VIDEO PROJECTION DEVICE AND HEAD MOUNTED DISPLAY USING THE SAME

• US 20160041396A1
• Filed: 08/04/2015
• Published: 02/11/2016
• Est. Priority Date: 08/05/2014
• Status: Active Grant

• Current Assignee: Hitachi-Lg Data Storage Incorporated (Hitachi, Ltd.)
• Original Assignee: Hitachi-Lg Data Storage Incorporated (Hitachi, Ltd.)
• Inventors: KAWAMURA, Tomoto, NAKAMURA, Toshiteru, SEO, Yoshiho, OUCHI, Satoshi, OKAMOTO, Yoshio, SAITO, Hidenao, KIYA, Kenji
• Granted Patent: US 10,466,490 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G02B 17/006 Systems in which light light is reflected on a plurality of parallel surfaces, e.g. louvre mirrors, total internal reflection [TIR] lenses Fresnel mirrors G02B5/09, Fresnel lenses G02B3/08
• CPC Class Codes: G02B 2027/0112 comprising device for genereting colour display
• CPC Class Codes: G02B 2027/0118 comprising devices for improving the contrast of the display / brillance control visibility
• CPC Class Codes: G02B 2027/014 comprising information/image processing systems
• CPC Class Codes: G02B 2027/015 involving arrangement aiming to get less bulky devices
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 27/0176 characterised by mechanical features

Abstract

A video projection device 001 includes a video generation section 041 that has a micro display element 003 which generates video and an illuminating optical system 002 which illuminates a micro display element; projection section 043 that project the video which is generated by the video generation section onto the eyes of a user through an eyepiece section; and a mechanical support section 042 that connects the video generation section to the projection section using a housing section. The mechanical support section includes at least one transparent area 011 that is surrounded by the housing section, and penetrates in a direction parallel to a direction in which the video from the projection section is projected. The illuminating optical system includes a light source that emits light in a plurality of wavelength bands, and a controller 440 that controls the output of the light source.

Claims

1. A video projection device which projects video onto an eye of a user, comprising:

a video generation section that includes a micro display element which generates the video, and an illuminating optical system which illuminates the micro display element;

a projection section that projects the video, which is generated by the video generation section, onto the eye of the user through an eyepiece section; and

a mechanical support section that connects the video generation section to the projection section using a housing section,

wherein the mechanical support section is surrounded by the housing section between the video generation section and the projection section, and includes at least one transparent area which penetrates in a direction parallel to a direction into which the video from the projection section is projected.

2. The video projection device according to claim 1,

wherein the housing section of the mechanical support section is arranged to block external light which passes through the transparent area and is incident into the micro display element.

3. The video projection device according to claim 2,

wherein, in an opening width in a direction which faces the projection section from the video generation section of the transparent area, an opening width on aside which is close to the eyepiece section is wider than an opening width on a side which is far from the eyepiece section.

4. The video projection device according to claim 1,

wherein the illuminating optical system of the video generation section includes:

a light source that emits light in a plurality of wavelength bands;

a square columnar light integrator that causes light, which is emitted from the light source, to be internally reflected, integrates light intensities, and makes uniform light; and

a lens section that converts light, which is emitted from the light integrator, into light which is approximately parallel, and

wherein a light emission surface on a side of the lens section of the light integrator has a diffusion function of diffusing light.

5. The video projection device according to claim 4,

wherein the light source includes three light source bodies that emits light in red, green, and blue wavelength bands, and

wherein a central point of each of the light source bodies is arranged to be a vertex position of a triangle having an angle which is equal to or less than 90 degrees.

6. The video projection device according to claim 4,

wherein, when it is assumed that an angle of light which is emitted from the light integrator is θ

, a half angle at half maximum of the diffusion function of the light integrator is θ

d, a length of the light integrator is L, a width is W, a height is H, a refractive index is N, and a desired integration number in the light integrator is Ip, a relationship in which

(π

·

L2/(W·

H))·

tan 2(θ

/N+θ

d)Ip is satisfied.

7. The video projection device according to claim 6,

wherein a length L of the light integrator is in a range of 3.1 mm to 4 mm, and the half angle at half maximum θ

d of the diffusion function is 40 degrees.

8. The video projection device according to claim 5,

wherein an angle conversion surface is provided on an incident surface of the light integrator such that light in the red, green, and blue wavelength bands which is incident from the light source progresses toward a center of the light emission surface of each of the light integrators.

9. The video projection device according to claim 5,

wherein a concave lens is provided on an incident surface of the light integrator such that light in the red, green, and blue wavelength bands which is incident from the light source progresses toward a center of the light emission surface of each of the light integrators.

10. A head mounted display on which a video projection device that projects video onto an eye of a user is mounted,

wherein the video projection device includes:

a video generation section that includes a micro display element which generates the video, and an illuminating optical system which illuminates the micro display element;

a projection section that projects the video, which is generated by the video generation section, onto the eye of the user through an eyepiece section; and

a mechanical support section that connects the video generation section to the projection section using a housing section,

wherein the illuminating optical system includes a light source that emits light in a plurality of wavelength bands, and

wherein the mechanical support section includes;

at least one transparent area which is surrounded by the housing section between the video generation section and the projection section, and which penetrates in a direction parallel to a direction into which the video from the projection section is projected; and

a controller that controls the video which is projected from the video projection device.

11. The head mounted display according to claim 10, further comprising:

a light quantity detection section that detects light quantity of each of the wavelength bands of the light source; and

a data table that stores an initial setting value of the light quantity of each of the wavelength bands of the light source,

wherein the controller compares the light quantity of each of the wavelength bands, which is detected by the light quantity detection section, with the initial setting value of the light quantity of each of the wavelength bands, which is stored in the data table, and controls an output of the light source according to difference quantity thereof.

12. The head mounted display according to claim 10,

wherein the illuminating optical system includes the light source that emits light in a red wavelength band,

wherein the head mounted display further includes:

a red light quantity detection section that detects light quantity of the red wavelength band of the light source; and

a data table that stores an initial setting value of the light quantity of the red wavelength band of the light source and temperature dependency data of the emitted light quantity of each wavelength band, and

wherein the controller compares the light quantity of the red wavelength band, which is detected by the red light quantity detection section, with the initial setting value of the light quantity of the red wavelength band, which is stored in the data table, controls output of the light source of the red wavelength band based on a difference quantity, acquires change in the temperature of the light source with reference to the temperature dependency data of the emitted light quantity of the red wavelength band which is stored in the data table, refers to the temperature dependency data of the emitted light quantity of each of the wavelength bands, which are stored in the data table, other than the red wavelength band, and controls the output of the light source of each of the wavelength bands other than the red wavelength band according to the change in the temperature.

13. The head mounted display according to claim 10, further comprising:

a temperature detection section that detects temperature in a vicinity of the light source; and

a data table that stores an initial value of the temperature in the vicinity of the light source, and the temperature dependency data of the emitted light quantity of each of the wavelength bands,

wherein the controller acquires a change in the temperature by comparing the temperature which is detected by the temperature detection section with the initial setting value of the temperature stored in the data table, refers to the temperature dependency data of the emitted light quantity of each of the wavelength bands, which is stored in the data table, and controls output of the light source according to the change in the temperature.