Reflection-type display apparatus having antireflection films

• US 5,978,056 A
• Filed: 10/15/1996
• Issued: 11/02/1999
• Est. Priority Date: 10/15/1995
• Status: Expired due to Term

• Current Assignee: JVC Kenwood Corporation
• Original Assignee: Victor Company of Japan Limited (JVC Kenwood Corporation)
• Inventors: Honma, Akira, Shintani, Masaki, Shigeta, Masanobu, Kurogane, Hideo, Nishihata, Toshihiko
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): TON, MINH TOAN T
• Application Number:
  US08/730,241
• Time in Patent Office: 1,113 Days
• Field of Search: 349/44, 349/113, 349/137, 349/138, 349/111
• US Class Current: 349/137
• CPC Class Codes: G02F 1/133553 Reflecting elements associated to illuminating devices G02F1/133605
• CPC Class Codes: G02F 1/136277 formed on a semiconductor substrate, e.g. of silicon

Abstract

An active circuit element substrate is provided with a matrix array of active circuit elements. Each of the active circuit elements includes 1) a switching element, 2) a capacitor, 3) an electrically-conductive portion connecting the switching element and the capacitor, 4) an insulating layer covering the switching element, the capacitor, and the electrically-conductive portion, and 5) a reflective electrode layer connected to the electrically-conductive portion and extending on the insulating layer. The insulating layer has a surface flat so as to agree with a mirror finished surface. The reflective electrode layer extends on the surface of the insulating layer. A transparent common electrode film extends on a surface of a transparent substrate. An optical modulation layer is located between the reflective electrode layers on the active circuit element substrate and the common electrode film on the transparent substrate. A voltage difference is generated between each of the reflective electrode layers and the common electrode film in response to a signal applied to a control terminal of the related switching element, and light incident to the transparent substrate is modulated by the optical modulation layer in response to the voltage difference and is reflected by the related reflective electrode layer. A light shielding layer covers regions between the reflective electrode layers except portions occupied by metal areas of the active circuit elements as viewed along a direction of incidence of the light. The light shielding layer extends in the insulating layer.

Claims

1. A reflection-type display apparatus comprising:

an active circuit element substrate;

a matrix array of active circuit elements provided on the active circuit element substrate and each corresponding to one pixel, wherein each of the active circuit elements includes

     1) a switching element,

     2) a capacitor,

     3) an electrically-conductive portion connecting the switching element and the capacitor,

     4) an insulating layer covering the switching element, the capacitor, and the electrically-conductive portion, and

     5) a reflective electrode layer connected to the electrically-conductive portion and extending on the insulating layer, and wherein the reflective electrode layer extends on the surface of the insulating layer;

a transparent substrate;

a transparent common electrode film extending on a surface of the transparent substrate;

an optical modulation layer located between the reflective electrode layers on the active circuit element substrate and the common electrode film on the transparent substrate;

wherein a voltage difference is generated between each of the reflective electrode layers and the common electrode film in response to a signal applied to a control terminal of the related switching element, and light incident to the transparent substrate is modulated by the optical modulation layer in response to the voltage difference and is reflected by the related reflective electrode layer;

a light shielding layer covering regions between the reflective electrode layers except portions occupied by electrically conductive portions of the active circuit elements as viewed along a direction of incidence of the light for shielding said active circuit element substrate from direct light exposure, the light shielding layer extending on the insulating layer; and

antireflection films extending on surfaces of the reflective electrode layers which face the light shielding layer, and an antireflection film extending on a surface of the light shielding layer which faces the reflective electrode layers for preventing multiple reflection of light between the surfaces of the reflective electrode layers and the surface of the light shielding layer and blocking the light indirectly advancing toward said active circuit element substrate to protect said active circuit element substrate from indirect light exposure.

2. A reflection-type display apparatus as recited in claim 1, wherein each of the reflective electrode layers is made of a metal selected from the group consisting of aluminum, aluminum-based material containing silicon, and aluminum-based material containing copper.

3. A reflection-type display apparatus as recited in claim 1, further comprising a reflection enhancement layer extending on the reflective electrode layers, the reflection enhancement layer including a laminate of dielectric films, the reflection enhancement layer including an alternation of silicon oxide films and titanium oxide films, the reflection enhancement layer having a thickness of about 5,000 Å

or less.

