Vehicular interior rearview mirror assembly with near infrared light emitter and DMS camera and light absorption filter

Patent metadata

Field	Value
Publication number	US-12289564-B2
Application number	US-202318472315-A
Country	US
Kind code	B2
Filing date	Sep 22, 2023
Priority date	Sep 26, 2022
Publication date	Apr 29, 2025
Grant date	Apr 29, 2025

Abstract

A cabin monitoring system includes an interior rearview mirror assembly including a mirror head having a mirror reflective element that includes (i) a planar glass substrate, (ii) a transflective mirror reflector at the glass substrate and (iii) a light absorption film including a polarizer film. A camera accommodated by the mirror head views through the reflective element. A light emitter accommodated by the mirror head emits near infrared (NIR) light through the reflective element. The light absorption film attenuates greater than 60 percent of visible light and less than 30 percent of NIR light incident on the light absorption film and transmits less than 40 percent of visible light and greater than 70 percent of NIR light through the light absorption film. The camera captures image data representative of NIR light emitted through the reflective element and reflected from the interior cabin of the vehicle back through the reflective element.

First claim

The invention claimed is:

1. A vehicular cabin monitoring system, the vehicular cabin monitoring system comprising:
an interior rearview mirror assembly comprising a mirror head attached to and adjustable about a mounting structure, wherein the mounting structure is configured to attach at an interior portion of a vehicle equipped with the interior rearview mirror assembly;
wherein the mirror head accommodates a mirror reflective element;
wherein the mirror reflective element comprises (i) a planar glass substrate, (ii) a transflective mirror reflector disposed at a surface of the planar glass substrate and (iii) a light absorption film;
wherein the light absorption film comprises a polarizer film;
a camera accommodated by the mirror head and operable to capture image data;
wherein the camera views through (i) the planar glass substrate, (ii) the transflective mirror reflector and (iii) the light absorption film;
a light emitter accommodated by the mirror head and electrically operable to emit near infrared (NIR) light;
wherein the light emitter, when electrically operated, emits NIR light that passes through (i) the planar glass substrate, (ii) the transflective mirror reflector and (iii) the light absorption film;
an electronic control unit (ECU) having electronic circuitry and associated software, wherein the electronic circuitry includes an image processor for processing image data captured by the camera;
wherein the light absorption film (i) attenuates greater than 60 percent of visible light that is incident on the light absorption film and transmits less than 40 percent of visible light through the light absorption film and (ii) attenuates less than 30 percent of NIR light that is incident on the light absorption film and transmits greater than 70 percent of NIR light through the light absorption film;
wherein, with the mounting structure attached at the interior portion of the vehicle and when the light emitter is electrically operated to emit NIR light, the camera captures image data representative of NIR light that is emitted by the light emitter and passes through the (i) the planar glass substrate, (ii) the transflective mirror reflector and (iii) the light absorption film and that is reflected back from within an interior cabin of the vehicle and passes back through the (i) the planar glass substrate, (ii) the transflective mirror reflector and (iii) the light absorption film to be incident at the camera; and
wherein, via processing at the ECU of image data captured by the camera, the vehicular cabin monitoring system at least one selected from the group consisting of (i) detects an occupant present within the interior cabin of the vehicle and (ii) monitors the occupant present within the interior cabin of the vehicle.

2. The vehicular cabin monitoring system of claim 1 , wherein the polarizer film comprises a linear polarizer film having an axis of optical transmission.

3. The vehicular cabin monitoring system of claim 1 , wherein the light absorption film comprises (i) a first linear polarizer film having a first axis of optical transmission and (ii) a second linear polarizer film having a second axis of optical transmission.

4. The vehicular cabin monitoring system of claim 3 , wherein the first axis of optical transmission of the first linear polarizer film is parallel relative to the second axis of optical transmission of the second linear polarizer film.

5. The vehicular cabin monitoring system of claim 3 , wherein the first axis of optical transmission of the first linear polarizer film is perpendicular relative to the second axis of optical transmission of the second linear polarizer film.

6. The vehicular cabin monitoring system of claim 3 , wherein the first axis of optical transmission of the first linear polarizer film is at an oblique angle relative to the second axis of optical transmission of the second linear polarizer film.

7. The vehicular cabin monitoring system of claim 6 , wherein the first linear polarizer film attenuates greater than 50 percent of visible light that is incident on the first linear polarizer film, and wherein the second linear polarizer film attenuates greater than 50 percent of visible light that is incident on the second linear polarizer film.

8. The vehicular cabin monitoring system of claim 7 , wherein, with the first axis of optical transmission of the first linear polarizer film at the oblique angle relative to the second axis of optical transmission of the second linear polarizer film, the light absorption film (i) attenuates greater than 70 percent of visible light that is incident on the light absorption film and transmits less than 30 percent of visible light through the light absorption film and (ii) attenuates less than 20 percent of NIR light that is incident on the light absorption film and transmits greater than 80 percent of NIR light through the light absorption film.

9. The vehicular cabin monitoring system of claim 1 , wherein the polarizer film comprises a circular polarizer film.

10. The vehicular cabin monitoring system of claim 1 , wherein the polarizer film comprises at least one selected from the group consisting of (i) an iodine type polarizer film and (ii) a dye type polarizer film.

11. The vehicular cabin monitoring system of claim 1 , wherein the light absorption film is disposed at a display screen of the mirror reflective element.

12. The vehicular cabin monitoring system of claim 1 , wherein the light absorption film (i) attenuates greater than 70 percent of visible light that is incident on the light absorption film and transmits less than 30 percent of visible light through the light absorption film and (ii) attenuates less than 15 percent of NIR light that is incident on the light absorption film and transmits greater than 85 percent of NIR light through the light absorption film.

13. The vehicular cabin monitoring system of claim 1 , wherein the light absorption film attenuates less than 10 percent of NIR light that is incident on the light absorption film and transmits greater than 90 percent of NIR light through the light absorption film.

14. The vehicular cabin monitoring system of claim 1 , wherein, with the mounting structure attached at the interior portion of the vehicle, the camera captures image data representative of visible light reflected from objects within the interior cabin of the vehicle.

15. The vehicular cabin monitoring system of claim 1 , wherein the mirror reflective element comprises an electrochromic mirror reflective element.

16. The vehicular cabin monitoring system of claim 1 , wherein the mirror reflective element comprises a prismatic mirror reflective element.

17. The vehicular cabin monitoring system of claim 1 , wherein the mirror head accommodates a video display screen, and wherein the camera views through the video display screen.

18. The vehicular cabin monitoring system of claim 17 , wherein the light emitter emits NIR light that passes through the video display screen.

19. The vehicular cabin monitoring system of claim 1 , wherein, via processing at the ECU of image data captured by the camera, the vehicular cabin monitoring system monitors the occupant present within the interior cabin of the vehicle, and wherein the occupant is a driver of the vehicle and the vehicular cabin monitoring system determines at least one selected from the group consisting of (i) drowsiness of the driver of the vehicle, (ii) attentiveness of the driver of the vehicle and (iii) eye gaze direction of the driver of the vehicle.

Assignees

• Magna Mirrors Of America Inc

Inventors

• Larson Mark L
• Uken John T

Classifications

• B60R1/1207

  with lamps; with turn indicators · CPC title

• B60R2001/1253

  with cameras, video cameras or video screens · CPC title

• H04N23/57 Primary

  Mechanical or electrical details of cameras or camera modules specially adapted for being embedded in other devices · CPC title

• H04N23/21

  from near infrared [NIR] radiation · CPC title

• G02B5/3025

  Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state (G02B5/3008, G02B5/3016 take precedence) · CPC title