surface of one of the substrates

• US 5,753,937 A
• Filed: 05/31/1995
• Issued: 05/19/1998
• Est. Priority Date: 05/31/1994
• Status: Expired due to Term

• Current Assignee: Casio Computer Company Limited
• Original Assignee: Casio Computer Company Limited
• Inventors: Shimomaki, Shinichi, Yoshida, Tetsushi
• Primary Examiner(s): Thomas, Tom
• Assistant Examiner(s): Abraham, Fetsum
• Application Number:
  US08/455,898
• Time in Patent Office: 1,084 Days
• Field of Search: 359/37, 359/60, 359/63, 359/70, 359/73, 359/75, 359/93, 257/59, 257/72, 349/67, 349/80, 349/96
• US Class Current: 257/59
• CPC Class Codes: G02F 1/133555 Transflectors
• CPC Class Codes: G02F 1/13363 Birefringent elements, e.g. for optical compensation
• CPC Class Codes: G02F 1/1396 the liquid crystal being selectively controlled between a twisted state and a non-twisted state, e.g. TN-LC cell G02F1/141 takes precedence
• CPC Class Codes: G02F 2203/02 reflective
• CPC Class Codes: G02F 2203/34 Colour display without the use of colour mosaic filters

Abstract

A color liquid crystal display device includes a front substrate having a surface on which a plurality of pixel electrodes are arranged in the form of a matrix, and two-terminal nonlinear resistor elements are arranged to correspond to the pixel electrodes. An aligning film covers the pixel electrodes and the nonlinear resistor elements. A rear substrate opposes the front substrate and has an inner surface on which counter electrodes are arranged to oppose the pixel electrodes, for forming a plurality of pixels. An aligning film covers the pixel and counter electrodes. A liquid crystal layer is sandwiched between the front and rear substrates and has an initial aligned state in which liquid crystal molecules are aligned in a predetermined direction by the aligning films. A polarizing member is arranged on an outer side of the front substrate such that a polarization axis of the polarizing member crosses an aligning direction of liquid crystal molecules adjacent to the aligning film on the front substrate side at an angle other than a right angle. A reflecting member is arranged on the rear substrate side. The two-terminal nonlinear resistor elements have one terminal connected to the pixel electrode, and another terminal receiving a signal voltage.

Claims

1. A color liquid crystal display device comprising:

a first substrate having an inner surface on which a plurality of pixel electrodes arranged in the form of a matrix, to said pixel electrodes and each having one terminal connected to a corresponding one of said pixel electrodes and another terminal applied with a signal voltage, and a first aligning film covering said pixel electrodes and said nonlinear resistor elements are arranged;

a second substrate arranged to oppose said first substrate and having an inner surface on which counter electrodes, arranged to oppose said plurality of pixel electrodes, for forming a plurality of pixels in areas opposing said pixel electrodes and a second aligning film covering said pixel and counter electrodes are arranged;

a liquid crystal layer sandwiched between said first and second substrates and having an initial aligned state in which liquid crystal molecules are aligned in a predetermined direction by said first and second aligning films;

a first polarizing member arranged on an outer side of at least a light incident substrate of said first and second substrates such that a polarization axis of said first polarizing member crosses an aligning direction of liquid crystal molecules adjacent to said first or second aligning film on the substrate side at an angle other than a right angle;

a semitransparent reflecting member, arranged on a side of the inner surface of one of said first and second substrates which opposes said light incident substrate, for reflecting part of light incident from said first polarizing member and transmitted through said liquid crystal layer and causing another part of the incident light to transmit through said semitransparent reflecting member; and

a second polarizing member arranged on an outer side of said semitransparent reflecting member;

and wherein said first and second polarizing members are arranged on an outer side of said first and second substrates so that light transmitted through the polarizing members becomes light colored with a color corresponding to a ratio of light amounts of wavelength light components by controlling birefringence effects of said liquid crystal layer corresponding to a voltage applied between said pixel electrodes and said counter electrodes.

2. A device according to claim 1, wherein:

said plurality of pixel electrodes or said plurality of counter electrodes have metal films in each of which a large number of small light-transmitting holes are formed, and have a function of said semitransparent reflecting member, and

said polarizing member arranged on an exit side comprises a light-scattering film on a surface thereof, said light-scattering film serving to scatter light transmitted therethrough.

3. A device according to claim 1, wherein:

said plurality of pixel electrodes of said first substrate have metal films, in each of which a large number of small light-transmitting holes are formed, and have a function of said semitransparent reflecting member, and

said counter electrodes of said second substrate have transparent conductive films and form a first optical path in which light incident from said second substrate is transmitted through said liquid crystal layer, reflected by said pixel electrodes to return, and transmitted through said liquid crystal layer again to emerge from said second substrate and form a second optical path in which light incident from said first substrate is transmitted through said pixel electrodes and said liquid crystal layer to emerge from said second substrate.

4. A device according to claim 1, wherein:

said plurality of counter electrodes of said second substrate have metal films, in each of which a large number of small light-transmitting holes are formed, and have a function of said semitransparent reflecting member, and

said pixel electrodes of said first substrate have transparent conductive films and form a first optical path in which light incident from said first substrate is transmitted through said liquid crystal layer, reflected by said counter electrodes to return, and transmitted through said liquid crystal layer again to emerge from said first substrate and form a second optical path in which light incident from said second substrate is transmitted through said counter electrodes and said liquid crystal layer to emerge from said first substrate.

5. A device according to claim 1, further comprising light-shielding members, arranged on a side of the inner surface of one of said first and second substrates, for preventing leakage of light between said plurality of pixels.

6. A device according to claim 1, further comprising at least one retardation plate arranged between said polarizing member arranged on an exit side and the substrate, adjacent to said exit-side polarizing member, of said first and second substrates such that an optical axis of said at least one retardation plate crosses a direction of an optical axis of said exit-side polarizing member at an angle other than a right angle.