4. A reflection-type display apparatus as recited in claim 1, further comprising insulating portions filling the regions between the reflective electrode layers, the insulating portions having surfaces which are flat so as to be in agreement with mirror finished surfaces.

5. A reflection-type display apparatus as recited in claim 1, wherein the switching elements include transistors respectively, and further comprising separating regions located between the active circuit elements, the separating regions having a conductivity type equal to a conductivity type of output electrodes of the transistors.

6. A reflection-type display apparatus as recited in claim 1, wherein the active circuit element substrate includes a semiconductor substrate, and the switching elements include transistors on the semiconductor substrate respectively, the semiconductor substrate having wells separate from each other, the wells having a conductivity type opposite to a conductivity type of output electrodes of the transistors, the transistors being provided in the wells respectively.

7. A reflection-type display apparatus as recited in claim 1, wherein the light shielding layer includes a plurality of separate layers.

8. A reflection-type display apparatus as recited in claim 1, wherein the light shielding layer includes a film of aluminum which has a thickness of 3,000 Å

, and the antireflection film on the surface of the light shielding layer includes a film of titanium nitride which has a thickness of 1,000 Å

, and the antireflection films on the surfaces of the reflective electrode layers include films of titanium nitride which have a thickness of 500 Å

.

9. A reflection-type display apparatus comprising:

a semiconductor substrate;

an insulating layer provided on the semiconductor substrate;

first and second reflective electrode layers provided on the insulating layer and being separate from each other;

a light shielding layer provided on the semiconductor substrate and covering a region between the first and second reflective electrode layers to prevent light from directly entering the semiconductor substrate via the region between the first and second reflective electrode layers; and

an antireflection film provided on a surface of the light shielding layer which faces the first and second reflective electrode layers, and antireflection films provided on surfaces of the first and second reflective electrode layers which face the light shielding layer for preventing multiple reflection of the light between the surfaces of the first and second reflective electrode layers and the surface of the light shielding layer and blocking the light indirectly advancing toward the semiconductor substrate to protect the semiconductor substrate from indirect light exposure.

10. A reflection-type display apparatus as recited in claim 9, further comprising a reflection enhancement layer extending on the first and second reflective electrode layers, the reflection enhancement layer including a laminate of dielectric films the reflection enhancement layer including an alternation of silicon oxide films and titanium oxide films, the reflection enhancement layer having a thickness of about 5,000 Å

or less.

11. A reflection-type display apparatus as recited in claim 9, further comprising an insulating portion provided on the semiconductor substrate and being located at the region between the first and second reflective electrode layers, the insulating portion having a mirror finished surface.

12. A reflection-type display apparatus as recited in claim 9, further comprising a first transistor provided on the semiconductor substrate and being connected to the first reflective electrode layer, the first transistor forming a first cell in conjunction with the first reflective electrode layer, a second transistor provided on the semiconductor substrate and being connected to the second reflective electrode layer, the second transistor forming a second cell in conjunction with the second reflective electrode layer, and a separating region provided in the semiconductor substrate and being located between the first and second cells, the separating region having a conductivity type equal to a conductivity type of output electrodes of the first and second transistors.

13. A reflection type display apparatus as recited in claim 9, further comprising transistors provided on the semiconductor substrate and being connected to the first and second reflective electrode layers respectively, the semiconductor substrate having wells separate from each other, the wells having a conductivity type opposite to a conductivity type of output electrodes of the transistors, the transistors being provided in the wells respectively, the wells being subjected to a ground potential.

14. A reflection-type display apparatus as recited in claim 13, wherein the sells are of a P type, and the transistors provided in the wells comprise N-channel MOS FET'"'"'s.

15. A reflection-type display apparatus as recited in claim 9, wherein the light shielding layer includes a film of aluminum which has a thickness of 3,000 Å

, and the antireflection film on the surface of the light shielding layer includes a film of titanium nitride which has a thickness of 1,000 Å

, and the antireflection films on the surfaces of the reflective electrode layers include films of titanium nitride which have a thickness of 500 Å

.