JP2001154612A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device in which the light from a light source refracted and/or reflected in each minute optical element of an optical device can be made to exit from the optical device accurately in the direction to the viewing point range where the viewing points of an observer are present, and in which the light emitted by the light source can be efficiently made to enter each minute optical element. SOLUTION: In the display device 31, when the light 11 from a light source 5 passes an optical device 3, the light is refracted and/or reflected on the circumference faces 9a, 9b of each minute optical element 9 to produce a pointer image extending in the radial direction. The inclination angles of the circumference faces 9a, 9b in the outer and inner circumference sides, respectively, of each minute optical element 9 to the normal line direction B of the optical device 3 are controlled in such a manner that the exiting direction of the light exiting from the front face of the optical device 3 is in a specified viewing point range where the viewing points of an observer are present. A plurality of the minute optical elements 9 are arranged in steps so that the light 11 from the light source 5 can enter each minute optical element 9 without hindered by other minute optical elements 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device for optically generating a pseudo pointer.

[0002]

2. Description of the Related Art In general, in a conventional display device, a pointer is mechanically rotated to display a vehicle speed or the like.

[0003]

However, the conventional display device requires a complicated driving mechanism for rotating the hands, and has a problem that the device configuration is complicated.

<Proposal Example> Therefore, the inventors of the present application have proposed a display device shown in FIGS. The display device 1 includes an optical element 3, a plurality of light sources 5 disposed on an outer peripheral portion on the back side of the optical element 3,
A dial display section (not shown) for displaying the dial 7 is provided. 6 indicates the central axis of the optical element 3.

As shown in FIGS. 5 and 6, the optical element 3 is a plate-like member entirely formed of a translucent material, and has two outer peripheral surfaces intersecting in a chevron shape on the rear surface. 9
A plurality of ridge-shaped micro optical elements 9 having a and 9b are formed concentrically and periodically in the radial direction so as to be connected in parallel with each other in the circumferential direction. Here, each micro optical element 9
Of the two outer peripheral surfaces 9a and 9b, the outer peripheral surface 9a on the outer peripheral side
Function as an incident surface for receiving the light 11 from each light source 5, and the outer peripheral surface 9 b on the inner peripheral side functions as a reflecting surface for reflecting the light 11 incident from the outer peripheral surface 9 a to the front side of the optical element 3. I have.

[0006] As shown in FIGS. 5 and 6, the plurality of light sources 5 are provided at the outer peripheral portion on the rear surface side of the optical element 3.
The micro optical elements 9 are regularly arranged along a circumferential direction in which the micro optical elements 9 extend at a position separated by a predetermined distance from.

When the light 11 from each light source 5 passes through the optical element 3 from the back side to the front side, the light 11 is refracted and reflected by the outer peripheral surfaces 9a and 9b of each micro optical element 9 of the optical element 3, Light 1 emitted from the front side of the optical element 5
1, each light source 5 turned on from the center of curvature of the plurality of micro optical elements 9 (here, the center of the optical element 3).
Pointer image (light ray image) 1 elongated in the radial direction corresponding to
5 is generated at the image forming position 16.

Each light source 5 can be individually turned on and off, and a predetermined quantity of a quantity is assigned to each light source 5 and the light source 5 corresponding to the quantity is selectively turned on. By doing so, the pointer image 15 indicating the quantity value is displayed. Thus, analog quantity display can be performed without using a conventional mechanical configuration.

The display device 1 configured as described above is installed on an instrument panel 17 of a vehicle, for example, as shown in FIG. 7, and is used for displaying various quantities such as a vehicle speed and an engine speed. It has become.

<Problems of Proposed Example> However, the above-described display device 1 has the following problems.

First, the outer peripheral surface 9a of each micro optical element 9,
9b: normal direction of the optical element 3 (direction parallel to the central axis A)
Since the inclination angle with respect to B is not set properly,
As shown in FIG. 8, a part of the light 11 refracted and reflected by the outer peripheral surfaces 9a and 9b of each micro optical element 9 is directed to the outside of a viewpoint range (eye range) 21 where a viewer's viewpoint can exist. And is emitted.

Here, in practice, the eye range 21 is set at a predetermined area (in this case, about 700 mm) D away from the optical element 3 along the central axis A on the front side with a predetermined area. However, here, the emission angle when the light 11 is emitted from each point on the front surface of the optical element 3 is within a predetermined angle range (here, the inner peripheral side and the normal direction B at that point are the center). (In the range of 6 ° on the outer peripheral side), the emitted light 11 is emitted toward the inside of the eye range 21.

In the example of FIG. 8, each micro optical element 9 is refracted,
Since the reflected light 11 is deviated to the inner peripheral side from the normal direction B, the reflected light 11 forms the inner peripheral side portion of the pointer image 15 as shown in FIG. 11 does not reach the eye range 21, and the portion on the inner peripheral side of the pointer image 15 has become dark or has disappeared. FIG. 9B is a diagram showing an ideal pointer image displayed with high luminance and uniform luminance in the longitudinal direction.

