# US 11,029,517 B2 · Virtual image display device

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- Number: US 11,029,517 B2
- Document ID: US11029517B2
- Status: Granted
- Kind: B2
- Application number: 16/448,194
- Filed: 2019-06-21
- Published: 2019-10-10
- Granted: 2021-06-08
- Earliest claimed: 2017-06-30
- Assignees: JVC KENWOOD Corporation
- Applicants: JVC KENWOOD Corporation
- Inventors: Manabu Kobayashi
- Web page: https://patentgrep.com/patent/US11029517B2

## CPC

- G02B 27/0101: {characterised by optical features (G02B27/0172 takes precedence)}
- B60K 35/23: Head-up displays [HUD] (optical aspects of head-up displays G02B27/01)
- B60K 35/60: Instruments characterised by their location or relative disposition in or on vehicles (arrangements of lighting devices on dashboards B60Q3/10)
- G02B 27/01: Head-up displays
- G02B 27/0149: {characterised by mechanical features (G02B27/0176 takes precedence)}
- B60K 35/213: {Virtual instruments}
- B60K 2360/23: using reflectors
- B60K 2360/31: Virtual images
- B60K 2360/334: Projection means
- G02B 5/10: with curved faces
- G02B 17/08: Catadioptric systems {(used in non-imaging applications G02B19/00)}
- G02B 2027/012: {comprising devices for attenuating parasitic image effects}
- G02B 2027/0159: {with mechanical means other than scaning means for positioning the whole image}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- B60K: ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES

## Abstract

A virtual image display device includes: a display unit that generates an image display light by modulating an illumination light; and a projection optical system that includes a concave mirror for reflecting the image display light toward a virtual image presentation plate and a convex lens provided between the display unit and the concave mirror. The display unit is provided at a position closer to the convex lens than a focal point, within a meridional plane, of a composite optical system formed by the virtual image presentation plate and the projection optical system.

## Claims

### Claim 1

A virtual image display device comprising:
a display unit that generates an image display light by modulating an illumination light; and
a projection optical system that includes a concave mirror for reflecting the image display light toward a virtual image presentation plate and a convex lens provided between the display unit and the concave mirror, wherein
the display unit is provided at a position closer to the convex lens than a focal point, within a meridional plane, of a composite optical system formed by the virtual image presentation plate and the projection optical system, and
a focal distance of the concave mirror is longer than a focal distance of the convex lens.

### Claim 2 (depends on 1)

The virtual image display device according to claim 1, wherein
the focal distance of the concave mirror is not less than 1.5 times and not more than 3 times the focal distance of the convex lens.

### Claim 3 (depends on 1)

The virtual image display device according to claim 1, wherein
denoting a ratio of magnification of a virtual image by the composite optical system by β, and a focal distance of the composite optical system within the meridional plane by fM, the display unit is provided at a distance d=fM/β from the focal point of the composite optical system within the meridional plane.

### Claim 4 (depends on 1)

The virtual image display device according to claim 1, wherein
the virtual image presentation plate is a windshield provided in a vehicle and having a uniform thickness.