JP6259999B2 - Camera-integrated lighting system - Google Patents

Description

The present invention relates to a configuration structure of an LED lighting device using an LED (light emitting diode) as a light source.

  Imaging cameras are being installed in various places to improve photography, security, and safety. There is a need for a compact, space-saving design that integrates well with lighting.

  A conventional camera-integrated illumination device 100 will be described with reference to FIG. In FIG. 7, a camera-integrated illumination device 100 includes a light emitting device 201, an imaging device 101 such as an optical lens and an image sensor, and a substrate 301 that holds and fixes them and has wiring.

  The light emitting device 201 is composed of a plurality of LEDs that respectively emit light in the three primary colors of light. More specifically, it comprises a plurality of LEDs that emit red light, a plurality of LEDs that emit green light, and a plurality of LEDs that emit blue light. The size of the substrate 301 is, for example, a small substrate of about 2 cm × 1 cm.

  The camera-integrated illumination device 100 can be used for various portable devices such as a mobile phone or a PDA, and can eliminate the inconvenience of externally attaching the light emitting device 201 during imaging in a dark place. .

JP 2004-274492 A

  However, in the illumination device of Patent Document 1, the imaging device and the light emitting device are not coaxial, and the lens surface of the imaging device is visible from the outside. No matter how small, the camera cannot be hidden in the product design.

  An object of the present application is to capture an image with an imaging device without being noticed by a person in an illumination apparatus having the imaging device.

  In order to solve the above problems, a light guide plate that guides light from a light source by total reflection, the light source located at an end surface of the light guide plate, and an image pickup device having an imaging range facing the light emitting surface of the light guide plate; A camera-integrated illumination device is used.

  With the configuration and control described above, it is possible to provide a camera-integrated illumination device that can capture an image of the human eye without observing the camera or the lens in a state of light emission.

(A) Cross-sectional view showing the camera-integrated illumination device of the first embodiment, (b) Front view showing the camera-integrated illumination device of the first embodiment, (c) Perspective view of (a). (A) Partial enlarged sectional view of a groove portion of the light guide plate of the first embodiment, (b) a plan view of a pixel of the camera of the first embodiment, and (c) included in a flat portion of the light guide plate of the first embodiment. Diagram showing the relationship between the number of pixels and the transparency of the light guide plate (A) Sectional drawing which shows illuminating device of Embodiment 2, (b) Plan view of inner surface of light guide plate of illuminating device of Embodiment 2. The perspective view of the groove | channel of the light-guide plate of Embodiment 3. Sectional drawing of the groove | channel of the light-guide plate of Embodiment 4. (A)-(b) Sectional drawing of the recessed part of the light-guide plate of Embodiment 5, (c) The figure which shows distribution of the recessed part of (a) A perspective view showing a conventional camera-integrated illumination device

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
A camera-integrated illumination device according to Embodiment 1 of the present invention will be described with reference to FIGS.

  FIG. 1A is a cross-sectional view showing the camera-integrated illumination device 10 according to the first embodiment. FIG. 1B is a front view of the camera-integrated illumination device 10, and the camera 3 is covered with the light guide plate 1. The broken line in FIG. 1 (b) shows the position of each component in the covered state. FIG. 1C is a perspective view of the camera-integrated illumination device 10 according to the first embodiment.

As shown in FIG. 1A, the configuration of the camera-integrated illumination device 10 includes a light guide plate 1, a light source 2, a substrate 4, and a triangular groove 5. The camera 3 is installed on the side of the light guide plate 1 on which the triangular groove 5 is formed.
<Light guide plate 1>
As shown in FIG. 1A, the light guide plate 1 transmits light from the light source 2 to the light emitting surface 30 of the light guide plate 1. Therefore, the curved surface part is formed with a curvature with total reflection so that light does not leak. A triangular groove 5 is formed inside the light emitting surface 30. Light is emitted to the outside through the groove 5.

