JPS6333876A - Measuring method of luminance for led array - Google Patents

Abstract

PURPOSE:To measure luminance to all the elements of an LED array at a high speed by adjusting and setting the positions of the LED array and an image sensor, measuring the quantity of light received by each photodetector in each state of setting and computing the luminance on the basis of a maximum value of quantities of received light measured. CONSTITUTION:A photodetector for an image sensor 13 corresponding to a predetermined LED element is approximately positioned previously so as to receive light most efficiently. An LED array 11 is lit under the state of the positioning of the photodetector, and the positions of the LED array 11 and the image sensor 13 are adjusted and set once or more. The quantities of light reception acquired at every element for the image sensor 13 are measured under the state of setting, and the luminance of the LED element 11 is computed on the basis of the maximum quantity of light received in the quantities of light reception obtained by measurement at once or more. Accordingly, the luminance of the LED elements can be measured in a short time, thus mass-producing the LED arrays.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an LED array brightness measurement method for measuring the brightness of each LED element of an LED array.

BACKGROUND OF THE INVENTION FIG. 5 is a perspective view showing an LED array brightness measuring device to which an example of a conventional LED array brightness measuring method is applied.

In this LED array brightness measuring device, first, the stepping motor 3 is rotated until the light emitted from the most advanced LED element of the LED array 1 hits the light receiving surface of the photocentimeter 2, and the gear 4 is rotated.
, the photosenner 2 is moved in the direction of the arrow via the feed screw 5. -Then, only the most advanced LED element is caused to emit light, and this light is received by the photosensor 2 through the CellHoc lens array 6, and its brightness is measured. Next, only the LED elements adjacent to the LED elements measured as described above are caused to emit light, and the brightness thereof is measured using the photosensor 2 in the same manner as described above. Thereafter, similarly, the brightness of the LED elements is sequentially measured over the entire LED array 1. In addition, in such a brightness measurement process, as the LED element that emits light moves, the photo sensor 2 is moved at appropriate intervals in order to prevent the emitted light from hitting the light receiving surface of the photo sensor f2, making it impossible to measure. .

Problems to be Solved by the Invention However, with such a measurement method, it takes a very long time to measure the brightness of all the LED elements on the LED array 1, and as a result, it poses a major obstacle to the mass production of the LED array 1. It had become.

The above-mentioned problem arises for the following reasons. That is, firstly, since there is only one photo sensor, brightness measurement can be performed simultaneously using one L.
This can only be done for ED elements.

Second, as the brightness of each LED element is measured one after another, the light generated by the LED no longer hits the light receiving part of the photosensor, so it is necessary to correct the positional relationship between the LED element being measured and the photosensor each time. , you cannot move on to the next brightness measurement until the positional relationship is stabilized.

As a countermeasure for this, one-on-one connection with each LED element of the LED array is possible.
(It is conceivable to use a light-receiving element array with two pairs of windows, that is, a one-dimensional image sensor.By the way, even if the LED array and image sensor use the same element density,
Due to differences in manufacturing errors, temperature expansion, etc., it is difficult to match each LED element and light receiving element one-on-one (=facing each other), and this countermeasure was not an appropriate solution to the above problem.

The present invention was made in order to solve the above problems, and it is possible to measure the brightness of an LED element in a short time, and as a result, L
It is an object of the present invention to provide an LED array brightness measurement method that allows mass production of ED arrays.

Means for Solving the Problems In order to achieve the above object, the present invention changes the relative position of the LED array and image sensor using an LED array/image sensor relative position changing means while causing a predetermined LED element of the LED array to emit light. and the predetermined LED
The position of the LED array is roughly determined in advance so that the light-receiving element of the image sensor corresponding to the element receives light most efficiently, and while the LED array is turned on in this positioned state, the positional relationship between the LED array and the image sensor is adjusted.・1 with image sensor relative position changing means
The amount of light received by each element of the image sensor is measured in each setting state, and the brightness of the LED element is determined based on the maximum amount of light received among the one or more measured light amounts. It is characterized by calculating.

Operation First, the light receiving element of the image sensor corresponding to a predetermined LED element is roughly positioned in advance so that it receives light most efficiently. In this positioning state, turn on the LED array, and set the position of the LED array and image sensor to 1.
The amount of light received by each element of the image sensor is measured in this setting state, and the amount of light received by the LED element is determined based on the maximum amount of light received among the amounts of light received in one or more measurements. Calculate the brightness.

Embodiment FIG. 1 is a perspective view showing an LED array brightness measuring device to which an LED array brightness measuring method according to an embodiment of the present invention is applied.

This LED array brightness measuring device (hereinafter referred to as the brightness measuring device) is an LED array brightness measuring device in which a plurality of LED elements are arranged in a row.
It has an array 11 and an image sensor 13 that receives light emitted from the LED array 11 via a self-lock lens array (hereinafter referred to as SLA) 12, and has a 5LAI2 array.
and the image sensor 13 are held in the device main body (not shown), while the LED array 11 is
The LED array moving means 50 serving as image sensor relative position changing means moves the image sensor in the main scanning direction (indicated by arrow A), the sub-scanning direction (indicated by arrow B), and the rotational direction (indicated by arrow C). ing.

