US5341231A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Liquid crystal display device with edge lit lightguide reflecting light to back reflector by total internal reflection
Assignee: Sharp Corp
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Filing: 1992-12-03
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Granted: 1994-08-23
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Expires: 2012-12-03
Abstract
Abstract A reflective type liquid crystal display device excelling in uniformity and capable of making a bright display is presented. At the front side of the liquid crystal display element, that is, at the observer side, a light guide plate is disposed, and a pair of lamps are disposed at the outer side of the confronting side surfaces of the light guide plate. Collimators for limiting the incident angle θ to the upper surface of the light from the lamps are disposed between the light guide plate and lamps. That is, by the collimators, the incident angle θ to the upper surface is defined so that the incident light may be totally reflected, and that the reflected light may not be totally reflected by the lower surface 61b. As a result, the light from the lamps will not reach the observer directly, and a uniform illumination of the liquid crystal display element may be realized. Besides, at the observer side of the liquid crystal display element, a light guide plate forming protrusions is disposed, and a pair of lamps are disposed at the outer side of the confronting side surfaces of the light guide plate. Furthermore, between the light guide plate and lamps, collimators for limiting the incident angle θ of the light from the lamps into the upper surface are disposed. Accordingly, the light from the lamps does not reach the observer directly, and the light entering the protrusions formed on the light guide plate is emitted to the liquid crystal display element side. Thus, a uniform illumination into the liquid crystal display element is realized.
Inventors
- 👤 Yoshitaka Yamamoto
- 👤 Yutaka Ishii
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 12:06
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/0001; G02B6/0011; G02B6/0013; G02B6/0023; G02B6/003; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1335; G02F1/1336; G02F1/133615; G02F1/133616; G09; G09F; G09F13/00; G09F13/18; G09F2013/1804; G09F2013/1822; G09F2013/1827; G09F2013/1831
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
189 words
A liquid crystal display device comprising: a liquid crystal display element composed of a transparent substrate, a counter substrate disposed oppositely to the transparent substrate and possessing reflecting means for reflecting the incident light entering from the transparent substrate side, and a liquid crystal layer interposed therebetween, a light guide plate disposed at the transparent substrate side of the liquid crystal display element, a light source disposed at the edge of the light guide plate, and a collimator disposed between the light guide plate and the light source for controlling the light from the light source, wherein the condition of n1<n·sin θ<n2 (1) is satisfied supposing the refractive index of the light guide plate is n, the refractive index of a substance positioned at the side of the light guide plate opposite the liquid crystal display element is n1, the refractive index of a substance positioned at the liquid crystal display element side of the light guide plate is n2, and the incident angle of the light source light transmitted through the collimator to the side of the light guide plate opposite the liquid crystal display element is θ.
Claim 2
Dependent Claim
189 words
A liquid crystal display device comprising: a liquid crystal display element composed of a transparent substrate, a counter substrate disposed oppositely to the transparent substrate and possessing reflecting means for reflecting the incident light entering from the transparent substrate side, and a liquid crystal layer interposed therebetween, a light guide plate disposed at the transparent substrate side of the liquid crystal display element, a light source disposed at the edge of the light guide plate, and a collimator disposed between the light guide plate and the light source for controlling the light from the light source, wherein the condition of n1<n·sin θ<n2 (1) is satisfied supposing the refractive index of the light guide plate is n, the refractive index of a substance positioned at the side of the light guide plate opposite the liquid crystal display element is n1, the refractive index of a substance positioned at the liquid crystal display element side of the light guide plate is n2, and the incident angle of the light source light transmitted through the collimator to the side of the light guide plate opposite the liquid crystal display element is θ.
Claim 3
Dependent Claim
164 words
A liquid crystal display device comprising: a liquid crystal display element composed of a transparent substrate, a counter substrate disposed oppositely to the transparent substrate and possessing reflecting means for reflecting the incident light entering from the transparent substrate side, and a liquid crystal layer interposed therebetween, a light guide plate disposed at the transparent substrate side of the liquid crystal display element, and a light source disposed at the edge of the light guide plate, wherein plural protrusions are formed on the surface of the light guide plate at the liquid crystal display element side, and the condition of n1<n·sin θ (2) is satisfied, supposing the refractive index of the light guide plate is n, the refractive index of a substance positioned at the side of the light guide plate opposite the liquid crystal display element is n1, and the incident angle of the light source light to the side of the light guide plate opposite the liquid crystal display element is θ.
Claim 4
Dependent Claim
164 words
A liquid crystal display device comprising: a liquid crystal display element composed of a transparent substrate, a counter substrate disposed oppositely to the transparent substrate and possessing reflecting means for reflecting the incident light entering from the transparent substrate side, and a liquid crystal layer interposed therebetween, a light guide plate disposed at the transparent substrate side of the liquid crystal display element, and a light source disposed at the edge of the light guide plate, wherein plural protrusions are formed on the surface of the light guide plate at the liquid crystal display element side, and the condition of n1<n·sin θ (2) is satisfied, supposing the refractive index of the light guide plate is n, the refractive index of a substance positioned at the side of the light guide plate opposite the liquid crystal display element is n1, and the incident angle of the light source light to the side of the light guide plate opposite the liquid crystal display element is θ.