  The groove 5 has a triangular prism shape, and, as an example, the pitch is 250 μm, the groove width is 15 μm or less, and the rising angle is 52 °. Details of the angle will be described later. The groove 5 is formed so that a photographed image can be clearly confirmed by human eyes even when the camera 3 takes an image through the groove 5. The groove 5 will also be described in detail later. The material of the light guide plate 1 is a molded product of a transparent acrylic material.

  As shown in FIG. 1C, the light guide plate 1 has a shape similar to a half of a hollow cylinder. Some are flat. Opening portions at both ends may be open or closed.

Since the light guide plate 1 is not spherical but cylindrical, it is easy to ensure the flatness of the light emitting surface 30.
<Light source 2>
The light source 2 uses an LED light source. As shown in FIG. 1A, the light guide plate 1 is located at one end. One end is sufficient, but it may be provided at both ends. Since it exists in the edge part of the light-guide plate 1, there is little influence on the imaging of the camera 3. FIG.

<Camera 3>
The camera 3 is provided on the inner side and the rear side of the light emitting surface 30 of the light guide plate 1. The imaging surface of the camera 3 faces the light emitting surface 30 and is positioned in parallel. For example, a digital camera is used as the camera 3 and the number of pixels is 659 × 494 and the lens size is 6.2 mm × 4.3 mm. The size of one pixel is about 9 μm.

  As the lens of the camera 3, for example, a lens with a magnification such that the pixel size is about three times on the light guide plate 1 is used. The image size will be described later.

<Substrate 4>
On the substrate 4, the LED of the light source 2 is mounted. A rectangular plate having a thickness of 1 mm is formed with a circuit pattern for causing the light source 2 to emit light.

<Relationship between Pixel of Camera 3 and Groove 5>
The relationship between the pixels of the camera 3 and the grooves 5 will be described with reference to FIGS.

  FIG. 2A is a partial enlarged cross-sectional view of the groove 5 portion of the light guide plate 1. In FIG. 2A, in the groove 5, the light transmitted through the light guide plate 1 is reflected upward (outside) by the groove 5. Therefore, this portion is a portion that shines. A flat portion A (length a) obtained by subtracting the groove width H from the groove pitch T of the groove 5 is a portion through which light is transmitted.

  FIG. 2B is a plan view of the pixels of the camera 3. As shown in FIG. 2B, one pixel of the camera 3 is a square with one side D. Overall, they are a vertical LD2 and a horizontal LD1. When the pixel is rectangular, the following contents are applied based on the short side.

  This pixel is enlarged as the distance from the camera 3 increases. At the light guide plate 1, one side is kD, where k is a coefficient. In this situation, an image captured by the camera 3 is affected by how many pixels (one side is kD) included in the flat portion A.

FIG. 2C is a diagram illustrating the relationship between the number of pixels included in the flat portion A of the light guide plate 1 and the transparency of the light guide plate 1. FIG. 2C shows the relationship between the number of pixels in the flat portion A and the transparency of the light guide plate 1. The horizontal axis represents a value (a / kD) obtained by dividing the flat portion A by the enlarged pixel size kD at the light guide plate 1.
If this value is large, the number of pixels in one flat portion A increases.

  The vertical axis represents the level evaluation of the image of the camera 3 visually as the transparency. When the transparency is high, the light guide plate 1 is transparent, and the camera 3 can be seen from the outside through the light guide plate 1. If the transparency is low, the captured image is affected.

As a result, from FIG. 2C, this (a / kD) value is preferably larger than 2 and smaller than 26.
As a result, the following Expression 1 is obtained.

2 <a / kD <26 (Equation 1)
When the value is 2 or less, that is, when the flat portion A has fewer than two pixels, a groove is necessarily included in one pixel, and the transparency is very poor. The captured image of the camera 3 is dirty and difficult to recognize.
On the other hand, when the value is 26 or more, it exceeds 4%, the transparency is high, and the inside can be seen even if the light guide plate 1 is illuminated with light. The presence of the camera 3 can be seen from the outside through the light guide plate 1.

