Reflection light absorbing plate and display panel for use in a display ...

United States Patent

[19]

Hiroshi

US005875013A [ii] Patent Number: 5,875,013 [45] Date of Patent: Feb. 23, 1999

[54] REFLECTION LIGHT ABSORBING PLATE AND DISPLAY PANEL FOR USE IN A DISPLAY APPARATUS

[75] Inventor: Takahara Hiroshi, Neyagawa, Japan

[73] Assignee: Matsushita Electric Industrial Co.,Ltd., Kadoma, Japan

[21] Appl. No.: 504,648

[22] Filed: Jul. 20, 1995

[30] Foreign Application Priority Data

Jul. 20, 1994 [JP] Japan 6-167944

Mar. 6, 1995 [JP] Japan 7-045642

[51] Int. CI.6 G02E 1/1335; G02E 1/137

[52] U.S. CI 349/110; 349/66; 349/122

[58] Field of Search 349/57, 61, 10,

349/63, 86, 66, 112, 110, 122, 137; 359/601,

613, 614, 609

[56] References Cited

U.S. PATENT DOCUMENTS

4,005,929 2/1977 Adams et al 349/63

4,017,157 4/1977 Van Riet 349/159

4,349,817 9/1982 Hoffman et al 349/63

5,150,232 9/1992 Gunkima et al 349/86

5,181,130 1/1993 Hubby, Jr 349/63

5,245,449 9/1993 Ooi et al. .

5,260,815 11/1993 Takizawa 349/159

5,299,289 3/1994 Omae et al. .

5,353,133 10/1994 Bernkopf 349/86

5,521,726 5/1996 Zimmerman et al 349/159

5,631,750 3/1997 Minoura et al 349/110

5,737,050 4/1998 Takahara et al 349/122

5,760,849 6/1998 Omae et al 349/58

FOREIGN PATENT DOCUMENTS

572996 8/1993 European Pat. Off. .
3-94225 4/1991 Japan .
5-341269 12/1993 Japan .

Primary Examiner—-William L. Sikes
Assistant Examiner—Tai V. Duong

Attorney, Agent, or Firm—-Wenderoth, Lind & Ponack,
L.L.P.

[57] ABSTRACT

The reflected light absorbing plate 23 is divided into plural areas by light absorbing walls 20, and is adapted to satisly a pre-determined condition among the width ol one area d, thickness thereol t and the refraction index ol the absorbing plate n. The reflected light absorbing plate 23 is applied to the display panel 134 having a polymer dispersed liquid crystal layer as a light modulating layer 16 via a light coupling layer 14. The reflected light absorbing plate 23 and the light modulating layer 16 are spaced by a pre-determined distance taking MTF into consideration. While the light 17a diffused at a minute area A is reflected at the interface 21 with air, the light is absorbed by the light absorbing wall 20 and never returns to the light modulating layer 16.

15 Claims, 69 Drawing Sheets