# US 2017/0255014 A1 · Light guide device and virtual-image display device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0255014 A1 - Document ID: US20170255014A1 - Status: Published application - Kind: A1 - Application number: 15/425,209 - Filed: 2017-02-06 - Published: 2017-09-07 - Earliest claimed: 2016-03-07 - Assignees: Seiko Epson Corporation - Applicants: Seiko Epson Corporation - Inventors: Akira KOMATSU; Takahiro TOTANI; Takashi TAKEDA; Masayuki TAKAGI; Toshiaki MIYAO; Hayato MATSUKI - Web page: https://patentgrep.com/patent/US20170255014A1 ## CPC - G02B 27/0172: {characterised by optical features} - G02B 5/3041: {comprising multiple thin layers, e.g. multilayer stacks} - G02B 6/0035: {provided on the surface of the light guide or in the bulk of it} - G02B 6/0055: {Reflecting element, sheet or layer} - G02B 6/0056: {for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements} - G02B 27/0101: {characterised by optical features (G02B27/0172 takes precedence)} - G02B 27/285: {comprising arrays of elements, e.g. microprisms} - G02B 2027/0118: {comprising devices for improving the contrast of the display / brillance control visibility} - G02B 2027/012: {comprising devices for attenuating parasitic image effects} - G02B 2027/0125: {Field-of-view increase by wavefront division} - G02B 2027/0178: {Eyeglass type (eyeglass details G02C)} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract A light guide device includes an incident section, a parallel light guide body for light guide, and an emitting section. The emitting section includes a reflection unit formed by arraying a plurality of mirrors. The plurality of mirrors configuring the reflection unit are reflection elements having reflectance of P polarized light lower than reflectance of S polarized light. The plurality of mirrors configuring the reflection unit can be accompanied by wavelength plates to be adjacent to the mirrors. ## Claims ### Claim 1 A light guide device comprising: a light guide body including a pair of opposed surfaces corresponding to an observer side and an external environment side; an incident section provided on one end side of the light guide body; and an emitting section provided on the other end side of the light guide body, wherein the emitting section includes a reflection unit formed by arraying a plurality of mirrors that respectively emit video lights received from the incident section to the observer side, and the plurality of mirrors are reflection elements having reflectance of P polarized light lower than reflectance of S polarized light. ### Claim 2 (depends on 1) The light guide device according to claim 1, wherein the light guide device is used in combination with a shade member that covers the exterior environment side of the light guide body and has the transmittance of the P polarized light based on the mirrors higher than the transmittance of the S polarized light based on the mirrors. ### Claim 3 (depends on 1) The light guide device according to claim 1, wherein the plurality of mirrors allow each of the video lights to pass twice at most. ### Claim 4 (depends on 1) The light guide device according to claim 1, wherein the pair of surfaces of the light guide body extends in substantially parallel, the plurality of mirrors are inclined to the incident section side toward the external environment side in order to reflect the video lights reflected on the external environment side of the light guide body and respectively emit the video lights to the observer side, the light guide device is used in combination with a shade member that covers the external environment side of the light guide body, and in the shade member, the transmittance of the P polarized light, which is an electric field component in a first direction substantially parallel to a light guide direction of the light guide body, in external light is higher than the transmittance of the S polarized light, which is an electric field component in a second direction crossing the first direction, in the external light. ### Claim 5 (depends on 1) A virtual-image display device comprising: a video element configured to generate video light; and the light guide device according to claim 1. ### Claim 6 (depends on 5) The virtual-image display device according to claim 5, wherein video light having a polarization characteristic deviating to a predetermined direction is emitted from the video element. ### Claim 7 (depends on 5) The virtual-image display device according to claim 5, wherein an optical element is present that gives a polarization characteristic deviating to a predetermined direction to an optical path extending from the video element to the plurality of mirrors through an optical surface of the light guide body. ### Claim 8 (depends on 1) The light guide device according to claim 1, wherein the reflection unit includes a plurality of wavelength plates disposed to respectively correspond to the plurality of mirrors. ### Claim 9 (depends on 8) The light guide device according to claim 8, wherein the wavelength plates are disposed adjacent to the mirrors. ### Claim 10 (depends on 9) The light guide device according to claim 9, wherein the wavelength plates are disposed, with respect to the mirrors, on a counter-incident side away from the incident section. ### Claim 11 (depends on 9) The light guide device according to claim 9, wherein the wavelength plates are disposed, with respect to the mirrors, on an incident side where the incident section is present. ### Claim 12 (depends on 8) The light guide device according to claim 8, wherein the wavelength plates are half wavelength plates. ### Claim 13 (depends on 8) A virtual-image display device comprising: a video element configured to generate video light; and the light guide device according to claim 8. ### Claim 14 (depends on 1) The light guide device according to claim 1, wherein the mirror is formed by dielectric multilayer films. ### Claim 15 (depends on 1) The light guide device according to claim 1, wherein, when the reflectance of the P polarized light of the mirrors is represented as Rp and the reflectance of the S polarized light of the mirrors is represented as Rs, following conditional expressions (1) and (2) are satisfied: Rp<0.05 (1) Rp<0.5×Rs (2). ### Claim 16 (depends on 1) The light guide device according to claim 1, wherein the pair of surfaces of the light guide body extends in substantially parallel, and the plurality of mirrors are inclined to the incident section side toward the external environment side in order to reflect the video lights reflected on the external environment side of the light guide body and respectively emit the video lights to the observer side. ### Claim 17 (depends on 1) The light guide device according to claim 1, wherein an incident angle of the video lights on the mirrors is equal to or larger than 40°. ### Claim 18 (depends on 1) The light guide device according to claim 1, further comprising a shade member configured to cover the external environment side of the light guide body and have a polarization characteristic deviating to a predetermined direction.