<Control>
In this configuration, the light source 2 emits light while being turned on and off (on / off). The imaging timing of the camera 3 captures an image when the light source 2 is OFF. ON and OFF are preferably turned on and off at a frequency of 72 Hz or higher so that they cannot be recognized by human eyes. This is because a person is unaware that it is blinking.

<Effect>
With the structure of the first embodiment, a person can take an image with the internal camera 3 when he recognizes that the light guide plate 1 is in a light emitting state. Since the camera 3 is not visible, imaging cannot be noticed.

(Embodiment 2)
The second embodiment will be described with reference to FIGS. 3 (a) and 3 (b). FIG. 3A is a cross-sectional view showing the camera-integrated illumination device 10 according to the second embodiment of the present invention. FIG. 3B is a plan view of the inner surface (camera 3 side) of the light guide plate 1 of the camera-integrated illumination device 10.

  The light guide plate 1 has a light emitting surface 30 and is provided with a groove 5. The area of the light emitting surface 30 includes a camera area 3a that is an imaging range of the camera 3 and a camera area outside 3b that is outside the imaging range.

As described in the first embodiment, the groove 5 in the camera region 3a only needs to have the relationship of Expression 1.
On the other hand, for the groove 5 outside the camera area 3b, the following equation 2 is preferable.
a / kD <26 (Formula 2)
The reason for this is that the higher the transparency, the better outside the camera area 3b, in an area unrelated to the imaging of the camera 3. However, since the camera 3 should not be visible from the outside, the value of a / kD needs to be smaller than 26 as in the first embodiment. As a result, the brightness can be improved without reducing the image captured by the camera 3.

(Embodiment 3)
The third embodiment is an example in which the groove 5 of the first embodiment is partially changed. The parts not described are the same as in the first and second embodiments.

FIG. 4 is an enlarged cross-sectional view of the triangular groove 5 portion of the third embodiment. The light guide plate 1 has two types of triangular grooves 5a and 5b. The two angles θ1 and θ2 are changed. The two types of grooves 5 a and 5 b are formed in the light guide plate 1. The range of the angle θ1 is Equation 3 below.
14 ° <θ1 <52 ° (Equation 3)
At the angle θ1, the direction in which light is reflected is greatly affected. The light path is indicated by the dotted line in FIG.
By controlling the angle θ1, the light crosses and is dispersed in two opposite directions. Thus, the internal camera 3 cannot be seen from the outside, and the video of the camera 3 becomes clearer.

  The reason why the angle θ1 is larger than 14 ° is as follows. When the angle is 14 °, the light travels through the light guide plate 1 by total reflection, and the light does not go outside. When the angle is larger than 14 °, the light is reflected to the outside.

  The reason why the angle θ1 is smaller than 52 ° is as follows. Since the angle is 52 ° and the light travels in the vertical direction, light is not dispersed. When the angle is 52 ° or more, the light is reflected in the direction in which the light has traveled.

  The two types of grooves 5a and 5b are preferably arranged in pairs as shown in FIG. However, they need not be adjacent to each other and may be a combination of two pieces or a combination of several pieces. The same number may be arranged at random. However, if there is a difference in number, it becomes non-uniform, so the number of each must be within a difference of no more than 10%.

  The apex angle is preferably about 90 ° from the viewpoint of forming the groove 5, that is, securing the depth of the groove 5 and securing the pitch of the groove 5. As a result, θ2 is preferably in the range of the following formula 4 from the formula 3.

38 ° <θ2 <76 ° (Formula 4)
(Embodiment 4)
The grooves 5a and 5b of the fourth embodiment are shown in FIG. FIG. 5 is a diagram corresponding to FIG. This is an example in which the angle θ <b> 1 of the third embodiment is changed in each groove 5. The parts not described are the same as those in the third embodiment. In FIG. 5, there are triangular grooves 5c, 5d, 5e, and 5f. In this example, there are a plurality of types of grooves, and four types of grooves are shown. The angles in the case of 2n types are θ11, θ12,... Θ1n, θ21, θ22,. In this case, the angle range is preferably the following formula 5.

