# US 2017/0290131 A1 · Projection device

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- Number: US 2017/0290131 A1
- Document ID: US20170290131A1
- Status: Published application
- Kind: A1
- Application number: 15/472,626
- Filed: 2017-03-29
- Published: 2017-10-05
- Earliest claimed: 2016-03-31
- Assignees: Funai Electric Co., Ltd.
- Applicants: Funai Electric Co., Ltd.
- Inventors: Tatsuya ITO
- Web page: https://patentgrep.com/patent/US20170290131A1

## CPC

- H05B 47/14: by determining electrical parameters of the light source
- B60K 35/10: Input arrangements, i.e. from user to vehicle, associated with vehicle functions or specially adapted therefor
- B60K 35/235: with means for detecting the driver's gaze direction or eye points
- B60K 35/60: Instruments characterised by their location or relative disposition in or on vehicles (arrangements of lighting devices on dashboards B60Q3/10)
- B60K 35/81: for controlling displays
- B60R 25/24: using electronic identifiers containing a code not memorised by the user
- G02B 5/30: Polarising elements (light-modulating devices with active elements G02F1/00)
- G02B 26/0833: {the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD (G02B26/0825 takes precedence; micromechanical devices in general B81B)}
- G02B 27/01: Head-up displays
- G02B 27/0101: {characterised by optical features (G02B27/0172 takes precedence)}
- G06K 7/10227: {loading programming parameters or programs into the interrogator, e.g. for configuring the interrogator}
- G07C 9/00309: {operated with bidirectional data transmission between data carrier and locks}
- H01S 5/4012: {Beam combining, e.g. by the use of fibres, gratings, polarisers, prisms}
- H01S 5/4093: {Red, green and blue [RGB] generated directly by laser action or by a combination of laser action with nonlinear frequency conversion}
- H04L 9/0822: {using key encryption key}
- H04L 9/0838: {Key agreement, i.e. key establishment technique in which a shared key is derived by parties as a function of information contributed by, or associated with, each of these (network architectures or network communication protocols for key exchange in a packet data network H04L63/061)}
- H04L 9/0844: {with user authentication or key authentication, e.g. ElGamal, MTI, MQV-Menezes-Qu-Vanstone protocol or Diffie-Hellman protocols using implicitly-certified keys}
- H04L 9/0861: {Generation of secret information including derivation or calculation of cryptographic keys or passwords}
- H04L 9/0897: {involving additional devices, e.g. trusted platform module [TPM], smartcard or USB}
- H04L 9/14: using a plurality of keys or algorithms
- H04L 9/3013: {involving the discrete logarithm problem, e.g. ElGamal or Diffie-Hellman systems}
- H04L 9/3066: {involving algebraic varieties, e.g. elliptic or hyper-elliptic curves}
- H04L 9/3263: {involving certificates, e.g. public key certificate [PKC] or attribute certificate [AC]; Public key infrastructure [PKI] arrangements (network architectures or network communication protocols for supporting authentication of entities using certificates in a packet data network H04L63/0823)}
- H04L 9/3268: {using certificate validation, registration, distribution or revocation, e.g. certificate revocation list [CRL]}
- H04L 9/3271: {using challenge-response}
- H04L 63/0428: {wherein the data content is protected, e.g. by encrypting or encapsulating the payload}
- H04L 63/061: {for key exchange, e.g. in peer-to-peer networks (cryptographic mechanisms or cryptographic arrangements for key agreement H04L9/0838)}
- H04N 9/3129: {scanning a light beam on the display screen (scanning a light beam on a screen in displays other than projection devices G09G3/02; scanning systems in general G02B26/10; projectors using laser light sources in general H04N9/3161)}
- H04N 9/3155: {for controlling the light source (light source control per se H05B35/00 – H05B47/00; control of an illumination source for displays in general G09G3/3406)}
- H04N 9/3167: {for polarizing the light beam (polarizing optical systems per se G02B27/28)}
- H04W 12/04: Key management, e.g. using generic bootstrapping architecture [GBA]
- H04W 12/50: Secure pairing of devices
- H05B 47/11: by determining the brightness or colour temperature of ambient light
- B60K 35/213: {Virtual instruments}
- B60K 2360/23: using reflectors
- B60K 2360/25: using filters
- B60K 2360/27: using semi-transparent optical elements
- B60K 2360/31: Virtual images
- B60K 2360/334: Projection means
- B60K 2360/77: Instrument locations other than the dashboard
- B60R 2325/108: Encryption
- G02B 2027/0118: {comprising devices for improving the contrast of the display / brillance control visibility}
- G07C 2009/00769: {with data transmission performed by wireless means}
- H04L 2209/24: Key scheduling, i.e. generating round keys or sub-keys for block encryption
- H04L 2209/80: Wireless
- H04L 2209/805: Lightweight hardware, e.g. radio-frequency identification [RFID] or sensor
- H04L 2209/84: Vehicles
- Y02B 20/40: Control techniques providing energy savings, e.g. smart controller or presence detection
- H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- 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
- B60R: VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G06K: GRAPHICAL DATA READING (image or video recognition or understanding G06V); PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G07C: TIME OR ATTENDANCE REGISTERS; REGISTERING OR INDICATING THE WORKING OF MACHINES; GENERATING RANDOM NUMBERS; VOTING OR LOTTERY APPARATUS; ARRANGEMENTS, SYSTEMS OR APPARATUS FOR CHECKING NOT PROVIDED FOR ELSEWHERE
- H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS

## Abstract

A projection device comprises a light source, a first attenuator and a second attenuator, a first driver, a second driver, a light receiving element, and a controller. The light source emits light. The first attenuator and the second attenuator attenuate intensity of the light from the light source. The first driver drives the first attenuator. The second driver drives the second attenuator. The light receiving element receives the light distributed by the second attenuator. The controller controls the second driver to control the distribution ratio of the light distributed to the light receiving element by the second attenuator according to control of transmissivity of light at the first attenuator by the first driver.