Second, since each micro optical element 9 is arranged in a plane in the radial direction, when the light 11 from the light source 5 enters each micro optical element 9, the micro optical element 9 on the inner peripheral side is used. The element 9 is shaded by the adjacent small optical element 9 on the outer peripheral side,
The light 11 emitted from the light source 5 cannot be efficiently incident on each micro optical element 9, and the amount of light 11 incident on each micro optical element 9 becomes small. There is a problem that the brightness of the image 15 is reduced.

In view of the above problems, the first aspect of the present invention
An object of the present invention is to provide a display device capable of accurately emitting light from a light source, which is refracted and reflected by each micro optical element, from an optical element toward a viewpoint range where a viewer's viewpoint can exist. is there.

A second object of the present invention is to provide a display device capable of efficiently causing light emitted from a light source to enter each micro optical element.

[0017]

The technical means for achieving the above object is that a plurality of ridge-shaped micro-optical elements each having two outer peripheral surfaces intersecting substantially in a mountain shape are parallel to each other in the circumferential direction on the back side. And a substantially plate-shaped optical element periodically formed in the radial direction, and at least one light source that irradiates predetermined light toward the plurality of micro optical elements from the outer peripheral portion on the back surface side of the optical element, Irradiating from the light source, entering the micro optics through the outer peripheral surface on the outer peripheral side of each of the micro optical elements, and being reflected by the outer peripheral surface on the inner peripheral side of each of the micro optical elements, the optical element A display device configured to generate, by the light emitted from the front side of the optical element, a light ray image extending from a center of curvature of the plurality of micro optical elements of the optical element toward a radiation direction corresponding to the light source. ,
Inclination angles (a) of the outer peripheral surface on the outer peripheral side and the inner peripheral side of each of the micro optical elements with respect to the normal direction of the optical element,
(B) is individually set for each of the micro-optical elements so that the emission direction when the light is emitted from the front side of the optical element is within a predetermined viewpoint range where a viewer's viewpoint can exist. It is characterized by being performed.

Preferably, the arrangement positions of the outer peripheral surfaces of the plurality of micro optical elements are gradually shifted to the rear side in the normal direction in a field-like manner as the micro optical elements are positioned closer to the inner peripheral side. Good.

[0019]

FIG. 1 is a sectional view showing a partial configuration of a display device according to an embodiment of the present invention. In the display device 31 according to the present embodiment, the aforementioned FIGS.
The same reference numerals are given to the portions corresponding to the display device 1 shown in FIG.

In this display device 31, as shown in FIG. 1, the positions of the outer peripheral surfaces 9a and 9b of the plurality of micro optical elements 9 are set such that the closer the inner micro optical element 9 is, the more the normal optical direction , And the degree of shadow of each micro optical element 9 with respect to other micro optical elements 9 can be greatly improved. As a result, the light source 5
The light 11 from the light source is efficiently and uniformly incident on the outer peripheral surface 9 on the outer peripheral side of each micro optical element 9.

Further, in the display device 31, the inclination angles a and b of the outer peripheral surfaces 9a and 9b of each micro optical element 9 with respect to the normal direction B are set as shown in FIG. 3 is set so that the emission direction when the light is emitted from the front side is within the eye range 21.

Referring to FIG. 2, a method of setting the inclination angles a and b of the outer peripheral surfaces 9a and 9b of each micro optical element 9 will be described.
First, the definitions of various parameters in FIG. 2 will be described. Parameters a and b indicate the inclination angles of both outer peripheral surfaces 9 a and 9 b of each micro optical element 9 with respect to the normal direction B of the optical element 3. Here, a is defined with a sign that the counterclockwise direction with respect to the normal direction B is positive, and b
Is defined as positive in the clockwise direction with respect to the normal direction B. Here, for convenience of explanation, the cross section along the radial direction of both outer peripheral surfaces 9a and 9b will be described as a straight line, but actually, the cross sectional shape of at least one of both outer peripheral surfaces 9a and 9b will be described. In order to prevent light 11 refracted and reflected by each micro optical element 9 from being dispersed evenly in the eye range 21 and to prevent a point where the pointer image 15 cannot be visually recognized in the eye range 21, the light 11 is projected outward. Preferably, it is appropriately curved.

