EP0684423A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Backlight device for display apparatus
Assignee: Canon Inc
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Filing: 1995-05-26
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Granted: —
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Expires: 2015-05-26
Abstract
Abstract A backlight device suitable for illuminating a transmission-type display device, such as a liquid crystal device, is constituted by a reflection member (10) for reflecting light, a transmission member (11) disposed opposite to the reflection member (10) so as to form a space (S) from the reflection member (10), and a light source (1) disposed to emit light into the space (S). Light issued from the light source (1) into the space (S) is reflected by the reflection member (10) and transmitted through the transmission member (11). The transmission member (11) is preferably provided with a reflection layer (12) having apertures (13) having an aperture ratio which increases with an increase in distance from the light source (1) toward a centre of the space (S) as a linear function, a hyperbolic function or a function intermediate therebetween of the distance from the light source (1). Between the transmission member (11) and a display device, a prism sheet (16,17) and/or a diffusion sheet may be disposed so as to improve the frontal illumination performance.
Inventors
- 👤 Katsumi C/O Canon K.K. Kurematsu
- 👤 Yoshihiro C/O Canon K.K. Onitsuka
- 👤 Toshiyuki C/O Canon K.K. Kanda
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 13:15
CPC Classifications
G; G02; G02B; G02B23/00; G02B23/14; G02B6/00; G02B6/0001; G02B6/0011; G02B6/0033; G02B6/005; G02B6/0053; F; F21; F21V; F21V11/00; F21V11/08; F21V11/14; F21V13/00; F21V13/12; F21V13/14; F21V7/00; G02B6/0055; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1335; G02F1/1336; G02F1/13362; G02B6/0013; G02B6/0023; G02B6/0031; G02F1/133528; G02F1/133536; G02F1/13355; G02F1/133615
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
63 words
A backlight device, comprising: reflection means for reflecting light, a transmission member disposed opposite to the reflection means so as to form a space from the reflection means, and a light source disposed to emit light into the space, so that light issued from the light source into the space shall be reflected by the reflection means and transmitted through the transmission member.
Claim 2
Dependent Claim
63 words
A backlight device, comprising: reflection means for reflecting light, a transmission member disposed opposite to the reflection means so as to form a space from the reflection means, and a light source disposed to emit light into the space, so that light issued from the light source into the space shall be reflected by the reflection means and transmitted through the transmission member.
Claim 3
Dependent Claim
57 words
A backlight device according to Claim 1, wherein said transmission member is provided with a reflection layer having a multitude of apertures, so that the light issued from the light source into the space is repetitively reflected by the reflection means and the reflection layer to be leaked outwards through the transmission member out of the apertures.
Claim 4
Dependent Claim
35 words
A backlight device according to Claim 2, wherein the apertures are arranged to have an area per unit region of the transmission member, which area increases with an increase in distance from the light source.
Claim 5
Dependent Claim
36 words
A backlight device according to Claim 2 or 3, wherein said reflection means is provided with a scattering layer for scattering and reflecting light on a face of the reflection means opposite to the reflection layer.
Claim 6
Dependent Claim
42 words
A backlight device according to Claim 4, wherein said scattering layer is provided with a multitude of apertures arranged to have an area per unit region of the scattering layer, which area decreases with an increase in distance from the light source.
Claim 7
Dependent Claim
95 words
A backlight device according to Claim 1, further including a polarization beam splitter supported on the transmission member for selectively transmitting a p-polarization component and reflecting an s-polarization component, and a quarter wave plate disposed on the reflection means and opposite to the transmission member for causing conversion between the p-polarization component and the s-polarization component, whereby light emitted from the light source into the space is reflected between the polarization beam splitter layer and the reflection means so that the p-polarization component of the emitted light is selectively leaked outwards through the transmission member.
Claim 8
Dependent Claim
62 words
A backlight device according to Claim 1, wherein said light transmission member is provided with a reflection layer having a multitude of apertures having an aperture ratio which increases with an increase in distance from the light source toward a centre of the space as a linear function, a hyperbolic function, or a function intermediate therebetween,of the distance from the light source.
Claim 9
Dependent Claim
59 words
A backlight device according to Claim 1, further including at least one sheet of prism means disposed on a side of the transmission member opposite to the reflection means, so that the light transmitted through the transmission member is further transmitted through the prism means while being deflected in a direction deviated toward a normal to the transmission member.
Claim 10
Dependent Claim
16 words
A backlight device according to Claim 8, wherein said prism means is provided in plural sheets.
Claim 11
Dependent Claim
21 words
A backlight device according to Claim 9, wherein a diffusion means is interposed between the plural sheets of the prism means.
Claim 12
Dependent Claim
17 words
A backlight device according to Claim 8, wherein a single sheet of the prism means is provided.
Claim 13
Dependent Claim
28 words
A backlight device according to Claim 8, wherein said prism means is disposed so that the prism ridges have apex angles directed away from the first reflection means.
Claim 14
Dependent Claim
27 words
A backlight device according to Claim 8, wherein said prism means is disposed so that the prism ridges have apex angles directed toward the first reflection means.
Claim 15
Dependent Claim
24 words
A backlight device according to Claim 8, wherein the prism ridges of the prism means have an apex angle of at most 90 degrees.
Claim 16
Dependent Claim
24 words
A backlight device according to Claim 14, wherein the prism ridges of the prism means have an apex angle of 50 - 70 degrees.
Claim 17
Dependent Claim
49 words
A backlight device according to Claim 8, wherein said second reflection means has an aperture ratio distribution which increases with an increase in distance from the linear light source in a linear function, a hyperbolic function or a function intermediate therebetween of the distance from the linear light source.
Claim 18
Dependent Claim
44 words
A backlight device according to Claim 8, wherein said second reflection means is disposed in a film formed in a pattern of a mesh or discrete dots supported on a front transmission plate disposed spaced apart from and in parallel with said first means.
Claim 19
Dependent Claim
42 words
A display apparatus, comprising: a backlight device according to any one of Claims 1 - 17, a backlight drive means for driving the backlight device, a display device illuminated by the backlight device, and a drive means for driving the display device.
Claim 20
Dependent Claim
17 words
A display apparatus according to Claim 19, wherein the display device is a liquid crystal display device.
References Cited (Backward Citations)
JPS57128383A
Cited
JPS6313202A
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JPH0239118A
Cited
JPH0471105A
Cited
US5381256A
Cited
JPH05281541A
Cited
JPH05323318A
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JPH0618873A
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