Claim 5
Dependent Claim
41 words
A liquid crystal display device as claimed in claim 1 or 2, wherein the reflecting means has its reflection surface formed in a smooth undulated surface, and is disposed on the surface of the counter substrate opposite the liquid crystal layer.
Claim 6
Dependent Claim
44 words
A liquid crystal display device as claimed in claim 1 or 2, wherein the reflecting means has its reflection surface formed in a smooth undulated surface, and is disposed on the surface of the counter substrate on the side of the liquid crystal layer.
Claim 7
Dependent Claim
26 words
A liquid crystal display device as claimed in claim 1 or 2, wherein one polarizer is disposed at the viewer side of the light guide plate.
Claim 8
Dependent Claim
31 words
A liquid crystal display device as claimed in claim 5, wherein an air layer with a refractive index n1 (satisfying n1<n·sin θ) is interposed between the polarizer and light guide plate.
Claim 9
Dependent Claim
44 words
A liquid crystal display device as claimed in claim 5, wherein the surface of the viewer side of the light guide plate is coated with a material with a refractive index n1 (satisfying n1<n·sin θ), and the polarizer is directly disposed on its surface.
Claim 10
Dependent Claim
35 words
A liquid crystal display device as claimed in claim 5, wherein the polarizer is made of a material with a refractive index n1 (satisfying n1<n·sin θ) and is directly disposed on the light guide plate.
Claim 11
Dependent Claim
44 words
A liquid crystal display device as claimed in claim 1 or 2, wherein two polarizers are disposed, one polarizer at the viewer side of the light guide plate, and the other between the reflecting means located outside the counter substrate and the counter substrate.
Claim 12
Dependent Claim
33 words
A liquid crystal display device as claimed in claim 9, wherein an air layer with a refractive index n1 (satisfying n1<n·sin θ) is interposed between the one polarizer and the light guide plate.
Claim 13
Dependent Claim
45 words
A liquid crystal display device as claimed in claim 9, wherein the surface of the viewer side of the light guide plate is coated with a material with a refractive index n1 (satisfying n1<n·sin θ), and the one polarizer is directly disposed on its surface.
Claim 14
Dependent Claim
36 words
A liquid crystal display device as claimed in claim 9, wherein the one polarizer is made of a material with a refractive index n1 (satisfying n1<n·sin θ) and is directly disposed on the light guide plate.
Claim 15
Dependent Claim
26 words
A liquid crystal display device as claimed in claim 1 or 2, wherein a diffusion plate is disposed at the viewer side of the reflecting means.
Claim 16
Dependent Claim
40 words
A liquid crystal display device as claimed in claim 1 or 2, wherein a reflector for preventing light leak from the light guide plate is disposed at the edge of the light guide plate not provided with the light source.
Claim 17
Dependent Claim
29 words
A liquid crystal display device as claimed in claim 1 or 2, wherein the light source is lit when the surrounding light alone provides an insufficient quantity of light.
Claim 18
Dependent Claim
18 words
A liquid crystal display device as claimed in claim 2, wherein the protrusions are in a conical form.
Claim 19
Dependent Claim
18 words
A liquid crystal display device as claimed in claim 2, wherein the protrusions are in a pyramidal form.
Claim 20
Dependent Claim
19 words
A liquid crystal display device as claimed in claim 2, wherein the protrusions are in a truncated conical form.
Claim 21
Dependent Claim
19 words
A liquid crystal display device as claimed in claim 2, wherein the protrusions are in a truncated pyramidal form.
Claim 22
Dependent Claim
20 words
A liquid crystal display device as claimed in claim 2, wherein the sectional shape of the protrusions is nearly semicircular.
Claim 23
Dependent Claim
19 words
A liquid crystal display device as claimed in claim 2, wherein the sectional shape of the protrusions is ellipsoidal.
Claim 24
Dependent Claim
19 words
A liquid crystal display device as claimed in claim 2, wherein the sectional shape of the protrusions is parabolic.
Claim 25
Dependent Claim
19 words
A liquid crystal display device as claimed in claim 2, wherein the sectional shape of the protrusions is arcuate.
Claim 26
Dependent Claim
21 words
A liquid crystal display device as claimed in claim 2, wherein the protrusions are identical in shape but differ in size.
Claim 27
Dependent Claim
17 words
A liquid crystal display device as claimed in claim 2, wherein the protrusions have plural different shapes.
Claim 28
Dependent Claim
31 words
A liquid crystal display device as claimed in claim 2, wherein the array density of the protrusions increases continuously or in steps, in proportion to the distance from the light source.
Claim 29
Dependent Claim
31 words
A liquid crystal display device as claimed in claim 2, wherein the size of the protrusions increases, either continuously or in steps, in proportion to the distance from the light source.
Claim 30
Dependent Claim
27 words
A liquid crystal display device as claimed in claim 2, wherein the protrusions are disposed in regions other than the pixels of the liquid crystal display element.
Claim 31
Dependent Claim
73 words
A liquid crystal display device as claimed in claim 1, wherein the liquid crystal display element side surface of the light guide plate is coated with a film made of a light transmitting material with a refractive index which is lower than that of the light guide plate, and the film thickness of the coating film is decreased, either continuously or in steps, in inverse proportion to the distance from the light source.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-08-22 | 1998-02-21 | 1998-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-08-22 | 2002-02-21 | 2002-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-08-22 | 2006-02-21 | 2006-08-23 | $7700.00 | Window Closed / Lapsed |