## Claims

### Claim 1

A projection device comprising:
a light source that emits light;
a first attenuator and a second attenuator that attenuate intensity of the light from the light source;
a first driver that drives the first attenuator;
a second driver that drives the second attenuator;
a light receiving element that receives the light distributed by the second attenuator; and
a controller that controls the second driver to control distribution ratio of the light distributed to the light receiving element by the second attenuator according to control of transmissivity of the light at the first attenuator by the first driver.

### Claim 2 (depends on 1)

The projection device according to claim 1, wherein
the controller controls the second driver to increase the distribution ratio of the light distributed to the light receiving element by the second attenuator in response to controlling the first driver to reduce the transmissivity of the light at the first attenuator.

### Claim 3 (depends on 1)

The projection device according to claim 1, wherein
the controller controls the second driver to increase the distribution ratio by switching drive of the second attenuator stepwisely.

### Claim 4 (depends on 3)

The projection device according to claim 3, wherein
the controller controls the second driver to switch the drive of the second attenuator after controlling the first driver to temporarily increase the transmissivity of the light at the first attenuator.

### Claim 5 (depends on 3)

The projection device according to claim 3, wherein
the controller controls the second driver to increase the distribution ratio by switching the drive of the second attenuator in two stages.

### Claim 6 (depends on 1)

The projection device according to claim 1, wherein
the light source includes a plurality of light emission elements that outputs different colors of light, and
a first transmissivity characteristics indicating a relation between the transmissivity of the light at the first attenuator for each color and a drive voltage of the first attenuator and a second transmissivity characteristics indicating a relation between the transmissivity of the light at the second attenuator for each color and a drive voltage of the second attenuator are different from each other.

### Claim 7 (depends on 6)

The projection device according to claim 6, wherein
a descending order of transmissivities of the colors at a given drive voltage in a drive voltage region of the first transmissivity characteristics is reversed from a descending order of transmissivities of the colors at a given drive voltage in a drive voltage region of the second transmissivity characteristics.

### Claim 8 (depends on 1)

The projection device according to claim 1, wherein
the first attenuator includes a first liquid crystal element and a first polarizer, and
the second attenuator includes a second polarizer, a second liquid crystal element, and a third polarizer.

### Claim 9 (depends on 8)

The projection device according to claim 8, wherein
the first polarizer and the second polarizer are formed by a single polarizer.

### Claim 10 (depends on 8)

The projection device according to claim 8, wherein
the first polarizer and the second polarizer are formed by separate polarizers.

### Claim 11 (depends on 8)

The projection device according to claim 8, wherein
a first relative polarization angle θ1 at the first attenuator is 45 degrees<θ1<135 degrees, where the first relative polarization angle θ1 being a relative angle between a polarization azimuth angle of the light incident on the first liquid crystal element and a polarization azimuth angle of the light emitted from the first polarizer that is disposed downstream along an optical path of the light relative to the first liquid crystal element, and
a second relative polarization angle θ2 at the second attenuator is 135 degrees<θ2<225 degrees, where the second relative polarization angle θ2 being a relative angle between a polarization azimuth angle of the light incident on the second liquid crystal element and a polarization azimuth angle of the light emitted from the third polarizer that is disposed downstream along the optical path of the light relative to the second liquid crystal element.

### Claim 12 (depends on 11)

The projection device according to claim 11, wherein
the first relative polarization angle θ1 is 90 degrees, and
the second relative polarization angle θ2 is 180 degrees.

### Claim 13 (depends on 8)

The projection device according to claim 8, wherein
the first attenuator further includes a fourth polarizer that is disposed upstream along an optical path of the light relative to the first liquid crystal element.

### Claim 14 (depends on 13)

The projection device according to claim 13, wherein
a polarization direction of the fourth polarizer is adjustable according to a polarization direction of the light incident on the first liquid crystal element.

### Claim 15 (depends on 8)

The projection device according to claim 8, further comprising
a second light receiving element that receives the light distributed by and emitted from the first polarizer.

### Claim 16 (depends on 8)

The projection device according to claim 8, wherein
the first attenuator is disposed upstream along an optical path of the light relative to the second attenuator.

### Claim 17 (depends on 16)

The projection device according to claim 16, wherein
the first liquid crystal element is disposed upstream along the optical path of the light relative to the first polarizer, and
the second liquid crystal element is disposed between the second polarizer and the third polarizer along the optical path of the light.

### Claim 18 (depends on 8)

The projection device according to claim 8, wherein
the first liquid crystal element and the second liquid crystal element are formed by a single liquid crystal element.

### Claim 19 (depends on 8)

The projection device according to claim 8, further comprising
a first prism,
a second prism coupled to the first prism, and
a third prism coupled to the second prism,
the first polarizer being formed by the first prism and the second prism, and
the second polarizer being formed by the second prism and the third prism.

### Claim 20 (depends on 19)

The projection device according to claim 19, wherein
the light reflected at an interface between the first prism and the second prism is incident on an interface between the second prism and the third prism.