7. A color liquid crystal display device comprising:

a first substrate having an inner surface on which a plurality of pixel electrodes arranged in the form of a matrix, two-terminal nonlinear resistor elements arranged to correspond to said pixel electrodes and each having one terminal connected to a corresponding one of said pixel electrodes and another terminal applied with a signal voltage, and a first aligning film covering said pixel electrodes and said nonlinear resistor elements are arranged;

a second substrate arranged to oppose said first substrate and having an inner surface on which counter electrodes, arranged to oppose said plurality of pixel electrodes, for forming a plurality of pixels in areas opposing said pixel electrodes and a second aligning film covering said pixel and counter electrodes are arranged;

a liquid crystal layer sandwiched between said first and second substrates and having an initial aligned state in which liquid crystal molecules are aligned in a predetermined direction by said first and second aligning films;

a first polarizing member arranged on an outer side of at least a light incident substrate of said first and second substrates such that a polarization axis of said first polarizing member crosses an aligning direction of liquid crystal molecules adjacent to said first or second aligning film on the substrate side at an angle other than a right angle;

a semitransparent reflecting member, arranged on the substrate side opposing said light incident substrate of said first and second substrates, for reflecting part of light incident from said first polarizing member and transmitted through said liquid crystal layer and causing another part of the incident light to transmit through said semitransparent reflecting member; and

a second polarizing member arranged on an outer side of said semitransparent reflecting member;

and wherein;

said plurality of pixel electrodes or said plurality of counter electrodes have metal films in each of which a large number of small light-transmitting holes are formed, and have a function of said semitransparent reflecting member, and

said polarizing member arranged on an exit side comprises a light-scattering film on a surface thereof, said light-scattering film serving to scatter light transmitted therethrough.

8. A color liquid crystal display device comprising:

a first substrate having an inner surface on which a plurality of pixel electrodes arranged in the form of a matrix, two-terminal nonlinear resistor elements arranged to correspond to said pixel electrodes and each having one terminal connected to a corresponding one of said pixel electrodes and another terminal applied with a signal voltage, and a first aligning film covering said pixel electrodes and said nonlinear resistor elements are arranged;

a second substrate arranged to oppose said first substrate and having an inner surface on which counter electrodes, arranged to oppose said plurality of pixel electrodes, for forming a plurality of pixels in areas opposing said pixel electrodes and a second aligning film covering said pixel and counter electrodes are arranged;

a liquid crystal layer sandwiched between said first and second substrates and having an initial aligned state in which liquid crystal molecules are aligned in a predetermined direction by said first and second aligning films;

a first polarizing member arranged on an outer side of at least a light incident substrate of said first and second substrates such that a polarization axis of said first polarizing member crosses an aligning direction of liquid crystal molecules adjacent to said first or second aligning film on the substrate side at an angle other than a right angle;

a semitransparent reflecting member, arranged on the substrate side opposing said light incident substrate of said first and second substrates, for reflecting part of light incident from said first polarizing member and transmitted through said liquid crystal layer and causing another part of the incident light to transmit through said semitransparent reflecting member; and

a second polarizing member arranged on an outer side of said semitransparent reflecting member;

and wherein;

said plurality of pixel electrodes of said first substrate have metal films, in each of which a large number of small light-transmitting holes are formed, and have a function of said semitransparent reflecting member, and

said counter electrodes of said second substrate have transparent conductive films and form a first optical path in which light incident from said second substrate is transmitted through said liquid crystal layer, reflected by said pixel electrodes to return, and transmitted through said liquid crystal layer again to emerge from said second substrate and form a second optical path in which light incident from said first substrate is transmitted through said pixel electrodes and said liquid crystal layer to emerge from said second substrate.

9. A color liquid crystal display device comprising:

a first substrate having an inner surface on which a plurality of pixel electrodes arranged in the form of a matrix, two-terminal nonlinear resistor elements arranged to correspond to said pixel electrodes and each having one terminal connected to a corresponding one of said pixel electrodes and another terminal applied with a signal voltage, and a first aligning film covering said pixel electrodes and said nonlinear resistor elements are arranged;

a second substrate arranged to oppose said first substrate and having an inner surface on which counter electrodes, arranged to oppose said plurality of pixel electrodes, for forming a plurality of pixels in areas opposing said pixel electrodes and a second aligning film covering said pixel and counter electrodes are arranged;

a liquid crystal layer sandwiched between said first and second substrates and having an initial aligned state in which liquid crystal molecules are aligned in a predetermined direction by said first and second aligning films;

a first polarizing member arranged on an outer side of at least a light incident substrate of said first and second substrates such that a polarization axis of said first polarizing member crosses an aligning direction of liquid crystal molecules adjacent to said first or second aligning film on the substrate side at an angle other than a right angle;

a semitransparent reflecting member, arranged on the substrate side opposing said light incident substrate of said first and second substrates, for reflecting part of light incident from said first polarizing member and transmitted through said liquid crystal layer and causing another part of the incident light to transmit through said semitransparent reflecting member; and

a second polarizing member arranged on an outer side of said semitransparent reflecting member;

and wherein;

said plurality of counter electrodes of said second substrate have metal films, in each of which a large number of small light-transmitting holes are formed, and have a function of said semitransparent reflecting member, and

said pixel electrodes of said first substrate have transparent conductive films and form a first optical path in which light incident from said first substrate is transmitted through said liquid crystal layer, reflected by said counter electrodes to return, and transmitted through said liquid crystal layer again to emerge from said first substrate and form a second optical path in which light incident from said second substrate is transmitted through said counter electrodes and said liquid crystal layer to emerge from said first substrate.