The parameter θ indicates the irradiation angle of the light 11 incident on the outer peripheral surface 9a of each micro optical element 9 with respect to the normal direction B when the light 11 is irradiated from the light source 5, and is clockwise with respect to the normal direction B. The sign is defined as positive. Parameter α
Indicates the angle of incidence of the light 11 on the outer peripheral surface 9a,
Are defined as positive in the counterclockwise direction with respect to the outward normal direction. The parameter α ′ is the outer peripheral surface 9 of the light 11
The sign indicates the refraction angle at a, and the sign is defined as positive with respect to the inward normal direction of the outer peripheral surface 9a. The parameter β indicates a reflection angle on the outer peripheral surface 9b, and the outer peripheral surface 9b
The sign is defined as positive in the counterclockwise direction with respect to the inward normal direction. The parameter γ is such that the light 11 is
Indicates the angle (emission angle) between the emission direction and the normal direction B when the light is emitted from the front side of the light emitting device, and the sign is defined as positive in the counterclockwise direction with respect to the normal direction B.

Next, a relational expression to be satisfied by the inclination angles a and b is derived under the above-mentioned parameter setting. First, the following relational expression holds for ２ABC in FIG.

[0025]

(Equation 1)

If the refractive index of the optical element 3 is n (here, 1.49), the relationship between the incident angle α and the refraction angle α ′ is

[0027]

(Equation 2)

When this is rearranged for α ′,
It looks like this:

[0029]

(Equation 3)

Further, the following relational expression holds for △ BDE.

[0031]

(Equation 4)

The following relational expression holds for GEF.

[0033]

(Equation 5)

From the above equations, when β is eliminated from the equations,

[0035]

(Equation 6)

When this is arranged for b, the relational expression to be obtained is obtained as follows.

[0037]

(Equation 7)

Here, since the irradiation angle θ is determined in advance by the positional relationship between the light source 5 and each of the micro optical elements 9, the emission angle γ is determined by the equation Range (here -6 ° to +6
When set to (°), it can be seen that the parameter having the degree of freedom of setting is one of a and b. In other words, in each of the micro optical elements 9, under the condition of the given irradiation angle θ, based on the relational expression, the two outer peripheral surfaces 9a, 9a are set so that the emission angle γ is within the predetermined eye range 21. It can be seen that the inclination angles a and b of 9 b may be set individually for each micro optical element 9.

In this embodiment, each micro optical element 9
The light 11 refracted and reflected by the two outer peripheral surfaces 9a and 9b travels substantially parallel to the normal direction B and enters the front surface of the optical element 3 at a small incident angle. We have been ignoring the effect of refraction at
In the case where a more strict discussion is performed, or when the angle of incidence of the light 11 on the front surface of the optical element 3 is set to be relatively large, the influence of refraction on the front surface is considered. We need to discuss.

By the way, in the optical element 3 according to the present embodiment, the inclination angle a of the outer peripheral surface 9a on the outer peripheral side of each micro optical element 9 is set.
It has been found that the following inconvenience may occur when is set to zero. That is, when the inclination angle a of the outer peripheral surface 9a is set to zero, both outer peripheral surfaces 9a,
9b, the angle of incidence of the light 11 refracted and reflected on the front surface of the optical element 3 increases, and the light 11 is totally reflected without transmitting through the front surface, and again the other micro optical element 9
It has been found that the light beams enter the outer peripheral surfaces 9a and 9b of the light emitting device and generate an unnecessary light beam image. Therefore, the inclination angle a of each outer peripheral surface 9a on the outer peripheral side is set within a predetermined range larger than zero (here, within a range of 10 ° to 40 °) (here, set at 35 °). ing).

Therefore, in this embodiment, since the inclination angle a of each outer peripheral surface 9a is set to 35 °, when the irradiation angle θ is determined, the possible range of the inclination angle b of each outer peripheral surface 9b is , The emission angle γ is uniquely determined within a range where the emission angle γ is within the eye range 21.

The following Tables 1 and 2 show that the emission angle γ has the upper limit (+ 6 °) and the lower limit (−6 °) of the eye range 21.
The value of the inclination angle b of the outer peripheral surface 9b with respect to each value of the irradiation angle θ when the angle is set to is shown. Here, the refractive index n
Is set to 1.49, and the inclination angle a of each outer peripheral surface 9a is set to 35 °.

[0043]

[Table 1]

[0044]

[Table 2]

When the values of the inclination angle b shown in Tables 1 and 2 are plotted on a graph with the horizontal axis θ and the vertical axis b, graphs G1 and G2 as shown in FIG. 3 are obtained. Here, the graph G1 is a graph when γ = + 6 °, and the graph G1
2 is a graph when γ = −6 °. This graph G
1 and G2, for each value of the irradiation angle θ, the graph G1
The hatched area sandwiched by G2 is the outer peripheral surface 9
It can be seen that the inclination angle b of b is within a possible range. Therefore, when actually determining the inclination angle b of each outer peripheral surface 9b,
In the hatched area shown in the graph of FIG. 3, the inclination angle b may be determined so as to smoothly change between the adjacent micro optical elements 9.

