# US 10,502,957 B2 · Virtual image display apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,502,957 B2 - Document ID: US10502957B2 - Status: Granted - Kind: B2 - Application number: 14/561,631 - Filed: 2014-12-05 - Published: 2015-06-25 - Granted: 2019-12-10 - Earliest claimed: 2013-12-25 - Assignees: Seiko Epson Corporation - Applicants: Seiko Epson Corporation - Inventors: Noriaki Hiraide; Masayuki Takagi - Web page: https://patentgrep.com/patent/US10502957B2 ## CPC - G02B 27/0172: {characterised by optical features} - G02B 27/0006: {with means to keep optical surfaces clean, e.g. by preventing or removing dirt, stains, contamination, condensation (G02B1/18 takes precedence; cleaning in general B08B)} - G02B 27/0176: {characterised by mechanical features} - G02B 2027/012: {comprising devices for attenuating parasitic image effects} - G02B 2027/0145: {creating an intermediate image} - G02B 2027/0178: {Eyeglass type (eyeglass details G02C)} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract In relation to a fourth surface as a partially covered optical surface from among a plurality of optical surfaces which configure a light guiding member in a light guiding device, such as a first surface, an intermediate image is formed at a location separated from the partially covered optical surface (fourth surface). With such a configuration, it is possible to reduce the influence of dirt, contamination, or the like on an image even if the dirt, the contamination, or the like are generated on the partially covered optical surface (fourth surface), from which it is difficult or impossible to remove the dirt, the contamination, or the like, and to display an image with a wide image angle by a configuration forming an intermediate image. ## Claims ### Claim 1 A virtual image display apparatus comprising: a video image element which forms video image light; a light guiding member which has a plurality of optical surfaces, guides video image light from the video image element by reflecting the video image light by an internal surface, and forms an intermediate image; and a coupling member which is arranged between the video image element and the light guiding member, is coupled to the light guiding member, and partially covers the light guiding member, wherein the light guiding member includes, in the plurality of optical surfaces, a partially covered optical surface from a first region which is covered with the coupling member to a second region which is not covered with the coupling member, and the intermediate image is formed at a location separated from the partially covered optical surface. ### Claim 2 (depends on 1) The virtual image display apparatus according to claim 1, wherein in the light guiding member, the intermediate image is formed in a range from a side separating inward from the partially covered optical surface to a side of a surface which faces the partially covered optical surface. ### Claim 3 (depends on 1) The virtual image display apparatus according to claim 1, further comprising: a dust proofing structure formed at least between the partially covered optical surface and an end portion of the coupling member between the light guiding member and the coupling member. ### Claim 4 (depends on 3) The virtual image display apparatus according to claim 3, wherein the dust proofing structure is formed so as to be in contact with an effective light guiding region in the partially covered optical surface and includes a sealing member which seals the partially covered optical surface and the coupling member together. ### Claim 5 (depends on 4) The virtual image display apparatus according to claim 4, wherein the sealing member extends along a boundary between the first region and the second region and is in contact with the effective light guiding region on the partially covered optical surface in a light guiding direction, in which the video image light is guided, with a width of equal to or less than 0.5 mm. ### Claim 6 (depends on 3) The virtual image display apparatus according to claim 3, wherein the dust proofing structure is an elastic member. ### Claim 7 (depends on 1) The virtual image display apparatus according to claim 1, wherein the light guiding member has a surface-textured portion on a surface other than the effective light guiding region. ### Claim 8 (depends on 1) The virtual image display apparatus according to claim 1, wherein the coupling member is a lens tube portion which accommodates a projector lens projecting light from the video image element toward the light guiding member. ### Claim 9 (depends on 8) The virtual image display apparatus according to claim 8, wherein the lens tube portion has a fitting structure which is fitted onto the light guiding member. ### Claim 10 (depends on 1) The virtual image display apparatus according to claim 1, wherein the partially covered optical surface is a non-axisymmetric spherical surface. ### Claim 11 (depends on 1) The virtual image display apparatus according to claim 1, wherein the light guiding member includes four or more surfaces as the plurality of optical surfaces such that a first surface and a third surface from among the plurality of optical surfaces are arranged to face each other, wherein the video image light from the video image element is fully reflected by the third surface, is fully reflected by the first surface, is reflected by the second surface, then transmits through the first surface, and reaches a viewing side, wherein the first surface and the third surface of the light guiding member are substantially parallel planes, and wherein the partially covered optical surface is arranged to face the third surface and corresponds to a fourth surface which fully reflects the video image light from the video image element and guides the reflected video image light to the third surface. ### Claim 12 (depends on 11) The virtual image display apparatus according to claim 11, wherein the intermediate image is formed on a side which is closer to the third surface than to the fourth surface in the light guiding member. ### Claim 13 (depends on 1) The virtual image display apparatus according to claim 1, further comprising: a light transmitting member which is attached to the light guiding member such that external light and the video image light are visually recognized in an overlapped manner.