Σ | θn1−θn2 | / n ≦ 38 ° (Formula 5)
The reason for the angle 38 ° is the difference between the upper limit and the lower limit in Equation 3, that is, 38 ° obtained by subtracting 14 ° from 52 °. In other words, referring to FIG. 5, the average difference between the two left angles θ21 and θ22 and the two right angles θ11 and θ12 is within 38 °. In this case, n is 1 or 2.

  Here, θ11, θ12,... Θ1n, θ21, θ22... Θ2n are θ1, and follow Equation 3.

  By setting the above angle, the target light distribution is controlled, and the camera is difficult to see from various directions.

(Embodiment 5)
FIG. 6A and FIG. 6B are perspective views of a recess 11 of a modification of the groove 5 of the first to fourth embodiments. These are a truncated cone-shaped recess 11 and an oblique truncated cone-shaped recess 14. Unlike the groove 5 of the first to fourth embodiments, it is a dot-shaped recess. There are multiple points.

  The distribution is shown in a plan view of the light guide plate 1 in FIG. They are arranged in a honeycomb shape. The light strikes one of the recesses 11.

  The angles θ, θ1, and θ2 are in the same angle range as in the above embodiment. The angle is an angle with respect to the direction in which light is transmitted through the light guide plate 1.

  In contrast to the conditions for the triangular prismatic grooves of the first to fourth embodiments, in this dot-shaped recess, the average length between the recesses (length a of the flat portion A) and the average distance between the recesses (groove pitch T) To establish.

  As a result, it is possible to obtain a light emission pattern that is less likely to cause luminance unevenness.

(Note)
Each of the above embodiments can be combined. There may be a plurality of types of recesses 11.

It can be used as a camera-integrated lighting device in the security field, headlights, etc.

DESCRIPTION OF SYMBOLS 1 Light guide plate 2 Light source 3 Camera 3a Camera area 3b Outside camera area 4 Substrate 5 Groove 5a Groove 5b Groove 5c Groove A Flat part D One side H Groove width T Groove pitch 10 Camera integrated illumination device 11 Recess 14 Recess 30 Light emitting surface 100 Camera Integrated lighting device 101 Imaging device 201 Light emitting device 301 Substrate LD1 Horizontal LD2 Vertical

Claims (6)

A light guide plate that guides light from the light source by total reflection;
The light source located on the end face of the light guide plate;
An imager having an imaging range facing the light emitting surface of the light guide plate;
Including
The light guide plate has a triangular prism or a concave groove on the light emitting surface, the pitch of the groove is T, the width of the groove is H, the width of the pixel of the image pickup device is D, and the guide of the image pickup device is. A camera-integrated illumination device represented by the following formula, where k is the magnification at the position of the light plate .
2 <(TH) / kD <26 The light emitting surface of the light guide plate includes the imaging range and a non-imaging range outside the imaging range,
Wherein the grooves of the non-imaging range, camera-integrated lighting device according to claim 1, wherein according to the following equation.
(TH) / kD <26 3. The camera-integrated illumination device according to claim 1, wherein a smaller rising angle of the groove is θ < b > 1 and a larger rising angle is θ < b > 2 , according to the following formula.
14 ° <θ1 <52 °, 38 ° <θ2 <76 ° 4. The camera-integrated illumination device according to claim 3 , wherein the groove is composed of a plurality of n types, wherein θn <b> 1 is the smaller rising angle and θn <b> 2 is the larger rising angle.
Σ | θn1−θn2 | / n ≦ 38 ° And enters the cut of the light source, the camera built-in type lighting device according to any one of claims 1 to 4, characterized in that to synchronize the imaging OFF and ON of the imager. The frequency of turning on and off the light source is 72 Hz or more,
The camera-integrated illumination device according to claim 5 , wherein an image is picked up by the image pickup device when the light source is turned off.

Images