The LED array moving means 50 includes a first base part 51, a second base part 52, and a third base part 53 substantially on a pedestal, and these are mutually movable (stacked in 13 stages,
The LED array 11 is placed on the base portion 51.

A stepping motor 54 is provided in the main body of the apparatus, and a gear 56 is connected to the slapping motor 54 via a timing belt 55. This gear 56
is provided with a feed screw 57, and this feed screw 57
It is fitted into the base portion 53. As the feed screw 57 rotates as the stepping motor 540 rotates, the third base portion 53 moves in the sub-scanning direction (arrow B) with the second base portion 52, first base portion 51, and LED array 11 mounted thereon. Moving.

A stepping motor 5 is mounted on the side end portion of the third base portion 53.
8 and this stepping motor 58 (=interlocking gear 5
9 is placed. On the other hand, teeth that mesh with the gear 59 are arranged in a row on the side surface of the second base portion 52 .

Furthermore, a groove is formed in the bottom of the second base part 52 in the longitudinal direction (in the direction of arrow A), while a protrusion that fits into the groove is formed in the third base part 53. When the stepping motor 58 rotates, the second base portion 52 moves in the main scanning direction (arrow B) via the gear 59.

A stepping motor 6 is mounted on the side end portion of the second base portion 52.
0 and a gear 61 interlocked with this stepping motor 60.
is listed. On the other hand, the side end of the first base part 51 is provided with substantially arc-shaped teeth so as to mesh with the gear 61, and the first base part 51 on the opposite side is provided with a rotating shaft 61.
2 is pivotally supported by the second base portion 52. When the stepping motor 60 rotates, the first base portion 51 rotates in the direction of arrow C about the rotation shaft 62 with the LED array 11 mounted thereon via the gear 61.

Furthermore, the main body of the apparatus includes a stepping motor (hereinafter referred to as a motor) 54. 58. 60 rotation, lighting of any LED element of the LED array 11, image sensor 13
A controller (which stores and calculates the received light data of the
(not shown).

A method for measuring LED contrast brightness using the brightness measuring device configured as described above will be explained.

First, as a first step, the following work is performed to determine the positional relationship between the LED array 11 and the image sensor 13.

■ Move the motor 54 while keeping all the elements of the LED array 11 lit (Secondly (in the following explanation, items for moving the motors 54, 58, and 60 will be omitted)) Move the third base part 53 in the direction of arrow B. , and memorize the positions near both ends of the image sensor 13 where the received light output is maximum.

■ Based on this stored position information, the first base portion 51
is rotated in the direction of arrow C so that the light emitting line of the LED array 1 and the light receiving line of the image sensor 13 are set to be parallel.

■ Repeat steps (1) and (2) above to set the position where the parallelism is the best.

■ Turn on only the most advanced LED element of the LED array 11, search for the position where the light receiving output of the corresponding image sensor 13's light receiving element is maximum while moving the second base part 52 in the direction of arrow A, and locate the position ( The position α) is stored.

■ From the position α found in the above ■, turn on only the rearmost LED element of LED array] 1, and select the position where the light reception output of the corresponding image sensor 13 is maximum on the second base part 52.
Search for it while moving it in the direction of arrow A, and find its position (position β
) is memorized.

With the above operations, positioning before luminance measurement is completed.

Next, in the second step, the LED array 1 is installed using the following procedure.
Measure the brightness of 1. However, here the image sensor 13
The variation in sensitivity of each light-receiving element is corrected by a correction circuit provided in the above-described controller.

■ The resolution calculated from the relationship between the dimensional errors in the main scanning direction of the LED array 11 and the image sensor 13 is the resolution γ, and the second base portion 52 is moved from position α to position β for each resolution γ, and LED array 1
The light emission of the required LED element 1 is measured by the image sensor 13.

■ The resolution calculated from the relationship between the dimensional errors in the sub-scanning direction of the LED array 11 and the image sensor 13 is defined as the resolution θ, and the third base portion 53 is moved by the resolution θ within the vertical dimensional error range, and Measure in the same way as above.

From the brightness data measured in this way, the best value is extracted and used as regular brightness measurement data, and each LED
The data is proportional to the luminance of the element.

This will be explained in more detail using FIGS. 2 and 3.

FIG. 2 is a schematic diagram showing the light receiving state of the image sensor 13 corresponding to the above measurement method focusing on one LED element. FIG. 2(a) shows the LED element and the L
A light receiving element on the image sensor f13 corresponding to the ED element is shown. In the embodiment shown in this figure, the main scanning direction (X
The measurement was performed in 5 steps in the X direction (direction) and in 3 steps in the sub-scanning direction (X direction), resulting in measurement data being obtained 15 times. In FIG. 2(a), the rectangle (b) indicates the light-receiving element of the image sensor 13, and indicates that the white part of the mouth (which is illuminated by the LED elements (indicated by dotted circles) of the two-LED array 11). The second (b) is a list of the measured values in (a) of the same figure, and in this case, the measured value 98 corresponds to this LE.
This is used as the brightness of the D element.