As described above, the inclination angles a and b of the outer peripheral surfaces 9a and 9b of each micro optical element 9 are determined, so that each micro optical element 9 is refracted and reflected by each micro optical element 9 as shown in FIG. The light 11 from the light source 5 can be accurately emitted from the optical element 3 into the eye range 21 of the viewer, and as a result, the pointer image 15 can be uniformly and highly bright in the entire longitudinal direction. Can be displayed.

Also, both outer peripheral surfaces 9 of the plurality of micro optical elements 9
Since the arrangement positions of a and 9b are gradually shifted toward the rear side in the normal direction B toward the rear side in the normal direction B, the arrangement positions of the micro optical elements 9 are different from those of the other micro optical elements 9. The degree of shading can be greatly improved, and as a result, the light emitted from the light source 5 can be efficiently and uniformly supplied to each micro optical element without substantially shading other micro optical elements 9. The intensity of the pointer image 15 can be improved with respect to the amount of light emitted from the light source 5.

[0048]

According to the first aspect of the present invention, the inclination angles (a) and (b) of the outer peripheral surface on the outer peripheral side and the inner peripheral side of each micro optical element with respect to the normal direction of the optical element are determined by the light. Is set individually for each micro optical element so that the emission direction when the light is emitted from the front side of the optical element is within a predetermined viewpoint range where the viewpoint of the viewer can exist, so that each micro optical element The refracted and reflected light from the light source can be accurately emitted from the optical element toward the viewer's viewpoint range, and as a result, the pointer image has uniform brightness over the entire longitudinal direction and high brightness. Can be displayed.

According to the second aspect of the present invention, the arrangement positions of the two outer peripheral surfaces of the plurality of micro optical elements are shifted toward the rear side in the normal direction toward the inner peripheral side in a stepwise manner. That can significantly improve the degree to which each micro-optical element is shaded by other micro-optical elements,
The light emitted by the light source can be efficiently made incident on each micro optical element, and the brightness of the pointer image can be improved with respect to the light emission amount of the light source.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a partial configuration of a display device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram for deriving a relational expression to be satisfied by inclination angles a and b of both outer peripheral surfaces of each micro optical element.

FIG. 3 is a graph showing a possible range of a tilt angle b of an outer peripheral surface on an inner peripheral side with respect to each value of an irradiation angle θ.

FIG. 4 is a diagram showing how light from a light source is refracted and reflected by each micro optical element in the display device of FIG.

FIG. 5 is a front view of a display device according to a proposal example.

FIG. 6 is a sectional view showing a partial configuration of the display device of FIG. 5;

FIG. 7 is a front view showing an example of installation of the display device shown in FIGS. 1 and 5;

FIG. 8 is a view showing how light from a light source is refracted and reflected by each micro optical element in the display device of FIG. 5;

9A is a diagram showing a pointer image displayed by the display device of FIG. 5, and FIG. 9B is a diagram showing an ideal pointer image.

[Explanation of symbols]

 Reference Signs List 3 optical element 5 light source 9 micro optical element 9a outer peripheral surface on outer peripheral side 9b outer peripheral surface on inner peripheral side 15 pointer image 21 eye range a, b tilt angle B normal direction

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masayoshi Imoto 1-7-10 Kikuzumi, Minami-ku, Nagoya-shi, Aichi F-term in Harness Research Institute, Inc. (reference) 5C094 AA03 AA10 AA55 ED01 JA09 5G435 AA03 CC04

Claims (2)

[Claims] 1. A substantially plate-shaped optical element in which a plurality of ridge-shaped micro-optical elements having two outer peripheral surfaces intersecting in a substantially mountain shape are formed on a back surface side in parallel with each other in a circumferential direction and periodically in a radial direction. And at least one light source that irradiates predetermined light toward the plurality of micro optical elements from the outer peripheral part on the back side of the optical element, and is radiated from the light source, and is provided on the outer peripheral side of each of the micro optical elements. The light is incident on the micro optics through the outer peripheral surface, is reflected by the outer peripheral surface on the inner peripheral side of each of the micro optical elements, and is emitted from the front side of the optical element. A display device configured to generate a ray image extending from a center of curvature of a plurality of micro optical elements toward a radiation direction corresponding to the light source, wherein an outer periphery of each of the micro optical elements with respect to a normal direction of the optical element Side and inner side Inclination angle of the outer peripheral surface (a),
(B) is individually set for each of the micro-optical elements so that the emission direction when the light is emitted from the front side of the optical element is within a predetermined viewpoint range where a viewer's viewpoint can exist. A display device characterized by being performed. 2. The arrangement position of the two outer peripheral surfaces of the plurality of micro optical elements is shifted toward the rear side in the normal direction in a stepwise manner toward the inner side with respect to the micro optical elements. The display device according to claim 1.