FIG. 3 is a model of the difference in element density between the LED array 11 and the image sensor 13, both of which have the same element density.
In the figure, the rectangle (b) indicates the light receiving element of the image sensor 13, the circle (◯) indicates the LED element, and the white part in the mouth indicates the light irradiated by the LED element. Figures (a-1) and (a-2)
), the element density of the LED array 11 is the same as that of the image sensor 13.
This is an example in which the element density is slightly higher than that of , and (b-1) and (b-2) in the figure are the opposite. Also, the same figure (a-1)
and (b-1) show an example at the position α, and (a
-2) and (b-2) show examples at the position β.

In this case, as can be seen by comparing (b-1) and (b-2) in the same figure, the distance L from the position α to the position β is
When the relative positions of the ED array 11 and the image sensor 13 are moved, there is a possibility that light from an LBD element other than the LED element corresponding to an arbitrary light receiving element of the image sensor f13 may be irradiated onto this light receiving element. In such cases (below,
In this case (referred to as "case 1"), it is necessary to make the measurement by emitting light from the LED elements line by line at a predetermined interval on the LED array 11. Therefore, in this case, the luminance measurement for the above-mentioned items 1 to 2 is performed by emitting light from the LED elements at predetermined intervals.

As is clear from the above description, the present invention (two LED
In the array brightness measurement method, brightness can be measured most quickly when the number of elements and element density of the image sensor used for measurement are the same as the LED array that is the object to be measured.

However, the density and number of light-receiving elements of the image sensor are not limited thereto, and even when conditions such as "Case 1" exist, the measurement time is slower than the above, but the brightness measurement method of the present invention is applicable.

FIG. 4 is a perspective view showing another LED array brightness measuring device to which the LED array brightness measuring method of the above-described embodiment is applied. This LED array brightness measuring device is 5L in Figure 1.
A12, in place of the image sensor 13 (2, lens 81
A reduction optical system is constructed using the IC type image sensor 82 and the IC type image sensor 82. In the figure, 11 is an LED array similar to that shown in FIG. The structure other than the lens 81 and the IC type image sensor 82 is the same as that of the luminance measuring device shown in FIG.

In the above-mentioned embodiment, the case where the 5LA 12 is held in the main body of the device has been explained, but the LED array 11 (two pairs of windows may be provided and made movable with respect to the image sensor 13). good.

In addition, in the above embodiment, the image sensor is fixed and the LED
Although the case where the array is moved has been described, the arrangement may be made in the opposite manner.

Effects of the Invention As is clear from the above description, the LED array and the image sensor are approximately positioned in advance by emitting light from a predetermined LED element, and in this positioning state, the positions of the LED array and the image sensor are further adjusted/adjusted one or more times.
setting, the amount of light received by each light receiving element is measured in each setting state, and the brightness of the LED element is calculated based on the maximum amount of light received among the one or more measured amounts of light received. The number of times the LED element's light emission is switched, the number of times the light-receiving element moves, and the time it takes to move are significantly reduced, and the brightness of all elements of the LED array can be measured at high speed.As a result, the production efficiency and cost reduction of the LED array are dramatically improved. bring about.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an LED array brightness measuring device to which an LED array brightness measuring method according to an embodiment of the present invention is applied;
FIG. 2 is a schematic diagram for explaining the light reception output of an arbitrary LED element and an image sensor when one embodiment of the present invention is applied to the measuring device of FIG. 1, and FIG.
A schematic diagram showing the state of misalignment between the LED elements of the ED array and the light receiving elements of the image sensor, FIG. 4 is a perspective view showing another brightness measuring device to which an embodiment of the present invention is applied, and FIG. 5 is a conventional one. 1 is a perspective view showing a brightness measuring device to which an example of the LED array brightness measuring method of FIG. 11... LED array, 13... Image sensor,
50... LED array moving means, 51... First base part, 52... Second base part, 53... Third base part, 54, 58. 60...Stepping motor. Name of agent: Patent attorney Toshio Nakao (1st person, 2nd person)
Figure (a) (b) Figure 3 Rororo Rorororororororororororororororo00------- [[[x pg DI-----[10th mouth 4th Figure 5

Claims (1)

[Claims] While making the predetermined LED elements of the LED array emit light,
The ED array/image sensor relative position changing means
changing the relative positions of the ED array and the image sensor;
The position of the LED array is approximately determined in advance so that the light receiving element of the image sensor corresponding to the predetermined LED element receives light most efficiently, and in this positioning state, the L
While lighting the ED array, adjust and set the positional relationship between the LED array and the image sensor one or more times using the LED array/image sensor relative position changing means, and adjust the amount of light received for each element of the image sensor in each setting state. L characterized in that the brightness of the LED element is calculated based on the maximum amount of light received among one or more measured amounts of light received.
ED array brightness measurement method.